Predictive frequency spectrum shaping of currents in a three phase inverter

Model predictive control is a very intuitive, simple, and flexible control strategy that can be applied to any converter topology achieving a wide variety of control objectives. However, one of the disadvantages of this control method is the variable switching frequency of the gate signals, which increase the losses and can generate resonances. In this paper, a simple and powerful method to shape the switching frequency spectrum of the gate signals of the converter is proposed. The proposed method is very flexible allowing to avoid, displace or concentrate the frequency spectrum in an specific range of switching frequencies. The method is based on a virtual filter which is simulated inside the digital processor and its output is evaluated, similarly to the load model, for each one of the possible switching states, incorporating later this information to the cost function. Simulation results shows the validity and performance of the proposed control.