Parallel current sharing device based on parameter characteristics of IGBT (Insulated Gate Bipolar Translator)

Abstract

The utility model belongs to the technical field of IGBTs (Insulated Gate Bipolar Transistors), and relates to a parallel current sharing device based on parameter characteristics of an IGBT, which comprises a first IGBT board and a second IGBT board, the second IGBT board is connected with the first IGBT board in parallel, the first IGBT board comprises a first six-tube parallel current magnetic coupling device, the second IGBT board comprises a second six-tube parallel current magnetic coupling device, and the first six-tube parallel current magnetic coupling device is connected with the second IGBT board. The first six-tube parallel current magnetic coupling device and the second six-tube parallel current magnetic coupling device are arranged in the same way. IGBT parallel instantaneous current sharing is realized by utilizing the characteristics of the IGBTs and magnetic clamping, the capacity of a single machine can be improved, and the power density of the whole machine can be improved; in addition, the stacked structure of the plurality of IGBT single plates can be reasonably controlled, a cooling fan with a larger size specification can be selected, and the cooling fan with the larger size specification can easily improve the air volume, so that the heat dissipation capability of the whole machine is further ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of IGBT, and more specifically to a parallel current balancing device based on the parameter characteristics of the IGBT itself. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor) is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar IGBT) and MOS (insulated gate field effect transistor). It has the advantages of high input impedance of MOSFET and low on-state voltage drop of GTR. IGBT is widely used in the design of static VAR compensator (SVG) products. With the development of power grid in recent years, the power grid has put forward higher requirements for reactive energy compensation. If you want to increase the single-unit capacity of SVG while controlling the cost, you need to use the IGBT multi-tube parallel solution. There is a technical problem that needs to be solved when using the IGBT multi-tube parallel solution, that is, the IGBT current sharing problem.

[0003] The manufacturing of IGBTs, the manufacture of PCBs, and the aging of modules during operation will change the parameters of the IGBT circuit, resulting in inconsistencies in the internal and external parameters of each IGBT, making it impossible for the IGBTs running in parallel to be turned on or off at the same moment, that is, among the multiple tubes in parallel, there will always be one tube that is turned on first or turned off last. After a lot of tests, it was found that if the circuit parameters are strictly controlled, the time difference between the tubes turning on or off is at the nanosecond level. Utility Model Content

[0004] In view of the above-mentioned defects of the prior art, the utility model provides a parallel current balancing device based on the parameter characteristics of the IGBT itself, comprising:

[0005] A first IGBT board, a second IGBT board, the second IGBT board is connected in parallel with the first IGBT board, the first IGBT board includes a first six-tube parallel current magnetic coupling device, the second IGBT board includes a second six-tube parallel current magnetic coupling device, and the first six-tube parallel current magnetic coupling device and the second six-tube parallel current magnetic coupling device are configured the same.

[0006] Preferably, the first six-tube parallel current magnetic coupling device comprises:

[0007] The collector of IGBT Q41 is respectively connected to the anode of diode D41, the collector of IGBT Q42, the anode of diode D42, the collector of IGBT Q43, the anode of diode D43, and one end of capacitor C21; the emitter of IGBT Q41 is respectively connected to the cathode of diode D41, the anode of diode D16, the collector of IGBT Q31, and the anode of diode D31.

[0008] Preferably, the first six-tube parallel current magnetic coupling device further comprises:

[0009] The emitter of IGBT Q31 is connected to the cathode of diode D31, the anode of diode D21, the collector of IGBT Q21, the anode of diode D22, the collector of IGBT Q22, and the anode of diode D23, respectively; the collector of IGBT Q23, the emitter of IGBT Q32, the cathode of diode D32, the emitter of IGBT Q33, and the cathode of diode D33 are connected.

[0010] Preferably, the first six-tube parallel current magnetic coupling device further comprises:

[0011] The emitter of IGBT Q21 is connected to the anode of diode D11 and the collector of IGBT Q11, respectively. The cathode of diode D21 is connected to the cathode of diode D15. The emitter of IGBT Q42 is connected to the cathode of diode D42, the collector of IGBT Q32 and the anode of diode D32, respectively.

