Andronov–Hopf Oscillator-Based Phase-Locked Loop for Three-Phase Grid Connected Inverters

This letter proposes a virtual oscillator phase-locked loop (VO-PLL) that integrates an Andronov-Hopf oscillator to improve synchronization in distorted grid. VO-PLL replaces the conventional proportional integral (PI) and resettable-integrator in traditional PLL, with a nonlinear Hopf oscillator known for its ability to sustain orbitally stable limit cycle oscillations at specific frequency. Inherent nonlinear dynamics of oscillator results in fast dynamic performance, harmonic rejection, and improved frequency tracking. Experimental tests show strong evidence for the effectiveness of the proposed VO-PLL, demonstrating its potential to enhance grid synchronization and imitate the operation of a higher order PLL under grid disturbances.