Fast pre-charging system for active inverter

Abstract

The utility model relates to a fast pre-charging system used for an active inverter, comprising three pre-charging modules respectively corresponding to each phase, each pre-charging module is arranged between an AC power supply and the corresponding phase of a main loop, each pre-charging module comprises a relay, a first thyristor, a second thyristor and a controller, the first thyristor and the second thyristor are reversely connected in parallel, the negative electrode of the first thyristor is connected to an alternating current power supply, the positive electrode of the first thyristor is connected to the main loop, and the controller comprises a first optocoupler, a first zero-crossing switching optical coupler, a second zero-crossing switching optical coupler, a fifth resistor, an eighth resistor and an NPN type triode. Compared with the prior art, the pre-charging circuit has the advantages of improving the pre-charging speed, reducing the energy consumption, prolonging the service life and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to active inverter field especially, it is a kind of quick precharge system for active inverter. BACKGROUND

[0002] Inverter needs precharge, traditional precharge implementation scheme as shown in Figure Figure 1 Before three relays K1, K2, K3 are turned on, need to be precharged based on ac power supply 1 to main circuit through charging resistance RX1, RX2, RX3.

[0003] However, this parallel resistance mode has the problem of slow precharge speed, increases the cold start time of device, in addition, with the problem of relatively large resistance loss and heating, leading to energy consumption and life both exist deficiency. UTILITY MODEL CONTENTS

[0004] The utility model discloses a kind of quick precharge systems for active inverter.

[0005] The utility model can be realized by the following technical solutions:

[0006] A kind of quick precharge system for active inverter, including three respectively corresponding to each phase's precharge module, each precharge module is located between ac power supply and the corresponding phase of main circuit, the precharge module includes relay, first thyristor, second thyristor and controller, the first thyristor and second thyristor are reversely connected in parallel, and the negative pole of first thyristor is connected to ac power supply, positive pole is connected to main circuit,

[0007] The controller includes first optocoupler, first zero-crossing switching optical coupler, second zero-crossing switching optical coupler, fifth resistance, eighth resistance and NPN triode, the input end of first optocoupler is respectively connected to the two ends of first thyristor, the positive pole of output end is connected to the first end of eighth resistance and the base of NPN triode, and is connected to the positive pole of direct current power supply through fifth resistance, the negative pole is connected to the second end of eighth resistance, the emitter of NPN triode and the negative pole of direct current power supply, the positive pole of power input end of first zero-crossing switching optical coupler is connected to the positive pole of direct current power supply, and the negative pole is connected to the positive pole of power input end of second zero-crossing switching optical coupler, the negative pole of power input end of second zero-crossing switching optical coupler is connected to the collector of NPN triode, the first pole of output end of first zero-crossing switching optical coupler is connected to the control signal input end of first thyristor, and the second pole of output end of second zero-crossing switching optical coupler is connected to the input end of control signal of second thyristor.

[0008] The controller also includes a sixth resistor and a PNP transistor, one end of the sixth resistor is connected to the positive electrode of the DC power supply, and the other end is connected to the emitter of the PNP transistor, the base of the PNP transistor is connected to the collector of the NPN transistor and the negative electrode of the input end of the second zero-crossing optical coupler, and the collector is connected to one end of the fifth resistor and the base of the NPN transistor.

[0009] A second resistor is provided between the positive electrode of the input end of the first zero-crossing switching optical coupler and the positive electrode of the DC power supply.

[0010] The controller also includes a first resistor, a third resistor, a fourth resistor and a seventh resistor, wherein the first resistor, the third resistor and the seventh resistor are connected in series in sequence, the fourth resistor and the third resistor are connected in parallel, and the first pole of the output end of the first zero-crossing switching optical coupler is connected to one end of the first resistor, and the second pole is connected to the other end of the first resistor, and the first pole of the output end of the second zero-crossing switching optical coupler is connected to one end of the seventh resistor, and the second pole is connected to the other end of the seventh resistor.

[0011] The controller also includes a first diode and a second diode, wherein the cathode of the first diode is connected to the first electrode of the output end of the first zero-crossing switching optocoupler, and the anode is connected to the cathode of the first thyristor, and the cathode of the second diode is connected to the second electrode of the output end of the second zero-crossing switching optocoupler, and the anode is connected to the anode of the first thyristor.

[0012] A ninth resistor is connected in series with the first diode.

[0013] A tenth resistor is connected in series with the second diode.

[0014] The controller further includes a first capacitor and a twelfth resistor. A first end of the first capacitor is connected to the negative electrode of the first thyristor via the twelfth resistor, and a second end of the first capacitor is connected to the positive electrode of the first thyristor.

[0015] The second end of the first capacitor is further connected to the second pole of the output end of the second zero-crossing switching optical coupler through a current-limiting resistor.

