Load driver with power storage unit

• US 20030146726A1
• Filed: 01/27/2003
• Published: 08/07/2003
• Est. Priority Date: 02/05/2002
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ishikawa, Tetsuhiro, Sugiura, Hiroshi
• Granted Patent: US 6,930,460 B2
• Time in Patent Office: Days
• US Class Current: 318/442
• CPC Class Codes: B60L 15/10 for automatic control superimposed on human control to limit the acceleration of the vehicle, e.g. to prevent excessive motor current electric devices for safety purposes B60L3/00
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2270/20 Inrush current reduction, i.e. avoiding high currents when connecting the battery
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: H02H 9/001 limiting speed of change of electric quantities, e.g. soft switching on or off progressive control of electronic switches for eliminating interferences H03K17/16
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

In a load driving arrangement, electric power is supplied from an auxiliary battery to a main power supply when the power stored by charging in the main power supply is scarce at the startup of the system. The power is supplied to the main power supply by closing relays to connect the auxiliary battery to the neutral point of an auxiliary motor, operating a switching transistor of a bottom arm of an auxiliary-related inverter based on a command from a control circuit, stepping up the voltage from the auxiliary battery by using a coil of the auxiliary motor as a reactor, and supplying the step-up voltage to the main power supply thereby charging the main power supply. At this time, a drive-related inverter and a DC/DC converter are stopped. When the main power supply is charged to a sufficient degree, the relays are opened to drive each load. Accordingly, the load driving arrangement achieves the function of charging the main power supply at low cost when the power stored therein is scarce at the system startup.

Claims

1. A load driver comprising:

an AC motor;

a first power supply outputting a first voltage which is a DC voltage;

a second power supply outputting a second voltage which is a DC voltage;

an inverter receiving said first voltage, converting said first voltage into an AC voltage, outputting said AC voltage to said AC motor, and driving said AC motor;

a converter stepping down said first voltage, outputting the step-down voltage to said second power supply and charging said second power supply; and

a control circuit, wherein when said first voltage is lower than a predetermined voltage,

said second voltage is supplied to a coil of said AC motor, and

said control circuit controls said inverter to step up said second voltage by said coil of said AC motor and said inverter, output the step-up voltage to said first power supply and charge said first power supply, and stops said converter.

2. The load driver according to claim 1, wherein

said AC motor includes a plurality of coils each having one end and the other end, and said second voltage is supplied to a neutral point constituted of respective one-ends, connected together, of all of said plurality of coils.

3. The load driver according to claim 1, wherein

said AC motor includes a plurality of coils each having one end and the other end, respective one-ends of all of said plurality of coils being connected together to constitute a neutral point, and said second voltage is supplied to the other end of one of said plurality of coils.

4. The load driver according to claim 1, further comprising another inverter receiving said first voltage, converting said first voltage into another AC voltage, and outputting said another AC voltage to and driving a vehicle-drive motor for moving a vehicle, wherein

said AC motor is a motor for auxiliary components, and

when said first voltage is lower than said predetermined voltage, said control circuit further stops said another inverter.

5. The load driver according to claim 1, wherein

said AC motor includes:

a first AC motor; and

a second AC motor,

said inverter includes;

a first inverter receiving said first voltage, converting said first voltage into a first AC voltage, outputting said first AC voltage to said first AC motor, and driving said first AC motor; and

a second inverter receiving said first voltage, converting said first voltage into a second AC voltage, outputting said second AC voltage to said second AC motor, and driving said second AC motor and, when said first voltage is lower than said predetermined voltage,

the positive electrode of said second power supply is connected to a first neutral point constituted by connecting together respective one-ends of all coils of said first AC motor, and the negative electrode of said second power supply is connected to a second neutral point constituted by connecting together respective one-ends of all coils of said second AC motor, and

said control circuit controls said first inverter to step up said second voltage by a coil of said first AC motor and said first inverter, output the step-up voltage to said first power supply, and charge said first power supply.

6. The load driver according to claim 1, wherein

said first power supply is one of a power capacitor and a secondary battery.

7. The load driver according to claim 1, wherein

when said first power supply needs to be charged at system startup,

said control circuit controls said inverter to step up said second voltage by said coil of said AC motor and said inverter, output the step-up voltage to said first power supply and charge said first power supply, and stops said converter.

8. A method of controlling charging of a power storage unit in a load driver, said load driver driving a load by a first voltage supplied from a first DC power supply, and said first DC power supply being charged by a second voltage supplied from a second DC power supply which is charged by stepping down said first voltage, comprising:

a first step of making a change in power supply route, when said first DC power supply needs to be charged, from a power supply route to step down said first voltage and charge said second DC power supply, to another power supply route to step up said second voltage and charge said first DC power supply;

a second step of receiving and stepping up said second voltage; and

a third step of outputting the step-up second voltage to said first DC power supply to charge said first DC power supply.

9. The method according to claim 8, wherein

said second voltage is supplied to a coil of an AC motor driven by said first voltage, and

in said second step, said second voltage is stepped up by controlling switching of at least one switching transistor of an inverter driving said AC motor, by said coil of said AC motor and said inverter.

10. A computer-readable recording medium with a program recorded thereon for a computer to execute control of charging of a power storage unit in a load driver, said load driver driving a load by a first voltage supplied from a first DC power supply, and said first DC power supply being charged by a second voltage supplied from a second DC power supply which is charged by stepping down said first voltage, said computer executing:

a first step of making a change in power supply route, when said first DC power supply needs to be charged, from a power supply route to step down said first voltage and charge said second DC power supply, to another power supply route to step up said second voltage and charge said first DC power supply;

a second step of receiving and stepping up said second voltage; and

a third step of outputting the step-up second voltage to said first DC power supply to charge said first DC power supply.

11. The computer-readable recording medium according to claim 10, wherein

said second voltage is supplied to a coil of an AC motor driven by said first voltage, and

in said second step, said second voltage is stepped up by controlling switching of at least one switching transistor of an inverter driving said AC motor, by said coil of said AC motor and said inverter.