Method and a device for charging a battery

• US 6,677,731 B2
• Filed: 11/20/2002
• Issued: 01/13/2004
• Est. Priority Date: 02/28/2000
• Status: Expired due to Fees

• Current Assignee: Bombardier Transportation GmbH (Bombardier Incorporated)
• Original Assignee: Bombardier Transportation GmbH (Bombardier Incorporated)
• Inventors: Ljunggren, Benny
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US10/204,708
• Publication Number:
  US 20030141852A1
• Time in Patent Office: 419 Days
• Field of Search: 320/127, 320/128, 320/137, 320/152, 320/157, 320/159, 320/160, 320/162, 320/164
• US Class Current: 320/152
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A device for charging a battery comprises an alternating current source, a rectifier being connected with its input to the alternating current source and being connected with its output to the battery for charging thereof. It also has a member for measuring the charging current from the rectifier to the battery and a means (13) for comparing the measured charging current with a current limit value and an arrangement adapted to control the voltage on the output of the rectifier based on information about said comparison and decrease it if the measured current exceeds the current limit value for reduction of the charging current. A unit (23, 28, 30) is adapted to form the current limit value by comparing a current value formed by the value of said measured charging current with a restriction on its positive rise speed with a predetermined maximum current limit value, and to determine the lowest of the so obtained current value and said maximum current limit value as said current limit value for the comparison of said means (13).

Claims

1. A method for charging a battery via a rectifier being connected with its input to an alternating current source adapted to provide at least one consumer other than the battery with electric energy and being connected with its output to the battery, the method comprising:

measuring charging current from the rectifier to the battery;

comparing the measured charging current with a current limit value; and

controlling the output voltage from the rectifier to reduce the charging current to the battery if the measured charging current exceeds the current limit value,

wherein the current limit value is determined by comparing a predetermined maximum current limit value with a theoretical current value derived from the measured charging current with a restriction on its positive rise speed, and selecting the lowest of the predetermined maximum current limit value and the theoretical current value as the current limit value for the comparison with the measured charging current.

2. The method according to claim 1, wherein deriving the theoretical current value further comprises:

comparing a previous theoretical charging current value with the measured charging current;

selecting the lowest of the previous theoretical charging current value and the measured charging current as an intermediate value;

adding a maximum current value addition per unit of time to the intermediate value to derive the theoretical charging current value.

3. The method according to claim 1, wherein electric energy is fed to the alternating current source via a contact line for railway vehicles.

4. The method according to claim 1, wherein a direct voltage is converted into an alternating voltage in an inverter for feeding to the input of the rectifier.

5. The method according to claim 4, wherein the output voltage on the output of the rectifier is controlled by controlling the inverter.

6. The method according to claim 1, wherein the output voltage on the output of the rectifier is controlled by controlling the rectifier.

7. A device for charging a battery comprising:

an alternating current source;

a rectifier connected with its input to the alternating current source and being connected with its output to the battery for charging thereof, the alternating current source being adapted to feed at least one consumer other than the battery with electric energy;

a member for measuring the charging current from the rectifier to the battery;

a means for comparing the measured charging current with a current limit value; and

an arrangement adapted to control the voltage on the output of the rectifier based on information about said comparison and decrease it if the measured current exceeds the current limit value for reduction of the charging current, the arrangement comprising a unit adapted to generate the current limit value by comparing a predetermined maximum current limit value with a theoretical current value derived by applying a restriction on positive rise speed to the measured charging current, to determine the lowest of the predetermined maximum current limit value and the theoretical current value.

an arrangement adapted to control the voltage on the output of the rectifier based on information about said comparison and decrease it if the measured current exceeds the current limit value for reduction of the charging current, the arrangement comprising a unit adapted to generate the current limit value by comparing a predetermined maximum current limit value with a theoretical current value derived from the measured charging current with a restriction on its positive rise speed to determine the lowest of the predetermined maximum current limit value and the theoretical current value.

8. The device according to claim 7, wherein the unit comprises:

means for comparing a previous theoretical charging current value with the measured charging current and selecting the lowest of them as an intermediate value; and

means for adding a maximum current value addition per unit of time to the intermediate value to derive the theoretical charging current value.

9. The device according to claim 7,wherein the device is adapted to be a part of the electric system of a railway vehicle, and the alternating current source is adapted to obtain electric energy from a contact line for the railway vehicle.

10. The device according to claim 9, wherein the battery is adapted to be used for supplying electric energy to an engine of the vehicle when starting the vehicle.

11. The device according to claim 9, wherein the consumer comprises equipment included in the vehicle selected from the group consisting of fans, main compressors, and lighting equipment.

12. The device according to claim 9, wherein the consumer is connected in parallel with the battery.

13. The device according to claim 7, further comprising an inverter adapted to convert a direct voltage into an alternating voltage for feeding the input of the rectifier.

14. The device according to claim 13, wherein a transformer for changing the level of the voltage from the inverter to the consumer and the battery is arranged between the inverter and the battery and the consumer.

15. The device according to claim 13, wherein the arrangement is adapted to control the inverter for controlling the output voltage on the output of the rectifier.

16. The device according to claim 7, wherein the arrangement is adapted to control the rectifier for controlling the output voltage on the output of the rectifier.

17. A method for regulating charging current to a battery, the method comprising:

measuring charging current supplied to the battery;

comparing the measured charging current with a current limit value; and

reducing the charging current to the battery if the measured charging current exceeds the current limit value,

wherein the current limit value is set higher than the measured charging current by a predetermined amount, except that the current limit value is subject to a maximum rise speed when the measured charging current rises faster than the maximum rise speed, and the current limit value is subject to a predetermined maximum current limit.

18. The method according to claim 17, wherein subjecting the current limit value to the maximum rise speed comprises:

receiving a first measurement of the measured charging current;

incrementing the first measurement by a predetermined amount;

receiving a second measurement of the measured charging current; and

selecting the lowest of the incremented first measurement and the second measurement as the current limit value.

19. The method according to claim 17, wherein the a rectifier supplies the charging current to the battery, the rectifier being connected with its input to an alternating current source adapted to provide at least one consumer other than the battery with electric energy and being connected with its output to the battery.

20. The method according to claim 18, wherein the a rectifier supplies the charging current to the battery, the rectifier being connected with its input to an alternating current source adapted to provide at least one consumer other than the battery with electric energy and being connected with its output to the battery.