[0016] There are two current-limiting resistors in total.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. Two thyristors are used to replace the original resistors, and an optocoupler, a first zero-crossing switching optocoupler, a second zero-crossing switching optocoupler, a fifth resistor, an eighth resistor and an NPN transistor are used as the conduction control of the two thyristors, so that conduction can be achieved at the zero-crossing point of the AC power input. On the one hand, the impact of the AC power on the main circuit can be avoided, and the life of the main circuit can be improved. On the other hand, the pre-charging time is short and no heat is generated, which reduces energy consumption and improves the overall life.

[0019] 2. Through the sixth resistor and the PNP transistor, after the NPN transistor is turned on, the sixth resistor and the fifth resistor can be connected in parallel, thereby reducing the pull-up resistance, maintaining the continuous conduction of the NPN transistor, and improving stability and reliability.

[0020] 3. By providing the first diode and the second diode, rectification can be performed to protect the first transistor and the second transistor.

[0021] 4. By setting the ninth resistor and the tenth resistor, the signal quality can be improved and the first diode and the second diode can be protected. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a certain prior art;

[0023] Figure 2 It is a structural diagram of the utility model;

[0024] Figure 3 This is a schematic diagram of the controller drive part;

[0025] Figure 4 It is the schematic diagram of the thyristor part;

[0026] Wherein: 1, AC power supply, 2, main circuit, 3, controller, U1, first optocoupler, IC1, first zero-crossing switching optocoupler, IC2, second zero-crossing switching optocoupler, Q1, NPN transistor, Q2, PNP transistor, COM, negative pole of DC power supply, P1, first connection point, P2, second connection point, P3, third connection point, P4, fourth connection point, R1, first resistor, R2, second resistor, R3, third resistor, R4, fourth resistor, R 5. The fifth resistor, R6. The sixth resistor, R7. The seventh resistor, R8. The eighth resistor, R9. The ninth resistor, R10. The tenth resistor, R11. The eleventh resistor, R12. The twelfth resistor, R13. The thirteenth resistor, D1. The first diode, D2. The second diode, C1. The first capacitor, K1 to K3 are relays, RX1 to RX3 are charging resistors, VT1, VT3 and VT5 are first thyristors, and VT2, VT4 and VT6 are second thyristors. DETAILED DESCRIPTION

[0027] The utility model will be explained in detail below in combination with the drawings and specific embodiments. The embodiments are implemented on the premise of the technical scheme of the utility model, and detailed implementation modes and specific operation processes are given, but the protection scope of the utility model is not limited to the following embodiments.

[0028] A fast pre-charge system for an active inverter, as shown in Figure 3 each phase, and each pre-charge module is arranged between the corresponding phase of the AC power supply 1 and the main circuit 2. Since the three pre-charge modules are identical, only one of the pre-charge modules is taken as an example for description. The pre-charge module includes a relay K1, a first thyristor VT1, a second thyristor VT2, and a controller 3. The first thyristor VT1 and the second thyristor VT2 are connected in antiparallel, and the negative electrode of the first thyristor VT1 is connected to the AC power supply 1, and the positive electrode is connected to the main circuit 2.

[0029] As shown in Figure 4 and Figure 3 The controller 3 includes a first optocoupler U1, a first zero-crossing switching optocoupler IC1, a second zero-crossing switching optocoupler IC2, a fifth resistor R5, an eighth resistor R8, and an NPN transistor Q1. The input terminals of the first optocoupler U1 are connected to both ends of the first thyristor VT1, the positive electrode of the output terminal is connected to the first end of the eighth resistor R8 and the base of the NPN transistor Q1, and is connected to the positive electrode of the DC power supply through the fifth resistor R5, and the negative electrode is connected to the second end of the eighth resistor R8, the emitter of the NPN transistor Q1, and the negative electrode COM of the DC power supply. The positive electrode of the power input terminal of the first zero-crossing switching optocoupler IC1 is connected to the positive electrode of the DC power supply, the negative electrode is connected to the positive electrode of the power input terminal of the second zero-crossing switching optocoupler IC2, the negative electrode of the power input terminal of the second zero-crossing switching optocoupler IC2 is connected to the collector of the NPN transistor Q1, the first pole of the output terminal of the first zero-crossing switching optocoupler IC1 is connected to the control signal input terminal of the first thyristor VT1, and the second pole of the output terminal of the second zero-crossing switching optocoupler IC2 is connected to the control signal input terminal of the second thyristor VT2.

