Hybrid modulation based on SHEPWM and SVPWM

A hybrid modulation algorithm based on the space-vector PWM and selective harmonic elimination PWM is proposed in the article. This algorithm will reduce the losses in the power converter that occur at space-vector PWM switching by reducing the number of these switching at selective harmonic elimination PWM. The main requirements for the hybrid algorithm were formulated. The paper was focused on the consideration of possible variants of changing the algorithms of the space-vector PWM and selective harmonic elimination PWM depending on the states of the semiconductor switches in the power converter circuit. Four possible variants were identified for a three-level converter, two of which satisfy the requirements of the hybrid algorithm. The results of simulation in the Matlab/Simulink program show minimization in the number of switching semiconductor modules of the power converter. The practical use of the proposed hybrid modulation algorithm has able to increase the efficiency and improve the quality of converted energy. The proposed hybrid method of modulation will be most effective in the high power application, where medium voltage three-level converters are used.