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US 8,134,346 B1Granted
System and method for power factor correction
AssigneeEcoEarthEnergy, Inc.
InventorsHenry N. Huta, Stephen R. Phillips, Robert E. Morgan
Life of this patent
Estimating the term…
Abstract
A system and method for dynamically adjusting capacitance added in parallel to an electrical line input for improving efficiency of an electrical system. A microprocessor monitors in real time the current and voltage wave forms of a system and selects the optimum amount of capacitance from a bank of capacitors of different values. The system is implemented at the watt-hour meter to encourage adoption of the device by utility companies and customers.
Claims17
A power factor correction system, comprising:
- a power factor correction controller, the power factor correction controller comprising:
- a capacitor bank, comprising a plurality of capacitors;
- and
- a power factor correction circuit coupled to the capacitor bank for determining an existing power factor of a load and for selectively coupling one or more of the plurality of capacitors in parallel with the load to adjust the power factor towards unity, the power factor correction circuit comprising:
- a signal conditioning circuit coupled across a first and second alternating current incoming power lines, the signal monitoring circuit to sense a voltage signal supplied to a load by the first and second alternating current power lines and to sense a load current signal drawn by the load;
- an analog to digital conversion circuit coupled to the signal monitoring circuit, the analog to digital conversion circuit to receive the sensed voltage signal and the sensed current signal and to generate a digital pulse representative of the zero-crossing of the voltage signal and the current signal;
- a digital signal processing and communications circuit coupled to the analog to digital conversion circuit, the digital signal processing and communications circuit to receive the digital pulse representative of the zero-crossing of the voltage signal and the current signal, to determine a phase angle representative of an existing power factor of the load and to compare the existing power factor of the load to a preset threshold phase angle to determine if the existing power factor is leading or lagging;
- and
- a capacitor switching circuit coupled to the digital signal processing and communications circuit and to the capacitor bank, the capacitor switching circuit to selectively couple one or more of the plurality of capacitors in the capacitor bank to be in parallel with the load to adjust the power factor of the load towards unity;
- and
- a watt-hour meter adapter electrically coupled to the power factor correction controller.
8 more elements
A method for correcting a power factor of a load circuit, the method comprising:
- positioning a watt-hour meter adapter between an existing watt-hour meter socket and a watt-hour meter, the watt-hour meter adapter electrically coupled to a power factor correction controller;
- sensing the power supply voltage signal at the watt-hour meter;
- sensing the load current signal;
- determining the existing power factor of the load from the sensed power supply voltage signal and the sensed load current signal, wherein determining the existing power factor of the load comprises:
- identifying the zero-crossing of the sensed voltage signal to generate a digital pulse representative of the zero-crossing of the voltage signal;
- identifying the zero-crossing of the sensed load current signal to generate a digital pulse representative of the zero-crossing of the load current signal;
- determining a time delay between the voltage signal and the current signal by comparing the digital pulse representative of the zero-crossing of the voltage signal to the digital pulse representative of the zero-crossing of the load current signal;
- converting the time delay to a phase angle representative of the existing power factor of the load;
- and
- comparing the phase angle to a preset threshold phase angle to determine if the existing power factor is leading or lagging;
- and
- selectively coupling or decoupling capacitors in parallel with the load circuit to correct the power factor of the load circuit to approximately unity.
9 more elements
Dependencies are inferred from the claim text.