Electric vehicle supply equipment and a method of determining a state of a contactor in electric vehicle supply equipment

Patent metadata

Field	Value
Publication number	US-10150374-B2
Application number	US-201615337762-A
Country	US
Kind code	B2
Filing date	Oct 28, 2016
Priority date	Oct 28, 2016
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

Electric vehicle supply equipment includes a contactor having a first set of contacts and a second set of contacts, an amplifier circuit electrically connected to the load side output of the first set of contacts via a first connection and to the load side output of the second set of contacts via a second connection, the amplifier circuit being structured to amplify a voltage difference between a first voltage at the first connection and a second voltage at the second connection, and control electronics structured to compare the amplified voltage difference to a threshold voltage and to determine whether the first and second sets of contacts are closed based on the comparison between the amplified voltage difference and the threshold voltage.

First claim

What is claimed is:

1. Electric vehicle supply equipment comprising:
a contactor having a first set of contacts and a second set of contacts, wherein the first and second sets of contacts each have a line side output structured to electrically couple to an electrical supply and a load side output structured to electrically couple to an electric vehicle;
an amplifier circuit electrically connected to the load side output of the first set of contacts via a first connection and to the load side output of the second set of contacts via a second connection, the amplifier circuit being structured to amplify a voltage difference between a first voltage at the first connection and a second voltage at the second connection; and
control electronics structured to compare the amplified voltage difference to a threshold voltage and to determine whether the first and second sets of contacts are closed based on the comparison between the amplified voltage difference and the threshold voltage,
wherein the line side outputs of the first and second sets of contacts are physically isolated from the load side outputs of the first and second sets of contacts when the first and second sets of contacts are open.

2. The electric vehicle supply equipment of claim 1 , wherein the control electronics are structured to determine that the first and second sets of contacts are closed when the amplified voltage difference is greater than or equal to the threshold voltage.

3. The electric vehicle supply equipment of claim 2 , wherein the control electronics are structured to determine that at least one of the first and second sets of contacts are open when the amplified voltage difference is less than the threshold voltage.

4. The electric vehicle supply equipment of claim 1 , wherein the amplifier is a differential amplifier.

5. The electric vehicle supply equipment of claim 4 , wherein the differential amplifier includes:
an operational amplifier having an inverting input, a non-inverting input, and an output;
a first resistor electrically connected between the output of the operational amplifier and the control electronics;
a second resistor electrically connected between the first connection and the inverting input of the operational amplifier;
a third resistor electrically connected between the second connection and the non-inverting input of the operational amplifier;
a fourth resistor electrically connected between the inverting input of the operational amplifier and the output of the operational amplifier; and
a fifth resistor electrically connected between the non-inverting input of the operational amplifier and ground.

6. The electric vehicle supply equipment of claim 5 , wherein the first, fourth, and fifth resistors have a resistance of about 100 kΩ and the second and third resistors have a resistance of about 4 MΩ.

7. The electric vehicle supply equipment of claim 5 , wherein a resistance of the second resistor is about equal to a resistance of the third resistor and a resistance of the fourth resistor is about equal to a resistance of the fifth resistor.

8. The electric vehicle supply equipment of claim 5 , wherein the operational amplifier is power by a positive supply voltage of about 12 V and a negative supply voltage of about −12 V.

9. The electric vehicle supply equipment of claim 4 , wherein the differential amplifier has a gain of about 0.025.

10. The electric vehicle supply equipment of claim 1 , wherein the control electronics includes a processor and a memory including a routine which, when executed by the processor, causes the processor to compare the amplified voltage difference to a threshold voltage and to determine whether the first and second sets of contacts are closed based on the comparison between the amplified voltage difference and the threshold voltage.

11. The electric vehicle supply equipment of claim 1 , wherein the electric vehicle supply equipment is J1772-compliant.

12. The electric vehicle supply equipment of claim 1 , wherein the electric vehicle supply equipment is structured to electrically connect an electric supply to the electric vehicle; and wherein opening the first and second sets of contacts breaks the electrical connection between the electrical supply and the electric vehicle.

13. Electric vehicle supply equipment comprising:
a contactor having a first set of contacts and a second set of contacts, wherein the first and second sets of contacts each have a line side output structured to electrically couple to an electrical supply and a load side output structured to electrically couple to an electric vehicle;
an amplifier circuit electrically connected to the load side output of the first set of contacts via a first connection and to the load side output of the second set of contacts via a second connection, the amplifier circuit being structured to amplify a voltage difference between a first voltage at the first connection and a second voltage at the second connection; and
control electronics structured to compare the amplified voltage difference to a threshold voltage and to determine whether the first and second sets of contacts are closed based on the comparison between the amplified voltage difference and the threshold voltage, wherein the control electronics are electrically connected to an operating mechanism structured to open and close the first and second sets of contacts; and wherein the control electronics are structured to output a control signal to control the operating mechanism to open or close the first and second sets of contacts.

14. The electric vehicle supply equipment of claim 13 , wherein the control electronics are structured to compare the amplified voltage difference to a threshold voltage and to determine whether the first and second sets of contacts are closed based on the comparison between the amplified voltage difference and the threshold voltage in response to outputting the control signal to the operating mechanism.

15. The electric vehicle supply equipment of claim 13 , wherein the operating mechanism is structured to open the first and second sets of contacts together and to close the first and second sets of contacts together.

16. A method of determining a state of a contactor in electric vehicle supply equipment, the contactor having a first set of contacts and a second set of contacts, wherein the first and second sets of contacts each have a line side output structured to electrically couple to an electrical supply and a load side output structured to electrically couple to an electric vehicle, wherein the method comprises:
providing an amplifier circuit electrically connected to the load side output of the first set of contacts via a first connection and to the load side output of the second set of contacts via a second connection, the amplifier circuit being structured to amplify a voltage difference between a first voltage at the first connection and a second voltage at the second connection;
comparing the amplified voltage difference to a threshold voltage; and
determining whether the first and second sets of contacts are closed based on the comparison between the amplified voltage difference and the threshold voltage,
wherein the line side outputs of the first and second sets of contacts are physically isolated from the load side outputs of the first and second sets of contacts when the first and second sets of contacts are open.

17. The method of claim 16 , further comprising:
determining that the first and second sets of contacts are closed when the amplified voltage difference is greater than or equa

Assignees

• Eaton Corp
• Eaton Intelligent Power Ltd

Inventors

• Xiong Tom
• Hao Jackie
• Yang Andrew
• Lacey Darron Kirby

Classifications

• B60L53/62

  in response to charging parameters, e.g. current, voltage or electrical charge · CPC title

• B60L3/00

  Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption (methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00) · CPC title

• B60L53/16

  Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles · CPC title

• Y02T90/14

  Plug-in electric vehicles · CPC title

• Y02T10/7072

  Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors · CPC title