[0012] Preferably, the first six-tube parallel current magnetic coupling device further comprises:

[0013] The emitter of IGBT Q43 is respectively connected to the cathode of diode D43, the collector of IGBT Q33, and the anode of diode D33; the other end of capacitor C21 is respectively connected to the cathode of diode D16, the anode of diode D15, and one end of capacitor C11; the other end of capacitor C11 is respectively connected to the emitter of IGBT Q11, the cathode of diode D11, the emitter of IGBT Q12, the cathode of diode D12, the emitter of IGBT Q13, and the cathode of diode D13.

[0014] Preferably, the second six-tube parallel current magnetic coupling device comprises:

[0015] The collector of IGBT Q46 is respectively connected to the anode of diode D46, the collector of IGBT Q45, the anode of diode D45, the collector of IGBT Q44, the anode of diode D44, and one end of capacitor C22; the emitter of IGBT Q46 is respectively connected to the cathode of diode D46, the anode of diode D26, the collector of IGBT Q36, and the anode of diode D36.

[0016] Preferably, the second six-tube parallel current magnetic coupling device further comprises:

[0017] The emitter of IGBT Q36 is connected to the cathode of diode D36, the anode of diode D26, the collector of IGBT Q26, the anode of diode D25, the collector of IGBT Q25, and the anode of diode D24, respectively; the collector of IGBT Q24, the emitter of IGBT Q35, the cathode of diode D35, the emitter of IGBT Q34, and the cathode of diode D34 are connected.

[0018] Preferably, the second six-tube parallel current magnetic coupling device further comprises:

[0019] The emitter of IGBT Q26 is connected to the anode of diode D16 and the collector of IGBT Q16, respectively. The cathode of diode D26 is connected to the cathode of diode D25. The emitter of IGBT Q45 is connected to the cathode of diode D45, the collector of IGBT Q35 and the anode of diode D35, respectively.

[0020] The emitter of IGBT Q44 is respectively connected to the cathode of diode D44, the collector of IGBT Q34, and the anode of diode D34; the other end of capacitor C22 is respectively connected to the cathode of diode D26, the anode of diode D25, and one end of capacitor C21; the other end of capacitor C21 is respectively connected to the emitter of IGBT Q16, the cathode of diode D16, the emitter of IGBT Q15, the cathode of diode D15, the emitter of IGBT Q16, and the cathode of diode D14.

[0021] Preferably, a transformer T1 is connected between the second IGBT board and the first IGBT board.

[0022] Preferably, the number of the first IGBT boards is 2 to the power of n, the number of the second IGBT boards is 2 to the power of n, and n is a natural number greater than or equal to 2.

[0023] The implementation of the parallel current balancing device based on the IGBT's own parameter characteristics of the utility model has the following beneficial effects: by setting a first IGBT board and a second IGBT board, the second IGBT board is connected in parallel with the first IGBT board, the first IGBT board includes a first six-tube parallel current magnetic coupling device, the second IGBT board includes a second six-tube parallel current magnetic coupling device, and the first six-tube parallel current magnetic coupling device and the second six-tube parallel current magnetic coupling device are configured the same; the IGBT's own characteristics and magnetic clamping are utilized to achieve instantaneous current balancing of the IGBT in parallel, that is, utilizing Magnetic clamping limits the current that each PCB needs to withstand. At the moment of switching on or off, the IGBT can withstand a certain pulse current within nanoseconds. When multiple tubes are connected in parallel, although there is always one tube that is turned on first or turned off last, as long as the pulse current on each PCB is limited, the current equalization at the moment of switching can be achieved, and the capacity of a single machine and the power density of the whole machine can be increased. The structure of stacking multiple IGBT boards can also be reasonably controlled, and a cooling fan of larger size can be selected. A cooling fan of large size can easily increase the air volume, which further ensures the heat dissipation capacity of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. The utility model will be further described below in combination with the drawings and embodiments. In the drawings:

[0025] Figure 1 It is a structural schematic diagram of a parallel current-sharing device based on the parameter characteristics of IGBT itself in the utility model;

[0026] Figure 2 It is a schematic diagram of a type I three-level inverter in the prior art. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0029] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0030] See also Figure 1 , is a schematic diagram of the structure of the parallel current balancing device based on the IGBT's own parameter characteristics. Figure 1 As shown, in the parallel current equalization device based on the IGBT's own parameter characteristics provided in the first embodiment of the utility model, at least a first IGBT board and a second IGBT board are included, the second IGBT board is connected in parallel with the first IGBT board, the first IGBT board includes a first six-tube parallel current magnetic coupling device, the second IGBT board includes a second six-tube parallel current magnetic coupling device, and the first six-tube parallel current magnetic coupling device and the second six-tube parallel current magnetic coupling device are configured the same.

