Coordinate Control of Power/Current for Grid-Connected Inverter Based on PCI Controller under Unbalanced Grid Conditions

Table 3

Control performance comparison of the coordinate control under different cases.

		Case a		Case b		Case c
		Control in Ref. [20]	Proposed control	Control in Ref. [20]	Proposed control	Control in Ref. [20]	Proposed control
Current THD of phase-A (%)	0.1 s~0.2 s	3.75	1.59	4.65	2.37	4.82	3.35
	0.2 s~0.4 s	5.77	5.75	7.38	6.24	8.25	7.46
	0.4 s~0.5 s	10.62	7.00	11.73	8.26	24.88	10.15
DC-link voltage ripple (%)		0.47	0.21	0.21	0.18	0.51	0.27
Settling time (s)		0.10	0.10	0.09	0.10	0.12	0.11
Overshoot of DC-link voltage (%)		1.91	0.54	2.72	0.49	3.46	0.34
Amplitude of active power oscillations (% of P)		28.10	21.48	28.91	25.71	40.91	35.46
Amplitude of reactive power oscillations (% of P)		23.18	20.08	22.89	16.99	39.73	30.77