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在分析步进电机数学模型和细分原理基础上,对自适应控制技术在步进电机中的应用进行了研究,设计了以PIC16F877单片机和L6219驱动芯片为核心的控制与驱动单元,采用自适应细分控制算法的多轴运动控制系统,解决步进电机在低频运行时转矩脉动、细分切换引起速度突变和宽广范围内速度平滑控制问题。给出了控制系统的主要硬件电路以及软件设计方案和相应的流程图,最后在实际控制步进电机运行的基础上给出了步进电机运行时的细分控制电流的波形和电机绕组电流的波形。实验表明电流波形合理,步进电机宽广运行平滑且噪音低,性能良好。 相似文献
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内置式永磁同步电机,其速度运行范围与电机参数息息相关。本文从电机本身参数的角度出发,充分考虑电机实际运行的两个约束条件:电压极限椭圆和电流极限圆,对实验室电机进行分析,提出了一种基于MTPA的弱磁控制算法。在低速区,利用曲线拟合,解决了MTPA控制算法中d、q轴电流给定值无法获得解析解的问题,得到了不同转速要求时的交直轴电流给定值。在高速区,利用转矩的梯度和电压差对MTPA指令进行修正,对电机进行弱磁控制。理论、仿真和实验结果表明,在特定电机参数下,i_d=0的矢量控制无法使电机达到额定运行状态,而本文所提出的基于MTPA的弱磁算法,既满足了电机的额定运行状态,同时提高了电机的带载能力,拓宽了电机的调速范围。 相似文献
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采用分段式长定子永磁直线同步电机牵引的中速磁悬浮列车在定子段换步时,相邻定子段绕组交链的永磁磁链的改变会导致牵引力损失,除此以外,在牵引过程中,馈电电缆长度的增加使得电机漏阻抗增大,在变流器供电容量的限制下,列车无法在试验线中完成全速度运行。该文首先建立含有定子段换步的长定子永磁直线同步电机数学模型,在此基础上,提出全速度运行的换步控制策略,以及适用于该电机的弱磁控制策略。该策略对q轴电流实时分配,保证在换步区间相邻定子段的q轴电流均跟随参考值;利用电机端电压计算得到d轴电流参考值,使电机在id=0控制和弱磁控制两种工况之间平滑切换。通过硬件在环实验,验证了采用所提策略可在线路长度和变流器容量限制下,实现列车全速度运行,并消除电机在定子段换步时的牵引力损失。 相似文献
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The shielding effectiveness of thin-walled hollow cylinders of finite length in a homogeneous magnetic field with arbitrary
direction is determined analytically. Both cylinders with finite conductivity and superconducting as well as ferromagnetic
cylinders are examined for this purpose. As a result, the screening attenuation on the axis of a superconducting cylinder
in a longitudinal magnetic field turned out to be identical with the screening attenuation on the axis of a ferromagnetic
cylinder with a transverse magnetic field. We show how to determine the corresponding values along the cylinder axis on the
basis of the shielding in the cylinder center by way of simple approximations. To illustrate the analysis, the lines of magnetic
flux for longitudinal field incidence, the equipotential lines for transversal field incidence and the lines of induced eddy
currents for the case of a conducting cylinder are shown. 相似文献
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交通牵引大功率单边直线感应电机性能研究 总被引:1,自引:1,他引:0
从单边直线感应电机(SLIM)气隙磁密方程入手,引入绕组函数方法,将次级绕组分为基波和边端效应波分量。根据初级绕组分布,推导出两相静止坐标下的初级绕组函数,解出次级绕组基波和边缘效应波分量。由绕组函数理论计算出电感、品质因数、次级电阻和运动电势系数,建立电压和磁链方程。根据初次级能量转换关系,得到推力方程。通过恒流恒频下的暂态特性和几种变频模式下的稳态特性计算,比较了实际稳态运行中的大功率SLIM的相电流、推力和效率的计算值和测量值。结果表明,绕组函数法能较好地描述边端效应,得到的稳态推力、效率和试验基本吻合,并证明了暂态计算的真实性。该模型可用于电机设计和特性分析中,具有一定的实用性。 相似文献
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ABSTRACT Eddy currents in the quadrature axis of O.C. machines, which arise in nonstationary conditions, affect the performance of the machine considerably. The nonlminated yoke of O.C. machine carry eddy currents, and the quadrature axis components of their M.M.F's are very important in analysing machine performance. For example the importance of these M.F.F. components in performance of the machine is evident from the fact that