Multiobjective Design and Performance Analysis of the Ultra-Low Speed Axial Flux Disc Motor for Maglev Wind Yaw System

A novel maglev wind yaw system (MWYS) based on the maglev technique and direct-drive structure was proposed to reduce the yaw power and failure rate. We first introduced the attraction force fluctuation and dynamic response time into the optimized design of axial flux motor, and constraints considering suspension startup, dc input voltage of suspension converter, and safe pitch limitation are given. Using multiobjective sequential quadratic programming technique, an optimization process is performed for minimizing the suspension losses, attraction force fluctuation, and the fastest attraction force dynamic response, considering the practical constraints. Ultra-low speed requirement makes the yaw motion easily vibrate with torque pulsation; we adopt the stator fractional slot structure and build stator slot permeance function and some constraints to perform the optimization of the stator construct parameters for minimizing cogging torque by the Lagrange function method. Finally, the design example is given and a prototype is manufactured. The experimental results show that the presented design method, structure, and the MWYS are feasible.