Power generation on-board aircraft using an air-powered turbine generator and battery interface system

The design and implementation of a prototype hybrid power generation system, consisting of a ram air turbine (RAT) generator and an energy storage unit, is presented. The system is intended as a mechanism to supply additional or emergency power on-board an aircraft. Here we present the design, manufacture and testing of a synchronous rectifier required to interface an asynchronous generator to a dc bus. The dc bus connects to a battery of electrochemical cells through a bidirectional dc-dc converter. The dc-dc converter functions to regulate the dc bus voltage by utilising a double control loop strategy with an inner current control loop and outer voltage control loop. The power delivered to the dc bus from the generator is controlled as a function of the battery voltage, dc bus current and generator shaft speed. The control strategy used by the prototype circuit is presented in this paper along with simulation and experimental results.