US5099407A — Inverter with power factor correction circuit

Claim 1

Independent Claim 165 words

An inverter circuit including circuitry components adapted to perform various functions, said circuitry including: means for receiving an AC power input; means for modifying said AC power received to a high frequency AC output supplied to a load; means for storing a DC voltage; means for providing power factor correction for the circuit by feeding back a portion of the high frequency AC output as a DC output voltage to said means for storing said DC voltage via a current limiting inductor and a DC blocking capacitor; means for taking said stored DC voltage and providing same through a series of devices to a power unit and modifying the input in respect of a load placed upon said power unit; said circuit further including means for sensing when the load is missing and allowing said power unit to remain in a standby mode of operation until a load is sensed; and further including means for selectively controlling the amount of power available to the load.

Claim 2

Dependent Claim 165 words

An inverter circuit including circuitry components adapted to perform various functions, said circuitry including: means for receiving an AC power input; means for modifying said AC power received to a high frequency AC output supplied to a load; means for storing a DC voltage; means for providing power factor correction for the circuit by feeding back a portion of the high frequency AC output as a DC output voltage to said means for storing said DC voltage via a current limiting inductor and a DC blocking capacitor; means for taking said stored DC voltage and providing same through a series of devices to a power unit and modifying the input in respect of a load placed upon said power unit; said circuit further including means for sensing when the load is missing and allowing said power unit to remain in a standby mode of operation until a load is sensed; and further including means for selectively controlling the amount of power available to the load.

Claim 3

Dependent Claim 25 words

The circuit of claim 1 wherein said means for modifying said AC power received to a high frequency AC output comprise a resonant oscillator/inverter circuit.

Claim 4

Dependent Claim 14 words

The circuit of claim 2 wherein said oscillator/inverter circuit includes at least one transformer.

Claim 5

Dependent Claim 28 words

The circuit of claim 3 wherein said means for selectively controlling the amount of power available to the load comprises a dimming circuit which includes a variable resistor.

Claim 6

Dependent Claim 30 words

The circuit of claim 4 wherein said variable resistor controls the voltage on a capacitor in series with a saturating transformer, which voltage controls the frequency of said oscillator/inverter circuit.

Claim 7

Dependent Claim 32 words

The circuit of claim 5 wherein windings and material saturation flux density of the transformer are chosen so the transformer saturates after a predetermined period of time relative to the oscillator frequency.

Claim 8

Dependent Claim 25 words

The circuit of claim 6 further including a step up or a step down transformer between the source of high frequency voltage and the load.

Claim 9

Dependent Claim 25 words

The circuit of claim 7 wherein the inductance of a primary winding of the transformer is set to mirror the voltage of the inverter load.

Claim 10

Dependent Claim 10 words

The circuit of claim 8 including an H bridge converter.

Claim 11

Dependent Claim 26 words

The circuit of claim 9 wherein said H bridge converter comprises two bypass capacitors forming one leg thereof and two transistors forming the other leg thereof.

Claim 12

Dependent Claim 18 words

The circuit of claim 10 including a resonant tank comprising a transformer primary, a capacitor and an inductor.

Claim 13

Dependent Claim 26 words

The circuit of claim 11 wherein a center tap is provided between said bypass capacitors which forms an AC current bypass path from said resonant tank.

Claim 14

Dependent Claim 22 words

The circuit of claim 12 wherein said AC bypass path is centered between an absolute maximum and absolute minimum power supply voltage.

Claim 15

Dependent Claim 23 words

The circuit of claim 13 wherein said capacitor of said AC bypass path creates a blockage against DC power attempting to pass therethrough.

Claim 16

Dependent Claim 23 words

The circuit of claim 14 wherein said power capacitors are discharged when the input power level falls below that stored in the capacitors.

Claim 17

Dependent Claim 18 words

The circuit of claim 15 including a transformer which determines the frequency of oscillation of the oscillator/inverter circuit.

Claim 18

Dependent Claim 14 words

The circuit of claim 16 wherein said transformer is realized by a saturable inductor.

Claim 19

Dependent Claim 30 words

The circuit of claim 17 wherein the output from said transformer is directed through a series connected inductor and DC blocking capacitor, creating a frequency changing effect within the circuit.

Claim 20

Dependent Claim 15 words

The circuit of claim 18 wherein a starting circuit is provided for the oscillator/inverter circuit.

Claim 21

Dependent Claim 13 words

The circuit of claim 19 wherein said starting circuit includes a triggering device.

Claim 22

Dependent Claim 14 words

The circuit of claim 20 wherein said triggering device comprises a bidirectional trigger diode.

Claim 23

Dependent Claim 18 words

The circuit of claim 21 including means for disabling said trigger diode once said oscillator/inverter circuit is started.

Claim 24

Dependent Claim 24 words

The circuit of claim 22 wherein said oscillator/inverter circuit includes two transistors which are driven by said transformer in an alternating mode of operation.

Claim 25

Dependent Claim 17 words

The circuit of claim 23 wherein said alternating mode of operation is triggered by zero voltage crossings.

Claim 26

Dependent Claim 17 words

The circuit of claim 24 wherein said transistors alternately turn on into zero voltage at each crossing.

