Performance calculation of brushless DC motor

In this paper the performances of a tangentially magnetized brushless DC motor are calculated and tested. For the calculation, both circuit method and finite-element method (FEM) provided by commercial software Ansoft are used. With the circuit method, motor design and performance calculation can be performed. A prototype motor is designed and calculated, and the curves of voltage, current, torque and efficiency are given. The measured results are also given in the paper, and the calculated and measured results are in good agreement. With the FEM, both no-load and loaded performances of the prototype motor are calculated in detail. The curves of no-load back electromotive force (BEMF), loaded torque, and loaded BEMF are given. The measured BEMF curve is also given, the calculated and measured BEMF curves are in good agreement. Since the results obtained from the circuit method and FEM are both consistent with the experimental results very well, reliable foundation has been established for further design and optimization.