Design and Implementation of a State Feedback Controller for the Series Voltage Sag Compensator

• Main Authors: Jhao-Ming Chen, 陳召明
• Other Authors: Po-Tai Cheng
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/88643664427099692156

碩士 === 國立清華大學 === 電機工程學系 === 95 === Survey results suggest that 92% of the break at industrial equipment is voltage sag related. When voltage sag happens, the shuts down of situation in factories will result in substantial economic loss. To build a high quality of power supply, the voltage sag compensator is applied. The compensator based on transformer-coupled series-connected voltage source inverter, is among the most cost-effective solution to protect sensitive loads. In previous studies, closed loop controllers are used to improve active damping and to get better stability of system. These common controllers operate directly in the time domain or in stationary frame. Without transform into the synchronous frame, the controllers have less robustness and less accuracy. This thesis proposes a state feedback controller has very high disturbance rejection capability to improve the performance of the voltage sag compensator. The load transformers which protects the plant operation and staff’s safety are usually series connected to sensitive equipments for isolating the power supply. When voltage fault happened, a DC offset will occur in the flux linkage of load transformer. The core saturates at the voltage restored and then the inrush current happened. As a result, voltage sag compensator will suffer from the significant the inrush current. The flux offset compensation mechanism is also proposed to mitigate the inrush current of the load transformer. This thesis proposed better performance controller and flux offset compensator. The operation principles and the disturbance rejection capability of the controller are presented in detail. Simulations and experimental results validate the proposed approach.