Study and control of 5-level PWM rectifier-5-level NPC active power filter cascade using feedback control and redundant vectors

摘要

The purpose of this paper is to develop a control andregulation method for the input DC voltages of a 5-level neutral pointclamping (NPC) active power filter (APF). This APF is applied for theenhancement of medium-voltage network power quality by compensation ofharmonic currents produced by an induction motor speed variator. Inthe first part, the authors present a topology of a 5-level NPCvoltage source inverter and its simplified space vector pulse widthmodulation (SVPWM) control strategy. In the second part, the controlstrategy of the 5-level pulse width modulation current rectifier ispresented. In the third part, to remedy to instability problem of theinput DC voltages of the APF, the authors propose the feedback controlof the 5-level rectifier associated with a simplified SVPWM with theredundant vectors method for the 5-level APF. After that, the slidingmode regulator used to control the APF is developed. The applicationof the proposed control algorithm offers the possibility ofstabilizing the DC voltages of the APF. The stable DC bus supplyassociated with the sliding regulator of the APF allows the obtainment of low-harmonic content network currents with unity power factor. The instability problem associated with the use of the multilevel APF is solved. The obtained results are full of promise for the use of the multilevel APF in medium-voltage and high-power applications.