Fuzzy controller based on input current slope for a three-stage cascaded boost converter

A novel fuzzy controller based on an input current slope for a three-stage cascaded boost converter is presented for high-voltage DC applications. The control objective is to achieve satisfactory converter performance, facing not only variations in load resistance and renewable energy source voltage but also in the interaction of the individual converter in each stage. The intricate configuration nature of multi-stage cascaded boost converter renders the mathematical model complex, which is perplexing for the design methodology of controllers. In response to these challenging problems, the fuzzy controller can function without a precise mathematical model. It uses an understanding of the converter behavior to develop control rules that imitate human decision making. In addition to controlling the output voltage, the proposed fuzzy controller in this paper can manage the input current along with the reference current slope without overshooting or taking a long time to settle. The input current slope and the output voltage error are determined with suitable membership functions and their intervals. The fuzzy output is a change in duty, linguistically associated with the system inputs through 15 fuzzy rules. The simulations and experimental results indicate that the output voltage of 400 V is finely regulated with robustness. In addition, the results imply that performance performs effectively in both transient and steady states, even when the converter functions under conditions of fluctuating load resistance, input voltage, and desired output voltage.