Control of Dynamic Voltage Restorer Under Voltage Sag and Nonlinear Load

  • Minh Nhut Ho Faculty of Electronics Engineering 2, Posts and Telecommunications Institute of Technology in Ho Chi Minh City
  • Luong Tan Van
  • Huan Trong Nguyen
Keywords: Dynamic voltage restorer, nonlinear load, sliding mode control, voltage sags


In this paper, a nonlinear control scheme for dynamic voltage restorer (DVR) is proposed to reduce the voltage disturbances for loads under grid voltage sags and nonlinear loads. First, the nonlinear model of the system consisting of LC filter is obtained in the dq0 synchronous reference frame. Then, the controller design is performed by using the sliding mode control, where the load voltages are kept almost sinusoidal by controlling the dq0 axis components of the DVR output voltages. With this scheme, the power quality is significantly improved, compared with the conventional proportional-integral (PI) controller under grid voltage sags and nonlinear loads. Simulation studies are performed to verify the validity of the proposed method.