Reliability-Based Design Optimization of a Permanent Magnet Motor under Manufacturing Tolerance and Temperature Fluctuation

A reliability-based design optimization (RBDO) method is proposed to ensure a given confidence level of output performances of a permanent magnet motor in the presence of operating temperature fluctuation and manufacturing tolerance. To achieve the goal, first, probabilistic distributions of material properties of motor components are investigated in accordance with the variation in operational temperature. Then, random material parameters and random design variables due to both uncertainties are incorporated into a mathematical formulation of the RBDO, and an optimal design is sought out using the Monte Carlo simulation combined with a highly accurate surrogate model. An interior-type permanent magnet synchronous motor is provided to demonstrate the validity of the proposed method by comparison with the conventional method, which adopts a deterministic optimization technique in conjunction with a safety factor.