WO2020245260A1

WO2020245260A1 - Arrangement for generating electrical pulses

Info

Publication number: WO2020245260A1
Application number: PCT/EP2020/065463
Authority: WO
Inventors: Magnus Graas; Jan Lundgren; Fredrik HEMGREN; Roger Karlsson; Anders HARSTRÖM; Per Nilsson; Klas ELMQUIST; Per Benkowski; Jonas Gustafsson
Original assignee: Scandinova Systems AB
Current assignee: Nodica Group AB
Priority date: 2019-06-07
Filing date: 2020-06-04
Publication date: 2020-12-10
Anticipated expiration: 2021-12-07

Abstract

An arrangement (100) is disclosed, comprising at least one electrical energy storage module (30; 35) configured such that it can be charged or discharged, the at least one electrical energy storage module (30; 35) being connectable or connected to a load (40), and a power converter arrangement (50) connectable or connected to a power source (60) that is supplying AC power having a plurality of phases. The power converter arrangement (50) is configured to repeatedly charge at least one of the at least one electrical energy storage module (30; 35), wherein the at least one electrical energy storage module (30; 35) is connectable or connected to the load (40) such that when the at least one of the at least one electrical energy storage module (30; 35) is discharged, an electrical pulse is created to be received by the load (40) when the at least one electrical energy storage module (30; 35) is connected to the load (40), wherein by repeated charging and discharging of at least one of the at least one electrical energy storage module (30; 35), a plurality of successive electrical pulses are created to be received by the load (40) when the at least one electrical energy storage module (30; 35) is connected to the load (40). The power converter arrangement (50) comprises an input rectifier (70) arranged to receive AC power supplied by the power source, the input rectifier (70) being a multi-phase rectifier comprising a plurality of phase legs (71, 72, 73), the phase legs (71, 72, 73) being connectable or connected to respective ones of a plurality of phase conductors of the power source (60) carrying the plurality of phases of the AC power supplied by the power source (60), each phase leg (71, 72, 73) comprising at least one first switch unit (76; 76, 77) controllably switchable between at least a conducting state and a non-conducting state. At least one control module (80) is configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source (60) by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source (60).

Description

ARRANGEMENT FOR GENERATING ELECTRICAL PULSES

TECHNICAL FIELD

The present invention generally relates to the field of electrical systems.

Specifically, the present invention relates to an arrangement capable of generating electrical pulses, for delivery to a load.

BACKGROUND

Electrical pulses may be employed in a variety of applications, such as, for example, radar systems, particle accelerators, sterilization equipment, high-energy lasers, microwave systems, or medical devices. In such and other applications it may be desired or required to deliver one or more electrical pulses to a load.

An electrical energy storage unit or module such as a capacitor may be used to store electrical energy, which when discharged generates an electrical pulse, which can be delivered to the load, or a pulse transformer. The capacitor may be repeatedly charged by a power supply unit or arrangement connected to a power source.

Arrangements, systems or circuits which are employed for generating electrical pulses may be referred to as power modulators. Power modulators may employ a pulse transformer in order to obtain the required or desired voltage of the electrical pulses. In some applications it may be desired or even required with a capability of providing electrical pulses to the pulse transformer which have a relatively high power and/or a relatively high frequency.

SUMMARY

By way of the power supply being connected to the power source, the power supply unit or arrangement may directly provide a current by which the capacitor is charged. Thus, the power supply unit or arrangement may directly provide the pulsed load current. However, this may require a relatively large power supply unit or arrangement, having a relatively large power supplying capacity, and may further require drawing undesirable high transient currents from the power source, where the waveform of the current drawn from the power source is relatively much distorted from the normal sinusoidal shape. Drawing current from the power source in such a manner is usually not desired, since such distortion can cause relatively high root- mean- square (RMS) currents and negatively affect the power factor.

In view of the above, a concern of the present invention is to provide a system, arrangement, device, etc., capable of generating electrical pulses for delivery to a load, which system, arrangement, device, etc., comprises a power converter for drawing current from a power source and for repeatedly charging an electrical energy storage module, which when discharged creates an electrical pulse, and which system, arrangement, device, etc., allows for current drawn from the power source by power converter to be drawn relatively smoothly, or continuously, from the power source during charging of the electrical energy storage module.

A further concern of the present invention is to provide a system, arrangement, device, etc. capable of generating electrical pulses for delivery to a load, which system, arrangement, device, etc., comprises a power converter for drawing current from a power source and for repeatedly charging an electrical energy storage module, which when discharged creates an electrical pulse, and which system, arrangement, device, etc., allows for achieving relatively high power factor.

To address at least one of these concerns and other concerns, an arrangement and a method in an arrangement in accordance with the independent claims are provided. Preferred embodiments are defined by the dependent claims.

According to a first aspect, there is provided an arrangement comprising at least one electrical energy storage module. The at least one electrical energy storage module is configured such that it can be charged or discharged. The at least one electrical energy storage module is connectable or connected to a load (e.g., by means of one or more electrical conductors such as cables).

The arrangement according to the first aspect comprises a power converter arrangement, or power converter unit, connectable or connected to a power source (e.g., by means of one or more electrical conductors such as cables and/or busbars) that is supplying Alternating Current (AC) power having a plurality of phases. The power converter arrangement is arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source.

The power converter arrangement is configured to repeatedly charge at least one of the at least one electrical energy storage module. The at least one electrical energy storage module is connectable or connected to the load such that when the at least one of the at least one electrical energy storage module is discharged, an electrical pulse is created to be received by the load when the at least one electrical energy storage module is connected to the load. By repeated charging and discharging of at least one of the at least one electrical energy storage module, a plurality of successive electrical pulses are created to be received by the load when the at least one electrical energy storage module is connected to the load.

The power converter arrangement comprises an input rectifier arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source. The input rectifier is a multi-phase rectifier comprising a plurality of phase legs. The phase legs are connectable or connected to respective ones of a plurality of phase conductors of the power source carrying the plurality of phases of the AC power supplied by the power source. Each phase leg comprises at least one first switch unit controllably switchable between at least a conducting state and a non-conducting state. For each phase leg, by controlling timing of switching of the at least one first switch unit of the phase leg, the drawing of current from the corresponding phase conductor of the power source can be controlled.

The arrangement according to the first aspect comprises at least one control module connected to or comprised in the power converter arrangement. The at least one control module is configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to (or is proportional to, or comes closer to being proportional to) the waveform of the AC voltage of the power source.

By way of the input rectifier of the power converter and the at least one control module controlling the input rectifier as described in the foregoing, the arrangement according to the first aspect may facilitate or allow for an active power factor corrected multi-phase rectifier to be used for providing a pulsed load current. As described further in the following, the input rectifier may for example be a three-phase rectifier, and may be connectable or connected to a power source that is supplying three-phase AC power. By way of the controlling of the input rectifier as described in the foregoing, the arrangement according to the first aspect may facilitate or allow for current drawn from the power source by power converter to be drawn relatively smoothly, or continuously, from the power source during charging of the electrical energy storage module, and may facilitate or allow for achieving a relatively high power factor.

An ideal (1.0) power factor may generally be achieved only the waveform of the current drawn from the power source by the input rectifier corresponds to, or substantially corresponds to, the waveform of the AC voltage of the power source over a number of cycles of the waveform of the AC voltage of the power source that approximates the average power drawn from the power source.

The load may for example comprise or be constituted by one or more of a microwave amplifier, a klystron, a magnetron, or a particle emitter, such as, for example, an electron emitter (which may be referred to as an electron gun), which possibly may be connected with a transformer. The load may hence possibly comprise a transformer.

