Rapid pre-charging system for active inverter

Abstract

The invention relates to a quick pre-charging system for an active inverter, which comprises three pre-charging modules respectively corresponding to each phase, each pre-charging module is arranged between an alternating current power supply and the corresponding phase of a main loop, and 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 method has the advantages of improving the pre-charging speed, reducing the energy consumption, prolonging the service life and the like.

Description

Technical Field

[0001] This invention relates to the field of active inverters, and more particularly to a fast pre-charging system for active inverters. Background Technology

[0002] Inverters require pre-charging, and traditional pre-charging solutions include... Figure 1 As shown, before the three relays K1, K2, and K3 are turned on, the main circuit needs to be pre-charged by the charging resistors RX1, RX2, and RX3 based on AC power supply 1.

[0003] However, this parallel resistor method has the problem of slow pre-charging speed, which increases the cold start time of the device. In addition, the on-time is accompanied by relatively large resistance loss and heat generation, resulting in insufficient energy consumption and lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide a fast pre-charging system for active inverters.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A fast pre-charge system for an active inverter includes three pre-charge modules corresponding to each phase. Each pre-charge module is located between the corresponding phase of the AC power supply and the main circuit. Each pre-charge module includes a relay, a first thyristor, a second thyristor, and a controller. The first and second thyristors are connected in parallel in reverse, with the negative terminal of the first thyristor connected to the AC power supply and the positive terminal connected to the main circuit.

[0007] 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 terminal of the first optocoupler is connected to both ends of the first thyristor. The positive terminal of the output terminal is connected to the first end of the eighth resistor and the base of the NPN transistor, and is connected to the positive terminal of the DC power supply through the fifth resistor. The negative terminal is connected to the second end of the eighth resistor, the emitter of the NPN transistor, and the negative terminal of the DC power supply. The positive terminal of the power input terminal of the first zero-crossing switching optocoupler is connected to the positive terminal of the DC power supply, and the negative terminal is connected to the positive terminal of the power input terminal of the second zero-crossing switching optocoupler. The negative terminal of the power input terminal of the second zero-crossing switching optocoupler is connected to the collector of the NPN transistor. The first terminal of the output terminal of the first zero-crossing switching optocoupler is connected to the control signal input terminal of the first thyristor, and the second terminal of the output terminal of the second zero-crossing switching optocoupler is connected to the control signal input terminal of the 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 terminal 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 terminal of the input of the second zero-crossing optocoupler. 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 terminal of the input end of the first zero-crossing switching optocoupler and the positive terminal of the DC power supply.

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

[0011] The controller further includes a first diode and a second diode. The negative terminal of the first diode is connected to the first terminal of the output of the first zero-crossing switching optocoupler, and the positive terminal is connected to the negative terminal of the first thyristor. The negative terminal of the second diode is connected to the second terminal of the output of the second zero-crossing switching optocoupler, and the positive terminal is connected to the positive terminal of the first thyristor.

[0012] The first diode is connected in series with a ninth resistor.

[0013] The second diode is connected in series with a tenth resistor.

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

[0015] The second terminal of the first capacitor is also connected to the second pole of the output terminal of the second zero-crossing optocoupler through a current-limiting resistor.

[0016] There are two current-limiting resistors.

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

[0018] 1. By replacing the original resistor with two thyristors, and using an optocoupler, a first zero-crossing switching optocoupler, a second zero-crossing switching optocoupler, a fifth resistor, an eighth resistor, and an NPN transistor as the conduction control for the two thyristors, conduction can be achieved at the zero-crossing point of the AC power input. On the one hand, this avoids the impact of the AC power supply on the main circuit and improves the lifespan of the main circuit. On the other hand, the pre-charging time is short and there is no heat generation, which reduces energy consumption and improves the overall lifespan.

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

[0020] 3. By setting the first diode and the second diode, rectification can be performed, thus protecting the first transistor and the second transistor.

