Electric power conversion systems – Current conversion – Having plural converters for single conversion
Reexamination Certificate
1999-12-01
2001-08-21
Sterrett, Jeffrey (Department: 2838)
Electric power conversion systems
Current conversion
Having plural converters for single conversion
C363S021150
Reexamination Certificate
active
06278624
ABSTRACT:
THE FIELD OF THE INVENTION
The present invention generally relates to a high availability DC power supply, and more particularly, to a high availability DC power supply with multiple isolated inputs coupled to a common DC output power bus, wherein upon loss of one or more isolated inputs, the DC output power bus is still available to supply power.
BACKGROUND OF THE INVENTION
Businesses rely on a network of critical systems (e.g., computer and telephone systems) for everyday operation. Such systems are commonly utilized for storing and accessing information, communication, or manufacturing purposes. Most of these critical systems require a constant supply of direct current (DC) power to operate. Loss of power provided by a DC power supply to a critical system may result in failure of a business to be able to perform day to day operations.
A DC power supply receives a power input from an alternating current (AC) or DC power source, and provides a DC power output at a voltage required by the critical system. DC power supplies are designed to be capable of receiving power from multiple AC or DC sources in order to increase reliability by maintaining a constant supply of power. Such systems often require complex control or switching schemes in order to switch from one power source to another if one of the power sources is unavailable (e.g., due to a power failure). Often times the switching and control systems are very costly and/or very complex to operate.
One known DC power supply is capable of receiving multiple AC power inputs. The independent sources of power may have grounds which are not at the same potential, and as such, must be maintained in isolation from each other. The DC power supply includes a transformer for each separate AC power input, and control technology on both the primary and secondary side of each transformer. Complex isolation technology is provided on the secondary side of the transformer in order to maintain isolation of the separate power supply inputs. The duplication of technology on both the primary and secondary side of each transformer may result in a costly and complex DC power supply system.
SUMMARY OF THE INVENTION
The present invention is a high availability DC power supply with isolated inputs and a common DC output power bus. The isolated inputs can be coupled to independent AC and DC power sources wherein the output power bus is still available to supply power upon the loss of one or more of the input power sources.
In one embodiment, the present invention provides a high availability power supply. The power supply includes a first diode having a first diode output, and a second diode having a second diode output. A first isolated direct current power supply is coupled to the first diode. A second isolated direct current power supply is coupled to the second diode. An output power bus is defined by the first diode output coupled to the second diode output, wherein the output power bus is still available to supply power upon the loss of the first isolated direct current power supply or the loss of the second isolated direct current power supply.
In one aspect, the first isolated direct current power supply includes a first isolating transformer having a first direct current power source input. The second isolated direct current power supply includes a second isolating transformer having a second direct current power source input. The second direct current power source input is different from the first direct current power source input. In one aspect, the first isolating transformer is an isolating fly-back transformer. The first direct current power source input includes an alternating current power source input coupled to an AC to DC converter.
In one aspect, the first isolated direct current power supply is a voltage regulated power supply and the second isolated direct current power supply is a voltage regulated power supply. The power supply may further include a first feedback control loop coupled to the first isolated current power supply and a second feedback control loop coupled to the second isolated direct current power supply for maintaining a desired voltage at the output power bus.
In one aspect, the power supply includes a power factor correction system coupled to the first feedback control loop. The first diode is a high speed, fast recovery diode of appropriate voltage and rating.
In another embodiment, the present invention provides a high availability power supply. The high availability power supply includes a first diode having a first diode output. A second diode is provided having a second diode output. A first isolated direct current power supply is provided including a first isolating transformer coupled to the first diode. A second isolated direct current power supply is provided including a second isolating transformer coupled to the second diode. An output power bus is provided defined by the first diode output coupled to the second diode output. The output power bus maintains its availability to supply power upon the loss of the first isolated direct current power supply with the lose of the second isolated direct current power supply.
In one aspect, a first feedback control loop is coupled to the first isolated direct current power supply and a second feedback control loop is coupled to the second isolated direct current power supply for maintaining a desired voltage at the output power bus. A power factor correction system is coupled to the first feedback control loop.
In one aspect, the first isolating transformer is an isolating fly-back transformer. The first direct current power supply includes an alternating current power source coupled to an AC to DC converter. A voltage regulation control system is coupled to the first isolated direct current power supply. A first feedback control loop is coupled to the voltage regulation control system. A power factor correction system is coupled to the first isolated direct current power supply.
In one aspect, the first diode is a high speed, fast recovery diode and the second diode is a high speed, fast recovery diode.
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Hewlett--Packard Company
Sterrett Jeffrey
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