The power converter arrangement may possibly in alternative be referred to as a power supply arrangement.

The at least one control module (or at least one control module thereof, in case of several control modules being provided) may possibly in alternative be referred to as an active power factor correction module. The at least one control module may for example be connected to or comprised in the input rectifier.

The connection between the at least one control module and the power converter arrangement may be a communicative connection or coupling, which may be wired and/or wireless. The communicative connection or coupling between the at least one control module and the power converter arrangement may be realized or implemented for example by means of any appropriate wired and/or wireless communication means or techniques as known in the art.

The arrangement may comprise a sensor, which may be connectable or connected to the power source, and which may be configured to sense AC voltage of the power source (e.g., the waveform of the AC voltage of the power source).

By the waveform of the current drawn from the power source by the input rectifier corresponding to, or coming closer to corresponding to, the waveform of the AC voltage of the power source when the current drawn from the power source has been averaged over a plurality of cycles of the waveform of the AC voltage of the power source, it is meant that an instantaneous waveform of the current drawn from the power source by the input rectifier must not necessarily correspond to, or come closer to corresponding to, an instantaneous waveform of the AC voltage of the power source, but that such correspondence between the waveforms of the of the current drawn from the power source by the input rectifier and the AC voltage of the power source may be exhibited when considering an average of the waveform of the current drawn from the power source over several cycles of the waveform of the AC voltage of the power source.

In the light of the above, the at least one control module may be configured to control the timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source when the current drawn from the power source has been averaged over a plurality of cycles of the waveform of the AC voltage of the power source.

Thus, the at least one control module may be controlled so as to match the waveform of the current drawn from the power source by the input rectifier with the waveform of the AC voltage of the power source cycle-by-cycle, or over several cycles. In order to facilitate for correcting for any changes in load demand occurring over one or several cycles, the power converter arrangement (e.g., the input rectifier) may be provided with one or more electrical energy storage units such as capacitors.

As indicated in the foregoing, the power converter arrangement may be connectable or connected to a power source that is supplying AC power having at least three phases (e.g., having three phases). The input rectifier may comprise at least three phase legs (e.g., three phase legs). The phase legs may be connectable or connected (e.g., by means of one or more electrical conductors such as cables or busbars) to respective ones of the phase conductors of the power source carrying the phases of the AC power supplied by the power source.

Each or any of the phase legs of the input rectifier may in addition to the at least one first switch unit comprise one or more other components (e.g., semiconductor components), such as, for example, one or more diodes, which may be connected with the at least one first switch unit.

The input rectifier or power converter arrangement may be configured or arranged such that it does not require to be provided with a return line, or neutral line, or with a connection to neutral. One example of an input rectifier that does not require to be provided with a return line or neutral line (e.g., while still being able to operate as intended or according to specifications) is a so called Vienna Rectifier. The power converter arrangement may comprise a Vienna Rectifier. The input rectifier may hence comprise or be constituted by a Vienna Rectifier. In the context of the present application, by a Vienna Rectifier it may be meant a three-phase, three-switch, three-level pulse-width modulated rectifier possibly with a unidirectional power flow, or a three-phase diode bridge with an integrated boost converter. Other examples of input rectifiers that do not require to be provided with a return line or neutral line exist, and may be employed in the arrangement.

The at least one electrical energy storage module may for example comprise a capacitor, or possibly several capacitors which for example may be arranged so as to form a capacitor bank. At least one of the at least one electrical energy storage module may be selectively charged and discharged, partially or (substantially) completely. As mentioned in the foregoing, the power converter arrangement is configured to repeatedly charge at least one of the at least one electrical energy storage module. Thus, the power converter arrangement may be configured to supply power to the at least one electrical energy storage module (e.g., via an output rectifier, as will be described in the following), wherein the at least one electrical energy storage module may be charged by the power supplied thereto from the power converter arrangement. After the at least one electrical energy storage module has been charged (partially or completely), the at least one electrical energy storage module may be discharged (partially or completely), for example for generating at least one electrical pulse, which may be delivered to a load, possibly via a transformer (e.g., a so called pulse transformer, or voltage step-up transformer). Possibly, the electrical pulse may be delivered or conveyed directly to the load. After the at least one electrical energy storage module has been partially or fully discharged, it or they may then be (partially or completely) charged again by power that may be supplied thereto from the power converter arrangement, such that the at least one electrical energy storage module is repeatedly (e.g., cyclically or periodically) charged and discharged, whereby a series of electrical pulses may be generated. Thus, the power converter arrangement may be considered as a charger system for the at least one electrical energy storage module. In the case where the at least one electrical energy storage module comprises a capacitor or several capacitors for example arranged so as to form a capacitor bank, the power converter arrangement may be considered as a capacitor charger system. While in the following the term capacitor charger system may be used, it is to be understood that another or other types of electrical energy storage modules than capacitors may possibly be used, e.g., inductive electrical energy storage modules.

Capacitor charger systems are often used in applications in which electrical pulses with a relatively short duration and a relatively high current are desired or required, such as, for example, in power modulators, particle accelerators, etc. As indicated in the foregoing, the capacitor charger system may charge the capacitor(s), wherein an electrical pulse with a relatively high current may be generated by subsequent discharging (partial or complete) of the capacitor(s). The stability of the current of the electrical pulse may be directly or indirectly dependent on the voltage that is output by the capacitor charger system. Thus, if a relatively stable voltage (e.g., exhibiting relatively little variation over time) is output by the capacitor charger system, a resulting electrical pulse may in turn exhibit a relatively stable current (e.g., exhibiting relatively little variation over time). The speed of charging the capacitor(s) and the voltage output by the capacitor charger system may be regulated by means of a control system. The stability of the operation of the control system may depend on the precision by which the voltage output by the capacitor charger system can be measured. The voltage output by the capacitor charger system may for example be measured by means of a resistive voltage divider. The voltage output by the capacitor charger system may be distorted for example by high currents which are switched on and off in the capacitor charger system. Such current switching events may generate voltage distortions both relative to a common ground and as voltage variations at the output of the capacitor charger system, which may depend, e.g., on the inductance of the current path (e.g., cable inductance) from the output of the capacitor charger system to the capacitor(s). The arrangement may comprise a control system, or control module or controller, which may be configured to regulate (1) the speed of charging the at least one of the at least one electrical energy storage module by the power converter arrangement and (2) the voltage output by the power converter arrangement. Possibly, the control system, or control module or controller, may be configured to regulate the speed of charging the at least one of the at least one electrical energy storage module by the power converter arrangement and the voltage output by the power converter arrangement based on measured voltage output by the electrical energy storage module charger system (e.g., the capacitor charger system).

When the pulsed load is switched on - when (at least one of) the at least one electrical energy storage module is discharged to generate an electrical pulse to be received by the load - the at least one electrical energy storage module may drive the load. After the at least one electrical energy storage module has been discharged, it may be sensed (e.g., by the above-mentioned control system, or a voltage sensor) that the voltage over the at least one electrical energy storage module is low, responsive to which the power converter arrangement may be controlled so as to (re-)charge the at least one electrical energy storage module. In so doing, the power converter arrangement may operate at its maximum power until the at least one electrical energy storage module has been partially or (substantially) completely (re charged, after which the power converter arrangement may be controlled so as to enter an idle (non-charging) state until the next discharge of the at least one electrical energy storage module. In such a case, the (input rectifier of the) power converter arrangement may draw power from the power source in an intermittent, burst-like manner, which may be detrimental to the power factor.

