New technique proposed for high accuracy, low cost current measurement

November 04, 2013 // By Christoph Hammerschmidt
Cambridge, UK, based product design consultancy 42 Technology has proposed a novel approach for polyphase current measurements; using a topology that does not require expensive current transformers, it results in significantly lower cost, the company says.

According to 42 Technology, omitting current transformers enables them to offer the desired functionality at a price up to 30% lower than comparable devices with transformers. In addition, 42T's topology is more robust since it is inherently immune against strong DC magnetic fields. Products based on a current transformer can be disabled with strong magnets. To avoid this, manufacturers need to incorporate significant magnetic shielding, which adds extra cost, complexity and bulk. In addition, the 42 Technology approach also offers isolation voltages of up to 15 kV whereas existing technologies reach only 12 kV or even less. The technology also is capable to measure alternating currents at frequencies in the MHz region.

The technology devised by 42 Technology is based on a resistive sensing topology - already the preferred approach for single-phase meters. The company claims it has succeeded in transferring this technology to multi-phase metering with performance gains, and also benefits in manufacturing.

42 Technology says it has working prototypes and is looking for partners to commercialise its technology. Referring to the IP reasons as well as client confidentiality the company however declined to provide further details.

42 Technology;  www.42technology.com