Method and system for providing power from a utility power source or a photovoltaic (PV) system to information technology

According to one embodiment, an Information Technology (IT) power system for a data center. The system includes a utility power source, an IT cluster that includes a several pieces of IT equipment. The cluster is coupled to the source and is configured to draw power from the source and provide the drawn power to the pieces of IT equipment. The system also includes a photovoltaic (PV) system that includes a PV panel that is arranged to convert solar radiation into direct current (DC) power. It also may include a voltage sensor and a controller that are configured to decouple the cluster from the source and to couple the cluster to the PV system such that the cluster draws the DC power directly from the PV panel when the output voltage of the PV panel sensed by the voltage sensor exceeds a threshold value.

FIELD

Embodiments of the present disclosure relate generally to an information technology (IT) power system with a photovoltaic (PV) system for a data center.

BACKGROUND

Large clusters of computer servers can be kept in dedicated facilities (e.g., data centers), often in a rack enclosure. These dedicated facilities require a considerable amount of power, which is drawn from a utility (e.g., alternating current (AC) mains). Along with needing power to operate the clusters of computer servers, the facilities also draw power to maintain a well regulated environment (e.g., through the use of a computer room air conditioning (CRAC) unit). Drawing such a large amount of power from the AC mains increases the overall cost of operating a facility and increases the facility's carbon footprint.

To decrease dependency on the AC mains and reduce a carbon footprint, some facilities are turning to renewable power systems, such as a photovoltaic (PV) system.FIG.1illustrates an example of a PV system100. This system includes a PV panel101, an inverter/charger102, a load103, and one or more batteries104. During operation, the PV panel101converts solar radiation into electrical direct current (DC) power. The inverter/charger102(e.g., which may be separate components) converts the DC power into AC power that is used to power the load103. In the case of dedicated facilities, the load may be any electrical component, such as a computer server. Along with (or in lieu of) powering the load, the inverter/charger may charge the batteries104to store the energy produced by the solar panel to be used later to power the load. For instance, at night the inverter may draw energy from the batteries104to power the facility's components.

Implementing a PV system, such as system100illustrated inFIG.1for a data center has many drawbacks. In particular, the PV system100can be expensive and significantly increase the complexity of the implementation of the facility. For example, such a PV system that includes several batteries will increase complexity due to the extra components required for maintaining (e.g., charging/discharging) the batteries. In addition, the incorporation of batteries will increase the overall cost of operating and implementing a PV system (e.g., due to having a considerable amount of batteries in order to store enough energy to run the data center).

DETAILED DESCRIPTION

Several embodiments of the disclosure with reference to the appended drawings are now explained. Whenever the shapes, relative positions and other aspects of the parts described in a given aspect are not explicitly defined, the scope of the disclosure here is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some aspects may be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description. Furthermore, unless the meaning is clearly to the contrary, all ranges set forth herein are deemed to be inclusive of each range's endpoints.

As described herein, a switch is configured to be “open” (or off) when there is no continuity between one terminal and another terminal (e.g., an input contact and an output contact) of the switch, which does not allow electric current to flow through the switch. In contrast, a switch is configured to be “closed” (or on) when there is continuity between the two terminals of the switch, which allows the electric current to flow through the switch. In one embodiment, a switch may be a bidirectional switch, which allows a two-way bidirectional flow of current when on, based on the polarity of the two terminals of the switch. In one embodiment, a switch as described herein may have one or more terminals.

The present disclose solves the problem of reducing cost (e.g., component cost, operating cost, service/maintenance cost, etc.) and complexity of implementing a photovoltaic (PV) system in a data center by eliminating (or removing) the need for batteries. The solution proposed in the current disclosure provides an information technology (IT) power system for a data center that includes a PV system with a PV panel from which solar power is (e.g., directly) drawn (e.g., not drawn from a battery) to power IT equipment within an IT cluster. Specifically, the IT cluster is coupled to a utility power source (e.g., alternating current (AC) mains) and is configured to provide utility power drawn from the source to the IT equipment. A controller is configured to decouple the IT cluster from the utility power source and to couple the IT cluster to the PV system such that the IT cluster draws power from the PV panel when an output voltage of the PV panel exceeds a threshold voltage. For instance, the threshold voltage may be based on at least IT cluster characteristics (e.g., current power requirements for operating the IT equipment of the IT cluster, etc.). Otherwise, the IT cluster may remain coupled to the utility power source only. As another feature, the DC power produced by the PV panels may be provided to the IT cluster in excess of the utility power. In other words, the controller may be configured to couple both power sources, the utility power source and the PV panel, to the IT cluster to provide power. As a result, along with lowering the Total Cost of Ownership (TCO) by reducing the number of components necessary to operate a PV system, the present disclosure efficiently manages and regulates power requirements for the IT cluster under different operating conditions of its IT equipment.

According to one embodiment, an Information Technology (IT) power system for a data center, the IT power system including a utility power source; an IT cluster that includes a several pieces of IT equipment, at least one of the pieces of IT equipment including one or more servers to provide data processing services, wherein the IT cluster is coupled to the utility power source and is configured to draw utility power from the utility power source and provide the drawn utility power to the pieces of IT equipment; a photovoltaic (PV) system that includes a PV panel that is arranged to convert solar radiation into direct current (DC) power; and a controller that is configured to decouple the IT cluster from the utility power source and to couple the IT cluster to the PV system such that the IT cluster draws the DC power from the PV panel when an output voltage of the PV panel exceeds a threshold voltage.