In order to facilitate achieving a relatively high power factor, for example in such cases, the power converter arrangement may be configured to be controllable at least with respect to a rate of charging of the at least one of the at least one electrical energy storage module. The power converter arrangement may be configured to be controllable such that the rate of charging of the at least one of the at least one electrical energy storage module becomes lower than a maximum rate of charging of the at least one of the at least one electrical energy storage module that the power converter arrangement is capable of.

The at least one control module may be configured to, based on a time interval between successive discharges of the at least one of the at least one electrical energy storage module, control the rate of charging of the at least one of the at least one electrical energy storage module by the power converter arrangement such that the duration of charging of the at least one of the at least one electrical energy storage module between the successive discharges is a selected portion of the time interval between the successive discharges. The selected portion of the time interval between the successive discharges may preferably be as close to the full time interval as practicably possible. The selected portion of the time interval between the successive discharges may for example be 70%, 80%, 90%, 95%, or 98% or more, of the full time interval.

Thus, the power converter arrangement may be controlled so as to control the rate of charging of the at least one of the at least one electrical energy storage module between subsequent discharges of the at least one of the at least one electrical energy storage module so that the duration of the charging operation takes up a selected portion of the time period between the subsequent discharges (or between successive electrical pulses), e.g., so that the duration of the charging operation takes up the entire or almost the entire time period between the subsequent discharges.

For example, the power converter arrangement may be configured to charge the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement. The power converter arrangement may be configured to be controllable with respect to at least magnitude of the charging current and/or duration of supplying of the charging current, whereby the rate of charging of the at least one of the at least one electrical energy storage module can be controlled.

The time interval between successive discharges of the at least one of the at least one electrical energy storage module may for example be determined or set as per requirements relating to the load, e.g. the pulse repetition rate that may be required by the load, which may depend at least on the type and application of the load. Other factors that in addition or in alternative may affect or possibly constrain the time interval between successive discharges of the at least one of the at least one electrical energy storage module are the required or desired voltage and/or energy of the electrical pulses, tolerances of capacitance values of the at least one electrical energy storage module, and/or temperature variation tolerances.

By way of controlling the power converter arrangement so as to control the rate of charging of the at least one of the at least one electrical energy storage module between subsequent discharges of the at least one of the at least one electrical energy storage module, so that the duration of the charging operation takes up a selected portion of the time period between the subsequent discharges (or between successive electrical pulses) (e.g., so that the duration of the charging operation takes up the entire or almost the entire time period between the subsequent discharges), the (input rectifier of the) power converter arrangement may draw power from the power source in a less or no intermittent, burst-like manner, and instead in a relatively smooth, or continuous, manner, which may be helpful for achieving a relatively high power factor.

The arrangement may comprise at least one sensor for facilitating controlling of the power converter arrangement so as to control the rate of charging of the at least one of the at least one electrical energy storage module. The at least one sensor may be connected between the power converter arrangement and the at least one electrical energy storage module (e.g., by means of one or more electrical conductors such as cables), and/or may be comprised in the power converter arrangement. The at least one sensor may be configured to directly or indirectly sense voltage over the at least one electrical energy storage module or some other quantity from which the charge state of the at least one electrical energy storage module may be derived. The at least one sensor could for example comprise a resistive voltage divider, or a voltage comparator, and may sense voltage over the at least one electrical energy storage module and compare it with a reference value to derive the charge state of the at least one electrical energy storage module (the comparison could in alternative or in addition be carried out by the at least one control module, for example).

The arrangement may comprise at least one second switch unit. The at least one second switch unit may alternatively be referred to as electrical energy storage module switch unit. The at least one second switch unit may be controllably switchable between at least a conducting state and a non-conducting state. The at least one second switch unit may be connected to the power converter arrangement and to the at least one electrical energy storage module, respectively, such that the power converter arrangement charges the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement, or the at least one electrical energy storage module is discharged so as to create an electrical pulse to be received by the load, based on switching of the at least one second switch unit.

The power converter arrangement may charge the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement, or the at least one electrical energy storage module may be discharged so as to create an electrical pulse to be received by the load, based on switching of the at least one second switch unit for example between at least the conducting state and the non-conducting state thereof.

The arrangement may comprise an output rectifier. The input rectifier may be connected to the at least one electrical energy storage module via the output rectifier. The output rectifier may be connected between the input rectifier and the at least one electrical energy storage module. The at least one electrical energy storage module may be connected between the output rectifier and the load. The power converter arrangement may be configured to supply power to the at least one electrical energy storage module via the output rectifier.

The output rectifier may for example comprise at least one diode, which for example may at least in part based on silicon, or silicon carbide. In the context of the present application, by a diode being at least in part based on silicon or silicon carbide, it is meant that the semiconductor component(s) of the diode is/are made partly or (substantially) completely of silicon or silicon carbide, or possibly of some material comprising silicon or silicon carbide. Possibly, one or more semiconductor components of any other element which may be included in the output rectifier (e.g., a switching element or device such as a transistor) may be at least in part based on silicon carbide.

The output rectifier may for example comprise a plurality of electrically interconnected diodes. At least some diodes of the plurality of diodes may at least in part be based on silicon carbide. The plurality of diodes may for example be electrically

interconnected so as to form at least one bridge circuit. However, it is to be understood that another or other types of configurations of the electrical interconnection of the plurality of diodes are possible.

The input rectifier may be configured to convert the received AC power into Direct Current (DC) power.

The arrangement may comprise a DC-DC converter (or possibly several DC- DC converters), which may be connected between the input rectifier and the at least one electrical energy storage module and between the input rectifier and the output rectifier. The DC-DC converter may facilitate or allow for electrical isolation between input rectifier and the load/ electrical energy storage module. The DC-DC converter may for example comprise or be constituted by one or more of a resonant full-bridge DC-DC converter, a full-bridge DC- DC converter, or a half-bridge DC-DC converter.

As mentioned in the foregoing, the arrangement may comprise at least one second switch unit, which may be controllably switchable between at least a conducting state and a non-conducting state. The at least one second switch unit may be connected to the power converter arrangement via the output rectifier and to the at least one electrical energy storage module, respectively, such that the power converter arrangement charges the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement, or the at least one electrical energy storage module is discharged so as to create an electrical pulse to be received by the load, based on switching of the at least one second switch unit.

Each or any of the switching devices or switching modules may for example comprise one or more semiconductor-based switching elements or components, for example one or more transistors such as, for example, insulated-gate bipolar transistors (IGBTs) and/or metal oxide semiconductor field-effect transistors (MOSFETs), and/or, for example, one or more gate turn-off thyristors (GTOs) and/or integrated gate-commutated thyristors (IGTOs).

In the context of the present application, by a non-conducting state of a switch unit it is meant a state where there is no or only very little conduction of current through the switch unit.

Thus, the switch unit may be switchable so as to (substantially) stop the switch unit from conducting current.

According to a second aspect there is provided a system, which may comprise a load and an arrangement according to the first aspect. The at least one electrical energy storage module of the arrangement according to the first aspect may be connectable or connected to the load.

