Research On SVM-DTC AC Variable Frequency Speed Regulation Experimental Platform Based On Sliding Mode Observer

AC variable frequency speed regulation technology has played an important role in many fields, such as industrial production, aerospace, rail transportation and daily life. In direct torque control, the value of stator flux observation will directly influence the calculation of electromagnetic torque and the performance of the control system. The traditional u-i observation model is influenced by the use of pure integrator and the effect of stator resistance. Under the background of motion control system course and experimental teaching in universities, in order to achieve accurate observation of stator flux and speed sensorless technology, the proposed experimental platform of SVM-DTC control based on sliding mode observer for AC variable frequency speed regulation is designed in this paper.Firstly, the principle of direct torque control based on space vector pulse width modulation is analyzed on the basis of the dynamic mathematical model of asynchronous motor, and the space vector pulse width modulation technology is discussed. Focuses on the analysis of the problems arisen in the traditional stator flux u-i observation model due to the use of pure integrator and the influence of the stator resistance, then the simulation analysis and verification are carried on.The stator flux observation model based on sliding mode observer is researched. Taking the stator current and stator flux in the synchronous rotating reference frame as state variables to establish the state observer, then the sliding mode observer is built. And through the feedback matrix to form a closed loop system t o correct the value of stator flux linkage and to improve the accuracy of the stator flux observer. On the basis of this, a speed identification method based on model reference adaptive system is studied, and the adaptive law of speed identification is designed under the condition of ensuring the stability of the system. The SVM-DTC control system model based on the sliding mode observer is constructed in Matlab/Simulink software, and the feasibility of the control algorithm and the performance of the control system are verified by the simulation experiment.The hardware of the AC variable frequency speed regulation experimental platform is designed, including the main circuit, control circuit and protection circuit. Among them, the intelligent power module(IPM) is aimed to reduce the complexity of the inverter circuit. To achieve the openness, and the strong operability requirements of the experimental platform, PCI bus technology of the PC is adopted to realize data exchanging between it and the control chip DSP2812.Finally, the human-computer interactive system and the software of the control algorithm are designed in the C++ Visual environment, and the control system is tested on the experimental platform. The experimental results show that the SVMDTC control system based on sliding mode observer has high precision and strong robustness for stator flux observation, and the speed can be identified effectively. The AC variable frequency speed regulation experimental platform has both good dynamic and static performance.