Self-powered wireless energy sensor for efficient building management

Abstract

A sensor for measuring current flow includes a housing containing a power generation circuit and a current measurement circuit. The sensor is entirely self-contained and is non-invasively attachable to a conductor. The sensor is self-powered using energy harvested by the power generation circuit. The current measurement circuit allows for continuous, uninterrupted measurement of at least one property related to the flow of current through the conductor. The sensor wirelessly transmits data related to the measured current flow to a computing device. The sensor may be used with other similar sensors to form a wireless sensor network that monitors one or more properties related to the flow of current through one or more conductors within a system.

What is claimed is: 
     
         1 . A sensor configured to measure a property related to a flow of current through a conductor, the sensor comprising:
 a housing comprising:
 a base portion; and 
 an upper portion configured to move relative to the base portion between an open housing configuration in which the upper portion is at least partially detached from the base portion and a closed housing configuration in which the upper portion is at least partially attached to the base portion, 
 wherein, in the closed housing configuration, the base portion and upper portion define a housing interior, a first opening into the housing interior through a first portion of the housing, a second opening into the housing interior through a second portion of the housing opposite the first portion of the housing, and a passageway extending through the housing interior between the first opening and the second opening; 
   an energy harvesting element comprising:
 a harvesting element lower portion fixed to the base portion of the housing; and 
 a harvesting element upper portion fixed to the upper portion of the housing; 
 wherein, in the closed housing configuration, a first end of the harvesting element lower portion contacts a first end of the harvesting element upper portion and a second end of the harvesting element lower portion contacts a second end of the harvesting element upper portion to form a closed structure around the passageway; and 
   a sensing element comprising:
 a sensing element lower portion fixed to the base portion of the housing; and 
 a sensing element upper portion fixed to the upper portion of the housing; 
 wherein, in the closed housing configuration, a first end of the sensing element lower portion contacts a first end of the sensing element upper portion and a second end of the sensing element lower portion is positioned opposite and spaced apart from a second end of the sensing element upper portion to define a space therebetween. 
   
     
     
         2 . The sensor of  claim 1 , wherein each of the harvesting element upper portion and the harvesting element lower portion are formed of a magnetic material. 
     
     
         3 . The sensor of  claim 2 , the harvesting element further comprising a winding formed about at least one of the harvesting element upper portion and the harvesting element lower portion. 
     
     
         4 . The sensor of  claim 3 , further comprising an energy harvesting circuit disposed within one of the housing upper portion and the housing base portion, the energy harvesting circuit configured to harvest energy from a current induced in the winding in response to a flow of current through a conductor to which the sensor is attached. 
     
     
         5 . The sensor of  claim 1 , wherein the energy harvesting element is configured to harvest energy at a same time that the sensing element is used to measure at least one property related to the flow of current through a conductor to which the sensor is attached. 
     
     
         6 . The sensor of  claim 1 , further comprising a supercapacitor configured to store energy harvested by the harvesting element. 
     
     
         7 . The sensor of  claim 1 , wherein each of the sensing element upper portion and the sensing element lower portion are formed of a magnetically permeable material. 
     
     
         8 . The sensor of  claim 7 , wherein the sensing element further comprises a Hall effect device supported by one of the base portion of the housing or the upper portion of the housing such that, in the closed housing configuration, the Hall effect device is disposed within the space between the second end of the sensing element lower portion and the second end of the sensing element upper portion. 
     
     
         9 . The sensor of  claim 8 , further comprising a microprocessor configured to receive readings from the Hall effect device and determine a measurement of at least one property related to the flow of current through a conductor to which the sensor is attached. 
     
     
         10 . The sensor of  claim 1 , wherein, in the closed housing configuration, each of the passageway through the housing interior, an opening defined by the harvesting element lower portion and harvesting element upper portion, and an opening defined by the sensing element lower portion and the sensing element upper portion are centered about a common axis. 
     
     
         11 . The sensor of  claim 1 , wherein the upper portion of the housing and the base portion of the housing are hingedly attached. 
     
     
         12 . A monitoring system comprising:
 a computing device; and   a sensor comprising:
 a sensing element configured to measure at least one property related to a flow of current through a conductor; 
 an energy harvesting element configured to harvest energy in response to the flow of current through the conductor, the energy harvesting element being discrete and separate from the sensing element; 
 a networking element configured to wirelessly transmit data from the sensing element to the computing device; and 
 a housing having an interior within which each of the energy harvesting element, sensing element and networking element are contained; 
 wherein the energy harvesting element and sensing element are arranged within the housing such that, when the sensor is attached to the conductor, the conductor passes through the interior of the housing, through an opening defined by the energy harvesting element, and through an opening defined by the sensing element. 
   
     
     
         13 . The monitoring system of  claim 12 , wherein the sensing element is configured to continuously and uninterruptedly measure the least one property related to the flow of current through the conductor 
     
     
         14 . The monitoring system of  claim 12 , wherein the sensor is powered exclusively by energy harvested using the energy harvesting element. 
     
     
         15 . The monitoring system of  claim 12 , wherein the conductor includes a first end attached to a first substrate and a second end attached to a second substrate, the sensor configured to be attached to the conductor without requiring either the first end of the conductor or the second end of the conductor to be disconnected. 
     
     
         16 . The monitoring system of  claim 12 , wherein the sensor comprises a plurality of sensors, each of the sensors being configured to communicate with at least one of another sensor and the computing device. 
     
     
         17 . The monitoring system of  claim 12 , wherein the computing device is a gateway configured to transmit the data received from the networking element to a control system computing device. 
     
     
         18 . A method comprising:
 providing a sensor comprising:
 a sensing element; 
 an energy harvesting element discrete and separate from the sensing element; 
 a networking element; and 
 a housing having an interior within which each of the energy harvesting element, sensing element and networking element are contained; 
   non-invasively attaching the sensor to a conductor, wherein when the sensor is attached to the conductor, the conductor passes through the interior of the housing, through an opening defined by the energy harvesting element, and through an opening defined by the sensing element;   harvesting energy from a flow of current through the conductor using the harvesting element;   powering the sensing element using energy harvested by the harvesting element;   while the harvesting element is harvesting energy, measuring at least one property related to the flow of current through the conductor using the sensing element;   powering the networking element using energy harvested by the harvesting element; and   transmitting data based on the at least one property measured by the sensing element to a computing device using the networking element.   
     
     
         19 . The method of  claim 18 , wherein the housing is defined by an upper portion and a base portion, and wherein attaching the sensor to the conductor comprises:
 at least partially detaching the upper portion from base portion;   positioning the conductor in a space defined between the upper portion and the base portion when the upper portion is at least partially detached from the base portion; and   reattaching the upper portion and the base portion.   
     
     
         20 . The method of  claim 18 , further comprising:
 generating, by the computing device, one or more signals in response to the computing device receiving the data from the networking element;   using the one or more signals to at least one of:
 generate and transmit an alert to a user device; or 
 modify an operation of a device to which the conductor is operably coupled.