IGBT active clamping protection circuit and inverter

Abstract

The utility model relates to the technical field of power electronics, and discloses an IGBT active clamping protection circuit and an inverter. The circuit comprises an IGBT (Insulated Gate Bipolar Translator) tube and an active clamping module, the collector electrode of the IGBT tube is connected with the positive electrode of the direct current bus and is used for controlling the on-off of the inverter circuit. The active clamping module comprises a positive temperature coefficient resistance circuit and a transient voltage suppression circuit; and the positive temperature coefficient resistance circuit is connected in series with the transient voltage suppression circuit, is arranged between the collector electrode and the gate electrode of the IGBT tube, and is used for clamping the potential of the collector electrode to a target value during overcurrent turn-off and short-circuit protection. An active clamping module with a positive temperature coefficient resistance circuit is arranged to protect an IGBT tube during overcurrent and short circuit, and the resistance value of the positive temperature coefficient resistance circuit is increased along with temperature rise, so that the active clamping module clamps the potential of a collector electrode of the IGBT tube to a target value; the IGBT can be protected at any temperature, and meanwhile, normal work of the IGBT cannot be influenced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to an IGBT active clamping protection circuit and an inverter. Background Art

[0002] Inverters are core components for power conversion in renewable energy. High-power inverters inevitably use IGBT (Insulated Gate Bipolar Transistor) modules as the switching devices in the main topology. In actual use, inverters may experience abnormal conditions such as arm short circuits and load short circuits, which can cause overcurrent in the IGBT modules and lead to damage.

[0003] At present, in order to protect the IGBT module from damage, an active clamping circuit is set for protection. Although the active clamping protection circuit of the existing technology can protect the IGBT to a certain extent when controlling the shutdown of the IGBT module, the clamping voltage fluctuates greatly under different temperature coefficients. Under high or low temperature conditions, it still cannot protect the IGBT. Utility Model Content

[0004] In view of this, the present application proposes an IGBT active clamping protection circuit and an inverter to solve the problem that the existing IGBT protection circuit is still unable to protect the IGBT.

[0005] A first aspect of the present application provides an IGBT active clamping protection circuit, comprising: an IGBT tube and an active clamping module; the collector of the IGBT tube is connected to the positive pole of a DC bus, and is used to control the on and off of an inverter circuit; the active clamping module comprises a positive temperature coefficient resistor circuit and a transient voltage suppression circuit; the positive temperature coefficient resistor circuit and the transient voltage suppression circuit are connected in series and are arranged between the collector and gate of the IGBT tube, and are used to clamp the collector potential to a target value during overcurrent shutdown and short-circuit protection.

[0006] In a feasible embodiment, the positive temperature coefficient resistor circuit includes a matching resistor circuit and a positive temperature coefficient resistor; the matching resistor circuit is connected in parallel with the positive temperature coefficient resistor, one end of the positive temperature coefficient resistor is connected to the transient voltage suppression circuit, and the other end of the positive temperature coefficient resistor is connected to the gate.

[0007] In a possible implementation, the transient voltage suppression circuit includes at least one transient voltage suppression diode.

[0008] In a feasible implementation manner, the transient voltage suppression diode is a unidirectional transient voltage suppression diode or a bidirectional transient voltage suppression diode.

[0009] In a feasible embodiment, if the at least one transient voltage suppression diode is at least two unidirectional transient voltage suppression diodes, each of the unidirectional transient voltage suppression diodes is connected in series, and the anode of the series-connected circuit is connected to the positive temperature coefficient resistor, and the cathode of the series-connected circuit is connected to the collector.

[0010] In a feasible implementation manner, the transient voltage suppression circuit further includes a fast recovery diode circuit, the anode of the fast recovery diode circuit is connected to the transient voltage suppression diode, and the cathode of the fast recovery diode circuit is connected to the positive temperature coefficient resistor.

[0011] In a feasible implementation manner, the IGBT active clamping protection circuit further includes: a gate drive circuit connected in series to the gate of the IGBT, for reducing a voltage spike between the collector and emitter of the IGBT tube.

[0012] In a feasible embodiment, the gate drive circuit includes: a drive resistance circuit and a capacitor circuit, the drive resistance circuit is arranged between the gate of the IGBT tube and the output end of the drive chip, and the capacitor circuit is arranged between the gate and emitter of the IGBT tube.

[0013] In a feasible implementation manner, the IGBT active clamping protection circuit further includes: an absorption buffer circuit provided between the collector and emitter of the IGBT tube.

