Electrical transmission or interconnection systems – Plural load circuit systems – Plural sources of supply
Reexamination Certificate
1999-08-26
2001-03-13
Riley, Shawn (Department: 2838)
Electrical transmission or interconnection systems
Plural load circuit systems
Plural sources of supply
C307S066000
Reexamination Certificate
active
06201319
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a method and apparatus for providing uninterruptible, regulated power to critical and/or sensitive loads. More specifically, the present invention relates to a modular uninterruptible power supply (UPS) having redundant systems to prevent single point failures and to ensure power system availability for the critical and/or sensitive loads.
DISCUSSION OF THE RELATED ART
The use of uninterruptible power supplies having battery back-up systems to provide regulated, uninterrupted power for sensitive and/or critical loads, such as computer systems, and other data processing systems is well known.
FIG. 1
shows a typical prior art UPS
10
used to provide regulated uninterrupted power. The UPS
10
includes an input circuit breaker/filter
12
, a rectifier
14
, a control switch
15
, a controller
16
, a battery
18
, an inverter
20
and an isolation transformer
22
. The UPS also includes an input
24
for coupling to an AC power source and an outlet
26
for coupling to a load.
The UPS
10
operates as follows. The circuit breaker/filter
12
receives input AC power from the AC power source through the input
24
, filters the input AC power and provides filtered AC power to the rectifier
14
. The rectifier converts the filtered AC power to DC power having a -predefined voltage value. The control switch
15
receives the DC power from the rectifier and also receives DC power from the battery
18
. The controller
16
determines whether the DC power available from the rectifier is within predetermined tolerances, and if so, controls the control switch to provide the DC power from the rectifier to the inverter
20
. If the DC power from the rectifier is not within the predetermined tolerances, which may occur because of “brown out” or “black out” conditions, or due to power surges, then the controller controls the control switch to provide the DC power from the battery
18
to the inverter
20
.
The inverter
20
of the prior art UPS
10
receives DC power from the controller
16
, converts the DC power to AC power, and regulates the AC power to predetermined specifications. The inverter
20
provides the regulated AC power to the isolation transformer
22
. The isolation transformer is used to increase or decrease the voltage of the AC power from the inverter and to provide electrical isolation between a load and the UPS. Depending on the capacity of the battery and the power requirements of the load, the UPS
10
can provide power to the load during brief power source “dropouts” or for extended power outages.
In some prior art systems, the controller, the control switch and/or the battery may also contain circuitry to charge the battery using the DC power supplied by the rectifier. In addition, in some prior art systems, the controller provides operating status information to a user, either locally using, for example, indicating lights or a display system, or remotely by communicating with an external monitoring device.
There are several drawbacks associated with the prior art system shown in FIG.
1
. First, the system shown in
FIG. 1
is not scalable to accommodate increases in load power requirements. In typical data processing facilities that utilize UPS's, the power requirements typically increase over time as data processing equipment is expanded or upgraded, and if the UPS is not expandable, then it is often times replaced with a larger, more expensive model. Second, typical prior art UPS's have several single point failure mechanisms, the occurrence of which may disable the UPS and leave the load susceptible to power disturbances.
One prior art UPS system, disclosed in U.S. Pat. No. 5,694,312 to Brand et al., provides a modular system to accommodate changing load requirements. However, the system disclosed in Brand et al., like the prior art system
10
, has several single point failure mechanisms which reduces the availability, of the UPS, and therefore, reduces the power protection provided to the load. In particular, a failure of the control circuitry in either the UPS
10
, described above, or in the UPS system disclosed by Brand et al., may result in a complete failure of the UPS.
SUMMARY OF THE INVENTION
Embodiments of the present invention overcome the drawbacks of the prior art by providing a fully scalable, modular UPS system with redundant control circuitry to increase the availability of the UPS, and reduce the UPS system's susceptibility to single point failures.
In one general aspect, the invention features a power supply system including a power input to receive input power from a power source, a power output to provide output power to a load, at least one battery module having a battery output that provides battery power, at least one power module coupled to the power input to receive the input power, coupled to the battery output to receive the battery power and coupled to the power output to provide the output power, a controller constructed and arranged to monitor and control the output power from the at least one power module, and a redundant controller, coupled to the at least one power module and to the controller, constructed and arranged to provide redundant monitoring and controlling of the output power from the at least one power module.
The redundant controller can be constructed and arranged to monitor and control the output power from the at least one power module upon failure of the controller. The at least one power module, the controller and the redundant controller can be constructed and arranged such that one of the controller and the redundant controller regulates the output power from the at least one power module. The at least one power module, the controller and the redundant controller can be constructed and arranged such that one of the controller and the redundant controller provides phase synchronization for the output power from the at least one power module. The at least one power module can include circuitry to regulate the output power to predetermined levels. The controller and the redundant controller can be constructed and arranged to allow the redundant controller to monitor operation of the controller, and to assume control of the at least one power module upon detection of a fault in the controller. The controller can include a main processor and a slave processor coupled to the main processor, the redundant controller can include a redundant processor coupled to the main processor in the controller, and the main processor can be constructed and arranged to determine an operational state of the power supply system and to provide control signals to the slave processor and the redundant processor indicative of the operational state. The slave processor can be substantially identical to the redundant processor. The power supply system can include control lines from the controller to the at least one power module and control lines from the redundant controller to the at least one power module, and the at least one power module can be constructed and arranged to respond to either the control lines from the controller or the control lines from the redundant controller based on operational states of the controller and the redundant controller. The at least one power module can be a plurality of power modules and the at least one battery can be a plurality of batteries. Each of the power modules can be constructed and arranged to select one of the battery power or the input power as a source for generating the output power.
In another general aspect, the invention features a power supply system that includes a power input to receive input power from a power source, a power output to provide output power to a load, at least one battery module having a battery output that provides battery power, means for generating the output power using one of the input power and the battery power, means for monitoring and controlling the output power generated by the means for generating, and redundant means for monitoring and controlling the output power genera
Charlantini Donald L.
Colucci David A.
Ingemi Michael J.
Klikic Damir
Simonelli James M.
American Power Conversion
Mintz Levin Cohn Ferris Glovsky and Popeo P.C.
Riley Shawn
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