FQ-14: Volume Optimization of High-speed SPMSM Based on Sequential Quadratic Programming Technique and Analytical Solution

Reducing the motor volume while maintaining optimal performance characteristics enables compact and efficient motor designs. It results in space-saving installations and improved overall system efficiency in various applications, especially air compressors and air blowers [1]. However, achieving such volume reduction without compromising the performance is a challenging task. This paper proposes an innovative approach that integrates the subdomain method [2] with sequential quadratic programming (SQP) to optimize the volume of a high-speed surface-mounted permanent magnet synchronous motor in an air compressor operating at 110000 rpm. Unlike conventional optimization tools that often rely on finite element analysis (FEA) software, by leveraging the subdomain method for electromagnetic modeling, we obtain an analytical solution that accurately represents the behaviors of the motor. Subsequently, the SQP technique is applied to iteratively adjust the geometric parameters and optimize the volume of the model while satisfying design constraints. Fig.1(a) and (b) illustrate the 2D FEA model and the analytical model of the actual motor whose individual parts are shown in Fig. 1(c), (d), (e), (f). Fig.2a and Fig.2b demonstrate a significant reduction of the volume (28.1%) while Fig.2c shows that not only the volume is effectively reduced but also the torque capability is preserved, even having a slight improvement in efficiency in Fig 2d. This is due to the core loss being a majority component in the high-speed motor type which is reduced significantly in the optimized model.References: [1] Z. Huang and J. Fang, "Multiphysics Design and Optimization of High-Speed Permanent-Magnet Electrical Machines for Air Blower Applications," IEEE Trans. Ind. Electron. vol. 63, no. 5, pp. 2766-2774, 2016. [2] K. -H. Shin, H. -I. Park, H. -W. Cho and J. -Y. Choi, "Analytical Calculation and Experimental Verification of Cogging Torque and Optimal Point in Permanent Magnet Synchronous Motors," IEEE Trans. Magn. vol. 53, no. 6, pp. 1-4, 2017.