Patent Application
20200081504
The present disclosure relates generally to power systems in relation to a multi-load system. More particularly, aspects of this disclosure relate to load balancing to prevent imbalanced power outputs from a power system coupled to a phased current source.
The emergence of the cloud for computing applications has increased the demand for off-site installations, known as data centers, that store data and run applications accessed by remotely connected computer device users. Such data centers typically have massive numbers of servers, switches, and storage devices to store and manage data. A typical data center has physical rack structures with attendant power and communication connections. There are many such network devices stacked in such rack structures found in a modern data center. For example, some data centers have tens of thousands of servers, attendant storage devices, and network switches. Thus, a typical data center may include tens of thousands, or even hundreds of thousands, of devices in hundreds or thousands of individual racks.
Such devices require a large amount of power. Electronic devices generally use a three-phase power system supplying AC power. In three-phase power supply systems, AC power is supplied via three conductors. Each conductor supplies an alternating voltage signal of the same frequency, relative to a common reference, with a phase difference of one third of a cycle between each. Thus, each conductor is said to provide a different phase. The common reference is usually connected to ground and often to a neutral current-carrying conductor. Due to the phase difference, the voltage on any conductor reaches its peak at one third of a cycle after one of the other conductors, and one third of a cycle before the remaining conductor. Each phase input in conjunction with the common neutral conductor may be used to power a separate load.
In order to achieve good power quality in three-phase power system, balancing output loading is desirable. Load balancing makes input phase currents balance automatically, and there will be no current flowing into the neutral wiring. This prevents unnecessary power consumption in the input power system, and also can avoid losses voltage drop in phase voltage (line-to-neutral) to one or more of the loads. Therefore, the load for each of the phases should be as similar as possible. For example, in
However, in this case of systems similar to the system 10 in
In the existing technology, output current sharing can be used to provide load balancing. Output current sharing is implemented easily via a drop method or an active current-sharing method.
If the power supply units 70, 72, and 74 are installed on the same power shelf 76, this arrangement allows current-sharing signals (e.g., by a shared bus) to be connected together. This configuration allows input phase-current to be balanced automatically. In most application, load sharing control adopts an automatic master-slave current sharing control via current sharing controllers on each power supply. Thus, the supply that delivers the highest current (as sensed by an internal resistor) acts as the master and drives a common reference (e.g., a shared bus) to a voltage proportional to its output current. The feedback voltage of the other parallel power supplies (slaves) is then trimmed by an “adjustment” network so that they can support their amount of load current. The slave power units supply work as current-controlled current sources. Although adding a current-sharing circuit is feasible to provide load balancing, it makes power systems more complicated, resulting in increased costs.
Therefore, there is a need for a simplified system to provide balanced current sharing without the need for current sharing circuitry. There is a further need for a system that allows power supply units to provide current sharing without requiring the power supply units be installed on a common power shelf.
One disclosed example is a system for current balancing from a three-phase AC power source. The system includes power supply units, each having inputs coupled to one output of the three phase power source, and a neutral conductor. Multiple loads are each coupled to a DC output of one of the power supply units. Each of the loads includes a component having adjustable power consumption. A controller is coupled to each of the power supply units and each of the loads. The controller is operable to compare the power consumption of each of the loads to an average value. The controller adjusts the power consumption of at least one of the loads to balance the power consumption between the loads.
Another example is a method for insuring current balancing from a three-phase AC power source. An input of each of a plurality of power supply units is coupled to one output of a three-phase AC power source and a neutral conductor. A DC output of each of the plurality of power supply units is coupled to a plurality of loads. Power consumption of each of the plurality of loads is determined. Each of the loads includes a component having adjustable power consumption. The power consumption of each of the loads is compared to a predetermined value via a controller, coupled to each of the plurality of power supply units and each of the plurality of loads. The power consumption of at least one of the components of one the loads is adjusted to balance the power consumption between the loads.
The above summary is not intended to represent each embodiment or every aspect of the present disclosure. Rather, the foregoing summary merely provides an example of some of the novel aspects and features set forth herein. The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of representative embodiments and modes for carrying out the present invention, when taken in connection with the accompanying drawings and the appended claims.
The disclosure will be better understood from the following description of exemplary embodiments together with reference to the accompanying drawings, in which:
The present disclosure is susceptible to various modifications and alternative forms. Some representative embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
The present inventions can be embodied in many different forms. Representative embodiments are shown in the drawings, and will herein be described in detail. The present disclosure is an example or illustration of the principles of the present disclosure, and is not intended to limit the broad aspects of the disclosure to the embodiments illustrated. To that extent, elements and limitations that are disclosed, for example, in the Abstract, Summary, and Detailed Description sections, but not explicitly set forth in the claims, should not be incorporated into the claims, singly or collectively, by implication, inference, or otherwise. For purposes of the present detailed description, unless specifically disclaimed, the singular includes the plural and vice versa; and the word “including” means “including without limitation.” Moreover, words of approximation, such as “about,” “almost,” “substantially,” “approximately,” and the like, can be used herein to mean “at,” “near,” or “nearly at,” or “within 3-5% of,” or “within acceptable manufacturing tolerances,” or any logical combination thereof, for example.
