Three-level soft-switched converters
First Claim
1. A soft-switched, constant-frequency, three-level power converter with phase-shift modulation comprising:
- an input power source;
four controllable switching devices connected in series adapted to connect to said input power source, each of said controllable switching devices comprising a switch, an antiparallel diode coupled across said switch and a capacitor coupled across said switch;
a transformer having a primary and secondary winding;
an inductor arranged on the primary side of said transformer so that when an outer switch and a corresponding inner switch of said four controllable switching devices connected in series are periodically open and closed in phase the volt-second product of a winding of said inductor is maximal and the volt-second product of said windings of said transformer is minimal, and when a said outer switch and a said corresponding inner switch of said four controllable switching devices connected in series are periodically open and closed in antiphase the volt-second product of said winding of said inductor is minimal and the volt-second product of said windings of said transformer is maximal;
a plurality of capacitors arranged on said primary side of said transformer providing power sources with voltages that are fractions of the voltage of said input power source and coupled to said four controllable switches so that the voltage across a nonconducting said controllable switch is a fraction of said voltage of said input source;
an output circuit for coupling a load to said secondary winding of said transformer.
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Accused Products
Abstract
Three-level, constant-frequency, soft-switched isolated converters provide zero-voltage-switching (ZVS) conditions for the turn-on of all primary switches over a wide range of input voltage and output load. These converters achieve ZVS with the minimum duty cycle loss and circulating current, which optimizes the conversion efficiency. The ZVS of the primary switches is achieved by the energy stored in an inductor on the primary side of the isolation transformer. The inductor and transformer are arranged so that a change in the phase shift between the outer and inner pair of switches of the series connection of four switches changes the volt-second product on the windings of the transformer and the windings of the inductor in opposite directions. In some embodiments the primary-side inductor is coupled inductor with two windings, whereas in the other embodiments the inductor has only one winding.
84 Citations
12 Claims
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1. A soft-switched, constant-frequency, three-level power converter with phase-shift modulation comprising:
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an input power source;
four controllable switching devices connected in series adapted to connect to said input power source, each of said controllable switching devices comprising a switch, an antiparallel diode coupled across said switch and a capacitor coupled across said switch;
a transformer having a primary and secondary winding;
an inductor arranged on the primary side of said transformer so that when an outer switch and a corresponding inner switch of said four controllable switching devices connected in series are periodically open and closed in phase the volt-second product of a winding of said inductor is maximal and the volt-second product of said windings of said transformer is minimal, and when a said outer switch and a said corresponding inner switch of said four controllable switching devices connected in series are periodically open and closed in antiphase the volt-second product of said winding of said inductor is minimal and the volt-second product of said windings of said transformer is maximal;
a plurality of capacitors arranged on said primary side of said transformer providing power sources with voltages that are fractions of the voltage of said input power source and coupled to said four controllable switches so that the voltage across a nonconducting said controllable switch is a fraction of said voltage of said input source;
an output circuit for coupling a load to said secondary winding of said transformer. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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2. A soft-switched, constant-frequency, three-level power converter with phase-shift modulation comprising:
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an input power source;
four controllable switching devices connected in series adapted to connect to said input power source, each of said controllable switching devices comprising a switch, an antiparallel diode coupled across said switch and a capacitor coupled across said switch;
a transformer having a primary and secondary winding;
an inductor arranged on the primary side of said transformer so that when an outer switch and a corresponding inner switch of said four controllable switching devices connected in series are periodically open and closed in phase the volt-second product of a winding of said transformer is maximal and the volt-second product of a winding of said inductor is minimal, and when a said outer switch and a said corresponding inner switch of said four controllable switching devices connected in series are periodically open and closed in antiphase the volt-second product of said winding of said transformer is minimal and the volt-second product of said winding of said inductor is maximal;
a plurality of capacitors arranged on said primary side of said transformer providing power sources with voltages that are fractions of the voltage of said input power source and coupled to said four controllable switches so that the voltage across a nonconducting said controllable switch is a fraction of said voltage of said input source;
an output circuit for coupling a load to said secondary winding of said transformer.
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Specification