Robust Tracking Control for Output Voltage of UPS Inverter

This paper presents a discrete integral sliding mode control scheme with time-delay compensation for the output voltage regulation of an uninterruptible power supply (UPS) inverter. Since the inverter is subject to the parameter variation and the load disturbance and the time delay is introduced due to the adoption of digital control scheme, the controller is required to reject the disturbance as well as the influence of the time delay. This paper analyzes and models the discrete single-phase UPS inverter with time delay. To enhance the robustness of the inverter the discrete integral sliding mode control scheme is proposed. An integral controller is added to improve the steady performance of the controller and the time-delay compensation is considered to eliminate the influence of the time delay. The inverter has shown its excellent voltage tracking performance through the simulation results and the effectiveness of the scheme is verified.