Isolated high precision pilot voltage generating circuit and electric vehicle supply equipment including the same

• US 10,017,064 B1
• Filed: 12/20/2016
• Issued: 07/10/2018
• Est. Priority Date: 12/20/2016
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Inventors: Yang, Andrew, Xiong, Tom, Zhong, Kevin, Zhuang, Alex, Chen, Martin
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US15/384,553
• Publication Number:
  US 20180170199A1
• Time in Patent Office: 567 Days
• Field of Search: 320109
• CPC Class Codes: B60L 53/16 Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/60 Monitoring or controlling charging stations
• CPC Class Codes: B60L 53/62 in response to charging parameters, e.g. current, voltage or electrical charge
• CPC Class Codes: B60L 53/66 Data transfer between charging stations and vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

An electrical circuit for electric vehicle supply equipment including a pilot control signal unit structured to generate a pilot control signal having a state including one of a high state and a low state, a pilot control signal isolation unit structured to generate an isolated pilot control signal that is isolated from the power lines of the electric vehicle supply equipment and is based on the state of the pilot control signal, and an amplification unit structured to generate a pilot signal based on the state of the pilot control signal. The amplification unit is structured to receive the isolated pilot control signal and the isolated voltage and to use the isolated pilot control signal and the isolated voltage to generate the pilot signal, and the pilot signal is isolated from the power lines of the electric vehicle supply equipment.

Claims

1. An electrical circuit for electric vehicle supply equipment, the electrical circuit comprising:

a power supply unit structured to generate an isolated voltage that is isolated from power lines of the electric vehicle supply equipment;

a pilot control signal unit structured to generate a pilot control signal having a state including one of a high state and a low state;

a pilot control signal isolation unit structured to generate an isolated pilot control signal that is isolated from the power lines of the electric vehicle supply equipment and is based on the state of the pilot control signal; and

an amplification unit structured to generate a pilot signal based on the state of the pilot control signal,

wherein the amplification unit is structured to receive the isolated pilot control signal and the isolated voltage and to use the isolated pilot control signal and the isolated voltage to generate the pilot signal, and wherein the pilot signal is isolated from the power lines of the electric vehicle supply equipment.

2. The electrical circuit of claim 1, wherein the pilot control signal isolation unit includes an optocoupler structured to provide isolation for the isolated pilot control signal from the power lines of the electric vehicle supply equipment.

3. The electrical circuit of claim 2, wherein the optocoupler provides at least 6 kV of surge protection between the isolated pilot control signal and the power lines of the electric vehicle supply equipment.

4. The electrical circuit of claim 2, wherein the pilot control signal isolation unit further includes a switch structured to turn on when the pilot control signal has the low state and to turn off when the pilot control signal has the high state.

5. The electrical circuit of claim 4, wherein the switch is a transistor including a base, a common, and an emitter, wherein the pilot control signal isolation unit further includes a first resistor electrically connected to the pilot control signal unit, a second resistor electrically connected between the base and the emitter, and third and fourth resistors electrically connected in parallel between the common and the optocoupler.

6. The electrical circuit of claim 1, wherein the amplification unit further includes first and second resistors arranged as a voltage divider electrically connected to outputs of the a pilot control signal isolation unit.

7. The electrical circuit of claim 6, wherein the voltage divider is structured to receive the isolated voltage and to divide the isolated voltage when the pilot control signal has the high state.

8. The electrical circuit of claim 6, wherein the first and second resistors are high precision resistors.

9. The electrical circuit of claim 6, wherein the amplification unit includes an amplifier circuit structured to receive and amplify an output of the voltage divider.

10. The electrical circuit of claim 9, wherein the output of the amplifier circuit is −

12V when the pilot control signal has the low state and 12V when the pilot control signal has the high state.

11. The electrical circuit of claim 9, wherein the amplifier circuit includes an amplifier having a non-inverting input, an inverting input, and an output, a third resistor electrically connected between the voltage divider and the non-inverting input, a fourth resistor electrically connected between the inverting input and ground, and a fifth resistor and capacitor electrically connected in parallel between the inverting input and the output of the amplifier.

12. The electrical circuit of claim 9, wherein the amplification unit includes a conditioning circuit structured to condition the output of the amplification circuit and to output the pilot signal.

13. The electrical circuit of claim 12, wherein the conditioning circuit includes a sixth resistor and an inductor electrically connected in parallel, and wherein the conditioning circuit includes a transient voltage suppression diode electrically connected to ground.

14. The electrical circuit of claim 1, wherein when the pilot control signal has the low state, the isolated pilot control signal is −

12V and the pilot signal is −

12V.

15. The electrical circuit of claim 1, wherein when the pilot control signal has the high state, the isolated pilot control signal is 3V and the pilot signal is 12V.

16. The electrical circuit of claim 1 wherein when the pilot control signal has the high state, the pilot signal is a high precision 12V.

17. Electric vehicle supply equipment comprising:

power lines structured to carry power to charge an electric vehicle; and

a pilot signal generating circuit including;

a power supply unit structured to generate an isolated voltage that is isolated from the power lines;

a pilot control signal unit structured to generate a pilot control signal having a state including one of a high state and a low state;

a pilot control signal isolation unit structured to generate an isolated pilot control signal that is isolated from the power lines and is based on the state of the pilot control signal; and

an amplification unit structured to generate a pilot signal based on the state of the pilot control signal,

wherein the amplification unit is structured to receive the isolated pilot control signal and the isolated voltage and to use the isolated pilot control signal and the isolated voltage to generate the pilot signal, and wherein the pilot signal is isolated from the power lines.

18. The electric vehicle supply equipment of claim 17, wherein the pilot control signal isolation unit includes an optocoupler structured to isolate the pilot control signal from the power lines of the electric vehicle supply equipment.

19. The electric vehicle supply equipment of claim 18, wherein the optocoupler provides at least 6 kV of surge protection between the isolated pilot control signal and the power lines of the electric vehicle supply equipment.

20. The electric vehicle supply equipment of claim 17, wherein the amplification unit further includes first and second resistors arranged as a voltage divider electrically connected to outputs of the pilot control signal isolation unit, and wherein the voltage divider is structured to receive the isolated voltage and to divide the isolated voltage when the pilot control signal has the high state.

21. The electric vehicle supply equipment of claim 20, wherein the first and second resistors are high precision resistors.