频域寄生电容法变频电机Hertz轴承电流密度计算

提出应用频域寄生电容法计算Hertz轴承电流密度。该种方法以电机系统内的寄生电容为研究对象，通过解析法确定其频域特性，结合电机内耦合电容拓扑结构计算轴承电流。本文以一台3kW变频电机为研究对象，通过解析法确定其各部分寄生电容的频域特性，并通过阻抗分析仪对计算结果进行校验。根据变频器电机系统耦合电容模型列写轴承电流线性微分方程，通过一般线性扩展法对其进行求解，求得轴承放电电流。搭建轴承电流测量平台，对轴承电流进行测量，与计算结果基本吻合。最后应用接触力学中的经典Hertz理论求得轴承接触面积，进而计算轴承电流密度。该种轴承电流密度计算方法为定量评估轴承电损伤提供了理论依据。

Hertz Bearing Current Density Calculation of Variable Frequency Driven Motors by Frequency Domain Parasitic Capacitance Method

This paper applies frequency domain parasitic capacitance method to calculate the Hertz bearing current density of variable frequency driven motor. The parasitic capacitances of the motor system are studied as the research object in this method. A 3kW variable frequency driven motor is studied as the research object in this paper and impedance characteristic of the parasitic capacitance is confirmed by the method of analysis. The impedance characteristic of the parasitic capacitance is also measured to by impedance analyzer check calculation results. According to variable frequency driven motor system coupling capacitance model the bearing current linear differential equation is formulated and solved by the linear expansion general approach. Consequently the electric discharge current is confirmed. The experiment method of measuring the bearing current is improved, and the experimental platform is built. The calculated result of the bearing current is conforming to the measurement value. This kind of bearing current density calculation method provides a theoretical basis for the quantitative evaluation of bearing damage.