US6737762B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Generator with DC boost for uninterruptible power supply system or for enhanced load pickup
Assignee: Onan Corp
•
Filing: 2001-10-26
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Granted: 2004-05-18
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Expires: 2021-10-26
Abstract
Abstract A local power generation system generates a substantially DC voltage at an inverter input, which is modulated to generate a resulting output AC power signal to a load. The inverter input voltage may be obtained from an engine generator, providing an AC power signal that is rectified, or from a fuel cell generator providing a DC voltage that is converted to the desired voltage value at the inverter input. An energy storage device helps maintain the DC voltage when load power draw increases, until the engine (or fuel cell reaction) accelerates enough to accommodate the increased power demand. The system may also be used in an uninterruptible power supply (UPS) application, in which the load draws power from a utility-provided AC power source until a fault condition appears. When the fault condition appears, the load switches its power draw from the utility-provided AC power source to the inverter output. The energy storage device helps maintain the DC voltage at the inverter input until the generator (engine or fuel cell) starts and accelerates to a level sufficient provide the DC voltage. The system may also include switching devices for providing uninterruptible power to a critical load, while permitting a noncritical load to be subjected to a fault-condition on the utility-provided AC power signal for a short period of time, before switching to receive power from the inverter output.
Inventors
- 👤 David J. Koenig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:19
CPC Classifications
H; H02; H02J; H02J9/00; H02J9/04; H02J9/06; H02J9/062; H02J9/068; Y; Y02; Y02B; Y02B90/00; Y02B90/10
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
205 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; a fault condition detector, including an input that is coupled to a utility to detect a fault condition at the utility, and including an output that is coupled to the generator to initiate a generator startup after the fault condition has been detected; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device that provides power to the first load device during the generator startup; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output.
Claim 2
Independent Claim
205 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; a fault condition detector, including an input that is coupled to a utility to detect a fault condition at the utility, and including an output that is coupled to the generator to initiate a generator startup after the fault condition has been detected; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device that provides power to the first load device during the generator startup; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output.
Claim 3
Dependent Claim
22 words
The system of claim 1 , in which the generator includes at least one of a fuel cell and an engine generator.
Claim 4
Dependent Claim
27 words
The system of claim 2 , in which the engine generator is at least one of a variable speed engine generator and a constant speed engine generator.
Claim 5
Dependent Claim
44 words
The system of claim 1 , further including a first rectifier coupled in series between the generator output and the inverter input, the first rectifier having a first rectifier input and a first rectifier output, the first rectifier input coupled to the generator output.
Claim 6
Dependent Claim
57 words
The system of claim 4 , further including a second DC-to-DC converter coupled in series between the first rectifier and the first inverter, the second DC-to-DC converter having a second converter input and a second converter output, the second converter input coupled to the first rectifier output, and the second converter output coupled to the inverter input.
Claim 7
Dependent Claim
24 words
The system of claim 4 , further including an AC-to-AC voltage converter coupled in series between the generator output and the first rectifier input.
Claim 8
Dependent Claim
56 words
The system of claim 1 , further including a second DC-to-DC converter coupled in series between the generator output and the inverter input, the second DC-to-DC converter including a second converter input and a second converter output, the second converter input coupled to the generator output and the second converter output coupled to the inverter input.
Claim 9
Dependent Claim
23 words
The system of claim 1 , in which the energy storage device includes at least one of a capacitor and a rechargeable battery.
Claim 10
Dependent Claim
14 words
The system of claim 8 , in which the capacitor includes an electrochemical capacitor.
Claim 11
Dependent Claim
46 words
The system of claim 1 , in which the first DC-to-DC converter includes a step-up DC-to-DC converter converting a lower voltage received at the first converter input from the energy storage device to a higher voltage provided by the first converter output to the inverter input.
Claim 12
Dependent Claim
42 words
The system of claim 1 , in which the energy supply circuit includes a rectifier that includes: a first diode, having an anode coupled to the generator output; and a second diode, having an anode coupled to the utility-provided AC power source.
Claim 13
Dependent Claim
47 words
The system of claim 1 , in which the energy supply circuit includes a second DC-to-DC converter, having a second converter input and a second converter output, the second converter input coupled to the generator output, and the second converter output coupled to the energy storage device.
