CN111464008A - Combined inverter - Google Patents

Abstract

The invention discloses a combined frequency converter, comprising a control module, an AC/DC circuit, a DC/DC circuit, a DC/AC circuit and a mode switch; the mode switch is connected to a power supply, the AC/DC circuit and the DC /DC circuit, the mode switch is also connected to the load, the DC/DC circuit and the DC/AC circuit; the control module controls the mode switch to turn on the power and the DC/AC circuit according to the type of the input power of the power The AC/DC circuit or the power supply and the DC/DC circuit are turned on, and the mode switch is controlled to turn on the AC/DC circuit and the load or turn on the DC/DC circuit and the load according to the type of the external load. It has the following advantages: it can be applied to AC input and DC input, can be connected to AC load and DC load, and has versatility.

Description

Combined inverter

technical field

The invention relates to a frequency converter, in particular to a combined frequency converter.

Background technique

A frequency converter is a power control device that converts a power frequency power supply into another frequency by using the on-off function of a power semiconductor device, and is widely used in all walks of life. On the one hand, the inverter itself is also an energy-consuming device; Applicable power level, so when the load power changes, it is necessary to replace the inverter or replace the power semiconductor devices inside the inverter. The replacement cost is high, and the long replacement cycle will affect the production and experiment efficiency.

SUMMARY OF THE INVENTION

The present invention provides a combined frequency converter, which overcomes the shortcomings of the frequency converter in the background art.

The adopted technical scheme that the present invention solves its technical problem is:

Combined inverter, including control module, AC/DC circuit, DC/DC circuit, DC/AC circuit and mode switch; the mode switch is connected to the power supply, AC/DC circuit and DC/DC circuit, and the mode switch is also connected to the load , DC/DC circuit and DC/AC circuit; the control module controls the mode switch according to the type of input power of the power supply to connect the power supply and AC/DC circuit or connect the power supply and DC/DC circuit, and control the mode switch according to the type of external load The switch turns on the AC/DC circuit and the load or turns on the DC/DC circuit and the load.

In one embodiment: a load front-end switch module is further included, the load front-end switch module has a plurality of load interfaces, the input terminal of the load front-end switch module is connected to the output terminal of the mode changeover switch, and the output terminal of the load front-end switch module is used to connect the load; The front-end switch module controls whether the mode conversion switch is turned on at the first moment or after the first time period according to the current of each load interface at the first moment or in the first time period after the load front-end switch module is powered through the mode conversion switch. each load interface.

In one embodiment, the mode switch includes a first control switch, the control module is electrically connected to the first control switch, and when the input power type is DC, the first control switch turns on the power supply and the DC/DC circuit, and turns off the power supply and AC/DC circuit and disconnecting AC/DC circuit and DC/DC circuit; when the input power type is AC, the first control switch turns on power supply and AC/DC circuit and turns on AC/DC circuit and DC/DC circuit , and disconnect the power supply and DC/DC circuit.

In one embodiment, the mode switch includes a second control switch, the control module is electrically connected to the second control switch, and when the external load type is DC, the second control switch turns on the DC/DC circuit and the load front-end switch module, and Disconnect the DC/AC circuit and the load front-end switch module and disconnect the DC/DC circuit and the DC/AC circuit; when the external load type is AC, the second control switch turns on the DC/AC circuit and the load front-end switch module and turns on The DC/DC circuit and the DC/AC circuit, and the DC/DC circuit and the load front-end switch module are disconnected.

In one embodiment: an AC/DC front-end switching element module, a DC/DC front-end switching element module and a DC/AC front-end switching element module are further included; the AC/DC circuit includes at least two AC/DC modules, and the AC/DC front-end switch The component module is connected to the input end of the AC/DC circuit to control the access quantity of the DC/AC module; the DC/DC circuit includes at least two DC/DC modules, and the DC/DC front-end switching component module is connected to the input end of the DC/DC circuit to Control the access quantity of the DC/DC modules; the DC/AC circuit includes at least two DC/AC modules, and the DC/AC front-end switching element module is connected to the input end of the DC/AC circuit to control the access quantity of the DC/AC modules.

