Renewable energy power distribution system

A power distribution system. The power distribution system may comprise a plurality of renewable energy sources and plurality of converters to increase fault tolerance in the event of a component failure and to minimize output power degradation. Each converter may be comprised of a plurality of input ports, wherein each input port receives controlled amount of energy from the plurality of renewable energy sources. Each input port may also be disconnected in the event of component or device failure. Each of the converters is preferably configured to have additional power capacity to offset any reduced output capacity by a faulty converter, and preferably, the performance of each converter is monitored by the system to maintain its performance. The power distribution system may be monitored by a third party to maintain the energy output levels and to facilitate the power distribution system's restoration to normal functioning.

FIELD OF THE INVENTION

The present invention generally relates to power distribution systems utilizing renewable energy, and, more specifically, power distribution systems that utilize a source-sharing architecture that minimizes energy output degradation in the event of a device or component failure.

BACKGROUND OF THE INVENTION

Electric power systems generally rely on the burning of fossil fuels to meet its electrical power demands, because electrical output from steam and gas turbine generators powered by fossil fuels has been proven to be a reliable and on-demand source of energy. However, due to increasing monetary and environmental costs of the fossil fuels, there has been an increased emphasis in developing cleaner and renewable sources of power and electricity generation Examples of cleaner and renewable sources of energy include solar power, wind power, biomass power, fuel cell power, stored energy, etc. The problem with these sources is that they have not been reliable or on-demand sources for the power grid.

A conventional power distribution system generally comprises one or more renewable energy sources and one or more converters. Each individual renewable energy source is usually connected in series to form a string of renewable energy sources. In large installations, where higher input power is desired, several strings may be interconnected in parallel. The renewable energy sources are also preferably interconnected with the converters to form an overall power distribution system. Thus, when harvesting power from these renewable energy sources, each individual renewable energy source delivers to the converters an electrical voltage, which is converted into a usable form of electricity for the power grid.

Although recent technological advances have resulted in more sophisticated power distribution systems, such systems are generally not equipped to handle a device or component failure of a renewable energy source, such that the energy output is reliably provided to the power grid. For example, power distribution systems are generally designed with single-point failure modes, which may halt the entire operation of the system upon failure to a particular component of the power distribution system or renewable power source. Furthermore, the power distribution system may lack the ability to monitor the performance of the renewable power source or the power distribution system, including such performance criteria as temperature, power, current, and voltage, and the ability to maintain a minimum power output in the event of device or component failure.

Various power distribution systems have attempted to remedy the deficiencies of the currently available power distribution systems. For example, U.S. Pat. No. 8,289,742, issued to Adest et al. (“Adest I”), discloses a power distribution system comprising a plurality of renewable energy sources and a plurality of interconnected converters. The renewable energy sources are interconnected with the converters, and each individual renewable energy source delivers to the converters an electrical voltage, which is converted into a usable form of electricity. Although the power distribution system disclosed in Adest I allows the converters to share a power load with the other converters, these converters do not have ability to accommodate additional power redirected from a failed converter. The Adest I power system also lacks the ability to maintain a minimum power output in the event of component failure.

U.S. Pat. No. 8,384,243, issued to Adest et al. (“Adest II”), also discloses a power distribution system comprising a plurality of renewable energy sources and a plurality of interconnected converters. The Adest II system utilizes a temperature sensor connected to an input of a controller to adjust input power within the system. However, the system disclosed in Adest II is limited to measuring only temperature within the system and similarly lacks the ability to maintain a minimum power output in the event of component failure.

European Patent Application Number EP2533299, also filed by Adest et al. (“Adest III”), discloses a power distribution system comprising a plurality of renewable energy sources and a plurality of interconnected converters. The power distribution system disclosed in Adest III includes modules to monitor multiple parameters of each renewable energy source unit, such as current and voltage. However, like the Adest I and Adest II references, the power distribution system in Adest III does not accommodate an additional power load in the event of a converter failure.

