基于谐波电流注入法的永磁同步电机转矩脉动抑制策略

发布时间：2018-08-06 11:08

【摘要】：永磁同步电机由于具有高效率、高转矩密度等优点而被广泛应用于各种要求高性能伺服控制的场合，比如数控机床、机器人控制等。这些高性能驱动场合对电机的输出转矩平滑度要求都很高。然而由于电机结构设计的非理想和逆变器的非线性特性，永磁同步电机的转矩存在较大的脉动，从而限制了永磁同步电机在高精度场合的应用。所以研究永磁同步电机的转矩脉动抑制策略，增加转矩平滑度，具有重大的工程意义。在不对电机本体设计进行优化的前提下，主要研究采用谐波电流注入法抑制表贴式永磁同步电机转矩脉动的控制策略。在分析永磁同步电机系统结构和工作原理的基础上，建立了永磁同步电机的基波数学模型。为了研究功率逆变器的非线性特性对电机转矩输出的影响，推导出了逆变器输出误差电压的傅里叶方程。针对永磁同步电机转子永磁磁链的畸变特点，对永磁同步电机在旋转坐标系下的谐波数学模型进行了研究，获得了谐波转矩的表达式。结合永磁同步电机齿槽转矩的产生机理，建立了齿槽转矩与电机本体参数的关系模型。基于谐波电流注入法的转矩脉动抑制策略是通过注入谐波电流，，实现对永磁同步电机转矩脉动的抑制。为了获得谐波参考电流指令，根据谐波转矩方程和对永磁体磁链的谐波分析，提出了计算q轴谐波电流指令的方法。在同步旋转坐标系下加入谐波电流闭环控制，使实际电流跟踪电流指令，产生的电磁转矩抵消电机的转矩脉动。在计算出交轴指令电流的基础上，提出了采用同步旋转PI控制器和比例谐振控制器的谐波电流注入策略，抑制电机的转矩脉动。针对电流环控制带宽有限的问题，在旋转坐标系下，提出用旋转PI控制器法实现对5次和7次谐波电流的提取和控制。为了减小控制系统的计算量，通过传统的PI控制器和比例谐振控制器的并联控制，使实际电流跟踪指令电流，实现对转矩谐波的抑制。在MATLAB/Simulink和SimplorerMaxwell下分别建立永磁同步电机控制系统的仿真模型，对转矩脉动抑制策略进行仿真分析。针对电机磁路非线性的问题，提出了有限元迭代计算的优化策略，仿真结果验证了算法的有效性。在仿真分析的基础上，设计了基于DSP的永磁同步电机硬件实验平台，并在硬件平台上进行转矩脉动抑制算法的实验验证。对比实验结果证明了两种谐波抑制策略都可以对永磁同步电机转矩脉动进行有效抑制，从而验证了算法的可行性。
[Abstract]:Permanent magnet synchronous motor (PMSM) has been widely used in various situations requiring high performance servo control, such as CNC machine tool, robot control and so on because of its high efficiency and high torque density. In these high performance driving situations, the output torque smoothness of the motor is very high. However, due to the non-ideal design of the motor structure and the nonlinear characteristics of the inverter, the torque of the permanent magnet synchronous motor has a large pulsation, which limits the application of the permanent magnet synchronous motor in high-precision situations. Therefore, it is of great engineering significance to study the torque ripple suppression strategy and increase the torque smoothness of PMSM. On the premise of not optimizing the design of motor body, the control strategy of restraining torque ripple of permanent magnet synchronous motor (PMSM) using harmonic current injection method is studied. On the basis of analyzing the system structure and working principle of permanent magnet synchronous motor (PMSM), the fundamental wave mathematical model of PMSM is established. In order to study the influence of the nonlinear characteristics of power inverter on the torque output of the motor, the Fourier equation of the output error voltage of the inverter is derived. According to the distortion characteristics of permanent magnet flux in permanent magnet synchronous motor rotor, the harmonic mathematical model of permanent magnet synchronous motor in rotating coordinate system is studied, and the expression of harmonic torque is obtained. Based on the generation mechanism of gear slot torque of permanent magnet synchronous motor (PMSM), the relationship model between tooth slot torque and motor body parameters is established. Torque ripple suppression strategy based on harmonic current injection is to suppress torque ripple of PMSM by injecting harmonic current. In order to obtain the harmonic reference current instruction, a method for calculating the Q axis harmonic current command is proposed according to the harmonic torque equation and the harmonic analysis of the flux chain of the permanent magnet. In the synchronous rotating coordinate system, the harmonic current closed-loop control is added to make the actual current track the current instruction, and the electromagnetic torque cancels the torque ripple of the motor. Based on the calculation of the alternating axis instruction current, a harmonic current injection strategy based on synchronous rotation Pi controller and proportional resonance controller is proposed to suppress the torque ripple of the motor. In order to solve the problem of limited current loop control bandwidth, a rotating Pi controller method is proposed to extract and control the fifth and seventh harmonic currents in the rotating coordinate system. In order to reduce the computational complexity of the control system, the actual current tracking instruction current is realized by parallel control of the traditional Pi controller and the proportional resonance controller, and the torque harmonic suppression is realized. The simulation model of PMSM control system is established under MATLAB/Simulink and SimplorerMaxwell, and the torque ripple suppression strategy is simulated and analyzed. In order to solve the nonlinear problem of motor magnetic circuit, the optimization strategy of finite element iterative calculation is proposed, and the simulation results verify the effectiveness of the algorithm. On the basis of simulation and analysis, the hardware experiment platform of permanent magnet synchronous motor based on DSP is designed, and the torque ripple suppression algorithm is verified by experiment on the hardware platform. The experimental results show that both harmonic suppression strategies can effectively suppress the torque ripple of PMSM, which verifies the feasibility of the algorithm.
【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】：2014
【分类号】：TM341

【共引文献】