Design and Development of Compact DC-DC Converter Unit from Air Craft

Abstract

Efficient conversion of Electrical power is becoming a primary concern to aircrafts. Switching power supplies (SMPS) offer not only higher efficiencies but also offer greater flexibility to the designer. This paper depicts an overview of all the issues involved in designing S.M.P.S. It describes the operation of the fly back topology, its relevant parameters, circuit design tips, and information to select the most suitable semiconductor and passive components. Regulation of the output is carried out by the feedback concept. S.M.P.S. operates on a fixed frequency pulse width modulation basis compensates for changes in the input and output load. The error voltage is used by dedicated control logic to terminate the drive pulse to the main power switch at the correct instance. Delays in the control loop are kept to a minimum, Hence, very high speed components must be selected for the loop.  Electronic isolation is achieved by using an opto-isolator S.M.P.S. topology contains a power transformer provides isolation, voltage scaling through the turns ratio, and multiple outputs. In this proposed project, dc-dc converter fly back technology is found as more effective in terms of cost, size & performance. Converter is specially designed and developed for tight regulation with special considerations to satisfy the operating conditions of critical loads in aircrafts. The fly back converter switching power supply is the best choice for output 10 watts to 120 watts with multiple outputs.

Keywords:SMPS, PWM, regulation, flyback, Isolation, duty ratio, actuators