A four leg voltage source converter based dynamic voltage restorer

In this paper, the closed-loop control of a 4-leg voltage source converter-based dynamic voltage restorer has been described. A low-voltage, laboratory model of the dynamic voltage restorer has been constructed. The controller functions have been implemented in a DSP-based digital controller. A program for resolving the 3-phase variables into the sequence components has also been included among the controller functions. The DVR is able to protect the load from voltage sags due to various types of faults.