In one embodiment, the PV system further includes a voltage sensor that is coupled to the PV panel and a switch that is coupled between the voltage sensor and the IT cluster, wherein the voltage sensor is arranged to sense the output voltage of the PV panel as an open-circuit voltage of the PV panel while the PV system is not coupled with any load when the switch is open. In some embodiments, the switch is a first switch, wherein the PV system further includes a second switch that is coupled between the first switch and the IT cluster; and a DC-to-DC converter that is coupled between the first switch and the second switch and is configured to convert the output voltage of the PV panel into an output voltage of the DC-to-DC converter, wherein, in response to the output voltage of the PV panel exceeding the threshold voltage, the first switch and second switch are configured to close such that the output voltage of the DC-to-DC converter is input to the IT cluster.

In one embodiment, the PV system further includes a PV controller that is configured to receive the sensed output voltage of the PV panel from the voltage sensor, and in response to determining that the sensed output voltage of the PV panel exceeds the threshold voltage, close the first switch, and transmit a control signal to the controller indicating that the output voltage of the PV panel exceeds the threshold voltage, wherein the controller closes second switch in response to receiving the control signal from the PV controller. In another embodiment, the DC-to-DC converter is a first DC-to-DC converter, wherein the PV system further includes a second DC-to-DC converter that is coupled between the first switch and the first DC-to-DC converter, wherein the second DC-to-DC converter is configured to convert the output voltage of the PV panel into an output voltage of the second DC-to-DC converter that is input to the first DC-to-DC converter and with which the first DC-to-DC converter is configured to convert into the output voltage of the first DC-to-DC converter. This may improve the system design efficiency and component selection flexibilities under some circumstances. In some embodiments, the PV panel is a first PV panel and the voltage sensor is a first voltage sensor, wherein the PV system further includes a second PV panel; a second voltage sensor that is coupled to the second PV panel; a third switch that is coupled to the second voltage sensor, wherein the second voltage sensor is configured to sense an output voltage of the second PV panel as an open-circuit voltage while the PV panel is not coupled with any load when the third switch is open; a third DC-to-DC converter that is coupled to the third switch and is configured to convert the output voltage of the second PV panel into an output voltage of the third DC-to-DC converter; and a DC bus that couples the second and third DC-to-DC converters in parallel to the first DC-to-DC converter, wherein, in response to both open-circuit voltages of the first and second PV panels exceeding the threshold voltage, the first switch, the second switch, and the third switch are configured to close. In one embodiment, the PV system is a first PV system, wherein the IT power system further includes a second PV system that has a same arrangement of components as the first PV system; and a DC bus that couples the first PV system and the second PV system in parallel to the IT cluster which is configured to draw DC power from either or both of the PV systems.

In one embodiment, the PV system does not include a battery from which the IT cluster may draw stored DC power converted by the PV panel. In another embodiment, the IT power system further includes a DC bus to which the PV system and IT cluster are coupled; a first switch that is coupled between the utility power source and the IT cluster; a second switch that is coupled between the IT cluster and the DC bus; and a third switch that is coupled between the PV system and the DC bus, wherein the first switch is closed and the second and third switches are open while the IT cluster draws utility power from the utility power source, wherein the controller decouples the IT cluster from the utility power source and couples the IT cluster to the PV system by opening the first switch and closing the second and third switches.

According to another embodiment, a data center includes a data center IT room and an IT power system, as previously described.

According to another embodiment, a method performed by a programmed processor of an IT power system for a data center, the IT power system including a PV system that has a PV panel that is arranged to convert solar radiation into DC power. The method includes providing utility power from a utility power source to an IT cluster that includes a plurality of pieces of IT equipment; determining that an output voltage of the PV panel exceeds a threshold voltage; and in response to determining that the output voltage exceeds the threshold voltage, providing the DC power from the PV panel to the IT cluster. In one embodiment, the method determines the threshold voltage based on PV system characteristics and IT cluster characteristics. In some embodiments, the PV system has a voltage sensor that is coupled to the PV panel and a switch that is coupled between the voltage sensor and the IT cluster, wherein the method further includes receiving, from the voltage sensor, a measurement of the output voltage as an open-circuit voltage of the PV panel while the PV system is not coupled with any load when the switch is open. In one embodiment, the IT power system has 1) a second switch that is coupled between the utility power source and the IT cluster and 2) a third switch that is coupled between the PV system and the IT cluster, wherein providing the DC power includes closing the first switch and the third switch while the second switch is open. In another embodiment, the PV system does not include a battery from which the IT cluster may draw stored DC power converted by the PV panel.

FIG.2is a block diagram illustrating an example of an IT power system1according to one embodiment. Specifically, this figure shows the IT power system1that may be implemented in a data center in order to power (e.g., one or more pieces of IT equipment of) one or more IT clusters using solar power produced by one or more PV systems that do not include batteries from which the solar power may be drawn. More about the PV systems is described herein. The IT power system includes one or more IT power modules2a-2n, a DC bus4, and a central controller3. The DC bus4(or DC busbar) may be a power rail or power bus that is coupled to one or more components within each (or at least some) of the IT power modules2a-2nto distribute DC power from one or more DC power sources (e.g., PV systems10a-10n, as described herein) to the components (e.g., IT clusters). In one embodiment, the DC bus may be any electronic component that may distribute power, such as a metallic strip, bar, or wire. In some embodiments, the DC bus may include connection ports that allow components to be connected to or disconnected from the bus.

