Inverter system with enhanced common source inductance generated at gate driver

Abstract

A multiphase inverter for an electric vehicle drive has a plurality of drivers to provide drive signals to respective gate loops of upper and lower transistors in the phase legs. A transformer has a secondary winding in a first gate loop of a first transistor in one phase leg and a primary winding connecting a Kelvin-emitter of the first transistor to a Kelvin-emitter of a second transistor in the other phase leg. Switching transients of transistors are shortened because when gate signal is toggled to change a conduction state of a transistor in a first phase leg, a rate of current change in the first leg is sensed in a transformer primary winding connected across a stray inductance of the first leg. A voltage proportional to the sensed rate is added to the gate signal via a transformer secondary winding, thereby increasing a common source inductance of the transistor.