Approximation of Optimized Fuzzy Logic Controller for Shunt Active Power Filter - Complex System Modelling and Control Through Intelligent Soft Computations - page 574

Load Current (Phase A)

20

0

-20

Source Current (Phase A)

40

20

0

-20

-40

Filter Current (Phase A)

10

0

-10

DC Link Voltage & Ref. Voltage

700

680

660

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65

Time (sec)

Fig. 12 Dynamic response of shunt APF with 49-rule FLC using triangular MFs

transient However, le obtained using triangular MFs is slightly

inferior to other MFs, which show better immediacy with each other.
In Case-1, the transient and steady-state response, as well as harmonic com-
pensation provided by FLC with Gaussian MFs is superior to other MFs.

the THD pro

4.2 Case-2: Load Perturbation Response Followed by Sudden
Reduction in Load

In this Case-2, at 0.25 s, the load current is suddenly reduced from 13.83 to 6.95 A
(rms), as evident from the waveforms shown in Figs. 12 , 13 , 14 and 15 . The
comparison of performances of various controllers regulating the DC link capacitor
voltage is presented in Table 3 .
Here, the peak overshoot in capacitor voltage due to load change is least with
triangular MFs, followed by Dsig, Gaussian and Gbell. But due to inferior switch-
on response of Gbell and Dsig MFs based FLCs, Gaussian MFs and Triangular
MFs based FLC are the true contenders. The settling times of both of them are less
than two cycle of fundamental frequency as shown in Table 3 . These observations