Wide Correction Range Three-Level Dynamic Voltage Corrector

The dynamic sag correctors are used at the sensitive load terminals of the centralized power supply in order to avoid the grid voltage sag. This paper focuses on the correction of grid voltage swell/sag in large range and the quality of compensated voltage. A wide correction range dynamic voltage corrector is proposed for solving above problems with low cost. The operation principle, the voltage corrector range, and the design consideration of key parameters are analyzed. The increase of dc-link voltage broadens the voltage sag correction range, while the realization of the voltage swell correction benefits from the bidirectional energy flow. The simulation and experimental results verify the validity of the theoretical analysis. A prototype which applies to the centralized power supply-based ground power unit for aircrafts has been developed. It is characterized as small size, light weight, high compensation efficiency, good dynamic performance, and high quality of output waveform.