張文超 張學義 王磊 韓玉桐 顏世龍 許明俊 化思展
摘要 為抑制永磁同步電機齒槽轉矩,減少電機振動與噪聲,提出一種定子齒頂開輔助槽與轉子外圓偏心的結構來抑制齒槽轉矩,提升電機的輸出性能.首先建立了定子齒頂開槽前后與主氣隙分布函數(shù)解析式,分析定子開槽與電機主磁場分布及齒槽轉矩的關系,同時分析了轉子外圓偏心后對齒槽轉矩的影響.以內置3相8極48槽V型永磁同步電機為例,利用有限元法對定子齒頂輔助槽個數(shù)、槽寬、槽深、槽位置以及轉子外圓偏心距等參數(shù)進行優(yōu)化對比分析,獲得最優(yōu)的參數(shù)匹配.結果表明:定子齒頂雙矩形對稱開槽以及轉子外圓偏心的方式能有效改善主氣隙磁場分布,抑制電機齒槽轉矩,優(yōu)化后的電機氣隙磁密5、11、15、17諧波幅值下降明顯,電機齒槽轉矩峰值降低了59.6%,反電勢波形正弦性增強,平均轉矩提升,電機輸出性能明顯改善.關鍵詞 定子輔助槽;齒槽轉矩;主氣隙分布函數(shù);轉子外圓偏心;永磁同步電機
中圖分類號TM351;TM359.9
文獻標志碼A
0 引言
與傳統(tǒng)的電勵磁同步電機相比,稀土永磁同步電機具有結構簡單、運行可靠、體積小、效率高等優(yōu)點,廣泛應用于航空航天、工農生產、新能源汽車等領域[1].但永磁同步電機穩(wěn)定運行時存在齒槽轉矩,會引起電機振動與噪聲,影響電機輸出性能,降低電機運行可靠性與穩(wěn)定性.因此,降低齒槽轉矩,提升電機輸出性能已成為高性能永磁同步電機的重要研究內容之一.
目前,國內外學者對削弱永磁電機齒槽轉矩已進行了大量的研究與分析,取得了一定成果.文獻[2]通過建立參數(shù)化掃描模型,對V型內置式永磁同步電機永磁體夾角、永磁體長寬比、氣隙長度進行仿真分析,得到了考慮以上三個變量的齒槽轉矩最優(yōu)方案;文獻[3]通過偏斜定子降低橫向磁通電機的齒槽轉矩;文獻[4]對轉子分段斜極、非均勻氣隙情況下的內置式永磁同步電機進行齒槽轉矩的削弱;文獻[5]提出一種非對稱V型磁極偏移轉子結構,并通過選擇最佳的磁極偏移方式與角度,達到降低齒槽轉矩的效果;文獻[6]提出一種對定子槽口進行偏移的方法來降低齒槽轉矩,通過偏移適當?shù)慕嵌饶軌蛴行Ы档妄X槽轉矩;文獻[7]以雙層內嵌式永磁同步電機為例,采用磁極偏移與非均勻氣隙的方法來降低齒槽轉矩,并取得理想的效果.此外還有眾多學者利用在電機內部開設輔助槽的方法來降低齒槽轉矩.文獻[8-10]采用永磁同步電機轉子極面開輔助槽削弱齒槽轉矩的方法,通過選擇合適的輔助槽參數(shù),將齒槽轉矩優(yōu)化到最佳效果;文獻[11-13]以內置式永磁同步電機為例,研究了定子開設輔助槽數(shù)量、槽型、尺寸對齒槽轉矩的影響.
目前學者們對削弱齒槽轉矩的研究主要集中在對定子或者轉子單獨進行優(yōu)化上,但對兩者同時進行優(yōu)化的措施相對較少.因此,為降低齒槽轉矩,本文提出一種在定子齒頂開設輔助槽與轉子外圓偏心的組合方法,推導定子開槽時主氣隙長度分布函數(shù)表達式,分析定子開槽數(shù)量、輔助槽間距、輔助槽寬度及其深度對氣隙長度分布函數(shù)、齒槽轉矩的影響,同時對轉子外圓進行偏心處理,推導轉子外圓偏心時與齒槽轉矩之間的關系式.利用有限元法優(yōu)化分析定子輔助槽參數(shù)、轉子外圓偏心參數(shù)及優(yōu)化前后永磁同步電機的輸出性能,驗證分析的有效性.
