Design Optimization for Micro Permanent Magnet Brushless DC Motors

Abstract

Products that use micro permanent magnet brushless DC (PM BLDC) motors have the advantages of being small in size, lightweight, highly efficient, and more reliable. The product trend within the electronic technology moves toward the direction of miniaturization and high quality and thus the PM BLDC motor industry has a great potential for developments. Based on a case study on the micro PM BLDC motors for driving cooling fans, this study is to investigate the way of applying a systematic design for analyzing design parameters of brushless DC motors. The objective of this study is to reduce development costs and enhance the quality of motor operations. For a conventional motor design, designers use analytical methods to analyze and calculate the design parameters and performance parameters so that they can build a mathematical model for permanent magnets. However, in reality based on the consideration of product development parameterization and design optimization, conventional methods of analyzing magnetic circuits might fail to effectively meet the project deadlines and performance requirements within this industry. Moreover, for the application of micro PM DC motors to product designs, a motor is required to meet different requirements for its design specifications depending on the characteristics of different functions or implementations. Its design parameters need to change accordingly. Therefore, by integrating an approach of magnetic circuit analysis, a process of designing motor products was firstly determined by using the FORTRAN programming language in this study so that the specifications can be stipulated for a preliminary design. After that, the operation performance was determined by calculations and a model for finite element analyses was created based on the results. The JMAG software was also used for the analysis of motor designs. This approach can enhance the efficiency of micro motor designs and analyses so as to reduce the time spent on remodeling and numerical analysis. A fast parametric design method is proposed in this study and its effects and results were further verified.