Citation
Brad Campbell, Prabal Dutta. "Gemini: A Non-Invasive, Energy-Harvesting True Power Meter". Real-Time Systems Symposium (RTSS'14), IEEE, 2, December, 2014.

Abstract
Power meters are critical for submetering loads in residential and commercial settings, but high installation cost and complexity hamper their broader adoption. Recent approaches address installation burdens by proposing non-invasive meters that easily clip onto a wire, or stick onto a circuit breaker, to perform contactless metering. Unfortunately, these designs require regular maintenance (e.g. battery replacement) or reduce measurement accuracy (e.g. work poorly with non-unity power factors). This paper presents Gemini, a new design point in the power metering space. Gemini addresses the drawbacks of prior approaches by decoupling and distributing the AC voltage and current measurement acquisitions, and recombining them wirelessly using a low-bandwidth approach, to offer non-invasive real, reactive, and apparent power metering. Battery maintenance is eliminated by using an energy-harvesting design that enables the meter to power itself using a current transformer. Accuracy is substantially improved over other non-invasive meters by virtualizing the voltage channel-- effectively allowing the meter to calculate power as if it could directly measure voltage (since true power requires sample-by-sample multiplication of current and voltage measurements acquired with tight timing constraints). Collectively, these improvements result in a new design point that meters resistive loads with 0.6 W average error and a range of reactive and switching loads with 2.2 W average error-- matching commercial, mains-powered solutions.

Electronic downloads

• https://www.src.org/library/publication/p070880/%20. (Link to paper on SRC website.)
• http://web.eecs.umich.edu/~prabal/pubs/papers/campbell14gemini.pdf

• HTML

  Brad Campbell, Prabal Dutta. <a
  href="http://www.terraswarm.org/pubs/329.html"
  >Gemini: A Non-Invasive, Energy-Harvesting True Power
  Meter</a>, Real-Time Systems Symposium (RTSS'14),
  IEEE, 2, December, 2014.

• Plain text

  Brad Campbell, Prabal Dutta. "Gemini: A Non-Invasive,
  Energy-Harvesting True Power Meter". Real-Time Systems
  Symposium (RTSS'14), IEEE, 2, December, 2014.

• BibTeX

  @inproceedings{CampbellDutta14_GeminiNonInvasiveEnergyHarvestingTruePowerMeter,
      author = {Brad Campbell and Prabal Dutta},
      title = {Gemini: A Non-Invasive, Energy-Harvesting True
                Power Meter},
      booktitle = {Real-Time Systems Symposium (RTSS'14)},
      organization = {IEEE},
      day = {2},
      month = {December},
      year = {2014},
      abstract = {Power meters are critical for submetering loads in
                residential and commercial settings, but high
                installation cost and complexity hamper their
                broader adoption. Recent approaches address
                installation burdens by proposing non-invasive
                meters that easily clip onto a wire, or stick onto
                a circuit breaker, to perform contactless
                metering. Unfortunately, these designs require
                regular maintenance (e.g. battery replacement) or
                reduce measurement accuracy (e.g. work poorly with
                non-unity power factors). This paper presents
                Gemini, a new design point in the power metering
                space. Gemini addresses the drawbacks of prior
                approaches by decoupling and distributing the AC
                voltage and current measurement acquisitions, and
                recombining them wirelessly using a low-bandwidth
                approach, to offer non-invasive real, reactive,
                and apparent power metering. Battery maintenance
                is eliminated by using an energy-harvesting design
                that enables the meter to power itself using a
                current transformer. Accuracy is substantially
                improved over other non-invasive meters by
                virtualizing the voltage channel-- effectively
                allowing the meter to calculate power as if it
                could directly measure voltage (since true power
                requires sample-by-sample multiplication of
                current and voltage measurements acquired with
                tight timing constraints). Collectively, these
                improvements result in a new design point that
                meters resistive loads with 0.6 W average error
                and a range of reactive and switching loads with
                2.2 W average error-- matching commercial,
                mains-powered solutions. },
      URL = {http://terraswarm.org/pubs/329.html}
  }
  

Posted by Barb Hoversten on 30 Jun 2014.