Design of a Fuzzy Gain Tuned Hybrid Posicast Control for Buck-Boost Converter with Negative Output

This paper presents the Fuzzy Gain Tuned Hybrid Posicast Control (FGTHPC) for a Negative Output Buck Boost Converter (NOBBC) operating in Continuous Conduction Mode (CCM). FGTHPC reduces the peak overshoot of the lightly damped NOBBC with step response. Traditional Proportional Integral Derivative (PID) control is highly sensitive to the changing natural frequency of oscillations within NOBBC. In this paper, an FGTHPC has been designed to operate the same converter in a closed loop to reduce the sensitive oscillation and output voltage regulation for the NOBBC. A controller having a posicast structure and a feed-back loop is designed. Here, Fuzzy Logic Controller (FLC) is used to optimize the parameters value of the Hybrid Posicast Control (HPC). The posicast function is designed in order to operate independently of the computational time delays. For performance evaluation, FGTHPC applied to the NOBBC is tested under different operating conditions using an LED string load supplied by a battery and solar panel. Both MATLAB/Simulink simulations and experimental prototypes are developed, and results are compared with those obtained from a PID controller and a HPC. The results will establish the superiority of the designed FGTHPC in comparison with PID control.