Nowadays, electronic devices are more and more integrated into everyday life. These seamless integrations focus on mobility, but at the same time strive to be unobtrusive to the end user. With the introduction of pers...Nowadays, electronic devices are more and more integrated into everyday life. These seamless integrations focus on mobility, but at the same time strive to be unobtrusive to the end user. With the introduction of personal data assistants and intelligent cellular phones for the searching of the website, true mobile computing is closer than ever. However, battery technology, which powers most of these mobile connectivity solutions, has not kept up the same pace of improvement. The paper describes a methodology for the design and performance of a self-excited permanent-magnet generator applied to low power supplies. It combines an analytical field model, a lumped reluctance equivalent magnetic circuit, and an equivalent electrical circuit. An illustrated example of a 15-mW, 290-r/min generator is given, and the analysis techniques are validated by measurements on a prototype system.展开更多
在有铁心永磁直线电机(permanent magnet linear machines,PMLM)初级匝间短路故障分析中,对初级短路环电流的分析十分重要。该文提出采用磁动势–气隙磁导模型与电枢绕组故障等效模型结合的解析方法,计算任意初级位置发生的匝间短路故...在有铁心永磁直线电机(permanent magnet linear machines,PMLM)初级匝间短路故障分析中,对初级短路环电流的分析十分重要。该文提出采用磁动势–气隙磁导模型与电枢绕组故障等效模型结合的解析方法,计算任意初级位置发生的匝间短路故障短路环电流。首先根据永磁、电枢磁动势与开槽情况下的气隙磁导函数分别计算通过短路环的永磁、电枢磁链,然后通过矢量合成法得到短路环中的实际磁链以及瞬时短路电流。基于有限元方法证明解析法的正确性并探究不同短路故障匝数、不同短路故障位置对电机性能如短路环电流、相电流、推力的影响。最后制造一台样机验证有限元分析、解析法计算结果的正确性。展开更多
为更加精确、快速地分析高速磁浮悬浮电磁铁的电磁力特性,实现与控制、动力学模型的良好匹配,提出一种基于非线性材料的高速磁浮悬浮电磁铁电磁力建模方法.首先,在搭建电磁铁等效磁路(equivalent magnetic circuit,EMC)模型时,考虑了导...为更加精确、快速地分析高速磁浮悬浮电磁铁的电磁力特性,实现与控制、动力学模型的良好匹配,提出一种基于非线性材料的高速磁浮悬浮电磁铁电磁力建模方法.首先,在搭建电磁铁等效磁路(equivalent magnetic circuit,EMC)模型时,考虑了导磁材料自身的非线性,导磁材料的磁阻计算以内部磁通为基础,推导以电压及间隙为输入,电流及电磁力为输出的电磁铁解析模型,计算电磁力-间隙-电流特性,并与传统EMC模型进行对比分析;其次,搭建电磁铁有限元(finite element method,FEM)模型,对非线性EMC模型的结果进行验证;最后,采用地面试验台对悬浮电磁铁进行电磁力测试,验证EMC及FEM模型的准确性.研究结果表明:与传统电磁力模型相比,本文EMC模型计算的电磁力在大电流区间会出现饱和现象,更接近实际情况,适用范围更广;磁间隙12.5 mm,电流50 A工况下,EMC与FME计算的电磁力偏差仅为4.5%,且与试验结果具有非常高的一致性;高精度的非线性电磁力模型为悬浮系统动态特性联合分析及参数优化奠定了基础.展开更多
Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnet...Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnetic potential of the air gap magnetic field considering the slot effect is calculated.On the basis of the discrete current element and magnetic equivalent circuit model,the local magnetic saturation effect of the stator and rotor is quantitatively simulated and the air gap magnetic field intensity distribution is obtained via numerical simulation.A series of uniformly distributed equivalent electromagnetic springs are introduced to develop an electromagnetic–structural coupling finite element PMDG model.The proposed air gap field analysis method is verified by the finite element analysis results.On the basis of the test platform for the Goldwind 1.5MW PMDG,both modal and dynamic response tests for the stator/rotor coupling system are conducted,and the results are compared with the natural frequencies,mode shapes,and vibration responses obtained using the numerical model.The effects of the air gap length and rotor speed on the natural frequencies of the coupling system are analyzed.The proposed model has the potential to accurately evaluate the PMDG vibration energy,avoiding resonance points,and maintaining stable operations of the unit.展开更多
文摘Nowadays, electronic devices are more and more integrated into everyday life. These seamless integrations focus on mobility, but at the same time strive to be unobtrusive to the end user. With the introduction of personal data assistants and intelligent cellular phones for the searching of the website, true mobile computing is closer than ever. However, battery technology, which powers most of these mobile connectivity solutions, has not kept up the same pace of improvement. The paper describes a methodology for the design and performance of a self-excited permanent-magnet generator applied to low power supplies. It combines an analytical field model, a lumped reluctance equivalent magnetic circuit, and an equivalent electrical circuit. An illustrated example of a 15-mW, 290-r/min generator is given, and the analysis techniques are validated by measurements on a prototype system.
