Self-synchronization operation of global synchronous pulsewidth modulation with communication fault tolerant and simplified calculation capabilities

Abstract

The distributed inverters are generally integrated into power grid without switching sequence coordinated control capability since they are equipped with their own micro controllers to command the output quantities. The switching ripples of all distributed inverters will then be randomly accumulated at the point of common coupling. The recently proposed global synchronous pulsewidth modulation (GSPWM) method however can significantly attenuate the accumulated switching ripples by periodically coordinating the distributed inverters at low synchronization frequency. GSPWM can be applied to reduce filter or switching frequency of coordinated inverters under high reliable communication system. While to increase the system robustness, this paper deeply analyzes the performance of GSPWM when the communication channels fail, especially lose the synchronous signals. And then the self-synchronization method is proposed to avoid the breakdown of GSPWM. Moreover, the self-synchronization operation could benefit to explore a simplified method to calculate the sending frequency of synchronous signals, which can greatly release the calculation burden. Finally, experimental results are presented to verify the performance of the proposed self-synchronization operation of GSWPM.