Power factor correction by measurement and removal of overtones
First Claim
1. A circuit responsive to an input power supply signal at an input supply voltage that varies largely sinusoidally with time at a fundamental supply frequency, the input supply signal being at an input supply current susceptible of having at least one overtone of the fundamental supply frequency, the circuit comprising regulator/control circuitry for measuring at least one such overtone individually in the input supply current, or in a rectified form of the input supply current, and for operating on the input supply current or on its rectified form to largely remove each individually measured overtone.
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Accused Products
Abstract
A power factor correction circuit (42/44) responsive to an input power supply signal at an input supply voltage (VAC) that varies largely sinusoidally with time at a fundamental supply frequency contains regulator/control circuitry (60, 62, and 64) for measuring and removing overtones (ILDm or IFWRm) in the input supply current (ILD) or in a rectified form (IFWR) of the input supply current. Each overtone is expressible as the product of an amplitude component (Im) and a sinusoidal function (Im sin [(m+1)ωACt]) that varies with time at an integer multiple of the fundamental supply frequency. The regulator/control circuitry measures an overtone by determining the overtone'"'"'s amplitude component. After generating an adjustment factor (SADJ) largely as the product of that overtone'"'"'s amplitude component and an associated sinusoidal function, the regulator/control circuitry adjusts the input supply current or its rectified form by an amount corresponding to the adjustment factor for each measured overtone.
22 Citations
24 Claims
- 1. A circuit responsive to an input power supply signal at an input supply voltage that varies largely sinusoidally with time at a fundamental supply frequency, the input supply signal being at an input supply current susceptible of having at least one overtone of the fundamental supply frequency, the circuit comprising regulator/control circuitry for measuring at least one such overtone individually in the input supply current, or in a rectified form of the input supply current, and for operating on the input supply current or on its rectified form to largely remove each individually measured overtone.
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5. A circuit responsive to an input power supply signal at an input supply voltage that varies largely with time at a supply frequency, the circuit comprising:
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rectifier circuitry for largely performing full-wave rectification on the input supply signal to produce a full-wave rectified supply signal at a full-wave rectified voltage and a full-wave rectified current susceptible of having at least one overtone of the fundamental supply frequency; a regulator for regulating the full-wave rectified voltage to produce a regulated power supply voltage with reduced voltage ripple; and control circuitry for measuring at least one such overtone individually in the full-wave rectified current and for providing the regulator with a primary control signal that causes at least one such individually measured overtone to be largely removed from the full-wave rectified current such that it largely tracks the full-wave rectified voltage in time-varying waveform. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of performing power factor correction on an input power supply signal at an input supply voltage that varies largely sinusoidally with time at a fundamental supply frequency, the input supply signal being at an input supply current susceptible of having at least one overtone of the fundamental supply frequency, the method comprising:
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measuring at least one such overtone individually in the input supply current; and operating on the input supply current to largely remove each individually measured overtone. - View Dependent Claims (20, 21, 22)
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23. A method of performing power factor correction on an input power supply signal at an input supply voltage that varies largely sinusoidally with time at a fundamental supply frequency, the method comprising:
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largely performing full-wave rectification on the input supply signal to produce a full-wave rectified signal at a full-wave rectified voltage and a full-wave rectified current susceptible of having at least one overtone of the fundamental supply frequency; regulating the full-wave rectified signal to produce a regulated power supply signal with reduced voltage ripple; measuring at least one such overtone individually in the full-wave rectified current; and providing a primary control signal that causes at least one such individually measured overtone to be largely removed from the full-wave rectified current such that it largely tracks the full-wave rectified voltage in time-varying waveform. - View Dependent Claims (24)
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Specification