电动拖拉机PC-DSPM电机电子变极策略与分析  

Electronic pole-changing strategy and analysis for PC-DSPM motor in electric tractors

作　　者：杜怿[1] 孙旭 孙延东 肖凤[1] 朱孝勇[1] 毛怡 严序康 DU Yi;SUN Xu;SUN Yandong;XIAO Feng;ZHU Xiaoyong;MAO Yi;YAN Xukang(School of Electrical and Information Engineering,Jiangsu University,Zhenjiang 212013,China;China Automotive Innovation Corporation,Nanjing 211100,China)

机构地区：[1]江苏大学电气信息工程学院,镇江212013 [2]中汽创智科技有限公司,南京211100

出　　处：《农业工程学报》2023年第8期44-53,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(52177045);江苏省农业科技自主创新资金项目(CX(21)3147);江苏高校优势学科建设工程(三期)资助项目(PAPD-2018-87)。

摘　　要：针对田间作业和转场运输等不同工况时的行驶速度需求,该研究提出使用双凸极变极永磁(pole-changing doubly-salient permanent magnet,PC-DSPM)电机作为电动拖拉机的驱动电机,通过变极获得驱动电机的多种机械特性。基于气隙磁场调制理论,将PC-DSPM电机气隙磁场中的主要工作谐波分为2组,采用电子变极改变电枢绕组连接方式,从而选择不同组别的气隙磁场谐波参与机电能量转换,形成PC-DSPM电机3种运行模式。根据不同模式下的转矩-转速曲线,选取电机在恒功率区的2个变极切换点,并据此将拖拉机的运行速度划分为0~7.7、7.7~10.5和10.5~32.7 km/h共3个区间。为实现平滑变极,构建自抗扰控制和跟踪微分器的PC-DSPM电机变极策略。与采用自抗扰控制的阶跃响应变极相比,虽然2个切换点处的变极时间分别延长至400和600 ms,但变极过程中dq轴电流过渡平稳,转矩波动分别下降8.5%和11.8%,转速恒定在920和1 250 r/min。研究结果可为实现电动拖拉机多工况高效运行及变极永磁电机平滑切换提供理论参考。Benefiting from driving by an electric motor,an electric tractor is one of the most effective means to realize green agricultural production with high efficiency,zero emission,and low noise.The field and road operating conditions can usually occur in electric tractors.Specifically,the typical speed of the former is 2-7,and 7-10 km/h,whereas,the latter is mainly used in the condition of transportation with the speed of 20-35 km/h.The speed of an electric tractor can be in the discrete form in the very wide range of speed regulation.In this study,a pole-changing doubly-salient permanent magnet(PC-DSPM)motor was proposed using the PC operation.Different output characteristics were also obtained to meet the special operation of electric tractors.The working components were firstly selected as the 2,4,10,and 16 pole-pairs harmonics with the higher amplitude,according to the general air-gap field modulation.Then,four working harmonics were divided into two groups,in terms of the slot pitch angles.As such,the coil electromotive force(EMF)phasor graphs under the working harmonics of Group 1 were totally different from that of Group 2,in order to achieve the PC operation using different winding connections.Three kinds of armature winding connections were then designed using the coil EMF phasor graphs.Thus,three operating modes of the PC-DSPM motor were achieved to select one or two groups of working harmonics in the electromechanical energy conversion using the filtering effect of armature winding.Two PC switching points were determined in the constant power region with the mechanical characteristic curves of the PC-DSPM motor under three modes.The motor speed was divided into low(0-920 r/min),medium(920-1250 r/min),and high speed(1250-3900 r/min).In terms of the gear-box with a fixed ratio of 18 and the wheels with a diameter of 0.8 m,the speeds of electric tractors in the three modes were 0-7.7,7.7-10.5,and 10.5-32.7 km/h,respectively,in order to meet the speed demands of field and road operations.Furthermore,an electro

关 键 词：拖拉机 永磁电机 电子变极 六桥臂逆变器 跟踪微分器 

分 类 号：S219.4[农业科学—农业机械化工程] TM351[农业科学—农业工程]