The central controller3may be a special-purpose processor such as an application-specific integrated circuit (ASIC), a general purpose microprocessor, a field-programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures (e.g., filters, arithmetic logic units, and dedicated state machines). In one embodiment, the controller may be a circuit with a combination of analog elements (e.g., resistors, capacitors, inductors, etc.) and/or digital elements (e.g., logic-based elements, such as transistors, etc.). The controller may also include memory. In one embodiment, the central controller3may be configured to perform one or more operations described herein for providing solar power from one or more PV systems to one or more IT clusters. For example, the controller may be configured to execute a machine learning (ML) algorithm that has operations to determine how and when to provide solar power, utility power, stored energy, or a combination thereof to the IT clusters. More about the central controller is described herein.

The IT power module2aincludes one or more power sources including a utility power source5a, an energy storage device7a, and a PV system10a. In one embodiment, the power module is arranged to provide power from one or more of the sources to one or more loads at any given time. The module2aalso includes other electronic components such as a AC-to-DC converter6a, an IT cluster8a, and a system controller9a. In one embodiment, the power module may include more or less elements (or components), such as having one or more IT clusters. As another example, the power module may not include an energy storage device7a.

As illustrated, the IT power system1may include one or more power modules, as illustrated by having modules2athrough2n. In one embodiment, each of the modules may be configured to power a respective IT cluster and/or one or more IT clusters of other IT power modules via the DC bus4to which each of the modules is coupled. More about the power modules being coupled to the DC bus4is described herein. In one embodiment, each of the IT power modules may be configured similarly to one another. For example, as shown, the power module2nincludes the same (e.g., number of) components in the same configuration as module2a. In another embodiment, however, at least some of the power modules (e.g., module2n) may include different components (and/or different number of components), which may be in a different (or same) configuration as shown in module2a.

The utility power source5amay be any type of power source that is designed to provide AC power, such as the AC mains or a generator. In one embodiment, the utility power source may include a DC power source (e.g., a battery, a DC bus, etc.) coupled to a power inverter that is designed to convert DC power back into AC power. In one embodiment, the utility power source is a main power source from which one or more components within the IT power module (e.g., the IT cluster) draws power. The AC-to-DC converter (or inverter)6ais (e.g., electrically) coupled to the utility power source5a, and is arranged to receive AC power from the source. The AC-to-DC converter is configured to convert AC power to DC power by converting AC voltage supplied by the utility power source into a DC voltage. In one embodiment, the AC-to-DC converter may be any type of converter, such as a buck, a boost, or a flyback converter. In some embodiments, the utility power source path which is illustrated as only having the source5a, the converter6a, and the switch S1a, may include one or more additional electronic components that enable the facility power system to provide utility power to the IT cluster.

The IT cluster8amay include one or more pieces of IT equipment (e.g., one or more servers that provide data processing services). In one embodiment, the IT cluster may include (or be a part of) an electronic rack that includes the IT equipment, such as rack500illustrated inFIG.8. In another embodiment, the IT cluster may include IT equipment that is a part of one or more electronic racks. As shown, the IT cluster is coupled to the utility power source via the AC-to-DC converter. The IT cluster is configured to draw utility power from the utility power source that is converted into DC power by the converter6a, and is configured to provide the drawn utility power to the cluster's one or more pieces of IT equipment. The IT cluster is also coupled to the DC bus4, and is configured to draw power from the DC bus, as described herein.

In one embodiment, although the components in this figure are illustrated as separate blocks, at least some may be integrated with one another. For example, the AC-to-DC converter6aand/or the energy storage device7amay be located in the IT cluster. In this case, both components may be a part of (or integrated within) one or more racks (such as rack500) that are a part of the IT cluster. As another example, S5amay be a part of the PV system10a, as illustrated inFIGS.3aand3b.

The PV system10ais configured to produce DC power that is converted from solar radiation, and provide the power to the DC bus4. More about the PV system is described herein. The energy storage device7ais coupled to the AC-to-DC converter6a, and is coupled to the DC bus4. In one embodiment, the energy storage device may be any type of device that is configured to store and discharge energy, such as an uninterruptible power supply (UPS), one or more batteries, etc. Thus, the storage device may include one or more rechargeable energy storage devices.

As illustrated, the IT power module2aincludes several switches S1a-S5a. In one embodiment, the switches (or relays) may be any type of (e.g., power) switches that allows (e.g., DC) current to flow (e.g., between two terminals of the switch) when closed and prevents current from flowing when open. As shown, S1ais coupled (e.g., disposed) between the AC-to-DC converter6aand the IT cluster8a; S2ais coupled between the AC-to-DC converter and the energy storage device7a; S3ais coupled between the energy storage device and the DC bus4; S4ais coupled between the IT cluster8aand the DC bus4; and S5ais coupled between the PV system10aand the DC bus4. In one embodiment, the IT power module2amay include more or less switches as those described herein. In another embodiment, each of the switches is “coupled (or disposed) between” two electronic components such that one terminal of the switch is coupled to one of the electronic components and another terminal of the switch is coupled to the other electronic component, such that when opened current may flow between the components and when closed current is prevented from flowing between the components.

In one embodiment, each of the switches S1a-S5ais configured to open or close according to one or more control signals received from one or more controllers (or any electronic devices) that are communicatively coupled (e.g., via a wired connection using any communication protocol, such as System Management Bus (SMBus)) with the switch. For instance, the IT power module2aincludes a system controller9athat is (at least) communicatively coupled with S1aand S2a, while the central controller3is (at least) communicatively coupled with S3a, S4a, and S5a. In one embodiment, either of the controllers may be communicatively coupled with more or less switches. For instance, the central controller may be communicatively coupled with all five switches of the IT power module2a. In one embodiment, the IT power module2amay not include a system controller, which as a result the central controller may communicate with each of the switches within the module. In some embodiments, one or more of the controllers may be communicatively coupled via a wireless connection with one or more of the switches in order to transmit the control signals.

