A Closed-loop Global Synchronous PWM Method for Immunizing Parameters Uncertainty in Distributed Parallel-Connected VSIs

This paper proposes a closed-loop global synchronous pulse width modulation (CL-GSPWM) method for eliminating the switching harmonics in parallel-connected voltage source inverters (VSIs) with the immunity of parameters' uncertainty. In specific, the measured total current at PCC will periodically sent to the Global Synchronous Unit (GSU) as feedback signal using the low-cost narrow-band communication system. Then, the GSU will correct the calculated optimal phase shift angles among PWM carriers to intentionally minimize the total current harmonics. Doing so, the CL-GSPWM can achieve the expected performance even under the severe parameters' variation. The experimental results verified the proposed CL-GSPWM method.