Common mode voltage reduction schemes for voltage source converters in an autonomous microgrid

Voltage-sourced converter (VSC) is becoming the key element in the operation of microgrids due to its high performance and efficiency. However, implementing VSC may generate some issues to the microgrid such as high common mode voltage (CMV). CMV could produce high leakage current and bearing failure in case of motor load. This paper develops a solution for high CMV using reduced CMV-PWM algorithm to control of VSC with interfaced source in an autonomous microgrid. It also investigates the performance of V/F controller of VSC when reduced CMV-PWM technique is applied. The following approaches are implemented to provide detailed procedures for reducing CMV of VSC. First, a microgrid with V/F vector control is illustrated. Second, a reduced CMV-PWM method is investigated and compared with conventional PWM technique. Finally, a microgrid is modeled and simulated in PSCAD/EMTDC to validate reduced CMV-PWM technique.