Patent Application
20100019575
Power distribution units (“PDUs”) are typically used in systems wherein a plurality of electrical power outlets are needed. The outlets may provide a variety of voltages and current capabilities, or may all be the same. Examples of use of a PDU include computer rooms, network rooms or cabinets, hospital operating rooms, communications systems, military installations, manufacturing facilities and many others. Often times a power distribution unit receives a high power electrical feed from a central supply, the PDU then providing a plurality of power outlets (sometimes denominated “power ports”) in parallel, allowing individual loads to be connected to certain outlets which provide electrical power appropriate for the individual load. Typically a PDU is provided with a circuit breaker protecting the entire unit, and the PDU may be turned ON or OFF, either physically or remotely. An individual outlet may also be individually provided with certain other features, such as a ground fault interrupt (“GFI”) unit, special noise filtering, noise suppression, surge protection, or other features desired for a given load.
In the prior art a plurality of PDUs are deployed geographically. That is, each PDU is physically placed near where it is used. However the various loads connected to a given PDU may have very diverse uses. For example, a facility may have a PDU providing power for a computer cabinet, cooling equipment, safety equipment, lighting, security alarms, and other diverse loads. In some systems provision is made in the PDU for remote control and/or monitoring. The remote provision can include the ability to control or monitor a PDU via a local area network. If the local area network includes a gateway to the internet, the PDU may also include the capability for remote control and monitoring that may be accomplished from literally anywhere in the world.
Control and monitoring systems provide the means for management of a plurality of PDUs, including control and monitoring from a central location. However each PDU is treated in the same way it is deployed: as a whole unit. Programming of functions, for example lighting schedules and entry/egress gate power schedules, requires the user to keep track of the assignment of each power outlet of each PDU, where the PDU is, what load is assigned and other information, making it difficult to comprehend and control all of the loads correctly and efficiently.
What is needed is a method for managing the various loads, or category of loads, powered by individual PDU power outlets without regard to the specific PDU within which a power outlet is physically incorporated. It is also desirable to be able to determine aggregate use and characteristics of a collection of power outlets that are not physically instantiated within a common PDU.
The present invention provides a method for creating a virtual PDU, or “VPDU”, wherein a VPDU is comprised of a plurality of physical power outlets from a plurality of individual PDUs, the outlets logically combined and managed as though the VPDU were a single physical PDU. A VPDU is comprehended by a user or controller in the same manner as it is with a conventional or so-called “real” PDU. However the various outlets of a VPDU may be located anywhere in the world to which a central controller has signal access, such as via a LAN or an internet connection. The VPDU is “created” by using systems and software according to the present invention, wherein a user selects disparate individual PDU outlets to be associated with a certain collection. The collection may then be managed by the user exactly as the user would normally manage a single physical PDU. That is, as with a physical PDU, a VPDU may be managed as a single unit, or a subset of the outlets associated with the VPDU may be managed individually. Additionally, characteristic and use data may be collected for the VPDU or a subset of the VPDU, much as it is available in a typical PDU. For example, all interior lights of a campus may be logically mapped by software to a single VPDU, thereafter the entire VPDU scheduled for times at which the interior lights are to be turned ON or OFF. In some embodiments PDUs provide means for measuring and reporting power characteristics such as peak current, over or under voltage, tripped circuit breakers, watt-hours used and other data which a VPDU then reports as though the individual reports and the aggregate of them were related to a real PDU comprised of the outlets that were previously selected to be associated with the VPDU.
In an example illustrative of the utility of the present invention, consider a VPDU defined as a collection of electrical outlets powering HVAC air conditioning equipment deployed across an industrial campus, each air conditioning unit powered by a different physical PDU. The facility may have negotiated a lower electrical power rate from its power provider by agreeing to allow the power provider to turn OFF power to the HVAC air conditioning equipment for a certain period of time on days in which the power provider has inadequate capacity, such as during a heat wave in the area. The power provider is provided with the ability to turn the power provided to the air conditioning equipment ON or OFF remotely via an internet connection. Similarly the lights of a facility may be virtually incorporated into a “lights VPDU” and a schedule provided by the user to turn OFF certain lights while leaving others ON during a power outage or an emergency, such as a fire. In one embodiment of the present invention a critical electrical appliance is provided power from two or more separate physical PDUs for power redundancy. A VPDU defined as the two or more outlets providing power to the common appliance may be turned ON or OFF, thereby turning all outlets ON or OFF simultaneously. One skilled in the art will know of many other scenarios of utility for the present invention.
In the example of
In some embodiments control of the plurality of PDUs is mixed. That is, a given PDU may be locally controlled, either by a LAN connection or pushing buttons, and the same PDU controlled as a member of a VPDU, whether the entire PDU or a subset of the PDU power outlets is incorporated into the VPDU.
For ease of description and clarity of understanding, the method of the present invention will be described as embodied in software or firmware executed by the controller 308. Continuing to look to
From the two PDUs 302, 304 a variety of VPDUs may be defined and used. For example, outlets 310.0 and 312.0 supply redundant power to a network server. By combining the two outlets as a VPDU a control system 340 may turn power to the network server 322 ON or OFF with a single command. If one of the outlets 310.0, 312.0 fails or a circuit breaker in one of the PDUs 302, 304 opens, the other outlet (310.0 or 312.0) provides power to the network server 322 and in one embodiment the failing or the non-failing outlet reports the failure to the controller 308. Another VPDU may be defined combining the outlets providing power to a light circuit 326 and a light circuit 324 (powered by outlets 312.1 and 310.1 respectively), enabling a report of energy used for lighting. These are simply two arbitrary examples of how power outlets in physically separate PDUs may be logically associated for the purposes of control and monitoring. Of course a plurality of outlets on a single, common PDU may also be associated to form a VPDU.
In some embodiments of the present invention “virtual circuit breakers” are created, wherein current limits are specified for a certain outlet or outlet set, then the outlet(s) disabled whenever the instant current value reported by the PDU is in excess of the predetermined maximum current value for a predetermined period of time. Similarly, high and/or low current limits may be predetermined and reports provided to the controller 308 when such limits are exceeded. For example, a low current limit for a specified outlet may be used to determine if the load connected to the outlet has failed or if the load has been unplugged from the PDU power outlet. Note that a collection of PDUs may be accessed by multiple controllers 308. A given outlet may also be defined as part of a VPDU on more than one VPDU/control system 340. Depending upon the design of a PDU, monitoring of current or other conditions and taking action upon an out-of-specification condition may be performed by the PDU itself with reporting of the action to the controller 308, or the PDU may only report the condition and the control console 308 takes action, for example by commanding that an outlet be turned OFF.
Management of a given power outlet may be ON and OFF control only, the monitoring of certain characteristics or states only, or both. Management of a collection of physical assets combined to form a VPDU is largely a database management procedure. The following description illustrates one embodiment of such a database management structure with procedures, though one skilled in the art will know of many alternative database management techniques equally able to embody the method of the present invention, which are within the scope of the present invention. The database is described as fields with records, however a control program associated with, for example, a computer may display certain database tables to a viewer as folders with subfolders, files, and the like. Consider
A display console 310 may display the data of the table in
As stated hereinbefore, control of a VPDU may be implemented as a computer program, embedded firmware, custom logic, or other means for managing data, such as state variables. For clarity,
In the example of
The details of control flow 700 vary, depending upon the design of the controller and the resources provided by each PDU and PDU outlet. For example, some embodiments do not include a handshake or return response.
