Robust Frequency Lock Loop based Power Control and Harmonic Compensation Method for Bidirectional AC/DC Converter

The single-phase bidirectional AC/DC converter with current harmonic compensation and power flow regulation capability is the core unit in the household energy router. In this paper, an improved power flow control and current harmonic compensation method for the bidirectional AC/DC converter is presented. A robust Second-Order Generalized Integrator based Frequency Lock Loop (SOGI-FLL) with phase angle jump, DC bias and harmonic distortion rejection capability is proposed. The linearized model of proposed SOGI-FLL is analyzed. Compared with conventional power control and current harmonic compensation methods, the proposed SOGI-FLL can provide a great rejection to the grid current phase angle jump, thus makes the bidirectional AC/DC converter's current harmonic compensation more precisely and power flow control more quickly. The proposed close-loop control system based on novel SOGI-FLL for the bidirectional AC/DC converter shows a faster and smoother transient performance. Finally, the performance of the proposed close-loop control system was verified by simulation and experimental results.