Finally, U.S. Pat. No. 8,138,631, issued to Allen (“Allen”), discloses a power distribution system comprising a plurality of renewable energy sources that are interconnected to a plurality of converters. Allen discloses a communication bus that allows limited monitoring by a third party in the event of component failure. The Allen reference, however, does not disclose a system that can accommodate additional power loading in the event of a converter failure.

Thus, what is needed is a power distribution system that: includes a fault tolerance in the event of component failure; possesses the ability to monitor the performance of the renewable energy sources and converters; and has the ability to offset any reduced energy output resulting from a faulty device or component.

SUMMARY OF THE INVENTION

To minimize the limitations in the prior art, and to minimize other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a new and useful power distribution system.

One embodiment of the invention is a power distribution system comprising: a plurality of renewable energy sources; and a plurality of converters; wherein each of the plurality of converters is comprised of a plurality of input ports and at least one power conversion module; wherein each of the plurality of input ports are configured to connect to at least one of the plurality of renewable energy sources; wherein each of the plurality of renewable energy sources provides an input power to the plurality of input ports that are connected to the plurality of energy sources; wherein at least one power conversion module is configured to convert the input power from the plurality of renewable sources to a converted electrical energy; and wherein the plurality of converters are configured to disconnect from the plurality of renewable energy sources at the plurality of input ports. The input power from the plurality of renewable energy sources may be provided to more than one of the plurality of converters. Each of the plurality of converters may have an excess power capacity, such that the plurality of converters are configured to handle a shifted input power previously destined for another one of the plurality of converters. The plurality of converters may have a fault tolerance, such that, when one or more of the plurality of converters fail, the power distribution system shifts the input power from the one or more failed converters to one or more remaining converters of the plurality of converters in order to maintain the total output power level. The plurality of converters may be configured to disconnect from one or more failed renewable energy sources at the plurality of input ports, when one or more of the plurality of renewable energy sources fail. The one or more failed converters may be configured to disconnect from the plurality of renewable energy sources at the plurality of input ports, when one or more of the plurality of converters fail. The plurality of converters may be configured to monitor one or more parameters of one or more of the plurality of converters and the one or more parameters of one or more of the plurality of renewable energy sources. The one or more parameters may be selected from the group of parameters consisting of but not limited to: a temperature; a power; a current; and a voltage. The power distribution system may further comprise a communication bus; wherein the communication bus may be removeably connected to the plurality of converters; and wherein the communication bus may provide a plurality of data to a local or a remote user, web server or a computer application to monitor and/or control the one or more parameters. The plurality of renewable energy sources may be selected from the group of renewable energy sources consisting of but not limited to: a wind generator; a solar panel array; and solar panel strings and a combination thereof.

Another embodiment of the invention is a power distribution system comprising: a plurality of renewable energy sources; and a plurality of converters; wherein each of the plurality of converters is comprised of a plurality of input ports; wherein each of the plurality of input ports is configured to connect to at least one of the plurality of renewable energy sources, such that each of the plurality of converters is interconnected to all of the plurality of renewable energy sources; wherein each of the plurality of renewable energy sources provides an input power to each of the plurality of input ports of the plurality of converters; wherein the input power of the plurality of renewable energy sources is shared among the plurality of converters; wherein each of the plurality of converters comprises a power conversion module; wherein the power conversion module is configured to convert the input power into an output single or multi-phase AC or DC power; and wherein the output power of each of the plurality of converters is combined to achieve total output power level. Each of the plurality of converters may have an excess power capacity, such that the plurality of converters may be configured to handle a shifted input power previously destined for another one of the plurality of converters. Each of the plurality of converters may have a fault tolerance, such that, when one or more of the plurality of converters fail, the power distribution system may shift the input power from the one or more failed converters to one or more remaining converters of the plurality of converters in order to maintain a minimum output voltage level. The plurality of converters may be configured to disconnect from one or more failed renewable energy sources at the plurality of input ports, when one or more of the plurality of renewable energy sources fail. One or more failed converters may be configured to disconnect from the plurality of renewable energy sources at the plurality of input ports, when one or more of the plurality of converters fail. The plurality of converters may be configured to monitor one or more parameters of one or more of the plurality of converters and the one or more parameters of one or more of the plurality of renewable energy sources. The one or more parameters may be selected from the group of parameters consisting of but not limited to: a temperature; a power; a current; and a voltage. The power distribution system may further comprise a communication bus; wherein the communication bus may be removably connected to the plurality of converters; and wherein the communication bus may provide a plurality of data to a local or a remote user, web server or a computer application to monitor and/or control the one or more parameters. The plurality of renewable energy sources may be selected from the group of renewable energy sources consisting of but not limited to: a wind generator; a solar panel array; and solar panel strings and a combination thereof.

