A new method to compensate the end effect of a linear induction motor （LIM） in low-speed maglev vehicles is proposed. With this method, the motors are close to each other so that the front motor＇s exit-end magnetic...A new method to compensate the end effect of a linear induction motor （LIM） in low-speed maglev vehicles is proposed. With this method, the motors are close to each other so that the front motor＇s exit-end magnetic field extends into the next motor＇s entry zone. As a result, the motor＇s magnetic field traveling wave become continuous and the end effect of short primary LIMs is greatly weakened. In the analysis of the air-gap magnetic field distribution, the LIM is assumedly divided into two identical motors vcith the distances of 20, 40, 60, and gO ram. The results show that the air-gap magnetic field is still continuous within these distances due to LIM＇s end effect. As the distance between two motors increases, the distortion of the air-gap magnetic field becomes more severe. Then, we investigate the relationship between the secondary speed and the thrust in three cases, i.e., a single LIM, two motors divided with 72 mm with pole pitch corrected, and two motors divided with 60 mm without the pole pitch being corrected. We find that the thrust has a small decrease when the speed increases, which means that the magnetic field is already continuous and its amplitude is approximately a constant. Furthermore, the thrust loss of case 3 is more than that of case 2, which indicates that the pole pitch correction is effective.展开更多
The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model wi...The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model with compensation of large end effect is constructed when the end effect force at synchronism is of braking character. The equivalent circuit model is used for secondary-flux oriented control of LIM. Single neuron network PI unit for LIM servo-drive is also discussed. The effectiveness of mathematical model for drive control is verified by simulations.展开更多
长初级双边型直线感应电动机(double-sided linear induction motor,DSLIM)的运行方式和边界条件与短初级DSLIM不同,因而纵向边端效应对电机性能的影响存在较大差异。依据电磁场理论对长初级DSLIM的动态纵向边端效应进行分析,导出了电...长初级双边型直线感应电动机(double-sided linear induction motor,DSLIM)的运行方式和边界条件与短初级DSLIM不同,因而纵向边端效应对电机性能的影响存在较大差异。依据电磁场理论对长初级DSLIM的动态纵向边端效应进行分析,导出了电机的等效电路模型及其修正系数,结果表明该类型电机在高速运行时纵向边端效应并不明显,通过选择合适的次级极数和工作转差率,长初级DSLIM的纵向边端效应将远小于短初级DSLIM。利用MAXWELL3D软件构建了电机的三维有限元分析模型,得到了电机的气隙磁场分布和电磁推力曲线。设计实验用原型样机进行了实验,验证了等效电路模型的有效性和实用性。展开更多
静态纵向边端效应是直线电机铁心和绕组开断所致的固有特性之一,对于多段长初级双边直线感应电动机(double-sided linear induction motor,DLIM),其分段供电方式导致电机铁心长度大于通电绕组长度。针对上述特点,该文从理论分析、数字...静态纵向边端效应是直线电机铁心和绕组开断所致的固有特性之一,对于多段长初级双边直线感应电动机(double-sided linear induction motor,DLIM),其分段供电方式导致电机铁心长度大于通电绕组长度。针对上述特点,该文从理论分析、数字仿真的角度研究了电机极数及边端铁心对电机静态纵向边端效应的影响机理同时得到了阻抗矩阵规律。研究结果表明,边端铁心的存在对静态纵向边端效应影响很大,且该效应随着边端铁心长度的增加而作用显著,随着极数的增加,该效应作用减弱;电机阻抗矩阵不再是循环对称矩阵,但可以通过测量三相端口电压电流的幅值和相位方便求解。上述规律的正确性通过峰值功率400kW,最大出力14000N的长初级双边直线感应电动机实验系统进行了验证,为电机数学模型的准确描述和参数的精确提取提供了参考。展开更多
