Development of Converter Output Voltage Phase-Shift Keying Methods as Applied to a Seven-Phase Motor

Abstract

Phase-shift keying (modulation) of the output voltage of a three-phase converter connected to a symmetrical three-phase winding is one of the stages of the motor vector control technology. This process has well been studied and lies in a practical application field. One of the supposed lines in the development of modern electric traction systems is to construct an electric drive based on a multiphase motor (with the number of phases more than three). In implementing a multiphase motor vector control technology, new opportunities appear, in particular, a new phase-shift keying method. The article considers the voltage phase-shift keying process as applied to a seven-phase winding with the aim to develop seven-phase converter control algorithms implementing the output voltage phase-shift keying, which is possible due to the features of a seven-phase symmetrical motor winding. In the study, the vector analysis techniques and Fourier series expansion methods were used. Experimental studies confirming the obtained theoretical results have been carried out. The scientific novelty of the work lies in that a new converter phase output voltage phase-shift keying method as applied to a seven-phase symmetrical winding and a new converter control algorithm implementing this method have been proposed. The results can be useful in implementing the vector control of a multiphase motor.