Design and optimization, steady-state and dynamic analysis of synchronous reluctance motors controlled by voltage-fed converters with nonlinear controllers

Abstract

This paper presents innovative results to improve the design and manufacture of high-performance synchronous reluctance machines. These results have been obtained from our research in analyzing and synthesizing advanced control algorithms to promote the competitiveness of three-phase synchronous reluctance machines in electric drives in comparison with permanent-magnet synchronous motors and induction machines. These results have direct application in the design and manufacture of electric- and hybrid-electric drivetrains for light-, medium-, and heavy-duty vehicles. First, we report on the dynamic optimization of medium duty synchronous reluctance machines described by nonlinear differential equations. Second, we describe a new design optimization method, based upon nonlinear electromagnetic analysis, to improve steady-state performance and to enhance the operating envelope. Highly efficient, high-speed synchronous reluctance motors, ranging from 10 kW to 100 kW, were manufactured and tested. The design methods ensure cost-effective production of a new generation of state-of-the-art synchronous reluctance motors. This paper develops a nonlinear model of synchronous reluctance motors that incorporates saturation effects. Kirchhoff's and Newton's laws are used to derive the models. The application of Park's transformation results in a set of differential equations in the rotor reference frame; the q-, d- and zero-axis voltage and current quantities are used in analysis, modeling and design. Robust controllers are developed to guarantee closed-loop system stability and attain the disturbance rejection.