According to a third aspect there is provided a method in an arrangement. The arrangement comprises at least one electrical energy storage module. The at least one electrical energy storage module is configured such that it can be charged or discharged. The at least one electrical energy storage module is connectable or connected to a load. The arrangement comprises a power converter arrangement connectable or connected to a power source that is supplying Alternating Current (AC) power having a plurality of phases. The power converter arrangement is arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source. The power converter arrangement is configured to repeatedly charge at least one of the at least one electrical energy storage module. The at least one electrical energy storage module is connectable or connected to the load such that when the at least one of the at least one electrical energy storage module is discharged, an electrical pulse is created to be received by the load when the at least one electrical energy storage module is connected to the load. By repeated charging and discharging of at least one of the at least one electrical energy storage module, a plurality of successive electrical pulses are created to be received by the load when the at least one electrical energy storage module is connected to the load. The power converter arrangement comprises an input rectifier arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source. The input rectifier is a multi-phase rectifier comprising a plurality of phase legs. The phase legs are connectable or connected to respective ones of a plurality of phase conductors of the power source carrying the plurality of phases of the AC power supplied by the power source. Each phase leg comprises at least one first switch unit controllably switchable between at least a conducting state and a non-conducting state. For each phase leg, by controlling timing of switching of the at least one first switch unit of the phase leg, the drawing of current from the corresponding phase conductor of the power source can be controlled.

The method according to the third aspect comprises carrying out active power factor correction, wherein the carrying out of active power factor correction comprises controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source.

According to a fourth aspect there is provided a control module for use in conjunction with an arrangement according to the first aspect. The control module is connected to or comprised in the power converter arrangement of the arrangement according to the first aspect. The control module is configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source.

According to a fifth aspect there is provided a computer program product configured to, when executed in a control module according to the fourth aspect or in a control module of an arrangement according to the first aspect, perform a method according to the third aspect.

According to a sixth aspect there is provided a computer-readable storage medium on which there is stored a computer program product configured to, when executed in a control module according to the fourth aspect or in a control module of an arrangement according to the first aspect, perform a method according to the third aspect.

The computer-readable storage medium may for example include a Digital Versatile Disc (DVD) or a floppy disk or any other suitable type of computer-readable means or computer-readable (digital) storage medium, such as, but not limited to, a memory such as, for example, nonvolatile memory, a hard disk drive, a Compact Disc (CD), a Flash memory, magnetic tape, a Universal Serial Bus (USB) memory device, a Zip drive, etc.

The control module may alternatively be referred to as a control unit, or control circuitry. The control module may for example include or be constituted by any suitable central processing unit (CPU), microcontroller, digital signal processor (DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA), etc., or any combination thereof. The control module may optionally be capable of executing software instructions stored in a computer program product e.g. in the form of a memory. The memory may for example be any combination of read and write memory (RAM) and read only memory (ROM). The memory may comprise persistent storage, which for example can be a magnetic memory, an optical memory, a solid state memory or a remotely mounted memory, or any combination thereof.

Further objects and advantages of the present invention are described in the following by means of exemplifying embodiments. It is noted that the present invention relates to all possible combinations of features recited in the claims. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the description herein. Those skilled in the art realize that different features of the present invention can be combined to create embodiments other than those described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplifying embodiments of the present invention will be described below with reference to the accompanying drawings.

Figure 1 is a schematic circuit diagram of an arrangement according to one or more embodiments of the present invention.

Figures 2 to 5 are schematic circuit diagrams of a phase leg of an input rectifier or multi-phase rectifier in accordance with embodiments of the present invention.

Figures 6 to 8 are schematic circuit diagrams of arrangements according to one or more embodiments of the present invention.

Figure 9 is a schematic flowchart of a method according to one or more embodiments of the present invention.

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate embodiments of the present invention, wherein other parts may be omitted or merely suggested.

DETAILED DESCRIPTION

The present invention will now be described hereinafter with reference to the accompanying drawings, in which exemplifying embodiments of the present invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments of the present invention set forth herein; rather, these embodiments are provided by way of example so that this disclosure will convey the scope of the present invention to those skilled in the art.

Figure 1 is a schematic circuit diagram of an arrangement 100 according to one or more embodiments of the present invention.

The arrangement 100 comprises an electrical energy storage module 30, which is configured such that it can be charged or discharged. The electrical energy storage module 30 is connectable or connected to a load 40.

The load 40 may for example comprise or be constituted by a transformer, which in turn may be connected to some other component (not shown in Figure 1) to which it may be desired or required to deliver electrical pulse(s). The load 40 or the other component mentioned above may for example comprise or be constituted by a microwave amplifier, a klystron, and/or a magnetron.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the electrical energy storage module 30 may for example comprise a capacitor, or possibly several capacitors which may be arranged so as to form a capacitor bank. In the following the electrical energy storage module 30 may be referred to as a capacitor. It is however to be understood that another or other types of electrical energy storage modules than capacitors may possibly be used.

The arrangement 100 comprises a power converter arrangement 50. The power converter arrangement 50 is connectable or connected to a power source 60 that is supplying Alternating Current (AC) power having a plurality of phases. The power converter arrangement 50 is arranged to receive the AC power supplied by the power source 60 when the power converter arrangement 50 is connected to the power source 60.

The power source 60 may for example supply three-phase AC power. The power source 60 may for example comprise or be constituted by an electrical grid, which may supply three-phase AC power, e.g., mains electric power.

The power converter arrangement 50 is configured to repeatedly charge the electrical energy storage module 30. The electrical energy storage module 30 is connectable or connected to the load 40 such that when the electrical energy storage module 30 is discharged, an electrical pulse is created to be received by the load 40 when the electrical energy storage module 30 is connected to the load 40. By repeated charging and discharging of the electrical energy storage module 30, a plurality of successive electrical pulses can be created to be received by the load 40 when the electrical energy storage module 30 is connected to the load 40.

The power converter arrangement comprises an input rectifier 70.

The input rectifier 70 is arranged to receive the AC power supplied by the power source 60 when the power converter arrangement 50 is connected to the power source 60. The input rectifier 70 is or comprises a multi-phase rectifier, comprising a plurality of phase legs 71, 72, 73.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the power source 60 is supplying three-phase AC power, and the input rectifier 70 or multi-phase rectifier comprises three phase legs 71, 72, 73, each phase leg 71, 72, 73 corresponding to one of the three phases of the AC power supplied by the power source 60. It is however to be understood that the input rectifier 70 or multi-phase rectifier is not limited to three phase legs, and could comprise two or four or more phase legs, each of which may correspond to a respective one of phases of AC power that may be supplied by the power source 60.

The phase legs 71, 72, 73 are connectable or connected to respective ones of a plurality of phase conductors of the power source 60 carrying the plurality of phases of the AC power supplied by the power source 60. Possibly, the phase legs 71, 72, 73 may be connectable or connected to respective ones of a plurality of phase conductors of the power source 60 carrying the plurality of phases of the AC power supplied by the power source 60 via respective ones of inductive components 61, 62, 63, as illustrated in Figure 1.

Each phase leg 71, 72, 73 comprises at least one first switch unit (not shown in Figure 1; cf. Figures 2 to 5) controllably switchable between at least a conducting state and a non-conducting state, wherein, for each phase leg 71, 72, 73, by controlling timing of switching of the at least one first switch unit of the phase leg 71, 72, 73, the drawing of current from the corresponding phase conductor of the power source 60 can be controlled. As illustrated in Figures 2 to 5 and described further in the following with reference to Figures 2 to 5, the at least one first switch unit of each or any of the phase legs 71, 72, 73 may for example comprise one or more semiconductor switching devices.

The arrangement 100 comprises control module 80, which may be connected to or comprised in the power converter arrangement 50. The connection between the control module 80 and the power converter arrangement 50 may be a communicative connection or coupling, which may be wired and/or wireless. The communicative connection or coupling between the control module 80 and the power converter arrangement 50 may be realized or implemented for example by means of any appropriate wired and/or wireless communication means or techniques as known in the art. The control module 80 may for example include or be constituted by any CPU, microcontroller, DSP, ASIC, FPGA, etc., or any combination thereof.

