Modeling and control of a new circuit to obtain hold-up time extension for electronic equipment in aircraft applications

This paper introduces a new hold-up time extension circuit (HTEC) with potential use in aircraft applications. The circuit is composed of a bidirectional version of the conventional buck-boost converter operating in Boundary Conduction Mode (BCM) and the corresponding control. The converter is used to charge and discharge an auxiliary capacitor used to store the energy required to extend the operation time in the case of a failure in the a DC power distribution bus. The proposed control uses two cascaded controllers with internal loops defining the maximum current and outer loops defining the regulated voltages of the auxiliary capacitor and DC bus respectively. The theoretical analysis and the design of the circuit are validated by means of simulation results.