1 齒槽轉矩原理
1.1 定子齒頂輔助槽與齒槽轉矩關系分析
1.1.1 定子齒輔助槽槽數(shù)與齒槽轉矩的關系
1.1.2 定子齒頂開槽主氣隙長度分布函數(shù)解析計算
1.2 轉子外圓偏心與齒槽轉矩關系解析
2 齒槽轉矩削弱分析
2.1 定子齒頂開槽數(shù)量對齒槽轉矩的影響
2.2 定子齒頂開槽形狀對齒槽轉矩的影響
不同輔助槽型對齒槽轉矩的影響有所差異,本文對比研究三角形槽、半圓形槽、矩形槽三種輔助槽型對齒槽轉矩的影響規(guī)律,三種槽型如圖6所示,保證三者的槽深與槽寬相同,仿真不同輔助槽型的齒槽轉矩波形如圖7所示.
由圖7可知,定子齒頂輔助槽不同槽型對電機齒槽轉矩的削弱效果不同,三角形、圓形、矩形三種輔助槽型對應的齒槽轉矩峰值分別為0.91、0.85和0.82 N·m,其中矩形槽對齒槽轉矩的削弱效果最明顯,因此本文選擇矩形輔助槽.
2.3 輔助槽與定子齒中心線角度γ對齒槽轉矩的影響
2.4 輔助槽槽寬a對齒槽轉矩的影響
2.5 輔助槽槽深b對齒槽轉矩的影響
2.6 偏心距h對齒槽轉矩的影響
3 優(yōu)化結果分析
采用優(yōu)化后的定子齒頂輔助槽與轉子外圓偏心距參數(shù)建立電機模型,仿真得到優(yōu)化前后的齒槽轉矩對比如圖13所示.
由圖13可知,優(yōu)化后的齒槽轉矩峰值與開槽前相比顯著降低,由1.14 N·m下降到0.46 N·m,降低了59.6%,優(yōu)化效果明顯.優(yōu)化前后的氣隙磁密以及氣隙磁密諧波對比如圖14和圖15所示.
由圖14和圖15可知,優(yōu)化后的氣隙磁密波形正弦性增強,峰值有所提升,相比于優(yōu)化前,氣隙磁密基波幅值略有增加,5、11、15、17次諧波幅值明顯下降.優(yōu)化前后反電動勢波形以及諧波對比如圖16和圖17所示.
由圖16和圖17可知,相對于優(yōu)化前,優(yōu)化后的反電動勢波形走勢更趨于正弦,峰值略有提升,反電動勢基波幅值略有提升,9、11、13次諧波明顯下降.優(yōu)化前后的電機輸出轉矩如圖18所示,優(yōu)化前后目標參數(shù)對比如表2所示.
由圖18和表2可知,定子齒頂開輔助槽優(yōu)化后,電機的轉矩峰值由240.32 N·m提高到251.69 N·m,提升4.7%,平均轉矩由220.94 N·m提高到231.65 N·m,提升4.8%,電機的轉矩脈動系數(shù)由9.4%下降到8.5%,與優(yōu)化前相比降低9.6%,驅動電機輸出性能顯著提升.
4 結論
本文提出一種定子齒頂開設輔助槽與轉子外圓偏心的組合方法來削弱永磁同步電機的齒槽轉矩,詳細推導了開槽前后的氣隙長度分布函數(shù),對比研究定子齒輔助槽對齒槽轉矩的影響,同時分析了轉子外圓偏心對齒槽轉矩產生的影響.利用有限元法對開槽數(shù)量、形狀、位置、槽寬、槽深等輔助槽參數(shù)與轉子偏心距進行優(yōu)化對比分析.結果表明,當定子齒頂開兩個矩形輔助槽,輔助槽與定子齒中心線角度為1.6°,槽寬為1.4 mm,槽深為0.4 mm,轉子外圓偏心距為10 mm時,齒槽轉矩峰值降低了59.6%,電機齒槽轉矩明顯削弱,優(yōu)化后氣隙磁密諧波幅值降低,反電動勢正弦性增強,平均轉矩提升4.8%,轉矩脈動降低9.6%,電機的輸出性能改善.
