Discrete energy reservoir with diagnostics

Patent metadata

Field	Value
Publication number	US-10014716-B2
Application number	US-201514978768-A
Country	US
Kind code	B2
Filing date	Dec 22, 2015
Priority date	Dec 22, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A backup power system in a vehicle that provides temporary power to one or more electronic control units (ECUs) upon failure of a main power supply. The backup power system includes an energy reservoir that stores electric charge. A charging circuit is electrically connected to the energy reservoir to generate charge for the energy reservoir during normal operation of the vehicle. A discharging circuit for supplying backup power is electrically connected between the energy reservoir and the ECUs. A diagnostic circuit is electrically connected to the energy reservoir and a microcontroller. The microcontroller is configured to monitor a slew rate of the energy reservoir as an amount of stored electric charge in the energy reservoir changes, determine if the slew rate is within a predetermined range, and when the slew rate is not within the predetermined range, generate a first error signal.

First claim

What is claimed is:

1. A backup power system in a vehicle that provides temporary power to at least one electronic control unit (ECU) upon failure of a main power supply, the backup power system comprising:
an energy reservoir that stores electric charge;
a charging circuit electrically connected to the energy reservoir;
a discharging circuit electrically connected between the energy reservoir and the at least one electronic control unit;
a diagnostic circuit electrically connected to the energy reservoir and configured to regulate a current flow for the energy reservoir;
an electronic processor communicatively coupled to the diagnostic circuit, the electronic processor configured to
monitor a change in a voltage over time of the energy reservoir as an amount of stored electric charge in the energy reservoir changes,
determine if the change in a voltage over time is within a predetermined range, and when the change in a voltage over time is not within the predetermined range,
generate a first error signal.

2. The backup power system of claim 1 , wherein the energy reservoir includes one or more capacitors and wherein the at least one electronic control unit is an airbag electronic control unit.

3. The backup power system of claim 1 , comprising: a constant current regulator included in the diagnostic circuit; a voltage detector that generates a voltage signal indicative of a voltage of the energy reservoir, the voltage detector electrically connected to the electronic processor; and a control switch actuated by the electronic processor, the control switch electrically connected between the constant current regulator and the energy reservoir.

4. The backup power system of claim 3 , wherein the constant current regulator regulates a current flow by setting a fixed amount of a charging current being supplied to the energy reservoir, and wherein the electronic processor determines a charging change in a voltage over time based on the voltage signal.

5. The backup power system of claim 4 , wherein the charging current flows from the charging circuit to the energy reservoir through the control switch based on actuation by the electronic processor.

6. The backup power system of claim 4 , wherein the charging change in a voltage over time is determined during initial charging of the energy reservoir, and wherein, after initial charging, the constant current regulator is bypassed allowing higher current and higher voltage charging of the energy reservoir.

7. The backup power system of claim 3 , wherein the constant current regulator regulates a current flow by setting a fixed amount of a discharge current during a discharge diagnostic cycle, and wherein the electronic processor determines a discharging change in a voltage over time based on the voltage signal.

8. The backup power system of claim 7 , wherein the discharge current flows from the energy reservoir to ground through the control switch based on actuation by the electronic processor.

9. The backup power system of claim 8 , wherein the voltage detector is a high-resistance voltage divider connected between a terminal on the energy reservoir and the electronic processor.

10. The backup power system of claim 1 , comprising: a boost switched-mode power supply included in the charging circuit, the boost switched-mode power supply configured to increase an input voltage level supplied to the energy reservoir from a vehicle battery.

11. The backup power system of claim 1 , comprising: a buck switched-mode power supply included in the discharging circuit, the buck switched-mode power supply configured to decrease an output voltage level supplied to the at least one electronic control unit from the energy reservoir.

12. A method of supplying temporary backup power to at least one electronic control unit in a vehicle upon failure of a main power supply, the method comprising:
charging an energy reservoir via a charging circuit;
storing an electric charge in the energy reservoir;
discharging at least part of the electric charge in the energy reservoir to the at least one electronic control unit upon failure of the main power supply;
regulating a current in a diagnostic circuit to maintain a constant current flow for the energy reservoir;
monitoring, with an electronic processor, a change in a voltage over time of the energy reservoir during a change of the stored electric charge in the energy reservoir;
determining, with the electronic processor, if the change in a voltage over time is within a predetermined range;
and when the change in a voltage over time is not within the predetermined range,
generate, with the electronic processor, a first error signal.

13. The method of claim 12 , comprising: detecting a voltage of the energy reservoir with the electronic processor; and determining the change in a voltage over time based on the constant current flow and the voltage of the energy reservoir.

14. The method of claim 13 , wherein the voltage is detected at predetermined intervals and wherein, the change in a voltage over time is determined at the predetermined intervals.

15. The method of claim 13 , comprising: setting a fixed amount of charging current being supplied to the energy reservoir via a charging current regulator, and determining a charging change in a voltage over time based on the voltage and the constant current flow.

16. The method of claim 13 , comprising actuating a control switch, via the electronic processor, to charge the energy reservoir with the constant current flow upon startup of the vehicle.

17. The method of claim 16 , comprising actuating the control switch, via the electronic processor when the energy reservoir reaches a predetermined voltage, and when the energy reservoir reaches the predetermined voltage, bypassing a constant current regulator.

18. The method of claim 13 , comprising: setting a fixed amount of discharge current via a discharging constant current regulator during a discharge diagnostic cycle, and determining, via the electronic processor, a discharging change in a voltage over time based on the voltage of the energy reservoir and the fixed amount of discharge current.

19. The method of claim 18 , comprising actuating a control switch, via the electronic processor, to electrically connect the energy reservoir to ground through the discharging constant current regulator during the discharge diagnostic cycle.

20. The method of claim 12 , wherein during failure of the main power supply, the energy reservoir supplies the at least one electronic control unit with power that enables the at least one electronic control unit to send critical messages from the at least one electronic control unit to other vehicle systems.

Assignees

• Bosch Gmbh Robert

Inventors

• Jawany Jalal
• Sydor Stephen P

Classifications

• G01R31/016

  Testing of capacitors (measuring capacitance G01R27/2605) · CPC title

• G01R31/007

  using microprocessors or computers · CPC title

• G01R31/392

  Determining battery ageing or deterioration, e.g. state of health · CPC title

• B60R16/03

  for supply of electrical power to vehicle subsystems {or for (circuit arrangements for charging batteries H02J7/00)} · CPC title

• H02J9/061 Primary

  for DC powered loads · CPC title