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WO2000059101A1 - Procede et appareil destine a commander un appareil a modulation d'impulsion en duree - Google Patents

Procede et appareil destine a commander un appareil a modulation d'impulsion en duree Download PDF

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Publication number
WO2000059101A1
WO2000059101A1 PCT/US2000/008251 US0008251W WO0059101A1 WO 2000059101 A1 WO2000059101 A1 WO 2000059101A1 US 0008251 W US0008251 W US 0008251W WO 0059101 A1 WO0059101 A1 WO 0059101A1
Authority
WO
WIPO (PCT)
Prior art keywords
switching circuit
pulse width
inverter
sensor
width modulated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2000/008251
Other languages
English (en)
Inventor
Zahid Ansari
Bruce L. Prickett
Jonathan Andrew Guy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ANACON SYSTEMS Inc
Original Assignee
ANACON SYSTEMS Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ANACON SYSTEMS Inc filed Critical ANACON SYSTEMS Inc
Priority to HK02104878.7A priority Critical patent/HK1045221A1/zh
Priority to EP00918477A priority patent/EP1173921A4/fr
Priority to AU39278/00A priority patent/AU3927800A/en
Priority to CA002380688A priority patent/CA2380688A1/fr
Publication of WO2000059101A1 publication Critical patent/WO2000059101A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC
    • H02M5/42—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters
    • H02M5/44—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC
    • H02M5/453—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current

