Comparative Analysis of Reliability, Cost and Performance of Three and Five-Phase Synchronous Reluctance Machine Drive Systems with and without Permanent Magnets

This paper compares and evaluates the cost, performance, and reliability of an existing three-phase synchronous reluctance machine (SynRM) drive system when it is revamped by doing at least one of the twofold 1) replacing the three-phase winding by either a star-connected or combined star-pentagon five-phase winding and/or 2) Inserting ferrite permanent magnet (PM) in the rotor barriers. In addition to the existing three-phase SynRM drive, this recycling yields five revamped drive systems. The comprehensive study of the recycling was carried out using Ansys Maxwell Transient Simulation and MATLAB Simulation. The comparison revealed that the star-pentagon five-phase PMa-SynRM drive outperformed the others in terms of performance and reliability. It offers 28.9% higher average torque, 32.75% lower torque ripple, 20.98% higher power factor, 40% less common mode voltage and 1.94% more efficient than three-phase SynRM drive at healthy rated condition. Furthermore, at one-phase fault, it has an 81.5% lower torque ripple and 145% higher average torque than the three-phase SynRM drive, therefore being the most reliable drive system. For the combined cost of machine and converter, star-pentagon five-phase PMa-SynRM drive is only 2.25% more expensive than three-phase SynRM drive. Moreover, this comparison has been experimentally validated.