Algorithm of three-phase pulse width modulation with limitation on power loss in electronic switches in the converter–electric motor system

The process of pulse width modulation (PWM) in a converter–electric motor system is considered. It is shown that for the synthesis of converter control systems, along with сontinuous PWMs (CPWM), discontinuous PWMs (DPWM) are also used, the advantage of which is a relatively low number of switching of the key elements of the converter. The algorithm of three-phase PWM, optimal by the criterion of current dispersion in the load, is considered, taking into account the limitations on power loss in electronic switches. Expressions for the integral dispersion of the load current are obtained. For a comparative evaluation of the algorithms, a criterion is formulated in the form of efficiency coefficients for сontinuous PWM and discontinuous PWM methods. The tolerance range of the appropriate modulation with a minimum number of commutations in the space of the amplitude coefficient and the relative frequency of the nominal modulation is obtained. The dependences of the efficiency coefficient of the discontinuous PWM algorithm at an increased modulation frequency are obtained depending on the amplitude coefficient and the relative modulation have been established.

Authors: A. V. Saushev, I. V. Belousov, V. F. Samoseiko

Direction: Electrical Engineering

Keywords: pulse width modulation, full-phase and incomplete-phase algorithms, converter–electric motor system, current dispersion in the load, evaluation of modulation efficiency

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