Claim 14
Dependent Claim
96 words
The system of claim 1 , in which the energy supply circuit includes: a rectifier, having a rectifier input coupled to at least one of the generator output and the utility-provided AC power source, the rectifier having a rectifier output; a switch, coupling the rectifier output to the energy storage device, the switch including a control terminal; and a regulator circuit, coupled to the energy storage device to sense a voltage, and coupled to the control circuit of the switch to regulate conduction of the switch to maintain a predetermined voltage at the energy storage device.
Claim 15
Dependent Claim
53 words
The system of claim 1 , in which the energy storage device includes an energy storage capacity that is limited to an approximate energy needed to approximately maintain a steady voltage at the inverter input when a motor within the first load device is started and draws surge power from the inverter output.
Claim 16
Dependent Claim
66 words
The system of claim 1 , in which the energy storage device includes an energy storage capacity that is limited to an approximate energy needed to approximately maintain a steady voltage at the inverter input during a first time period in which the engine generator is started and until the generator output reaches a steady-state output voltage sufficient to maintain the voltage at the inverter input.
Claim 17
Dependent Claim
23 words
The system of claim 15 , in which the first time period also includes a waiting period before the engine generator is started.
Claim 18
Dependent Claim
20 words
The system of claim 16 , in which the waiting period is between about 0.5 second and about 5 seconds.
Claim 19
Dependent Claim
15 words
The system of claim 17 , in which the waiting period is about 3 seconds.
Claim 20
Dependent Claim
49 words
The system of claim 1 , in which the energy storage device includes an energy storage capacity that is limited to an approximate energy needed to approximately maintain a steady voltage at the inverter input for an interim time that is between about 0.5 seconds and about 60 seconds.
Claim 21
Dependent Claim
15 words
The system of claim 19 , in which the interim time is about 10 seconds.
Claim 22
Dependent Claim
95 words
The system of claim 1 , further including: a first switch, coupled between the utility-provided AC power source and the inverter output, the first switch including a first switch-control input; and the fault condition detector circuit is coupled to the utility-provided AC power source to detect a fault condition of the utility-provided AC power source, the detector circuit including a detector output coupled to the first switch-control input to operate the first switch to isolate the inverter output and the first load device from the utility-provided AC power source when the fault condition is detected.
Claim 23
Dependent Claim
24 words
The system of claim 21 , in which the fault condition includes an at least ½ cycle undervoltage of the utility-provided AC power source.
Claim 24
Dependent Claim
29 words
The system of claim 21 , in which the inverter circuit includes a synchronization circuit to synchronize a signal at the inverter output to the utility-provided AC power source.
Claim 25
Dependent Claim
42 words
The system of claim 23 , in which the synchronization circuit operates to synchronize the signal at the inverter output to the utility-provided AC power source at least after the first switch isolates the first load from the utility-provided AC power source.
Claim 26
Dependent Claim
53 words
The system of claim 21 , in which the fault detector output provides a control signal to the first switch-control input to operate the first switch to recouple the first load to the utility-provided AC power source after the fault detector detects the ceasing of the fault condition at the AC power source.
Claim 27
Dependent Claim
36 words
The system of claim 25 , in which the inverter momentarily operates synchronously in parallel with the recoupled utility-provided AC power source to avoid a momentary break in power to the first load during the recoupling.
Claim 28
Dependent Claim
67 words
The system of claim 21 , in which the fault detector output provides a control signal to the first switch-control input to operate the first switch to recouple the first load to the utility-provided AC power source after the fault detector detects the ceasing of the fault condition at the AC power source, and after the energy storage device has been recharged for a predetermined delay period.
Claim 29
Dependent Claim
42 words
The system of claim 25 , in which the inverter circuit includes a synchronization circuit to synchronize a signal at the inverter output to the utility provided AC power source before the first load is recoupled to the utility-provided AC power source.
Claim 30
Dependent Claim
64 words
The system of claim 1 , further providing power to a second load device, and further including a switch, having first and second states, the switch conductively coupling the second load to the utility-provided AC power source when the switch is in the first state, the switch conductively coupling the second load to the inverter output when the switch is in the second state.
