Line-interactive DVR using multi-level H-bridge inverter

The interest in power quality has become a hot issue. The equipment causes voltage disturbance and has become more sensitive to the voltage disturbance. This paper deals with 5-level H-bridge line-interactive dynamic voltage restorer (LIDVR) system. The LIDVR has following advantages in comparison with the DVR with series injection transformer. It has the power factor near to unity under normal source voltage, can compensate the harmonic current of the load and the instant interruption, and has the fast response. First, the construction, the operation mode and algebraic modeling of LIDVR are reviewed. Then a voltage controller is proposed to get sinusoidal PCC (point of common coupling) voltage with constant amplitude. To find PWM method suitable for multi-level H-bridge converter, two PWM methods are compared and analyzed. Finally, simulation results verify the proposed 5-level H-bridge LIDVR system.