Detent Force Analysis And Optimization Of Permanent Magnet Linear Synchronous Motor

In the field of linear mechanical industry manufacture, the conventional rotation motor+thread spindle movement mode has been used for long time. Because of its intermediatetransmission device, this movement lead to lower precision, and the movement is not fit fordemand of higher velocity and precision. Permanent magnet linear synchronousmotor(PMLSM) has been researched and developed. However, due to end breaking, endmagnetic field distortion of PMLSM causes end effect force, it results in thrust fluctuationand lower control accuracy.The primary researches of this thesis are calculation and analysis of a12/11PMLSMmachine. First the background, significance and the trending of domestic and internationalof PMLSMs were introduced. The operating principle of the motor, the basic steps of thefinite element method, the basic parameters of the motor were described. On this basis, endforce and cogging force were analyzed and PMLSM air gap field equations were written.The expression of detent force and thrust were described by virtual displacement method.The permanent magnet width, air gap length, end tooth width and height were changed foranalyzing detent force.The results shows that detent force is decreased.Secondly, the model of PMLSM was built to analyze detent force, the PMLSM wasoptimized by combining genetic algorithm(GA) and FEM. Based on the thrustfluctuation and average thrust, the objective function were set up. The optimizationvariables were tooth width, permanent magnet width, end tooth width and height, and thenconstraints were set. Comparing with original motor, the results show that the detent forcewas decreased without deteriorating electromagnetic thrust. Detent force experiment hadbeen conducted and experimental data were obtained. The experimental data werebasically identical to simulation results, but there are errors. At last, conclusions wereobtained.