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Constant-current vs. constant-power protected rectifier as a DC UPS system's building block

Research output: Contribution to journalConference articleScientificpeer-review


Original languageEnglish
Pages (from-to)227-233
Number of pages7
JournalINTELEC, International Telecommunications Energy Conference (Proceedings)
Publication statusPublished - 1 Dec 1996
Externally publishedYes
Publication typeNot Eligible
EventProceedings of the 1996 18th International Telecommunications Energy Conference, INTELEC - Boston, MA, USA
Duration: 6 Oct 199610 Oct 1996


Telecom systems have been powered by means of DC UPS systems for years. The emergence of digital exchange systems changed the nature of the load from resistive one to constant-power type. The basic active building block of a DC UPS system is a rectifier operating normally in parallel with several similar units as well as with a storage battery. The rectifier must be protected from overloading. All the overloading protection schemes are based on output current limiting. There are, in principle, three possible ways to implement the protection - constant-current, fold backing and constant-power. The constant-power type protection scheme seems to be the most ideal from the Telecom power system's view point, but there are, anyway, several parameters, which affects the optimum. When they are all taken into account, the constant-current protection scheme is as an economical or even more economical solution than the constant-power scheme. This paper will address the different parameters affecting the optimum and will explain the reasoning behind the ideas the authors have come up to.

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