Investigation of energy-efficiency improvement in an electrical drive system based on multi-winding machines

Abstract

This paper presents an investigation of energy-efficiency improvement of an electrical drive system based on multi-winding machines. An improved power factor (PF) control scheme is proposed allowing energy-efficiency enhancement and optimization in high-power variable-speed drives based on multi-winding machines. Thus, the double-star induction machine is taken, as an example of multi-winding machines, to introduce the principle of the study presented in this paper. In fact, the purpose of this paper is to maintain the PF of the power winding, of the double-star induction machine, in vicinity of unity whatever the drive operating point, allowing discontinuous PWM (DPWM) techniques selection. Therefore, the switching losses can be reduced significantly using DPWM techniques at high PF values and this contributes strongly to energy-efficiency improvement. Moreover, in high-power applications, having low converter losses is essential to maintain thermal limits. In addition, this control scheme can be generalized for several kinds of multiphase machines.