Phase shifted bridge converter for a high voltage application

In airborne applications, the size and weight of equipment are critical parameters. The power supply for an airborne radar needs to have a high output power density while operating with a high efficiency. Conventional Travelling Wave Tube (TWT) radars require a high voltage power supply for operatio...

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Bibliographic Details
Main Author: Loh, Chee Keong Richard Marcus
Published: University of Edinburgh 2003
Subjects:
Online Access:http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654009
Description
Summary:In airborne applications, the size and weight of equipment are critical parameters. The power supply for an airborne radar needs to have a high output power density while operating with a high efficiency. Conventional Travelling Wave Tube (TWT) radars require a high voltage power supply for operation and is prone to arcing. As the radar is a crucial piece of equipment, its power supply must be designed to withstand such operation. The Phase Shifted Pulse Width Modulation Zero Voltage Switching Full Bridge Converter has been the subject of many papers due to its ability to provide high output powers with high efficiency. As the output inductive/capacitive filters used by the present low voltage, high current, phase shifted converters are unsuitable for high output voltage applications, it is replaced with a capacitive filter, altering the basic operation of the converter. In this thesis the theory and design implementation of the Phase Shifted Bridge with Capacitive Filter (PSBCF) is described. Two auxiliary circuits developed for the conventional phase shifted bridge are analysed and implemented in the new PSBCF. Detailed cycle-by-cycle transient simulations on PSPICE are used to study the converters' behaviour and these are verified with experimental results. An averaged model of the PSBCF running in PSPICE is described and verified using the cycle-by-cycle transient simulations. Finally, the features and limitations of the PSBCF converter and the use of the auxiliary circuits are discussed and evaluated against each other and against the currently used airborne TWT radar power converter to demonstrate that this technology is a viable replacement.