[0014] A second aspect of the present application provides an inverter, comprising at least one IGBT active clamping protection circuit and a driver chip provided above; the driver chip is arranged on one side of the gate of the IGBT tube in the IGBT active clamping protection circuit.

[0015] The technical solution provided in this application includes an IGBT and an active clamping module. The collector of the IGBT is connected to the positive pole of the DC bus and is used to control the on / off of the inverter circuit. The active clamping module includes a positive temperature coefficient resistor circuit and a transient voltage suppression circuit. The positive temperature coefficient resistor circuit and the transient voltage suppression circuit are connected in series and arranged between the collector and gate of the IGBT to clamp the collector potential to a target value during overcurrent shutdown and short-circuit protection. This application provides protection for the IGBT during overcurrent and short-circuit conditions by providing an active clamping module with a positive temperature coefficient resistor circuit. Because the resistance of the positive temperature coefficient resistor circuit increases with increasing temperature, the active clamping module clamps the collector potential of the IGBT to the target value, ensuring protection for the IGBT at any temperature without affecting its normal operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A first schematic diagram of an IGBT active clamping protection circuit provided in an embodiment of the present application;

[0017] Figure 2 A second schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0018] Figure 3 A third schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0019] Figure 4 A fourth schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0020] Figure 5 A fifth schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0021] Figure 6 A circuit schematic diagram of an IGBT active clamping protection circuit provided in an embodiment of the present application;

[0022] Figure 7 Another circuit schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0023] Figure 8 A sixth schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0024] Figure 9 Another circuit schematic diagram of the IGBT active clamping protection circuit provided in an embodiment of the present application;

[0025] Figure 10 A schematic diagram of an inverter provided in an embodiment of the present application;

[0026] Figure 11 Another schematic diagram of the inverter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The present application provides an IGBT active clamping protection circuit and inverter, which mainly suppresses the collector voltage of the IGBT tube by adding a series positive temperature coefficient (PTC) resistor circuit in the active clamping circuit, thereby ensuring that the limiting resistor can control the collector current even under high temperature conditions, thereby controlling the increase in the collector voltage to ensure the protection capability of the IGBT.

[0028] The terms "first," "second," "third," "fourth," etc. (if any) in the specification and claims of the present application and in the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential sequence. It should be understood that the numbers used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or apparatus.

[0029] like Figure 1 As shown, an embodiment of the present application provides an IGBT active clamping protection circuit, comprising an IGBT 110 and an active clamping module 120. The collector and emitter of the IGBT 110 are connected to the positive and negative poles of a DC bus, respectively. One end of the active clamping module 120 is connected to the collector of the IGBT 110, and the other end is connected to the gate of the IGBT 110. The active clamping module 120 protects the IGBT 110 by, when the peak voltage Vce between the collector and emitter of the IGBT 110 exceeds a certain value, controlling the IGBT 110 to turn off more slowly through the current generated by the active clamping module 120, thereby reducing the turn-off di / dt (di / dt), which refers to the change in current per unit time, i.e., the derivative of current with respect to time, thereby clamping the Vce voltage. It can be understood that the clamping process of this module is essentially a negative feedback loop, with the potential of the collector of the IGBT 110 being the controlled object.

[0030] In this embodiment, the collector of the IGBT tube 110 is connected to the positive electrode of the DC bus to control the on / off of the inverter circuit; the active clamping module 120 includes a positive temperature coefficient resistor circuit 121 and a transient voltage suppression circuit 122; the positive temperature coefficient resistor circuit 121 and the transient voltage suppression circuit 122 are connected in series and are arranged between the collector and gate of the IGBT tube 110 to clamp the potential of the collector to a target value during overcurrent shutdown and short-circuit protection. Figure 2 shown.

[0031] It should be noted that the collector of the IGBT tube 110 is connected to the positive DC bus, and the emitter is connected to the negative DC bus. When the positive temperature coefficient resistor circuit 121 is connected in series with the transient voltage suppression circuit 122, the anode of the transient voltage suppression circuit 122 is actually connected to the positive temperature coefficient resistor circuit 121, and the cathode of the transient voltage suppression circuit 122 is connected to the collector of the IGBT tube 110. When the voltage between the collector and the emitter reaches the breakdown voltage of the transient voltage suppression circuit 122, the active clamping and the positive temperature coefficient resistor circuit 121 generate a corresponding current to clamp the voltage between the collector and the emitter near the target value, so as to buffer the shutdown of the IGBT tube 110.

