A Novel Dynamic Voltage Regulator with a Multi-level AC/AC Converter

This article proposed a novel topology of dynamic voltage regulator using transformer and PWM multi-level AC/AC converter. In this paper for finding the best value of duty ratio for switches to minimize the THD, the GA algorithm has been used and THD output voltage is assumed to be fitness function. The proposed voltage regulator employs multi-level AC/AC converter to generate compensation voltage and uses the transformer to isolate the power converter from the load. The proposed converter provides a highly sinusoidal and regulated output voltage with a simple topology. When input voltage under-voltage and overvoltage occur, the output voltage can be regulated by changing the duty ratio of the PWM control signals. The transformer is connected in series with the load. Thus, the load voltage can be kept stable when input voltage fluctuations occur. For this purpose, PI controller has been designed to perform the close-loop control. The proposed converter and control strategy present the advantages of fast dynamic response and effective compensation to the voltage fluctuations. Simulations are made to investigate the performances of the proposed converter. The simulation results show that the designed voltage regulator has fast transient response, and can suppress the load voltage fluctuations effectively.