Research on the control of zero-sequence circulating current of paralleled inverters based on Dual-carrier-modulator and PR control

To suppress zero-sequence circulating current in parallel operating inverters with common DC power supply, this paper proposes a new strategy based on Dual-carrier SVPWM and proportional resonant (PR) control, which use two opposite active vectors instead of zero vectors to suppress the higher frequency circulating current and reduces the lower frequency circulating current by means of zero-sequence circulating current closed-loop control based on PR controller. It has the advantages of high-efficiency usage of DC voltage, needless carrier synchronization and eliminating the circulating current. Simulation experiments verify the strategy´s effectiveness in the two parallel inverters.