Research On Control Technology Of Single Phase UPS Inverter System

Uninterruptible power supply(UPS) are widely used which can provide continuous and high quality AC power to electrical equipment. As a core power part of UPS, performance of the inverter system directly affects the quality of UPS output AC power supply.Therefore, it has important practical significance and application value to study on inverter system to design an uninterruptible power supply.This paper is committed to the control technology's study of single-phase UPS inverter system for its high-quality AC power output, including the SPWM control strategy of the inverter bridge and a double closed-loop control strategy under open-loop control which is based on the inductor current and capacitor voltage output of the inverter system. The inverter system has good d ynamic characteristics under this control strategy, but the PI control is a kind of differential control, and has much periodic disturbance signals in the inverter system. So repetitivecontrol is introduced based on the double closed-loop control, that is, the improved repetitive control strategy is designed in the controller of the inverter system to make the system obtain better stable performance. And this paper also discusses pure software solution for the bias magnetic in the output of the inverter system without isolation transformer and finally presented a design scheme of a FPGA-based digital single-phase UPS inverter system depend on the result of simulation.A new compound control algorithm, SPWM control strategy as the underlying driver algorithm, double closed-loop control plus repetitive control as the upper control has been proposed here, and the result of experiment show its application can help the single-phase UPS inverter system output high qualit y AC power supply.