Performance Comparison of Synchronous Reluctance Motor and Interior Permanent Magnet Synchronous Motor for Traction Application

Abstract

Traction motor forms an indispensable part of electric vehicle system. Making its right choice will ascertain the range anxiety, maximum speed and battery ratings required for the electric vehicle. The radical increase in the cost of rare earth magnet materials has pressurized all the countries to come up with rare earth magnet free motor as the traction choice. Interior permanent magnet synchronous motor (IPMSM) is the most widely used one although it suffers from the risk of demagnetization at higher temperatures. Due to the aforesaid reasons its popularity is diminishing. This scenario clearly indicates the requirement of feasibility check for Synchronous reluctance motor (SynRM) as the traction choice. This paper provides an in-depth discussion about the performance analysis of SynRM under the following heads: Peak torque capability, continuous thermal envelope, inverter rating and drive cycle analysis. Here the efficiency maps across the entire speed and torque range is studied with Worldwide Harmonized Light Vehicles Test Procedure (WLTP) Class 2 drive cycle. Thereafter these performance indies are compared with an IPMSM of comparable power rating. Another important aspect highlighted here is the tradeoff study between cost, weight and efficiency of the designed motor that will bring in a holistic picture.