BATTERY CURRENT MEASUREMENT

• US 20190064274A1
• Filed: 08/25/2017
• Published: 02/28/2019
• Est. Priority Date: 08/25/2017
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Inventors: Fu, Hankey, Lin, Lifan
• Granted Patent: US 10,641,831 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H02J 2207/10 Control circuit supply, e.g. means for supplying power to the control circuit
• CPC Class Codes: H02J 9/062 for AC powered loads

Abstract

A method of detecting a battery current in an uninterruptible power supply and a system directed to the same is provided and includes providing a battery current to a battery along a charging path using a charger, opening the charging path to stop the battery current to the battery, determining a first total current supplied by the charger, while the charging path is opened, enabling the battery current to be provided to the battery, determining a second total current supplied by the charger, while the battery current is being supplied to the battery, and determining a value representative of the battery current.

Claims

1. A method of detecting a battery current in an uninterruptible power supply, the method comprising acts of:

using a charger, providing a battery current to a battery along a charging path;

opening the charging path to stop the battery current to the battery;

determining a first total current supplied by the charger, while the charging path is opened;

enabling the battery current to be provided to the battery;

determining a second total current supplied by the charger, while the battery current is being supplied to the battery; and

determining a value representative of the battery current.

2. The method of claim 1, further including acts of storing a first current value indicative of the first total current supplied by the charger.

3. The method of claim 2, wherein determining the battery current includes subtracting the first current value from the second total current.

4. The method of claim 1, wherein opening the charging path includes opening a switch disposed in the charging path.

5. The method of claim 4, wherein enabling the battery current to be provided to the battery includes closing the switch.

6. An uninterruptible power supply system, the system including:

an input configured to receive input power having an input voltage;

a battery configured to store battery power;

an output configured to provide output power derived from at least one of the input power and the battery power;

a charging circuit, connected to the battery and power circuitry, the charging circuit configured to provide a total current, a first portion of which is provided to the battery and a second portion of which is provided to the power circuitry;

a charger current sensor configured to detect the total current and provide an indication of the total current;

a switch connected to the battery and being configured to selectively control provision of current to the battery; and

a controller, coupled to the switch and to the charger current sensor, the controller being configured to;

open the switch to prevent the battery from receiving the first portion of the total current;

receive, from the charger current sensor, a first sense signal indicative of the total current;

close the switch to enable the battery to receive the first portion of the total current;

receive, from the charger current sensor, a second sense signal indicative of the total current; and

determine a value representative of the first portion of the total current.

7. The system of claim 6, wherein the charging circuit includes the charger current sensor.

8. The system of claim 6, wherein the charger current sensor includes a differential amplifier and a resistor.

9. The system of claim 8, wherein the differential amplifier is configured to detect a current through the resistor.

10. The system of claim 9, wherein the current through the resistor is the total current.

11. The system of claim 6, wherein the controller is further configured to store a first current value representative of the first sense signal.

12. The system of claim 11, wherein the first current value is equivalent to the second portion of the total current.

13. The system of claim 6, wherein the second portion of the total current is substantially independent of the first portion of the total current.

14. The system of claim 6, further including an activation switch.

15. The system of claim 14, wherein the activation switch is a Bipolar Junction Transistor (BJT) having a base connection, a collector connection, and an emitter connection.

16. The system of claim 15, wherein the switch is a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) having a gate connection, a source connection, and a drain connection.

17. The system of claim 16, wherein a gate voltage at the gate connection of the switch is controlled substantially by a collector current drawn by the collector connection of the activation switch.

18. The system of claim 17, wherein the collector current is controlled substantially by a base current provided to the base connection of the activation switch.

19. The system of claim 18, wherein the base current is controlled substantially by the controller.

20. An uninterruptible power supply system, the system comprising:

a charger, connected to a battery and a logic power supply, the charger configured to provide a total current, a first portion of which is provided to the battery and a second portion of which is provided to the logic power supply, the charger including a charger current sensor configured to detect the total current and provide an indication of the total current; and

means for controlling the charger current sensor to detect the first portion of the total current and the second portion of the total current.