An Adaptive Gate Current Modulator based on Fuzzy PID for Voltage Equalization in Series Connected IGBTs

This paper firstly proposes a gate current modulator (GCM) based on fuzzy PID for voltage equalization in series connected IGBTs. A MOSFET is introduced as a variable resistance that paralleled with gate resistor. The gate of the MOSFET is controlled initially by fuzzy PID, thus the resistance of MOSFET is adjusted real-timely adapting to operation condition. The fuzzy PID is configured with hardware algorithm. The simulation results in buck circuit with four IGBTs series connected show that the peak of voltage unbalance ratio of GCM is 3.78% while that of the snubbers is 25.1 %, illustrating ten times reduction.