Another embodiment of the present invention is a power distribution system comprising: a plurality of renewable energy sources; a plurality of converters; and an external bus; wherein each of the plurality of converters is comprised of a plurality of input ports; wherein each of the plurality of input ports is configured to connect to at least one of the plurality of renewable energy sources, such that each of the plurality of converters is interconnected to all of the plurality of renewable energy sources; wherein each of the plurality of renewable energy sources provides an input power to each of the plurality of input ports of the plurality of converters; wherein the input power of the plurality of renewable energy sources is shared among the plurality of converters; wherein each of the plurality of converters comprises a power conversion module; wherein the power conversion module is configured to convert the input power into a single or multi-phase AC or DC output power; wherein the output power of each of the plurality of converters is combined to achieve total output power level; wherein each of the plurality of converters has an excess power capacity, such that the plurality of converters are configured to handle a shifted input power previously destined for another one of the plurality of converters; wherein the plurality of converters has a fault tolerance, such that, when one or more of the plurality of converters fail, the power distribution system shifts the input power from the one or more failed converters to one or more remaining converters of the plurality of converters in order to maintain the total output power level; wherein the plurality of converters are configured to disconnect from one or more failed renewable energy sources at the plurality of input ports, when one or more of the plurality of renewable energy sources fail; wherein one or more failed converters are configured to disconnect from the plurality of renewable energy sources at the plurality of input ports, when one or more of the plurality of converters fail; wherein the plurality of converters are configured to monitor one or more parameters of one or more of the plurality of converters and the one or more parameters of one or more of the plurality of renewable energy sources; wherein the communication bus is removably connected to the plurality of converters; wherein the communication bus provides a plurality of data to a local or a remote user, web server or a computer application to monitor and control the one or more parameters; wherein the one or more parameters are selected from the group of parameters consisting of: a temperature; a power; a current; and a voltage; and wherein the plurality of renewable energy sources is selected from the group of renewable energy sources consisting of but not limited to: a wind generator; a solar panel array; and solar panel strings and a combination thereof.

The power distribution system of the present invention may comprise: a plurality of renewable energy sources; a plurality of converters, wherein each converter may comprise a plurality of input ports; one or more controlled power draw modules; a mixer; a power conversion module; and an output port. The renewable energy sources are preferably one or more technologies that utilize replenishable energy sources such as energy from water, wind, the sun, geothermal sources, and biomass sources (e.g., energy crops). Examples of such renewable energy sources may include, without limitation, wind turbines, hydroelectric power stations that utilize hydroelectricity and hydropower, solar panels, solar arrays, cogeneration plants that utilize biomass materials, biofuels, biodiesels, geothermal energy, and the like.

It is an object of the present invention to provide a plurality of converters that combine the input power of one or more renewable energy sources to achieve total output power level.

It is an object of the present invention to provide a power distribution system that minimizes energy output degradation in the event of a device or component failure.

It is a further object of the present invention to provide a power distribution system that has one or more converters, wherein the converters have excess power capacity, such that the power distribution system may shift and store input power from a failed converter to one or more remaining properly functioning converters.

