Sliding mode control for three-phase unity power factor rectifier with vector operation

This paper present a sliding mode control operating at fixed switching frequency for a three-phase unity power factor rectifier using the vector operation technique. The proposed method allows to find a large-signal converter dynamic model in order to transform a tree-phase system into two decoupled subsystems. With this technique only two sliding-mode controllers are needed and the neutral point voltage influence is removed from the controllers dynamics. A fast output-voltage control is used which avoids output-voltage variations when a sudden change in the load appears. Besides a variable hysteresis band control is used in order to fix the switching frequency of the sliding-mode controllers. Experimental results are provided using a fully-digital control system in order to validate the theoretical predictions.