Optimal algorithms of multiphase pulse width modulation based on load current dispersion

Aim. Development of algorithms for multiphase pulse width modulation in the converter-to-electric motor system that are optimal in terms of the load current dispersion in the load. Materials and Methods. To study the processes of multiphase pulse width modulation in frequency control of electric drives in the converter-to-electric motor system, methods of electrical circuit theory are used; the proposed algorithms are illustrated by figures and can be implemented in the MATLAB software environment. Results. We considered the process of multiphase pulse width modulation in the converter-to-electric motor system. We demonstrated that full-phase and non-full-phase pulse width modulation algorithms can be used to minimize the number of switching operations of voltage switch converter keys. We analyzed expressions for modulating functions of multiphase voltages of half-bridges of voltage switch converters. We produced an expression for the local dispersion of the load current of a multiphase bridge circuit. We found numerical values of the pulse displacement coefficients which make it possible to obtain a minimum value of local current dispersion for cases of full-phase and non-full-phase multiphase pulse width modulation. We produced an expression for the optimal pre-modulation function, which allows us to avoid over-modulation at any values of the amplitude coefficient under given restrictions. We found an expression for the cutoff modulation coefficient of a multiphase bridge for sinusoidal modulating voltage functions. Conclusion. The results can be used for development of control algorithms for multiphase voltage switch converters in automated electric drive systems.