文摘在有铁心永磁直线电机(permanent magnet linear machines,PMLM)初级匝间短路故障分析中,对初级短路环电流的分析十分重要。该文提出采用磁动势–气隙磁导模型与电枢绕组故障等效模型结合的解析方法,计算任意初级位置发生的匝间短路故障短路环电流。首先根据永磁、电枢磁动势与开槽情况下的气隙磁导函数分别计算通过短路环的永磁、电枢磁链,然后通过矢量合成法得到短路环中的实际磁链以及瞬时短路电流。基于有限元方法证明解析法的正确性并探究不同短路故障匝数、不同短路故障位置对电机性能如短路环电流、相电流、推力的影响。最后制造一台样机验证有限元分析、解析法计算结果的正确性。
文摘为更加精确、快速地分析高速磁浮悬浮电磁铁的电磁力特性,实现与控制、动力学模型的良好匹配,提出一种基于非线性材料的高速磁浮悬浮电磁铁电磁力建模方法.首先,在搭建电磁铁等效磁路(equivalent magnetic circuit,EMC)模型时,考虑了导磁材料自身的非线性,导磁材料的磁阻计算以内部磁通为基础,推导以电压及间隙为输入,电流及电磁力为输出的电磁铁解析模型,计算电磁力-间隙-电流特性,并与传统EMC模型进行对比分析;其次,搭建电磁铁有限元(finite element method,FEM)模型,对非线性EMC模型的结果进行验证;最后,采用地面试验台对悬浮电磁铁进行电磁力测试,验证EMC及FEM模型的准确性.研究结果表明:与传统电磁力模型相比,本文EMC模型计算的电磁力在大电流区间会出现饱和现象,更接近实际情况,适用范围更广;磁间隙12.5 mm,电流50 A工况下,EMC与FME计算的电磁力偏差仅为4.5%,且与试验结果具有非常高的一致性;高精度的非线性电磁力模型为悬浮系统动态特性联合分析及参数优化奠定了基础.
基金National Natural Science Foundation of China,Grant/Award Numbers:11872222,11902173State Key Laboratory of Tribology,Grant/Award Number:SKLT2021D11。
文摘Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnetic potential of the air gap magnetic field considering the slot effect is calculated.On the basis of the discrete current element and magnetic equivalent circuit model,the local magnetic saturation effect of the stator and rotor is quantitatively simulated and the air gap magnetic field intensity distribution is obtained via numerical simulation.A series of uniformly distributed equivalent electromagnetic springs are introduced to develop an electromagnetic–structural coupling finite element PMDG model.The proposed air gap field analysis method is verified by the finite element analysis results.On the basis of the test platform for the Goldwind 1.5MW PMDG,both modal and dynamic response tests for the stator/rotor coupling system are conducted,and the results are compared with the natural frequencies,mode shapes,and vibration responses obtained using the numerical model.The effects of the air gap length and rotor speed on the natural frequencies of the coupling system are analyzed.The proposed model has the potential to accurately evaluate the PMDG vibration energy,avoiding resonance points,and maintaining stable operations of the unit.
