A 900W, 300V to 50V Dc-dc Power Converter with a 30MHz Switching Frequency

Designers of power conversion circuits are under relentless pressure to increase power density while maintaining high efficiency. A primary path to higher power density is the use of increased switching frequency. In this paper it is argued that the use of switching frequencies in the VHF band (30MHz-300MHz) are a viable path to the achievement of substantive gains in power density. Evidence for this viewpoint is presented in the form of an unregulated 900W prototype dc-dc converter with a 30MHz switching frequency, an input voltage range of 270VDC to 330VDC, and an output voltage of 50VDC. This converter uses a quad module architecture with series input and parallel output to provide acceptable efficiency with the specified input voltage range. This converter operates with peak output power of 1kW at 330VDC input, and has an efficiency of >78% under nominal conditions, with maximum efficiency near 80%.