Electric drive power converter with low distortion dead-time insertion

Abstract

An electric drive system of an electrified vehicle has a power converter with phase leg switching devices controlled by pulse-width modulation to supply multi-phase AC to an electric traction motor. Dead-time intervals are inserted into gate drive signals for the switching devices without introducing any significant distortion in the output of the converter. A direction of current flow between a phase leg and the motor is detected. When the current direction is positive, lower gate signals for a lower switching device in the phase leg have a delayed rising edge and an advanced falling edge while upper gate signals are unmodified. When the current direction is negative, upper gate signals for an upper switching device in the phase leg have a delayed rising edge and an advanced falling edge while lower gate signals are unmodified.