Afternoon tea also known as low tea,is a light meal typically eaten between 3pm and 5pm.The custom of drinking tea originated in England when Catherine of Braganca married CharlesⅡin 1661 and brought the practice of ...Afternoon tea also known as low tea,is a light meal typically eaten between 3pm and 5pm.The custom of drinking tea originated in England when Catherine of Braganca married CharlesⅡin 1661 and brought the practice of drinking tea in the展开更多
The permanent-magnet(PM) spherical motor has special configuration and complicated distribution of electromagnetic field.The spatial distribution of the effective flux density produced by permanent magnets is obtained...The permanent-magnet(PM) spherical motor has special configuration and complicated distribution of electromagnetic field.The spatial distribution of the effective flux density produced by permanent magnets is obtained,and the end-effect of the permanent magnets is analyzed.In the 3-dimensional(3-D) finite element(FE) analysis,the calculation of Back-EMF charac-teristics of the PM spherical motor needs to be conducted by steps,which leads to large computational burden.A novel ana-lyzing method to quantize the end-effect of the PM spherical motor is proposed,that is,the end-effect coefficient of the PM spherical motor is calculated to revise the back-EMF waveform obtained from the 2-D FE model.Under different outer radii of the stator coil and different pole arc coefficients of the PM spherical motor,the revised 2-D results are validated by the results obtained from the 3-D FE model and the experimental results.With this method,the special structural feature of the PM spherical motor is fully considered;the pure 3-D calculation of electromagnetic field is conducted only once;higher precision and less computational burden can be achieved.The method provides a new approach to investigating the back-EMF charac-teristic of the PM spherical motor.展开更多
文摘Afternoon tea also known as low tea,is a light meal typically eaten between 3pm and 5pm.The custom of drinking tea originated in England when Catherine of Braganca married CharlesⅡin 1661 and brought the practice of drinking tea in the
基金supported by the National Scientific Fund for Distinguished Young Scholars (Grant NO.50825701) the Key Program of National Natural Science Foundation of China (Grant NO.51037004)+1 种基金the National Natural Science Foundation of China (Grant NO.51077097)the Key Technologies Research and Development Program of Tianjin (Grant Nos:10ZCKFGX02300,10ZCKFGX02800)
文摘The permanent-magnet(PM) spherical motor has special configuration and complicated distribution of electromagnetic field.The spatial distribution of the effective flux density produced by permanent magnets is obtained,and the end-effect of the permanent magnets is analyzed.In the 3-dimensional(3-D) finite element(FE) analysis,the calculation of Back-EMF charac-teristics of the PM spherical motor needs to be conducted by steps,which leads to large computational burden.A novel ana-lyzing method to quantize the end-effect of the PM spherical motor is proposed,that is,the end-effect coefficient of the PM spherical motor is calculated to revise the back-EMF waveform obtained from the 2-D FE model.Under different outer radii of the stator coil and different pole arc coefficients of the PM spherical motor,the revised 2-D results are validated by the results obtained from the 3-D FE model and the experimental results.With this method,the special structural feature of the PM spherical motor is fully considered;the pure 3-D calculation of electromagnetic field is conducted only once;higher precision and less computational burden can be achieved.The method provides a new approach to investigating the back-EMF charac-teristic of the PM spherical motor.
