Analysis of three phase controlled rectifier with current active filter

The subject of this paper is the analysis of three-phase rectifiers with active filters. The new concept of three-phase controlled rectifier input current filtering is proposed and analysed. A modified technique for input current and output voltage control are presented. The simple hysteresis-band current control PWM method ensures a nearly sinusoidal input current with low harmonic content. Applying an additional active filter in parallel to the main circuit of the rectifier, much better quality of input current is obtained. This additional filter is able to operate with much higher switching frequency and low power, and in this way high harmonic content is significantly reduced and shifted to much higher frequencies. A voltage control loop yields good output performance.