高精度永磁直线伺服电机法向力波动分析与抑制方法研究

发布时间：2018-07-16 21:04

【摘要】：直线电机直接驱动技术极大地提高了伺服系统的快速反应能力、运动精度和高速进给能力，已成为现代高档数控机床最具代表性的先进技术之一。单边平板型有铁心伺服用永磁直线同步电机（PMLSM）由于具有推力大，功率密度高的特点，是目前应用最为广泛的一种直线电机，但由于齿槽效应、端部效应及磁场谐波的影响，电机在运行过程中初、次级之间存在较大的法向力波动，法向力的波动引起的摩擦力摄动和机床振动极大地影响了机床的加工精度。本文针对平板型有铁心PMLSM法向力波动的产生机理及削弱方法进行了系统的研究，主要内容如下：研究PMLSM法向力波动与磁场各次谐波之间的关系以及法向力与推力之间相关性。在分析永磁体磁动势谐波、电枢反应磁动势谐波以及气隙磁导谐波的基础上，根据Maxwell Stress Tensor法和积分法推导初级端齿无限长PMLSM法向力波动的解析表达式，揭示法向力波动的规律。接着从气隙磁场储能的角度，通过解析法分析法向力与切向电磁推力的相关性，综合考虑削弱齿槽效应、端部效应以及负载扰动引起的法向力波动的方法对切向电磁推力的影响。研究电机参数对法向力波动的影响规律。齿顶宽度、极弧系数对法向力波动有直接的关系，首先解析分析齿顶宽度、极弧系数对齿槽效应引起的法向力波动（简称为齿槽法向力波动）幅值和次数的影响规律；然后采用有限元法验证不同齿顶宽度和不同极弧系数下的齿槽法向力波动情况以及对推力性能的影响程度，为高性能直线电机优化设计提供理论指导。研究永磁磁极三段错位削弱齿槽法向力波动的方法。首先分析电机初级齿顶开辅助槽和不等极弧系数组合削弱推力波动的方法对削弱法向力波动的规律，进而分析这两种方法的局限性；在此基础上，根据相位反相抵消的原理，提出永磁磁极三段错位法削弱甚至抵消主要次谐波齿槽法向力波动，同时避免电机产生横向俯仰运动，并采用有限元分析法验证该方法的有效性。研究分相电流补偿控制策略削弱端部效应引起法向力波动（简称为端部法向力波动）的方法。端部法向力波动是法向力波动的主要分量，，根据分数槽绕组永磁直线伺服电机三相绕组的特殊分布规律，提出了抑制端部法向力波动的分相电流补偿控制策略，在分相电流补偿控制时，遵循推力性能最优、法向力波动最小的原则；接着研究了端部法向力波动的补偿模型建模方法；最后采用Ansoft系列软件Simplorer和Maxwell联合仿真验证该补偿控制策略的有效性。设计永磁直线伺服电动机样机以及法向力测试系统验证理论和方法的正确性。针对初级端齿无限长12槽8极整体磁极及三段错位磁极PMLSM的法向力进行稳态测量，验证磁极三段错位法削弱齿槽法向力波动的有效性；针对分相电流补偿控制的12槽11极PMLSM进行法向力测试，验证分相电流补偿控制策略削弱端部法向力波动的可行性和有效性。
[Abstract]:The direct drive technology of linear motor has greatly improved the fast response ability of the servo system, and has become one of the most representative advanced technologies in modern high grade CNC machine tools. The single side plate type PMLSM has the characteristics of high thrust and high power density. It is one of the most widely used linear motors at present. However, due to the effect of the cogging effect, end effect and magnetic field harmonic, there is a large normal force fluctuation between the initial and secondary stages of the motor. The friction perturbation and machine vibration caused by the fluctuation of the normal force greatly affect the machining accuracy of the machine tool. The formation mechanism and weakening method of normal force fluctuation with core PMLSM are systematically studied. The main contents are as follows:
The relationship between the force fluctuation of the PMLSM method and the various harmonics of the magnetic field and the correlation between the normal force and the thrust are studied. On the basis of the analysis of the magnetic EMF harmonics, the armature reaction magnetomotive force harmonic and the air gap magnetic conductance harmonic, the analysis of the unbounded PMLSM force fluctuation of the initial end teeth is derived by the Maxwell Stress Tensor method and the integral method. From the angle of energy storage in the air gap magnetic field, the correlation between the direction force and the tangential electromagnetic thrust is analyzed from the angle of the air gap magnetic field, and the influence of the method of weakening the cogging effect, the end effect and the normal force fluctuation caused by the load disturbance on the tangential electromagnetic thrust is considered.
The influence of the motor parameters on the normal force fluctuation is studied. The width of the tooth top and the polar arc coefficient have a direct relationship with the normal force fluctuation. First, the influence of the tooth top width and the polar arc coefficient on the amplitude and the frequency of the normal force fluctuation caused by the cogging effect is analyzed. Then the finite element method is used to verify the difference. The fluctuation of the groove normal force and the influence on the thrust performance under the tooth top width and the different polar arc coefficient provide theoretical guidance for the optimal design of high performance linear motor.
In this paper, the method of weakening the normal force fluctuation of the three segments of the permanent magnetic pole is studied. First, the law of weakening the normal force fluctuation of the motor primary tooth top opening auxiliary slot and the unequal pole arc coefficient to weaken the force fluctuation is analyzed, and then the limitations of the two methods are analyzed. On this basis, the principle of the phase inverse phase counteraction is put forward. The three phase dislocation method of magnetic magnetic pole weakens or even counteracts the main subharmonic cogging force fluctuation, and avoids the horizontal pitching motion of the motor, and the effectiveness of the method is verified by the finite element method.
The phase current compensation control strategy is studied to weaken the normal force fluctuation caused by the end effect. The end normal force fluctuation is the main component of the normal force fluctuation. According to the special distribution rules of the three-phase winding of the permanent magnet linear servo motor of the fractional slot winding, the phase separation power to restrain the normal force fluctuation at the end part is proposed. The flow compensation control strategy follows the principle of the optimal thrust performance and the minimum normal force fluctuation in phase separation current compensation control. Then, the compensation model modeling method of the end normal force fluctuation is studied. Finally, the effectiveness of the compensation control strategy is verified by the joint simulation of Ansoft series software Simplorer and Maxwell.
The correctness of the theory and method of the permanent magnet linear servo motor prototype and the normal force test system is designed. The steady state measurement of the normal force of the 12 slot 8 pole whole magnetic pole and the three segment magnetic pole PMLSM of the primary end tooth is carried out, and the validity of the three segment dislocation method of the magnetic pole to weaken the fluctuation of the cogging method force is verified. The 12 slot 11 pole PMLSM is tested to verify the feasibility and effectiveness of the split phase current compensation control strategy to weaken the normal force fluctuation of the end.
【学位授予单位】：沈阳工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM383.4

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