永磁直流电动机气隙磁密波形的确定

Determination for Magnetic Density Wave in the Gap of the Permanent Magnet DC Motor

永磁直流电动机的气隙磁密波形直接影响每极磁通量，影响电机的工作特性、振动和噪音．文中分析了平顶波磁密对电机铁耗、空载阻转矩的影响，比较了平顶波和近似正弦波磁密电机对应的工作特性，三种特性曲线分别都有明确交点的事实决定了这两种磁密波形对电机性能的适应性：轻载长期运行电机宜选用正弦波磁密，而重载或频繁起动等短时或重复短时工作电机宜选用平顶波磁密，用于轻载、要求高效、空载电流、振动、噪音要求小的场合，应选用近似正弦波磁密．文中还就获得这两种不同波形的充磁方法提出改进意见，并推出两种新的磁钢结构型式：“不等原瓦形磁钢”可获正弦波形磁密，磁钢充分利用，磁密波形稳定；“等厚瓦形人字斜磁钢”可获平顶波磁密，电机空载电流、振动噪音等性能可得到明显改善．

This paper describes the influence of magnetic density wave in the gap of the permanent magnet DC motor upon the motor working characteristic,and compares three working characteristics which are corresponding to the magnetic density waves of flat-roofed and near-sinusoid.The fact that the working characteristics corresponding to the two waves definitely intersect determines the adaptability of magnetic density wave to the motor working characteristic.It is suitable that the magnetic density wave of sinusoid should be adopted the light-load,long-running motor,and flat-roofed one should be adopted the high load or frequent-startup motor.In this paper,the author presented two new magnetic pole structures of pemanent-magnet DC motor to attain the optimal motor performance.