[0032] The positive temperature coefficient resistor circuit 121 is actually an impedance circuit including a PTC resistor. Under the action of the PTC resistor, the circuit can ensure that the resistance of the PTC resistor increases as the operating temperature of the IGBT tube 110 increases, thereby ensuring the matching of the current and the Vce peak voltage, and avoiding the problem that the Vce voltage increases due to the temperature increase, which makes it impossible to protect the IGBT tube.

[0033] In another embodiment, the positive temperature coefficient resistor circuit 121 includes a matching resistor circuit 1211 and a positive temperature coefficient resistor 1212; the matching resistor circuit 1211 is connected in parallel with the positive temperature coefficient resistor 1212, one end of the positive temperature coefficient resistor 1212 is connected to the transient voltage suppression circuit 122, and the other end of the positive temperature coefficient resistor 1212 is connected to the gate.

[0034] It is understandable that the positive temperature coefficient resistor 1212 can be set to one or more. When it is set to one, the two ends of the positive temperature coefficient resistor 1212 are respectively connected to the two ends of the matching resistor circuit 1211 to achieve parallel connection, and then connected in series with the transient voltage suppression circuit 122. When it is set to multiple, the multiple positive temperature coefficient resistors 1212 can be connected in series and then connected in parallel with the matching resistor circuit 1211, such as Figure 3 As shown, two positive temperature coefficient resistors 1212 are connected in series as an example, and multiple positive temperature coefficient resistors 1212 can also be connected in parallel with the matching resistor circuit 1211, such as Figure 4 As shown, two positive temperature coefficient resistors 1212 are connected in parallel as an example. It is also possible that multiple positive temperature coefficient resistors 1212 are connected in series and in parallel with the matching resistor circuit 1211. Figure 5As shown, three positive temperature coefficient resistors 1212 are connected in series and parallel as an example. The specific number of positive temperature coefficient resistors 1212 can be set according to actual design requirements. For example, the initial resistance value of the positive temperature coefficient resistor 1212 and the resistance change amplitude and trend with temperature can be determined based on the current generated by the breakdown voltage of the transient voltage suppression circuit 122, thereby determining the specific number of positive temperature coefficient resistors 1212 and the series and parallel connection method.

[0035] Furthermore, the matching resistor circuit 1211 can be a single resistor or multiple resistors. Regardless of whether it is composed of a single resistor or multiple resistors, the resistors used are ordinary resistors, and there is no need to consider the impact of temperature on the resistance value. When multiple resistors are used in the design, the multiple resistors can be connected in parallel and / or in series. Of course, the resistance value of the matching resistor circuit 1211 needs to be determined based on the current generated by the breakdown voltage of the transient voltage suppression circuit 122.

[0036] In another embodiment, the transient voltage suppression circuit 122 is a circuit composed of a transient voltage suppression diode 1221, which may specifically include at least one transient voltage suppression diode. When two or more transient voltage suppression diodes are included, the transient voltage suppression diodes are connected in series and then connected in series with the positive temperature coefficient resistor circuit 121.

[0037] By implementing the above-mentioned IGBT active clamping protection circuit, an active clamping module with a positive temperature coefficient resistor circuit is provided to protect the IGBT tube from overcurrent and short circuit. Since the resistance of the positive temperature coefficient resistor circuit increases with increasing temperature, the active clamping module clamps the potential of the collector of the IGBT tube to a target value, thereby ensuring that the IGBT can be protected at any temperature without affecting the normal operation of the IGBT. This solves the problem of the active clamping circuit in the prior art being unable to clamp the voltage at high temperatures, resulting in an inability to protect the IGBT.

[0038] In a feasible implementation manner, the transient voltage suppression (TVS) diode is a unidirectional transient voltage suppression diode or a bidirectional transient voltage suppression diode.

[0039] If unidirectional transient voltage suppression diodes are used to design the transient voltage suppression circuit 122, the unidirectional transient voltage suppression diodes are connected in series, and the anode of the series circuit is connected to the positive temperature coefficient resistor 1212, and the cathode of the series circuit is connected to the collector.

[0040] like Figure 6As shown, the transient voltage suppression circuit 122 is composed of a TVS diode D1 and a TVS diode D2, and the positive temperature coefficient resistor circuit 121 is composed of a resistor R1 and a PTC resistor R2, wherein the anode of D1 is connected to the cathode of D2, the cathode of D1 is connected to the collector C of the IGBT tube Q1, the anode of D2 is connected to one end of the PTC resistor R2, the other end of the PTC resistor R2 is connected to the gate G of the IGBT tube Q1, and the resistor R1 and the PTC resistor R2 are connected in parallel.