[0031] The first six-tube parallel current magnetic coupling device comprises:

[0032] The collector of IGBT Q41 is respectively connected to the anode of diode D41, the collector of IGBT Q42, the anode of diode D42, the collector of IGBT Q43, the anode of diode D43, and one end of capacitor C21; the emitter of IGBT Q41 is respectively connected to the cathode of diode D41, the anode of diode D16, the collector of IGBT Q31, and the anode of diode D31;

[0033] The emitter of IGBT Q31 is connected to the cathode of diode D31, the anode of diode D21, the collector of IGBT Q21, the anode of diode D22, the collector of IGBT Q22, and the anode of diode D23, respectively; the collector of IGBT Q23, the emitter of IGBT Q32, the cathode of diode D32, the emitter of IGBT Q33, and the cathode of diode D33 are connected;

[0034] The emitter of IGBT Q21 is connected to the anode of diode D11 and the collector of IGBT Q11, respectively. The cathode of diode D21 is connected to the cathode of diode D15. The emitter of IGBT Q42 is connected to the cathode of diode D42, the collector of IGBT Q32 and the anode of diode D32, respectively.

[0035] The emitter of IGBT Q43 is respectively connected to the cathode of diode D43, the collector of IGBT Q33, and the anode of diode D33; the other end of capacitor C21 is respectively connected to the cathode of diode D16, the anode of diode D15, and one end of capacitor C11; the other end of capacitor C11 is respectively connected to the emitter of IGBT Q11, the cathode of diode D11, the emitter of IGBT Q12, the cathode of diode D12, the emitter of IGBT Q13, and the cathode of diode D13.

[0036] The second six-tube parallel current magnetic coupling device comprises:

[0037] The collector of IGBT Q46 is respectively connected to the anode of diode D46, the collector of IGBT Q45, the anode of diode D45, the collector of IGBT Q44, the anode of diode D44, and one end of capacitor C22; the emitter of IGBT Q46 is respectively connected to the cathode of diode D46, the anode of diode D26, the collector of IGBT Q36, and the anode of diode D36;

[0038] The emitter of IGBT Q36 is connected to the cathode of diode D36, the anode of diode D26, the collector of IGBT Q26, the anode of diode D25, the collector of IGBT Q25, and the anode of diode D24, and the collector of IGBT Q24, the emitter of IGBT Q35, the cathode of diode D35, the emitter of IGBT Q34, and the cathode of diode D34 are connected respectively;

[0039] The emitter of IGBT Q26 is connected to the anode of diode D16 and the collector of IGBT Q16, respectively. The cathode of diode D26 is connected to the cathode of diode D25. The emitter of IGBT Q45 is connected to the cathode of diode D45, the collector of IGBT Q35 and the anode of diode D35, respectively.

[0040] The emitter of IGBT Q44 is respectively connected to the cathode of diode D44, the collector of IGBT Q34, and the anode of diode D34; the other end of capacitor C22 is respectively connected to the cathode of diode D26, the anode of diode D25, and one end of capacitor C21; the other end of capacitor C21 is respectively connected to the emitter of IGBT Q16, the cathode of diode D16, the emitter of IGBT Q15, the cathode of diode D15, the emitter of IGBT Q16, and the cathode of diode D14.

[0041] The transformer T1 is connected between the second IGBT board and the first IGBT board. The anode of the diode D21, the collector of the IGBT Q21, the anode of the diode D22, the collector of the IGBT Q22, and the anode of the diode D23 are connected, and the collector of the IGBT Q23 is connected to the pin 1 of the transformer T1. The anode of the diode D24 is connected, and the collector of the IGBT Q24, the emitter of the IGBT Q35, the cathode of the diode D35, the emitter of the IGBT Q34, and the cathode of the diode D34 are connected to the pin 2 of the transformer T1.

[0042] Figure 2 Schematic diagram of a type I three-level inverter in the prior art. Figure 2 Most of the previous means shown are intended to ensure dynamic current sharing of the IGBT during the operation of the IGBT.

