自由活塞内燃机用直线发电机的设计与分析

Design and Analysis of Linear Generator Used for Free Piston Internal Combustion Engine

自由活塞内燃发电机是一种新型动力装置,该装置中直线发电机的动子运动规律受缸内燃烧状况的影响,动子不同运动规律及永磁体充磁方式均会影响直线发电机的性能。运用有限元法分析动子不同运动规律及永磁体不同充磁方式下直线发电机的空载及负载特性。分析结果表明,匀速运动下感应电动势正弦波形畸变率最小。相同极弧系数下,径向充磁方式下空载定位力幅度比轴向充磁更大、空载反电动势正弦波形畸变率更小。相同负载下,径向充磁方式下的输出功率及动子所受的电磁力均比轴向充磁大。

The free piston internal combustion generator is a new type of power plant.The motion of the moving part in the linear generator is affected by the combustion status inside the cylinder.Different motion laws of the moving part and the magnetization mode of permanent magnet will affect the performance of linear generator.The finite element method was used to analyze the unloaded and loaded characteristics of the linear generator with different motion laws of the moving part.The effect of different magnetization modes of permanent magnet on the performance of linear generator was also investigated.The simulation results show that the sine wave distortion rate of the induced electromotive force is the smallest if the linear generator moves with constant velocity.With the same polar arc coefficient,the amplitude of the unloaded detent force under the radial magnetization is greater than that of the axial magnetization,and the sine wave distortion rate of the unloaded back EMF is smaller.With the same load,the output power and the electromagnetic force under the radial magnetization are larger than the axial magnetization.