永磁同步电机系统转矩脉动抑制的研究

发布时间：2018-11-04 16:02

【摘要】：永磁同步电机作为在高精度伺服场合的主要执行元件得到了越来越广泛的应用。但传统永磁同步电机控制系统中电机存在齿槽转矩、反电势含有谐波成分以及逆变器中功率器件的非线性等问题导致伺服电机系统产生了转矩脉动,影响了控制系统的控制性能。本文针对永磁同步电机系统转矩脉动影响因素进行分析,通过电机结构设计优化和转矩脉动抑制控制策略以及死区补偿控制方法的研究,以达到降低转矩脉动的目的。论文主要研究内容如下:针对国内外永磁同步电机系统转矩脉动抑制技术的研究现状进行综述,分析各类抑制永磁同步电机转矩脉动的结构优化方法以及控制策略,总结归纳各优化方法以及控制策略的优缺点。通过理论推导对永磁同步电机转矩脉动影响因素进行分析,探讨定转子结构、永磁体、隔磁桥、极槽配合等结构参数对电机转矩脉动影响,研究反电势和气隙磁密谐波以及齿槽转矩对电机输出转矩的影响。采用有限元仿真对转子偏心距、永磁体参数进行设计优化从而降低反电势和气隙磁密谐波,并在此基础上提出一种基于新型辅助隔磁桥的电机优化设计方法,从而进一步优化磁路,增强对电机转矩脉动的抑制效果。针对死区电压偏差引起电流畸变从而导致电机转矩脉动增大的问题,分析死区时间对相电压和相电流的影响,得到在功率器件开通关断时间以及管压降固定的前提下死区扰动电压的变化规律。研究一种基于判定中值电压相的电流方向与三相参考输出电压的直接补偿法补偿死区偏差,从而抑制电机在稳定运行状态下的电流谐波和转矩脉动,并对该方法进行系统建模与仿真。为解决逆变电路中功率器件电流变化导致器件的开通关断时间以及管压降变化的问题,建立死区扰动电压在静止和旋转坐标系中的电压矢量模型,利用扰动电压矢量幅值变化趋势相对稳定的特征,采用一种死区电压观测器对逆变器的死区电压进行实时辨识,以精确补偿死区电压。为提高电流环的鲁棒性,提出一种基于死区电压观测器与MRAC联合的控制策略对电流环扰动及转矩脉动进行抑制。最后,基于DSP控制芯片研制永磁同步电机转矩脉动抑制控制器,制定测试方案,搭建测试平台。针对样机的磁链以及直交轴电感进行测量,并进行基于MRAC的控制策略实验与基于死区观测器与MRAC联合的补偿控制策略实验。验证MRAC以及死区观测器控制策略的转矩脉动抑制和扰动补偿效果。
[Abstract]:Permanent magnet synchronous motor (PMSM) is widely used as the main actuator in high precision servo field. However, in the traditional PMSM control system, the torque ripple of the servo motor system is caused by the torque ripple of the servo motor system, which includes the harmonic component in the back EMF and the nonlinearity of the power device in the inverter. The control performance of the control system is affected. In this paper, the influence factors of torque ripple in permanent magnet synchronous motor system are analyzed, and the torque ripple reduction control strategy and dead-time compensation control method are studied to reduce torque ripple through the optimization of motor structure design and the research of torque ripple suppression control strategy. The main contents of this paper are as follows: according to the research status of torque ripple suppression technology in PMSM system at home and abroad, the structure optimization method and control strategy of PMSM torque ripple suppression are analyzed. The advantages and disadvantages of various optimization methods and control strategies are summarized. The influence factors of torque ripple of permanent magnet synchronous motor (PMSM) are analyzed by theoretical derivation, and the influence of structure parameters such as stator and rotor structure, permanent magnet, magnet isolation bridge and pole slot matching on torque ripple is discussed. The effects of reverse EMF, air-gap magnetic density harmonics and grooving torque on the output torque of the motor are studied. The rotor eccentricity and permanent magnet parameters are designed and optimized by finite element simulation to reduce the back EMF and air-gap magnetic density harmonics. On this basis, an optimal design method of the motor based on the new auxiliary magnetic isolation bridge is proposed. Thus, the magnetic circuit is further optimized and the torque ripple suppression effect is enhanced. In order to solve the problem that the current distortion caused by dead-time voltage deviation leads to the increase of torque ripple of motor, the influence of dead-time on phase voltage and phase current is analyzed. The variation of dead-zone disturbance voltage is obtained under the condition of turn-on time and fixed voltage drop of the power device. A direct compensation method based on the determination of the direction of the median voltage phase and the three-phase reference output voltage is proposed to compensate the dead-time deviation, which can suppress the current harmonics and torque ripple of the motor in stable operation. The method is modeled and simulated. In order to solve the problem of switching off time and voltage drop of power device due to the change of power device current in inverter circuit, a voltage vector model of dead-zone disturbance voltage in stationary and rotating coordinate system is established. A dead-time voltage observer is used to identify the dead-time voltage of the inverter in order to accurately compensate the dead-time voltage by using the characteristic that the amplitude of the disturbance voltage vector is relatively stable. In order to improve the robustness of the current loop, a control strategy based on dead-time voltage observer and MRAC is proposed to suppress the disturbance and torque ripple of the current loop. Finally, the torque ripple suppression controller of PMSM is developed based on DSP control chip. The flux chain and direct-axis inductance of the prototype are measured, and the control strategy experiment based on MRAC and compensation strategy experiment based on dead-time observer and MRAC is carried out. The torque ripple suppression and disturbance compensation effect of MRAC and dead-time observer control strategy are verified.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM341

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