感应电机高速运行控制的关键技术研究

发布时间：2018-06-29 22:39

本文选题：电压和电流限制 + 最大转矩弱磁控制　；参考：《上海大学》2014年硕士论文

【摘要】：随着交流传动系统的发展和广泛应用，对系统调速范围、稳态精度、动态响应有着越来越高的要求，具有弱磁升速性能的调速系统普遍应用于电力机车、电动汽车和数控机床主轴驱动等领域。作为交流电机高性能控制的典型代表，基于磁链定向的矢量控制由于实现了定子电流励磁分量和转矩分量的解耦，在磁链的控制上有着独特的优势和便利，成为研究电机高速运行的主要方案之一。本文针对感应电机高速控制下的关键技术做了系统的分析，在矢量控制的基础上对系统的弱磁控制、逆变器PWM调制技术和电流调节器设计这几个方面做了深入研究，主要内容如下：以弱磁控制为基础的感应电机高速运行必然会导致输出转矩的衰减以及系统动态性能的降低。本文深入分析了感应电机在电压和电流限制条下全速度范围内的最大转矩工作点轨迹，进而给出对应的最大转矩弱磁控制。该弱磁方法原理清晰，设计简单，通过电机参考电压的反馈，能够在全范围内实现对励磁电流的优化调节，且不受电机参数影响。仿真结果表明该弱磁控制运行稳定，具有很好的动态调节效果，能保证电机在全速度范围内以最大转矩运行。以电压源型PWM逆变器作为驱动装置的传动系统具有快速的动态响应，逆变器采用空间矢量PWM的控制方式虽然输出电流谐波含量小，但仍无法完全利用母线电压。本文基于基波相电压等效的原理，着重分析了逆变器在过调制区域输出电压矢量的轨迹，通过对轨迹的控制能够使逆变器过渡到六阶梯波模式运行，输出电压达到最大。将过调制技术和弱磁控制相结合，可以增大电压限制边界，进一步提高电机高速运行时的输出转矩。此外，当矢量控制系统运行在高速时，电机dq轴电压耦合的加剧以及数字系统的控制延迟会导致电流调节器性能的恶化，影响系统运行的稳定性。本文建立了感应电机离散域数学模型，对不同电流调节器的性能做了分析和对比，并基于离散域内零极点对消的方法，提出了一种新的电流调节器设计，能够在全速范围内实现dq轴电压的解耦并对系统控制延迟进行补偿，提高了对高频信号的调节能力。仿真和实验结果表明这种电流调节器具有宽速范围内的稳定性，能够改善系统的控制精度和稳态性能。最后，本文建立了能量互馈型双感应电机对拖系统的仿真模型，系统采用基于全阶磁链观测器的直接磁链定向控制，通过对联轴器的建模，实现了电机之间的力矩传递，很好地模拟了实际中的刚性联接，仿真结果与实验相对比，体现出良好参照性。
[Abstract]:With the development and wide application of AC drive system, the speed regulation range, steady-state precision and dynamic response of the system have higher and higher requirements. The speed regulating system with weak magnetic field raising speed performance is widely used in electric locomotives. Electric vehicles and CNC machine tool spindle drive and other areas. As a typical example of high performance control of AC motor, vector control based on flux direction has unique advantages and convenience in flux control because of decoupling stator current excitation component and torque component. It has become one of the main schemes to study the motor running at high speed. In this paper, the key technology of high speed control of induction motor is systematically analyzed. Based on vector control, the weak magnetic field control of the system, PWM modulation technology of inverter and the design of current regulator are deeply studied. The main contents are as follows: the high speed operation of induction motor based on weak magnetic field control will inevitably lead to the attenuation of the output torque and the degradation of the dynamic performance of the system. In this paper, the maximum torque working point locus of induction motor in the full speed range of voltage and current limiting bar is analyzed, and the corresponding maximum torque weak magnetic control is given. The principle of the method is clear and the design is simple. Through the feedback of the reference voltage of the motor, the excitation current can be optimized and adjusted in the whole range without the influence of the motor parameters. The simulation results show that the weak magnetic field control is stable and has a good dynamic regulation effect. It can guarantee the motor running with the maximum torque in the range of full speed. The drive system with the voltage source PWM inverter as the driving device has fast dynamic response. Although the output current harmonic content of the inverter is small, the bus voltage can not be fully utilized in the control mode of the inverter using space vector PWM. Based on the principle of equivalent fundamental phase voltage, this paper focuses on the analysis of the output voltage vector trajectory of the inverter in the over-modulated region. By controlling the trajectory, the inverter can be transferred to the six-step wave mode and the output voltage reaches the maximum. By combining overmodulation with weak magnetic field control, the voltage limiting boundary can be increased, and the output torque of motor at high speed can be further improved. In addition, when the vector control system is running at high speed, the acceleration of the voltage coupling of the motor's dq axis and the control delay of the digital system will lead to the deterioration of the performance of the current regulator, which will affect the stability of the system. In this paper, the discrete domain mathematical model of induction motor is established, and the performance of different current regulators is analyzed and compared. Based on the method of zero pole cancellation in discrete domain, a new design of current regulator is proposed. It can decouple the dq-axis voltage and compensate the system control delay in the full speed range, which improves the adjusting ability of the high-frequency signal. The simulation and experimental results show that the current regulator is stable in a wide speed range and can improve the control accuracy and steady-state performance of the system. Finally, the simulation model of the dual induction motor pair towing system with mutual energy feedback is established. The direct flux linkage directional control based on the full order flux observer is adopted in the system. By modeling the coupling, the torque transfer between the motors is realized. The rigid connection in practice is well simulated, and the simulation results are compared with the experiment, showing good reference.
【学位授予单位】：上海大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM346

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