LAUSR

Abstract: For shielding voltage sensitive loads from diverse power quality problems (Voltage harmonic distortion and voltage sag/swell) a wide variety of custom power devices are used. Dynamic voltage restorer (DVR) is one of the important custom power device presently used for mitigation of above mentioned power quality problems. In this paper, reduced-rule fuzzy logic controller based on synchronous reference frame theory for controlling of self-supported dynamic voltage restorer (DVR) is proposed. As a result of the proposed controller, the mathematical model of plant is not at all needed and the control signals required by the DVR are thoroughly provided during various types of power quality problems at the source side. The performance of this technique is better than the other existing techniques and it is very simple to implement, less complex, very flexible and robust in nature. For the same system parameters, the fuzzy logic based controller uses the less amount of reactive power to mitigate the various disturbances at source side compared to PI based controller, which results into reduced rating of IGBTs and consequently leading to lowering of the overall cost. DVR is simulated for mitigation of various power quality problems (voltage harmonic distortion, balanced voltage sag/swell, unbalanced voltage sag/swell, balanced voltage sag/swell with harmonic distortion and unbalanced voltage sag/swell with harmonic distortion) and the simulation results verified by experimental results are presented displaying the workability of proposed controller.