Figure 10. Comparison of Output Voltage for SEPIC and FOSEPIC Converters
with FOSMC and IOSMC in Boost Mode Operation
Figure 10 presents a comparison of output voltage for both SEPIC and
FOSEPIC converters under boost mode operation, highlighting the
performance of different controllers. Panel (a) displays the results for
the FOSMC with fractional order model (FOM) in [Red], while panel
(b) shows the IOSMC with integer order model (IOM) in [Blue]. Panel
(c) illustrates the FOSMC with IOM in [Black], and panel (d) depicts
the IOSMC with FOM in [Magenta].
In both Figures 9 and 10, oscillations in the output voltage can be
observed during the comparison between FOSMC and traditional SMC. The
differentiation order is a critical factor, with integer orders used in
IOM systems and fractional orders in FOM systems. This flexibility in
fractional orders allows for richer dynamics and better tuning
capabilities, making FOM an attractive option for control strategies.
Fractional-order control has emerged as a robust approach, effectively
managing system uncertainties and disturbances while incorporating
nonlinear dynamics. The combination of fractional-order control with SMC
leads to the development of fractional-order sliding mode control
(FOSMC), which improves upon traditional integer-order SMC.
Conclusion
This study successfully introduces a Fractional Order Sliding Mode
Control (FOSMC) strategy with a simplified sliding surface function
tailored for DC-DC FOSEPIC converters. By leveraging the input inductor
current error, the proposed control method enables indirect regulation
of output voltage, which significantly simplifies both the simulation
process and the mathematical modeling involved. Extensive simulations
conducted in MATLAB/SIMULINK under various operational conditions
validate the performance of the FOSMC, showcasing its superior
flexibility and enhanced control compared to traditional integer-order
methods.
Additionally, this research pioneers the development of fractional-order
models for SEPIC converters, offering a comprehensive framework that
accurately captures their operational characteristics. The findings
reveal that SEPIC converters equipped with fractional-order inductors
and capacitors exhibit markedly improved dynamic performance,
characterized by reduced overshoot and shorter regulation times when
compared to conventional designs.
Overall, the integration of fractional-order control into sliding mode
strategies not only enhances the robustness and performance of power
conversion systems but also opens new avenues for future research and
application. This innovative approach holds significant promise for
advancing the efficiency and reliability of power electronics,
particularly in the context of renewable energy systems and electric
vehicle technologies. The results underscore the potential of
fractional-order control as a key enabler for next-generation power
management solutions, paving the way for more adaptive and
high-performance systems in the field.