Slip Frequency Controlled Type of Sensorless Vector Control of Induction Motor Using Flux Observer

无速度传感器矢量控制因其与恒V/f控制相比具有更高的速度控制性能而受到人们的关注。本文提出了一种基于磁链观测器的无传感器矢量控制系统，并利用DSP控制的IGBT逆变器实现了该系统。为了在各种工况下实现良好的稳态和暂态性能，对PWM逆变器的控制器设计进行了研究，开发了一种精确的电压控制方法。本工作取得的主要成果如下：1。实验系统：采用数字信号处理器TMS320C30实现控制系统。已经开发了两种软件。一个是用DSP汇编语言编写的基于观测器的无传感器矢量控制程序，另一个是用C语言编写的监测程序。通过补偿IGBT的电压降和死区时间，实现了PWM逆变器的精确电压控制。计算结果与实验结果：所提方法的稳态和暂态计算结果与计算结果吻合较好。因此，基于所提出的分析模型进行了系统设计。稳定性改进：我们提出了一种无传感器的方法，该方法在电压计算中省去了漏感。结果表明，我们的方法比传统的方法更稳定。参数辨识：通过在磁化电流中加入交流分量，确定定子电阻和转子电阻。采用该方法，鲁棒性得到了令人满意的提高。另一种无传感器矢量控制：提出了一种基于定子电阻识别的q轴磁链无传感器矢量控制方法，并进行了实验验证。提出了一种基于无功功率的无传感器矢量控制方法。在这种方法中，定子电阻是不必要的。

The speed sensorless vector control has attracted the attention because of high performance speed control of an induction motor comparing with the constant V/f control. In this research, new flux observer based sensorless vector control systems are proposed and implemented by using DSP controlled IGBT inverter. In order to realize excellent steady-state and transient performances for various operating conditions, the design of controller is studied and an accurate voltage control of PWM inverter is developed.Principal results obtained by this work are as follows ;1. Experimental system : The digital signal processor (TMS320C30) is used for the implementation of the control system. Two kinds of softwares have been developed. One is an observer based sensorless vector control program written in the DSP assembly language and the other is a monitoring program written in C language. By compensating the voltage drop and dead time of IGBT,an accurate voltage control of PWM inverter was developed.2. Computed and experimental results : The experimental results of proposed method show good agreement with the computed ones concerning with the steady state and transient condition. Therefore, the system design which is based on the proposed analytical model is attained.3. Stability improvement : We proposed a sensorless method in which the leakage inductance was omitted in the voltage computation. As the result, our method is more stable than the conventional one.4. Parameter identification : By adding an altanative component in the magnetizing current, both the stator resistance and the rotor one were identified. By using this method, the robustness will be improved satisfactory.5. Another sensorless vector control : A sensorless vector control using q-axis flux with stator resistance identification was proposed and tested experimentally. And a sensorless vector control using a reactive power was proposed too. In this method, the stator resistance is not necessary.