Circuit for eliminating IGBT short-circuit oscillation
By introducing series resistors and capacitors into the IGBT driving circuit, the problem of short-circuit oscillation of IGBT is solved, the circuit is simplified and the stability is improved, and the cost is reduced.
Patent Information
- Application Number
- CN202420987259.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-09
- Publication Date
- 2025-01-14
- Estimated Expiration
- 2034-05-09
AI Technical Summary
IGBTs are prone to oscillation when short-circuit failures, resulting in complexity of the drive circuit, increasing cost and reducing stability. It is difficult for the prior art to effectively suppress short-circuit oscillation, affecting the normal operation of the motor driver.
Design a circuit including resistors R1, R2, R3, R4, insulated gate bipolar transistors Q3, Q5, and capacitors C3, C4. The series resistor and capacitor are connected to suppress the short-circuit oscillation of the IGBT to ensure that the IGBT is stable in the short-circuit situation. Turn off.
It realizes stable opening and oscillation suppression when the IGBT is short-circuited, reduces circuit complexity and cost, and improves the stability of the IGBT and the performance of the driving circuit.
Smart Images
Figure CN222356344U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of circuits, in particular to a circuit for eliminating IGBT short-circuit oscillation. Background Art
[0002] When the motor driver is working, its operating conditions are very complicated. Short circuit and other faults often occur. Therefore, the short circuit protection function is very important, especially in the design of the drive circuit. In order to eliminate short circuit oscillation, the conventional approach is to suppress the oscillation of the short circuit current through a complex circuit. Because the IGBT must work in the safe operating area, that is, SOA. In order to ensure that the working SOA is within the VCE waveform, it cannot oscillate.
[0003] In the inverter circuit using IGBT as the switching device, due to the requirements of the working environment, it is necessary to design a driving circuit with multiple protection functions to drive the IGBT, and at the same time ensure that even if a short-circuit fault occurs in the IGBT, its driving circuit can be turned off in a timely and stable manner. Because of the parasitic tail current effect of the IGBT itself, it is necessary to increase the negative voltage to stably turn off the IGBT. However, this will greatly increase the cost of the driving circuit and increase the area. In addition, due to the parasitic capacitance and parasitic inductance parameters brought by the IGBT package itself, the actual product batch will deviate from the designer's intention, thereby affecting the stability of the IGBT. In particular, once a short-circuit oscillation occurs, some driving circuits that are not well designed will cause the VCE of the IGBT to oscillate. Utility Model Content
[0004] The utility model aims to detect when the power input voltage is too low, output a level jump signal when the power input voltage is too low, and thus control the switch of the switching power supply, and proposes a circuit for eliminating IGBT short-circuit oscillation.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] 1. A circuit for eliminating IGBT short-circuit oscillation, comprising:
[0007] Resistor R1, resistor R3, resistor R2, resistor R4, first transistor Q3, second transistor Q5, first capacitor C3, second capacitor C4;
[0008] The gate of the first transistor Q3 is connected in series with the resistor R1, the resistor R2 and the first capacitor C3 are connected in series between the gate and the emitter of the first transistor Q3, the emitter of the first transistor Q3 is connected to the gate of the second transistor Q5, the gate of the second transistor Q5 is connected in series with the resistor R3, and the resistor R4 and the first capacitor C4 are connected in series between the gate and the emitter of the second transistor Q5.
[0009] Preferably, the first transistor Q3 comprises an insulated gate bipolar transistor.
[0010] Preferably, the second transistor Q5 comprises an insulated gate bipolar transistor.
[0011] Preferably, the circuit comprises a power supply DC, and the collector of the first transistor Q3 and the emitter of the second transistor Q5 are respectively connected to a first output terminal and a second output terminal of the power supply DC.
[0012] Preferably, the emitter of the second transistor Q5 is grounded.
[0013] Compared with the prior art, the circuit for eliminating IGBT short-circuit oscillation in the embodiment of the utility model includes: a resistor R1, a resistor R3, a resistor R2, a resistor R4, a first transistor Q3, a second transistor Q5, a first capacitor C3, and a second capacitor C4; the gate of the first transistor Q3 is connected in series with the resistor R1, the resistor R2 and the first capacitor C3 are connected in series between the gate and the emitter of the first transistor Q3, the emitter of the first transistor Q3 is connected to the gate of the second transistor Q5, the gate of the second transistor Q5 is connected in series with the resistor R3, the resistor R4 and the first capacitor C4 are connected in series between the gate and the emitter of the second transistor Q5, and a series resistor R2 and R4 are added. This resistor can ensure that the IGBT can be turned on normally and stably, and can also suppress the parasitic oscillation of the IGBT during short circuit. By setting the resistor, the same function of a complex circuit can be achieved, the circuit cost is reduced, and the stability of the IGBT is improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:
[0015] Figure 1 The utility model is a schematic diagram of a circuit for eliminating IGBT short-circuit oscillation. DETAILED DESCRIPTION
[0016] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.
