Small-Signal Modeling of a Resonant SCC for PWM, Phase-Shifted and Frequency Modulation Control Approaches

Resonant switched-capacitor converters (SCC) are widely used in many applications, due to their good features such as soft switching operation, low electromagnetic interference, high-switching operation, high-power density, and low volume and size. The output voltage regulation issue is one of the main disadvantages of the SCCs when their output loads and input voltages are changing in wide ranges, which can be overcome easily by using them as resonant converters. These resonant structures need accurate small signal modeling to well regulate their output voltages by using closed-loop control approaches. Here, based on the extended describing function (EDF) method, the large and small-signal models are studied for a resonant SCC, which consists of PWM, frequency modulation, and phase-shifted control methods. Finally, to confirm the proposed small signal model, its responses are compared with the simulation results of the given resonant SCC, which clearly indicate high accuracy of the proposed small-signal model.