Device for a battery charger

• US 20050225300A1
• Filed: 02/21/2003
• Published: 10/13/2005
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: CTEK Sweden AB (CTEK Holding AB)
• Original Assignee: Creator Teknisk Utveckling AB
• Inventors: Nordlof, Peter
• Granted Patent: US 7,629,774 B2
• Time in Patent Office: Days
• US Class Current: 320/141
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A device for reducing the output current of a primary switched battery charger, which charger includes an input DC power circuit, a high frequency transformer and control unit for modulating the DC input power. The device includes elements for measuring pulse ratio of switch pulses on the output side of the charger, elements for measuring peak value of output voltage, elements for differentially amplifying the signals measured and elements for integrating voltage/current of the differentially amplified signals, wherein the integrated voltage/current is used for modulating the input DC power in order to reduce the output current. The device includes elements for measuring the output effect of the charger, elements for measuring the output voltage of the charger, elements for dividing the signals measured and elements for multiplexing voltage/current of the output from the elements for dividing, wherein the multiplexed voltage/current is used for modulating the input DC power in order to reduce the output current.

Claims

1. Device for reducing the output current of a primary switched battery charger, which charger comprises an input DC power circuit, a high frequency transformer and a control unit for modulating the DC input power, characterised in that it comprises means for measuring pulse ratio of switch pulses on the output side of the charger;

means for measuring peak value of output voltage;

means for differentially amplifying the signals measured; and

means for integrating voltage/current of the differentially amplified signals, wherein the integrated voltage/current is used for modulating the input DC power in order to reduce the output current.

2. Device according to claim 1, characterised in a switch capable of switching on and off the connection between the means for differentially amplifying and the means for integrating.

3. Device for reducing the output current of a primary switched battery charger, which charger comprises an input DC power circuit, a high frequency transformer and a control unit for modulating the DC input power, characterised in that it comprises:

means for measuring the output effect of the charger;

means for measuring the output voltage of the charger;

means for dividing the signals measured; and

means for multiplexing voltage/current of the output from the means for dividing, wherein the multiplexed voltage/current is used for modulating the input DC power in order to reduce the output current.

4. Device according to claim 3, wherein the means for measuring the output effect of the charger is arranged to measure the pulse ratio of switch pulses on the output side of the charger.

5. Device according to claim 3, wherein the means for measuring the output voltage of the charger is arranged to measure the peak value of the output voltage.

6. Device according to claim 3, wherein the means for measuring the output voltage of the charger is arranged to measure the effective value of the output voltage.

7. Device according to claim 5, wherein the means for dividing the signals measured is arranged to:

compare the signals measured;

obtain a resulting signal by subtracting the pulse ratio from the effective value or the peak value; and

invert the resulting signal.

8. Device according to claim 3, wherein the means for multiplexing the voltage/current is arranged to:

integrate the output voltage and the output from the means for dividing the signals.

9. Device according to claim 3, further comprising a switch capable of switching on and off the connection between the means for dividing and the means for multiplexing.

10. Method for reducing the output current of a primary switched battery charger, which charger comprises an input DC power circuit, a high frequency transformer and control unit for modulating the DC input power, characterised in the steps of:

measuring the output effect of the charger;

measuring the output voltage of the charger;

dividing the signals measured; and

multiplexing voltage/current of the output from the means for dividing, wherein the multiplexed voltage/current is used for modulating the input DC power in order to reduce the output current.

11. Method according to claim 10, wherein the step of measuring the output effect comprises the step of:

measuring the pulse ratio of switch pulses on the output side of the charger.

12. Method according to claim 10, wherein the step of measuring the output voltage comprises the step of:

measuring the peak value of the output voltage.

13. Method according to claim 10, wherein the step of measuring the output voltage comprises the step of:

measuring the effective value of the output voltage.

14. Method according to claim 12, wherein the step of dividing the signals comprises the steps of:

comparing the signals measured;

obtaining a resulting signal by subtracting the pulse ratio from the effective value or the peak value; and

inverting the resulting signal.

15. Method according to claim 10, wherein the step of multiplexing the signals comprises the step of:

integrating the signals.

16. Method according to claim 10, further comprising the step of:

switching on and off a low-current area of the charging.

18. Computer readable medium comprising instructions for bringing a programmable device to perform the method according to claim 10.

17. Method for reducing the output current of a primary switched battery charger, which charger comprises an input DC power circuit, a high frequency transformer and a control unit for modulating the DC input power, characterised in the steps of:

measuring pulse ratio of switch pulses on the output side of the charger;

measuring peak value of output voltage;

differentially amplifying the signals measured;

integrating voltage/current of the differentially amplified signals, wherein the integrated voltage/current is used for modulating the input DC power in order to reduce the output current.