OVERVOLTAGE PROTECTION IN A POWER SUPPLY

• US 20080266740A1
• Filed: 04/30/2007
• Published: 10/30/2008
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Smith, Robert B.
• Granted Patent: US 8,335,065 B2
• Time in Patent Office: Days
• US Class Current: 361/91.5
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A method for protecting against over voltage in a power supply comprises monitoring current amplitude and direction on an output connection of a power source that combines power from a plurality of power sources, and determining occurrence of a fault condition of the monitored power source based on the current amplitude and direction. In a fault condition of the monitored power source, operation of the monitored power source subject to the fault condition is terminated while continuing operation of the plurality of power sources exclusive of the monitored power source.

Claims

1. A method for protecting against over voltage in a power supply comprising:

monitoring current amplitude and direction at an output connection of a power source that combines power from a plurality of power sources; and

determining occurrence of a fault condition of the monitored power source based on the current amplitude and direction.

2. The method according to claim 1 further comprising:

in a fault condition of the monitored power source, terminating operation of the monitored power source subject to the fault condition while continuing operation of the plurality of power sources exclusive of the monitored power source.

3. The method according to claim 1 further comprising:

monitoring voltage at the output connection of the power source that combines power from the plurality of power sources; and

determining occurrence of a fault condition of the monitored power source based on an over-voltage condition prior to or simultaneously with the current amplitude and direction condition.

4. The method according to claim 1 further comprising:

determining the occurrence of the fault condition of the monitored power source for a current amplitude that exceeds a predetermined threshold current level.

5. The method according to claim 1 further comprising:

maintaining operation of the plurality of power sources exclusive of the monitored power source;

enabling replacement of the power source subject to the fault condition.

6. The method according to claim 1 further comprising:

combining power from the plurality of power sources by output-OR connections;

monitoring current amplitude and direction at a connection between the monitored power source and output-OR connections;

monitoring voltage amplitude at a connection between the output-OR connections and a load.

7. The method according to claim 1 further comprising:

combining power from the plurality of power sources by diode-OR connections, field-effect transistor (FET)-OR connections, or wired-OR connections; and

monitoring the current amplitude and direction at an anode connection of a diode, at a field-effect transistor, or at a wire coupled between the monitored power source and the connection between the plurality of power sources.

8. The method according to claim 7 further comprising:

configuring the diode-OR connections or the field-effect transistor (FET)-OR connections whereby a fault condition of the monitored power source that causes output voltage of the monitored power source to fall below a predetermined first threshold level causes the diode or the FET to disconnect the monitored power source subject to the fault condition from connection to the plurality of power sources; and

configuring the diode-OR connection or the FET-OR connection whereby a fault condition of the monitored power source that causes output voltage of the monitored power source to increase above a predetermined second threshold level causes the diode or the FET to pass the output voltage to the connection of the plurality of power sources, the plurality of power sources exclusive of the monitored power source collectively reducing output voltage and output current.

9. The method according to claim 7 further comprising:

monitoring voltage amplitude and current amplitude and direction at an anode terminal of a diode coupled to the output connection of the monitored power source;

monitoring common mode voltage at a cathode terminal of the diode;

determining absence of a fault condition for an anode-to-cathode voltage that is less than a predetermined threshold voltage and the anode current amplitude is less than a predetermined threshold current; and

determining a fault condition for an anode-to-cathode voltage that is greater than the predetermined threshold voltage.

10. The method according to claim 9 further comprising:

monitoring the voltage amplitude and current amplitude and direction at the anode terminal of the diode with respect to a first upper limit for detecting a source internal over-voltage and over-current limit that determines status of the monitored power source; and

monitoring the voltage amplitude and current amplitude and direction at the anode terminal of the diode with respect to a second upper limit that is higher than the first upper limit for detecting a system failure.

11. Control logic configured for protecting against over voltage in a power supply comprising:

a current sensor coupled to an output connection of a monitored power source that combines output power with a plurality of power sources, the current sensor configured for monitoring current amplitude and direction sourced by the monitored power source; and

a power controller coupled to the current sensor for receiving a current signal indicative of output power of the monitored power source and coupled to the monitored power source for transmitting a power control signal, the power controller comprising a logic that determines occurrence of a fault condition of the monitored power source based on the current amplitude and direction, and in a fault condition of the monitored power source, terminating operation of the monitored power source subject to the fault condition while continuing operation of the plurality of power sources exclusive of the monitored power source.

12. The control logic according to claim 11 further comprising:

a voltage sensor coupled to the output connection of the monitored power source that combines output power with a plurality of power sources, the voltage sensor configured for monitoring voltage at the output connection of the power source that combines power from the plurality of power sources; and

the power controller determining occurrence of a fault condition of the monitored power source based on an over-voltage condition prior to or simultaneously with the current amplitude and direction condition.