In one embodiment: the AC/DC front-end switching element module controls the number of AC/DC modules connected according to the input voltage and current of the power supply and the load capacity of the AC/DC module; the DC/DC front-end switching element module is based on the input voltage and current of the power supply And the load capacity of the DC/DC module controls the access quantity of the DC/DC module; the DC/AC front-end switching element module controls the access quantity of the DC/AC module according to the power input voltage and current and the load capacity of the DC/AC module.

In one embodiment: the AC/DC module includes a rectifier bridge, which is used to rectify alternating current into direct current; the DC/DC module is used to convert a direct current with a variable voltage into a fixed voltage direct current or be used as a voltage regulator or filter; the DC The /AC module includes a PWM control chip, which is used to output a controllable alternating current according to the vector control principle; the DC/DC module and the DC/AC module are equipped with corresponding input ports, output ports and control signal ports.

In one embodiment, the control module synchronously controls at least two DC/DC modules and switches of power tubes inside the at least two DC/AC modules.

In one embodiment: the input ports of the AC/DC module, the DC/DC module and the DC/AC module include a socket end; the output end of the AC/DC module, the DC/DC module and the DC/AC module is a male end, the The end includes a protruding copper piece; the protruding copper piece is matched with the socket end so as to form a conductive plug-in structure.

In one embodiment, an auxiliary power supply module is further included, the auxiliary power supply module is connected to the power supply and the control module, and the auxiliary power supply module is used to supply power independently according to the total energy consumption of the used modules.

Compared with the background technology, the technical solution has the following advantages:

The control module controls the mode switch to switch on the power supply and AC/DC circuit or switch on the power supply and DC/DC circuit according to the type of the input power of the power supply, and control the mode switch to switch on the AC/DC circuit and the load or connect the AC/DC circuit and the load according to the type of the external load. Through DC/DC circuit and load, it can be applied to AC input and DC input, and can be connected to AC load and DC load. It has versatility and can adapt to different production and experimental needs.

The front-end switch module of the load judges whether the port has a load at the first moment or within the first period of time after the port is powered on, and closes the port that is not connected to the load to improve the safety of the inverter.

The AC/DC front-end switching element module controls the number of AC/DC modules connected according to the power input voltage and current and the load capacity of the AC/DC module. The DC/DC front-end switching element module The load capacity controls the access quantity of DC/DC modules, and the DC/AC front-end switching element module controls the access quantity of DC/AC modules according to the input voltage and current of the power supply and the load capacity of the DC/AC module, so that the inverter can be applied to a variety of Under the working condition of power level, through the automatic detection and adjustment of the switch module, the frequency converter does not need manual adjustment, and the power level can be quickly changed within the maximum power range, which greatly reduces the time used to change the power of the frequency converter and improves the production and experiment efficiency. .

The protruding copper piece and the socket end are matched to form a conductive plug-in structure. The input end of each module is the female end, that is, the socket end, and the output end is the male end, that is, the protruding copper piece, which can be directly inserted into the input end of the next module. It is convenient to replace the corresponding faulty module according to the fault of the inverter, which improves the maintenance efficiency and reduces the replacement cost.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of the principle of mode conversion of a combined inverter in a specific embodiment.

FIG. 2 is a schematic diagram of the specific principle of the combined frequency converter of the specific embodiment after the mode conversion part is omitted.

Figure 3-1 is a schematic diagram of an AC/DC module of a specific embodiment.

3-2 is a circuit diagram of an AC/DC module of a specific embodiment.

4-1 is a schematic diagram of a DC/DC module of a specific embodiment.

Figure 4-2 is a circuit diagram of a DC/DC module of a specific embodiment.

5-1 is a schematic diagram of a DC/AC module of a specific embodiment.

5-2 is a circuit diagram of the DC/AC module of the specific embodiment.

6-1 is a schematic diagram of a control module of a specific embodiment.

6-2 is a circuit diagram of the control module of the specific embodiment.

7-1 is a schematic diagram of an auxiliary power module in a specific embodiment.

7-2 is a circuit diagram of the auxiliary power module of the specific embodiment.

