System and method for charging batteries

• US 7,808,211 B2
• Filed: 03/31/2009
• Issued: 10/05/2010
• Est. Priority Date: 10/23/2003
• Status: Active Grant

• Current Assignee: Schumacher Electric Corporation
• Original Assignee: Schumacher Electric Corporation
• Inventors: Johnson, Thomas Finis, Pacholok, David R., Chen, Xiao Ping
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): Fantu; Yalkew
• Application Number:
  US12/415,337
• Publication Number:
  US 20090206796A1
• Time in Patent Office: 553 Days
• Field of Search: 320/140, 320/157
• US Class Current: 320/140
• 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

Abstract

A high frequency battery charger includes a converter, drive logic, and control logic. The converter transforms a DC voltage into a high frequency AC voltage. The drive logic controls a conversion of the high frequency AC voltage through a train of pulses. The control logic adjusts the output of the converter to maximize a charging cycle of a battery. The method of transforming an AC input into a direct current output used to charge a rechargeable battery includes transforming an AC input into a first DC output; transforming the first DC output into a high frequency AC output; transforming the high frequency AC output into a second DC output; and passing a charging current to an external load when the load is correctly connected to an output.

Claims

1. A method of charging a rechargeable battery by way of a high frequency battery charger, the method comprising the steps of:

(a) transforming an AC input into a first DC output;

(b) transforming the first DC output into a high frequency AC output;

(c) transforming the high frequency AC output into a second DC output;

(d) sensing the voltage of said second DC output;

(e) sensing the voltage of said rechargeable battery; and

(f) passing a charging current to said rechargeable battery only when said rechargeable battery is correctly connected to said high frequency battery charger and said voltage of said second DC output and said voltage of said rechargeable battery exceed predetermined thresholds, and after passing said charging current to said rechargeable battery, continuing to monitor the voltage of the rechargeable battery and the voltage of said battery charger;

comparing the voltage of the rechargeable battery with the voltage of said battery charger, generating a signal representative of a defective battery condition when a scaled value of said battery charger voltage exceeds a scaled value of the voltage of said rechargeable battery;

automatically modifying predetermined charging cycle in response to said defective battery condition representative signal.

2. The method of claim 1 wherein the step of transforming the first DC input into a high frequency AC output comprises actuating a plurality switches coupled to a primary of a high frequency transformer.

3. The method of claim 1 further comprising the step of monitoring the charging current with a processor.

4. The method of claim 1 further comprising the step of providing a spark resistance when a load is connected in a reverse polarity.

5. The method of claim 1 wherein the act step of passing the charging current comprises passing the charging current onto a battery only when the charging current is below a predetermined threshold.

6. The method of claim 1 wherein the charging current comprises a pulsating current.

7. The method as recited in claim 1, wherein step (f) includes:

automatically terminating said charging cycle in response to said defective battery condition representative signal.