[0043] This embodiment mainly focuses on the transient state of turning on and off of IGBTs in parallel operation, and proposes a transient current sharing solution for multiple IGBTs in parallel. The reason is:

[0044] First, during the IGBT's turn-on process, due to the different parasitic RC parameters of the gate, the time it takes for each IGBT to charge to the threshold voltage and turn on is also different. This will cause the first IGBT to be turned on in parallel to bear the entire current at the moment of turning on. It is conceivable that if this current exceeds the range that the IGBT can withstand, it will cause the IGBT to blow up, and the remaining tubes will also blow up one after another because they cannot withstand the overload current, eventually leading to the collapse of the entire system;

[0045] Secondly, during the IGBT shutdown process, due to the different parasitic RC parameters of the gate and the voltage oscillation caused by the parasitic inductance of the emitter pin, the gate of each IGBT discharges to the threshold voltage and shuts down at different times. This will cause the last IGBT to shut down among multiple IGBTs running in parallel to bear the entire current at the moment of shutdown. As can be seen from the previous analysis, this also has the risk of causing system crashes.

[0046] Taking the commonly used 650V75A rated IGBT as an example (hereinafter all examples are based on IGBTs of this specification), it can be seen from the specification that the pulse current that the collector of most IGBTs of this specification on the market can withstand is 300A. Figure 1 Among the three IGBTs running in parallel on each PCB board shown, due to the different parasitic RC parameters in the circuit and the oscillation of the emitter pin, at the moment of turning on or off, the IGBT that is turned on first only needs to withstand a pulse current of 225A. This pulse current is at the ns level, which is completely tolerable for the IGBT. This embodiment well solves the problem of transient current sharing when multiple IGBTs are connected in parallel at the moment of turning on and off in practical applications.

[0047] In some optional implementations of this embodiment, the number of the first IGBT boards may be 2 to the power of n, and accordingly, the number of the second IGBT boards may also be 2 to the power of n, where n is a natural number greater than or equal to 2. In other words, 4 boards, 8 boards, or 16 boards may be connected in parallel, etc. The corresponding single-machine peak current may be 900A, 1800A, 3600A, etc. This is of great significance in terms of increasing the capacity of a single machine and the power density of the entire machine.

[0048] In addition, this embodiment also has advantages in heat dissipation. IGBT generates quite serious heat during operation. A large number of IGBTs are evenly distributed on each PCB board. On the one hand, the heat dissipation load of the radiator can be greatly reduced to ensure the heat dissipation of each IGBT; on the other hand, the structure of stacking multiple IGBT boards can be reasonably controlled, and a larger size cooling fan can be selected. A large size cooling fan can easily increase the air volume, which further ensures the heat dissipation capacity of the whole machine.

[0049] This embodiment is not only of great significance from the perspective of circuit design, but also of great help to the heat dissipation duct design and structural design of the entire machine.

[0050] The utility model has the following beneficial effects through the design of the above embodiments: by setting a first IGBT board and a second IGBT board, the second IGBT board is connected in parallel with the first IGBT board, the first IGBT board includes a first six-tube parallel current magnetic coupling device, the second IGBT board includes a second six-tube parallel current magnetic coupling device, and the first six-tube parallel current magnetic coupling device and the second six-tube parallel current magnetic coupling device are configured the same; the IGBT's own characteristics and magnetic clamping are utilized to realize the instantaneous current sharing of the IGBT in parallel, that is, the magnetic clamping is utilized to limit the current of each The current that a PCB needs to withstand; IGBT can withstand a certain pulse current within ns when it is turned on or off. When multiple tubes are connected in parallel, although there is always one tube that is turned on first or turned off last, as long as the pulse current on each PCB is limited, the current equalization at the moment of switching can be done well, and the capacity of a single machine and the power density of the whole machine can be increased. The structure of stacking multiple IGBT boards can also be reasonably controlled, and a larger cooling fan can be selected. A large cooling fan can easily increase the air volume, which further ensures the heat dissipation capacity of the whole machine.

[0051] The present invention is described according to specific embodiments, but those skilled in the art should understand that various changes and equivalent substitutions can be made without departing from the scope of the present invention. In addition, in order to adapt to specific occasions of the present invention technology, many modifications can be made to the present invention without departing from its protection scope. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all embodiments that fall within the scope of protection of the claims.