Detailed ways

Please refer to FIG. 1 and FIG. 2, the combined inverter includes a control module 10, an AC/DC circuit 12, a DC/DC circuit 14, a DC/AC circuit 16, and a mode switch 18; the mode switch 18 is connected to the power supply, AC/DC The DC circuit 12 and the DC/DC circuit 14, the control module 10 controls the mode changeover switch 18 to connect the power supply and the AC/DC circuit 12 or connect the power supply and the DC/DC circuit 14 according to the input type of the power supply; the mode changeover switch 18 is also connected to the load 22. The DC/DC circuit 14 and the DC/AC circuit 16 control the mode changeover switch 18 to connect the AC/DC circuit 12 and the load 22 or the DC/DC circuit 14 and the load 22 according to the type of the external load 22 .

The combined frequency converter of this specific embodiment further includes a load front-end switch module 20 , the load front-end switch module 20 has a plurality of load interfaces, the input end of the load front-end switch module 20 is connected to the output end of the mode changeover switch 18 , and the load front-end switch module 20 has multiple load interfaces. The output terminal is used to connect the load 22; the load front-end switch module 20 respectively controls the first moment or the current in the first time period after the load front-end switch module 20 is powered on through the mode switch 18 according to each load interface. Whether the mode conversion switch 18 and each load interface are turned on after the first time period.

The mode switch 18 includes a first control switch (KDC and KAC in the figure) and a second control switch (KAM and KDM in the figure), and the second control switch constitutes a connection to the mode switch 18 of the load front-end switch module 20 output. The control module 10 is electrically connected to the first control switch, and when the input power type is DC (direct current), the first control switch turns on the power supply and the DC/DC circuit 14, and disconnects the power supply and the AC/DC circuit 12 and disconnects the AC /DC circuit 12 and DC/DC circuit 14; when the input power type is AC (alternating current), the first control switch turns on the power supply and the AC/DC circuit 12 and turns on the AC/DC circuit 12 and the DC/DC circuit 14, And the power supply and DC/DC circuit 14 are disconnected. The control module 10 is electrically connected to the second control switch. When the type of the external load 22 is DC, the second control switch turns on the DC/DC circuit 14 and the load front-end switch module 20, and disconnects the DC/AC circuit 16 and the load front-end switch. module 20 and disconnects the DC/DC circuit 14 and the DC/AC circuit 16; when the type of the external load 22 is AC, the second control switch turns on the DC/AC circuit 16 and the load front-end switch module 20 and turns on the DC/DC circuit 14 and the DC/AC circuit 16, and disconnect the DC/DC circuit 14 and the load front-end switch module 20.

As shown in Figure 1, the mode is as follows: 1. The input is DC, and the output is DC. 1.1. The DC input terminals KDC and KAC are energized and closed, while the KAC of the AC input terminal and the KDC of the AC/DC output terminal are disconnected, and the power input terminal is directly input to the DC/DC circuit; 1.2. When the output terminal is connected to a DC load (such as DC Motor), the KDM and KAM of the DC output end are energized and closed, and the KDM of the DC/DC output end and the KAM of the DC/DC output end are disconnected, and the output is DC. 2. The input is DC and the output is AC. 2.1. The DC input terminals KDC and KAC are energized and closed, while the KAC of the AC input terminal and the KDC of the AC/DC output terminal are disconnected, and the input terminal is directly input to the DC/DC circuit; 2.2. When the output terminal is connected to an AC load (such as an AC motor ), the KAM at the DC/AC output end and the KDM at the DC/DC output end are energized and closed, while the KDM and KAM at the DC output end are energized and closed, and the output is AC. 3. The input is AC and the output is AC. 3.1. The KAC at the AC input end and the KDC at the AC/DC output end are energized and closed, while the DC input ends KDC and KAC are disconnected, and the input end is input to the AC/DC circuit; 3.2. When the output end is connected to an AC load (AC motor) , the KAM at the DC/AC output end and the KDM at the DC/DC output end are energized and closed, while the KDM and KAM at the DC output end are energized and closed, and the output is AC. 4. The input is DC and the output is DC. 4.1. The DC input terminals KDC and KAC are energized and closed, and the KAC of the AC input terminal and the KDC of the AC/DC output terminal are disconnected; 4.2. When the output terminal is connected to a DC load (such as a DC motor), the KDM and KAM of the DC output terminal are connected. When the electricity is closed, the KDM of the DC/DC output end and the KAM of the DC/DC output end are disconnected, and the output is DC.