the normal commutation of machine may be severely disturbed due to their damping action on the magnetic field in the zone of commutation. But the yoke of D.C. machines due to its position in the magnetic circuit does not distribute its flux symmetrically in its radial section. This phenomenon, which is not considered in the publications, may perceptibly change the mathematical model, describing the effects of quadrature axis M.M.F. on the machine performance. But its mathematical consideration should be rational and easy in programming for computer analysis. In the present article the above mentioned task is performed. 相似文献
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针对永磁盘式无铁心同步电机的轴向磁场结构,在现有Halbach永磁阵列的基础上,提出一种梯形结构永磁体阵列。详细阐述该电机的结构与优点,利用有限元方法研究了不同梯形结构永磁体阵列对气隙磁密的影响,根据气隙磁场中的谐波含量及空载反电势畸变率选取最优转子结构。该结构在保证与传统结构永磁体材料用量相当的前提下,有效提高气隙磁密的基波,降低谐波含量。由于轴向磁场结构的特殊性,给出该电机的设计规则,如磁极尺寸和导体占空比的确定。计算了电机在负载工况下不同定子电流对交直轴电感的影响,为该类电机的设计提供了一定的参考价值。 相似文献
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根据永磁同步电机(PermanentMagnetSynchronousMotor-PMSM)特点,设计并实现了其双CPU控制的数字伺服系统。利用数字信号处理器(DSP)芯片和复杂可编程逻辑器件(CPLD)芯片分别实现了电流检测模块、转子位置和转速辨识模块、触发脉冲生成模块。提出了一种基于位置模糊控制策略的启动方法,有效解决了传统直流转矩定位方法的转子退磁问题。最后采用空间电压矢量法(SVPWM),通过C语言编程实现了永磁同步电机的转速调节,实验结果表明系统具有良好的动态响应和稳态性能。 相似文献
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Kazuhiro Nishimura 《Electrical Engineering in Japan》2021,214(1):18-25
The strong magnetic field arrays by using cubic permanent magnets are proposed as a magnetic field source. The magnets used two types of the magnetized directions: 6 and 18 directions. The array is three‐dimensional structure: cube consisting of three, five, seven, and nine cubic magnets on the side. There are two types of the structures: through‐hole and dead end in the center. For each cube magnet, the magnetic flux density of the center was calculated by the derived formulae, which are solved the area integral by the integral formulae. It is a feature that the calculations are fast. The directions in which the magnetic flux density of the z‐axis is maximized were selected, and the sum of their magnetic flux density was obtained. At the same time, each sum of the magnetic flux density of the x‐axis and y‐axis was selected to be zero. It was found that the obtained results are independent of the length of one side. Therefore, the structures can also be combined to cover the structures. Although the operating point of the magnet is not taken into account, it was able to find the arrangements of more than 2 T. It was confirmed that the array of 24 cubes was consistent with the experiment. 相似文献
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内置式永磁同步电机(IPMSM)以高转矩电流比、更宽的调速区间、高功率密度、高效率等优点在电动汽车领域应用广泛。电动汽车用IPMSM磁路结构复杂,饱和程度高,造成交直轴磁路的交叉耦合,使得交直轴之间产生互感。对交叉耦合现象进行了磁路分析,阐述了其对磁链和电感参数的影响。采用冻结磁导率法(FPM)和有限元法(FEM)对交直轴电感进行计算,并对电感参数随电流变化情况进行了定量分析。对比2种计算方法得出的交直轴电感参数,发现计算结果吻合较好。最后,对比分析了2种方法计算交直轴电感的优缺点,分析表明以FEM为主FPM为辅计算交直轴电感参数,能保证电感参数的精确度,缩短计算时间。 相似文献