Development of Improved PWM Algorithm of Active Rectifier with Function of Resonant Phenomena Adaptation in Electrical Networks of Medium Voltage

A modern adjustable electric drive of high power, as a rule, is based on synchronous and asynchronous AC motors with frequency converters. Standard solutions for ensuring the electromagnetic compatibility of such electric drives are: the use of active rectifiers with pulse-width modulation, multi-level topology of the frequency converter, multi-pulse rectification schemes, as well as various filters of higher harmonics. However, at the design stage, it is not always possible to take into account all the factors affecting the electromagnetic compatibility of frequency converters with a medium voltage distribution network of 6-35 kV. One of such factors is the presence of current resonance in the 6-35kV network in the field of generating significant harmonics of the frequency converter. The resonance in the field of significant harmonics arises in networks with long cable lines, where the value of equivalent capacitance is large. Due to changes in the distribution network parameters, the resonance frequency of the currents may change. An urgent task is to develop an adaptive method for ensuring electromagnetic compatibility of frequency converters with a medium voltage network. The adaptive algorithm for pulse-width modulation, which excludes the generation of harmonics in the region of current resonance, can be considered in this way.