New Decentralized Control Scheme for a Dynamic Voltage Restorer Based on the Elliptical Trajectory Compensation

In this paper, a novel decentralized control for a dynamic voltage restorer is proposed to deal with its captivity by improving the voltage quality of loads. The proposed technique controls the magnitude and the phase angle of the injected voltage to accomplish low-voltage ride-through based on the instantaneous calculations of voltages and currents and the application of elliptical compensation properly demonstrated at first. A set of generalized equations based on symmetric-sequence components are represented, aiming to separately control active and reactive powers with two individually adaptable parameters. Moreover, this approach can also describe a theoretical methodology by regulating the status parameters so that the multiple alternatives can be provided. The two parameters are an external voltage contribution of this work utilized to raise and equalize the phase voltage for a particular purpose of positive- and negative-sequence injected powers. Furthermore, a control algorithm for reference generators that provide flexible voltage support is proposed simultaneously to improve ride-through ability. Results of the simulation in the MATLAB indicate that the proposed control strategies can compensate voltage sags in a considerable short-time period. Finally, the laboratory test is performed to verify the effectiveness of the proposed approach that preserves flexible controllability.