Neural network controlled voltage disturbance detector and output voltage regulator for dynamic voltage restorer

This paper describes the high power DVR (Dynamic Voltage Restorer) with the neural network controlled voltage disturbance detector and output voltage regulator. Two essential parts of DVR control are how to detect the voltage disturbance such as voltage sag and how to compensate it as fast as possible respectively. The new voltage disturbance detector was implemented by using the delta rule of the neural network control. Through the proposed method, we can instantaneously track the amplitude of each phase voltage under the severe unbalanced voltage conditions. Compared to the conventional synchronous reference frame method, the proposed one shows the minimum time delay to determine the instance of the voltage disturbance event. Also a modified d-q transformed voltage regulator for single phase inverter was adopted to obtain the fast dynamic response and the robustness, where three independent single phase inverters are controlled by using the amplitude of source voltage obtained by neural network controller. By using the proposed voltage regulator, the voltage disturbance such as voltage sag can be compensated quickly to the nominal voltage level. The proposed disturbance detector and the voltage regulator were applied to the high power DVR (1000kVA@44OV) that was developed for the application of semiconductor manufacture plant. The performances of the proposed DVR control were verified through computer simulation and experimental results. Finally, conclusions are given.