Design and Fabrication Of Electronic Power Conditioner For Power Amplifier

Abstract

This report describes the detailed design of High Efficiency DC-DC converter with 75W output power required for Power Amplifier. The converter consists current mode control boost preregulator, half bridge converter and control circuit design of this converter is carried out at high switching frequency. This high switching frequency is necessary to reduce size and weight of DC-DC converter. However this yields high switching losses consequently low efficiency in hard switching. ZVS quasi-resonant converters which are designed to reduce switching losses, but the reduction of switching losses in these converters results in conduction losses by increase in voltage and current stress of switches. So Zero voltage transition technique in Boost preregulator is opted here, which gives minimum semiconductor stress and low losses. Zero voltage transition boost preregulator is connected at the previous stage in order to increase the efficiency of the power supply and reduce un-acceptable switching losses in the power devices. Output of this preregulator is given to the Half Bridge converter that follows diode rectification and filtering. This report describes all design steps, detailed derivations of design equations, observed waveforms and efficiency results for both Boost preregulator and Half Bridge Converter. This High efficiency Converter can be used for firing Gallium Arsenide FETs of Solid state power amplifier used in space applications.