Multi-Level Synthesis Gate Voltage Active Control Technology for Optimizing IGBT Switching Characteristics

Compared with the conducting and blocking steady-state processes, the voltage and current stress of insulated gate bipolar transistor (IGBT) become very higher in the turning-on and turning-off transient processes, and the instantaneous power loss increases significantly. The switching transient conditions greatly affect the reliability and stability of IGBT devices and power converters. During the IGBT turning-on process, the reverse recovery of the symmetrical bridge arm anti-paralleled diode can cause additional turn-on loss and current peak overshoot. The gate voltage active control technology can effectively suppress current spike and reduce turn-on loss in the period from the initial opening time to Miller platform. The multi-level synthesis technology can adjust the gate voltage waveform and produce depression or bulge in the normal driving voltage waveform for a certain time. In this article, the sensitive parameters of gate voltage active control, which affect the current overshoot, and turn-on loss of IGBT are studied based on the theoretical calculation and mathematical model. A multi-level synthesis gate voltage active control technology is proposed according to the principle of gate voltage active control. The relationship among the acting voltage amplitude, execution time, current peak, and switching loss is studied. Considering the actual application conditions, the optimized active control scheme of gate voltage is designed. Finally, the switching characteristics test is carried out, the results verify that the proposed control technology can effectively reduce the current overshoot and turn-on loss in comparison with the conventional schemes.