Study on eddy current loss for active magnetic thrust bearings considering load variation, noise, and switching ripple currents

Calculation of eddy current loss is an essential job in magnetic thrust bearings(MTBs) design in specific applications. In this work, a comprehensive model of eddy current loss in MTBs is presented. In this model, a fractional-order dynamic model is applied. The model parameters are estimated by heuristic optimization algorithm. The close loop model is constructed with the dynamic current stiffness and displacement stiffness. In this model, the load variation and sensor noise are considered. The eddy current loss brought by load variation and sensor noise is analyzed then. A pulse width modulation(PWM) switching power amplifiers(SPA) is also modeled and the switching ripple current(SRC) is calculated by finite element analysis(FEA). This result is applied to calculate the loss brought by SRC. According to the simulation results, it is concluded that the heat by SRC is dominant in common applications.