Influence of Variable Air Gap on the Electromagnetic Performances of Permanent Magnet Brushless DC Motor

抄録

Simulation models of permanent magnet brushless DC motor with cam rotors and two kinds of uniform air gap motor determined by two limit arcs of the cam rotor were established on the basis of JMAG software. These simulation models were used to determine the influence of regularly varying air gap, which is formed during the rotation of the two cam rotors of the hydraulic motor pumps integrated with a cam rotor vane pump and a permanent magnet brushless DC motor, on the electromagnetic performance of the motor. The electromagnetic performance of the three kinds of motors were simulated and compared under rated and variable loads, respectively. Finally, the cam rotor motor prototype was developed for experimental research. Results show that the starting time of cam rotor motor under rated load is 20% shorter, and its output torque ripple is 23% smaller than those of the uniform air gap motor determined by the minimum limit arc of the cam rotor. However, the air gap flux density curve of the cam rotor motor weakens obviously amongst the three motors. Under different loads, the efficiency of the cam rotor motor is the highest amongst the three motors, and its mechanical property is hard. The research results can lay a theoretical foundation for the development of cam rotor motor pumps.