基于端部漏磁场分析的集成式电机驱动系统在线匝间短路故障诊断

On-line Inter-turn Short Circuit Fault Diagnosis of Integrated Motor Drive System Based on Analysis of End-leakage-flux

基于宽禁带器件的变频器具有高功率密度和耐高温工作的优势,通过小型化和轻薄化设计可以将变频器置于电机端盖与端绕组之间,构成结构紧凑的集成式电机驱动系统。该系统发生匝间短路故障时,短路绕组电流增大不仅会使电机内部温度升高导致电机绝缘性能降低,还将引起磁场变化影响变频器的正常工作。以一台1.5 kW的交流感应电机为例,搭建基于宽禁带器件的集成式电机驱动系统三维物理模型,利用数学解析法分析并计算匝间短路故障前后的端部漏磁场,并提取电机内端部印制电路板(printed circuit board,PCB)表面与轴心距离相等、机械角度相差45°的两点处磁感应强度在直角坐标系下椭圆曲线的离心率反映端部漏磁场的对称性,以此为特征指标判断电机是否出现匝间短路故障。仿真与实验结果验证了所提方法的正确性和有效性。

The inverter based on wide bandage devices has the advantage of high power density and high operating temperature,which can be placed between the motor end cap and end winding by miniaturization and slim design to form an integrated motor drive system with compact structure.When an inter-turn short circuit fault occurs in the integrated motor drive system,the increase in short circuit winding current not only causes the increase of the motor temperature that leads to a reduction of insulation,but also leads to changes in the magnetic field which further affects the operation of the inverter.A 1.5 kW AC induction motor was used as an example to build a three-dimensional physical model of an integrated motor drive system based on wide-bandage devices,and the end-leakageflux before and after an inter-turn short circuit fault was analyzed and calculated by mathematical analysis,and then extracted the magnetic flux density ellipse eccentricity in the x-y coordinate system of two points on the surface of the PCB at the equal distance from the center of the axis and at the difference of the mechanical angle of 45°to reflect the symmetry of the end-leakage-flux field,which was used as characteristic indicator to diagnose whether the motor has an inter-turn short circuit fault.The simulation and experiment results verified the correctness and effectiveness of the proposed technique.