Investigation of IGBT switching energy loss and peak overvoltage using digital active gate drives

This paper presents an experimental investigation of the switching energy loss and peak overvoltage occurring in a half-bridge Insulated Gate Bipolar Transistor (IGBT) converter which is switched using an Active Gate Drive. A range of voltage profiles is systematically applied to the IGBT gate and the resulting switching behaviour is measured to obtain the switching energy loss and peak overvoltage for each gate profile. The experimental apparatus which allows different gate waveforms to be tested is described, and the minimum achievable switching loss for a set overvoltage limit is found for turn-on using gate voltage waveforms of increasing complexity. A reduction in turn-on switching energy loss of 24% is achieved with the most sophisticated gate voltage waveform tested compared to a simple voltage ramp waveform. Turn-off overvoltage is controlled when using more complex gate waveforms whereas simpler voltage ramping fails to influence the turn-off voltage overshoot.