Feedback Control of Five-Level PWM Rectifier: Application to the Stabilization of DC Voltages of Five-Level NPC Active Power Filter

Abstract

The purpose of this paper is to develop a control and regulation method of input DC voltages of five-level Neutral Point Clamping (NPC) Active Power Filter (APF). This APF is applied for the enhancement of 5,5kV (ph-ph) network power quality by compensation of harmonic currents produced by an induction motor speed variator. In the first part, the authors present a topology of five-level NPC Voltage Source Inverter (VSI), and then, they propose a model of this converter and its PWM control strategy. In the second part, the control strategy of five-level PWM current rectifier is presented. In the third part, to remedy to instability problem of the input DC voltages of the APF, the authors propose feedback control of the five-level PWM rectifier followed by clamping bridge filter. After that, the sliding mode regulator used to control the APF is developed. The application of the proposed feedback control algorithm to the studied cascade offers the possibility of stabilizing the DC voltages of APF. Stable DC bus supply associated with sliding regulator of APF allows getting low-harmonic content network currents with unity power factor. In all over, the instability problem associated with use of multilevel APF is solved. The obtained results are full of promise to use the multilevel APF in high voltage and great power applications