A Wireless-Communication Based Circulating-Current Controller for Parallel Three-Phase Inverters

We propose a circulating-current control scheme for a two-module parallel three-phase voltage-source inverter (VSI) that can be applied in general to any space-vector modulation (SVM) scheme and experimentally demonstrate its effectiveness for two commonly used SVM schemes (symmetrical SVM and bus-clamped SVM). The proposed control strategy relies on radio-frequency (RF) based wireless communication to exchange circulating-current information among the parallel VSIs. We also investigate the impacts of time delay due to wireless communication on the stability of the parallel VSI. Thus, by transmitting the circulating-current information over a wireless medium, we attain improved VSI performance, while also ensuring that the issues of survivability, robustness, self-configuration and reconfigurability of the system are not compromised. In general, such a control scheme may lead to more redundant control implementation of distributed power systems and could also be used as a back-up for wire-based control schemes to provide fault tolerance.