Digital residual current detecting system

1. A system for charging an Electric Vehicle (EV) comprising:

a first drive winding wound on a first core, wherein the first drive winding is driven with a first input signal;

a second drive winding wound on a second core, wherein the second drive winding is driven with a second input signal, and wherein the second input signal has an opposite polarity of the first input signal;

a first comparator configured to receive a first drive signal from the first drive winding, and output a signal based on the saturation of the first core;

a second comparator configured to receive a second drive signal from the second drive winding, and output a signal based on the saturation of the second core; and

a processor configured to receive the output signals from the first comparator and the second comparator, determine a saturation status of the first core and the second core, and determine a potential leakage signal based said saturation status of the first core and the second core, and stop charging the EV if a leakage current based on the determined potential leakage signal exceeds a set threshold.

2. The system of claim 1 , wherein the first input signal is a high frequency voltage, and wherein the second input signal is a high frequency voltage.

3. The system of claim 1 , wherein the first input signal is a high frequency current, and wherein the second input signal is a high frequency current.

4. The system of claim 1 , wherein the first comparator is configured to receive a reference signal and compare the reference signal to the first drive signal and output the signal based on the comparison indicating the saturation of the first core, and wherein the second comparator is configured to receive the reference signal and compare the reference signal to the second drive signal and output the signal based on the comparison indicating the saturation of the second core.

5. The system of claim 1 , wherein the processor is further configured to:

flip a polarity of the first input signal and the second input signal to a first polarity if both the first core and the second core are determined to be saturated based on the determined saturation status of the first core and the second core.

6. The system of claim 5 , wherein the processor is further configured to:

record a first rising edge time and a first period for the first signal input and for the second signal input.

7. The system of claim 6 , wherein the processor is further configured to:

flip the polarity of the first input signal and the second input to a second polarity.

8. The system of claim 7 , wherein the processor is further configured to:

record a second rising edge time and a second period for the first signal input and the second signal input.

9. The system of claim 8 , wherein the processor is further configured to:

calculate an initial value based on the differences in first rising edge times and second rising edge times between the first signal input and the second signal input, and the sum of the first and second periods of the first signal input and the second signal input, wherein the determined potential leakage signal is based on the calculated initial value.

10. The system of claim 9 , wherein the processor is further configured to:

scale the calculated initial value; and

filter the scaled initial value, wherein the determined potential leakage signal is based on the filtered initial value.

11. The system of claim 1 , further comprising:

a single turn winding on both the first core and the second core; and

a test circuit coupled to the single turn winding.

12. The system of claim 1 , further comprising:

an H-bridge circuit electrically coupled to the first winding and the second winding.

13. The system of claim 1 , wherein the first comparator and the second comparator have a voltage threshold of 0.3V.

14. The system of claim 9 , wherein the calculated initial value is proportional to the leakage current.

15. A method for charging an Electric Vehicle (EV) comprising:

driving a first drive winding wound on a first core with a first input signal;

driving a second drive winding wound on a second core with a second input signal, wherein the second input signal has an opposite polarity of the first input signal;

receiving a first drive signal from the first drive winding at a first comparator;

outputting a signal based on the saturation of the first core from the first comparator;

receiving a second drive signal from the second drive winding at a second comparator;

outputting a signal based on the saturation of the second core from the second comparator;

receiving, at a processor, output signals from the first comparator and the second comparator;

determining, at the processor, a saturation status of the first core and the second core;

determining, at the processor, a potential leakage signal based said saturation status of the first core and the second core; and

stopping, at the processor, charging the EV if a leakage current based on the determined potential leakage signal exceeds a set threshold.

16. The method of claim 15 , wherein determining the potential leakage signal based said saturation status of the first core and the second core further comprises:

flipping, by the processor, a polarity of the first input signal and the second input signal to a first polarity if both the first core and the second core are determined to be saturated based on the determined saturation status of the first core and the second core.

17. The method of claim 16 , wherein determining the potential leakage signal based said saturation status of the first core and the second core further comprises:

recording a first rising edge time and a first period for the first signal input and for the second signal input.

18. The method of claim 17 , wherein determining the potential leakage signal based said saturation status of the first core and the second core further comprises:

flipping the polarity of the first input signal and the second input to a second polarity.

19. The method of claim 18 , wherein determining the potential leakage signal based said saturation status of the first core and the second core further comprises:

recording a second rising edge time and a second period for the first signal input and the second signal input.

20. The method of claim 19 , wherein determining the potential leakage signal based said saturation status of the first core and the second core further comprises:

calculating an initial value based on the differences in first rising edge times and second rising edge times between the first signal input and the second signal input, and the sum of the first and second periods of the first signal input and the second signal input, wherein the determined potential leakage signal is based on the calculated initial value.