The Research Of Dynamic Voltage Restorer's Control

Along with the development of science and technology, the end-users ask for highly quality of power constantly. As well, the power-grid's pollution is growing. Dynamic voltage restorer (DVR) is the effective device for compensating voltage sag, swell, three-phase imbalance and harmonics. The paper research on DVR's theory and it's unit forms, on this basis, the paper focuses on the detection and control for the DVR.The paper analyzes of two main circuit of DVR, And adopts synchronous transformation of coordinates which can detect the fundamental-wave positive-sequence voltage quickly and determine the command voltage quickly and accurately. On the bases of analyzing the energy flow, the paper gave an energy optimized method which can ensure the minimum active loss. This method can make the best of the device, and have highly economic benefit.The paper adopts a hysteresis control method which can compensate voltage aberrance problems. The paper adopts a one-cycle control method which has high control accuracy, good dynamic track-ability and strong anti-jamming capability. Considering the internal resistance and the leakage reactance of the transformer, the paper gave three control strategies of feedforward control, feedback control and double-feed control strategy, and compared their relative merits by simulations.The paper designs the parameters of series transformer, three-phase converter, filter circuit, etc, and designs the elementary diagrams of voltage detecting circuit, light-coupled isolation circuit, power supply circuit, etc. Besides, the paper writes the main program and the interruption subroutine, sets up the hardware circuit and debugs some routine.