In some embodiments, the IT power system1may operate in one of several configurations in order to provide power to one or more IT clusters. Specifically, the central controller is configured to couple the IT cluster8aof the IT power module2ato one or more power sources. In a first configuration, the central controller3is configured to provide utility power from utility power source5ato IT cluster8aby connecting the utility power source5ato the IT cluster and disconnecting other power sources, such as the PV system10a. For instance, to provide utility power, the central controller is configured to open S4a(and open S5aand/or open S3a) and instruct (e.g., via a control signal transmitted to) the system controller9ato close S1a. In a second configuration, the control controller3is configured to provide power from PV system10ato the IT cluster by connecting the PV system to the IT cluster and disconnecting other power sources, such as the utility power source5a. In this configuration, the central controller is configured to close S4aand S5a; and is configured to instruct the system controller9ato open S1a. In a third configuration, the central controller3may be configured to provide power from the energy storage device7ato the IT cluster. For instance, the central controller may be configured to open S5a, close S3aand S4a; and may be configured to instruct the system controller9ato open S1aand/or S2a. In one scenario, S2amay close for charging the storage device7a. In some embodiments, other configurations are capable in which the central controller (and/or the system controller) powers the IT cluster from one or more of the power sources described herein.

In one embodiment, in any of these configurations, the energy storage device7amay be coupled or decoupled from the DC bus4and/or the AC-to-DC converter6a. In particular, while in at least some of the configurations the system controller9amay open S2aand the central controller may open S3ain order to electronically isolate the storage device from the AC-to-DC converter6a, and from the DC bus4. In another embodiment, the storage device may be coupled to one or more of the electrical components in order to discharge energy and power one or more components. For example, to power the IT cluster8a, S2a(and/or S5a) may be opened, while S3a(and S4a) are closed. To charge the storage device7a, utility power may be used by closing S2aand opening S3a. In one embodiment, power drawn from the PV system10amay be used to charge the storage device by opening S2aand closing S3a(and S5a).

Some of the configurations described herein relate to providing power to one or more IT clusters from one power source, such as from the utility power source. In another embodiment, however, power may be provided to one or more IT clusters from one or more power sources. For example, along with providing utility power from the utility power source (e.g., while S1ais closed), the IT power system1may also provide the IT cluster power from the DC bus4(and from the PV system10a). In this case, S1aand S4a(and S5a) may be closed to provide power from several sources. This allows the IT cluster to draw some power from the utility power source, while supplementing power that would otherwise be drawn from the utility power source from the (e.g., PV system10athat is providing power to the) DC bus4.

In another embodiment, the central controller3may be configured to perform operations to determine whether one or more power sources of one or more IT power modules are to be coupled to one or more IT clusters in order to provide power. Specifically, the central controller3may determine whether an IT cluster (e.g., IT cluster8a) is to draw utility power or power from one or more PV systems (such as its respective PV system10a) based on one or more criteria. For instance, the central controller3may determine one or more IT cluster characteristics, such as an operating power level for the IT cluster8a(e.g., a requirement for powering the IT cluster's one or more pieces of IT equipment). In one embodiment, the central controller may communicate with the system controller9aand/or the IT cluster8ato determine the cluster's characteristics. In some embodiments, the central controller may determine one or more PV system characteristics of the PV system10a. For example, the central controller may determine an output voltage (e.g., an open-circuit voltage) across one or more PV panels of the PV system, and from the output voltage determine whether the PV system may provide sufficient power to operate the IT cluster in lieu of (and/or in addition to) the utility power source. More about the operations performed by the central controller3is described herein.

FIGS.3aand3bshow an example of a PV system that does not include a battery according to one embodiment. Specifically, each of these figures show PV system10a(e.g., of IT power module2a) that includes a PV panel22, a voltage sensor23, a DC bus25, and two DC-to-DC converters24and26. In one embodiment, the PV system illustrated in these figures may be the same in each of the IT power modules2a-2nof the IT power system1. In another embodiment, however, at least some of the PV systems may be different. For instance, a PV system may include more or less components, such as having two or more PV panels. In another embodiment, the PV system may only include one DC-to-DC converter. The PV system also includes switches, S6aand S5a. As shown, each of these components are arranged (coupled) in series. Specifically, the voltage sensor is coupled to the PV panel, and switch S6ais coupled after the voltage sensor (e.g., between the sensor and the IT cluster). S6ais then coupled to the DC-to-DC converter24, which is coupled to the DC-to-DC converter26via the DC bus25. In one embodiment, the DC-to-DC converter24may be coupled directly to the DC-to-DC converter26, in which case the PV system may not include DC bus25. The DC-to-DC converter26is coupled to the DC bus4via the switch S5a. In one embodiment, the PV system includes the two switches in order to isolate the PV panel22and the converters24and26to avoid high voltage damage. In another embodiment, the PV system may include additional switches, such as having a switch coupled between the PV panel and the voltage sensor. Such a switch may be opened when the PV panel needs to be replaced or serviced in order to ensure that the remainder of the components are isolated.

The PV panel22is arranged to convert solar radiation into DC power. The voltage sensor23is arranged to sense an output (e.g., DC) voltage of the PV panel (Vout1). In one embodiment, the voltage sensor is arranged to sense an open-circuit voltage of the PV panel while the (e.g., PV panel of the) PV system is not coupled with any load (e.g., any IT cluster) when switch S6ais open. In some embodiments, the voltage sensor may be any type of sensor that is designed to sense an output voltage. The PV controller21is communicatively coupled to the switch S6a, the voltage sensor and the central controller3. The PV controller is configured to receive (e.g., measure) sensed output voltage of the PV panel from the voltage sensor, and is configured to open/close S6abased on the output voltage, as described herein. More about the PV controller is described herein. Both DC-to-DC converters24and26are configured to convert an input (e.g., a respective input) DC voltage into an output (e.g., a respective) DC voltage. In one embodiment, the converters may each be any type of DC-to-DC converter, such as a buck converter, a boost converter, or a buck-boost converter. More about the DC-to-DC converters is described herein. More about the operations performed by the converters is described herein.

