New medium voltage drive systems using three-level neutral point clamped inverter with high voltage IGBT

This paper presents a new range of medium voltage motor drives with a three-level neutral point clamped inverter using high-voltage IGBTs. Different line side converters are available, including a twelve pulse diode rectifier and an active front end converter in the same configuration as the inverter. Innovative features of the drive include series-connection of high-voltage IGBTs and a novel isolated voltage and current sensing system. The motor control is based on field-oriented vector control and an optimized PWM modulator, so that switching losses and current harmonics are minimized. The combination of the three-level neutral point clamped inverter, with motor insulation taking inverter operation into account, results in an efficiency optimized (filterless) drive system.