An IGBT parallel current sharing circuit based on magnetic coupling inductance

Abstract

The application provides an IGBT parallel current sharing circuit based on a magnetic coupling inductor, which comprises a first IGBT half-bridge unit, a second IGBT half-bridge unit and a magnetic coupling inductor, the first IGBT half-bridge unit and the second IGBT half-bridge unit are arranged in parallel, the magnetic coupling inductor comprises a first winding and a second winding; the first IGBT half-bridge unit is connected in series with the first winding, and the second IGBT half-bridge unit is connected in series with the second winding; the first winding and the second winding are wound on the same magnetic core and are connected in the same name end reverse series mode to realize dynamic current balance between the first IGBT half-bridge unit and the second IGBT half-bridge unit through mutual inductance. The IGBT parallel current sharing circuit ensures current sharing between the two windings of the inductor through the coupling effect of the inductor, and further ensures current sharing of the IGBT.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and more specifically, to an IGBT parallel current sharing circuit based on magnetically coupled inductors. Background Technology

[0002] With the rapid development of new energy power generation and smart grid technologies, high-power energy storage converters are becoming increasingly important in power systems. IGBTs (Insulated Gate Bipolar Transistors), as the core power switching devices in converters, rely heavily on parallel connection technology to achieve high-power output. Currently, the industry commonly uses multiple IGBT modules connected in parallel to meet the high power requirements of energy storage converters.

[0003] In existing technologies, high-power energy storage converters typically employ a "hard parallel" IGBT module parallel scheme, where multiple IGBT devices are directly connected in parallel to the same bridge arm, achieving synchronous operation of the multiple IGBTs through simple electrical connections. However, the current sharing performance of this scheme relies entirely on the consistency of the parameters of the parallel IGBT modules themselves, including the matching of parameters such as on-state voltage drop, switching characteristics, and thermal resistance. During the device manufacturing process, even IGBT modules from the same batch will have inherent differences in parameters. When these modules operate in the aforementioned manner, these parameter differences will lead to uneven current distribution, potentially causing some IGBTs to be damaged due to overload, severely impacting the reliability and lifespan of the converter. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a parallel current sharing circuit for IGBTs based on magnetically coupled inductors, which ensures current sharing between the two windings of the inductor through the coupling effect of the inductor, thereby ensuring current sharing of the IGBTs and solving the problem of current unevenness caused by device discreteness.

[0005] This application provides an IGBT parallel current sharing circuit based on a magnetically coupled inductor. The IGBT parallel current sharing circuit includes a first IGBT half-bridge unit, a second IGBT half-bridge unit, and a magnetically coupled inductor. The first IGBT half-bridge unit and the second IGBT half-bridge unit are connected in parallel. The magnetically coupled inductor includes a first winding and a second winding. The first IGBT half-bridge unit is connected in series with the first winding, and the second IGBT half-bridge unit is connected in series with the second winding; The first winding and the second winding are wound on the same magnetic core and connected in series with the same terminals in reverse order, so as to achieve dynamic current balance between the first IGBT half-bridge unit and the second IGBT half-bridge unit through mutual inductance.

[0006] Furthermore, both the first IGBT half-bridge unit and the second IGBT half-bridge unit include an IGBT module and an anti-parallel diode.

[0007] Furthermore, the first IGBT half-bridge unit and the second IGBT half-bridge unit constitute one arm of a full-bridge or three-phase bridge topology, and are independently connected to the main circuit through their respective coupling windings.

[0008] Furthermore, the first winding and the second winding have the same number of turns or are designed to be matched according to the parameters of the IGBT modules connected in series.

[0009] Furthermore, the IGBT parallel current sharing circuit also includes a drive control unit, with the first IGBT half-bridge unit and the second IGBT half-bridge unit respectively connected in series with the drive control unit.

[0010] Furthermore, the drive control unit generates a synchronous drive signal and simultaneously sends the synchronous drive signal to the first IGBT half-bridge unit and the second IGBT half-bridge unit.

[0011] Furthermore, the magnetically coupled inductor automatically generates a reverse electromotive force to adjust the voltage distribution when a transient current difference occurs, through the mutual inductance between the first winding and the second winding.

[0012] Furthermore, the magnetic core is made of ferrite, amorphous or nanocrystalline materials, and is shaped as EE, UI or toroidal.

[0013] This application provides an IGBT parallel current sharing circuit based on a magnetically coupled inductor. The IGBT parallel current sharing circuit includes a first IGBT half-bridge unit, a second IGBT half-bridge unit, and a magnetically coupled inductor. The first IGBT half-bridge unit and the second IGBT half-bridge unit are connected in parallel. The magnetically coupled inductor includes a first winding and a second winding. The first IGBT half-bridge unit is connected in series with the first winding, and the second IGBT half-bridge unit is connected in series with the second winding. The first winding and the second winding are wound on the same magnetic core and connected in series with the same terminals in reverse order, so as to achieve dynamic current balance between the first IGBT half-bridge unit and the second IGBT half-bridge unit through mutual inductance.