[0021] 4. By setting the ninth and tenth resistors, signal quality can be improved and the first and second diodes can be protected. Attached Figure Description

[0022] Figure 1 This is a structural diagram of a certain existing technology;

[0023] Figure 2 This is a schematic diagram of the structure of the present invention;

[0024] Figure 3 This is a schematic diagram of the controller driver section;

[0025] Figure 4 This is a schematic diagram of the thyristor section;

[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 terminal 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. Fifth resistor, R6, Sixth resistor, R7, Seventh resistor, R8, Eighth resistor, R9, Ninth resistor, R10, Tenth resistor, R11, Eleventh resistor, R12, Twelfth resistor, R13, Thirteenth resistor, D1, First diode, D2, Second diode, C1, First capacitor, K1~K3 are relays, RX1~RX3 are charging resistors, VT1, VT3 and VT5 are first thyristors, VT2, VT4 and VT6 are second thyristors. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028] A fast pre-charge system for active inverters, such as Figure 3 As shown, it includes three pre-charging modules corresponding to each phase. Each pre-charging module is located between the corresponding phase of AC power supply 1 and main circuit 2. Since the three pre-charging modules are identical, this application only describes one pre-charging module as an example. The pre-charging 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 parallel in reverse, and the negative terminal of the first thyristor VT1 is connected to AC power supply 1, and the positive terminal is connected to main circuit 2.

[0029] like Figure 4 and Figure 3 As shown, 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 the two ends of the first thyristor VT1, and the positive terminal of its output terminal is connected to the first terminal of the eighth resistor R8 and the base of the NPN transistor Q1, and is connected to the positive terminal of the DC power supply through the fifth resistor R5. The negative terminal is connected to the second terminal of the eighth resistor R8, the emitter of the NPN transistor Q1, and the negative terminal C of the DC power supply. OM, the positive terminal of the power input of the first zero-crossing switching optocoupler IC1 is connected to the positive terminal of the DC power supply, and the negative terminal is connected to the positive terminal of the power input of the second zero-crossing switching optocoupler IC2. The negative terminal of the power input of the second zero-crossing switching optocoupler IC2 is connected to the collector of the NPN transistor Q1. The first terminal of the output of the first zero-crossing switching optocoupler IC1 is connected to the control signal input of the first thyristor VT1, and the second terminal of the output of the second zero-crossing switching optocoupler IC2 is connected to the control signal input of the second thyristor VT2.

[0030] In this embodiment, the controller 3 further includes a sixth resistor R6 and a PNP transistor Q2. One end of the sixth resistor R6 is connected to the positive terminal of the DC power supply, and the other end is connected to the emitter of the PNP transistor Q2. The base of the PNP transistor Q2 is connected to the collector of the NPN transistor Q1 and the negative terminal of the input of the second zero-crossing switching optocoupler IC2. The collector is connected to one end of the fifth resistor R5 and the base of the NPN transistor Q1. Through the sixth resistor R6 and the PNP transistor Q2, after the NPN transistor Q1 is turned on, the sixth resistor R6 and the fifth resistor R5 can be connected in parallel, thereby reducing the pull-up resistance, maintaining the continuous conduction of the NPN transistor Q1, and improving stability and reliability.

[0031] Furthermore, in actual production, Figure 3 and Figure 4 The circuits can be mounted on two separate circuit boards to avoid interference. The first connection point P1, the second connection point P2, the third connection point P3, and the fourth connection point P4 of the two circuit boards are connected to each other.

[0032] By replacing the original resistor with two thyristors, and using an optocoupler, 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 as the conduction control for the two thyristors, conduction can be achieved at the zero-crossing point of the AC power supply 1 input. On the one hand, this avoids the impact of AC power supply 1 on the main circuit 2, improving the lifespan of the main circuit 2. On the other hand, the pre-charging time is short and there is no heat generation, reducing energy consumption while improving the overall lifespan.

[0033] Generally, a second resistor R2 is provided between the positive terminal of the input of the first zero-crossing switching optocoupler IC1 and the positive terminal of the DC power supply.