Claims

1. A parallel current balancing device based on IGBT's own parameter characteristics, characterized in that: include: A first IGBT board, a second IGBT board, the second IGBT board is connected in parallel with the first IGBT board, the first IGBT board includes a first six-tube parallel current magnetic coupling device, the second IGBT board includes a second six-tube parallel current magnetic coupling device, and the first six-tube parallel current magnetic coupling device and the second six-tube parallel current magnetic coupling device are configured the same.

2. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 1, characterized in that: The first six-tube parallel current magnetic coupling device comprises: The collector of IGBT Q41 is respectively connected to the anode of diode D41, the collector of IGBT Q42, the anode of diode D42, the collector of IGBT Q43, the anode of diode D43, and one end of capacitor C21; the emitter of IGBT Q41 is respectively connected to the cathode of diode D41, the anode of diode D16, the collector of IGBT Q31, and the anode of diode D31.

3. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 2, characterized in that: The first six-tube parallel current magnetic coupling device also includes: The emitter of IGBT Q31 is connected to the cathode of diode D31, the anode of diode D21, the collector of IGBT Q21, the anode of diode D22, the collector of IGBT Q22, and the anode of diode D23, respectively; the collector of IGBT Q23, the emitter of IGBT Q32, the cathode of diode D32, the emitter of IGBT Q33, and the cathode of diode D33 are connected.

4. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 3, characterized in that: The first six-tube parallel current magnetic coupling device also includes: The emitter of IGBT Q21 is connected to the anode of diode D11 and the collector of IGBT Q11, respectively. The cathode of diode D21 is connected to the cathode of diode D15. The emitter of IGBT Q42 is connected to the cathode of diode D42, the collector of IGBT Q32 and the anode of diode D32, respectively.

5. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 4, characterized in that: The first six-tube parallel current magnetic coupling device also includes: The emitter of IGBT Q43 is respectively connected to the cathode of diode D43, the collector of IGBT Q33, and the anode of diode D33; the other end of capacitor C21 is respectively connected to the cathode of diode D16, the anode of diode D15, and one end of capacitor C11; the other end of capacitor C11 is respectively connected to the emitter of IGBT Q11, the cathode of diode D11, the emitter of IGBT Q12, the cathode of diode D12, the emitter of IGBT Q13, and the cathode of diode D13.

6. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 1, characterized in that: The second six-tube parallel current magnetic coupling device comprises: The collector of IGBT Q46 is respectively connected to the anode of diode D46, the collector of IGBT Q45, the anode of diode D45, the collector of IGBT Q44, the anode of diode D44, and one end of capacitor C22; the emitter of IGBT Q46 is respectively connected to the cathode of diode D46, the anode of diode D26, the collector of IGBT Q36, and the anode of diode D36.

7. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 6, characterized in that: The second six-tube parallel current magnetic coupling device also includes: The emitter of IGBT Q36 is connected to the cathode of diode D36, the anode of diode D26, the collector of IGBT Q26, the anode of diode D25, the collector of IGBT Q25, and the anode of diode D24, respectively; the collector of IGBT Q24, the emitter of IGBT Q35, the cathode of diode D35, the emitter of IGBT Q34, and the cathode of diode D34 are connected.

8. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 7, characterized in that: The second six-tube parallel current magnetic coupling device also includes: The emitter of IGBT Q26 is connected to the anode of diode D16 and the collector of IGBT Q16, respectively. The cathode of diode D26 is connected to the cathode of diode D25. The emitter of IGBT Q45 is connected to the cathode of diode D45, the collector of IGBT Q35 and the anode of diode D35, respectively. The emitter of IGBT Q44 is respectively connected to the cathode of diode D44, the collector of IGBT Q34, and the anode of diode D34; the other end of capacitor C22 is respectively connected to the cathode of diode D26, the anode of diode D25, and one end of capacitor C21; the other end of capacitor C21 is respectively connected to the emitter of IGBT Q16, the cathode of diode D16, the emitter of IGBT Q15, the cathode of diode D15, the emitter of IGBT Q16, and the cathode of diode D14.

9. The parallel current balancing device based on IGBT's own parameter characteristics according to claim 1, characterized in that: A transformer T1 is connected between the second IGBT board and the first IGBT board.

10. The parallel current balancing device based on IGBT's own parameter characteristics according to any one of claims 1 to 9, characterized in that: The number of the first IGBT boards is 2 to the power of n, and the number of the second IGBT boards is 2 to the power of n, where n is a natural number greater than or equal to 2.

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