Active Clamping with Nonlinear Gate Voltage Control Unit

Inhalt:
Active clamping is an effective method to solve the problem of turn-off voltage stress of fully controlled power semiconductor devices, such as IGBT. However, in the past researches and applications, the development of this technology focused on reducing the voltage spike of IGBT itself. In fact, the voltage spike of the anti-parallel diode in IGBT module also needs to be considered, and this is a bigger challenge for active clamping. This paper proposes a nonlinear gate voltage control unit (NLU), with which active clamping could effectively suppress the voltage spike both during IGBT turn-off and during its anti-parallel diode turn-off. The performance is verified by experiments.