Design Optimization of Control Moment Gyroscope Spin Motor Under Power-Limited Conditions

The spin motors used in control moment gyroscopes (CMGs) require exceptional precision to meet the stringent demands of spacecraft attitude control. Slotless permanent magnet (PM) machines, which lack the teeth found in traditional machines, naturally offer zero cogging torque, making them ideal for CMG spin motors. This paper introduces a design optimization methodology for slotless PM machines under low-power constraints, suitable for CMG applications. Unlike conventional designs, this approach integrates coil design to accurately reflect the actual fill factor, addressing a common limitation in previous studies that used fixed or approximated fill factors. Additionally, an improved method for calculating AC winding losses, based on precise hot-spot temperature estimation, is proposed. This method ensures accurate loss calculation in the windings, facilitating precise motor power estimation, which is essential for designs under strict power constraints. The optimization is performed using the differential evolution (DE) algorithm to find feasible solutions while adhering to power limitations. The analytical results are validated through finite element analysis (FEA) and experimental results, confirming the accuracy and practicality of the proposed approach for the design of CMG spin motors.