[0030] In the embodiment, the controller 3 further comprises a sixth resistor R6 and a PNP triode Q2, one end of the sixth resistor R6 is connected to the positive pole of the direct current power supply, the other end is connected to the emitter of the PNP triode Q2, the base of the PNP triode Q2 is connected to the collector of the NPN triode Q1 and the negative pole of the input end of the second zero-crossing switching optical coupler IC2, the collector is connected to one end of the fifth resistor R5 and the base of the NPN triode Q1. Through the sixth resistor R6 and the PNP triode Q2, the sixth resistor R6 and the fifth resistor R5 can be connected in parallel after the NPN triode Q1 is turned on, so as to reduce the pull-up resistor, maintain the continuous conduction of the NPN triode Q1, and improve the stability and reliability.

[0031] In addition, in the specific production, Figure 3 and Figure 4 The circuits of the two figures can be respectively carried on two circuit boards, so as to avoid interference, and the first connection point P1, the second connection point P2, the third connection point P3 and the fourth connection point P4 of the two figures are respectively connected.

[0032] The original resistor is replaced by two thyristors, and the light coupling, the first zero-crossing switching optical coupler IC1, the second zero-crossing switching optical coupler IC2, the fifth resistor R5, the eighth resistor R8 and the NPN triode Q1 are used as the conduction control of the two thyristors, so that the conduction at the zero-crossing point of the input of the alternating current power supply 1 can be realized. On the one hand, the impact of the alternating current power supply 1 on the main circuit 2 can be avoided, and the service life of the main circuit 2 can be improved. On the other hand, the pre-charging time is short, and there is no heating. The overall service life is improved while the energy consumption is reduced.

[0033] Generally, the positive pole of the input end of the first zero-crossing switching optical coupler IC1 is provided with a second resistor R2 between the positive pole of the direct current power supply.

[0034] In addition, the controller 3 further comprises a first resistor R1, a third resistor R3, a fourth resistor R4 and a seventh resistor R7, the first resistor R1, the third resistor R3 and the seventh resistor R7 are connected in series, the fourth resistor R4 and the third resistor R3 are connected in parallel, and the first pole of the output end of the first zero-crossing switching optical coupler IC1 is connected to one end of the first resistor R1, the second pole is connected to the other end of the first resistor R1, the first pole of the output end of the second zero-crossing switching optical coupler IC2 is connected to one end of the seventh resistor R7, and the second pole is connected to the other end of the seventh resistor R7. Among them, the third resistor R3 and the fourth resistor R4 are used as the driving resistor of the thyristor.

[0035] In addition, the controller 3 further comprises a first diode D1 and a second diode D2, the negative pole of the first diode D1 is connected to the first pole of the output end of the first zero-crossing switching optocoupler IC1, the positive pole is connected to the negative pole of the first thyristor VT1, the negative pole of the second diode D2 is connected to the second pole of the output end of the second zero-crossing switching optocoupler IC2, and the positive pole is connected to the positive pole of the first thyristor VT1, so that rectification can be performed to protect the first triode and the second triode.

[0036] In addition, the first diode D1 is connected in series with a ninth resistor R9, and the second diode D2 is connected in series with a tenth resistor R10.

[0037] The controller 3 further comprises a first capacitor C1 and a twelfth resistor R12, the first end of the first capacitor C1 is connected to the negative pole of the first thyristor VT1 through the twelfth resistor R12, and the second end is connected to the positive pole of the first thyristor VT1. The second end of the first capacitor C1 is also connected to the second pole of the output end of the second zero-crossing switching optocoupler IC2 through a current-limiting resistor. The current-limiting resistor is provided with two, which are a thirteenth resistor R13 and an eleventh resistor R11 connected in series with each other.

[0038] Compared with the prior art, the application has great advantages. Before the relay is attracted, the alternating current signal input by the alternating current power supply 1 is transmitted to the two thyristors and the first optocoupler U1. When it is not at zero point, the optocoupler is turned on. At this time, the input of the direct current power supply flows to the negative pole through the fifth resistor R5, the C pin and the E pin of the first optocoupler U1. At this time, the NPN triode Q1 is in an off state, and the input side of the second zero-crossing switching optocoupler IC2 does not form a path. Therefore, the second zero-crossing switching optocoupler IC2 and the first zero-crossing switching optocoupler IC1 have no output. At this time, the two thyristors are in an off state. Since the voltage at the non-zero point is large, the fragile elements in the main circuit can be effectively protected from the impact from the alternating current power supply 1. On the contrary, when it reaches the zero point, the C pin and the E pin of the first optocoupler U1 are not conductive, so that the voltage from the direct current power supply is divided by the fifth resistor R5 and the eighth resistor R8. The NPN triode Q1 is turned on. At this time, the input side of the second zero-crossing switching optocoupler IC2 does not form a path. The first zero-crossing switching optocoupler IC1 and the second zero-crossing switching optocoupler IC2 are turned on. The first thyristor VT1 and the second thyristor VT2 are turned on, and the pre-charging starts. In addition, due to the existence of the PNP triode Q2, when the first zero-crossing switching optocoupler IC1 and the second zero-crossing switching optocoupler IC2 are turned on, the PNP triode Q2 is also turned on. At this time, the fifth resistor R5 and the eighth resistor R8 form a parallel connection, which is equivalent to reducing the resistance value of the pull-up resistor, thereby reducing the voltage drop at the base of the NPN triode Q1, so that the stable conduction of the NPN triode Q1 can be further promoted.

