Efficient predictive current control technique for multilevel voltage source inverters

In this paper a predictive current control technique for multilevel voltage source inverters (MVSI) is presented. The proposed method can be applied to any multilevel inverter for high-voltage high-power applications. Here, it is applied to a four-level neutral-point diode clamped voltage source inverter (NPDCVSI). The inverter is considered as a non-linear system with its thirty seven discrete space voltage vectors. The proposed controller predicts the load current for all voltage vectors generated by the inverter. The current error for each voltage vector is calculated and the vector that ensures the smallest value of current error is selected as the inverter voltage vector for the next sampling period. The method allows optimum reference current tracking for all operating conditions under low current harmonic distortion as a result of many voltage vectors that participate in the control process. Furthermore, the proposed control ensures fast dynamic response and decoupling effect between the load current components. Simulation and experimental results verify the effectiveness of the predictive current controller