[0017] The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
[0018] Reference Figure 1 , shows a schematic diagram of a circuit for eliminating IGBT short-circuit oscillation according to an embodiment of the utility model, comprising:
[0019] Resistor R1, resistor R3, resistor R2, resistor R4, a first transistor Q3, a second transistor Q5, a first capacitor C3, and a second capacitor C4; the gate of the first transistor Q3 is connected in series with the resistor R1, the resistor R2 and the first capacitor C3 are connected in series between the gate and the emitter of the first transistor Q3, the emitter of the first transistor Q3 is connected to the gate of the second transistor Q5, the gate of the second transistor Q5 is connected in series with the resistor R3, and the resistor R4 and the first capacitor C4 are connected in series between the gate and the emitter of the second transistor Q5.
[0020] The first transistor Q3 includes an insulated gate bipolar transistor, and the second transistor Q5 includes an insulated gate bipolar transistor.
[0021] Further applied to the embodiment of the utility model, the circuit includes a power supply DC, and the collector of the first transistor Q3 and the emitter of the second transistor Q5 are respectively connected to the first output terminal and the second output terminal of the power supply DC. Specifically, the collector of the first transistor Q3 can be connected to the positive electrode of the power supply DC, and the emitter of the second transistor Q5 can be connected to the negative electrode of the power supply DC.
[0022] In the embodiment of the utility model, the emitter of the second transistor Q5 is grounded.
[0023] exist Figure 1In the circuit, when the lower IGBT device of the half bridge, i.e., the second transistor Q5, is turned on, a very high dvdt voltage change will occur on the upper IGBT device, i.e., the first transistor Q3, and the diode. This will cause a displacement current icg to flow, charging the parasitic capacitor CCG of the upper IGBT Q3. Capacitors CCG and CGE form a capacitive voltage divider. The current icg flows through the Miller capacitor, the series resistor, CGE, and the DC bus. If the voltage drop on the gate resistor exceeds the threshold voltage of the IGBT, a parasitic turn-on will occur. As the chip temperature rises, the rated gate drive threshold voltage decreases, which means that under the same voltage, it will be easier to turn on at this time, thus forming a parasitic turn-on.
[0024] In the embodiment of the utility model, a capacitor is added between the gate and the emitter to shunt the Miller current. Adding a capacitor between the gate and the emitter can affect the switching behavior. The capacitor can absorb the additional charge from the Miller capacitor. Since the total input capacitance of the IGBT is equal to CGE, the influence of the Miller capacitance on the parasitic conduction is reduced.
[0025] The advantage of the embodiment of the utility model is that a series resistor R2 and R4 are added. This resistor can ensure that the IGBT can be turned on normally and stably, and can also suppress the parasitic oscillation of the IGBT when it is short-circuited. By setting the resistor, the same function of a complex circuit can be achieved, reducing the circuit cost.
[0026] In another specific implementation, the circuit for eliminating IGBT short-circuit oscillation may include adding a negative voltage drive circuit, or adding an active Miller clamp circuit to replace the above circuit solution, which can also achieve the corresponding function, but the cost will increase.
[0027] In the above description of this specification, unless otherwise clearly specified and limited, the terms "fixed", "installed", "connected" or "connected" should be understood in a broad sense. For example, with regard to the term "connection", it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. Therefore, unless otherwise clearly defined in this specification, those skilled in the art can understand the specific meanings of the above terms in this utility model according to the specific circumstances.
[0028] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", "center", "longitudinal", "lateral", "clockwise" or "counterclockwise", etc., which indicate the orientation or position relationship, are based on the orientation or position relationship shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the utility model and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operate in a specific orientation. Therefore, the above-mentioned orientation or position relationship terms cannot be understood or interpreted as limitations on the scheme of the utility model.
[0029] In addition, the terms "first" or "second" used in this specification to refer to numbers or ordinals are only used for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this specification, the meaning of "plurality" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.
[0030] Although this specification has shown and described a plurality of embodiments of the utility model, it is obvious to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will think of many changes, modifications and alternatives without departing from the idea and spirit of the utility model. It should be understood that in the process of practicing the utility model, various alternatives to the embodiments of the utility model described herein may be adopted. The attached claims are intended to define the scope of protection of the utility model, and therefore cover the modular composition, equivalent or alternatives within the scope of these claims.
Claims
1. A circuit for eliminating IGBT short-circuit oscillation, characterized in that: include: Resistor R1, resistor R3, resistor R2, resistor R4, first transistor Q3, second transistor Q5, first capacitor C3, second capacitor C4; The gate of the first transistor Q3 is connected in series with the resistor R1, the resistor R2 and the first capacitor C3 are connected in series between the gate and the emitter of the first transistor Q3, the emitter of the first transistor Q3 is connected to the gate of the second transistor Q5, the gate of the second transistor Q5 is connected in series with the resistor R3, and the resistor R4 and the first capacitor C4 are connected in series between the gate and the emitter of the second transistor Q5.
2. The circuit for eliminating IGBT short-circuit oscillation according to claim 1, characterized in that: The first transistor Q3 comprises an insulated gate bipolar transistor.
3. The circuit for eliminating IGBT short-circuit oscillation according to claim 1, characterized in that: The second transistor Q5 includes an insulated gate bipolar transistor.
4. The circuit for eliminating IGBT short-circuit oscillation according to claim 1, characterized in that: The circuit includes a power source DC, and the collector of the first transistor Q3 and the emitter of the second transistor Q5 are connected to a first output terminal and a second output terminal of the power source DC respectively.
5. The circuit for eliminating IGBT short-circuit oscillation according to claim 1, characterized in that: The emitter of the second transistor Q5 is grounded.