Development of a 7-level medium voltage inverter system with PWM converter for regenerating operation

摘要

The 3300[V], 2[MVA] 7-level inverter system with PWM Converters as an active front-end is introduced. The multi-level inverter system operates in a 4-quadrant and in a nearly unit displacement power factor and each PWM converter operates with phase-shifting by 40 degrees to improve overall AC side harmonic performance. A current controller of PWM converter has feed forward compensation to increase dynamic response and reduce capacitors. PSC(Phase Shifted Carrier) PWM is used to control the inverter module. Vector control algorithm is implemented to control the instantaneous torque and speed of an induction motor. The experimental waveforms are also presented to verify the proposed method and performance of the developed system.