The below described method and system senses current from a three phase AC source to different loads. If an imbalance of current is detected, a controller, such as a rack management controller, adjusts the power consumption of one or more of the loads, to adjust the current to a predetermined level such as a desired average current from the three phases of the AC current source.
In this example, each of the power supply units 112, 114, and 116 supply DC power to a corresponding power consuming load such as server loads 130, 132, and 134. The server loads 130, 132, and 134 all have corresponding cooling mechanisms such as a fan wall or corresponding fans 140, 142, and 144, for cooling electronic components in the respective server. The rack management controller 126 may control the speed of the fans 140, 142, and 144. A communication bus 146 allows internal controllers on the server loads 130, 132, and 134, to communicate operational data of the server to the rack management controller 126. In this example, the communication bus 146 is an IPMI communication bus. The rack management controller 126 may be connected to a power management bus 148 to receive data from the power meters 120, 122, and 124.
Depending on the components in the server loads 130, 132, and 134, as well as the operation of the system 100, the server loads 130, 132, and 134 may consume different power levels. As such there may be load imbalance between the loads. For example, if the server loads 130, 132, and 134 have components that require different levels of power, there may be a load imbalance. Further, if one of the server loads is operating at a higher level, it may require more power. The corresponding fan may also consume more power to cool the active server load.
In this example, the baseboard management controller 180 is connected via the communication bus 146 (from
To decrease the effects of unbalanced loads, several actions can be taken by the system 100. The first and most basic solution is to rearrange or redistribute the loads in such a way that the system 100 becomes more balanced.
In the components of the system 100 shown in
In this example, the rack management controller 126 may adjust the loading on each of the power supply units 112, 114, and 116, by increasing or decreasing the fan speed of one or more of the respective fans 140, 142, and 144 until the supply current for the respective power supply units 112, 114, and 116 matches the required value. The speed of the fans 140, 142, and 144, is proportional to the current required by the respective server loads 130, 132, and 134. In this manner, input current will be balanced in the three-phase system 100 once loading is balanced between the servers 130, 132, and 134.
The PSU 112 shown in
In this example, the rack management controller 126 adjusts the current requirements by adjusting fan speed such that the three power supply units 112, 114, and 116 share the load so that input current sharing between the loads meets the requirements in the plus or minus 10% reasonable tolerance. When new loads are added, the system may have a momentary unbalance, but this situation does not serious system operation. Input current of a three-phase source system would achieve balance. The fan speed of each server and CPU switching frequency of each server may be increased or decreased via BMC or RMC commands to achieve a current balance of the system output load. The control method for a PCU is similar to fan speed control. When system loading imbalance occurs, the CPU is operated at a throttling mode, which runs the CPU at a lower speed, keeps it cooler, and uses less power. This occurs because power use in a CPU is linear with clock frequency.
For example, if the power consumption of the server load 130 is sensed as 65 W, and the power consumption of the server loads 132 and 134 is sensed as 50 W, the rack management controller 126 will determine an imbalance situation. In this example, the rack management controller 126 may reduce the fan speed of the fan 140 so the power consumption of the server load is reduced to 55W, which is within 10% of the desired average power consumption level of 50W. In another example, if the power consumption of the server loads 130 and 132 is sensed as 60 W, and the power consumption of the server load 134 is sensed as 50 W, the rack management controller 126 will determine an imbalance situation. In this example, the rack management controller 126 may reduce the fan speed of the fans 140 and 142 so the power consumption of the server loads 130 and 132 is reduced to 55W, which is within 10% of the desired average power consumption level of 50W.
A flow diagram in
As shown in
As used in this application, the terms “component,” “module,” “system,” or the like, generally refer to a computer-related entity, either hardware (e.g., a circuit), a combination of hardware and software, software, or an entity related to an operational machine with one or more specific functionalities. For example, a component may be, but is not limited to being, a process running on a processor (e.g., digital signal processor), a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a controller, as well as the controller, can be a component. One or more components may reside within a process and/or thread of execution, and a component may be localized on one computer and/or distributed between two or more computers. Further, a “device” can come in the form of specially designed hardware; generalized hardware made specialized by the execution of software thereon that enables the hardware to perform specific function; software stored on a computer-readable medium; or a combination thereof.
The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof, are used in either the detailed description and/or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.”
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. Furthermore, terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur or be known to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.
