| With the development of electronic technology, newly electric and electronic device and high performance permanent magnet material technology, excitation of DC motor was replaced by permanent magnet material, so permanent magnet brushless DC motor appeared. Small in volume, simple in structure, high in efficiency, and little in rotor loss, the DC motor was widely used in medium-small power at present. In this paper, firstly, operation rule of brushless DC motor was analyzed, topological circuit and equivalent circuit equation in six operation intervals under single-flow and inversion mode were discuss in detail. Secondly, by time-step FEM coupling field and circuit,transient electromagnetic field of a 500W eight-poles PM BLDC motor was calculated, simulated and analyzed, and calculation methods of some important parameters also were researched. Simultaneously, the effect of magnetic steel dimension on back electromotive force, flux linkage, and the cogging torque were researched, simulated and analyzed under loads. Thirdly, according to running theory of PM BLDC motor, mathematical model of motor was established and the whole system simulation model based on Matlab/Simulink was developed. Furthermore, the variation of phase current and electromagnetic torque with time under loads respectively were simulated and analyzed. Finally, by comparing the results gotten by Matlab/Simulink with simulation results gained by time-step FEM coupling field and circuit, it suggested that the method adopted and this model developed were correct and some conclusions were gotten, which lay a theoretical foundation for further research of PM BLDC motor.
|
PDF Full Text Request