Research On Efficiency And Noise Of Permanent Magnet Motor Used In Compressor

As the core power part of air conditioning compressor, the efficiency and noise paoblems of permanet magnet motor directiy affect the overall performance of compressor. Efficiency and noise of permanent magnet motor tend to be relate to each other, even contradictory. Analysis of the efficiency and noise performance of permanent magnet motor will have practical significance. In combination with the application background of the compressor motor, this ariticle will research and analysis revolved around efficiency and noise of permanent magnet motor problems.Firstly, the paper discusses the calculation method of core loss and influence factor. To accurately calculate the core loss, considering the rotation of magnetization and harmonic magnetic field, in this paper, based on the orthogonal decomposition of iron loss model, we amend the loss coefficient by considering the influence of flux density amplitude on the core loss coefficient. Variable coefficient orthogonal iron loss model is given out and the model accuracy is verified from the no-load iron loss test, which mechanical loss obtained by no magnetic rotor. Based on the iron loss model, we reseach the influnence of the main air ga p magnetic field for core loss. In this paper, on the premise of considering actual industrial production, an optimization measure of rotor is put forward, which the rotor is composed of three different radius of circular arc. As the coefficient of motor torque constant, this form can adjust motor air gap magnetic field waveform and decrease the motor iron core loss and improve the efficiency of the motor.Secondly, The radial electromagnetic force is the main cause of motor vibration and noise, from the air gap magnetic field the radial electromagnetic force of permanent magnet motor is deduced and verified by finite element method. For the convenience of analysis and highlight the main problem, we ignore the high harmonic magnetic field genrated by high harmonic magnetmotive and the tooth harmonic permeance. The primary order force and frequency characteristic of load and no-load are analyzed respectively.Thirdly, under the background of the compressor application, the paper studies the stator modal of permanent magnet synchronous motor. On the premise of the same refrigerant flow area, the influnence of stator yoke cut shape for core modal frequency is compared. This paper design the stator yoke combined cut with groove, which have the highest of the stator stiffness, to some extent, it can reduce the noise. Through the dynamics analysis, the electromagnetic vibration can be calculated and the electromagnetic noise can be calculated by the acoustic radiation model. The influence of air gap magnetic field waveform of motor noise is compared, the result show that the proposed optimization measure of rotor can reduce the motor noise.Finally, electromagnetic load ratio directly decided the motor copper loss and iron loss distribution, which determine the motor efficiency. And the magnetic load directly effect on the radial electromagnetic force, which affect the electromagnetic noise, so the motor efficiency and noise performance constraints to each other. The paper annlysis the influence of electromagnetic loaddistribution and the propoetion of teeth and yoke for loss distribution and electromagnetic noise. Balancing the efficiency and noise of the permanent magnet synchronous motor under two load condition, the best electromagnetic load ratioand the propoetion of teeth and yoke are determined. After motor structure parameters were confirmed, the motor is designed and processed. The no-load and load experiment is done and the results agree with the simulation.