Control of the switching transients of IGBT series strings byhigh-performance drive units

In the field of power electronics, the use of series-connected insulated gate devices, such as insulated gate bipolar transistors or power MOSFETs, is interesting in order to obtain fast and efficient power switches in medium-range power converters. In this kind of application, the control of the voltage sharing across the series strings of devices is an important aspect to be considered. The proposed technique allows obtaining safe commutations of the switches by simple and effective control circuits acting on the gate side of the power devices. In particular, the gate drive units are arranged in order to ensure good performance during the switching transients, while preventing overvoltage peaks on the devices. Both the design criteria and analysis of the control circuit are developed. Several experimental tests are reported in order to demonstrate the validity and correctness of the proposed approach