Referring to FIG. 2 , the combined frequency converter of this specific embodiment further includes an AC/DC front-end switching element module 24 , a DC/DC front-end switching element module 26 and a DC/AC front-end switching element module 28 . The AC/DC circuit 12 includes at least two AC/DC modules 121 , and the AC/DC front-end switching element module 24 is connected to the input end of the AC/DC circuit 12 to control the number of DC/AC modules 121 connected. The DC/DC circuit 14 includes at least two DC/DC modules 141 , and the DC/DC front-end switching element module 26 is connected to the input end of the DC/DC circuit 14 to control the number of DC/DC modules 141 connected. The DC/AC circuit 16 includes at least two DC/AC modules 161 , and the DC/AC front-end switching element module 28 is connected to the input end of the DC/AC circuit 16 to control the access quantity of the DC/AC modules 161 .

Among the specific embodiments: the AC/DC front-end switching element module 26 controls the number of AC/DC modules connected according to the power input voltage and current and the load capacity of the AC/DC module; the DC/DC front-end switching element module is based on the power supply input voltage and The current and the load capacity of the DC/DC module control the access quantity of the DC/DC module; the DC/AC front-end switching element module controls the access quantity of the DC/AC module according to the power input voltage and current and the load capacity of the DC/AC module. Further, the control module is connected to the AC/DC front-end switching element module 24, the DC/DC front-end switching element module 26 and the DC/AC front-end switching element module 28, and is based on the power supply value and the circuit module (AC/DC, DC/DC, DC) /AC) value to generate a control command, and control each switching element module according to the command. Both DC/DC modules and DC/AC modules are equipped with corresponding input, output, and control signal ports, which can be directly connected by wires.

The DC/DC module converts the DC with a fixed voltage into a fixed voltage DC, and can also be used as a voltage regulator or filter (the DC/DC module is an isolated DC/DC, the rectifier bridge is 4 MOSFETs, and the MCU control module controls the DC When the /DC module is used, it mainly controls the switch of the rectifier bridge MOSFET, thereby adjusting the output voltage of the DC/DC output terminal); the DC/AC module includes a PWM control chip, which outputs a controllable alternating current according to the vector control principle.

In this specific implementation:

1. The parameters of each module are: AC/DC module: input 0-800VAC, maximum input current 10A; DC/DC module: input 100-600VDC, constant output 36VDC, maximum power 3.8KW; DC/AC module: input 24-420VDC , output 12-300VAC, maximum power 3.8KVA.

2. The maximum total load 19KVA inverter solution requirements are: 5 AC/DC; 5 DC/DC; 5 DC/AC; AC/DC front-end switching element module (KAD); DC/DC front-end switching element module ( KDD); DC/AC front-end switch element module (KDA); load front-end switch module (KM); MCU control module; auxiliary power supply module.

3. Initial state: all switches are closed; M1=M2=5KVA, M3=M4=M5=0KVA; switch principle analysis: a. The total load power of the inverter is 10KVA, then the input current calculated to the input terminal is 27A , Isensor=27A; b. Since the maximum input current of each AC/DC module is 10A, only 3 AC/DC modules are needed to work, KAD opens 3 AC/DC modules according to the collected Isensor, namely K1, K2, K3 Keep closed, K4 and K5 are disconnected; c. Since the maximum output power of DC/DC is 3.8KW, it needs to work 3 DC/DC modules, KDD opens 3 DC/DC modules according to the collected Isensor, namely K6, K7 , K8 is kept closed, K9 and K10 are disconnected; d. Since the maximum output power of AC/DC is 3.8KW, only 3 DC/AC modules need to be operated. KDA opens 3 DC/AC modules according to the collected Isensor, That is, K11, K12, K13 are kept closed, K14, K15 are disconnected; e, M1, M2 are loaded, KM collects current at M1, M2, K16, K17 keep, M3, M4, M5 does not collect current, so Disconnect K18, K19 and K20.

According to needs, an auxiliary power supply module is also included. The auxiliary power supply module is connected to the power supply and the control module, and the auxiliary power supply module is used to supply power to the control module independently according to the total energy consumption of the used modules.

