Digital power consumption meter for displaying instantaneous and consumed electric power of an electrical device

• US 5,869,960 A
• Filed: 12/19/1996
• Issued: 02/09/1999
• Est. Priority Date: 12/19/1996
• Status: Expired due to Fees

• Current Assignee: Ethan Brand
• Original Assignee: Ethan Brand
• Inventors: Brand, Ethan
• Primary Examiner(s): BROCK, MICHAEL J
• Application Number:
  US08/770,718
• Time in Patent Office: 782 Days
• Field of Search: 324/141, 324/142, 324/129, 324/127
• US Class Current: 324/142
• CPC Class Codes: G01D 2204/18 Remote displaying of utility meter readings
• CPC Class Codes: G01D 4/002 Remote reading of utility meters
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 22/00 Arrangements for measuring time integral of electric power or current, e.g. electricity meters
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/242 Home appliances
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

A portable power meter is provided for measuring and displaying the real instantaneous power and consumed power of a portable or permanently mounted electrical device. The power meter (10) is provided which can plug into a electric wall socket and is provided with its own socket (14) for receiving the plug of an electrical device. In alternative embodiments, the power meter can be configured to monitor electrical devices which are permanently wired.

Claims

1. An electric power consumption meter circuit for measuring real and consumed power of an electrical load, comprising:

means for connecting the load to a power source which provides a load supply voltage and including a load current sensing resistor connected between the load and the power source, the load current through the resistor resulting in a load current induced voltage;

a FET arranged as an electronic switch and connected through a current limiter resistor to the load current sensing resistor to sink the load current induced voltage when switched on;

an adjustable phase shift circuit connected to produce a 90 degree phase delayed voltage wave form of the load supply voltage;

an open loop comparator connected to the phase shift circuit to provide a square wave output of the delayed voltage wave form to the gate of the FET to provide switching thereof;

an amplifier connected to the current limiter resistor and the FET to produce an amplified output signal;

a voltage peak detector connected to the amplifier to detect the peak voltage of the amplifier output signal;

a voltmeter calibrated in power units for displaying the real power as a function of the peak voltage;

a voltage to frequency convertor for converting the peak voltage to a frequency signal;

a counter calibrated in power consumption units for counting the frequency signal and displaying the total consumed power.