DC-DC converter

• US 7,333,348 B2
• Filed: 06/06/2006
• Issued: 02/19/2008
• Est. Priority Date: 03/18/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Mitsui & Company Limited, Winz Corporation
• Inventors: Tan, Nozomi, Nakamura, Yoshimichi, Horiuchi, Shoji
• Primary Examiner(s): Patel; Rajnikant B.
• Application Number:
  US11/447,387
• Publication Number:
  US 20060227577A1
• Time in Patent Office: 623 Days
• Field of Search: 363 16- 20, 363/97, 363/21.02, 363/71, 363/132, 363/65, 363/67, 363/95, 363/37
• US Class Current: 363/16
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: H02M 7/05 Capacitor coupled rectifiers
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects

Abstract

There is provided a high-efficiency DC-DC converter which comprises a voltage resonance circuit to which electric power from a low-voltage direct-current power supply, including a household fuel cell and a solar cell, is input and performs DC-AC conversion by zero-voltage switching, an insulating high-frequency transformer which transmits the converted power, a current resonance circuit which is provided on the secondary side of the transformer and performs zero-current switching, a rectifier circuit which rectifies the output from the current resonance circuit, and a smoothing circuit which rectifies the output from the rectifier circuit.

Claims

1. A DC-DC converter comprising:

a first voltage resonance circuit including first switching elements which are so connected as to be alternately switched, to which direct-current power is input from a low-voltage direct-current power supply the first voltage resonance circuit converting the direct-current power to an alternative-current power and outputting the alternative-current power;

a first driver circuit which alternately and selectively turns on and turns off the first switching elements at a zero crossing timing to maintain the first voltage resonance circuit in a resonance mode, wherein substantially no conductive current is supplied to the first switching element and substantially no voltage is applied to the first switching element at the zero cross timing;

a first insulating high-frequency transformer which has a primary side and a secondary side, the output voltage being applied to the primary side from the first voltage resonance circuit;

a first current resonance circuit which is connected to the secondary side of the first transformer;

a first rectifier circuit which rectifies the output current output from the first current resonance circuit;

a first smoothing circuit which smoothes the output voltage from the first rectifier circuit to output a first output voltage;

a second voltage resonance circuit including second switching elements which are so connected as to be alternately switched, to which the direct-current power is input from the low-voltage direct-current power supply, the second voltage resonance circuit converting the direct-current power to an alternative-current power and outputting the alternative-current power

a second driver circuit which alternately and selectively turns on and turns off the second switching elements at the zero cross timing to maintain the second voltage resonance circuit in a resonance mode, wherein substantially no conductive current is supplied to the first switching element and substantially no voltage is applied to the first switching elements at the zero cross timing;

a second insulating high-frequency transformer which has a primary side and a secondary side, the output voltage being applied to the primary side from the secondary voltage resonance circuit;

a second current resonance circuit which is connected to the secondary side of the second transformer;

a second rectifier circuit which rectifies the output current output from the second current resonance circuit;

a second smoothing circuit which smoothes the output voltage from the second rectifier circuit to output a second output voltage;

a pulse-width modulation circuit which pulse-width modulates the first and second output voltages from the first and second smoothing circuits, and comprises a first diode connected between the high potential sides of the first and second output voltages, a second diode connected to the low potential sides of the first and second output voltages, and a third switching element connected between the first and second diodes;

a third smoothing circuit which smoothes the output voltage from the pulse-width modulation circuit to output a third output voltage; and

a pulse generator which generates a pulse signal to alternately turn on and turn off the third switching element, the turning on of the third switching element connecting the first and second diodes to the third smoothing circuit in series, and the turning off of the third switching element connecting the first and second diodes to the third smoothing circuit in parallel.

2. The DC-DC converter according to claim 1, wherein the first and second switching elements of the first and second voltage resonance circuits are connected in one of the bridge type and the push-pull type.