13. The control logic according to claim 11 further comprising:

the power controller comprising a logic that determines occurrence of the fault condition of the monitored power source when current amplitude that exceeds a predetermined threshold current level.

14. The control logic according to claim 11 further comprising:

an output ORing element coupled to the current sensor and configured to combine power from the plurality of power sources whereby a fault condition of the monitored power source that causes output voltage of the monitored power source to fall below a predetermined first threshold level causes the output ORing element to disconnect the monitored power source subject to the fault condition from connection to the plurality of power sources and configured whereby a fault condition of the monitored power source that causes output voltage of the monitored power source to increase above a predetermined second threshold level causes the output ORing element to pass the output voltage to the connection of the plurality of power sources, the plurality of power sources exclusive of the monitored power source collectively reducing output voltage and output current.

15. The control logic according to claim 11 further comprising:

an output ORing element coupled to the current sensor and configured to combine power from the plurality of power sources;

a voltage sensor coupled between the output ORing element and a load; and

the power controller comprising a logic that monitors current amplitude and direction at the current sensor and monitors common node voltage at the voltage sensor and determines absence of a fault condition for a voltage that is less than a predetermined threshold voltage and a current amplitude that is less than a predetermined threshold current and determines a fault condition for the voltage that is greater than the predetermined threshold voltage.

16. The control logic according to claim 15 further comprising:

the power controller comprising a logic that monitors current amplitude and direction at the current sensor with respect to a current upper limit for detecting a source internal over-current limit that determines status of the monitored power source and monitors voltage amplitude at the voltage sensor with respect to a voltage upper limit for detecting a system failure.

17. A power supply comprising:

at least one power source comprising;

a power input interface;

a pulse width modulator (PWM) switch coupled to the power input interface for receiving input power;

a current sensor coupled to the PWM switch and configured for monitoring current amplitude and direction from the PWM switch;

an output power ORing element coupled to the PWM switch and configured for combining output power with a plurality of power sources for supplying combined power to a load; and

a power controller coupled to the current sensor for receiving a current signal indicative of output power from the PWM switch and coupled to the PWM switch for transmitting a power control signal, the power controller comprising a logic that determines occurrence of a fault condition of the monitored power source based on the current amplitude and direction, and in a fault condition of the monitored power source, terminating operation of the monitored power source subject to the fault condition while continuing operation of the plurality of power sources exclusive of the monitored power source.

18. The power supply according to claim 17 further comprising:

the at least one power source further comprising;

a voltage sensor coupled to the output connection of the monitored power source that combines output power with a plurality of power sources, the current sensor configured for monitoring voltage at the output connection of the power source that combines power from the plurality of power sources; and

the power controller determining occurrence of a fault condition of the monitored power source based on an over-voltage condition prior to or simultaneously with the current amplitude and direction condition.

19. The power supply according to claim 17 further comprising:

a voltage sensor coupled between the output power ORing element and the load and configured for monitoring voltage amplitude of combined power supplied to the load.

20. The power supply according to claim 17 further comprising:

a filter coupled between the pulse width modulator (PWM) switch and the current sensor that filters power spikes from the power input interface and the PWM switch.

21. The power supply according to claim 17 further comprising:

the power controller comprising a logic that determines occurrence of the fault condition of the monitored power source when current amplitude that exceeds a predetermined threshold current level.

22. The power supply according to claim 17 further comprising:

the output ORing element configured to combine power from the plurality of power sources whereby a fault condition of the monitored power source that causes output voltage of the monitored power source to fall below a predetermined first threshold level causes the output ORing element to disconnect the monitored power source subject to the fault condition from connection to the plurality of power sources and configured whereby a fault condition of the monitored power source that causes output voltage of the monitored power source to increase above a predetermined second threshold level causes the output ORing element to pass the output voltage to the connection of the plurality of power sources, the plurality of power sources exclusive of the monitored power source collectively reducing output voltage and output current.

23. The power supply according to claim 17 further comprising:

a voltage sensor coupled between the output ORing element and a load; and

the power controller comprising a logic that monitors current amplitude and direction at the current sensor and monitors common node voltage at the voltage sensor and determines absence of a fault condition for a voltage that is less than a predetermined threshold voltage and a current amplitude that is less than a predetermined threshold current and determines a fault condition for the voltage that is greater than the predetermined threshold voltage.

24. The power supply according to claim 23 further comprising:

the power controller comprising a logic that monitors current amplitude and direction at the current sensor with respect to a current upper limit for detecting a source internal over-current limit that determines status of the monitored power source and monitors voltage amplitude at the voltage sensor with respect to a voltage upper limit for detecting a system failure.