Active clamp voltage stress suppression circuit, method and drive circuit for power switch

Abstract

Disclosed in the present invention are an active clamp voltage stress suppression circuit, method and driving circuit for a power switch, wherein an active clamp circuit is connected between an input terminal and control terminal of a power switch, and a suppression circuit comprises: a detection module that is used for detecting whether the power switch triggers an active clamp; an execution module that is disposed in a driving path of the power switch, and that is used for cutting off the driving path when the detection module detects that the active clamp is triggered. The present invention detects whether the power switch triggers the active clamp, and cuts off a current driving path of the power switch when the detection module detects that the active clamp is triggered, thereby eliminating the bypass effect of the driving path on current of an active clamp injection power switch, and improving the utilization rate of reverse breakdown current of the active clamp circuit. Thus, the clamping effect of the active clamp is improved, heat loss of a transient voltage suppressor (TVS) in the active clamp circuit is reduced, heat loss of the driving circuit is reduced, and the reliability of the active clamp circuit is improved.

Description

Technical field [0001] The invention relates to the field of motor control, in particular to an active clamp voltage stress suppression circuit, method and drive circuit of a power switch. Background technique [0002] IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) is a common power switching device, which is often used in high-voltage and high-current conditions. During the IGBT turn-off process, the induced electromotive force generated on the loop stray inductance is superimposed on the bus voltage, causing a large voltage stress between the collector and emitter of the IGBT. Active clamping technology detects the voltage between the collector and emitter of the IGBT through TVS (Transient Voltage Suppressor, also known as transient suppression diode). When the voltage exceeds the breakdown voltage of the TVS, the TVS is reversely broken down, resulting in The breakdown current flows to the gate of the IGBT, which can slow down the decline of the ...

AI Technical Summary

Problems solved by technology

[0005] It can be seen from the above that due to the bypass effect of the drive circuit in the prior art, the current injected into the gate of the IGBT by TVS reverse breakdown is lost, which greatly affects the effect of active clamping and the service life of TVS

Images