In the last year model predictive control strategy has emerged as a good alternative for the control of power converters. This research proposes a new model -based predictive control strategy for a voltage source inverter, operating at variable and fixed switching frequency, with the objective of comparing the performance of the control algorithm and the output variables. The experimental results show the benefits of predictive control and the superiority of fixed frequency control strategies instead of the variable switching frequency. Based on the total harmonic distortion (THD) and the absolute error, we can prove that better results are obtained by forcing the converter to commutate at fixed frequency.