Dynamic Voltage Restorer (DVR) for Power Quality Enhancement

The implementation of a Dynamic Voltage Restorer (DVR) has been established as an effective solution for power quality improvement. This power electronic device operates by injecting compensating voltage into the distribution system through pulse-width modulation (PWM) techniques, typically controlled by digital signal processors (DSPs) or field-programmable gate arrays (FPGAs). The core algorithm involves real-time voltage monitoring using Fourier transform analysis to detect voltage deviations, followed by instantaneous calculation of required compensation voltage vectors. Key functions include phase-locked loop (PLL) synchronization for grid connection, voltage sag detection algorithms with programmable threshold settings, and proportional-integral (PI) controllers for precise voltage injection. The control system typically employs dq0 transformation for decoupled control of active and reactive power components, enabling rapid compensation within 1-2 milliseconds. This reliable solution protects sensitive equipment through fast-acting voltage compensation logic, with implementation featuring fault ride-through capabilities and harmonic filtering algorithms. The system architecture includes DC energy storage integration, voltage source converter (VSC) topology, and protection circuits with overcurrent monitoring functions. From an economic perspective, DVR installation represents a cost-optimized investment that reduces long-term equipment maintenance costs and minimizes production downtime through embedded fault prediction algorithms.