Control for AC motor having parallel sets of three-phase windings with only one current sensor per set

Abstract

A control for an AC motor has first and second sets of three-phase stator windings wound physically in parallel and a three-phase inverter for each set. A first current sensor is responsive to a first phase current of the first set of three-phase stator windings; and a second current sensor is responsive to a phase current of the second set of three-phase windings other than that corresponding to the first phase current of the first set of three-phase windings. The control is responsive to signals from the first and second current sensors to generate a set of motor phase voltage control signals, which are provided to first and second three-phase inverters connected across a source of DC electric power. The first three-phase inverter uses semiconductor switches responsive to the set of motor phase voltage control signals to generate operating voltages in the first set of three-phase windings; and the second three-phase inverter uses semiconductor switches responsive to the set of motor phase voltage control signals to generate operating voltages in the second set of three-phase windings. The control thus eliminates two current sensors, two current controllers and a PWM pulse generator of the prior art for a reduction in cost and improvement in reliability.

Dependencies are inferred from the claim text.