Page 299 - 2024-Vol20-Issue2

295 | Abdulabbas & Salih

100

Mag (% of Fundamental) 80

60

40

20

0 10 20 30 40 50
0
Harmonic order

Fig. 14. The spectrum of the grid current phase A. Fig. 17. Responses of capacitors and output voltage of qZS
network variables.

overshoot and settling time. has been accomplished and the total of the voltages across two
Fig. 17 displays the steady-state responses of the qZS net- capacitors is equal to the input voltage applied to the inverter.
Fig. 18 illustrates the relationship between grid current total
Fig. 15. d-q axis grid current. harmonic distortion (THD) and Kcd, as determined through
scientific means, for various Io values. The total harmonic
distortion (THD) values observed for a current of 10A are
slightly higher than those reported for a current of 20A, given
the identical Kcd values. It is evident that Fig. 17 can be
partitioned into two distinct sections. Within the initial re-
gion, the total harmonic distortion (THD) of the grid current
reduces when the value ofKcd is raised from 2 to 4. As the
value of Kcd is raised from 4 to 6 in the second region, the
total harmonic distortion (THD) of the grid current begins
to rise. The evidence indicates that increasing Kcd can have
both beneficial and detrimental impacts on the damping of the
capacitor voltage loop.
The suggested control strategy has been compared to existing
linear and nonlinear control methods, including the active
damping method proposed in [4], the SMC-based control
method proposed in [8], the composite nonlinear feedback
control method proposed in [10], and the feedback-based PR
current control method proposed in [16]. Tables II presents
a summary of the comparison between four control methods
and the suggested control approach. The proposed control
approach, which combines both linear and nonlinear control
strategies, presents numerous advantages in comparison to
using linear and nonlinear control strategies alone.

Fig. 16. d-q axis capacitor voltage. IV. CONCLUSION

work variables for VC1 = 600 V and VC2 = 200 V. Once The suggested method utilizes a Lyapunov function to op-
again, it is evident that the successful control of VC1 and VC2 erate a three-phase grid-tied qZSI (quasi-Z-source inverter)
with an LCL (inductor-capacitor-inductor) filter. While the
utilization of LCL filter offers notable benefits, it also presents
certain downsides, including the potential for instability and