Non-Contact Voltage, Current, and Flow Monitoring

Technology #16022

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Inventors
Professor Steven Leeb
Department of Electrical Engineering and Computer Science, MIT
External Link (www.rle.mit.edu)
James Paris
Department of Electrical Engineering and Computer Science, MIT
John Donnal
Department of Electrical Engineering and Computer Science, MIT
Jin (Jinyeong) Moon
Department of Electrical Engineering and Computer Science, MIT
Christopher Schantz
Department of Mechanical Engineering, MIT
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Non-Intrusive Monitoring

US Patent Pending 2014-0320125
Publications
Noncontact Power Meter
Sensors Journal, IEEE, Sept. 19, 2015, pg. 1161
Water Nonintrusive Load Monitoring
Sensors Journal, IEEE, April. 4, 2015, pg. 2177

Applications

This technology measures magnetic and electric fields to non-intrusively monitor electrical voltage and current.  When coupled with a device that produces magnetic fields, this technology can also measure flow rates, such as water usage, and monitor industrial processes.

Problems Addressed

Monitoring real-time usage of a consumable could drastically improve the efficiency of the supply system.  However, installing monitoring devices often require substantial technical skill and disruptions to service.  This monitoring technology, in contrast, can be installed easily in existing systems while they are running.

Technology

Tunneling magnetoresistive (TMR) sensors, which measure magnetic fields, are the basis of this technology. When mounted close to an electrical cable, the sensors can determine the electrical current and voltage flowing through the cable by measuring the resulting magnetic field. Feedback loops attached to the TMR sensors ensure that they operate within the linear regime for more accurate readings. If several wires are close together so that theur magnetic fields interact, such as within a circuit breaker box, the reconstruction algorithm can process readings from multiple sensors to accurately calculate the voltage and current flowing through each wire. As a non-contact method, this invention can be easily installed in pre-existing systems and can be calibrated without interrupting services. Furthermore, this invention can monitor any device that produces a magnetic field and is, therefore, not limited to measuring electrical current and voltages. When coupled with water flow meters, which often use permanent magnets to couple gears inside and outside the water pipe, this technology can measure water flow by tracking the permanent magnet's rotation. This provides a quick and easy way to add functionality, such as wireless communication, to existing flow meters.

Advantages

  • Non-contact monitoring of magnetic fields
  • Can give a wide variety of real-time data, such as electrical current, voltage, and water flow
  • Easy installation on existing systems while they are running