The control module 80 is configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit of each phase leg 71, 72, 73 such that the waveform of the current drawn from the power source 60 by the input rectifier 70 corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source 60. The control module 80 may be configured to control the timing of switching of the at least one first switch unit of each phase leg 71, 72, 73 such that the waveform of the current drawn from the power source 60 by the input rectifier 70 corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source 60 when the current drawn from the power source 60 has been averaged over a plurality of cycles of the waveform of the AC voltage of the power source 60.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the arrangement 100 may comprise an output rectifier 10, and possibly a Direct Current (DC)-DC converter 90. As illustrated in Figure 1, the DC-DC converter 90 may be connected between the input rectifier 70 and the electrical energy storage module 30, and between the input rectifier 70 and the output rectifier 10.

As illustrated in Figure 1, the input rectifier 70 may be connected to the electrical energy storage module 30 via the output rectifier 10. The output rectifier 10 may be connected between the input rectifier 70 and the electrical energy storage module 30. The electrical energy storage module 30 may be connected between the output rectifier 10 and the load 40. The power converter arrangement 50 may be configured to supply power to the electrical energy storage module 30 via the output rectifier 10.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the arrangement 100 may comprise a second switch unit 31, which may be controllably switchable between at least a conducting state and a non-conducting state (or possibly several second switch units, each of which may be controllably switchable between at least a conducting state and a non-conducting state). The second switch unit 31 may be connected to the power converter arrangement 50 via the output rectifier 10 and to the electrical energy storage module 30, respectively, such that the power converter arrangement 50 charges the electrical energy storage module 30 by way of a charging current supplied by the power converter arrangement 50, or the electrical energy storage module 30 is discharged so as to create an electrical pulse to be received by the load 40, based on switching of the second switch unit 31. As illustrated in Figure 1, the switch unit 31 and the load 40 may be connected in parallel. And as further illustrated in Figure 1, the switch unit 31 and the output rectifier 10 may be connected in parallel.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the DC-DC converter 90 may be based on, or comprise or be constituted by, a resonant full-bridge DC-DC power converter. The resonant full-bridge DC- DC power converter comprises a symmetric switch-based bridge network 23, 24, 26, 27, an internal transformer 29, and a resonant circuit including a capacitive component for example in the form of a capacitor 28 (or several capacitors). The symmetric switch-based bridge network 23, 24, 26, 27 comprises two pairs of electronically controllable semiconductor switching devices 23, 24 and 26, 27. Any one of each of the semiconductor switching devices 23, 24, 26, 27 may for example comprise one or more IGBTs, MOSFETs, GTOs and/or IGTOs. As illustrated in Figure 1, the capacitor 28 of the resonant circuit may be connected in a series path with a primary winding of the internal transformer 29. The resonant circuit may further include at least one inductive component (not shown in Figure 1), which may be connected between the capacitor 28 and the internal transformer 29. The at least one inductive component of the resonant circuit may in addition or in alternative be integrated in the internal transformer 29. For example, the at least one inductive component of the resonant circuit may be integrated with a primary winding of the internal transformer 29. As illustrated in Figure 1, the DC -DC converter 90 may be electrically connected to the output rectifier 10 via a secondary winding of the internal transformer 29.

The DC-DC converter 90 is not limited to being based on, or comprising or being constituted by, a resonant full-bridge DC-DC power converter. In alternative, or in addition, the DC-DC converter 90 could be based on, or comprise or be constituted by, a full- bridge DC-DC power converter, and/or a half-bridge DC-DC power converter. A full-bridge bridge DC-DC power converter may be configured similarly to the resonant full-bridge DC- DC power converter illustrated in Figure 1, but with the capacitor 28 omitted. A half -bridge bridge DC-DC power converter may be configured similarly to the resonant full-bridge DC- DC power converter illustrated in Figure 1, but with the capacitor 28 omitted and for example the two semiconductor switching devices 23, 24 being omitted or each of them being replaced with one or more capacitors.

The output rectifier 10 may comprise a diode based rectifier circuit. The output rectifier 10 may comprise at least one diode at least in part based on silicon, or silicon carbide. The output rectifier 10 may comprise plurality of electrically interconnected diodes, for example four electrically interconnected diodes 11, 12, 13, 14, such as illustrated in Figure 1. It is however to be understood that the output rectifier 10 could comprise less or more than four diodes, and possibly only a single diode. In accordance with the one or more

embodiments of the present invention illustrated in Figure 1, the diodes 11, 12, 13, 14 are electrically interconnected so as to form a bridge circuit. It is however to be understood that the configuration of the electrical interconnection of the diodes 11, 12, 13, 14 illustrated in Figure 1 is according to an example, and that variations are possible. At least one, some, or even all of the diodes 11, 12, 13, 14 of the output rectifier 10 may be at least in part based on silicon carbide. This may imply that the semiconductor component(s) of at least one, some or even all of the diodes 11, 12, 13, 14 may be made partly or (substantially) completely of silicon carbide, or possibly of some material comprising silicon carbide. In accordance with one or more embodiments of the present invention, each diode 11, 12, 13, 14 of the output rectifier 10 may be a silicon carbide based diode.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the input rectifier 70 may comprise or be constituted by a so called Vienna Rectifier. A Vienna rectifier is an example of an input rectifier that does not require to be provided with a return line or neutral line (e.g., while still being able to operate as intended or according to specifications). Thus, the input rectifier 70 of the arrangement 100 illustrated in Figure 1 may not require to be provided with a return line, or neutral line, or with a connection to neutral. Other examples of input rectifiers that are not required to be provided with a return line or neutral line exist, and may in alternative or in addition to a Vienna rectifier be employed in the arrangement 100.

As illustrated in Figure 1, the input rectifier 70 comprises - in addition to the phase legs 71, 72, 73 - electrical energy storage modules 74, 75. Although there is illustrated two electrical energy storage modules 74, 75 in Figure 1, it is to be understood that the input rectifier 70 could comprise fewer or more than two electrical energy storage modules, e.g., one electrical energy storage module or three or more electrical energy storage modules. In accordance with the one or more embodiments of the present invention illustrated in Figure 1, each of the electrical energy storage modules 74, 75 of the input rectifier 70 may for example comprise a capacitor, or possibly several capacitors which may be arranged so as to form a capacitor bank. It is however to be understood that another or other types of electrical energy storage modules than capacitors may possibly be used in the input rectifier 70.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the charging current that may be supplied by the power converter arrangement 50 via the output rectifier 10 when the switch unit 31 is switched into the non conducting state may flow out of the power converter arrangement 50 via the conductor of the two conductors connected to the power converter arrangement 50 via the output rectifier 10 that is uppermost in Figure 1, and return to the power converter arrangement 50 via the conductor of the two conductors connected to the power converter arrangement 50 via the output rectifier 10 that is lowermost in Figure 1, as indicated by the arrows IC in Figure 1.

The two above-mentioned conductors may for example be connected to two terminals of the output rectifier 10, as illustrated in Figure 1.

Further in accordance with the one or more embodiments of the present invention illustrated in Figure 1, an electrical pulse, which may be generated when the electrical energy storage module 30 is discharged upon the switch unit 31 being switched into the conducting state, may flow in the direction indicated by the arrow IP in Figure 1. The duration of an electrical pulse may for example be 1 ms or about 1 ms, but is not limited thereto, and could be longer, or shorter.

