Optimized Control Strategy for a Medium-Voltage DVR

Voltage sags are a major problem in present distribution systems. Therefore, different solutions are examined to compensate these sags and to avoid production losses at sensitive loads. Especially, dynamic voltage restorers (DVR) are one solution to realize this goal. Presently, a system wide integration of DVRs is hampered because of costs. Voltage sag compensation requires energy storage, the amount of which depends greatly on the required voltage level (V_DVR). Present control strategies are either able to minimize the needed voltage, to allow a better utilization of the storage system or to minimize the distortions at the load. To avoid this drawback an optimized control strategy is presented in this paper, which is able to reduce the voltage amplitude and causes low distortions at the load side. In the following paper, a brief introduction of the basic DVR principle is given. After this, different control strategies are briefly described, before an optimized strategy is presented. Finally, simulation results are shown to verify and prove the functionality of the presented control strategy