Patent ID: 8780594

Claim:
A parallel inverter drive system for driving a motor, comprising: a plurality of inverter drives connected in parallel with each other, each inverter drive comprising: a switch device; a pulse-width modulation controller connected to the switch device for controlling switching operations of the switch device according to a duty cycle signal; and a circulating current suppressor connected to an output end of the switch device and an input end of the pulse-width modulation controller for collecting current information associated with a current of each inverter drive and a summation current of the inverter drives, and generating an index according to collected current information and a desired circulating current quantity and/or a desired zero-sequence current quantity, and respectively generating a zero-sequence voltage for each phase of a three-voltage voltage command of the inverter drive according to the index, the three-voltage voltage command of the inverter drive, and an operating mode of the inverter drive, thereby injecting the zero-sequence voltage into each phase of the three-phase voltage command to generate a corrected three-phase voltage command; wherein the pulse-width modulation controller is configured to generate the duty cycle signal according to the corrected three-phase voltage command.