Returning toFIG.3a, this figure illustrates that the (e.g., PV panel22of the) PV system10ais isolated from the DC bus4and is not providing DC power the bus. Specifically, in this figure both S6aand S5aare in an open configuration. In one embodiment, this figure represents an arrangement of the PV system10ain which the IT power system1is providing power to the IT cluster8afrom another source. For example, the IT power system1may be operating in the first configuration described herein in which the IT cluster8ais drawing utility power from the utility power source5a. In particular, the switches (or at least one of the switches) of the PV system may be opened based on Vout1being above a threshold voltage. More about the threshold voltage is described herein.

FIG.3bshows an example of the PV system providing DC power to the DC bus according to one embodiment. Specifically, S6ahas been closed by the PV controller21and S5ahas been closed by the central controller3. In one embodiment, this figure represents the arrangement of the PV system10a, while the IT power system is operating in (at least) the second configuration described herein in which the IT cluster8ais drawing power from the PV system. In another embodiment, the IT system may be drawing power from both power sources, as described herein. Thus, since the PV system does not include a battery from which stored DC power converted by the PV panel may be drawn, the IT cluster is drawing DC power (e.g., directly) from the PV panel.

As described herein, the PV system may be configured to provide power to the IT cluster8ain response to Vout1of the PV panel exceeding (or meeting) a threshold voltage. As shown, the DC-to-DC converter24converts Vout1to an output voltage Vout2, which may be lower or greater than Vout1. In addition, the second DC-to-DC converter26is converts Vout2to Vout3, which may be an operating voltage of the IT cluster. In one embodiment, the PV system includes two converters in order to normalize Vout1before it is converted into a desired DC voltage for the IT cluster (or more specifically a desired DC voltage of the DC bus4). In one embodiment, Vout2may be different than Vout3, which may allow one or more additional electronic components (not shown) to draw power from DC bus25, where these components may operate at a different DC voltage than the Vout3, which is across the DC bus4(and input to the IT cluster, as described herein).

FIG.4is a signal diagram of a process50performed by the central controller3and the PV controller21for providing DC power from the PV panel22to the IT cluster8a(via the DC bus4), according to one embodiment. For instance, this figure illustrates the operations performed by the controllers while the PV system10ais not providing DC power, as illustrated inFIG.3a. In one embodiment, these operations may be performed by controllers of one or more IT power modules2a-2nand/or by the central controller. The process50begins by the central controller3providing utility power from the utility power source5ato the IT cluster8athat includes one or more pieces of IT equipment (at block51). For instance, the central controller3(and the system controller9a) may configure the IT power module in the first configuration described herein, in which S1ais closed and at least S4ais open. The central controller3transmits a first control signal to the PV controller21, which instructs the PV controller to measure the output voltage, Vout1, across PV panel22. In one embodiment, the first control signal may activate or “wake up” the PV controller, which may be operating in a standby mode in order to conserve power.

The PV controller21measures the output voltage, Vout1, across the PV panel (at block52). Specifically, the PV controller receives the output voltage as an open-circuit voltage that is measured by the voltage sensor23, while Sais open. The PV controller21transmits the measured output voltage to the central controller.

The central controller3determines a threshold voltage (at block53). In one embodiment, the threshold voltage may be a predefined voltage value based on engineering calculation and characterizations. In another embodiment, the central controller determines the threshold voltage based on characteristics of the IT power system1, such as PV system characteristics and/or IT cluster characteristics. As described herein, the central controller determines whether one or more IT clusters are to draw utility power, stored energy, power from one or more PV systems, or a combination thereof based on one or more criteria, which may include PV system and/or IT cluster characteristics. In one embodiment, the PV system characteristics may include a maximum power point (MPP), which is the maximum amount of power the panel may generate, a maximum current that may be provided by the panel, a fill factor that is a relationship between a maximum amount of DC power that may be provided by the panel under normal operating conditions, and an efficiency of the panel. In some embodiments, the threshold voltage may be based on open-circuit voltage (of the PV panel) and closed-circuit voltage relationship that is characterized based on the PV system and the IT load characteristics. For example, the open-circuit voltage of the PV panel may reflect the PV system characteristics and is used to calculate the (e.g., potential) power generation from the PV system. Thus, different PV systems with different components, such as different PV panels may have different open-circuit voltages.

In another embodiment, the PV system characteristics may also include characteristics of other components within the system, such as efficiency of the DC-to-DC converters24and26, and internal resistances of the switches S6aand S5a. In one embodiment, the PV system characteristics may also indicate whether additional electronic components are to draw power that is to be produced by the PV panel22, such as components that may be electrically coupled to the DC bus25of the PV system. In some embodiments, the IT cluster characteristics may include the operating power level of the IT cluster, as described herein. As another example, the IT characteristics may also include other characteristics that may impact the overall power requirement of the IT cluster, such as power required for cooling the pieces of IT equipment. To determine the threshold voltage, the central controller may apply one or more characteristics as described herein as input into a predefined model that generates from the input the threshold voltage as output. As another example, the central controller may perform a table lookup using one or more of the characteristics into a lookup table that associates the characteristics with predefined threshold voltages.