The power converter arrangement 50 may be configured to be controllable at least with respect to a rate of charging of the electrical energy storage module 30. The power converter arrangement 50 may be configured to be controllable such that the rate of charging of the electrical energy storage module 30 becomes lower than a maximum rate of charging of the electrical energy storage module 30 that the power converter arrangement 50 is capable of. As mentioned in the foregoing, the power converter arrangement 50 may be configured to charge the electrical energy storage module 30 by way of a charging current supplied by the power converter arrangement 50. The power converter arrangement 50 may be configured to be controllable with respect to at least magnitude of the charging current and/or duration of supplying of the charging current, whereby the rate of charging of the at least one of the electrical energy storage module 30 can be controlled. The arrangement 100 may comprise a sensor (or several sensors; not shown in Figure 1) for facilitating controlling of the power converter arrangement 50 so as to control the rate of charging of the electrical energy storage module 30. The sensor may be connected between the power converter arrangement 50 and the electrical energy storage module 30 (e.g., by means of one or more electrical conductors such as cables), and/or may be comprised in the power converter arrangement 50. The sensor may be configured to directly or indirectly sense voltage over the electrical energy storage module 30 or some other quantity from which the charge state of the electrical energy storage module 30 may be derived. The sensor could for example comprise a resistive voltage divider, or a voltage comparator, and may sense voltage over the electrical energy storage module 30 and compare it with a reference value to derive the charge state of the electrical energy storage module 30. Such comparison could in alternative or in addition be carried out by another entity, such as the control module 80, for example.

The control module 80 may be configured to, based on a time interval between successive discharges of the at least one of the electrical energy storage module 30, control the rate of charging of the electrical energy storage module 30 by the power converter arrangement 50 such that the duration of charging of the at least one of the electrical energy storage module 30 between the successive discharges is a selected portion of the time interval between the successive discharges. The selected portion of the time interval between the successive discharges may preferably be as close to the full time interval as practicably possible. The selected portion of the time interval between the successive discharges may for example be 70%, 80%, 90%, 95%, or 98% or more, of the full time interval. Possibly, the power converter arrangement 50 may be controlled so as to control the rate of charging of the electrical energy storage module 30 between subsequent discharges thereof so that the duration of the charging operation takes up the entire or almost the entire time period between the subsequent discharges. The time interval between successive discharges of the electrical energy storage module 30 may for example be determined or set as per requirements relating to the load 40, e.g. as per the pulse repetition rate that may be required by the load 40, which may depend at least on the type and application of the load 40. Other factors that in addition or in alternative may affect or possibly constrain the time interval between successive discharges of the electrical energy storage module 30 are the required or desired voltage and/or energy of the electrical pulses, tolerances of capacitance values of the electrical energy storage module 30, and/or temperature variation tolerances. By way of controlling the power converter arrangement 50 so as to control the rate of charging of the electrical energy storage module 30 between subsequent discharges thereof, so that the duration of the charging operation takes up a selected portion of the time period between the subsequent discharges (or between successive electrical pulses) - e.g., so that the duration of the charging operation takes up the entire or almost the entire time period between the subsequent discharges - the (input rectifier 70 of the) power converter arrangement 50 may draw power from the power source 60 in a less or no intermittent, burst-like manner, and instead in a relatively smooth, or continuous, manner, which may be helpful for achieving a relatively high power factor.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the arrangement 100 comprises a flyback protection unit 32. The flyback protection unit 32 is connected to the switch unit 31. The flyback protection unit 32 is configured to protect the switch unit 31 against flyback upon the switch unit 31 being switched into the non-conducting state. As illustrated in Figure 1, the flyback protection unit 32 and the switch unit 31 may be connected in parallel. And as further illustrated in Figure 1, the flyback protection unit 32 and the load 40 may be connected in parallel.

In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the flyback protection unit 32 comprises a diode, which may be referred to as a free-wheeling diode.

In accordance with one or more other embodiments of the present invention, the flyback protection unit 32 could comprise several diodes, for example arranged in at least one series connection of diodes, and possibly several series connections of diodes with the different series connections being electrically connected in parallel in relation to each other.

Any diode which may be included in the flyback protection unit 32 may comprise, for example, in principle any type of semiconductor diode, possibly a Zener diode.

For example, the switch unit 31 may during the delivery of an electrical pulse have been switched into the conducting state for such a period of time that an inductance (not shown) between the switch unit 31 and the load 40 has been fully energized. The inductance may possibly not be a separate electrical component in the arrangement 100, but could for example be the inductance of the conductor between the flyback protection circuit 32 and the load 40. When the switch unit 31 is switched into the non-conducting state, the discharge from the capacitor 30 may be suddenly reduced or interrupted. This may entail that a surge of voltage, or voltage spike, is created, which in turn may cause an overvoltage condition in the switch unit 31 that may damage or even destroy the switch unit 31. The flyback protection unit 32 may protect against such an overvoltage condition in the switch unit 31 by allowing for the inductance to draw current from itself in a continuous circuit until the energy in the inductance has been sufficiently dissipated, e.g., by means of resistive losses in conductors in the arrangement 100. The flyback protection unit 32 is arranged in a current path which bypasses the load 40. This may for example be implemented by means of an electrical configuration such as illustrated in Figure 1. In accordance with the one or more embodiments of the present invention illustrated in Figure 1, the flyback protection unit 32 and the switch unit 31 may be connected in parallel, and the flyback protection unit 32 and the load 40 may in addition or alternatively be connected in parallel.

The flyback protection unit 32 may be configured such that a relation between the voltage drop across the flyback protection unit 32 for the charging current and the voltage drop across the load 40 for the charging current is such so as to cause the charging current, which may be supplied by the power converter arrangement 50 via the output rectifier 10 when the switch unit 31 is switched into the non-conducting state, to be directed via the load 40 at least to some extent. Thus, by means of the above-mentioned configuration of the flyback protection unit 32, at least a part or portion of the charging current may be directed via the load 40 (which, e.g., may comprise a transformer), and not only via the current path in which the flyback protection unit 32 is arranged and which current path bypasses the load 40.

As indicated in the foregoing, the load 40 may be constituted by or comprise a transformer, which in the following will be referred to as a load transformer (or pulse transformer). The charging current, or at least a part or portion thereof, may be directed via the load transformer by means of the charging current or at least a part or portion thereof being conveyed through the winding(s) of the load transformer. Between electrical pulses - e.g., after an electrical pulse has been terminated and during the charging of the capacitor 30 in preparation for starting delivery of the next electrical pulse to the load transformer - the core of the load transformer should preferably be reset to its proper magnetic operating point, for example by removing all, or substantially all, energy from the core. Alternatively, the core may not be demagnetized when the next electrical pulse begins, but may for example be reset to a magnetic operating point in which the core is magnetized so as to exhibit a negative magnetic field strength. For example, provided the magnetic field strength of the core can vary between -Bi and Bi, where Bi > 0, the core may be reset (or‘biased’) prior to the next electrical pulse begins so that it has a magnetic field strength -Bi. The‘available’ operating range of the load transformer before saturation of the core of the load transformer possibly may occur could then hence be 2Bi. By resetting the core after each electrical pulse that has been delivered to the load transformer, the full - or a substantially full - operating range of the load transformer may be available for the next electrical pulse that is received by the load transformer. The voltage drop across the flyback protection unit 32 for the charging current may determine the voltage over the load transformer (e.g., the voltage over at least one (primary) winding of the load transformer), which in turn may govern the extent to which the part or portion of the charging current that is directed via the load transformer contributes to the resetting of the core. Figures 2 to 5 are schematic circuit diagrams of a phase leg 71 of an input rectifier or multi-phase rectifier in accordance with one or more embodiments of the present invention. For example, each or any of the phase legs 71, 72, 73 illustrated in Figure 1 may be configured and/or arranged in accordance with the phase leg 71 illustrated in any of Figures 2 to 5.

