Isolation barrier fault detection circuit

• US 10,161,981 B2
• Filed: 09/14/2016
• Issued: 12/25/2018
• Est. Priority Date: 09/14/2016
• Status: Active Grant

• Current Assignee: CPS Technology Holdings, LLC
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Dulle, Ronald J., Johnson, Mark R.
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): Monsur, Nasima
• Application Number:
  US15/265,556
• Publication Number:
  US 20180074107A1
• Time in Patent Office: 832 Days
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: G01R 27/025 Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/364 Battery terminal connectors with integrated measuring arrangements
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An energy storage system may include one or more battery packs, wherein one terminal of the one or more battery packs is electrically coupled to a resistor representative of an isolation resistance of the energy storage system, a semiconductor relay switch, a plurality of resistors configured to electrically couple to the one or more battery packs via the semiconductor relay switch, a gain field-effect transistor (FET) configured to electrically short at least one resistor of the plurality of resistors, one or more capacitors electrically couples to a system ground of a vehicle and the one or more battery packs, and a control system configured to control the semiconductor switch and the gain FET.

Claims

1. An energy storage system configured to output at least two voltage waveforms, comprising:

a semiconductor relay switch;

one or more battery packs, wherein one terminal of the one or more battery packs of the energy storage system is electrically coupled to a resistor of a plurality of resistors, wherein the plurality of resistors is configured to electrically couple to the one or more battery packs via the semiconductor relay switch;

a gain field-effect transistor (FET) configured to electrically short at least one resistor of the plurality of resistors, wherein the at least one resistor of the plurality of resistors is electrically coupled in parallel to the gain FET and is directly coupled to a voltage output terminal configured to output the at least two voltage waveforms for determining an isolation resistance of the energy storage system;

one or more capacitors electrically coupled to a system ground of a vehicle and the one or more battery packs; and

a control system configured to control the semiconductor switch and the gain FET.

2. The energy storage system of claim 1, wherein the one or more battery packs comprise one or more lead acid battery packs or one or more lithium ion battery packs.

3. The energy storage system of claim 1, wherein the semiconductor relay switch comprises a light-emitting diode as an input and a metal-oxide-semiconductor field-effect transistor (MOSFET) as an output.

4. The energy storage system of claim 1, wherein the semiconductor relay switch comprises a PhotoMOS switch.

5. The energy storage system of claim 1, wherein the gain FET is configured to electrically couple to the system ground.

6. The energy storage system of claim 1, wherein the gain FET comprises a 200 voltage amplifier device.

7. The energy storage system of claim 1, comprising a first switch configured to electrically couple a first resistor to the one or more battery packs and a second switch configured to electrically couple a second resistor to the one or more battery packs, wherein the first resistor and the second resistor of the energy storage system.

8. The energy storage system of claim 1, wherein the one or more capacitors comprise one or more Y class capacitors configured to suppress electromagnetic interference.

9. A system, comprising:

a chassis; and

an energy storage system configured to monitor an isolation resistance between the energy storage system and the chassis, wherein the energy storage system comprises;

a semiconductor relay switch;

one or more battery packs, wherein one terminal of the one or more battery packs of the energy storage system is electrically coupled to a resistor of a plurality of resistors, wherein the plurality of resistors is configured to electrically couple to the one or more battery packs via the semiconductor relay switch;

a gain field-effect transistor (FET) configured to electrically short at least one resistor of the plurality of resistors, wherein the at least one resistor of the plurality of resistors is electrically coupled in parallel to the gain FET and is directly coupled to a voltage output terminal configured to output a voltage waveform for determining an isolation resistance between the energy storage system and the chassis;

one or more capacitors electrically coupled to a system ground and the one or more battery packs; and

a control system configured to control the semiconductor switch and the gain FET.

10. The system of claim 9, wherein the one or more battery packs comprise one or more lead acid battery packs or one or more lithium ion battery packs.

11. The system of claim 9, wherein the semiconductor relay switch comprises a light-emitting diode as an input and a metal-oxide-semiconductor field-effect transistor (MOSFET) as an output.

12. The system of claim 9, comprising a first resistor of the plurality of resistors electrically coupled to the one or more battery packs and the semiconductor relay switch.

13. The system of claim 12, comprising a second resistor of the plurality of resistors electrically coupled to the at least one resistor, the gain FET, the first resistor, and the semiconductor relay switch.

14. The system of claim 13, comprising a second gain FET electrically coupled to the system ground and a third resistor of the plurality of resistors, wherein the third resistor is electrically coupled to the at least one resistor and the gain FET.

15. The system of claim 14, comprising a fourth resistor of the plurality of resistors electrically coupled to the system ground, the third resistor, the at least one resistor, and the gain FET.

16. The system of claim 15, wherein the control system is configured to measure the voltage waveform corresponding to the isolation resistance via the voltage output terminal electrically coupled to the fourth resistor and the system ground.

17. An isolation measurement circuit for detecting an isolation barrier fault, comprising:

a semiconductor relay switch;

a plurality of resistors configured to electrically couple to one or more battery packs via the semiconductor relay switch, wherein one terminal of the one or more battery packs is electrically coupled to a resistor of the plurality of resistors of an energy storage system;

a gain field-effect transistor (FET) configured to electrically short at least one resistor of the plurality of resistors, wherein the at least one resistor of the plurality of resistors is electrically coupled in parallel to the gain FET and is directly coupled to a voltage output terminal configured to output a voltage waveform for determining an isolation resistance between the energy storage system and a chassis;

one or more capacitors electrically coupled to a system ground of a vehicle and the one or more battery packs; and

a control system configured to control the semiconductor switch and the gain FET.

18. The isolation measurement circuit of claim 17, wherein the semiconductor relay switch comprises light-emitting diode as an input and a metal-oxide-semiconductor field-effect transistor (MOSFET) as an output.

19. The isolation measurement circuit of claim 17, wherein the semiconductor relay switch comprises a PhotoMOS switch.

20. The isolation measurement circuit of claim 17, wherein the gain FET comprises a 200 voltage amplifier device.

21. The isolation measurement circuit of claim 17, comprising a first resistor of the plurality of resistors electrically coupled to the one or more battery packs and the semiconductor relay switch.

22. The isolation measurement circuit of claim 21, comprising a second resistor of the plurality of resistors electrically coupled to the at least one resistor, the gain FET, the first resistor, and the semiconductor relay switch.