Research On The Optimization Design Of In-wheel Motor With Ensemble Of Metamodels

With the energy crisis and environment pollution getting worse,the concept of green commuting is widely accepted by people.Electric vehicle is becoming popular among consumers due to its lower energy consumption and less pollution.In-wheel motor driven vehicle which have the characteristics of simple structure and high efficiency have become one of the directions for future development.As one of the core components of the drive system,in-wheel motor is taken into the study subject by researchers.Problem existed in the motor field weakening and overload capacity with controller parameters unchanged should be studied during the electromagnetic optimization design.In this paper,object such as the low-speed high-torque permanent magnet synchronous wheel motor was studied to improve the performance of the wheel motor.Firstly,the match of parameter of the hub motor is carried out by using the principle of the high frequency zone coincide with the high efficiency zone of driving conditions,and rated parameters and peak parameters are determined.Secondly,characteristics such as weakening,over load,loss and partial loading which seems more important to in-wheel motors are analyzed and discussed from the aspects of design parameters of permanent magnet synchronous motor and the control mode in theory.Design parameters of slot parameters,permanent magnet parameters and winding parameters which have influence on the in-wheel motor characteristics are analyzed by using parameter analysis method and relationships is obtained to offer an instruction to electric machine design.Next,the global error and local error accuracy problems which existed in the process of rebuilding the ensemble of metamodels is discussed and several methods to solve the problem of local error and global error is given and results shows that the EG3MM ensemble of metamodels which weight coefficient is obtained by solving the weighted minimum of RRMSE and RMAE can achieve smaller global error and local error in three benchmark problems.Finally,mathematical models among design parameters and the inductance,permanent magnet flux and resistance of the windings is established by using the ensemble of metamodels and the problem of the motor field weakening and overload capacity with controller parameters unchanged are optimized by using ensemble of metamodels and NSGA-II.The optimization results compared with the initial design shows that,considering the optimization of the field weakening and overload capacity,the proposed way has improved the motor with the efficiency range larger than 85%of the motor increased by 11.56%and efficiency in rated point increased with 1.8%,and weight reduced by 12.9%,the overload capacity decreased by 4.7%,but the weakening ratios increased by 19.4%.