Parallel Bus Joint Operation System of SVG and APF under Unbalanced Grid Conditions

Under unbalanced grid conditions, the parallel bus joint operation system of SVG (Static Var Generator) and APF (Active Power Filter) plays a crucial role in enhancing power quality. The SVG primarily handles dynamic reactive power compensation to regulate grid voltage stability, while the APF eliminates harmonic currents in the system to mitigate waveform distortion issues. In code implementation, SVG typically uses PWM (Pulse Width Modulation) control algorithms for rapid reactive power adjustment, while APF employs harmonic detection algorithms like FFT (Fast Fourier Transform) or instantaneous power theory to generate compensating currents.

When the grid operates under three-phase unbalanced conditions, the coordinated operation of SVG and APF becomes particularly critical. The SVG reduces voltage fluctuations and asymmetry problems through its fast-response reactive power compensation capability, implemented using dq-axis transformation control strategies. Meanwhile, the APF effectively suppresses harmonic pollution by detecting harmonic components and performing reverse compensation through current tracking control algorithms such as PR (Proportional Resonant) controllers or repetitive controllers. Their parallel operation on the same bus enables complementary optimization, improving both power factor and ensuring clean grid waveforms through coordinated control logic programmed in DSP or FPGA platforms.

IEEE literature has conducted in-depth research on this system, exploring optimization methods for control strategies such as harmonic detection algorithms based on instantaneous reactive power theory and coordinated control logic between SVG and APF. Through proper parameter setting and dynamic adjustment algorithms - often implemented using adaptive PID controllers or fuzzy logic control - the system can adapt to various degrees of grid imbalance and harmonic interference, thereby ensuring the safe and stable operation of the power system. The control system typically involves real-time calculation of positive and negative sequence components for unbalanced compensation.

This technology finds applications not only in industrial power systems but also extends to renewable energy generation grid integration, rail transit power supply, and other fields, providing essential support for the efficient operation of modern power grids. The implementation often includes communication protocols like MODBUS or IEC 61850 for system integration and remote monitoring capabilities.