High Performance Dynamic Voltage Restorer with Harmonic Compensation Capability

Voltage sags are a common issue in power systems and can cause severe damage to sensitive electronic equipment. The paper proposes an innovative power quality improvement method for the Dynamic Voltage Restorers (DVR) system, employing two DVRs of varying capacities to effectively counteract voltage variations in the grid. In this configuration, the first DVR is responsible for providing high-power compensation with a large DC-link capacitor to address significant voltage fluctuations in the grid. Its core objective is to maintain a stable and reliable power supply, especially during pronounced voltage fluctuations. The second DVR is designed with greater precision, with its main role being fine-tuning, that is, compensating for the minor discrepancies between the standard 220V voltage and the actual output voltage. This inverter has a lower power output and a smaller DC-link capacitor, allowing for more accurate voltage adjustments, thereby further reducing voltage errors and enhancing the overall power quality. Experimental results indicate that this method can accurately detect voltage sags, offering high precision and reliability.