Development of a three-phase high power factor Multilevel Current-Source Rectifier

In this paper, a three-phase high power factor Multilevel Current-Source Rectifier (MCSR) is developed. The structure of the given MCSR consists of three modules of current-source, three-phase six-valve converters and some sharing-current inductors. The operation characteristics of the MCSR are investigated. In the MCSR, Carrier Phase-Shifted SPWM is used. Harmonic characteristics of the ac input current and the dc output voltage and current are analyzed in detail. It is shown that, many good features can be achieved such as equivalent higher carrier frequency at the ac side of the MCSR even with lower switching frequency. Furthermore, dc output voltage has no low harmonic components, and the power factor of the ac side is easy to control to be unit. A fully digital solution of tri-logic SPWM gating signals for the MCSR is studied based on the DSP and FPGA platform. At last, simulated and experimental results are given to demonstrate the proposition.