感应电机无速度传感器控制及非线性补偿研究

发布时间：2018-04-14 07:40

本文选题：矢量控制 + 感应电机　；参考：《河南科技大学》2017年硕士论文

【摘要】：人们对感应电机的需求日益增大,对感应电机的控制要求也日益严格。由于无速度传感器矢量控制系统在交流调速系统中具有优异的性能而成为感应电机常用的控制方法,它对定子电流进行解耦,达到良好的控制性能。但是在感应电机的运行过程中电流流动产生热量,影响转子电阻的阻值,对定子侧磁链的估算产生影响,导致转速估算的准确性较低,所以高精度的控制系统对定转子电阻的准确辨识依赖性较高,因此,对无速度传感器矢量控制系统的定转子电阻辨识是十分必要的。针对以上所提出的问题,本文采用全阶状态观测器自适应控制,为了加快收敛速度对反馈矩阵进行化简,实现了转子电阻及转速的辨识,消除了在感应电机转速辨识的过程中因为转子电阻值的改变而带来的精度问题。由于全阶状态观测器能够同时辨识转子电阻及转速,所以简化了辨识方式,节约了硬件的使用成本。另外,考虑到感应电机控制中成本及精度的原因,采用空间矢量脉冲宽度调制模块的输出电压代替定子电压,但为了防止逆变器桥臂直通而加入的死区时间,虽然时间很短暂,但是随着时间的推移会造成积累效应,特别是在电压源型逆变器低频和轻载时的死区效应使电机产生相电压和相电流畸变、转速和转矩脉动等问题,导致系统性能降低。为提高系统性能,对死区进行补偿。死区补偿首先通过计算控制周期内的误差时间,算出误差时间与电流的对应关系,最后将算出的周期内误差电压补偿到逆变器输入端上。通过补偿误差电压,降低了电流谐波对控制系统的影响,同时电网侧的能量利用率得到了提升。
[Abstract]:The demand for induction motor is increasing day by day, and the control requirement of induction motor is becoming more and more strict.Speed sensorless vector control system has become a common control method for induction motor because of its excellent performance in AC speed regulation system. It decouples stator current and achieves good control performance.However, the current flow produces heat during the operation of the induction motor, which affects the resistance of the rotor and the estimation of the stator side flux, which leads to the low accuracy of the speed estimation.Therefore, the accurate identification of stator and rotor resistance is highly dependent on the high precision control system, so it is very necessary to identify the stator and rotor resistance of speed sensorless vector control system.In order to speed up the convergence, the feedback matrix is simplified and the rotor resistance and speed are identified by using the full-order state observer adaptive control.The accuracy problem caused by the change of rotor resistance during the speed identification of induction motor is eliminated.Because the full order state observer can identify the rotor resistance and speed simultaneously, the identification method is simplified and the cost of hardware is saved.In addition, considering the cost and precision of the induction motor control, the output voltage of the space vector pulse width modulation module is used to replace the stator voltage, but in order to prevent the inverter leg from passing through, the dead time is very short.However, with the passage of time, the accumulation effect will be caused, especially the dead-time effect of voltage source inverter at low frequency and light load, which will lead to phase voltage and phase current distortion, speed and torque ripple and so on, resulting in the system performance decline.In order to improve the performance of the system, the dead zone is compensated.The relationship between the error time and the current is calculated by calculating the error time in the control cycle. Finally, the error voltage is compensated to the inverter input.By compensating the error voltage, the influence of current harmonics on the control system is reduced, and the energy utilization ratio of the power grid side is improved.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM346;TP273

【参考文献】