Small Signal Analysis of a Buck-Boost Four Port Converter BB-FPC

This work presents the development of a small-signal model for a buck-boost four port DC-DC converter (BB-FPC). A BB-FPC is composed by two Buck-Boost converters connected in parallel and a Phase-Shifted PWM Converter serving a load through a transformer and a rectifier and has three control inputs: two duty cycles and a phase shift. The small-signal model presented in this manuscript describes the interaction between the three controllable inputs and the voltage and currents in each port, and is developed by means of circuit analysis neglecting the AC interface under some design assumptions. Simulation results show that the small-signal model adequately resembles the behavior of the converter in time and frequency.