Please refer to Figure 3-1. The AC/DC module 121 includes a rectifier bridge for rectifying alternating current into direct current. The AC/DC module 121 has five interfaces. Please refer to Figure 3-2 for the specific circuit diagram of the AC/DC module 121; Referring to Fig. 4-1, the DC/DC module 141 is used to convert the DC power with variable voltage into a fixed voltage DC power or use it as a voltage stabilizer or filter. The DC/DC module 141 has five interfaces. The DC/DC module 141 has five interfaces. Please refer to Figure 4-2 for the specific circuit diagram; please refer to Figure 5-1. The DC/AC module 161 includes a PWM control chip, which is used to output a controllable alternating current from the direct current according to the vector control principle. The DC/AC module 161 has nine interfaces, the DC Please refer to Figure 5-2 for the specific circuit diagram of the /AC module 161; please refer to Figure 6-1, the control module 10 adopts the MCU control module, for example, including the connected chips MCS912XET-256WIMAA and UCC28950, the specific circuit diagram of the control module 10, please refer to the figure 6-2; The MCU control module is equipped with an expansion interface, and the main function is to synchronously control the switch of the power tube inside the DC/DC module and the DC/AC module. The MCU control module can be programmed according to the power level and combination principle of the module, and can send synchronous PWM control signals to the power tubes in each DC/DC and DC/AC module. Please refer to Figure 7-1. The auxiliary power module includes the chip LM3478. Please refer to Figure 7-2 for the specific circuit diagram of the auxiliary power module. In this specific implementation manner: ports 1, 2, and 3 of the auxiliary power supply module are respectively connected to ports 1, 2, and 3 of the AC/DC module through the AC/DC front-end switching element module 24; ports 4 and 5 of the AC/DC module are connected through The DC/DC front-end switching element module 26 is respectively connected to the DC/DC module 1, 2 interfaces; the DC/DC module 3, 4 interfaces are respectively connected to the DC/AC module 1, 2 interfaces through the DC/AC front-end switching element module 28; DC/AC Interfaces 4, 5, and 6 of the modules are connected to the load 22 through the front-end switch module 20 of the load; P1-P5 of the control module 10 are respectively connected to the interfaces 5 and 6 of the DC/DC module and to the interfaces 7, 8 and 9 of the DC/AC module. Moreover, each of the above modules has an independent heat dissipation system, (the heat dissipation system is a mechanical heat dissipation structure, that is, a natural heat dissipation method, which is dissipated through the heat dissipation plate at the bottom of the module, and has no connection with the circuit and no control system). It has better heat dissipation.

In this specific embodiment, the DC/DC module and the DC/AC module are equipped with corresponding input ports, output ports and control signal ports, and the control signal ports are connected to the control module to control the circuit module to be turned on and off. The control module synchronously controls at least two DC/DC modules and switches of power tubes inside the at least two DC/AC modules.

The input ports of AC/DC modules, DC/DC modules and DC/AC modules include socket terminals; the output terminals of AC/DC modules, DC/DC modules and DC/AC modules are male terminals, and the male terminals include protruding copper sheets; The copper sheet and the socket end are matched to form a conductive plug-in structure.

The combined frequency converter of this specific embodiment can produce technical effects: 1. Strong applicability, the frequency converter can be combined according to various input and output types and motors of various power levels, and there is no need to purchase additional motors for individual special power levels. 2. Strong scalability, the DC/DC and DC/AC circuits can be independently used as inverters or converters; 3. Flexible control, can be adjusted according to each Programmable control of various working conditions.

The above descriptions are only preferred embodiments of the present invention, so the scope of implementation of the present invention cannot be limited accordingly, that is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the description should still be covered by the present invention. within the range.

