Design optimization of a small single-phase motor with auxiliary permanent magnet

In the paper, a design procedure is developed to optimize the performance of a single-phase permanent magnet motor (SPPMM) for pump application by integrating an auxiliary permanent magnet (APM) on the stator side. First, a mathematical model to simulate the dynamics of the existing motor without APM is implemented, including both a nonlinear electromagnetic and the mechanical characteristics. Then, the contribution of the APM torque is taken into account, showing the achievable benefits on the dynamic performances with respect to the actual SPPMM. Finally, optimal design scenarios are analyzed involving both the motor and the auxiliary part parameters. The results evidence the remarkable enhancement at the starting condition, the reduction of the torque and speed ripple as well as of the ohmic losses at steady-state.