| Voltage sag had become a remarkable problem in power quality, along with the development of technology in modern times and the extensive application of various sensitivity electro-equipments. Dynamic Voltage Restorer (DVR) is an important member of Custom Power family. Its fine dynamic function make it the most effective and economic device to compensate the voltage sag. DVR pours the standard and the system voltage's difference value into the system to compensate the distortion, it can balance swells or sags which cause dynamic voltage quality question, also can balance non-balance of three-phase or harmonics which cause quiescent voltage quality question, is one of the present research hot spots in power quality installment.For the better effective compensation to voltage sag, the first research is the detection method of voltage; the other work has to focus on control method of DVR.The dissertation aims to have a primary probe into questions mentioned above. Firstly, introduced DVR's compositions of each part, and also produced the DVR's topology which composed by three single-phase full-bridge inverter. A detailed analysis of the present detection method to voltage sag is presented, finally used the improved single-phase voltage dq detection method. Expatiated on the principle of SPWM typed DVR compensating voltage sag amply then. Choose the use feed-forward control and add the reaction control to the mixture control in the control strategy, to solve the damp weak and stable value could not achieve the request and cannot adapt the variation of load transformation in feed-forward control.Then the designed project is simulated in SIMULINK environment of MATLAB software, built the simulation model for examination algorithm and the control strategy. The improved single-phase voltage dq detection method is tested, the results show this method is accuracy and minimal delay. The results of the simulation has proved that the designed DVR is accurate and applicability. |
