Base/gate drive suppression of inactive power devices of a voltage-fed inverter and precision synthesis of AC voltage and DC link current waves

A control principle that suppresses the base/gate drive of inactive power semiconductor devices of a voltage-fed inverter that supplies lagging reactive load is described. The principle is utilized to fabricate precisely the inverter output AC voltage waves from the information of DC link voltage, base/gate drive logic waves, and estimated drops across the conducting devices. The estimation of DC link current from the drive logic waves and AC phase currents is also described. A complete control circuit for base/gate drive suppression and precision estimation circuits for inverter AC voltages and DC link currents were designed and tested using a commercial three-phase transistor inverter induction motor drive