Analysis of temperature field for a surface-mounted and interior permanent magnet synchronous motor adopting magnetic-thermal coupling method

Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.

Influence of Magnet Shape on the Cogging Torque of a Surface-mounted Permanent Magnet Motor

The influence of bread-loaf shaped magnet poles under parallel magnetization on the cogging torque of surface-mounted permanent magnet(SPM)motors is studied.For the SPM motors having magnetic poles with eccentricity and sine harmonic compensation,the electromagnetic performances of integer and fractional slot motors are compared.It is found that the cogging torque and torque ripple of the integer and fractional slot motors can be reduced with the same eccentric magnet pole.The cogging torque and torque ripple of a fractional slot motor can be decreased by sine harmonic compensation,however,the same sine harmonic compensation has a small influence in integer slot motors.By varying the magnetic poles,the contribution of the field harmonics(k=(2n+1)p),which are a direct result of magnet magnetization,to the cogging torque also changes.The electromagnetic performance of a 3 kW prototype is tested,and it is found that the experimental results validate the theoretical investigation.

Multi-Objective Optimization of Surface-Mounted and Interior Permanent Magnet Synchronous Motor Based on Taguchi Method and Response Surface Method

The surface-mounted and interior permanent magnet synchronous motor(SIPMSM)has the characteristics of multiple variables,strong coupling and nonlinearity.In order to improve the performance of SIPMSM,this paper presents a multi-objective optimal design process using Taguchi and response surface methodology(RSM).The peak value of cogging torque(PVCT),ratio value of average torque and permanent magnet weight(RTW),torque ripple and back-EMF total harmonics distortion(ETHD)are selected as optimization goals.The experiment matrix is established by Taguchi method,and analyzed the tendency and proportion of the effect of the optimization parameters on SIPMSM performance.The rules of choosing multi-objective optimization parameters are obtained.The least-squares method is used to establish the optimal objective function,and RSM is used to obtain the resolutions of the optimization objective function.Comparing the initial performance with optimized performance verifies the effectiveness of the proposed method.

Study on the Peripheral Magnetic Leakage and Shielding Measures of Surface-mounted Permanent Magnet Motor

Permanent magnet(PM)motors are widely used in our daily lives.Taking a surface-mounted PM motor as an example,a magnetic circuit model considering the peripheral magnetic flux leakage is established.Maxwell software is used to simulate different loads and thicknesses and the materials of the shielding layers.The magnetic flux leakage around the motor has a sinusoidal distribution in the space.The value of the magnetic flux leakage is inversely proportional to the power of P+1 from the surface of the core.The thicker the shielding layer,the smaller the magnetic leakage.The greater the relative permeability of the shielding layer,the better the shielding effect.The results provide ideas and recommendations for the magnetic flux leakage analysis and the design of non-magnetic or low magnetic motors.

A Sensor-less Surface Mounted PMSM for Electronic Speed Control in Multilevel Inverter

Recent advancements in power electronics technology evolves inverter fed electric motors.Speed signals and rotor position are essential for controlling an electric motor accurately.In this paper,the sensorless speed control of surface-mounted permanent magnet synchronous motor(SPMSM)has been attempted.SPMSM wants a digital inverter for its precise working.Hence,this study incor-poratesfifteen level inverter to the SPMSM.A sliding mode observer(SMO)based sensorless speed control scheme is projected to determine rotor spot and speed of the multilevel inverter(MLI)fed SPMSM.MLI has been operated using a multi carrier pulse width modulation(MCPWM)strategy for generation offif-teen level voltages.The simulation works are executed with MATLAB/SIMU-LINK software.The steadiness and the heftiness of the projected model have been investigated under no loaded and loaded situations of SPMSM.Furthermore,the projected method can be adapted for electric vehicles.

表贴式永磁电机电枢磁场合成

为减小表贴式永磁电机磁场解析中矩阵的维度,提出了基于单槽模型的电枢磁场合成方法。假设电机仅单槽通单位电流激励,将完整电机分析域简化为单槽模型,结合单槽模型的边界条件、磁场对称性,采用子域法获得单槽电机的磁场分布。针对单层和双层分布绕组结构电机,在不同槽电流激励时,通过单槽模型磁场的移相、叠加,获得总的电枢磁场;针对双层集中绕组结构,将单槽电机的激励分解为两个相同的独立激励,构造对称磁场,合成出电枢磁场。所提方法无需对电机所有定子槽建模,降低系数矩阵的维度。通过有限元仿真和实验验证了电枢磁场合成的准确性。