Design And Optimization Of A Low-speed Direct-drive Switched Reluctance Motor For Industrial Valve Applications

Electric actuators for valves are widely used in modern industrial drive system.They mostly use induction motors as main components,supplemented by reducers,controllers,transmission gears and other components.Due to the harsh working environment and complicated working conditions of industrial electric valves actuators,the reduction gear is the most vulnerable part.Therefore,the electrical actuator conducted by direct-drive system without gear system has attracted much attention due to its advantages of quick response and high reliability.Based considering the rated speed and manufacture cost,switched reluctance motors are more commonly used in direct-drive electrical actuators.In this dissertation,the performance and parameters of ABB’s MOE712 electric actuator are used as design indicators to carry out the design and research of switched reluctance motors for electrical actuators.By implementing the high pole slot number and S2 working system(short-time working system)the initial design of the switched reluctance motor has been completed.After that,its electromagnetic characteristics and thermal characteristics are simulated as well.The thesis mainly includes following contents:(1)The influences of motor’s main structural variable on the output performance are obtained by theoretical analysis.And the initial model of the motor is designed;ANSOFT is used to simulate and analyze the electromagnetic characteristics and output performance of the motor,Which provides a base line for optimization.(2)In order to reduce the computation time of optimization,surrogate is used to optimize the initial motor.According to sensitivity analysis,the optimization constraints are that slot full factor is between 50%-60% and the torque ripple should be less than 30%,and average torque should be greater than 150N·m.Optimization variables are stator yoke thickness,rotor yoke thickness,stator pole brace,rotor pole brace,rotor slot depth,number of turns,winding diameter.(3)Latin hypercube sampling is applied to obtain the sample points of the optimized variables,and ANSOFT is used to simulate the output characteristics at different sample points;the Kriging method is implemented to construct the initial surrogate model with optimization objective function of the motor output characteristics and optimized variables;particle swarm optimization is used to find the optimal solution of motor’s efficiency.(4)Use ANSYS to simulate optimized motor’s temperature characteristics,and verify feasibility of the optimized motor.By adopting surrogate model,the computation complexity of motor optimization is reduced,and optimization time is reduced from 87 h to 10 h,the torque ripple of the motor is reduced from 36.5384% to 29.0559%,the efficiency is increased from 52.45% to 54.15%,and the torque is 156.4994N·m which meets the design requirements of electric actuators for industrial valves.