Important system design concepts for a modular DC rack power system featuring a single mode rectifier

The size reduction which has occurred in power conversion equipment due to the introduction of high frequency switching techniques has enabled the introduction of versatile and modular approaches to the system design of DC power plants for telecommunications applications requiring very high reliability DC power. It is argued in this paper that many requirements often written into DC power supply equipment specifications are irrelevant or of low priority when applied to the new technology. They are typically left-overs of the needs which were relevant to the older phase-controlled equipment. Issues regarding the use of circuit breakers, forced convection, extensive alarm annunciation and single as opposed to three phase input are explored and tested for their relevance. An example of a single phase input, fan cooled, 100 A, 48 V rectifier/battery charger designed with these principles in mind is described to demonstrate the very significant gains achieved in size and cost.