Research On Economic Dynamic Voltage Restorer

With the development of science and technology, the power quality has been occupied an important position in power system as a part of evaluating power system. In the electricity networks, the power quality problems mainly include voltage surge, voltage drop and instantaneous voltage interruption. The most probability of power quality problems is voltage drop. Dynamic voltage restorer, as a new type of power quality control device, has been widely adopted in the actual production and usual life because of its good protection effect to the load device in the case of voltage drop.In this paper, the working principle and the system structure of DVR are systematically researched. The DC side of DVR has enough energy to support is the key to export stable compensation voltage. Through the analysis and comparison of DC side energy access of DVR, it puts forward an economic DVR structure based on the classical DVR. The economic DVR Structure simplifies the energy storage link of the classical DVR. The structure uses an uncontrolled rectifier circuit and a boost and gets energy from the residual voltage of the grid, and it uses boost circuit to stabilize voltage. Setting the expectation DC voltage value as the goal and designing the boost circuit for double closed-loop control through PI controller, it can makes the structure export stable voltage during the voltage sag so that the stable DC side voltage of DVR ensures it to export enough compensation voltage.On Matlab/Simulink platform, the paper simulates the economic DVR. The result shows that the voltage of DC side can be well maintained under the control of the rectifier circuit and boost circuit, DVR can inject enough compensation voltage to maintain the stability of the load voltage during the voltage sag. On the basis of the simulation of economic DVR, the paper uses the TMS3202812chip to set up a physics experiment platform and designs the main circuit and control circuit of the economical DVR. The paper conducts an experiment of the physical model of economic DVR. The experimental result identifies the correctness and feasibility of the economic DVR.