Calculation And Analysis Of The Power Loss In The HTR-PM Helium Circulator Active Magnetic Bearing

The active magnetic bearing (AMB) with the advantage of no friction, nomechanical wear, active control, now has become an ideal choose for the rotorsupporting system in the nuclear power plant. However there is no precedent for theactive magnetic bearing applied in the nuclear power plant (HTR-PM). The power lossin the active magnetic bearing is a very important and complex problem, and so it hasan important theoretical and practical value.There is no mechanical friction in the magnetic bearing, but copper loss, iron lossand windage loss are present in the active magnetic bearing. The power loss in the AMBmay cause the malfunction of the high-temperature. With the background of theNational Major Projects, the application of the helium circulator of the HTR-PM, thispaper analyzes the power loss of the AMB.Firstly, this paper analyzes the iron loss of the AMB under the alternating magneticflux. Researching the mechanism of the hysteresis loss and the eddy current loss in themagnetic materials, the paper analyzes the law of iron loss in the AMB. Based on theexperiment data of the35H300silicon steel lamination, this paper examine theapplicability of the iron loss separation law under the circumstances of high frequencyand high density magnetic flux by data fitting. Meanwhile, calculate the iron loss of theAMB under the alternating magnetic flux by FEM method and analyze the AMB’spower loss regulation under the condition of the alternating magnetic flux. Under thealternating magnetic flux condition the hysteresis loss of active magnetic bearing islinearly related with the current frequency. The eddy current loss has a linearrelationship with the square of current frequency. And the hysteresis loss occupies themajority of iron loss when the current frequency is low, however when the currentfrequency is high, the influence of eddy current loss will become obvious.Then, the paper also studies the AMB’s power loss under the condition of therotational magnetic flux. Meanwhile, the way of the magnetization of the magneticmaterial, and the calculation of the iron loss, are also stated. Besides, the HTR-PMAMB’s copper loss, iron loss and windage loss are calculated. In addition, the AMB’sinternal electromagnetic field and power loss are calculated using both mathematicmethod and FEM method. Then the result of those two results are compared and the effective volume parameter of the empirical formulation are modified. The researchesindicate that under the rotational magnetic flux, the power loss of magnetic bearing ismainly due to the eddy current loss. Besides, under the condition of rated speed, therealso exists copper loss, hysteresis loss and windage loss in HTR-PM helium circulator,which should not be ignored. The results of this paper lay the foundation of theindustrial application of the HTR-PM helium circulator.