Study of Voltage Feedforward Damping Control Strategy for Grid-Connected Inverters Operating in Weak Grid Conditions

Weak grid circumstances can prompt resonance thereby jeopardizing the secure and steady operation of the entire power supply network. To enhance the stability margin of the grid-connected inverter while upholding its output traits, this study delves into the grid voltage feedforward control strategy for the inverter amidst feeble grid conditions. The output conductance model extensively examines the integration of grid voltage feedforward within the inverter's control loop, employing proportional control, proportional weighted control, and multiple resonance control, each with distinct weighting schemes. The stability of the inverter across diverse control approaches is evaluated using a passive stability criterion. Consequently, a feedforward control strategy employing multi-resonance with variable weighting ratios is proposed. This ensures stability and augments harmonic suppression potential, especially in the presence of feeble grid conditions. The practicality of the proposed strategy is substantiated through simulation and experimentation.