Capacitive power system having a service life extending approach

• US 9,379,577 B2
• Filed: 08/30/2012
• Issued: 06/28/2016
• Est. Priority Date: 08/30/2012
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Stupka, Radek
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Vu, Toan
• Application Number:
  US13/599,953
• Publication Number:
  US 20140062200A1
• Time in Patent Office: 1,398 Days
• Field of Search: 307/64
• US Class Current: 1/1
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/00 Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting

Abstract

A capacitive power system having a service life extending approach. The system may have an ultra or super capacitor with high capacitance. A predetermined amount of energy may be stored in the capacitor, sufficient for providing power to an electrically powered mechanism in the event the mechanism loses its power, to place it in a fail safe condition. With the capacitor at an initial capacitance, the working voltage may be set as low as possible while still retaining sufficient capacity for storing the predetermined amount of energy. As the capacitor'"'"'s capacitance decreases with age, the working voltage of the capacitor may be gradually increased to compensate for lost capacitance. If the mechanism loses power, then a discharge of the capacitor may be initiated to transfer energy to the mechanism. If the electrical mechanism has power, then a charging of the capacitor may be initiated to transfer energy to the capacitor.

Claims

1. A system having a service life extender for a capacitor, comprising:

a power module connected to a capacitor; and

a diagnostics module connected to the power module; and

wherein;

the diagnostics module determines a minimum working voltage of the capacitor

needed for storing a predetermined amount of energy;

the power module controls current and voltage at the capacitor;

the predetermined amount of energy is sufficient for providing a failsafe condition for an electrical mechanism if a power-off condition to the electrical mechanism is detected;

if the capacitor is determined to be insufficient to store the predetermined amount of energy at the minimum working voltage, then the minimum working voltage is increased to provide energy storage sufficient to store the predetermined amount of energy;

the diagnostics module continuously measures a voltage at the capacitor and determines whether the voltage is equal to or greater than the minimum working voltage needed for storing the predetermined amount of energy;

if the voltage is equal to or greater than the minimum working voltage, then a charge cycle is not needed;

if the voltage is less than the minimum working voltage and the power-on condition is detected, then a charge cycle is initiated and continued until the voltage is equal to or greater than the minimum working voltage plus a hysteresis voltage; and

if a power-off condition is detected, then a discharge cycle is initiated and energy is transferred from the capacitor to an electrical mechanism to provide the fail safe condition for the electrical mechanism.

2. The system of claim 1, further comprising:

a monitor connected to the power module; and

wherein;

the monitor detects a power-on or power-off condition of the electrical mechanism.

3. The system of claim 1, wherein:

the electrical mechanism is an actuator; and

the failsafe condition is a position of a damper or valve controlled by the actuator, placed in a safe power-off position.

4. The system of claim 2, wherein the capacitor has a capacitance of one or more farads.

5. The system of claim 2, wherein the minimum working voltage of the capacitor, needed to store the predetermined amount of energy, is increased as necessary to compensate for decreased capacitance of the capacitor due to deterioration.

6. A method for expanding a service life of a capacitor, comprising:

providing a capacitor for storing a predetermined amount of energy;

providing an electrical mechanism that uses the predetermined amount of energy from the capacitor to achieve a failsafe condition if the mechanism loses power;

determining the predetermined amount of energy needed to place the electrical mechanism in the failsafe condition if the electrical mechanism loses power;

initiating a discharge cycle of the capacitor to transfer the predetermined amount of energy from the capacitor to the electrical mechanism to achieve the failsafe condition when the mechanism loses power;

periodically determining a minimal working voltage of the capacitor needed to store the predetermined amount of energy in the capacitor;

increasing or decreasing the minimal working voltage to be merely sufficient for the capacitor to store the predetermined amount of energy;

wherein;

the capacitor has a capacitance sufficient to store X times the predetermined amount of energy; and

X≧

1.

7. The method of claim 6, further comprising initiating a charge cycle of the capacitor to transfer energy from the electrical mechanism to the capacitor as needed to store the predetermined amount of energy when the electrical mechanism has power.

8. The method of claim 6, further comprising:

periodically measuring voltage at the capacitor; and

wherein;

if the voltage is less than the minimal working voltage, then transfer energy from the electrical mechanism to the capacitor; and

if the voltage is equal to or greater than the minimal working voltage plus a hysteresis voltage, then stop transferring energy from the electrical mechanism to the capacitor.

9. The method of claim 6, further comprising:

determining the normal rated working voltage of the capacitor; and

implementing the capacitor at a minimum working voltage that is Y times the normal rated working voltage of the capacitor, wherein Y≦

1.

10. The method of claim 9, wherein the capacitor is a super capacitor having a value greater than one farad.

11. The method of claim 9, wherein:

the electrical mechanism is an actuator; and

the fail safe condition is a position of a damper or valve controlled by the actuator, placed in a safe position.

12. A capacitive power source having a service life extending approach, comprising:

a capacitor control block connected to the capacitor module; and

a diagnostics module connected to the capacitor control block; and

wherein;

the capacitor module comprises a capacitor;

the capacitor is operated at a minimum working voltage which is less than a maximum rated working voltage of the capacitor;

the diagnostics module determines the minimum working voltage for storing a predetermined amount of energy; and

the predetermined amount of energy is for providing a failsafe condition for an electrical mechanism in an event of a power-off condition of the electrical mechanism.

13. The system of claim 12, wherein the minimum working voltage of the capacitor is increased as needed to compensate for decreased energy storage of the capacitor occurring over time.

14. The system of claim 12, wherein:

the capacitor control block further comprises a monitor and a power module connected to the diagnostics module;

the monitor provides a signal to the diagnostics module when detecting the power-off condition of the electrical mechanism; and

the power module controls current and voltage at the capacitor module for providing and/or receiving energy.

15. The system of claim 14, wherein:

the power module is for receiving and providing energy and is connected to the electrical mechanism; and

the power module provides backup energy when the electrical mechanism has a power-off condition, to place the electrical mechanism in a fail safe condition.

16. The system of claim 15, wherein:

the electrical mechanism is an actuator; and

the fail safe condition is a safe position of a damper or valve when the actuator has a power-off condition.

17. The system of claim 12, wherein the capacitor is a super capacitor having a capacitance of one or more farads.