Modified Space Vector Modulation and Voltage Balancing of Multiphase Neutral Point Clamped Rectifier

This study describes a control approach that balances the DC-Link capacitors voltage in a multiphase neutral-point-clamped (NPC) rectifier by applying optimized switching sequences. First a modified multiphase space vector modulation (SVM) control scheme has been proposed, which reduce the voltage fluctuations across the DC-Link capacitors. Based on the proposed SVM, each sector and its regions have different levels of effectiveness for small and medium vectors for the same switching state, which results in a better understanding of the problem. In the next step, a voltage balancing algorithm is presented and unified with the proposed space vector modulation in order to make sure that the best switching sequence with the least amount of energy deviation is chosen. The performance of the presented controller is evaluated through a comprehensive series of simulations.