Predicting Iron Losses In Magnetic Materials With Non-Sinusoidal Power Supply

According to statistics,60%of the electrical energy is used on the electrical machines in China each year.Therefore,the efficiency optimization of electrical machines plays an important role on energy conservation,which makes reducing motor loss more significant.The core loss accounts for a large proportion in the total loss of the motor,but the accurate calculation for the iron loss of material is still lacks of effective model now,especially under the complex excitation condition of non-sinusoidal in the actual motor.In order to solve this problem,system research was developed from the two aspects of formula calculation and model study,which was based on the physical mechanism of iron loss.The existing Steinmetz formula was tested under practical application,and it was found that there was a big error in the application of this formula under the ferromagnetic material used in the experiment.The analysis pointed out that the parameters of the formula were influenced by the change of the magnetic induction intensity,a new method to modify the parameters of Steinmetz formula was presented in a particular ferromagnetic material;By using the modified parameters,the parameter of MSE calculation formula had been replaced,which improved the accuracy of iron loss calculation under non-sinusoidal excitation by using MSE formula.This paper analyzed of the change of magnetic induction rate influence on the iron loss.Based on the corresponding relationship between the magnetic flux density and the rate of change of the it and the magnetic field strength,the method of calculating the core loss under the given excitation waveform was proposed by using the inteipolation method.Through a series of sine wave experiments,a calculation model was established to calculate the core loss under arbitrary excitation,which could realize the prediction of iron loss in a wide range of continuous magnetic flux change rates.This work improved the non-sinusoidal excitation loss calculation formula and the model analysis method,the effectiveness of the improved method was verified by experiments in the 500WW470 and 500WW800 ferromagnetic materials.