[0014] This application constructs a parallel current sharing solution for IGBTs by introducing a magnetically coupled inductor into the parallel branch of the IGBT. The coupling effect of the inductor ensures current sharing between the two windings of the inductor, thereby guaranteeing current sharing within the IGBT. Compared to traditional "hard parallel" solutions, this application not only solves the current unevenness problem caused by device discreteness but also offers advantages such as fast response, no need for additional control, and ease of integration.

[0015] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This application provides a schematic diagram of a prior art parallel connection scheme for IGBT modules. Figure 2 A schematic diagram of a parallel current sharing circuit of IGBTs based on magnetically coupled inductors provided in an embodiment of this application; Figure 3 This is a schematic diagram of a magnetically coupled inductor current sharing method provided in an embodiment of this application.

[0018] Referring to the accompanying drawings, the reference numerals in the embodiments of this application are as follows: 20 - IGBT parallel current sharing circuit; 21 - First IGBT half-bridge unit; 22 - Second IGBT half-bridge unit; 23 - Magnetic coupling inductor; N1 - First winding; N2 - Second winding. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0020] First, the applicable scenarios for this application are introduced. This application can be applied in the field of electronic circuit technology as a parallel current sharing circuit for IGBTs.

[0021] With the rapid development of new energy power generation and smart grid technologies, high-power energy storage converters are becoming increasingly important in power systems. IGBTs (Insulated Gate Bipolar Transistors), as the core power switching devices in converters, rely heavily on parallel connection technology to achieve high-power output. Currently, the industry commonly uses multiple IGBT modules connected in parallel to meet the high power requirements of energy storage converters.

[0022] Please see Figure 1 , Figure 1 This is a schematic diagram of a prior art parallel connection scheme for IGBT modules provided as an embodiment of this application. Figure 1 As shown, in existing technologies, high-power energy storage converters typically employ a "hard parallel" IGBT module parallel scheme, where multiple IGBT devices are directly connected in parallel to the same bridge arm, achieving synchronous operation of the multiple IGBTs through simple electrical connections. However, the current sharing performance of this scheme depends entirely on the consistency of the parameters of the parallel IGBT modules themselves, including the matching of parameters such as on-state voltage drop, switching characteristics, and thermal resistance. During the device manufacturing process, even IGBT modules from the same batch will have inherent differences in their parameters. When these modules operate in the aforementioned manner, these parameter differences will lead to uneven current distribution, and some IGBTs may be damaged due to overload, severely affecting the reliability and service life of the converter.

[0023] Based on this, this application provides an IGBT parallel current sharing circuit based on a magnetically coupled inductor. The coupling effect of the inductor ensures current sharing between the two windings of the inductor, thereby ensuring current sharing of the IGBT and solving the problem of current unevenness caused by device discreteness.

[0024] Please see Figure 2 , Figure 2 This is a schematic diagram of a parallel current-sharing circuit for IGBTs based on magnetically coupled inductors, provided as an embodiment of this application. Figure 2 As shown in the figure, the IGBT parallel current sharing circuit 20 provided in this application embodiment includes a first IGBT half-bridge unit 21, a second IGBT half-bridge unit 22 and a magnetically coupled inductor 23. The first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 are connected in parallel. The magnetically coupled inductor 23 includes a first winding N1 and a second winding N2.

[0025] The first IGBT half-bridge unit 21 is connected in series with the first winding N1, and the second IGBT half-bridge unit 22 is connected in series with the second winding N2.

[0026] The first winding N1 and the second winding N2 are wound on the same magnetic core and connected in series with the same terminals in opposite directions to achieve dynamic current balance between the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 through mutual inductance.

[0027] Here, when transient current imbalance occurs during the turn-on or turn-off process of two IGBT units, due to the mutual inductance, the branch with the larger current will induce a reverse electromotive force in the other branch, suppressing its further increase and achieving the purpose of dynamic automatic adjustment of current distribution. For example, if the current in the first IGBT branch rises rapidly at a certain moment, a voltage that hinders its rapid current rise will be generated in the second winding N2 through mutual inductance, and vice versa, thereby achieving bidirectional dynamic current sharing. The design of the magnetic coupling inductor 23 in this application forms a negative feedback mechanism between the two parallel branches, effectively alleviating the problem of static and dynamic current imbalance caused by differences in device parameters. By introducing the magnetic coupling inductor 23 with a reverse connection structure of the same terminal, dynamic current balance control between parallel IGBT modules is achieved, which does not depend on the high consistency of IGBT module parameters, significantly improving the reliability and fault tolerance of the multi-module parallel system, reducing the risk of individual IGBT overload, and extending the overall system life.

