Application Of Low Harmonic Winding In High Speed Motor

With the rapid development of motor drive technology,high-speed motors were more and more widely used in industry,at the same time,the requirements for efficiency of high-speed motors under variable frequency supply are also increasing.Harmonics during high-frequency supply and the resulting loss problems became hot issues in the design of high-speed motors.Aiming at this problem,this thesis focuses on the design of low-harmonic windings for reducing the loss of high-speed motors.The main research works are as follows:1)The characteristics of the harmonics caused by the inverter supply and its impact on the internal harmonics of the motor are analyzed;and the characteristics of the internal spatial and time harmonics inside of the motor are also calculated and analyzed;Then,iron losses and copper losses calculation method based on time step finite element(FEM)method are introduced.2)Taking the high-speed induction motor as an example,design idea of low-harmonic winding and the traditional low-harmonic winding design scheme are introduced,and the winding coefficient of low-harmonic winding is calculated;considering that accurate parameters such as winding resistance and leakage resistance are demanded,the length of low harmonic winding and the end leakage calculation formula of stator winding are improved.3)A new low-harmonic winding structure for high-speed induction motors is proposed,and the related winding coefficient of different low-harmonic windings is also calculated and compared.With the time-step FEM,a 37kW high-speed induction motor is taken as an example to compare and analyze the internal electromagnetic harmonics and loss performance of the motor,when the double-stack winding,the traditional low-harmonic winding and the proposed new low-harmonic winding are adopted respectively,and the feasibility and effectiveness of the proposed low-harmonic winding are verified.