直线电机边端效应是由定子铁心、次级开断所致的固有效应,该效应会引起电机电磁推力的不同频率的脉动。本文首先基于电磁推力公式对边端效应所致的推力脉动频率进行了理论分析。然后利用一维磁路法对动态纵向边端效应引起的次级感应涡...直线电机边端效应是由定子铁心、次级开断所致的固有效应,该效应会引起电机电磁推力的不同频率的脉动。本文首先基于电磁推力公式对边端效应所致的推力脉动频率进行了理论分析。然后利用一维磁路法对动态纵向边端效应引起的次级感应涡流沿轴向的分布规律进行了理论分析和解析计算,根据次级感应涡流进而计算得到了动态纵向边端效应引起的转差频率两倍频推力脉动幅值的解析表达式,并得到了推力脉动幅值和不考虑边端效应时的电磁推力值的比例关系,最后通过峰值功率20 MW,最大出力900 k N的大功率直线感应电动机实验系统对分析结论进行了试验验证。理论分析和试验结果表明:计及边端效应时直线电机电磁推力存在供电频率两倍频和转差频率两倍频的脉动,其中转差频率两倍频的脉动由动态纵向边端效应导致,主要和次级极数以及转差频率有关。展开更多
文摘A new method to compensate the end effect of a linear induction motor （LIM） in low-speed maglev vehicles is proposed. With this method, the motors are close to each other so that the front motor＇s exit-end magnetic field extends into the next motor＇s entry zone. As a result, the motor＇s magnetic field traveling wave become continuous and the end effect of short primary LIMs is greatly weakened. In the analysis of the air-gap magnetic field distribution, the LIM is assumedly divided into two identical motors vcith the distances of 20, 40, 60, and gO ram. The results show that the air-gap magnetic field is still continuous within these distances due to LIM＇s end effect. As the distance between two motors increases, the distortion of the air-gap magnetic field becomes more severe. Then, we investigate the relationship between the secondary speed and the thrust in three cases, i.e., a single LIM, two motors divided with 72 mm with pole pitch corrected, and two motors divided with 60 mm without the pole pitch being corrected. We find that the thrust has a small decrease when the speed increases, which means that the magnetic field is already continuous and its amplitude is approximately a constant. Furthermore, the thrust loss of case 3 is more than that of case 2, which indicates that the pole pitch correction is effective.
基金Project supported by the National Natural Science Foundation of China (No. 50477030) the Natural Science Foundation of Zheji-ang Province (No. Y105351), China
文摘The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model with compensation of large end effect is constructed when the end effect force at synchronism is of braking character. The equivalent circuit model is used for secondary-flux oriented control of LIM. Single neuron network PI unit for LIM servo-drive is also discussed. The effectiveness of mathematical model for drive control is verified by simulations.
文摘长初级双边型直线感应电动机(double-sided linear induction motor,DSLIM)的运行方式和边界条件与短初级DSLIM不同,因而纵向边端效应对电机性能的影响存在较大差异。依据电磁场理论对长初级DSLIM的动态纵向边端效应进行分析,导出了电机的等效电路模型及其修正系数,结果表明该类型电机在高速运行时纵向边端效应并不明显,通过选择合适的次级极数和工作转差率,长初级DSLIM的纵向边端效应将远小于短初级DSLIM。利用MAXWELL3D软件构建了电机的三维有限元分析模型,得到了电机的气隙磁场分布和电磁推力曲线。设计实验用原型样机进行了实验,验证了等效电路模型的有效性和实用性。
文摘静态纵向边端效应是直线电机铁心和绕组开断所致的固有特性之一,对于多段长初级双边直线感应电动机(double-sided linear induction motor,DLIM),其分段供电方式导致电机铁心长度大于通电绕组长度。针对上述特点,该文从理论分析、数字仿真的角度研究了电机极数及边端铁心对电机静态纵向边端效应的影响机理同时得到了阻抗矩阵规律。研究结果表明,边端铁心的存在对静态纵向边端效应影响很大,且该效应随着边端铁心长度的增加而作用显著,随着极数的增加,该效应作用减弱;电机阻抗矩阵不再是循环对称矩阵,但可以通过测量三相端口电压电流的幅值和相位方便求解。上述规律的正确性通过峰值功率400kW,最大出力14000N的长初级双边直线感应电动机实验系统进行了验证,为电机数学模型的准确描述和参数的精确提取提供了参考。
文摘直线电机边端效应是由定子铁心、次级开断所致的固有效应,该效应会引起电机电磁推力的不同频率的脉动。本文首先基于电磁推力公式对边端效应所致的推力脉动频率进行了理论分析。然后利用一维磁路法对动态纵向边端效应引起的次级感应涡流沿轴向的分布规律进行了理论分析和解析计算,根据次级感应涡流进而计算得到了动态纵向边端效应引起的转差频率两倍频推力脉动幅值的解析表达式,并得到了推力脉动幅值和不考虑边端效应时的电磁推力值的比例关系,最后通过峰值功率20 MW,最大出力900 k N的大功率直线感应电动机实验系统对分析结论进行了试验验证。理论分析和试验结果表明:计及边端效应时直线电机电磁推力存在供电频率两倍频和转差频率两倍频的脉动,其中转差频率两倍频的脉动由动态纵向边端效应导致,主要和次级极数以及转差频率有关。
