Telecom Rectifier Boasts 96% Efficiency

Jan 30, 2008 4:41 PM

by David Morrison, Editor-in-Chief, Power Electronics Technology

Eltek Valere’s new 2000-W ac-dc rectifier for telecom applications boosts typical efficiency from the 92% available from some existing rectifiers to 96%, cutting rectifier power losses in half (see the figure on bottom of page). To achieve this performance, the Flatpack2 HE Rectifier Module 48/2000 employs digital control along with a combination of hard-switched and soft-switched (resonant) converter topologies. According to the vendor, the use of digital control also enables a 40% reduction in the number of components required for the system, which results in increased reliability.

According to the vendor, the Flatpack2 HE is the first in a line of high-efficiency rectifiers from Eltek Valere that will help telecom carriers reduce their power consumption dramatically. The Flatpack2 HE is a standalone 48-V rectifier and battery charger that provides up to 2000 W of power from a single unit. Alternatively, multiple rectifiers can be combined to achieve power outputs up to 100 kW for systems like those found in central offices.

As shown in the figure, the Flatpack2 HE achieves its maximum efficiency at about 50% loading, which according to the company is where most rectifiers typically are operated. The efficiency curves shown reflect an input voltage of 230 Vac and an output of 48 Vdc.

The Flatpack2 HE being measured in the figure has an input voltage range of 180 Vac to 300 Vac. When the rectifier is operated at the low end of this range, efficiency can be expected to drop by about 1% according to the company. Similarly, when the unit is running at the high end of its -40°C to 85°C operating temperature range, a slight degradation in efficiency can be expected.

Also, when output voltage is set at a value below 48 Vdc, the efficiency will decrease. However, according to the vendor, it’s more likely that the output voltage will be adjusted upwards to 54 Vdc for charging VRLA batteries.

The Flatpack2 HE features a controller area network (CAN) bus interface to allow it to communicate with Eltek Valere’s Smartpack controller or to be integrated into customer cabinets. The Smartpack controller provides full control and monitoring of rectifiers and other system elements. The Smartpack module has advanced system monitoring with multilevel access and comprehensive battery management. The Smartpack allows remote management via the Web, SNMP, SMS, e-mail or modem.

The rectifier has a maximum output current of 41.7 A. It provides the rated 2000 W output over the 180 Vac to 300 Vac input voltage range, but will operate at voltages down to 85 Vac with derated performance.

The Flatpack2 HE features protection capabilities such as overvoltage shutdown, blocking diode, short circuit and high temperature protection. The module has a front-to-back airflow with chassis-integrated heatsinks. Because of their operating temperature range and small size (approximately 1 U x 4 in. x 12. in.), Flatpack2 HE rectifiers are deemed well suited for use in remote applications.

Now sampling, the Flatpack2 HE Rectifier Module 48/2000 is currently in pre-production with full production expected April 1. Unit pricing starts at $450. To request a datasheet, see www.eltekvalere.com/green.

EltekValere’s Flatpack2 HE provides a 4% increase in efficiency over existing 48-V, 2-kW telecom rectifiers such as the company’s Flatpack2. (VIN = 230 Vac, VOUT = 48 Vdc)

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