Claim 31
Dependent Claim
51 words
The system of claim 29 , in which the generator is coupled to the switch to provide a control signal transitioning the switch from the first state to the second state after the generator has been turned on and is capable of maintaining the inverter input at a predetermined sufficient voltage.
Claim 32
Dependent Claim
55 words
The system of claim 29 , further including a timer coupled to the generator and the switch, the timer including a timer output coupled to the switch to provide a control signal to transition the switch from the first state to the second state at a predetermined time after the generator has been turned on.
Claim 33
Dependent Claim
33 words
The system of claim 29 , further including: a second switch, coupling the inverter output to the first load; and a third switch, coupling the second load in parallel with the first load.
Claim 34
Independent Claim
152 words
A method of providing an electrical AC output signal to a first load, the method including: generating a first approximately DC voltage from a fuel; modulating the first DC voltage into the AC output signal; providing the AC output signal to the first load; and transferring energy from an energy storage device onto the first DC voltage to maintain the first DC voltage at a first predetermined DC voltage value while the first load draws a surge power AC output signal, and in which the transferring includes converting a second DC voltage value provided by the energy storage device to the first predetermined DC voltage value, and in which the transferring includes using the energy storage device having an energy storage capacity that is limited to approximately the energy storage needed to maintain the first DC voltage long enough for a generator to accelerate, to accommodate the surge power AC output signal.
Claim 35
Independent Claim
152 words
A method of providing an electrical AC output signal to a first load, the method including: generating a first approximately DC voltage from a fuel; modulating the first DC voltage into the AC output signal; providing the AC output signal to the first load; and transferring energy from an energy storage device onto the first DC voltage to maintain the first DC voltage at a first predetermined DC voltage value while the first load draws a surge power AC output signal, and in which the transferring includes converting a second DC voltage value provided by the energy storage device to the first predetermined DC voltage value, and in which the transferring includes using the energy storage device having an energy storage capacity that is limited to approximately the energy storage needed to maintain the first DC voltage long enough for a generator to accelerate, to accommodate the surge power AC output signal.
Claim 36
Dependent Claim
30 words
The method of claim 33 , further including transferring energy to the energy storage device from at least one of: an generator-provided power source; and a utility-provided AC power source.
Claim 37
Independent Claim
168 words
A method of providing AC electrical power to a first load, the method including: decoupling the first load from a utility-provided AC power source that, during normal operation, is provided to the first load without AC-to-DC-to AC conversion, upon detecting a fault condition at the utility-provided AC power source; modulating a DC voltage to provide backup AC power; coupling the backup AC power to the first load when the first load is decoupled from the utility-provided AC power source; turning on an generator to provide energy to the DC voltage; and transferring energy from an energy storage device to the DC voltage during a time from the turning on of the generator to a time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value, and in which the transferring energy from the energy storage device includes DC-to-DC converting a second voltage value provided by the energy storage device to the first predetermined voltage value of the DC voltage.
Claim 38
Independent Claim
168 words
A method of providing AC electrical power to a first load, the method including: decoupling the first load from a utility-provided AC power source that, during normal operation, is provided to the first load without AC-to-DC-to AC conversion, upon detecting a fault condition at the utility-provided AC power source; modulating a DC voltage to provide backup AC power; coupling the backup AC power to the first load when the first load is decoupled from the utility-provided AC power source; turning on an generator to provide energy to the DC voltage; and transferring energy from an energy storage device to the DC voltage during a time from the turning on of the generator to a time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value, and in which the transferring energy from the energy storage device includes DC-to-DC converting a second voltage value provided by the energy storage device to the first predetermined voltage value of the DC voltage.
Claim 39
Dependent Claim
27 words
The method of claim 35 , in which the decoupling the first load includes triggering the decoupling by detecting a zero-cross of the utility-provided AC power source.
Claim 40
Dependent Claim
27 words
The method of claim 35 , in which the detecting the fault condition includes detecting an at least ½ cycle undervoltage of the utility-provided AC power source.
Claim 41
Dependent Claim
74 words
The method of claim 35 , in which the transferring energy from the energy storage device includes using the energy storage device having an energy storage capacity that is limited to approximately the energy storage needed to maintain the first DC voltage for a time from the turning on of the generator to the time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value.