The central controller3determines whether the output voltage, Vout1, is greater than the threshold voltage (at decision block54). In one embodiment, Vout1is an open-circuit voltage while S6ais open, as described herein. If not, the central controller continues to provide utility power to the IT cluster (at block55). If, however, Vout1is greater than the threshold voltage, the central controller3disconnects the IT cluster from the utility power source and connects the IT cluster to the PV system (at block56). Specifically, the central controller transmits a signal to the system controller9ato open S1a(and S2a), and the central controller closes S4aand S5a(and may open S3a). The central controller3transmits a second control signal to the PV controller21instructing the controller to connect the PV system to the IT cluster. In response, the PV controller connects the PV system10ato the IT cluster8ato provide DC power produced by the PV panel to the cluster (at block57). As described herein, the PV controller may close S6a, thereby allowing solar energy to (e.g., directly) flow from the PV panel into the IT cluster8a(e.g., through the DC bus4).

In some embodiments, the controllers may adjust the configuration of the switches in any particular order. For instance, S5amay be closed by the central controller before S6ais closed by the PV controller. In this case, S1amay be opened before S5aand S6aare closed. Thus, the closing of S5aand S6amay be performed while S1ais open. In another embodiment, S1amay be opened before S4ais closed to electronically couple the IT cluster to the PV system via the DC bus4. In another embodiment, the order in which the switches are closed may be performed differently, such as closing S6a, S5a, and then S4a.

Some embodiments may perform variations to the processes described herein. For example, the specific operations of at least some of the processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations and different specific operations may be performed in different embodiments. For example, at the beginning of the process50the IT cluster is being provided utility power. In another embodiment, the process may begin while the IT cluster is being provided DC power being produced by the PV panel (e.g., while the IT power system is in the second configuration, as described herein). In this case, in response to determining that the output voltage is not greater than the threshold voltage, which may be due to less favorable weather conditions (e.g., cloudy skies, or nighttime is approaching), the process may disconnect the PV panel from the IT cluster and connect the IT cluster to the utility power source. Specifically, once the PV system is connected to a load (e.g., the DC bus4), the controller (e.g., the central controller and/or the PV controller) may be configured to detect the current power output based on a closed circuit voltage (e.g., while S6ais closed). As example, when the close circuit voltage drops, it means the power generated from the PV panel may not able to provide usable quality of power given the input DC requirement for converters24or26. Thus, in determining that the output voltage, which is the closed-circuit voltage (due to the PV system providing power), the controller disconnects the IT cluster from the PV system by opening one or more switches of the PV system, such as S5aand/or S6ato cut the PV power. Otherwise, the PV system may continue providing DC power from the solar panel.

In another embodiment, at least some operations described in process50are optional operations, as illustrated by being dashed boxes. As a result, at least some of the operations may not be performed. For example, in response to determining that the output voltage is greater than the threshold voltage, the PV system may be connected such that the IT cluster is provided DC power produced by the PV system's PV panel and is provided utility DC power from the utility power source. As a result, the IT cluster may receive at least some power from both sources. This may allow the data center to draw less power from the utility, thereby enabling higher renewable power usage, reducing operating costs, and the center's carbon footprint.

As described herein, the central controller may perform one or more of the operations to power one or more IT clusters with one or more power sources. In this case, when multiple IT power modules,2a-2nare coupled to the DC bus4, the operations performed by the controllers may consider characteristics of those modules. For example, the determination of the threshold voltage may be based on whether one or more IT clusters are to be powered via the DC bus4and whether one or more PV systems may be used to provide (e.g., at least a portion) such power. Specifically, the determination may be based on IC cluster characteristics of the one or more IT clusters8a-8nand the PV system characteristics of one or more PV systems10a-10n. As a result, when the one or more PV systems output voltages' exceed the threshold voltage, the central controller may close their respective switches, and may connect the PV systems' respective IT clusters (and/or other IT clusters) to the DC bus4. In some embodiments, the central controller may connect a set of PV systems to the DC bus4, while only connecting a subset of IT clusters to the DC bus4. This may occur when the PV systems are unable to produce enough power to power all respective IT clusters, but may be able to power at least some.

As described herein, some operations may be performed by one or more controllers, such as the system controller9a, the PV controller21, and/or the central controller3. In one embodiment, however, some controllers may perform more or other operations than described herein. For instance, the PV controller may determine the threshold voltage. In another embodiment, all of the operations may be performed by one controller, such as the central controller3. In this case, the central controller may be communicatively coupled all of the components of the PV system, such as S5a, S6aand the voltage sensor23of the PV system10a, as illustrated inFIG.3a.

FIG.5is a flowchart of a process40for providing DC power from a PV panel of a PV system when an output voltage of the PV panel exceeds a threshold voltage according to one embodiment. In one embodiment, the process40may be performed by the central controller3. In another embodiment, at least some of the operations may be performed by other controllers, such as system controllers and/or PV controllers. In some embodiments, at least some of the operations in process40may be the same or similar to operations of process50. The process40begins by the central controller providing utility power from a utility power source to an IT cluster that includes several pieces of IT equipment (at block41). The central controller3determines that an output voltage of a PV panel (of a PV system) exceeds a threshold voltage (at block42). The central controller then, in response to determining that the output voltage exceeds the threshold voltage, provides DC power from the PV panel to the IT (at block43).

