Fig.1

Configuration of three-phase LCL grid-connected inverter

Fig.2

Control structure for three-phase grid-connected inverter based on PBC

Fig.3

Norton equivalent model of LCL grid-connected inverter

Fig.4

Real part of the output admittance Yo(s) of grid-connected inverter versus frequency at different r1 values

Fig.5

Step responses of G(s) at different r1 values

Fig.6

Block diagram of damping enhancement control based on capacitive current feedforward

Fig.7

Bode wave of Yo(s) at different proportional feedback coefficients and Ygt (s) values

Fig.8

Bode wave of Yo(s) at different HPF feedback coefficients and Ygt(s) values

Fig.9

Simulation waves of grid currents of different capacitor current feedback methods (Lg=0, Cg=0)

Fig.10

Bode waves of Yo(s) and Ygt(s) without capacitor feedforward at Lg=0 and Cg=0

Fig.11

Simulation waves of grid currents of different capacitor current feedforward methods (Lg=3.6 mH, Cg=2 μF)

Fig.12

Simulation waves of grid currents of proposed control method in distorted grid (Lg=3.6 mH, Cg=2 μF)

Fig.13

Experimental waveforms of proposed control method (Lg=3.6 mH and Cg=3 μF)

Fig.14

Dynamic experimental waveforms of proposed control method (Lg=3.6 mH and Cg=3 μF)

Fig.15

Experimental waveforms of proposed control method at disabled HPF feedback (Lg=3.6 mH, Cg=3 μF)

Fig.16

Experimental waveforms of proposed control method at grid background harmonic voltage (Lg=3.6 mH, Cg=3 μF)