Research of high voltage DC uninterrupted power system

WANG Kan, LI Weichen, YANG Bo, HE Xiangning

(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: Aiming at solving the problem of complicated structure, low efficiency, low reliability of the traditional UPS, a high voltage DC UPS was proposed. About the circuit structure, by using the T type threelevel rectification circuit as the frontstage circuit of the power supply, the input power factor and THD of input current was improved. By using inputseries and outputparallel fullbridge converter as the poststage circuit, which was applied the interleaving parallel technique, the output current ripple was depressed. By using a new feedforward control of the load current when the load fluctuated violently, the dynamic performance was improved and the ripple of output voltage was depressed. The results indicate that the maximum efficiency of the power supply is 96%. The recovery time is less than 200μs and the fluctuation of the output voltage is less than 5% when the load fluctuates violently. It has fast dynamic response and good output characteristic.

Key words: high direct voltage UPS; high efficiency; high reliability; loadcurrent feedforward control