Fast Dynamic Control Behavior of a Capacitor Supported Dynamic Voltage Restorer (DVR)

摘要

Dynamic voltage restorers (DVRs) are the most popular Devices in industry to reduce the undesirable effect of voltage sags/swells to sensitive loads. The DVR is a series connected device whose function is to maintain sensitive loads voltage within the permissible range. This work provides us to find the optimal location and the optimal DVR settings to enhance the distribution related loading issues. It is based on the boundary control method with the second-order switching surface. The load voltage can ideally be reverted to the steady state in tw o sw itching actions during a supply voltage dip. The outer loop is used to generate the DVR output reference for the inner loop. It has three control modes for achieving two different functions, including the output regulation and output restoration. The first mode is for regulating the capacitor voltage on the dc side of the inverter, so that the output of the DVR is regulated at the nominal voltage. Conventional voltage-restoration technique is based on injecting voltage being in-phase with the supply voltage. The injected voltage magnitude will be the minimum, but the energy injected by the DVR is no minimal. In order to minimize the required capacity of the dc source, a minimum energy injection concept is taken into the considerations. It is based on maximizing the active power delivered by the supply mains and the reactive power handled by the DVR during the sag and swell cases. The review model has been built and tested the dynamic behaviors of the mo del under different sagged a nd swelled conditions and depths w ill be investigated. The quality of the load voltage under unbalanced and distorted phase voltages, and nonlinear inductive load is analyzed