High speed power factor controller

Claim 2

A power factor correcting system, comprising: a voltage sensor having an input coupled across first and second alternating current power lines; a current sensor having an input coupled to one of said first and second power lines; a digital microprocessor; circuitry for coupling signals from said voltage sensor to said microprocessor; circuitry for coupling signals from said current sensor to said microprocessor; said microprocessor including programming means for determining a phase difference between a sensed voltage and a sensed current; incrementally adjustable power factor correction circuitry absorbing current from said power line during a portion of each cycle of the alternating current and for supplying current to said power line during another portion of said cycle of the alternating current; switching circuitry including a plurality of switching devices, coupling said power factor correction circuitry to said power line; said microprocessor being coupled to said switching circuitry to change the state of said switching devices to change the power factor of said system toward unity; said microprocessor supplying updated switching signals to said switching circuitry at least several times each second; and said power factor correction circuitry being a capacitive network, including a plurality of capacitors, and said switching devices selectively coupling said capacitors to the power line; and wherein said capacitive network is a binary ladder network.

Claim 3

A system as defined in claim 1, wherein said microprocessor supplies updated switching outputs to said switching circuitry at least 5 times per second.

Claim 4

A power factor correction system comprising: a voltage sensor having an input coupled across a first and second alternating current power lines; a current sensor having an input coupled to one of said first and second power lines; a digital microprocessor; circuitry for coupling signals from said voltage sensor to said microprocessor; circuitry for coupling signals from said current sensor to said microprocessor: said microprocessor including programming means for determining a phase difference between a sensed voltage and a sensed current; incrementally adjustable power factor correction circuitry absorbing current from said power line during a portion of each cycle of the alternating current and for supplying current to said power line during another portion of said cycle of the alternating current; switching circuitry including a plurality of switching devices, coupling said power factor correction circuitry to said power line; said microprocessor being coupled to said switching circuitry to change the state of said switching devices to change the power factor of said system toward unity; said microprocessor supplying updated switching signals to said switching circuitry at least several times each second; and said microprocessor further including first, second, third and fourth switching outputs responsive to said phase difference for applying said outputs to said switching circuitry.

Claim 5

A power factor correction system comprising: a voltage sensor having an input coupled across a first and second alternating current power lines; a current sensor having an input coupled to one of said first and second power lines; a digital microprocessor; circuitry for coupling signals from said voltage sensor to said microprocessor; circuitry for coupling signals from said current sensor to said microprocessor: said microprocessor including programming means for determining a phase difference between a sensed voltage and a sensed current; incrementally adjustable power factor correction circuitry absorbing current from said power line during a portion of each cycle of the alternating current and for supplying current to said power line during another portion of said cycle of the alternating current; switching circuitry including a plurality of switching devices, coupling said power factor correction circuitry to said power line; said microprocessor being coupled to said switching circuitry to change the state of said switching devices to change the power factor of said system toward unity; said microprocessor supplying updated switching signals to said switching circuitry at least several times each second; and said microprocessor further including first, second, third and fourth switching outputs responsive to said phase difference for applying said outputs to said switching circuitry.

Claim 6

A system as defined in claim 3, wherein said power factor correction circuitry is a capacitive network, including a plurality of capacitors, and said plurality of switching devices selectively couple individual ones of said plurality of capacitors to the power line.

Claim 7

A system as defined in claim 3, wherein said capacitive network is a binary ladder network.

Claim 8

A system as defined in claim 3, wherein said microprocessor supplies updated switching outputs to said switching circuitry at least 5 times per second.

Claim 9

A system as defined in claim 3, wherein said microprocessor supplies updated switching outputs to said switching circuitry at least 10 times per second.

Claim 10

A system as defined in claim 3, wherein said circuitry for coupling signals from said voltage sensor and said circuitry for coupling signals from said current sensor each includes a set of low pass filters coupled between said current and voltage sensors respectively and said microprocessor.

Claim 11

A system as defined in claim 3, wherein said circuitry for coupling signals from said voltage sensors and said circuitry for coupling signals from said current sensor include: analog-to-digital conversion circuitry for converting the output from said current and voltage sensors to a digital form to supply to said microprocessor.

Claim 12

A power factor correction system as defined in claim 3, wherein said incrementally adjustable power factor correction circuitry includes: a transformer having a first winding and a second winding; a plurality of capacitors; and wherein said plurality of switching devices includes: a first plurality of switching devices responsive to switching pluses from said microprocessor coupling said capacitors across said second winding; a second plurality of switching devices responsive to switching pluses from said microprocessor, coupling said first winding across said first and second power lines; and means for correcting the power factor associated with said power lines by switching energy between magnetic and electric fields in said capacitors and said windings.

