Comprehensive design and analysis of a PMaSynRM for washing machine applications

This study presents a comprehensive design procedure of a permanent magnet assisted synchronous reluctance machine (PMaSynRM) for replacing a permanent magnet synchronous motor (PMSM) in a commercial washer. The motors used in these applications have to perform efficiently on a wide speed range with constant-torque region for washing, and fieldweakening region for spinning. A design methodology is determined consisting of electromagnetic design, thermal/mechanical stress analysis, optimisation and prototyping. There are limitations and decisions on the initial design steps, considering the volume allocated for the machine, magnetic material and permanent magnet (PM) selection and the electromagnetic parameters for constant-torque and field-weakening regions. Design process is carried out following the initial parameter selection then the motor is produced and tested. Test results show that the PMaSynRM is 8.26% higher in volume and lower in power density than those of PMSM with a better field-weakening characteristic and fault tolerance. As a result, the authors proposed a methodology to design a PMaSynRM which becomes a good alternative for the mass produced home appliance motors since the materials' amount are decreased in 20% for silicon steel and 50% for PMs consequently decreasing the total cost and offering nearly the same efficiency and power density for the application.