A general approach to sizing and power density equations for comparison of electrical machines

TLDR

Designing electrical machines for power converters requires system‑level optimization rather than simple sizing, and comparing the many available machine types can be challenging. The study proposes a general sizing equation that can be adjusted for any machine topology and waveform. The authors develop a method to formulate this equation, taking into account machine characteristics and input waveforms. Applying the equations, the authors compare induction and doubly salient permanent magnet machines, demonstrating the approach’s usefulness.

Abstract

Whenever an electrical machine is meant to be fed by a power converter, the design should be approached as a system optimization, more than a simple machine sizing. A great variety of electrical machines is available to accomplish this goal, and the task of comparing the different options can be very difficult. A general purpose sizing equation, easily adjustable for every topology, that could take into account different waveforms and machine characteristics, would be a very desirable tool. In this paper, a general approach is presented to develop and to discuss such an equation. Sample applications of the sizing and power density equations are utilized to compare the induction machine and the doubly salient permanent magnet (DSPM) machine.