[0034] In addition, controller 3 includes 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, and the fourth resistor R4 and the third resistor R3 are connected in parallel. The first terminal of the output of the first zero-crossing switching optocoupler IC1 is connected to one end of the first resistor R1, and the second terminal is connected to the other end of the first resistor R1. The first terminal of the output of the second zero-crossing switching optocoupler IC2 is connected to one end of the seventh resistor R7, and the second terminal is connected to the other end of the seventh resistor R7. The third resistor R3 and the fourth resistor R4 serve as driving resistors for the thyristors.

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

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

[0037] The controller 3 also includes a first capacitor C1 and a twelfth resistor R12. The first terminal of the first capacitor C1 is connected to the negative terminal of the first thyristor VT1 via the twelfth resistor R12, and the second terminal is connected to the positive terminal of the first thyristor VT1. The second terminal of the first capacitor C1 is also connected to the second terminal of the output of the second zero-crossing optocoupler IC2 via a current-limiting resistor. There are two current-limiting resistors: a thirteenth resistor R13 and an eleventh resistor R11 connected in series.

[0038] This application has significant advantages over existing technologies. Before the relay engages, the AC signal input from AC power supply 1 is transmitted to the two thyristors and the first optocoupler U1. When the voltage is not zero, the optocoupler conducts. At this time, the DC power input flows to the negative terminal through the fifth resistor R5 and the C and E pins of the first optocoupler U1. At this time, the NPN transistor Q1 is not conducting, and the input side of the second zero-crossing switching optocoupler IC2 is not connected. Therefore, neither the second zero-crossing switching optocoupler IC2 nor the first zero-crossing switching optocoupler IC1 has an output. At this time, the two thyristors are in the off state. Since the voltage at the non-zero point is relatively large, it can effectively protect the vulnerable components in the main circuit from the impact from AC power supply 1. Conversely, when the voltage reaches zero, the C and E pins of the first optocoupler U1 are not conducting. The voltage from the DC power supply is divided by the fifth resistor R5 and the eighth resistor R8, turning on the NPN transistor Q1. At this time, the input side of the second zero-crossing optocoupler IC2 is not connected, and the first zero-crossing optocoupler IC1 and the second zero-crossing optocoupler IC2 are turned on. The first thyristor VT1 and the second thyristor VT2 are also turned on, and pre-charging begins. In addition, due to the presence of the PNP transistor Q2, when the first zero-crossing optocoupler IC1 and the second zero-crossing optocoupler IC2 are turned on, the PNP transistor Q2 is also turned on. At this time, the fifth resistor R5 and the eighth resistor R8 are connected in parallel, which is equivalent to reducing the resistance value of the pull-up resistor and reducing the voltage drop at the base of the NPN transistor Q1, thereby further promoting the stable conduction of the NPN transistor Q1.

[0039] The pre-charge modules for the other two phases are the same as those described above, so they will not be repeated here.

[0040] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

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

2. The fast pre-charging system for an 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 terminal 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 terminal of the input of the second zero-crossing optocoupler. 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 an active inverter according to claim 1, characterized in that, A second resistor is provided between the positive terminal of the input end of the first zero-crossing switching optocoupler and the positive terminal of the DC power supply.

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

5. A fast pre-charging system for an active inverter according to claim 1, characterized in that, The controller further includes a first diode and a second diode. The negative terminal of the first diode is connected to the first terminal of the output of the first zero-crossing switching optocoupler, and the positive terminal is connected to the negative terminal of the first thyristor. The negative terminal of the second diode is connected to the second terminal of the output of the second zero-crossing switching optocoupler, and the positive terminal is connected to the positive terminal of the first thyristor.

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

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

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

9. A fast pre-charging system for an active inverter according to claim 8, characterized in that, The second terminal of the first capacitor is also connected to the second pole of the output terminal of the second zero-crossing optocoupler through a current-limiting resistor.

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

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