Electricity is clean and efficient energy that is essential for human life and widely used. As the power demand increases, the demand for power quality is constantly increasing. The sudden voltage fluctuations in industrial production hinder the normal operation of automation devices and even cause damage to products.
In the evaluation of power quality, system frequency and voltage at the grid nodes are main indices, and the voltage, symmetry and waveform of three-phase network are auxiliary indices.
The dynamic voltage restorer (DVR) is a power electronic device used to protect the load from the shock caused by voltage fluctuations occurring in the electrical network. This device is very effective in improving power quality, compared to conventional compensating devices.
Aiming to compensate harmonics and unbalances, Jong Il Bok, a researcher at the Faculty of Electrical Engineering, has proposed a controller for standard voltage calculation of DVR and a current controller using PCI method. Then, he has verified the accuracy of a designed controller in MATLAB/Simulink environment.
The simulation results show that the dynamic voltage restorer can cope with sudden voltage fluctuations and effectively prevent factors affecting power quality such as voltage fluctuations.
And the proposed current controller can be used not only for DVR but also for AC sequences control.