Power factor improving arrangement
AssigneeAT&T Corp.
InventorsRichard W. Glaser, James L. McIntosh
Life of this patent
Estimating the term…
Abstract
An impedance compensator for adjusting the power factor of a power distribution system by directly measuring impedance at a point in the power distribution system and dynamically adjusting that impedance to be resistive yielding a power factor of one. The compensator dynamically inserts and removes both capacitance and inductance to adjust the impedance. The inductance is utilized to make coarse adjustments to the impedance, whereas the capacitance is utilized to make fine adjustments.
Claims17
Apparatus for adjusting a power factor in a power distribution system, comprising:
- means for continuously determining an impedance of said power distribution system;
- means for convening said impedance of said power distribution system to a voltage representing said impedance;
- means responsive to said voltage for indicating whether said impedance is capacitive, inductive, or resistive;
- means for controlling an amount of capacitance in parallel with said power distribution system to adjust said impedance to be substantially resistive resulting in said power factor being substantially unity with said capacitance having a predetermined maximum and minimum values;
- and
- means for controlling an amount of inductance in series with said power distribution system to adjust said impedance to be substantially resistive resulting in said power factor being substantially unity upon said predetermined maximum or minimum values of capacitance having been exceeded.
Apparatus for adjusting a power factor in a power distribution system, comprising:
- means for continuously determining an impedance of said power distribution system;
- a transformer for reflecting said impedance;
- an oscillator responsive to said reflected impedance for generating a frequency representing said impedance;
- a frequency-to-voltage converter responsive to said frequency for generating said voltage;
- means responsive to said voltage for indicating whether said impedance is capacitive, inductive, or resistive;
- and
- means for adjusting said impedance to be substantially resistive resulting in said power factor being substantially unity.
The apparatus of clam 4 wherein said indicating means comprises an error amplifier responsive to said voltage for generating an error voltage such that said error voltage is substantially equal to a predetermined center voltage upon said impedance being resistive and said error voltage being shifted to a first voltage range from said predetermined center voltage upon said impedance being capacitive and said error voltage being shifted to a second voltage range from said predetermined center voltage upon said impedance being inductive.
A method for adjusting a power factor in a power distribution system, said method comprising the steps of:
- continuously determining an impedance of said power distribution system;
- converting said impedance of said power distribution system to a voltage representing said impedance;
- indicating in response to said voltage whether said impedance is capacitive, inductive, or resistive;
- controlling an amount of capacitance in parallel with said power distribution system to adjust said impedance to be substantially resistive resulting in said power factor being substantially unity with said capacitance having a predetermined maximum and minimum values;
- and
- controlling an amount of inductance in series with said power distribution system to adjust said impedance to be substantially resistive resulting in said power factor being substantially unity upon said predetermined maximum or minimum values of capacitance having been exceeded.
A method for adjusting a power factor in a power distribution system, said method comprising the steps of:
- continuously determining an impedance of said power distribution system;
- reflecting said impedance with a transformer;
- generating a frequency representing said impedance by an oscillator responsive to said reflected impedance;
- generating said voltage by a frequency-to-voltage converter responsive to said frequency;
- indicating in response to said voltage whether said impedance is capacitive, inductive, or resistive;
- and
- adjusting said impedance to be substantially resistive resulting in said power factor being substantially unity.
Dependencies are inferred from the claim text.