A NEW MULTI-STACK POLYPHASE SYNCHRONOUS RELUCTANCE MACHINE

Abstract

A hybrid polyphase synchronous reluctance machine comprising a cylindrical rotor and a salient pole rotor mechanically coupled together and integrally wound has been reported recently as a high torque device. This paper describes how the hybrid machine can be simulated with only salient pole machines and investigates some performance indices of the machine. The proposed machine comprises three mechanically coupled salient pole machines designated as stacks A, B, C. Each stack machine has two sets of magnetically coupled identical windings star-connected on the stator side, known as the main and control windings respectively. The main windings of each stack are interconnected in series and connected to the utility supply while the control windings are integrally connected and feeds a variable capacitance load. A unique feature of the machine is that although the d-axis to q-axis reactance ratio of the machine is fixed by the geometrical configuration of the rotors, its operational value is dependent on the capacitance loading of the control winding. By the judicious choice of capacitance loading of the control winding, this ratio ranging from 0 to ±∞ is obtainable, which in turn indicates a great improvement on the output power and power factor of the conventional synchronous reluctance machines.