In accordance with the one or more embodiments of the present invention illustrated in Figure 2, the phase leg 71 comprises two semiconductor switching devices 76, 77, each of which for example may comprise one or more IGBTs, MOSFETs, GTOs and/or IGTOs, and diodes 101, 102, 103, 104.

In accordance with the one or more embodiments of the present invention illustrated in Figure 3, the phase leg 71 comprises a semiconductor switching device 76, which for example may comprise one or more IGBTs, MOSFETs, GTOs and/or IGTOs, and diodes 105, 106, 107, 108, 109, 110.

In accordance with the one or more embodiments of the present invention illustrated in Figure 4, the phase leg 71 comprises two semiconductor switching devices 76, 77, each of which for example may comprise one or more IGBTs, MOSFETs, GTOs and/or IGTOs, and diodes 111, 112, 113, 114.

In accordance with the one or more embodiments of the present invention illustrated in Figure 5, the phase leg 71 comprises a semiconductor switching device 76, which for example may comprise one or more IGBTs, MOSFETs, GTOs and/or IGTOs, and diodes 115, 116, 117, 118, 119, 120.

Figure 6 is a schematic circuit diagram of an arrangement 100 according to one or more embodiments of the present invention. The arrangement 100 illustrated in Figure 6 is similar to the arrangement 100 illustrated in Figure 1, and the same reference numerals in Figures 1 and 6 indicate the same or similar components, having the same or similar function.

The arrangement 100 illustrated in Figure 6 differs from the arrangement 100 illustrated in Figure 1 in that the flyback protection unit 32 illustrated in Figure 1 has been replaced with a switch unit 33, which may be located in the same or a similar position in relation to the other components of the arrangement 100 (and be similarly electrically connected to the other components) as the flyback protection unit 32. The switch unit 33 may be controllably switchable between at least a conducting state and a non-conducting state, and may for example comprise one or more semiconductor-based switching elements or components, such as, for example, one or more IGBTs, MOSFETs, GTOs and/or IGTOs. As illustrated in Figure 6, the switch units 31 and 33 may for example be electrically connected in parallel. And as further illustrated in Figure 6, the switch unit 33 and the load 40 may be electrically connected in parallel.

The switch unit 33 may provide functionality that is similar to functionality of the flyback protection unit 32 illustrated in Figure 1. For example, during charging of the capacitor 30, by means of a charging current supplied by the power converter arrangement 50 when the switch unit 31 is into the non-conducting state as described in the foregoing, by switching the switch unit 33 into a non-conducting state, it may be ensured that at least a part or portion of the charging current may be directed via the load 40 (which, e.g., may comprise a transformer).

Figure 7 is a schematic circuit diagram of an arrangement 100 according to one or more embodiments of the present invention. The arrangement 100 illustrated in Figure 7 is similar to the arrangement 100 illustrated in Figure 1, and the same reference numerals in Figures 1 and 7 indicate the same or similar components, having the same or similar function.

The arrangement 100 illustrated in Figure 7 differs from the arrangement 100 illustrated in Figure 1 in that it does not include the flyback protection unit 32 illustrated in Figure 1. The arrangement 100 illustrated in Figure 7 differs from the arrangement 100 illustrated in Figure 1 in that it comprises an electrical energy storage module 35 which is electrically connected in parallel with the output rectifier 10.

In accordance with the one or more embodiments of the present invention illustrated in Figure 7, the electrical energy storage module 35 may for example may comprise a capacitor, or possibly several capacitors which may be arranged so as to form a capacitor bank. In the following the electrical energy storage module 35 may be referred to as a capacitor. It is however to be understood that another or other types of electrical energy storage modules than capacitors may possibly be used. By arranging the capacitor 35 in parallel with the output rectifier 10, the capacitor 35 may exhibit a functionality similar to a filter capacitor, and which may provide for a relatively high stability of voltage output from the output rectifier 10.

The arrangement 100 illustrated in Figure 7 differs from the arrangement 100 illustrated in Figure 1 in that it comprises a switch unit 34 which is electrically connected in series with the load 40. The capacitor 35 can be charged or discharged. The switch unit 34 is connected to the power converter arrangement 50 (via the output rectifier 10) and to the capacitor 35, respectively, such that when the switch unit 34 is switched into the non conducting state, the power converter arrangement 50 may charge the capacitor 35 by way of a charging current supplied by the power converter arrangement 50, and when the switch unit 34 is switched into the conducting state, the capacitor 35 is discharged so as to create an electrical pulse. The capacitor 35 is electrically connected to the load 40, such that electrical pulse(s) created by discharge of the capacitor 35 is/are received by the load 40.

Figure 8 is a schematic circuit diagram of an arrangement 100 according to one or more embodiments of the present invention. The arrangement 100 illustrated in Figure 8 is similar to the arrangement 100 illustrated in Figure 7, and the same reference numerals in Figures 7 and 8 indicate the same or similar components, having the same or similar function. The arrangement 100 illustrated in Figure 8 differs from the arrangement 100 illustrated in Figure 7 in that that the positions of the switch unit 34 and the load 40 have been changed. Similarly to the arrangement 100 illustrated in Figure 7, in the arrangement 100 illustrated in Figure 8, the switch unit 34 is connected to the power converter arrangement 50 (via the output rectifier 10) and to the capacitor 35, respectively, such that when the switch unit 34 is switched into the non-conducting state, the power converter arrangement 50 may charge the capacitor 35 by way of a charging current supplied by the power converter arrangement 50, and when the switch unit 34 is switched into the conducting state, the capacitor 35 is discharged so as to create an electrical pulse. The capacitor 35 is electrically connected to the load 40, such that electrical pulse(s) created by discharge of the capacitor 35 is/are received by the load 40.

Figure 9 is a schematic flowchart of a method 200 according to one or more embodiments of the present invention. The method 200 is a method in an arrangement. The arrangement comprises at least one electrical energy storage module. The at least one electrical energy storage module is configured such that it can be charged or discharged. The at least one electrical energy storage module is connectable or connected to a load. The arrangement comprises a power converter arrangement connectable or connected to a power source that is supplying AC power having a plurality of phases. The power converter arrangement is arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source. The power converter arrangement is configured to repeatedly charge at least one of the at least one electrical energy storage module. The at least one electrical energy storage module is connectable or connected to the load such that when the at least one of the at least one electrical energy storage module is discharged, an electrical pulse is created to be received by the load when the at least one electrical energy storage module is connected to the load. By repeated charging and discharging of at least one of the at least one electrical energy storage module, a plurality of successive electrical pulses are created to be received by the load when the at least one electrical energy storage module is connected to the load. The power converter arrangement comprises an input rectifier arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source. The input rectifier is a multi-phase rectifier comprising a plurality of phase legs. The phase legs are connectable or connected to respective ones of a plurality of phase conductors of the power source carrying the plurality of phases of the AC power supplied by the power source. Each phase leg comprises at least one first switch unit controllably switchable between at least a conducting state and a non-conducting state. For each phase leg, by controlling timing of switching of the at least one first switch unit of the phase leg, the drawing of current from the corresponding phase conductor of the power source can be controlled. The method 200 comprises carrying out active power factor correction, 201. The carrying out active power factor correction comprises controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source, 202.