Claims (10)

1. A combined frequency converter, characterized in that it includes a control module, an AC/DC circuit, a DC/DC circuit, a DC/AC circuit and a mode switch; the mode switch is connected to a power supply, the AC/DC circuit and all the The DC/DC circuit, the mode switch is also connected to the load, the DC/DC circuit and the DC/AC circuit; the control module controls the mode switch to turn on the power and turn on the power according to the type of the input power of the power supply. The AC/DC circuit or the power supply and the DC/DC circuit are turned on, and the mode switch is controlled to turn on the AC/DC circuit and the load or turn on the DC/DC circuit and the load according to the type of the external load . 2 . The combined frequency converter according to claim 1 , further comprising a load front-end switch module, wherein the load front-end switch module has a plurality of load interfaces, and the input end of the load front-end switch module is connected to the mode conversion. 3 . The output end of the switch, the output end of the load front-end switch module is used to connect the load; the load front-end switch module is respectively based on each of the load interfaces at the first time after the load front-end switch module is powered through the mode switch. The current at a moment or a first period of time controls whether the mode conversion switch and each load interface are turned on after the first moment or after the first period of time. 3 . The combined frequency converter according to claim 1 , wherein the mode changeover switch comprises a first control switch, the control module is electrically connected to the first control switch, and when the input power type is DC , the first control switch turns on the power supply and the DC/DC circuit, and disconnects the power supply and the AC/DC circuit and disconnects the AC/DC circuit and the DC/DC circuit; when the input power type When it is AC, the first control switch turns on the power supply and the AC/DC circuit and turns on the AC/DC circuit and the DC/DC circuit, and turns off the power supply and the DC/DC circuit. 4. The combined frequency converter according to claim 2, wherein the mode changeover switch comprises a second control switch, the control module is electrically connected with the second control switch, and when the external load type is DC , the second control switch turns on the DC/DC circuit and the load front-end switch module, disconnects the DC/AC circuit and the load front-end switch module, and disconnects the DC/DC circuit and the load front-end switch module the DC/AC circuit; when the external load type is AC, the second control switch turns on the DC/AC circuit and the load front-end switch module and turns on the DC/DC circuit and the DC/AC circuit, and disconnect the DC/DC circuit and the load front-end switch module. 5. The combined frequency converter according to claim 1, characterized in that: further comprising an AC/DC front-end switching element module, a DC/DC front-end switching element module and a DC/AC front-end switching element module; the AC/DC circuit It includes at least two AC/DC modules, and the AC/DC front-end switching element module is connected to the input end of the AC/DC circuit to control the access quantity of the DC/AC module; the DC/DC circuit includes at least two a DC/DC module, the DC/DC front-end switching element module is connected to the input end of the DC/DC circuit to control the access quantity of the DC/DC module; the DC/AC circuit includes at least two DC/DC AC module, the DC/AC front-end switching element module is connected to the input end of the DC/AC circuit to control the access quantity of the DC/AC module. 6 . The combined frequency converter according to claim 5 , wherein the AC/DC front-end switching element module controls the AC/DC module according to the power input voltage and current and the load capacity of the AC/DC module. 7 . The number of accesses of the DC/DC front-end switching element module controls the number of accesses of the DC/DC module according to the input voltage and current of the power supply and the load capacity of the DC/DC module; the DC/AC front-end switching element The module controls the access quantity of the DC/AC modules according to the input voltage and current of the power supply and the load capacity of the DC/AC modules. 7 . The combined frequency converter according to claim 5 , wherein the AC/DC module comprises a rectifier bridge for rectifying the alternating current into direct current; the DC/DC module is used for converting the direct current whose voltage is not fixed. 8 . It is converted into a fixed voltage direct current or used as a voltage stabilizer or filter; the DC/AC module includes a PWM control chip, which is used to output a controllable alternating current from the direct current according to the vector control principle; both the DC/DC module and the DC/AC module are Equipped with corresponding input port, output port and control signal port. 8 . The combined frequency converter according to claim 7 , wherein the control module synchronously controls at least two of the DC/DC modules and switches of power tubes inside the at least two DC/AC modules. 9 . 9 . The combined frequency converter according to claim 5 , wherein: the AC/DC module, the DC/DC module and the input port of the DC/AC module comprise a socket port; the AC/DC The output end of the module, the DC/DC module and the DC/AC module is a male end, and the male end includes a protruding copper sheet; the protruding copper sheet and the socket end are matched to form a conductive plug-in structure . 10. The combined frequency converter according to claim 5, characterized in that: further comprising an auxiliary power supply module, the auxiliary power supply module is connected with the power supply and the control module, and the auxiliary power supply module is used according to the used module. The total energy consumption is individually powered.

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