Power Supply Device and Construction Machine

• US 20100096921A1
• Filed: 10/21/2009
• Published: 04/22/2010
• Est. Priority Date: 10/22/2008
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Ishida, Toshihiko, Kimura, Toshihiro, Doi, Tetsuhiro
• Granted Patent: US 8,125,105 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 50/53 in combination with an external power supply, e.g. from overhead contact lines
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A power supply device comprises a bidirectional voltage converter unit that performs voltage stepping up or voltage stepping down between a first terminal and a second terminal; a first switching unit that applies a DC voltage obtained from the first electric power supply source to the first terminal; a second switching unit that applies a DC voltage obtained from the second electric power supply source to the first terminal; a third switching unit that applies a DC voltage obtained from the first electric power supply source to the second terminal; an output unit that outputs a predetermined DC voltage from the second terminal; and a switching control unit that controls switching of the first switching unit, the second switching unit and the third switching unit.

Claims

1. A power supply device that receives supply of electric power from a first electric power supply source or from a second electric power supply source and generates a predetermined DC voltage, comprising:

a bidirectional voltage converter unit that includes a first terminal and a second terminal and performs step-up converting or step-down converting between the first terminal and the second terminal;

a first switching unit that applies a DC voltage obtained from the first electric power supply source to the first terminal of the bidirectional voltage converter unit;

a second switching unit that applies a DC voltage obtained from the second electric power supply source to the first terminal of the bidirectional voltage converter unit;

a third switching unit that applies a DC voltage obtained from the first electric power supply source to the second terminal of the bidirectional voltage converter unit;

an output unit that outputs the predetermined DC voltage from the second terminal of the bidirectional voltage converter unit; and

a switching control unit that controls switching of the first switching unit, the second switching unit and the third switching unit.

2. A power supply device according to claim 1, wherein:

the DC voltage from the first electric power supply source is obtained by rectifying an AC voltage of an AC power supply grid or obtained from an external battery;

the DC voltage from the second electric power supply source is obtained from an internal battery;

the bidirectional voltage converter unit is a bidirectional type of voltage converting chopper circuit; and

the switching control unit controls the switching of the first switching unit, the second switching unit and the third switching unit, on the basis of the DC voltage obtained from the first electric power supply source and the DC voltage obtained from the second electric power supply source.

3. A power supply device according to claim 1, wherein

the switching control unit transmits electric power from the first electric power supply source to the second electric power supply source via the bidirectional voltage converter unit, by opening the first switching unit, closing the second switching unit and closing the third switching unit.

4. A power supply device according to claim 1, wherein

the switching control unit outputs the predetermined DC voltage from the first electric power supply source to the outside via the bidirectional voltage converter unit, by closing the first switching unit, opening the second switching unit and opening the third switching unit.

5. A construction machine that uses an electric motor as a drive power source, comprising:

a power supply device according to claim 1;

an inverter circuit that operates upon the DC output voltage of the power supply device; and

an electric motor driven by the inverter circuit.

6. A construction machine according to claim 5, wherein:

the first electric power supply source is an external AC power supply grid or an external DC power supply; and

the second electric power supply source is a battery internal to a main body of the construction machine.