Design of 1.4kw telecom rectifier delivering full power from 90Vac to 300Vac

In the fast growing field of telecommunications, the back up DC power supply plays a vital role in powering the telecom equipment. This DC power supply is a combination of AC-DC rectifier coupled with a battery bank to support the load when AC input is not available. The power supply is the most critical element in a telecom installation and it should be highly reliable in order to have un-interrupted service. Besides reliability, power density and cost are the driving forces behind the success of a power supply in the market. Off late, the reach of telecom in the society is very wide covering remote villages and major metres. Given this environment, the power supply is exposed to extreme input conditions. It is desirable to design the power supply capable of withstanding wide AC input conditions. Another advantage is that the rectifier unit will keep the battery charged so that the battery will have long life. The aim is to design a switched mode rectifier (SMR) that tolerate wide input voltage variations (90Vac to 300Vac) delivering full rated power in the entire operating range. In addition, the design covers unity input power factor, high efficiency (> 93%), high power density, parallel operation and low cost. This design uses the popular boost PFC front-end converter followed by DC-DC converter section based on full-bridge topology. This paper details about the per unit description of the power converters, challenges involved in the design selection and the design of the proposed power supply unit, keeping in view of the issues expressed above. The normalized description of the power converters is presented in this paper. Such a description enables one to compare several circuit topologies in order to make effective design decisions [3]. In a similar way the effectiveness of the switches and magnetics are presented to enable design decisions in the output stage of the rectifier.