Classical methods and model predictive control of three-phase inverter with output LC filter for UPS applications

The total harmonic distortion (THD) plays a major role in determining the quality of the inverter output waveform. The use of an inverter with an output LC filter allows for generation of sinusoidal voltages with low harmonic distortion. Several control schemes have been proposed for the control of three-phase inverter. This paper presents a new and simple control scheme using predictive control. The controller uses a discrete-time model of the system to predict the behavior of the output voltage for all possible switching states generated by the inverter. Then, a cost function is used as a criterion for selecting the switching state that will be applied during the next sampling interval. The performance of the proposed predictive control method is compared with hysteresis and pulsewidth modulation control under linear and nonlinear loads. The results show that the predictive method controls very effectively the output voltage and performs very well compared with the classical solutions.