The SVPWM fast algorithm for three-phase inverters

In this paper, a zero-vector distribution variable k(1), which changes from zero to one, is introduced. The continuous SVPWM is generated when 0<k(1)<1, and several typical kinds of discontinuous SVPWM are generated when k(1)=1 or 0. In particular, a unified SVPWM fast algorithm suitable for the digital implementation of all continuous and discontinuous SVPWM strategies is proposed according to the relationship between carrier-based PWM and SVPWM methods. Compared with the SVPWM conventional algorithm, the proposed algorithm can be more easily implemented with a microprocessor because it calculates the actual gating times for each inverter leg directly using three-phase reference voltages and needn't complex coordinate transformations, trigonometric function calculations, sector number identification, and the recombination of actual gating times. At last, the influence of the zero-vector distribution factor and modulation index on the voltage harmonic characteristics of all SVPWM strategies is investigated. The simulation and experimental results show that the proposed method is valid and feasible.