SIMULATION STUDIES ON AUTOTRANSFORMER RECTIFIER UNIT FOR AIRCRAFT APPLICATIONS

The need of High Voltage DC (HVDC) in aircraft is increasing due to use of electric power to drive aircraft subsystems such as an actuators which are used in landing gears, flap angle and rudder system of an aircraft. Actuators are mainly operated with a high DC voltage of 270V as an input power supply requirement. But in the conventional aircraft, DC voltage generation is limited to 28V by using transformer rectifier unit (TRU). So to cope up with the requirement, an additional conversion unit of Autotransformer Rectifier Unit (ATRU) is necessary. This paper presents study on ATRU. ATRU is a essential component of aircraft Electrical Power System (EPS). ATRU is fed with three-phase 115V 400 Hz AC voltages and converts to high DC voltage of 270V which is designed to supply high voltage DC bus of aircraft EPS. ATRU generates 270V DC with less harmonic contents. The DC voltage can be generated by using 18-pulse ATRU and 24-pulse ATRU. Hence, an 18-pulse & 24- pulse ATRU was designed modeled and simulated using the MATLAB-Simulink Software to understand the influence of harmonic contents.