ADI wants to take the transformer out of meter design

Analog Devices says it can take the need for an isolating transformer out of energy metering designs. 

It proposes the use of an isolated 3-channel, sigma-delta A/D converter in polyphase energy meter designs which uses the firm’s iCoupler and isoPower technologies to implement isolated signal transfer and dc-to-dc power conversion across a 5kV-rated insulation barrier. 

“This enables the use of shunt resistor sensing elements instead of current transformers (CTs), thereby providing immunity to magnetic field interference and tampering,” said the supplier.

“In the past, polyphase meter manufacturers had to decide between CT-based architectures vulnerable to external magnetic fields, or discrete component shunt-based architectures involving excessive complexity and functionality compromises,” said Ronn Kliger, director for the energy group, Analog Devices. 

“Now, with an integrated component incorporating synchronised A/D conversion and galvanic isolation, our customers can develop feature-rich, cost-effective metrology solutions that are completely immune to magnetic interference,” said Kliger.

The ADE7913 three channel A/D converter has one current channel and two voltage channels. Up to four devices can be synchronously clocked from a single crystal or an external clock.

There is also on-chip temperature compensation and integrated voltage reference.

A standard SPI serial interface will support third party microcontrollers.

There is also the EVAL-ADE7913EBZ evaluation board.

ADI also recently announced an isolated metrology chipset designed for polyphase energy metering applications that provides state-of-the-art 3-phase metrology measurements and power quality monitoring.

The ADE7978 metrology chipset includes the ADE7978 3-phase metrology IC combined with up to four ADE7933 fully isolated A/D converter ICs.

The ADE7933 3-channel sigma-delta A/D converter incorporates Analog Devices’ patented iCoupler and isoPower technologies to implement isolated signal transfer and dc-to-dc power conversion across a 5kV-rated insulation barrier. 

This enables the use of shunt resistor sensing elements instead of current transformers, thereby providing immunity to magnetic field interference and tampering. The use of shunts instead of CTs also reduces system cost and size.

www.analog.com/ADE7978/

www.analog.com/ADE7913

 


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