[0028] For further details, please refer to Figure 2 Both the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 include IGBT modules and anti-parallel diodes. Specifically, the anti-parallel diode is integrated inside the IGBT module or mounted separately externally to provide a path for reverse current under inductive loads, preventing the IGBT from being damaged by reverse voltage. In practical applications, such as in energy storage converters or inverter bridge arms, the IGBT is responsible for the main current conduction and cutoff, while the anti-parallel diode undertakes the freewheeling function during IGBT turn-off. Since the magnetic coupling inductor 23 acts simultaneously during the IGBT conduction phase and the diode freewheeling phase, good current balance can be achieved during both forward conduction and reverse freewheeling. In this way, the IGBT half-bridge unit takes into account the current sharing performance of the IGBT switching process and the diode freewheeling phase, improving the current balance throughout the entire operating cycle.

[0029] As an optional embodiment, the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 constitute one arm of a full-bridge or three-phase bridge topology and are independently connected to the main circuit through their respective coupling windings. Here, taking a three-phase inverter as an example, in each phase, at least one of the upper and lower arms consists of two parallel half-bridge units with magnetically coupled inductors 23. Each arm is controlled to switch on and off by a drive signal, and the magnetically coupled inductors 23 are only placed in the parallel branches and do not affect the main topology.

[0030] Furthermore, the number of turns of the first winding N1 and the second winding N2 are the same or are matched according to the parameters of the IGBT modules connected in series.

[0031] As an optional embodiment, the IGBT parallel current sharing circuit 20 further includes a drive control unit, wherein the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 are connected in series with the drive control unit.

[0032] Specifically, the IGBT parallel current sharing circuit 20 also includes a drive control unit, which is connected to the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 respectively, and is used to send control signals to both. The drive control unit receives PWM commands from the controller (such as DSP or FPGA), and synchronously drives each IGBT module after isolation and amplification. The drive control unit uniformly schedules multiple IGBT modules to ensure that the switching timing of the parallel IGBTs is consistent, reducing transient current surges caused by differences in drive timing.

[0033] Furthermore, the drive control unit generates a synchronous drive signal and simultaneously sends the synchronous drive signal to the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22.

[0034] Here, to ensure signal synchronization, the drive control unit adopts a common-source drive architecture or a multi-channel synchronous drive chip, and optimizes the PCB layout to ensure consistent trace lengths, minimizing transmission delay differences. This eliminates transient current imbalances caused by asynchronous drive signals, and, in conjunction with the dynamic adjustment mechanism of the magnetically coupled inductor 23, achieves dual current sharing protection, significantly reducing circulating currents and electromagnetic interference at startup.

[0035] Furthermore, the magnetically coupled inductor 23 automatically generates a reverse electromotive force to adjust the voltage distribution when a transient current difference occurs, through the mutual inductance between the first winding N1 and the second winding N2.

[0036] Here, when a sudden change occurs in the current of a branch (such as during the initial switching process or a load jump), because the first winding N1 and the second winding N2 are wound on the same magnetic core and connected in opposite directions, the branch with the higher rate of current change will induce a reverse electromotive force (EMF) in the other branch through the mutual inductance M. This EMF is equivalent to introducing a dynamic impedance in that branch, suppressing the rapid increase in current. For example, if the current in the first IGBT branch increases faster, a positive voltage (opposite to its conduction direction) is induced in the second winding N2, reducing its voltage margin and prompting more current to flow to the first branch until dynamic equilibrium is reached. This negative feedback mechanism continues to operate throughout the entire switching cycle.

[0037] In this way, passive active current sharing is achieved by utilizing the principle of electromagnetic induction at the physical level. No additional sensors or complex algorithms are required, the response speed is fast, and current spikes can be effectively suppressed during switching transients.

[0038] Please see Figure 3 , Figure 3 This is a schematic diagram of a magnetically coupled inductor current sharing method provided in an embodiment of this application. Figure 3 As shown, the mutual inductance coefficient of the two windings N1 and N2 is M. When the current i1 flows through the N1 winding, the current i2 flows through the N2 winding. Then the voltage equation on the N1 / N2 winding is as follows, where the voltage on the winding consists of two parts, one part is the self-induced electromotive force, and the other part is the mutual induced electromotive force.

[0039]

[0040]

[0041] The self-induced electromotive force on winding N1 is Mutual inductance electromotive force is "-" refers to the wrapping method of the heteronym.

