REMOTE BATTERY CHARGING SYSTEM WITH DYNAMIC VOLTAGE ADJUSTMENT AND METHOD OF USE

• US 20090289604A1
• Filed: 05/26/2008
• Published: 11/26/2009
• Est. Priority Date: 05/26/2008
• Status: Active Grant

• Current Assignee: Galvion Power Systems Incorporated
• Original Assignee: Steve Carkner
• Inventors: CARKNER, STEVE
• Granted Patent: US 8,138,723 B2
• Time in Patent Office: Days
• US Class Current: 320/151
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

In a remote battery charging system comprising a charging circuit there is always a voltage loss due to inherent resistances in the system from such things as connectors and conductors. These resistances create voltages losses in the system such that charging times are increased substantially. The present invention compensates for voltage losses on the system by generating a dynamic adjustment voltage over the charging period. A voltage translator circuit is used to measure charging circuit output voltage and current over a plurality of incremental time periods during the charging period an calculate a signal proportional to changes in output voltage and current over the incremental time period. The signal is then applied to the charging circuit to offset any voltage losses.

Claims

1. A remote battery charging system comprising a charging circuit for generating an adjustable output voltage V_o and an output current I_o for charging an at least one battery having a predetermined maximum battery voltage V_Batt, wherein said at least one battery is connected to said charging circuit by a first conductor and a second conductor having an aggregate inherent resistance R_i causing an aggregate voltage loss V_l, the charging circuit comprising means for compensating said V_l comprising means for dynamic V_o adjustment over a charging time.

2. The remote battery charging system of claim 1 wherein said charging time includes a first time period wherein output current I_o is constant (CC mode) and a second time period wherein V_o at the battery terminals is constant (CV mode) so that V_o is always greater than V_Batt when the charging circuit is charging and V_o approaches V_Batt as charging current approaches zero for a fully charged battery.

3. The remote battery charging system of claim 1 wherein said means for dynamic V_o adjustment comprises a voltage translator circuit.

4. The remote battery charging system of claim 3 wherein said voltage translator circuit comprises means for measuring at time intervals of “

t”

said I_o and V_o, means for generating a signal S proportional to changes in I_o and V_o during one of said time intervals of “

t”

, means for applying said signal S to generate an variable offset voltage V_off and means for summing said V_off and V_o thereby compensating for V_l.

5. The remote battery charging system of claim 4 wherein said means for measuring I_o and V_o, said means for generating signal S, said means for applying signal S to generate V_off over time interval “

t” and

means for summing V_off and V_o comprise a microprocessor.

6. The remote battery charging system of claim 5 wherein said microprocessor is adapted to sum V_off and V_o during the CC mode while ensuring that V_o is always less than V_Batt.

7. The remote battery charging system of claim 6 wherein the microprocessor is further adapted to sum V_off to V_o during the CV mode while ensuring that V_o is greater than V_Batt.

8. The remote battery charging system of claim 7 wherein the at least one battery includes a temperature sensitive resistor for battery temperature measurement.

9. The remote battery charging system of claim 8 wherein said temperature sensitive resistor is in communication with the microprocessor by a third conductor.

10. The remote battery charging system of claim 9 wherein said third conductor is deemed to experience a V_l equal to V_l in said first and said second conductors respectively.

11. The remote battery charging system of claim 10 wherein the microprocessor is adapted to compute the aggregate V_l in the first and second conductors by doubling said third conductor V_l and then calculate and apply V_off to V_o based on the doubled third conductor V_l.

12. A remote battery charging system comprising a charging circuit having an adjustable output voltage V_o and a limited output current I_o for charging during a time period T an at least one battery having a predetermined maximum battery voltage V_Batt, wherein said at least one battery is connected to said charging circuit by a first positive conductor and a second ground conductor having an aggregate inherent resistance R_i causing an aggregate voltage loss V_l, the charging circuit comprising an adjustable voltage source for generating said V_o, a voltage monitor for monitoring V_o during T, a current limiter for limiting said I_o , a current monitor for monitoring I_o during T, and a micro-processor for dynamic V_o adjustment by a V_off during T in order to compensate for V_l and optimize I_o.

13. The remote battery charging system of claim 12 wherein said micro-processor is a mathematical summing node in series with said current monitor and wherein said current monitor transmits the magnitude of I_o to said mathematical summing node where it is converted into a control signal S′

for transmission to said adjustable voltage source to adjust V_o by said V_off to optimize I_o.

14. The remote battery charging system of claim 12 wherein said at least one battery comprises a safety thermistor for battery temperature sensing.

15. The remote battery charging system of claim 14 wherein the charging circuit further comprises an analogue to digital converter and wherein said safety thermistor is connected to said analogue to digital converter by a third wire having similar resistance as the first positive and second ground conductors.

16. The remote battery charging system of claim 15 wherein the analogue to digital converter is connected in series to the micro-processor for controlling a bias current in the third conductor for battery temperature measurement, so that when the micro-processor terminates said bias current in said third conductor the third conductor is capable of measuring V_off in the positive first and second ground conductors.

17. A method of using a remote battery charging system having a charging circuit for generating an adjustable output voltage V_o and an output current I_o for charging an at least one battery during a time T, said at least one battery having a predetermined maximum battery voltage V_Batt, said method comprising the steps of:

a. Connecting said at least one battery to said charging circuit by a first positive conductor and a second ground conductor having an aggregate inherent resistance R_i causing an aggregate voltage loss V_l;

b. Measuring during T and at intervals of “

t”

said I_o using a current monitor and said V_o using a voltage monitor;

c. Generating a signal S proportional to changes in I_o and V_o during one of said time intervals of “

t”

;

d. Applying said signal S to generate a variable offset voltage V_off; and

,

e. Summing said V_off and V_o thereby compensating for V_l.

18. The method of claim 17 further including the steps of:

a. providing a mathematical summing node in series with said current monitor;

b. measuring the magnitude of I_o;

c. transmitting the magnitude of I_o to said mathematical summing node;

d. using the mathematical summing mode to convert the magnitude of I_o into a control signal S′

; and

,

e. transmitting said control signal S′

to said adjustable voltage source to adjust V_o by said V_off to optimize I_o.

19. The method of claim 18 including the steps of:

a. providing a micro-processor within said charging circuit for measuring during T and at time intervals of “

t”

, I_o and V_o, generating signal S, applying signal 5 to generate an variable offset voltage V_off, and summing V_off and V_o; and

,

b. using said micro-processor to sum V_off and V_o during a constant current charging mode while ensuring that the sum is always less than the maximum allowable voltage of V_Batt.

20. The method of claim 19 further including the steps of:

a. adding a temperature sensitive resistor to said at least one battery for battery temperature measurement;

b. connecting said temperature sensitive resistor between said second ground conductor and a third conductor wherein said third conductor has a resistance similar to the first positive and second ground conductors;

c. providing an analogue to digital converter within the battery charger;

d. connecting said analogue to digital converter between the third conductor and the micro-processor;

e. applying a bias current to the third conductor for measuring resistance within the temperature sensitive resistor;

f. terminating said bias current;

g. measuring VI in the third conductor;

h. applying said V_l to the first positive and second ground conductors; and

,

i. calculating V_off based upon the V_l in the first positive and the second ground conductors; and

,

j. adjusting V_o by V_off.