Active Voltage Control of IGBTs for High Power Applications

The operation of an insulated gate bipolar transistor (IGBT) in its active region is a well established technique for withstanding short circuits and also for dv/dt control. In this paper, we exploit the active behavior of the IGBT, applying a voltage feedback loop to the IGBT to control its switching. It is shown that adding a bias to the demand reference waveform shifts the IGBT into the active region and permits wide bandwidth operation over most of the switching transient. The operation of the IGBT is reported in detail, making reference to a selection of experimental waveforms for 400-A, 1700-V capsule IGBTs. The implementation required for control of such large IGBT modules and capsule devices for high power applications is described and discussed. It is concluded that the active voltage control method allows the operation of high power IGBT circuits to be closely defined.