Claim 42
Dependent Claim
32 words
The method of claim 35 , further including transferring energy to the energy storage device from at least one of: the generated power from the generator; and the utility-provided AC power source.
Claim 43
Dependent Claim
50 words
The method of claim 35 , further including transferring a second load from the utility provided-AC power source to the backup AC power from the modulated DC voltage after a time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value.
Claim 44
Dependent Claim
49 words
The method of claim 35 , in which the modulating the DC voltage to provide backup AC power to the first load includes synchronizing the backup AC power to the utility-provided AC power source at least upon the decoupling of the first load from the utility-provided AC power source.
Claim 45
Dependent Claim
32 words
The method of claim 35 , further including: detecting a ceasing of the fault condition at the utility-provided AC power source; and recoupling the first load to the utility-provided AC power source.
Claim 46
Dependent Claim
27 words
The method of claim 42 , in which the recoupling follows the detecting the ceasing of the fault condition and a recharging of the energy storage device.
Claim 47
Dependent Claim
31 words
The method of claim 42 , further including synchronizing the backup AC power to the utility-provided AC power source before the recoupling the first load to the utility-provided AC power source.
Claim 48
Dependent Claim
17 words
The method of claim 42 , further including decoupling the first load from the backup AC power.
Claim 49
Dependent Claim
37 words
The method of claim 44 , in which the decoupling follows an operating the backup AC power synchronously in parallel with the utility-provided AC power source momentarily to avoid a break in power to the first load.
Claim 50
Independent Claim
235 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output; a first rectifier coupled in series between the generator output and the inverter input, the first rectifier having a first rectifier input and a first rectifier output, the first rectifier input coupled to the generator output; and a second DC-to-DC converter coupled in series between the first rectifier and the first inverter, the second DC-to-DC converter having a second converter input and a second converter output, the second converter input coupled to the first rectifier output, and the second converter output coupled to the inverter input.
Claim 51
Independent Claim
235 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output; a first rectifier coupled in series between the generator output and the inverter input, the first rectifier having a first rectifier input and a first rectifier output, the first rectifier input coupled to the generator output; and a second DC-to-DC converter coupled in series between the first rectifier and the first inverter, the second DC-to-DC converter having a second converter input and a second converter output, the second converter input coupled to the first rectifier output, and the second converter output coupled to the inverter input.
Claim 52
Dependent Claim
24 words
The system of claim 47 , further including an AC-to-AC voltage converter coupled in series between the generator output and the first rectifier input.
Claim 53
Independent Claim
185 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output, wherein the energy supply circuit includes a rectifier that includes: a first diode, having an anode coupled to the generator output; and a second diode, having an anode coupled to the utility-provided AC power source.
Claim 54
Independent Claim
185 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output, wherein the energy supply circuit includes a rectifier that includes: a first diode, having an anode coupled to the generator output; and a second diode, having an anode coupled to the utility-provided AC power source.
Claim 55
Independent Claim
239 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output, wherein the energy supply circuit includes: a rectifier, having a rectifier input coupled to at least one of the generator output and the utility-provided AC power source, the rectifier having a rectifier output; a switch, coupling the rectifier output to the energy storage device, the switch including a control terminal; and a regulator circuit, coupled to the energy storage device to sense a voltage, and coupled to the control circuit of the switch to regulate conduction of the switch to maintain a predetermined voltage at the energy storage device.
Claim 56
Independent Claim
239 words
A system providing AC electrical power to a first load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output, wherein the energy supply circuit includes: a rectifier, having a rectifier input coupled to at least one of the generator output and the utility-provided AC power source, the rectifier having a rectifier output; a switch, coupling the rectifier output to the energy storage device, the switch including a control terminal; and a regulator circuit, coupled to the energy storage device to sense a voltage, and coupled to the control circuit of the switch to regulate conduction of the switch to maintain a predetermined voltage at the energy storage device.
