A Low-Cost Ferrite Brushless DC Motor for Cordless Power Tool Applications

In recent years, cordless power tools (CPT) have brought numerous innovations enhancing portability, flexibility and efficiency in various industries. A key innovation in this field is the integration of brushless DC (BLDC) motors, although cost reduction remains a priority. One of the major cost factors in cordless BLDC motors is the expense of magnets. Ferrite magnets, with their abundant supply and lower cost, can be used as a viable alternative. This paper proposes a low-cost ferrite brushless DC motor for CPT applications to address this issue. Using a benchmark rare-earth magnet motor, a 10-pole, 12-slot outrunner motor with arced C12 ferrite magnets has been proposed. The stator and rotor design parameters of the proposed design have been optimized using trial-and-error method and design considerations. Key elements involved in the mechanical assembly of the proposed design are detailed in the paper. Furthermore, the proposed ferrite motor’s electromagnetic performance has been simulated and compared to the benchmark. The structural and computational fluid dynamics (CFD) analysis of the proposed design have been provided. Finally, a functional prototype of the ferrite magnet motor has been built and its experimental results have been validated against simulation data.