In one embodiment, the operations described in processes50and40ofFIGS.4and5, respectively, provide the IT power system1with the capability to switch from providing power from a utility power source to providing power from a renewable source, such as PV panels (e.g., and back again as needed). Thus, the controller may be configured to decouple the IT cluster from the utility power source and to couple the IT cluster to the PV system such that the IT cluster draws the DC power from the PV panel when an output voltage of the PV panel exceeds the threshold voltage. In another embodiment, the operations described herein may use the power produced by the PV panel to power one or more IT clusters in addition to power from one or more power sources, such as the utility power source, as described herein. In some embodiments, these operations may be performed in real-time, thereby allowing the system to dynamically switch between one or more sources (e.g., providing power from one or more sources) as needed.

FIG.6is a block diagram illustrating an example of a PV system with several PV panels that are arranged to be coupled in parallel according to one embodiment. This figure illustrates PV system10awith several additional electronic components that are coupled to the DC bus24. Specifically, the PV system10aincludes (at least) a PV panel22b, a voltage sensor23b, a DC-to-DC converter24b, and a switch S6b. Each of these components are in a same arrangement as PV panel22a, voltage sensor23a, switch S6a, and DC-to-DC converter24a. Thus, the voltage sensor23bis arranged to sense the output voltage Vout1′ of PV panel22b; and DC-to-DC converter24bis coupled to the DC bus25. Thus, both DC-to-DC converters24aand24bare coupled to the DC bus and are therefore in parallel to the DC-to-DC converter26. In one embodiment, the output voltage of each of the DC-to-DC converts24aand24bis the same. In some embodiments, the converters24aand24bmay be different and/or convert different input voltages to the output voltage. Specifically, this arrangement allows variances in the electronic components. For instance, both PV panels22aand22bmay be rated differently, while their respective converters are configured to normalize the output voltages of the panels to a similar (or same) DC voltage across the DC bus25.

In this configuration, the PV controller21is communicatively coupled to both switches S6aand S6band both voltage sensors. In response to the PV controller21determining that both output voltages, Vout1and Vout1′ exceed the threshold voltage, S6a, S6b, and S5aare closed. Having two PV panels22aand22bcoupled in parallel provides additional (e.g., double the) DC power to the DC bus4.

In one embodiment, the PV system10amay configure which (or how many) PV panels are to be connected in parallel based on IT power system requirements. For instance, with the addition of PV panels, the overall power capabilities of the PV system10aincreases. With the changes in the PV system characteristics, the determined threshold voltage may be adjusted to account for the addition of PV panels. In another embodiment, the PV system may be configured to connect some of the PV panels (e.g., only22a) in parallel, while leaving the others (e.g.,22b) decoupled. When more power is needed (e.g., IT clusters are requiring additional power), the PV system may connect more PV panels (e.g., both22aand22b) in parallel (e.g., by closing their corresponding switches, S6aand S6b).

FIG.7is a block diagram illustrating an example of several PV systems that are arranged to be coupled in parallel according to one embodiment. Specifically, this figure illustrates two PV systems10aand10bthat are configured to be coupled (and/or decoupled) to the DC bus4. In one embodiment, each of the PV systems is a part of a separate IT power module, such that10ais a part of module2aand10bis a part of module2b. This figure also illustrates that each of the PV systems is controlled by one PV controller21, rather than each of the PV systems having its own PV controller. In one embodiment, the PV controller21may independently control each of the PV systems based on whether the system's respective PV panel's output voltage (open-circuit voltage) exceeds the threshold voltage, as described herein. In another embodiment, each of the PV systems may include its own PV controller.

FIG.8is an example of an electronic rack according to one embodiment. Electronic rack500may include one or more server slots to contain one or more servers respectively. Each server includes one or more information technology (IT) components (e.g., processors, memory, storage devices, network interfaces). According to one embodiment, electronic rack500includes, but is not limited to, CDU501, rack management unit (RMU)502(optional), a power supply unit (PSU)550, and one or more pieces of IT equipment (or IT equipment)503A-503D, which may be any type of IT equipment, such as server blades. The IT equipment503can be inserted into an array of server slots respectively from frontend504or backend505of electronic rack500

Note that although there are only four pieces of IT equipment503A-503D shown here, more or fewer pieces of IT equipment may be maintained within electronic rack500. Also note that the particular positions of CDU501, RMU502, PSU550, and IT equipment503are shown for the purpose of illustration only; other arrangements or configurations of these components. may also be implemented. Note that electronic rack500can be either open to the environment or partially contained by a rack container, as long as the cooling fans can generate airflows from the frontend to the backend (or generate airflows from the backend to the frontend).

In one embodiment, the rack500may include one or more electronic components of the IT power system1. For instance, the rack500may include one or more IT clusters, such as IT cluster8a, the utility power source5a, the AC-to-DC converter6a, the energy storage device7a, the DC bus4, the system controller9a(e.g., as one of the pieces of IT equipment), and one or more of the switches.

In addition, a fan module can be associated with each of the pieces of IT equipment503, and the PSU module. In this embodiment, fan modules531A-531E, collectively referred to as fan modules531, and are associated with the pieces of IT equipment503A-503D and the PSU, respectively. Each of the fan modules531includes one or more cooling fans. Fan modules531may be mounted on the backends of IT equipment503to generate airflows flowing from frontend504, traveling through the rack500, and existing at backend505of electronic rack900. In another embodiment, one or more of the fan modules may be positioned on the frontend504of the rack500. Such frontend fans may be configured to push air into the mounted equipment.