Claim 27

Dependent Claim 15 words

The circuit of claim 25 including means for controlling the voltage attained by said transformer.

Claim 28

Dependent Claim 22 words

The circuit of claim 24 wherein the resonant frequency is chosen to be slightly lower than the driving frequency for the transformer.

Claim 29

Dependent Claim 9 words

The circuit of claim 27 including a secondary transformer.

Claim 30

Dependent Claim 18 words

The circuit of claim 28 wherein said resonant tank is provided by the primary of the secondary transformer.

Claim 31

Dependent Claim 26 words

The circuit of claim 29 wherein a load is presented to the secondary transformer by an inductor placed in series with the primary of the transformer.

Claim 32

Dependent Claim 29 words

The circuit of claim 30 wherein two diodes are tapped into the primary of the secondary transformer for clamping voltage away to just prior to starting of the load.

Claim 33

Dependent Claim 25 words

The circuit of claim 31 wherein power generated by the first transformer is fed to and stored in the resonant tank of the secondary transformer.

Claim 34

Dependent Claim 9 words

The circuit of claim 32 including shutdown protection means.

Claim 35

Dependent Claim 38 words

The circuit of claim 33 wherein said shutdown protection means include a Zener diode, the breakdown voltage of which is chosen to mirror the voltage on the sense winding of the secondary transformer when the load is present.

Claim 36

Dependent Claim 41 words

The circuit of claim 34 wherein said Zener diode controls the function of a transistor which in turn controls operation of the oscillator/inverter circuit, such that, upon de-energization of the transistor, the oscillator/inverter circuit enters a quiescent, standby mode of operation.

Claim 37

Dependent Claim 15 words

The circuit of claim 35 wherein said transistor controls both sides of the oscillator/inverter circuit.

Claim 38

Dependent Claim 24 words

The circuit of claim 36 wherein said transistor is de-energized upon the sensing of a load present at the output of the secondary transformer.

Claim 39

Dependent Claim 28 words

The circuit of claim 36 wherein a fixed ratio may be set between the inductance on the primary of the first transformer of that of the secondary transformer.

Claim 40

Dependent Claim 153 words

An inverter circuit including circuitry components for performing various functions, said circuitry including: means for receiving an AC power input; means for modifying said AC power received to a high frequency AC output supplied to a load; means for storing a DC voltage; means for providing power factor correction for the circuit by feeding back a portion of the high frequency AC output as a DC output voltage to said means for storing said DC voltage via a current limiting inductor and a DC blocking capacitor; means for taking said stored DC voltage and providing same through a series of devices including series connected transformers to a power unit and modifying the input in respect of a load placed upon said power unit; said circuit further including means for sensing when the load is missing and allowing said power unit to remain in a standby mode of operation until a load is sensed.

Claim 41

Dependent Claim 153 words

An inverter circuit including circuitry components for performing various functions, said circuitry including: means for receiving an AC power input; means for modifying said AC power received to a high frequency AC output supplied to a load; means for storing a DC voltage; means for providing power factor correction for the circuit by feeding back a portion of the high frequency AC output as a DC output voltage to said means for storing said DC voltage via a current limiting inductor and a DC blocking capacitor; means for taking said stored DC voltage and providing same through a series of devices including series connected transformers to a power unit and modifying the input in respect of a load placed upon said power unit; said circuit further including means for sensing when the load is missing and allowing said power unit to remain in a standby mode of operation until a load is sensed.

Claim 42

Dependent Claim 36 words

The circuit of claim 39 wherein said series connected transformers cause a frequency shift in power generated therethrough which synchronizes with any fluctuations in input power, to maintain current levels to a load placed thereon constant.

Claim 43

Dependent Claim 28 words

The circuit of claim 40, wherein one of said series connected transformers is capable of being removed from the circuit when the load is removed from the circuit.

Claim 44

Dependent Claim 10 words

The circuit of claim 41 including a shutdown protection circuit.

Claim 45

Dependent Claim 63 words

The circuit of claim 42 wherein said shutdown protection circuit comprises a control winding on one of the series connected transformers, a sense winding on a load driving transformer, and a transistor which, when turned on shorts out the control winding through a diode bridge removing one of the series transformers from the circuit, reducing power in an inverter circuit being fed thereby.

Claim 46

Dependent Claim 38 words

The circuit of claim 43 further including a Zener diode which control the actuation of the transistor by engaging same when a voltage above its breakdown voltage is generated by the sense winding of the load powering transformer.

Claim 47

Dependent Claim 14 words

The circuit of claim 44 accommodating two sources of AC voltage for powering, thereof.

Claim 48

Dependent Claim 24 words

The circuit of claim 45 wherein input power from a low voltage source passes along a primary path wherein said low voltage is doubled.

Claim 49

Dependent Claim 19 words

The circuit of claim 46 wherein said primary path includes a voltage doubler when outputs a doubled DC voltage.

Claim 50

Dependent Claim 26 words

The circuit of claim 47 wherein input power from a high voltage source is passed directly through a secondary path including a full wave bridge rectifier.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-03-24	1995-09-23	1996-03-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-03-24	1999-09-23	2000-03-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-03-24	2003-09-23	2004-03-24	$7700.00	Window Closed / Lapsed

Inverter with power factor correction circuit

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