Bidirectional dc-dc converter, power conditioner, and distributed power system

Patent metadata

Field	Value
Publication number	US-2018013291-A1
Application number	US-201615537845-A
Country	US
Kind code	A1
Filing date	Jan 25, 2016
Priority date	Jan 28, 2015
Publication date	Jan 11, 2018
Grant date	—

Abstract

A low-voltage circuit in a bidirectional DC-DC converter converts output AC power from a high-voltage circuit to DC power to charge a smoothing reactor and discharge the smoothing reactor, and includes an active snubber circuit including switching elements and each having a backward diode and a snubber capacitor. The snubber capacitor of the active snubber circuit has its one end connected to a drain end of the switching elements and has its other end connected to a node between a center tap of a high-frequency transformer and a smoothing reactor.

First claim

1 . A bidirectional DC-DC converter, comprising:
a primary converter circuit configured to convert power between direct current power flowing through a first input-output terminal of the bidirectional DC-DC converter and alternating current power flowing through a primary winding of a high-frequency transformer; and a secondary converter circuit configured to convert power between alternating current power flowing through a secondary winding of the high-frequency transformer and direct current power flowing through a second input-output terminal of the bidirectional DC-DC converter and convert alternating current power output from the primary converter circuit to direct current power, the secondary converter circuit including a first group of switching elements each including a backward diode and being connected to a secondary coil of the high-frequency transformer, the primary converter circuit and the secondary converter circuit allowing bidirectional conversion of power between the primary and secondary converter circuits, the secondary converter circuit further including an active snubber circuit including a second group of switching elements each including a backward diode and being connected in parallel and a snubber capacitor connected in series to the second group of switching elements,
the snubber capacitor in the active snubber circuit having a first end connected to the second group of switching elements and a second end opposite to the first end and being connected to a center tap of the high-frequency transformer.

2 . The bidirectional DC-DC converter according to claim 1 , wherein
the secondary converter circuit includes
a smoothing capacitor connected between a positive terminal and a negative terminal at an input-output terminal of the secondary converter circuit, and
a smoothing reactor functioning as an energy storage element and having a first end connected to the positive terminal and to the smoothing capacitor,
the secondary winding of the high-frequency transformer includes a first secondary winding and a second secondary winding, a first end of the first secondary winding and a first end of the second secondary winding are connected to each other to form a center tap, and the center tap is connected to a second end of the smoothing reactor opposite to the first end, the first group of switching elements includes a first switching element and a second switching element, the second group of switching elements includes a third switching element and a fourth switching element, the first switching element has a drain connected to a source of the third switching element and to a second end of the first secondary winding opposite to the center tap, the second switching element has a drain connected to a source of the fourth switching element and a second end of the second secondary winding opposite to the center tap, the first switching element and the second switching element have sources connected to the negative terminal and to the smoothing capacitor, and the first end of the snubber capacitor is connected to drains of the third switching element and the fourth switching element, and the second end of the snubber capacitor opposite to the first end is connected to the center tap of the high-frequency transformer and to the second end of the smoothing reactor.

3 . A power conditioner, comprising:
the bidirectional DC-DC converter according to claim 1 ; a DC-DC converter configured to raise an output voltage from a direct current power source or a solar module, and input the voltage to the bidirectional DC-DC converter; and a bidirectional DC-AC converter configured to convert direct current outputs from the bidirectional DC-DC converter and the DC-DC converter to alternating currents and transfer or receive alternating current power to or from a utility grid or a load.

4 . The power conditioner according to claim 3 , further comprising:
a controller configured to control an on or off operation of the switching elements in the bidirectional DC-DC converter to control an amount of direct current power that is input to or output from the first input-output terminal and the second input-output terminal of the bidirectional DC-DC converter.

5 . A distributed power system, comprising:
the power conditioner according to claim 3 ; a power generator configured to output power to the DC-DC converter; and a storage battery configured to store power and to be charged with power or discharge power through the bidirectional DC-DC converter in accordance with a difference between an amount of power from the power generator and an amount of electric load.

6 . A power conditioner, comprising:
the bidirectional DC-DC converter according to claim 2 ; a DC-DC converter configured to raise an output voltage from a direct current power source or a solar module, and input the voltage to the bidirectional DC-DC converter; and a bidirectional DC-AC converter configured to convert direct current outputs from the bidirectional DC-DC converter and the DC-DC converter to alternating currents and transfer or receive alternating current power to or from a utility grid or a load.

7 . The power conditioner according to claim 6 , further comprising:
a controller configured to control an on or off operation of the switching elements in the bidirectional DC-DC converter to control an amount of direct current power that is input to or output from the first input-output terminal and the second input-output terminal of the bidirectional DC-DC converter.

8 . A distributed power system, comprising:
the power conditioner according to claim 4 ; a power generator configured to output power to the DC-DC converter; and a storage battery configured to store power and to be charged with power or discharge power through the bidirectional DC-DC converter in accordance with a difference between an amount of power from the power generator and an amount of electric load.

9 . A distributed power system, comprising:
the power conditioner according to claim 6 ; a power generator configured to output power to the DC-DC converter; and a storage battery configured to store power and to be charged with power or discharge power through the bidirectional DC-DC converter in accordance with a difference between an amount of power from the power generator and an amount of electric load.

10 . A distributed power system, comprising:
the power conditioner according to claim 7 ; a power generator configured to output power to the DC-DC converter; and a storage battery configured to store power and to be charged with power or discharge power through the bidirectional DC-DC converter in accordance with a difference between an amount of power from the power generator and an amount of electric load.

Assignees

• Omron Tateisi Electronics Co

Inventors

• Ohashi Makoto
• Nishikawa Takeo
• Hyodo Takashi
• Fujihata Isao
• Suetomi Masayuki
• Shimizu Masaaki

Classifications

• H02M3/33584

  Bidirectional converters · CPC title

• H02M3/24

  by static converters · CPC title

• H02J7/35

  with light sensitive cells · CPC title

• H02M7/68

  by static converters · CPC title

• H02J2101/24

  Photovoltaics · CPC title