In one embodiment, CDU501mainly includes heat exchanger511, liquid pump512, and a pump controller (not shown), and some other components such as a liquid reservoir, a power supply, monitoring sensors and so on. Heat exchanger511may be a liquid-to-liquid heat exchanger. Heat exchanger511includes a first loop with inlet and outlet ports having a first pair of liquid connectors coupled to external liquid supply/return lines532-533to form a primary loop. The connectors coupled to the external liquid supply/return lines532-533may be disposed or mounted on backend505of electronic rack500. The liquid supply/return lines532-533are coupled to a set of room manifolds, which are coupled to an external heat removal system, or external cooling loop. In addition, heat exchanger511further includes a second loop with two ports having a second pair of liquid connectors coupled to liquid manifold525to form a secondary loop, which may include a supply manifold to supply cooling liquid to the pieces of IT equipment503and a return manifold to return warmer liquid back to CDU501. Note that CDUs501can be any kind of CDUs commercially available or customized ones. Thus, the details of CDUs501will not be described herein.

Each of the pieces of IT equipment503may include one or more IT components (e.g., central processing units or CPUs, graphical processing units (GPUs), memory, and/or storage devices). Each IT component may perform data processing tasks, where the IT component may include software installed in a storage device, loaded into the memory, and executed by one or more processors to perform the data processing tasks. At least some of these IT components may be attached to the bottom of any of the cooling devices as described above. IT equipment503may include a host server (referred to as a host node) coupled to one or more compute servers (also referred to as computing nodes, such as CPU server and GPU server). The host server (having one or more CPUs) typically interfaces with clients over a network (e.g., Internet) to receive a request for a particular service such as storage services (e.g., cloud-based storage services such as backup and/or restoration), executing an application to perform certain operations (e.g., image processing, deep data learning algorithms or modeling, etc., as a part of a software-as-a-service or SaaS platform). In response to the request, the host server distributes the tasks to one or more of the performance computing nodes or compute servers (having one or more GPUs) managed by the host server. The performance compute servers perform the actual tasks, which may generate heat during the operations.

Electronic rack500further includes optional RMU502configured to provide and manage power supplied to servers503, fan modules531, and CDU501. Optimization module521and RMC522can communicate with a controller in some of the applications. RMU502may be coupled to PSU550to manage the power consumption of the PSU. The PSU550may include the necessary circuitry (e.g., an alternating current (AC) to direct current (DC) or DC to DC power converter, backup battery, transformer, or regulator, etc.) to provide power to the rest of the components of electronic rack500.

In one embodiment, RMU502includes optimization module521and rack management controller (RMC)522. RMC522may include a monitor to monitor operating status of various components within electronic rack500, such as, for example, the pieces of IT equipment503, CDU501, and fan modules531. Specifically, the monitor receives operating data from various sensors representing the operating environments of electronic rack500. For example, the monitor may receive operating data representing temperatures of the processors, cooling liquid, and airflows, which may be captured and collected via various temperature sensors. The monitor may also receive data representing the fan power and pump power generated by the fan modules531and liquid pump512, which may be proportional to their respective speeds. These operating data are referred to as real-time operating data. Note that the monitor may be implemented as a separate module within RMU502.

Based on the operating data, optimization module521performs an optimization using a predetermined optimization function or optimization model to derive a set of optimal fan speeds for fan modules531and an optimal pump speed for liquid pump512, such that the total power consumption of liquid pump512and fan modules531reaches minimum, while the operating data associated with liquid pump512and cooling fans of fan modules531are within their respective designed specifications. Once the optimal pump speed and optimal fan speeds have been determined, RMC522configures liquid pump512and cooling fans of fan modules531based on the optimal pump speed and fan speeds.

As an example, based on the optimal pump speed, RMC522communicates with a pump controller of CDU501to control the speed of liquid pump512, which in turn controls a liquid flow rate of cooling liquid supplied to the liquid manifold525to be distributed to at least some of server blades503. Therefore, the operating condition and the corresponding cooling device performance are adjusted. Similarly, based on the optimal fan speeds, RMC522communicates with each of the fan modules531to control the speed of each cooling fan of the fan modules531, which in turn control the airflow rates of the fan modules531. Note that each of fan modules531may be individually controlled with its specific optimal fan speed, and different fan modules and/or different cooling fans within the same fan module may have different optimal fan speeds.

Note that some or all of the IT equipment503(e.g.,503A,503B,503C, and/or503D) may utilize different cooling methods. For instance, one server may utilize air cooling while another server may utilize liquid cooling. Alternatively, one IT component of a server may utilize air cooling while another IT component of the same server may utilize liquid cooling.

FIG.9is an example of a data center90according to one embodiment. Specifically, this figure shows a data center90with at least one IT room91that includes the one or more IT power modules2a-2nthat are coupled together via the DC bus4. In one embodiment, at least some of the electronic components of the modules may be positioned inside or outside the IT room. For instance, the PV panels of the modules may be positioned on a roof of the data center in order to capture solar radiation for power production.

In one embodiment, an embodiment of the disclosure may be (or include) a non-transitory machine-readable medium (such as microelectronic memory) having stored thereon instructions, which program one or more data processing components (generically referred to here as a “processor”) to IT power system operations, such as operations performed by the central controller3, the system controller9a, and/or the PV controller21. For example, the operations described herein to determine whether the configuration of the IT power module2ashould be adjusted based on whether the output voltage (e.g., open-circuit voltage) of the PV panel21exceeds a threshold voltage. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic. Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

In some embodiments, this disclosure may include the language, for example, “at least one of [element A] and [element B].” This language may refer to one or more of the elements. For example, “at least one of A and B” may refer to “A,” “B,” or “A and B.” Specifically, “at least one of A and B” may refer to “at least one of A and at least one of B,” or “at least of either A or B.” In some embodiments, this disclosure may include the language, for example, “[element A], [element B], and/or [element C].” This language may refer to either of the elements or any combination thereof. For instance, “A, B, and/or C” may refer to “A,” “B,” “C,” “A and B,” “A and C,” “B and C,” or “A, B, and C.”