It is a further object of the invention to provide a power distribution system with a fault tolerance, such that, when one of the plurality of converters fail, the remaining converters may maintain the total output power level by shifting the input power obtained from a plurality of renewable energy sources from the failed converter to the remaining, properly functioning converters.

It is a further object of the invention to provide a converter with one or more input ports that are disconnectable from the renewable energy sources in the event of a device or component failure.

It is a further object of the invention to provide a power distribution system that monitors the parameters of the renewable power sources, such as temperature, power, current, and voltage.

It is a further object of the invention to provide a power distribution system that is able to be externally monitored and controlled. The external monitoring preferably monitors and controls the parameters of the renewable power sources or the parameters of the power distribution system.

It is a further object of the invention to provide a power distribution system that generates single or multi-phase AC and/or DC power from a plurality of renewable energy sources.

It is a further object of the invention to overcome the deficiencies of the prior art.

These, as well as other components, steps, features, objects, benefits, and advantages, will now become clear from a review of the following detailed description of illustrative embodiments, of the accompanying drawings, and of the claims.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following detailed description of various embodiments of the invention, numerous specific details are set forth in order to provide a thorough understanding of various aspects of one or more embodiments of the invention. However, one or more embodiments of the invention may be practiced without some or all of these specific details. In other instances, well-known procedures and/or components have not been described in detail so as not to unnecessarily obscure aspects of embodiments of the invention.

While some embodiments are disclosed here, still other embodiments of the present invention will become obvious to those skilled in the art as a result of the following detailed description of embodiments of the invention. The invention is capable of modifications of various obvious aspects, all without departing from the spirit and scope of the present invention. The Figures, and their detailed descriptions, are to be regarded as illustrative in nature and not restrictive. Also, the reference or non-reference to a particular embodiment of the invention shall not be interpreted to limit the scope of the invention.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in another embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.

Definitions

In the following description, certain terminology is used to describe certain features of one or more embodiments of the invention. For example, as used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. Additionally, the terms “wire” and “cable” are generally used synonymously unless otherwise noted.

As used herein, the term “device”, “computer”, “electronic data processing unit”, “invention server”, or “server” generally refers to any device that processes information with an integrated circuit chip, including without limitation, personal computers, mainframe computers, workstations, servers, desktop computers, portable computers, laptop computers, embedded computers, wireless devices including cellular phones, personal digital assistants, tablets, tablet computers, smart phones, portable game players, and hand-held computers. The term “internet” refers to any collection of networks that utilizes standard protocols, whether Ethernet, Token ring, Wifi, asynchronous transfer mode (ATM), Fiber Distributed Data Interface (FDDI), code division multiple access (CDMA), global systems for mobile communications (GSM), long term evolution (LTE), or any combination thereof. The term “communication bus” generally refers to a duplicated, redundant and single or multi-channel multi-point bi-directional data paths for exchange of data between plurality of nodes. Nodes are preferably the exchange point for any transaction of data to/from a module, block or a unit within or outside the system.

As used herein, the term “renewable energy source” generally refers to one or more technologies that utilize replenishable energy sources such as energy from water, wind, the sun, geothermal sources, and biomass sources such as energy crops. Such renewable energy sources may include without limitation, a wind generator, a solar panel array, solar panel strings, wind turbines, hydroelectric power stations that utilize hydroelectricity and hydropower, solar panels, solar arrays, cogeneration plants that utilize biomass materials, biofuels, biodiesels, geothermal energy, and a combination thereof.

As used herein, the terms “alternating current” and “AC” generally refer to a current where the flow of electric charge periodically reverses direction. The terms “direct current” and “DC” generally refer to a current where electric charge only flows in one direction.

As used herein, the term “independent device” generally refers to any device apart from the power distribution system that does not function with the converters to combine the input power of the one or more renewable energy sources nor achieve or maintain the total output power level of the converters. Preferably, the independent device is configured to provide data information of the power distribution system to local or remote users and may allow a local or remote user to monitor and control one or more parameters of the power distribution system. The device may be any electronic data processing unit such as a web server and may include one or more computer applications.