[0039] The other two-phase pre-charge module is the same as the foregoing, and thus will not be described again.

[0040] The above functions, if realized in the form of software function units and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application can essentially or say the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

Claims

1. A fast pre-charging system for an active inverter, comprising three pre-charging modules corresponding to respective phases, each pre-charging module being arranged between an AC power source and a corresponding phase of a main circuit, characterized in that: The pre-charging module includes a relay, a first thyristor, a second thyristor and a controller, wherein the first thyristor and the second thyristor are connected in reverse parallel, and the negative electrode of the first thyristor is connected to the AC power supply, and the positive electrode is connected to the main circuit. The controller includes a first optocoupler, a first zero-crossing switching optocoupler, a second zero-crossing switching optocoupler, a fifth resistor, an eighth resistor, and an NPN transistor. The input end of the first optocoupler is respectively connected to the two ends of the first thyristor, the positive electrode of the output end is connected to the first end of the eighth resistor and the base of the NPN transistor, and is connected to the positive electrode of the DC power supply through the fifth resistor, and the negative electrode is connected to the second end of the eighth resistor, the emitter of the NPN transistor, and the negative electrode of the DC power supply. The positive electrode of the power input end of the first zero-crossing switching optocoupler is connected to the positive electrode of the DC power supply, and the negative electrode is connected to the positive electrode of the power input end of the second zero-crossing switching optocoupler. The negative electrode of the power input end of the second zero-crossing switching optocoupler is connected to the collector of the NPN transistor. The first electrode of the output end of the first zero-crossing switching optocoupler is connected to the control signal input end of the first thyristor, and the second electrode of the output end of the second zero-crossing switching optocoupler is connected to the control signal input end of the second thyristor.

2. A fast pre-charging system for active inverter according to claim 1, characterized in that: The controller also includes a sixth resistor and a PNP transistor, one end of the sixth resistor is connected to the positive electrode of the DC power supply, and the other end is connected to the emitter of the PNP transistor, the base of the PNP transistor is connected to the collector of the NPN transistor and the negative electrode of the input end of the second zero-crossing optical coupler, and the collector is connected to one end of the fifth resistor and the base of the NPN transistor.

3. A fast pre-charging system for active inverter according to claim 1, characterized in that: A second resistor is provided between the positive electrode of the input end of the first zero-crossing switching optical coupler and the positive electrode of the DC power supply.

4. A fast pre-charging system for active inverter according to claim 1, characterized in that: The controller also includes a first resistor, a third resistor, a fourth resistor and a seventh resistor, wherein the first resistor, the third resistor and the seventh resistor are connected in series in sequence, the fourth resistor and the third resistor are connected in parallel, and the first pole of the output end of the first zero-crossing switching optical coupler is connected to one end of the first resistor, and the second pole is connected to the other end of the first resistor, and the first pole of the output end of the second zero-crossing switching optical coupler is connected to one end of the seventh resistor, and the second pole is connected to the other end of the seventh resistor.

5. A fast pre-charging system for active inverter according to claim 1, characterized in that: The controller also includes a first diode and a second diode, wherein the cathode of the first diode is connected to the first electrode of the output end of the first zero-crossing switching optocoupler, and the anode is connected to the cathode of the first thyristor, and the cathode of the second diode is connected to the second electrode of the output end of the second zero-crossing switching optocoupler, and the anode is connected to the anode of the first thyristor.

6. A fast pre-charging system for active inverter according to claim 5, characterized in that: A ninth resistor is connected in series with the first diode.

7. A fast pre-charging system for active inverter according to claim 5, characterized in that: A tenth resistor is connected in series with the second diode.

8. A fast pre-charging system for active inverter according to claim 5, characterized in that: The controller further includes a first capacitor and a twelfth resistor. A first end of the first capacitor is connected to the negative electrode of the first thyristor via the twelfth resistor, and a second end of the first capacitor is connected to the positive electrode of the first thyristor.

9. A fast pre-charging system for active inverter according to claim 8, characterized in that: The second end of the first capacitor is further connected to the second pole of the output end of the second zero-crossing switching optical coupler through a current-limiting resistor.

10. A fast pre-charging system for active inverter according to claim 9, characterized in that: There are two current-limiting resistors in total.

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