Definitions

  • This invention relates generally to power supply circuits. More particularly, this invention relates to sensor systems used to control pulse width modulated output signals.
  • PWM Pulse Width Modulation
  • inverter switches As an example, a typical PWM power supply is configured using an H-bridge inverter switching circuit made of insulated gate bipolar transistors (IGBT's). These IGBT's are controlled so as to pulse a voltage across a load. The magnitude of the output voltage is generally maintained constant, while the width of the pulse varies.
  • IGBT's insulated gate bipolar transistors
  • the PWM waveform can be used to simulate a sine wave output voltage of a desired magnitude and frequency, including very low frequencies.
  • a variable speed motor controller can be implemented for an induction motor through the use of PWM.
  • a sensor In order to control an electrical characteristic of a circuit or load being powered, a sensor is typically used to sense an electrical characteristic associated with the circuit or load. For example, a measurement of motor current can be used to determine the speed at which a known motor is operating. Then, this measurement can be used to provide feedback to the motor speed controller which adjusts the PWM scheme to control the speed of the motor.
  • the filtering technique has involved use of a traditional analog low pass filter or a digital filter coupled to the electrical signal being sensed, e.g., filtering of a voltage signal.
  • These filters typically require a long time constant in order to accomplish the level of attenuation required for the worst transients.
  • the response time to respond to an overcurrent condition can result in damage to circuit elements. For example, in the case of IGBT's, a large overcurrent for more than 10 microseconds can cause damage to these switching transistors. Similarly, an overcurrent can damage a load if not corrected quickly.
  • the filtering actually inhibits the protection of the power supply circuitry. Therefore, there is a need for a sensor system that is not affected by transients, yet, does not allow the rest of the circuit to be damaged.
  • Sampling is another technique that has been implemented in an attempt to avoid the problems caused by transients.
  • the electrical characteristic is sampled for a short period within each output cycle.
  • a sample and hold technique is used to accomplish this.
  • this method cannot protect the circuit from abnormal behavior during the remainder of the cycle. For example, an overcurrent condition could go undetected and a motor could be damaged before the overcurrent is detected by the sample and hold circuit. Thus, sampling has failed to adequately address the problem as well.
  • the present invention overcomes disadvantages of earlier sensing system designs and provides inventive subject matter which satisfies needs left unfulfilled by the current state of the art.
  • One embodiment of the invention is advantageous in that it allows sensing to occur for a substantial portion of a cycle while still avoiding the effects of transient conditions. Another embodiment is advantageous in that it removes the sensor from the circuit before a transient condition can cause problems, thus protecting the sensor from damage and avoiding an inaccurate result produced by the transient. Another advantage offered by one embodiment of the invention is that it protects circuitry by monitoring for an extended period of time during an output waveform.
  • a system having an input to receive a DC voltage signal; a first switching circuit, such as an inverter circuit, is electrically coupled to the input and to an output; a sensor is coupled to the first switching circuit so as to sense a signal; a second switching circuit is coupled with the first switching circuit and the sensor so as to disconnect the sensor from the first switching circuit in order to avoid a transient.
  • a variety of switching systems are provided which can be implemented to disconnect the sensor from the first switching circuit, e.g., from the inverter circuit.
  • a set of at least two switches configured in series can be used with different control signals opening each control signal's respective switch during a known transient causing event, e.g., the switching of an inverter switch.
  • each control signal closes a switch during a portion of a half cycle and opens the switch upon the known occurrence of a transient causing event.
  • a single switch could be used in which a single control signal is activated at least twice during an output signal cycle to open the switch during a known transient causing event, such as the switching of inverter switches which are known to cause transients.
  • Figure 1 shows a circuit in which a sensor is electrically coupled to an inverter circuit by a switching circuit that is configured to disconnect the sensor from the inverter switching circuit.
  • Figure 2 shows an alternative switching circuit that could be used in place of the switching circuit in Figure 1.
  • Figure 3 shows another alternative switching circuit that could be used in place of the switching circuits of Figures 1 and 2.
  • Figure 4 shows a flow diagram that illustrates the method of operation for decoupling the sensor from the inverter circuit.
  • Figure 5 shows a typical bipolar PWM waveform implemented by many power sources.
  • Figure 6 shows a unipolar PWM waveform implemented by other power sources.
  • Circuit 100 comprises a circuit to provide a DC voltage as an input to a switching circuit 112.
  • the switching circuit 112 is controlled by a controller 116 to provide an output to a load.
  • a transducer such as Rsens, is used to transduce an electrical characteristic of the circuit or load 138 to a signal.
  • a sensor gathers the signal associated with the transducer for further processing.
  • a switching circuit 120 is shown in Figure 1 to electrically couple/decouple the sensor to and from the switching circuit 112.
  • FIG. 1 A more detailed look at the circuit in Figure 1 shows an AC power source 130 coupled to an AC to DC converter 134, such as a full bridge rectifier having a ripple smoothing filter.
  • the AC/DC converter outputs a DC waveform to an input 104 of a switching circuit 112.
  • a DC waveform is not intended to be limited to a strictly constant voltage; rather, waveforms having a ripple, such as those produced by conventional AC/DC converters would be included in the definition as well.
  • the DC signal in Figure 1 is shown electrically coupled to an input 104 of the switching circuit 112.
  • the switching circuit 112 is preferably a full bridge inverter switching circuit commonly referred to as an H-bridge. As shown in Figure 1, this switching circuit is comprised of four switches that are controlled by control signals from a controller.
  • the controller is microcontroller 116.
  • This microcontroller is preferably programmed with a pulse width modulation (PWM) program that provides control signals for the four switches. By using power transistors for the four switches, the switches can be placed in conducting or non-conducting states by these control signals from the microcontroller outputs.
  • PWM pulse width modulation
  • a variety of pulse width modulation schemes are currently in use. These schemes are also used to supply power to a variety of different loads.
  • Figure 5 shows a bipolar pulse width modulation voltage waveform which transitions between -Vdc and +Vdc.
  • Figure 6 shows a unipolar pulse width modulation waveform.
  • the unipolar PWM voltage signal oscillates between the ground reference voltage and +Vdc or between the ground reference voltage and -Vdc.
  • the pulse width signals can be manipulated so as to have an effective voltage signal, e.g., a sine wave, a sawtooth wave, etc.
  • PWM output signals are used to approximate a sine wave.
  • a PWM scheme can be used to manipulate the frequency and magnitude of the equivalent sine wave by varying the pulse widths and pulse spacings of the pulse width modulation output signal used to power a motor.
  • transients sometimes will be generated when these switches, for example, transition from a conducting state to a non-conducting state, as such transitions are associated with a transition in the pulse width modulated output signal.
  • Transients are especially a problem in the generation of a bipolar pulse width modulation signal, because each output voltage transition in the bipolar scheme involves a zero crossing by the voltage signal and a consequent current spike associated with the zero crossing for inductive loads.
  • known conditions associated with a specific load also can result in the predictable occurrence of electrical transients.
  • the sensing equipment used to monitor the circuit not be significantly affected by these transients. At the same time, however, it is important to sense for as long as possible so as to gain the most benefit from the sensing.
  • the current in a motor load during operation is often monitored so as to prevent overload currents and/or measure the speed of the motor. By continuously monitoring the current of the motor, an overload condition can be detected at the earliest possible point in time.
  • feedback can be provided to adjust a PWM output signal, for example, so as to adjust the speed of the motor.
  • the PWM signal can be shut off if a motor overload current is detected. The monitoring is therefore most useful when the electrical characteristic can be monitored for the most time possible.
  • FIG. 1 shows a sense resistor "Rsens" through which the current flowing through the motor can be derived.
  • a microcontroller 116 receives an input signal of the voltage across the known resistor value Rsens. Therefore, it can determine the load current. This is merely one scheme for sensing an electrical condition. Other transducers could be used to provide an input signal to the processor and to represent other electrical characteristics, as would be understood by those of ordinary skill in the art.
  • the microcontroller processes the received voltage signal; for example it can utilize the voltage as a data value in a speed control program. Also, it can act as a continuous comparator to process the sensed signal. In this way feedback could be provided for control of the output signal. Furthermore, the value can be utilized to detect an overload condition. While this configuration would be sufficient for normal operating conditions, a transient could cause the sensor to erroneously respond to the transient signal.
  • switching circuit 120 provides two switches electrically coupled in series between the sensor and the inverter switching circuit 112.
  • the switches When the switches are in a conducting state, the sensor is electrically coupled to the inverter.
  • the switches S5 and S6 are transistors that are controlled by signals from the microcontroller 116.
  • the microcontroller can open either switch S5 to avoid the harmful effects of any subsequent transient. During such time, the microcontroller can disregard the input signal received by the sensor.
  • switch S5 can again be signalled to go back to a conducting state and the sensor can resume sensing.
  • switch S6 can be signalled to enter a non-conducting state and the sensing operation can be discontinued until the harmful transient effect diminishes. In this way, the effect of a harmful transient is avoided, while the sensor is allowed to continuously operate for a substantial portion of each PWM half cycle.
  • Two switches are provided in switching circuit 120 to correspond to the two voltage transitions that occur in a pulse width modulation cycle. Thus, each switch can be controlled by a separate control signal.
  • FIG. 2 shows an alternative switching circuit 220 that could be used in place of switching circuit 120 in Figure 1.
  • Switching circuit 220 uses two switches electrically coupled in parallel between the sensor 216 and the inverter switching circuit.
  • the microcontroller sends control signals to switches S7 and S8 so that at least one of the switches, preferably transistors, is conducting during normal operation.
  • the microcontroller can switch the conducting switch to a non-conducting state with a first control signal.
  • the other switch could be closed with a different control signal for the remaining normal operation of the cycle.
  • the second switch could be opened immediately prior to a transition of the PWM cycle.
  • FIG. 3 shows yet another embodiment of a switching circuit.
  • Switching circuit 320 can be pulsed by a single control signal twice during each PWM cycle to open the switch and disconnect the sensor from the inverter circuit.
  • the gate of an NMOS transitor can simply be pulsed low by the microcontroller when a transition is about to occur.
  • the senor could be removed for the entire time period that a transient exists, one might choose to couple the sensor to the switching circuit, e.g., the inverter switching circuit, when the transient condition does not present a problem to the sensor.
  • the sensor does not have to be decoupled from the inverter for the entire occurrence of the transient.
  • the sensor could be coupled to the switching circuit at either or both the beginning and end of a transient and decoupled during the harmful portion of the transient. In this way, the sensor would effectively be decoupled during the transient.
  • the various switching circuits could be employed to electrically decouple the sensor, immediately prior to until immediately after a known transient occurrence or switch transition occurrence, so as to avoid the inherent problems with conventional sample and hold techniques .
  • FIG. 4 shows that an input voltage signal is received 404.
  • the inverter switching circuit is utilized to produce an output signal 408.
  • the output signal is output to the load to power the load 412.
  • a sensor is electrically coupled to the inverter switching circuit 416. And, the sensor is decoupled from the inverter switching circuit to avoid transients 420, as explained above.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)

