Improved techniques of restrained search predictive control for multiphase drives

Predictive control is becoming an alternative to standard vector control or direct torque control in electrical drives due to its fast torque response and design flexibility. In multiphase drives, where the complexity of the modulation techniques and control schemes is higher, the predictive control has proved to be a promising alternative. The main shortcoming of the standard predictive control (SPC) in multiphase drives is the high computational cost caused by the increased number of switching state possibilities. This work proposes a restrained search predictive control (RSPC) where some switching states are discarded by imposing several restrictions. The steady and transient states are explored, also examining the unbalance in the switching frequency of the voltage source inverter (VSI) legs and the effect of allowing submodulation. The advantages of the proposed control are discussed and the viability is confirmed by simulation.