Design And Optimization Of 75KW Switched Reluctance Motor For Air Compressor

In the field of air compressor,high energy efficiency,compact structure and low vibration noise have already been its development trend in China.The main motor is a key component of air compressor and the type of it plays an important role in the energy efficiency of air compressor.Notably,the switched reluctance motor(SRM)is a significantly competitive adjustable speed motor for its high efficiency,good speed regulation performance and simple structure.However,the design of its inherently double salient structure leads to large vibration and high noise during the operation of SRM.Therefore,from the aspects of motor design and structure optimization,this thesis proposes an optimization method of the motor structure to achieve the goal of reducing torque ripple of SRM.First of all,the development of main engine of air compressor and driving motor was introduced in general.The typical characteristics of main engine of single-screw air compressor and SR motor were analyzed.And the basic theories of single-screw air compressor and SR motor were illustrated in detail.On this basis,according to the property requirements of the driving motor for single-screw air compressor and the design concept of the SR motor,a 75 kW three-phase 12/8 pole SR motor was designed by Mathcad.The electromagnetic characteristics of the motor were analyzed by Ansoft software to check the rationality of the motor design.Secondly,it is well known that the radial magnetic force is the main source of vibration and noise of SR motor and thus in this thesis,analysis of the radial magnetic force were carried out.It is found that stator polar arc coefficient,rotor polar arc coefficient,air gap length,stator yoke thickness,rotor diameter and other parameters have influence on the magnitude of radial magnetic force.In addition,the extracted structural parameters were analyzed by single parameterization.In order to improve the optimization efficiency of the motor,this thesis adopted the response surface analysis method,constructed the sample space through Box-Behnken(BBD)sampling principle,and established the SR motor response surface model,which provided an excellent nonlinear mathematical model for the following multi-objective optimization.Considering the coupling relationship of multiple parameters of SR motor,the improved bare-bones particle swarm algorithm was used to optimize multiple parameters of the motor.After crossover evolution to convergence,the combination of structural parameters satisfying the minimum objective function was determined to reducethe radial force amplitude and increase the average torque.The feasibility and reliability of the optimization method were confirmed by comparing the as-received motor performance and optimized motor performance.The research results of this thesis are of great significance to the optimal design of SR motor.