參考文獻
References
[1]唐任遠.現(xiàn)代永磁電機:理論與設計[M].北京:機械工業(yè)出版社,1997:161-215
[2] 姚學松,王瑛,陳士剛,等.V型內置式永磁同步電機的齒槽轉矩研究[J].微電機,2020,53(9):28-32YAO Xuesong,WANG Ying,CHEN Shigang,et al.Research on cogging torque of V-type interior permanent magnet synchronous motor[J].Micromotors,2020,53(9):28-32
[3] Taravat S,Kiyoumarsi A,Bracikowski N.Mitigation of cogging torque in transverse-flux permanent-magnet machines with flux concentrators by step skewing of stator pole[J].IET Electric Power Applications,2020,14(12):2378-2388
[4] 黃燕濤,郭新華,項雷軍.內置式永磁電機齒槽轉矩的優(yōu)化設計[J].華僑大學學報(自然科學版),2016,37(5):536-540HUANG Yantao,GUO Xinhua,XIANG Leijun.Optimal design of cogging torque of interior permanent magnet motor[J].Journal of Huaqiao University (Natural Science),2016,37(5):536-540
[5] 高鋒陽,李曉峰,齊曉東,等.非對稱V型磁極偏移內置式永磁同步電機轉矩脈動分析[J].電機與控制學報,2021,25(9):112-120GAO Fengyang,LI Xiaofeng,QI Xiaodong,et al.Analysis of torque ripple of the interior permanent magnet synchronous motor with asymmetric V-pole offset[J].Electric Machines and Control,2021,25(9):112-120
[6] 談書志,張衛(wèi),唐楊,等.槽口偏移對永磁電機齒槽轉矩抑制的分析[J].組合機床與自動化加工技術,2019(10):49-52TAN Shuzhi,ZHANG Wei,TANG Yang,et al.Research and analysis of cogging torque reduction of PMBLDC motor based on notch offset[J].Modular Machine Tool & Automatic Manufacturing Technique,2019(10):49-52
[7] 王傳真,張學義,王平,等.雙層內嵌式永磁同步電機齒槽轉矩優(yōu)化[J].中國科技論文,2021,16(8):906-910WANG Chuanzhen,ZHANG Xueyi,WANG Ping,et al.Cogging torque optimization of double-layer interior permanent magnet synchronous motor[J].China Sciencepaper,2021,16(8):906-910
[8] 徐士強,張學義,王平,等.一種削弱電動汽車內嵌永磁同步電機齒槽轉矩的方法[J].中國科技論文,2020,15(8):942-947XU Shiqiang,ZHANG Xueyi,WANG Ping,et al.A method for weakening cogging torque of interior permanent magnet synchronous motor in electric vehicle[J].China Sciencepaper,2020,15(8):942-947
[9] 陳鑫,李國麗,錢喆,等.轉子開輔助槽削弱雙層內置式永磁同步電機轉矩脈動[J].微電機,2020,53(10):1-4,16CHEN Xin,LI Guoli,QIAN Zhe,et al.Rotor auxiliary slot method reduces torque ripple of double-layer interior permanent magnet motor[J].Micromotors,2020,53(10):1-4,16
[10] 蔣迪元,單文桃,潘玉成.轉子輔助槽對高速電主軸齒槽轉矩的影響機理研究[J].噪聲與振動控制,2021,41(1):37-40,65JIANG Diyuan,SHAN Wentao,PAN Yucheng.Study on influence of rotor auxiliary groove on gear groove torque of high speed motorized spindles[J].Noise and Vibration Control,2021,41(1):37-40,65
[11] 夏加寬,于冰.定子齒開輔助槽抑制永磁電動機定位力矩[J].微特電機,2010,38(1):13-14,23XIA Jiakuan,YU Bing.Study on reducing cogging torque of permanent magent motors by stator teeth notching[J].Small & Special Electrical Machines,2010,38(1):13-14,23
[12] 古海江,黃文美,王超,等.定子齒開槽對內置式永磁電機齒槽轉矩的影響[J].電機與控制應用,2016,43(8):40-45GU Haijiang,HUANG Wenmei,WANG Chao,et al.Influence of stator teeth notching on cogging torque of interior permanent magnet motor[J].Electric Machines & Control Application,2016,43(8):40-45
[13] 王軼楠,唐沖,顏鋼鋒.定子齒冠開輔助凹槽抑制永磁電機齒槽轉矩[J].微電機,2014,47(10):20-23WANG Yinan,TANG Chong,YAN Gangfeng.Reducing cogging torque of permanent magnet motors by notching auxiliary slot in top of stator teeth[J].Micromotors,2014,47(10):20-23