Claim 57
Independent Claim
250 words
A system providing AC electrical power to a first load device and a second load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output; a switch, having first and second states, the switch conductively coupling the second load to the utility-provided AC power source when the switch is in the first state, the switch conductively coupling the second load to the inverter output when the switch is in the second state; and a timer coupled to the generator and the switch, the timer including a timer output coupled to the switch to provide a control signal to transition the switch from the first state to the second state at a predetermined time after the generator has been turned on.
Claim 58
Independent Claim
250 words
A system providing AC electrical power to a first load device and a second load device, the system including: a generator, including a generator output; an inverter circuit, including an inverter input and an inverter output, the inverter input coupled to the generator output, the inverter output adapted to be coupled to the first load device; an energy storage device; a first DC-to-DC converter circuit, including a first converter input and a first converter output, the first converter input coupled to the energy storage device, and the first converter output coupled to the inverter input; and an electrical energy supply circuit, including an energy supply circuit input and an energy supply circuit output, the energy supply circuit output coupled to the energy storage device, the energy supply circuit input coupled to a power source that is selected from at least one of a utility-provided AC power source outside of the system and the generator output; a switch, having first and second states, the switch conductively coupling the second load to the utility-provided AC power source when the switch is in the first state, the switch conductively coupling the second load to the inverter output when the switch is in the second state; and a timer coupled to the generator and the switch, the timer including a timer output coupled to the switch to provide a control signal to transition the switch from the first state to the second state at a predetermined time after the generator has been turned on.
Claim 59
Independent Claim
221 words
A method of providing AC electrical power to a first load, the method including: decoupling the first load from a utility-provided AC power upon detecting a fault condition at the utility-provided AC power source; modulating a DC voltage to provide backup AC power; coupling the backup AC power to the first load when the first load is decoupled from the utility-provided AC power source; turning on an generator to provide energy to the DC voltage; and transferring energy from an energy storage device to the DC voltage during a time from the turning on of the generator to a time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value, and in which the transferring energy from the energy storage device includes DC-to-DC converting a second voltage value provided by the energy storage device to the first predetermined voltage value of the DC voltage, and wherein the transferring energy from the energy storage device includes using the energy storage device having an energy storage capacity that is limited to approximately the energy storage needed to maintain the first DC voltage for a time from the turning on of the generator to the time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value.
Claim 60
Independent Claim
221 words
A method of providing AC electrical power to a first load, the method including: decoupling the first load from a utility-provided AC power upon detecting a fault condition at the utility-provided AC power source; modulating a DC voltage to provide backup AC power; coupling the backup AC power to the first load when the first load is decoupled from the utility-provided AC power source; turning on an generator to provide energy to the DC voltage; and transferring energy from an energy storage device to the DC voltage during a time from the turning on of the generator to a time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value, and in which the transferring energy from the energy storage device includes DC-to-DC converting a second voltage value provided by the energy storage device to the first predetermined voltage value of the DC voltage, and wherein the transferring energy from the energy storage device includes using the energy storage device having an energy storage capacity that is limited to approximately the energy storage needed to maintain the first DC voltage for a time from the turning on of the generator to the time at which the generator is supplying sufficient power to maintain the DC voltage at a first predetermined voltage value.
References Cited (Backward Citations)
US4405867A
Cited
US4401895A
Cited
US4465943A
Cited
US4703191A
Cited
US4827152A
Cited
US5198970A
Cited
US5053635A
Cited
US5332927A
Cited
US5670833A
Cited
US5619076A
Cited
US5579197A
Cited
US5635773A
Cited
US5646458A
Cited
US5767591A
Cited
US5811960A
Cited
US5880537A
Cited
US5994794A
Cited
US6487096B1
Cited
US6288456B1
Cited
US6122181A
Cited
US6198176B1
Cited
US6134124A
Cited
US6172432B1
Cited
US6184593B1
Cited
US6266260B1
Cited
US6194880B1
Cited
US6367259B1
Cited
US6243277B1
Cited
US20020047309A1
Cited
US6369461B1
Cited
US6281595B1
Cited
US6385056B1
Cited
US6344985B1
Cited
US6304006B1
Cited
US20020126517A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-05-18 | 2007-11-17 | 2008-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-05-18 | 2011-11-17 | 2012-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-05-18 | 2015-11-17 | 2016-05-18 | $7700.00 | Window Closed / Lapsed |