Investigation of stabilities of Lyapunov-Based digital control for grid-connected inverter

Design of Passivity-Based Stabilized Control of Grid-Connected Inverter System with LCL Filter

“…An example of such a control method is the energy function-based Lyapunov function method. [5][6][7][8] While energy function-based control methods are stable, design freedom is partially sacrificed to ensure stability and there is a disadvantage in that the tracking of the output current to the sinusoidal waveform is loose. 7 Conventionally, control methods that are both stable and that have tracking performance to the sinusoidal waveform are desirable.…”

Design of passivity‐based stabilized control of grid‐connected inverter system with LCL filter

“…If the output admittance of the grid inverter is passive, that is, the conductance component of the frequency characteristics is constantly positive and the variation range of the phase is within ±90°, Nyquist's stability condition will always be satisfied and stability can always be ensured, regardless of the grid impedance value. An example of such a control method is the energy function‐based Lyapunov function method . While energy function‐based control methods are stable, design freedom is partially sacrificed to ensure stability and there is a disadvantage in that the tracking of the output current to the sinusoidal waveform is loose …”