Calculation And Analyzing Of Iron Loss Of Induction Motor Under Non-sinusoidal Excitation

Induction motor(IM)'s iron loss will change greatly under non-sinusoidal excitation comparing to under sinusoidal excitation. IM's iron loss will increase in a certain degree which dependents on the characteristic of excitation source. The actuate calculation of IM's iron loss is important to high performance control or optimal design of IM. Designing of the more actuate calculation of IM's iron loss method is a valuable problem.Based on the analysis of characteristic of iron loss of IM fed by non-sinusoidal excitation, a more actuate iron loss resistance model of IM fed by non-sinusoidal excitation is build and the calculate method of iron loss during magnetic design of IM fed by non-sinusoidal excitation is improved in this thesis.Iron loss calculation model of IM under sinusoidal excitation is analyzed. According to the difference of cause, iron loss of IM can be classified to three component: the hysteresis loss, the classical and excess loss. The three components varies in a different manner with magnetic density and switching frequency of iron core. Then the different calculate methods of iron loss of IM under non-sinusoidal excitation are compared and validation methods of the calculate result are presented. The method based on the iron loss separation model calculate iron loss by analyzing iron loss variation of iron loss under non-sinusoidal. The harmonic analyzing method divides the non-sinusoidal waveform to several sinusoidal waveforms and then using the sinusoidal calculation model calculating their iron loss, the total loss is the addition of these iron loss components. Then a more actuate iron loss resistance model of IM fed by non-sinusoidal excitation is build. To considering the different variation of each iron loss component with magnetic density and frequency, each iron loss component is represented by a single resistance in the model which will improve the precision of calculate result. The expression of these resistance is induced and the method that determine the model parameters is designed. Correctness and validity of the proposed model is verified by the simulation and the experiment results. Then the calculate method of iron loss during magnetic design of IM fed by non-sinusoidal excitation is improved. The calculation of harmonic magnetic density of IM fed by non-sinusoidal is analyzed and the calculate result of magnetic density is amended to considering the influence of harmonic magnetic density to the iron loss. The simulation result show that the calculating precision of iron loss of IM is improved.