Resonant power converter with primary-side tuning and zero-current switching
First Claim
1. A resonant power converter with AC full-wave primary-side resonance and zero-current switching adapted to convert power from an input DC voltage source to a DC terminal output load comprising:
- an input stage configured to receive a first power signal from a DC input source;
an AC full-wave magnetic interface configured to receive a second power signal from said input stage;
an output stage configured to impose an output signal across a load by receiving said second power signal from said magnetic interface; and
wherein said input stage includes a zero-current switch topology comprising a resonant capacitor, a resonant inductor and a unidirectional conducting device with a switching element arranged in series within said zero-current switch.
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Abstract
A DC power converter consisting of a series-resonant branch used to transform a DC voltage source into a DC current source exhibiting, a uni-polar, zero-current-switching characteristic. Frequency of the series-resonant branch, acting in concert with reflected load parameters, provides a forced oscillation frequency, Fo, component to an AC voltage source generated across the input winding of a power transformer by the resonant capacitor. Complex load parameters allow AC input current, displaced by 90° from the AC voltage source, to flow in the transformer primary winding throughout a composite, carrier-frequency cycle. Another component of the carrier-frequency consists of a resonant, natural oscillation frequency, Fn, resulting from resonance by the AC voltage source capacitance with the open-circuit inductance of the primary winding on the input power transformer. The composite carrier-frequency, Fo+Fn, transported through the input power transformer is directed to a rectifier/filter assembly and applied as a DC voltage to an output load. Thus, the uni-polar DC series-resonant branch is converted into an AC power transfer function, fully isolated from the input power switch, by the AC voltage source capacitor. The power transfer function characterizing a bi-polar power inverter requires a single power switch referenced to the input power return bus.
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Citations
15 Claims
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1. A resonant power converter with AC full-wave primary-side resonance and zero-current switching adapted to convert power from an input DC voltage source to a DC terminal output load comprising:
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an input stage configured to receive a first power signal from a DC input source;
an AC full-wave magnetic interface configured to receive a second power signal from said input stage;
an output stage configured to impose an output signal across a load by receiving said second power signal from said magnetic interface; and
wherein said input stage includes a zero-current switch topology comprising a resonant capacitor, a resonant inductor and a unidirectional conducting device with a switching element arranged in series within said zero-current switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
an input winding and a non-polarized output winding wherein said input winding is connected to said input stage and said output winding is connected to said output stage.
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3. The resonant power converter of claim 2 wherein said magnetic interface input winding is connected in parallel with said resonant capacitor.
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4. The resonant power converter of claim 2 wherein said output stage further comprises:
a rectifying element, a filter inductor connected to said rectifying element, a filter capacitor connected to said filter inductor and a fly-back rectifying element connected to said filter inductor.
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5. The resonant power converter of claim 4 wherein said output stage filtering elements may be implemented in any combination of half or full-wave rectifier/filter configuration.
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6. The resonant power converter of claim 1 further comprising:
a control mechanism connected to said zero-current switch configured to selectively vary said switching element between an open and a closed position.
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7. The resonant power converter of claim 6 wherein said control mechanism comprises a pulse-position-modulation (PPM) control mode as a negative feedback loop.
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8. The resonant power converter of claim 6 wherein said PPM control mode further comprises:
a sensor configured to open said switching element upon cessation of current in said zero-current switch.
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9. The resonant power converter of claim 3 further comprising:
a power transfer function wherein said resonant capacitor offers a full-wave AC voltage source to said input winding of said magnetic interface in isolation from said switching element situated within said zero-current switch.
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10. The resonant power converter of claim 7 wherein said PPM control mode initiates a forced frequency, Fo, component upon said resonant capacitor and said magnetic interface input winding during the positive region of the full-wave sinusoidal transition.
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11. The resonant power converter of claim 7 wherein said PPM control mode initiates a resonant frequency, Fn, component upon said resonant capacitor and said magnetic interface input winding during the negative region of the full-wave sinusoidal transition.
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12. The resonant power converter of claim 7 wherein said PPM control mode combines said forced frequency, Fo, with said resonant frequency, Fn, to synthesize a composite full-wave sinusoidal carrier-frequency comprised of said frequency component Fo, and said frequency component, Fn.
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13. The resonant power converter of claim 11 wherein peak voltage amplitude of said resonant component, Fn, appears additive with said input DC voltage source to impose the hold-off voltage sustained by said unidirectional conducting device in combination with said switching element within said zero-current switch.
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14. The resonant power converter of claim 12 wherein a design coefficient, K, introduces a maximum duty cycle [1/(1+K)] allowed by said PPM control on said zero-current switch.
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15. The resonant power converter of claim 7 wherein said PPM negative feedback control loop monitors said output signal across said load and upon sensing an out-of-limit deviation alters time between pulses to said switching element to restore said output signal within prescribed limits.
Specification