6. The DC-DC converter according to claim 1, wherein the pulse generator includes a photo-coupler which electrically disconnects between the third smoothing circuit and the third switching elements.

7. The DC-DC converter according to claim 1, wherein the low-voltage direct-current power supply corresponds to a fuel cell, a solar cell, or a wind-up generator.

3. A DC-DC converter comprising:

a voltage resonance circuit including first switching elements which are so connected as to be alternatively switched, to which direct-current power is input from a low-voltage direct-current power supply, the voltage resonance circuit converting the direct-current power to an alternative-current power and outputting the alternative-current power

an insulating high-frequency transformer which has a primary side and a secondary side, the output voltage being applied to the primary side from the first voltage resonance circuit;

first and second current resonance circuits which are connected to the secondary side of the first transformer;

first and second rectifier circuits which rectify the output currents output from the first and second current resonance circuits;

first and second smoothing circuits which smooth the output voltages from the first and second rectifier circuits to output first and second output voltages;

a pulse-width modulation circuit which pulse-width-modulates the first and second output voltages from the first and second smoothing circuits, and comprises a first diode connected between the high potential sides of the first and second output voltages, a second diode connected to the low potential sides of the first and second output voltages, and a second switching element connected between the first and second diodes;

a third smoothing circuit which smoothes the output voltage from the pulse-width modulation circuit to output a third output voltage; and

a pulse generator which generates a pulse signal to alternately turn on and turn off the third switching element, the turning on of the third switching element connecting the first and second diodes to the third smoothing circuit in series, and the turning off of the third switching element connecting the first and second diodes to the third smoothing circuit in parallel.

4. The DC-DC converter according to claim 3, wherein the first switching elements of the first voltage resonance circuit are connected in one of the bridge type and the push-pull type.

8. The DC-DC converter according to claim 3, wherein the pulse generator includes a photo-coupler which electrically disconnects between the third smoothing circuit and the second switching elements.

9. The DC-DC converter according to claim 3, wherein the low-voltage direct-current power supply corresponds to a fuel cell, a solar cell, or a wind-up generator.

5. A DC-DC converter comprising:

a voltage resonance circuit including first switching elements which are so connected as to be alternately switched, to which direct-current power is input from a low-voltage direct-current power supply, the voltage resonance circuit converting the direct-current power to an alternative-current power and outputting the alternative-current power;

a first driver circuit which alternately and selectively turns on and turns off the first switching elements at a zero cross timing to maintain the first voltage resonance circuit in a resonance mode, wherein substantially no conductive current is supplied to the first switching element and substantially no voltage is applied to the first switching element at the zero cross timing;

a first and second insulating high-frequency transformer each of which has a primary side and a secondary side, the output voltage being applied to the primary side from the first voltage resonance circuit;

first and second current resonance circuits which are connected to the secondary sides of the first and secondary transformers respectively;

first and second rectifier circuits which rectify the output currents output from the first and second current resonance circuits;

first and second smoothing circuits which smooth the output voltages from the first and second rectifier circuits to output first and second output voltages;

a pulse-width modulation circuit which pulse-width modulates the first and second output voltages from the first and second smoothing circuits, and comprises a first diode connected between the high potential sides of the first and second output voltages, a second diode connected to the low potential sides of the first and second output voltages, and a second switching element connected between the first and second diodes;

a third smoothing circuit which smoothes the output from the pulse-width modulation circuit to output a third output voltage; and

a pulse generator which generates a pulse signal to alternately turn on and turn off the third switching element, the turning on of the third switching element connecting the first and second diodes to the third smoothing circuit in series, and the turning off of the third switching element connecting the first and second diodes to the third smoothing circuit in parallel.

10. The DC-DC converter according to claim 5, wherein the pulse generator includes a photo-coupler which electrically disconnects between the third smoothing circuit and the second switching elements.

11. The DC-DC converter according to claim 5, wherein the low-voltage direct-current power supply corresponds to a fuel cell, a solar cell, or a wind-up generator.