Research On Suppressing Reactive Power Oscillation Of SVG Based On Linear Active Disturbance Rejection Control

In this paper, a large number of reactive power consumption in the normal operation of injection molding machine, and the serious problem of voltage drop of common connection point is studied. The SVG device with excellent dynamic performance is designed to compensate the power consumption. A Linear Active Disturbance Rejection control strategy is presented for the reactive power oscillation caused by the response delay of the SVG device under large impact load. Which avoids the possible problem of reactive power oscillation, and the robustness of the device is greatly improved, to ensure the SVG device running stable. According to the actual working conditions, analyzed the principle of harmonic amplification of TSF device, made specific analysis of occurrence of resonance in the TSF device and the network side may inhibit. By using the designed SVG device to suppress the parallel resonance, the system can ensure the stability of the system in safe condition.By analyzing the principle of the SVG device, we can get the relationship of reactive power and voltage of the common connection point, and from the mathematic model of SVG, it is known that it has the characteristics of strong coupling. The whole disturbance coursed by coupling term of system and parameter perturbation can be measured through extend state observer of Linear Active Disturbance Rejection controller and can be compensated timely, so the complete decoupling control of d-q axis in SVG model is realized. By pole assignment and linearization method, the design of controller parameter is simplified. In addition, this paper also used Lyapunov stability analysis method to verify the stability of designed controller.The amplification mechanism of harmonic current in TSF is analyzed through mathematical modeling method. And the harmonic degree and its condition may occur in the harmonic current amplification were listed based the parameters of the actual compensation device of the injection molding machine system. To ensure the stability of the whole system, the presented SVG device was used as active damping to suppress the resonance may occur in the TSF and the network side. The Bode diagram analysis also shows that SVG has a good inhibitory effect on this resonance. It is indicated that the presented SVG device can maintain the stability of the system.Finally, the presented device is simulated and verified in Matlab/Simulink environment. The effects of Linear Active Disturbance Rejection controller and PI controller were compared in the condition of stable operation and being suddenly cut off of the motor, and thyristor rectifier DC motor was used as the load. The results shows that SVG device based Linear Active Disturbance Rejection controller can compensate reactive power and stabilize the voltage of common connected point more rapidly. When faced with the large impact load, it will not cause reactive power oscillation like PI controller. So it can maintain the stability of the system. Finally, the hardware experiment was carried out in the laboratory environment. The Linear Active Disturbance Rejection control algorithm was implemented in DSP, it is proved that the effectiveness of the proposed controlling strategy.