[0041] In another embodiment, when bidirectional transient voltage suppression diodes are used to design the transient voltage suppression circuit 122, each bidirectional transient voltage suppression diode is directly connected in series without distinguishing between the anode and the cathode. Figure 7 As shown, the transient voltage suppression circuit 122 is composed of a TVS diode D3 and a TVS diode D4, and the positive temperature coefficient resistor circuit 121 is connected to the Figure 3 Same as in the example, D3 and D4 are connected in series and then connected in series with the PTC resistor R2.

[0042] In one possible implementation, Figure 8 As shown, the transient voltage suppression circuit 122 further includes a fast recovery diode circuit 1222. The anode of the fast recovery diode circuit 1222 is connected to the transient voltage suppression diode 1221, and the cathode of the fast recovery diode circuit 1222 is connected to the positive temperature coefficient resistor 1212. It should be noted that the fast recovery diode circuit 1222 can be composed of one or more diodes connected in series.

[0043] It is understandable that by setting two TVS diodes in the active clamping module 120 to match the clamping voltage by series voltage division, and setting a fast recovery diode circuit 1222 to quickly discharge the energy of the TVS diode, overcurrent or short circuit protection of the IGBT tube is achieved.

[0044] In another embodiment, the IGBT active clamping protection circuit further includes: a gate drive circuit 130 connected in series to the gate of the IGBT tube 110 , for reducing a voltage spike between the collector and emitter of the IGBT tube 110 .

[0045] It is understood that the gate drive circuit 130 includes a drive resistor circuit 131 and a capacitor circuit 132. The drive resistor circuit 131 is located between the gate of the IGBT 110 and the output terminal of the driver chip, while the capacitor circuit 132 is located between the gate and emitter of the IGBT 110. The drive resistor circuit 131 is designed to increase the off-resistance of the IGBT 110 and reduce the turn-off di / dt, thereby reducing the Vce spike. The capacitor circuit 132 is externally connected to Cge to further reduce the turn-off di / dt, thereby reducing the Vce spike and achieving the purpose of protecting the IGBT. It should be noted that the drive circuit 131 includes an on-resistance and an off-resistance connected in parallel, and the capacitor circuit 132 is composed of at least a capacitor and a resistor.

[0046] Furthermore, the IGBT active clamping protection circuit also includes an absorption snubber circuit 140 disposed between the collector and emitter of the IGBT 110. This absorption snubber circuit 140 is designed by selecting an appropriate resistor R, capacitor C, and diode D. The resistor R, capacitor C, and diode D are first combined in series and parallel, and then connected in parallel between the collector and emitter of the IGBT 110. This absorption snubber circuit 140 can absorb the surge voltage generated when the collector-emitter voltage Vce is turned off, further protecting the IGBT from overcurrent or short-circuit.

[0047] like Figure 9 As shown, the driving resistance circuit 131 is composed of a TVS unidirectional diode D5, resistors R3, R4 and R5, the capacitor circuit 132 is composed of resistors R6, R7 and capacitor C1, the positive temperature coefficient resistor circuit 121 is composed of a PTC resistor R2 and a resistor R1 in parallel, and the transient voltage suppression circuit 122 is composed of two TVS bidirectional diodes D3 and D4 and a fast recovery diode D6 in series, wherein the TVS unidirectional diode D4 is connected in series with the resistor R3 and then in parallel with the resistors R4 and R5, and then connected to the gate G of the IGBT tube 110; the resistor R6 is connected in series with the capacitor C1 and then in parallel with the resistor R7, and then the entire capacitor circuit 132 is connected in series between the gate G and the emitter E of the IGBT tube 110, and the emitter E is connected to the negative DC bus.

[0048] The absorption buffer circuit 140 is composed of a resistor R8, a diode D7 and a capacitor C2. After the resistor R8 and the diode D7 are connected in parallel, the anode of the diode D7 is connected to the collector, the cathode is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the emitter.

[0049] Through the implementation of this embodiment, a PTC resistor circuit is connected in series on the basis of a traditional active clamping circuit to balance the temperature-affected breakdown current or leakage current of the TVS diode at high and low temperatures, thereby affecting the fluctuation of Vce clamping, thereby clamping the collector potential of the IGBT to near the target value without excessive fluctuation and without affecting the normal operation of the IGBT.

[0050] The present application also provides an inverter, which includes at least one IGBT active clamping protection circuit 710 and a driver chip 720 provided in the above embodiment; the driver chip 720 is arranged on one side of the gate of the IGBT tube 110 in the IGBT active clamping protection circuit 710, as shown in FIG. Figure 7 As shown, the circuit structure of the IGBT active clamping protection circuit 710 is similar to Figure 1-6 The same is not repeated here.

