Series and Shunt Compensators for Power Quality Compensation

This paper presents series and shunt compensators based on neutral point diode clamp topology for power quality compensation. The function of the series compensator is to prevent the load voltage variation against the abnormal voltage disturbance, such as voltage sag and voltage swell at the utility side. The feature of the shunt compensator will supply or draw active current from the system to keep the DC bus voltage constant and improve the current quality at the utility side. The neutral point clamp inverter has less voltage stress of power semiconductor compared with the voltage stress of switching devices in the conventional full-bridge inverter. Experiments based on a laboratory prototype are presented to verify the effectiveness and validity of the proposed control scheme