SRF based modeling and control of cascaded multilevel active rectifier with uniform DC-buses

Cascaded H-bridge (CHB) multilevel active rectifier system envisage attractive alternative for conventional method of active rectification and finds application in traction drive and locomotives. Further CHB structure can be utilize of high voltage transformer less rectification. Availability of multiple DC buses in CHB, needs DC bus regulation at each level. It becomes a challenging task in CHB due to interdependent control of each H-bridge. It is therefore proper control algorithm has to be designed for effective regulation and fast response. In view of this single phase synchronous reference frame (SRF) theory based voltage controlled phase shifted PWM controller has been modeled for active rectification with unity power factor operation. MATLAB based simulation results shows the efficient working of CHB multilevel active rectifier with proposed control algorithms and its effectiveness is verified by changing the loading conditions.