[0051] It should be noted that the IGBT active clamping protection circuit 710 corresponds to one switching device, that is, one IGBT tube, and multiple IGBT tubes can be set in the inverter. Figure 10 Take one as an example.

[0052] Of course, more than two IGBTs can be provided. For two IGBTs, the two IGBTs Q2 and Q3 are connected in series to form a half-bridge circuit, and an IGBT active clamping protection circuit 710 is provided for each IGBT. Figure 11 As shown, two TVS diodes D52 and D53 or two TVS diodes D55 and D56 are matched by series voltage division to clamp the voltage Vce of Q22 and Q23 to near the corresponding target voltage. D54 and D57 are fast recovery diodes that quickly discharge the energy of the TVS diodes. R161 and R163 are ordinary resistors, and large-package chip resistors can be used. The purpose is to balance the temperature changes of R162 and R164.

[0053] R161, R162, R163 and R164 must meet certain ratios:

[0054] Req=R161*R162 / (R161+R162),

[0055] Req=R163*R164 / (R163+R164).

[0056] When the temperature rises, Req increases, Ipapp decreases, and thus VCLmax decreases accordingly.

[0057] In this application, a method of controlling the collector voltage of the IGBT tube by adding a series positive temperature coefficient (PTC) resistor circuit in the active clamping circuit is adopted, so that the control of the collector current by the limiting resistor can be ensured even under high temperature conditions, thereby controlling the increase of the collector voltage to ensure the protection capability of the IGBT.

[0058] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art who is familiar with the technical field can still modify the technical solutions described in the above embodiments within the technical scope disclosed in the present application, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate from the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An IGBT active clamping protection circuit, characterized in that: include: IGBT tube and active clamp module; The collector of the IGBT tube is connected to the positive electrode of the DC bus to control the on and off of the inverter circuit; The active clamping module includes a positive temperature coefficient resistor circuit and a transient voltage suppression circuit; the positive temperature coefficient resistor circuit and the transient voltage suppression circuit are connected in series and arranged between the collector and gate of the IGBT tube, and are used to clamp the potential of the collector to the target value during overcurrent shutdown and short-circuit protection.

2. The IGBT active clamping protection circuit according to claim 1, characterized in that: The positive temperature coefficient resistance circuit includes a matching resistance circuit and a positive temperature coefficient resistor; The matching resistor circuit is connected in parallel with the positive temperature coefficient resistor, one end of the positive temperature coefficient resistor is connected to the transient voltage suppression circuit, and the other end of the positive temperature coefficient resistor is connected to the gate.

3. The IGBT active clamping protection circuit according to claim 2, characterized in that: The transient voltage suppression circuit includes at least one transient voltage suppression diode.

4. The IGBT active clamping protection circuit according to claim 3, characterized in that: The transient voltage suppression diode is a unidirectional transient voltage suppression diode or a bidirectional transient voltage suppression diode.

5. The IGBT active clamping protection circuit according to claim 4, characterized in that: If the at least one transient voltage suppression diode is at least two unidirectional transient voltage suppression diodes, the unidirectional transient voltage suppression diodes are connected in series, and the anode of the series-connected circuit is connected to the positive temperature coefficient resistor, and the cathode of the series-connected circuit is connected to the collector.

6. The IGBT active clamping protection circuit according to claim 3, characterized in that: The transient voltage suppression circuit further includes a fast recovery diode circuit, an anode of the fast recovery diode circuit is connected to the transient voltage suppression diode, and a cathode of the fast recovery diode circuit is connected to the positive temperature coefficient resistor.

7. The IGBT active clamping protection circuit according to any one of claims 1 to 6, characterized in that: The IGBT active clamping protection circuit further includes: a gate drive circuit connected in series to the gate of the IGBT tube, for reducing the voltage spike between the collector and emitter of the IGBT tube.

8. The IGBT active clamping protection circuit according to claim 7, characterized in that: The gate drive circuit includes: a drive resistor circuit and a capacitor circuit. The drive resistor circuit is arranged between the gate of the IGBT tube and the output end of the drive chip, and the capacitor circuit is arranged between the gate and emitter of the IGBT tube.

9. The IGBT active clamping protection circuit according to any one of claims 1 to 6, characterized in that: The IGBT active clamping protection circuit further includes an absorption buffer circuit provided between the collector and emitter of the IGBT tube.

10. An inverter, characterized in that: The inverter comprises at least one IGBT active clamping protection circuit and a driver chip according to any one of claims 1 to 9; the driver chip is arranged on one side of the gate of the IGBT tube in the IGBT active clamping protection circuit.

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