A Simplified Approach to Closed Loop Control of A Non-Isolated Bidirectional DC To DC Converter

This paper aims at implementing a smart., light weight and economical DC to DC converter topology in closed loop mode in order to design an uninterrupted power supply to the electronic and auxiliary loads in a More Electric Aircraft with high efficiency and good transient and steady state response. The proposed topology uses a non-isolated cascaded bidirectional DC to DC converter which can be used in buck as well as boost mode. The aircraft load which is to be supplied with DC power is so connected that it can take power from AC generator mounted on the engine shaft as well as from an auxiliary battery which gets connected to the load in case the engine gets overloaded due to takeoff., landing or turbulence conditions. The changeover between these two sources happens automatically and appropriate gate signals are provided to the semiconductor switches in the DC to DC converter with the help of closed loop control consisting of PI voltage controller hysteresis current controller. The system performance is tested under randomly varying load conditions and the load voltage and current waveforms are compared against their respective reference values. The system transient response is evaluated in terms of overshoot and voltage regulation across the load. PI controllers can be replaced with more advanced controllers like sliding mode controller or fuzzy controller in order to get even better system response in terms of load current overshoot under changing load conditions.