Research On Similarity Of Brushless DC Linear Motor

The research on similarity of a series of motors which have a similar structure and different sizes is to seek for the intrinsic relationship and laws from their structure and characteristic. The application of these laws has great referenced worthiness for motor design, such as shortening period of design, reducing cost of examination. Based on the combination approach of analysis method and finite element simulation, This paper has researched the similarity of structure and thrust characteristic of Brushless D.C. Linear Motor (BLDCLM).Firstly, the cogging force similarity of BLDCLM is analyzed by the way of analysis method. And based on expounding variety approaches for slot effect, this paper uses area function and monopole function to set up model for slot effect from the thrust fluctuation perspective, and then the cogging force ratio expression of two motors which have similar structure and different sizes is educed based on the detailed analysis of this model. What is more, this expression provides theoretical bases for analyzing Permanent Magnetic Linear Motor similarity.Secondly, this paper builds two finite element simulation models of BLDCLM, and then alveolus ratio, slot coefficient and pole embrace coefficient which are three influencing cogging force factors are respectively simulated by Ansoft software. Based on the simulation result, the similarity law of respective factor which has influenced cogging force and thrust characteristic is analyzed. Pole embrace coefficient which influences cogging force is analyzed by Fourier Series. The method of impairing cogging force, from the aspect of choosing proper pole embrace coefficient, is educed by analyzing effect of pole embrace coefficient to fourier decomposition coefficient.Finally, the combination of field with circuit is feasible to analyze the structure similarity of BLDCLM. The ratio expression of yoke thickness to polar distance is educed, and this ratio range is also gained by finite element simulation, which provides referenced bases for analyzing the structure similarity of Permanent Magnet Linear Motor. The performance parameters of motors of different types and different volumes get a fluctuation within a certain range on...