Claim 13

A system as defined in claim 2, wherein said incrementally adjustable power factor correction circuitry includes: a transformer having a first winding and a second winding; and a first and second capacitor; and wherein said plurality of switching devices includes: a first switching device having an input coupled to the first switching output and having an output coupled in series with said first winding forming a first switching path, said first switching path being disposed across said power lines; a second switching device having an input coupled to the second switching output and having an output coupled in series with said first winding forming a second switching path, said second switching path being disposed across said power lines; a third switching device having an input coupled to the third switching output and having an output coupled in series with said first capacitor and said second winding forming a third switching path; and a fourth switching device having an input coupled to the fourth switching output coupled and having an output coupled in series with said second capacitor and said second winding forming a fourth switching path; wherein a power factor associated with said first and second power lines is corrected by selectively switching energy between magnetic and electric forms in said capacitors and said windings.

Claim 14

A power factor correction system, comprising: a load having a variable reactive impedance; a source of alternating current (AC) power; alternating current power lines coupling said source of AC power to said load; a voltage sensor having an input coupled to said AC power lines; a current sensor having an input coupled to said AC power lines; a digital microprocessor; circuitry for coupling signals from said voltage sensor to said microprocessor; circuitry for coupling signals from said current sensor to said microprocessor; said microprocessor including programming means for determining a phase difference between a sensed voltage and a sensed current; incrementally adjustable power factor correction circuitry absorbing current from one of said power lines during a portion of each cycle of the alternating current and for supplying current to one of said power lines during another portion of said cycle of the alternating current; switching circuitry including a plurality of switching devices, coupling said power factor correction circuitry to said power lines; said microprocessor being coupled to said switching circuitry to change the state of said switching devices to change the power factor of said system toward unity; said microprocessor supplying updated switching signals to said switching circuitry at least once each second; and wherein said power factor correction circuitry is a capacitive network, including a plurality of capacitors, and said switching devices selectively couple said capacitors to the power line.

Claim 15

A power factor correction system, comprising: a load having a variable reactive impedance; a source of alternating current (AC) power; alternating current power lines coupling said source of AC power to said load; a voltage sensor having an input coupled to said AC power lines; a current sensor having an input coupled to said AC power lines; a digital microprocessor; circuitry for coupling signals from said voltage sensor to said microprocessor; circuitry for coupling signals from said current sensor to said microprocessor; said microprocessor including programming means for determining a phase difference between a sensed voltage and a sensed current; incrementally adjustable power factor correction circuitry absorbing current from one of said power lines during a portion of each cycle of the alternating current and for supplying current to one of said power lines during another portion of said cycle of the alternating current; switching circuitry including a plurality of switching devices, coupling said power factor correction circuitry to said power lines; said microprocessor being coupled to said switching circuitry to change the state of said switching devices to change the power factor of said system toward unity; said microprocessor supplying updated switching signals to said switching circuitry at least once each second; and wherein said power factor correction circuitry is a capacitive network, including a plurality of capacitors, and said switching devices selectively couple said capacitors to the power line.

Claim 16

A system as defined in claim 12, wherein said capacitive network is a binary ladder network.

Claim 17

A system as defined in claim 12, wherein said microprocessor supplies updated switching outputs to said switching circuitry at least 5 times per second.

Claim 18

A system as defined in claim 12, wherein said circuitry for coupling signals from said voltage sensors and said circuitry for coupling signals from said current sensor include: low pass filters coupled between said current and voltage sensors and said microprocessor.

Claim 19

A system as defined in claim 12, wherein said circuitry for coupling signals from said voltage sensors and said circuitry for coupling signals from said current sensor include: analog-to-digital conversion circuitry for converting the output from said current and voltage sensors to digital form to supply to said microprocessor.

Claim 24

An apparatus according to claim 18, wherein said programmable means causes said switching means to release said current charge to form a current waveform congruently matched against the cyclic period of the phase line current.

Claim 25

An apparatus according to claim 18, wherein said phase line current and said phase line voltage is multi-phase.

Claim 26

An apparatus according to claim 18, wherein said phase line current and said phase line voltage is three phase.

Claim 27

An apparatus according to claim 18, wherein said phase line current and said phase line voltage is single phase.

Claim 28

An apparatus according to claim 18, wherein said phase line current and said phase line voltage is two phase.