Modelling and control of dual input boost converter with voltage multiplier cell

Abstract

A dual input DC-DC converter with dual boost and integrated voltage multiplier cell operating at duty cycles larger than 0.5 is a necessity to achieve a high voltage gain for energy systems possessing two independent renewable energy resources. Output voltage regulation during load changes and input disturbances is the requisite of an energy system, which is achieved by the implementation of a suitable control action, which further requires the dynamic model of the converter. The modelling of this higher order converter with overlapping switching signals is complicated. The small-signal transfer function model based on state-space averaging followed by small-signal linearisation is verified using MATLAB and powersim (PSIM). The output voltage to duty cycle transfer functions significantly contributes to representing the converter dynamics from which its right-half s-plane zero is analysed. Since it is a non-minimum phase system, a dual loop control strategy is adopted. Voltage regulation and active current sharing are ensured from the simulation and experimental responses of the uncompensated and compensated systems. Further, from the derived integer-order converter model a fractional controller is designed and its dynamic response is compared with the traditional controller. A 200 W prototype of the converter is developed, and the control is implemented using field-programmable gate array.