摘 要
异步电动机的动态数学模型是一个高阶、非线性，强耦合的多变量系统。采用坐标变换的方式将三相静止坐标系变为两相同步旋转坐标系，可以实现定子电流的解耦，从而实现磁通和转矩的解耦控制，达到直流电机的控制效果。按转子磁链定向使交流调速系统的性能产生了质的飞跃。无速度传感器控制解决问题的出发点是利用检测的定子电压、电流等容易检测到的物理量进行速度估计以取代速度传感器。这样既减少了成本，又提高了控制系统的简易性和鲁棒性。
无速度传感器的矢量控制重点是磁链的观测和转速的估计。由于电机在运行过程中的参数会发生变化，必须保证磁链和转速估计的准确性，使系统具有良好的动态性能。本文应用基于超稳定性理论的模型参考自适应系统，对无速度传感器的矢量控制进行转速估计和磁链观测。对系统的仿真结果表明，基于模型参考自适应的矢量控制系统具有良好的静态和动态性能。
关键词：异步电机；无速度传感器的矢量控制；模型参考自适应；转速估计；磁链观测
ABSTRACT
Dynamic mathematical model of asynchronous motor is a higher order、nonlinear、the strong coupling of multivariable system. Using coordinate transformation to change the three-phase stationary coordinate system into a two-phase synchronous rotating coordinate system, You can implement a decoupling of the stator current , to realize the decoupling control of flux and torque ,so as to achieve the effect of DC motor controls.the rotor field oriented control has brought essential advances in AC variable speed drive system. the starting point to solve the problem of sensorless control is to use detection of stator voltage and current easily detected physical quantities to replace the speed sensor . In this way, reducing costs, improving the control system simplicity and robustness.
The key of speed sensorless vector control is flux and speed estimation . Because the varies of parameter when the motor running, must ensure that flux and speed estimation accuracy, make the system has good dynamic performance.the speed estimation and rotor flux observation methods are studied using the theory of Model Reference Adaptive System for the speed sensorless vector control system in the article.the simulation results show the MRAS-based field oriented control system has good static and dynamic performance.
Keywords:asynchronous motor；Sensorless vector control；MRAS；Speed estimation；Flux observer
目 录
1 绪论 ................................................................................................................................................. 1
1.1 引言 ...................................................................................................................................... 1 1.2 电力电子器件和微处理器的发展 ...................................................................................... 1 1.3 无速度传感器矢量控制的研究现状 .................................................................................. 3
1.3.1 直接计算法 ............................................................................................................... 4 1.3.2 模型参考自适应法（MRAS) .................................................................................. 4 1.3.3 基于扩展卡尔曼滤波的状态估计算法 ................................................................... 5 1.3.4 神经网络法 ............................................................................................................... 5 1.4 课题研究的主要内容和结构安排 ...................................................................................... 5 2 异步电机的矢量控制理论 ............................................................................................................. 7
2.1 异步电机的数学模型 .......................................................................................................... 7
2.1.1 异步电机在三相静止坐标系下的数学模型 ........................................................... 8 2.1.2 坐标变换及变换矩阵 ............................................................................................. 10 2.1.3 异步电机在两相坐标系下的数学模型 ................................................................. 12 2.1.4 异步电机在两相同步旋转坐标系的数学模型 ..................................................... 13 2.2 异步电机矢量控制 ............................................................................................................ 13
2.2.1 矢量控制的原理 ..................................................................................................... 14 2.2.2 转子磁场定向矢量控制原理及结构 ..................................................................... 14
3 磁链观测和转速估计的方法研究 ............................................................................................... 18
3.1 磁链观测方法研究 ............................................................................................................ 18
3.1.1 基于电压模型的方法 ............................................................................................. 18 3.1.2 基于电流模型的方法 ............................................................................................. 21 3.2 基于模型参考自适应的转速辨识 .................................................................................... 21
3.2.1 基于模型参考自适应系统设计的基本理论 ......................................................... 22 3.2.2 基于超稳定性和正实性系统的设计 ..................................................................... 22 3.2.3 基于转子磁链模型的转速辨识方法 ..................................................................... 24 3.3 基于改进模型参考自适应方法的无速度传感器研究 .................................................... 28
3.3.1 基于反电动势模型的速度辨识 ............................................................................. 28 3.3.2 基于瞬时无功功率模型的速度辨识 ..................................................................... 28 3.4 本章小结 ............................................................................................................................ 29 4 无速度传感器矢量控制系统仿真研究 ....................................................................................... 30
4.1 基于电流模型磁链估计的控制系统仿真 ........................................................................ 30
4.1.1 基于电流模型的无速度传感器矢量控制系统仿真电路图 ................................. 30 4.1.2 仿真模型子系统说明 ............................................................................................. 30 4.2 基于电压模型的无速度传感器矢量控制系统 ................................................................ 32 4.3 仿真结果分析 .................................................................................................................... 33 4.4 本章小结 ............................................................................................................................ 38 5 基于DSP的系统硬件 ............................................................................................................... 39 5.1 主电源电路的设计 ............................................................................................................ 39
5.1.1 整流电路部分 ......................................................................................................... 40 5.1.2 滤波电路部分 ......................................................................................................... 40 5.1.3 逆变电路部分 ......................................................................................................... 41
基于DSP的异步电机无速度传感器的矢量控制仿真