Abstract

L'invention concerne un système de détecteur à modulation d'impulsions en durée, dans lequel un détecteur (116) peut être découplé du circuit de façon à éviter les transitoires. Un circuit de commutation (120) peut être couplé entre le détecteur et le circuit (112) convertisseur de commutation à modulation d'impulsions en durée, et exploité avant que ne survienne une transition de commutation du circuit convertisseur de commutation. La période de détection est cependant mise en application, de préférence, pendant une partie importante de la période de façon à être plus efficace que les techniques habituelles d'échantillonage et de blocage.
PCT/US2000/008251 1999-03-29 2000-03-28 Procede et appareil destine a commander un appareil a modulation d'impulsion en duree Ceased WO2000059101A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
HK02104878.7A HK1045221A1 (zh) 1999-03-29 2000-03-28 用於控制脉冲宽度调谐装置的方法和设备
EP00918477A EP1173921A4 (fr) 1999-03-29 2000-03-28 Procede et appareil destine a commander un appareil a modulation d'impulsion en duree
AU39278/00A AU3927800A (en) 1999-03-29 2000-03-28 Method and apparatus for controlling pulse width modulation device
CA002380688A CA2380688A1 (fr) 1999-03-29 2000-03-28 Procede et appareil destine a commander un appareil a modulation d'impulsion en duree