In conclusion, an arrangement is disclosed. The arrangement comprises at least one electrical energy storage module configured such that it can be charged or discharged, the at least one electrical energy storage module being connectable or connected to a load, and a power converter arrangement connectable or connected to a power source that is supplying AC power having a plurality of phases. The power converter arrangement is configured to repeatedly charge at least one of the at least one electrical energy storage module, wherein the at least one electrical energy storage module is connectable or connected to the load such that when the at least one of the at least one electrical energy storage module is discharged, an electrical pulse is created to be received by the load when the at least one electrical energy storage module is connected to the load, wherein by repeated charging and discharging of at least one of the at least one electrical energy storage module, a plurality of successive electrical pulses are created to be received by the load when the at least one electrical energy storage module is connected to the load. The power converter arrangement comprises an input rectifier arranged to receive AC power supplied by the power source, the input rectifier being a multi-phase rectifier comprising a plurality of phase legs, the phase legs being connectable or connected to respective ones of a plurality of phase conductors of the power source carrying the plurality of phases of the AC power supplied by the power source, each phase leg comprising at least one first switch unit controllably switchable between at least a conducting state and a non-conducting state. At least one control module is configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source.

While the present invention has been illustrated in the appended drawings and the foregoing description, such illustration is to be considered illustrative or exemplifying and not restrictive; the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the appended claims, the word“comprising” does not exclude other elements or steps, and the indefinite article”a” or“an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An arrangement (100) comprising:

at least one electrical energy storage module (30; 35) configured such that it can be charged or discharged, the at least one electrical energy storage module being connectable or connected to a load (40); and

a power converter arrangement (50) connectable or connected to a power source (60) that is supplying Alternating Current, AC, power having a plurality of phases, the power converter arrangement being arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source;

the power converter arrangement being configured to repeatedly charge at least one of the at least one electrical energy storage module, wherein the at least one electrical energy storage module is connectable or connected to the load such that when the at least one of the at least one electrical energy storage module is discharged, an electrical pulse is created to be received by the load when the at least one electrical energy storage module is connected to the load, wherein by repeated charging and discharging of at least one of the at least one electrical energy storage module, a plurality of successive electrical pulses are created to be received by the load when the at least one electrical energy storage module is connected to the load;

wherein the power converter arrangement comprises an input rectifier (70) arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source, the input rectifier being a multi-phase rectifier comprising a plurality of phase legs (71, 72, 73), the phase legs being connectable or connected to respective ones of a plurality of phase conductors of the power source carrying the plurality of phases of the AC power supplied by the power source, each phase leg comprising at least one first switch unit (76; 76, 77) controllably switchable between at least a conducting state and a non-conducting state, wherein, for each phase leg, by controlling timing of switching of the at least one first switch unit of the phase leg, the drawing of current from the corresponding phase conductor of the power source can be controlled;

the arrangement further comprising:

at least one control module (80) connected to or comprised in the power converter arrangement, the at least one control module being configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source.

2. An arrangement according to claim 1, wherein the at least one control module is configured to control the timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source when the current drawn from the power source has been averaged over a plurality of cycles of the waveform of the AC voltage of the power source.

3. An arrangement according to any one of claims 1-2, wherein the power converter arrangement is connectable or connected to a power source that is supplying AC power having at least three phases, wherein the input rectifier comprises at least three phase legs, wherein the phase legs are connectable or connected to respective ones of the phase conductors of the power source carrying the phases of the AC power supplied by the power source.

4. An arrangement according to any one of claims 1-3, wherein the input rectifier is configured such that it does not require to be provided with a neutral line.

5. An arrangement according to any one of claims 1-4, wherein the input rectifier comprises or is constituted by a Vienna Rectifier (70).

6. An arrangement according to any one of claims 1-5, wherein the power converter arrangement is configured to be controllable at least with respect to a rate of charging of the at least one of the at least one electrical energy storage module, wherein the at least one control module is configured to, based on a time interval between successive discharges of the at least one of the at least one electrical energy storage module, control the rate of charging of the at least one of the at least one electrical energy storage module by the power converter arrangement such that the duration of charging of the at least one of the at least one electrical energy storage module between the successive discharges is a selected portion of the time interval between the successive discharges.

7. An arrangement according to claim 6, wherein the power converter

arrangement is configured to charge the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement, wherein the power converter arrangement is configured to be controllable with respect to at least magnitude of the charging current and/or duration of supplying of the charging current, whereby the rate of charging of the at least one of the at least one electrical energy storage module can be controlled.

8. An arrangement according to any one of claims 1-7, further comprising:

at least one second switch unit (31) controllably switchable between at least a conducting state and a non-conducting state, wherein the at least one second switch unit is connected to the power converter arrangement and to the at least one electrical energy storage module, respectively, such that the power converter arrangement charges the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement, or the at least one electrical energy storage module is discharged so as to create an electrical pulse to be received by the load, based on switching of the at least one second switch unit.

9. An arrangement according to any one of claims 1-7, further comprising:

an output rectifier (10);

wherein the input rectifier is connected to the at least one electrical energy storage module via the output rectifier, wherein the output rectifier is connected between the input rectifier and the at least one electrical energy storage module, and the at least one electrical energy storage module is connected between the output rectifier and the load, and wherein the power converter arrangement is configured to supply power to the at least one electrical energy storage module via the output rectifier.

10. An arrangement according to claim 9, further comprising:

a Direct Current (DC)-DC converter (90) connected between the input rectifier and the at least one electrical energy storage module and between the input rectifier and the output rectifier; and

at least one second switch unit (31) controllably switchable between at least a conducting state and a non-conducting state, wherein the at least one second switch unit is connected to the power converter arrangement via the output rectifier and to the at least one electrical energy storage module, respectively, such that the power converter arrangement charges the at least one electrical energy storage module by way of a charging current supplied by the power converter arrangement, or the at least one electrical energy storage module is discharged so as to create an electrical pulse to be received by the load, based on switching of the at least one second switch unit.

11. A system (100, 40) comprising:

a load (40); and an arrangement (100) according to any one of claims 1-10, wherein the at least one electrical energy storage module (30) of the arrangement is connectable or connected to the load.

12. A method (200) in an arrangement (100), the arrangement comprising:

wherein the power converter arrangement comprises an input rectifier (70) arranged to receive the AC power supplied by the power source when the power converter arrangement is connected to the power source, the input rectifier being a multi-phase rectifier comprising a plurality of phase legs (71, 72, 73), the phase legs being connectable or connected to respective ones of a plurality of phase conductors of the power source carrying the plurality of phases of the AC power supplied by the power source, each phase leg comprising at least one first switch unit controllably switchable between at least a conducting state and a non-conducting state, wherein, for each phase leg, by controlling timing of switching of the at least one first switch unit of the phase leg, the drawing of current from the corresponding phase conductor of the power source can be controlled;

the method comprising:

carrying out active power factor correction (201), comprising controlling (202) timing of switching of the at least one first switch unit of each phase leg such that the waveform of the current drawn from the power source by the input rectifier corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source.

13. A control module (80) for use in conjunction with an arrangement (100) according to any one of claims 1-10, the control module being connected to or comprised in the power converter arrangement (50) of the arrangement, the control module being configured to carry out active power factor correction by controlling timing of switching of the at least one first switch unit (76; 76, 77) of each phase leg (71, 72, 73) such that the waveform of the current drawn from the power source by the input rectifier (70) corresponds to, or comes closer to corresponding to, the waveform of the AC voltage of the power source (60). 14. A computer program product configured to, when executed in a control module

(80) according to claim 13, perform a method (200) according to claim 12.

15. A computer-readable storage medium on which there is stored a computer program product configured to, when executed in a control module (80) according to claim 13, perform a method (200) according to claim 12.