Figure 12 (a) and 12 (b) shows the simulation results on
the output voltage of the open loop and closed loop
circuit. At output voltage of the open loop circuit
showed that voltage boost up for a value of 72 V. This
showed that open loop circuit produced an overshoot
voltage however this scenario did not happen in closed
loop circuit. In closed loop circuit the output voltage
boost up till 40 V. The fuzzy logic controller plays it
roles to control the voltage output as the desired
requirement. It proved that the fuzzy logic controller
successfully control the overshoot value better than
system without fuzzy logic controller with the same
input voltage 20V and the settling time for the closed
loop converter is much faster.
Next take a look at the output current simulation results
on Figure 13(a) for open loop circuit and Figure 13(b)
for closed loop circuit. The system with fuzzy logic
controller had controlled the current of output by driving
it to produce the desired current that needed by the
system and eliminating the overshoot current. The
scenario is at the inductor current simulation results
when the inductor current closed loop circuit and the
settling time for the closed loop converter is much
faster. Figure 14(b) shows a constant value very fast.
Neither happened on the inductor current of open loop
circuit in Figure 14(a). It did not give a constant value
very fast and moreover it also produces a high overshoot
value on the early stage. Thus, the comparison on
simulation results between open loop circuit and closed
loop circuit obviously can be continued in determining
on the others components in the circuit such as capacitor
voltage results in Figure 15(a) and 15(b). All the
simulation results between open loop circuit and closed
loop circuit shows that the closed loop circuit gives a
fast settling time value that was controlled by fuzzy
logic controller. This purposely achieved in order to
correspond on the output desired of the system.