Fractional-Order Approximation of PID Controller for Buck-Boost Converters.

Area of Science:

• Electrical Engineering
• Control Systems
• Applied Mathematics

Background:

• Buck-boost converters are crucial for power management in diverse applications, from high-power systems to micro/nano-scale biomedical devices.
• Traditional proportional-integral-derivative (PID) controllers face limitations in regulating non-minimum phase systems.
• Fractional calculus offers enhanced modeling capabilities for complex dynamic systems.

Purpose of the Study:

• To investigate the viability of a fractional-order proportional-integral-derivative (PID) approximation for voltage regulation in buck-boost converters.
• To develop a robust and high-performance fractional-order PID controller.
• To demonstrate the superiority of the proposed controller over traditional PID controllers.

Main Methods:

• A closed-loop control diagram was employed to assess controller effectiveness.
• Fractional calculus was integrated using a Laplacian operator biquadratic approximation for improved frequency response.
• Controller synthesis focused on robustness and closed-loop performance, with a simple tuning method for gain determination.

Main Results:

• The fractional-order PID controller demonstrated a flat phase curve in the closed-loop frequency response.
• The proposed approach yielded superior time constants compared to typical PID controllers.
• Experimental validation using resistor-capacitor (RC) circuits and operational amplifiers (OPAMPs) confirmed the controller's effectiveness.

Conclusions:

• Fractional-order PID control is a viable and effective alternative for voltage regulation in buck-boost converters.
• The proposed method offers improved stability and performance, especially for non-minimum phase systems.
• The experimental results validate the theoretical findings and practical applicability of fractional-order PID control.