[0042] It can be seen that when i1 increases and i2 decreases, the voltage U1 on the N1 winding increases and the voltage on the U2 winding decreases. This indicates that Uload = Uinv - U1 voltage decreases, which leads to i1 decreasing, and the dynamic current sharing process is established.

[0043] As an optional embodiment, the magnetic core is made of ferrite, amorphous or nanocrystalline material, and is in the shape of EE type, UI type or toroidal.

[0044] Here, the magnetic core of the magnetically coupled inductor 23 is preferably made of a high-permeability, low-loss material, such as ferrite, amorphous alloy, or nanocrystalline material. Ferrite is suitable for mid-to-high frequency (20kHz~100kHz) applications, is low-cost, and easy to process; amorphous materials have lower iron loss and are suitable for higher frequencies (>100kHz) and high-temperature environments; nanocrystalline materials combine high saturation flux density and excellent high-frequency characteristics, making them suitable for high-current, high-efficiency applications. The core shape can be EE type, UI type, or toroidal structure. Toroidal cores have the lowest leakage inductance and the tightest coupling, but winding is more difficult; EE / UI type cores facilitate automated winding and are suitable for mass production.

[0045] According to the IGBT parallel current sharing circuit 20 based on magnetic coupling inductor 23 provided in this application, the IGBT parallel current sharing circuit 20 includes a first IGBT half-bridge unit 21, a second IGBT half-bridge unit 22, and a magnetic coupling inductor 23. The first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 are connected in parallel. The magnetic coupling inductor 23 includes a first winding N1 and a second winding N2. The first IGBT half-bridge unit 21 is connected in series with the first winding N1, and the second IGBT half-bridge unit 22 is connected in series with the second winding N2. The first winding N1 and the second winding N2 are wound on the same magnetic core and connected in series with the same terminals in reverse order, so as to achieve dynamic current balance between the first IGBT half-bridge unit 21 and the second IGBT half-bridge unit 22 through mutual inductance.

[0046] This application constructs a parallel current sharing solution for IGBTs by introducing a magnetically coupled inductor into the parallel branch of the IGBT. The coupling effect of the inductor ensures current sharing between the two windings of the inductor, thereby guaranteeing current sharing within the IGBT. Compared to traditional "hard parallel" solutions, this application not only solves the current unevenness problem caused by device discreteness but also offers advantages such as fast response, no need for additional control, and ease of integration.

[0047] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0048] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0049] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0050] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion 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 application. 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.

[0051] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A parallel current-sharing circuit for IGBTs based on magnetically coupled inductors, characterized in that, The IGBT parallel current sharing circuit includes a first IGBT half-bridge unit, a second IGBT half-bridge unit, and a magnetically coupled inductor. The first IGBT half-bridge unit and the second IGBT half-bridge unit are connected in parallel. The magnetically coupled inductor includes a first winding and a second winding. The first IGBT half-bridge unit is connected in series with the first winding, and the second IGBT half-bridge unit is connected in series with the second winding; The first winding and the second winding are wound on the same magnetic core and connected in series with the same terminals in reverse order, so as to achieve dynamic current balance between the first IGBT half-bridge unit and the second IGBT half-bridge unit through mutual inductance.

2. The IGBT parallel current sharing circuit according to claim 1, characterized in that, Both the first IGBT half-bridge unit and the second IGBT half-bridge unit include an IGBT module and an anti-parallel diode.

3. The IGBT parallel current sharing circuit according to claim 1, characterized in that, The first IGBT half-bridge unit and the second IGBT half-bridge unit constitute one arm of a full-bridge or three-phase bridge topology, and are independently connected to the main circuit through their respective coupling windings.

4. The IGBT parallel current sharing circuit according to claim 1, characterized in that, The first winding and the second winding have the same number of turns or are designed to be matched according to the parameters of the IGBT modules connected in series.

5. The IGBT parallel current sharing circuit according to claim 1, characterized in that, The IGBT parallel current sharing circuit also includes a drive control unit, and the first IGBT half-bridge unit and the second IGBT half-bridge unit are respectively connected in series with the drive control unit.

6. The IGBT parallel current sharing circuit according to claim 5, characterized in that, The drive control unit generates a synchronous drive signal and sends the synchronous drive signal to both the first IGBT half-bridge unit and the second IGBT half-bridge unit simultaneously.

7. The IGBT parallel current sharing circuit according to claim 1, characterized in that, The magnetically coupled inductor automatically generates a reverse electromotive force to adjust the voltage distribution when a transient current difference occurs, through the mutual inductance between the first winding and the second winding.

8. The IGBT parallel current sharing circuit according to claim 1, characterized in that, The magnetic core is made of ferrite, amorphous or nanocrystalline materials, and is in the shape of EE, UI or ring.

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