Voltage H Repetitive Control with a Frequency-adaptive Mechanism - Control of Power Inverters in Renewable Energy and Smart Grid Integration - page 121

30 30

u ref u A u ref u A

15 15

0 0

−15 −15

−30 −30

4 4

e u e u

2 2

0 0

−2 −2

−4 −4

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Time [s] Time [s]

(a) f = 50 . 05 Hz

30 30

u ref u A u ref u A

15 15

0 0

−15 −15

−30 −30

4 4

e u e u

2 2

0 0

−2 −2

−4 −4

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Time [s] Time [s]

(b) f = 50 . 10 Hz

30 30

u ref u A u ref u A

15 15

0 0

−15 −15

−30 −30

4 4

e u e u

2 2

0 0

−2 −2

−4 −4

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Time [s] Time [s]

(c) f = 50 . 15 Hz

Figure 5.15 Responses when the grid frequency was above 50 Hz: with the frequency-adaptive mech-
anism (left column) and without the frequency-adaptive mechanism (right column)