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US12677199P 1999-03-29 1999-03-29
US60/126,771 1999-03-29
US16432699P 1999-11-07 1999-11-07
US60/164,326 1999-11-07

Publications (1)

Publication Number Publication Date
WO2000059101A1 true WO2000059101A1 (fr) 2000-10-05

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PCT/US2000/008251 Ceased WO2000059101A1 (fr) 1999-03-29 2000-03-28 Procede et appareil destine a commander un appareil a modulation d'impulsion en duree

Country Status (5)

Country Link
EP (1) EP1173921A4 (fr)
AU (1) AU3927800A (fr)
CA (1) CA2380688A1 (fr)
HK (1) HK1045221A1 (fr)
WO (1) WO2000059101A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003087855A1 (fr) * 2002-04-17 2003-10-23 Danfoss Drives A/S Procede de mesure de courants dans un controleur de moteur et controleur de moteur utilisant ce procede
US20110227632A1 (en) * 2008-11-24 2011-09-22 Lotto Christian Charge pulse detecting circuit

Citations (3)

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Publication number Priority date Publication date Assignee Title
US5373195A (en) * 1992-12-23 1994-12-13 General Electric Company Technique for decoupling the energy storage system voltage from the DC link voltage in AC electric drive systems
US5710699A (en) * 1996-05-28 1998-01-20 General Electric Company Power electronic interface circuits for batteries and ultracapacitors in electric vehicles and battery storage systems
US6031738A (en) * 1998-06-16 2000-02-29 Wisconsin Alumni Research Foundation DC bus voltage balancing and control in multilevel inverters

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US3541319A (en) * 1967-12-21 1970-11-17 Bendix Corp Apparatus having infinite memory for synchronizing an input signal to the output of an analog integrator
US4924158A (en) * 1989-04-03 1990-05-08 General Motors Corporation Motor driver protection circuit
EP0529366B1 (fr) * 1991-08-28 1995-04-12 Siemens Aktiengesellschaft Convertisseur à découpage avec capteur de courant
US5204594A (en) * 1991-10-03 1993-04-20 Sgs-Thomson Microelectronics, Inc. Circuit for providing a signal proportional to the average current flowing through coils of a motor operated in both linear and PWM modes
EP0744823B1 (fr) * 1995-05-23 1999-01-07 STMicroelectronics S.r.l. Masquage de bruit de commutation dans la commande d'un pont de type "H"

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5373195A (en) * 1992-12-23 1994-12-13 General Electric Company Technique for decoupling the energy storage system voltage from the DC link voltage in AC electric drive systems
US5710699A (en) * 1996-05-28 1998-01-20 General Electric Company Power electronic interface circuits for batteries and ultracapacitors in electric vehicles and battery storage systems
US6031738A (en) * 1998-06-16 2000-02-29 Wisconsin Alumni Research Foundation DC bus voltage balancing and control in multilevel inverters

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1173921A4 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003087855A1 (fr) * 2002-04-17 2003-10-23 Danfoss Drives A/S Procede de mesure de courants dans un controleur de moteur et controleur de moteur utilisant ce procede
GB2402225A (en) * 2002-04-17 2004-12-01 Danfoss Drives As Method for measuring currents in a motor controller and motor controller using such method
US20110227632A1 (en) * 2008-11-24 2011-09-22 Lotto Christian Charge pulse detecting circuit
US8760147B2 (en) * 2008-11-24 2014-06-24 Csem Centre Suisse D'electronique Et De Microtechnique Sa—Recherche Et Developpement Charge pulse detecting circuit

Also Published As

Publication number Publication date
EP1173921A4 (fr) 2004-10-06
HK1045221A1 (zh) 2002-11-15
AU3927800A (en) 2000-10-16
EP1173921A1 (fr) 2002-01-23
CA2380688A1 (fr) 2000-10-05

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