Hybrid control of three-phase current source rectifiers

This paper presents a hybrid control strategy to regulate the active power and the input displacement power factor in a three-phase rectifier with zero steady state error. Particularly, it uses a predictive approach in combination with a linear PI controller. The predictive portion takes care of the non-linear, multi-variable, and coupled behavior of the topology. This is possible due to the limited number of valid positions of the switches and the deterministic model of the structure that allows the representation by means of a discrete algorithm. However, parameter variations and the ineludible approximations of the discrete model, makes the overall performance far from being the optimum expected in both dynamic and static conditions. This justifies the use of the additional linear PI controller in order to operate with zero steady state error. The resulting system becomes a hybrid approach and the results show an easy strategy to be implemented in a digital system with high overall performance.