[14] 王秀和.永磁電機[M].北京:中國電力出版社,2007:80-84
[15] 劉東浩,張小平,郭宇軒,等.基于內切圓弧的交流牽引電機齒肩削角降噪方法[J].電工技術學報,2021,36(6):1259-1268LIU Donghao,ZHANG Xiaoping,GUO Yuxuan,et al.Method for reducing shoulder noise of AC traction motor based on inscribed arc[J].Transactions of China Electrotechnical Society,2021,36(6):1259-1268
[16] 李巖,李雙鵬,周吉威,等.基于定子齒削角的近極槽永磁同步電機振動噪聲削弱方法[J].電工技術學報,2015,30(6):45-52LI Yan,LI Shuangpeng,ZHOU Jiwei,et al.Weakening approach of the vibration and noise based on the stator tooth chamfering in PMSM with similar number of poles and slots[J].Transactions of China Electrotechnical Society,2015,30(6):45-52
[17] 馬世倫,張學義,耿慧慧,等.電動汽車新型永磁同步電機的非均勻氣隙建模及性能分析[J].西安交通大學學報,2019,53(1):70-76MA Shilun,ZHANG Xueyi,GENG Huihui,et al.Modeling and performance analysis for non-uniform air gap in new type of permanent magnet synchronous motor of electric vehicle[J].Journal of Xian Jiaotong University,2019,53(1):70-76
Weakening cogging torque of built-in permanent magnet synchronous motor
ZHANG Wenchao ZHANG Xueyi WANG Lei HAN Yutong
YAN Shilong XU Mingjun HUA Sizhan
1School of Transportation and Vehicle Engineering,Shandong University of Technology,Zibo 255000
2Weifang Electric Motor Factory Co. Ltd,Weifang 262100
3Shandong Hapvoo Power Technology Co. Ltd,Zibo 255000
Abstract A structure of stator tooth jacking auxiliary slot and rotor outer circle eccentricity was proposed for Permanent Magnet Synchronous Motor (PMSM) to suppress the cogging torque and reduce the vibration and noise of motor thus improve the output performance of PMSM.The analytical formula of distribution function was established for the stator tooth top (before and after slotting) and the main air gap,thus clarified the relationships between the stator slotting and the main magnetic field distribution as well as the cogging torque.At the same time,the influence of the rotor outer circle eccentricity on the cogging torque was analyzed.The optimal parameter matching was obtained through optimization tests and comparative analysis of auxiliary slot parameters including slot number,width,depth,slot spacing and rotor outer circle eccentricity,via finite element method on a built-in 3-phase 8-pole 48-slot V-type PMSM.The results showed that the double rectangular symmetrical slotting on the stator tooth top and the eccentricity of the rotor outer circle can effectively improve the magnetic field distribution of the main air gap and restrain the cogging torque of the motor.The harmonic amplitude of the optimized air gap magnetic density 5,11,15 and 17 was decreased significantly,the peak value of the cogging torque of the motor was decreased by 59.6%,and the sine of the back EMF waveform as well as the average torque was increased,thus the motors output performance was significantly improved.
Key words stator auxiliary slot;cogging torque;principal air gap distribution function;rotor outer circle eccentricity;permanent magnet synchronous motor (PMSM)