Monitoring and control of the protection system of electric drives with the method of pulse-width modulation

This article deals with increasing the stability of power supply by improving the protection and control of electric drives using the pulsewidth modulation (PWM) method. The method consists in the formation of periodic series of pulses of a certain duty cycle, creating separately positive and negative half-waves of the current sinusoid in the motor windings. The PWM method of base vectors (vector modulation) consists in switching between several pre-selected states of the inverter, each of which corresponds to a certain spatial position of the resulting voltage vector applied to the engine. In the PWM method, each phase zone is divided into 3 subzones with its own duty cycle. This method is suitable for both three-stage inverter and six-stage inverter. It can be seen in the work that the quality of the resulting current depends not only on the number of subzones for the formation of base vectors, but also on the number of voltage pulses per subzone. The more pulses fall on the formation subzone, the cleaner the resulting current curve is.

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