Fractional-order controllers for switching DC/DC converters using the K-factor method: Analysis and circuit realization

Switching DC/DC converters are closed loop systems requiring controllers to stabilize and optimize their performance. A practical method for designing these controllers through pole/zero placement adjustment is the K-factor method. This method can easily be implemented using RC op-amp circuits given a target crossover frequency and phase margin. Here, we extend this method to the fractional-order domain and present detailed analytical formulae to calculate all component values in two types of op-amp-based compensators. Mathematical analysis, circuit simulation, and experimental results all correlate very well.