FIG. 1is a block diagram of one embodiment of the power distribution system. As shown inFIG. 1, one embodiment of the power distribution system100may comprise: a plurality of renewable energy sources102,104,106and a plurality of converters180,182,184, wherein each converter180,182,184may comprise a plurality of input ports120,122,124,126,128,130,132,134,136; one or more controlled power draw modules140,142,144,146,148,150,152,154,156; a mixer160,162,164; a power conversion module170,172,174, and an output port176,177,178. The renewable energy sources102,104,106are preferably one or more technologies that utilize replenishable energy sources such as energy from water, wind, the sun, geothermal sources, and biomass sources (e.g., energy crops). Examples of such renewable energy sources102,104,106may include, without limitation, wind turbines, hydroelectric power stations that utilize hydroelectricity and hydropower, solar panels, solar arrays, cogeneration plants that utilize biomass materials, biofuels, biodiesels, geothermal energy, and the like.FIG. 1also shows that converter184, titled “Converter N” may represent more than one converter.

A converter180,182,184or power converter is preferably any device that changes the current or voltage from one source of an electrical power and/or may be combined with other components to generate output power in the desired form of DC or AC voltages or currents. AC power can be in the form of a single phase or a multi-phase voltages and/or currents. A converter180,182,184may be used to convert a varying current or voltage input from a source to a regulated output with a constant level of voltages in the form of AC or DC power. For example, a converter180,182,184may change the input voltage from 50V to 600V DC input from a renewable energy source to an output voltage of 400V regulated DC. Similarly, a converter may change an input voltage from 400V DC to a 120V single phase AC power or a 24V to 300V variable DC input to a steady 240V three phase AC output. A converter may also combine other input voltages to produce a larger or smaller output voltage.

As discussed above, each converter preferably comprises a plurality of input ports120,122,124,126,128,130,132,134,136; one or more controlled power draw modules140,142,144,146,148,150,152,154,156; a mixer160,162,164; a power conversion module170,172,174, and an output power port176,177,178. The input ports120,122,124,126,128,130,132,134,136are preferably configured to receive an input power from the renewable energy sources102,104,106. The controlled power draw modules140,142,144,146,148,150,152,154,156are preferably any component or circuit, which functions as a current regulator that controls the net current flow from its input to its output terminals. Each of the controlled power draw modules140,142,144,146,148,150,152,154,156is preferably configured to have an excess current capacity to accommodate the input power from the other converters, and this excess current capacity preferably provides an extended tolerance to power failures by shifting an input power from one converter or a controlled draw module to another in the event a converter or component fails. The mixer160,162,164is preferably any component or circuit used to combine one or more input voltages or currents into a common bus, and the power conversion module170,172,174is preferably one or more components or circuits used to convert power from one voltage form to another. The output power ports176,177,178are preferably where the output power is delivered to the grid or designated load via final power output190.

FIG. 1shows that the renewable energy sources102,104,106are preferably interconnected to the input ports120,122,124,126,128,130,132,134,136of the converters180,182,184and preferably produce an input power, which is received at the input ports120,122,124,126,128,130,132,134,136of the converters180,182,184. Each converter180,182,184is preferably configured to have an excess power capacity to accommodate the input power from the other converters, and this excess power capacity preferably provides an extended tolerance to power failures by shifting an input power from one converter to another in the event a converter or component fails. For example, in one embodiment, a converter configured to take an input power of 1000 watts, which is 50% of its rated power capacity, may accommodate the additional input power of another converter rated with the same amount of power or less. This extra power capacity to take on an additional power input from the renewable energy sources102,104,106is preferably accomplished by the amount of input power drawn by each controlled power draw module140,142,144,146,148,150,152,154,156. After the input power for each renewable energy source102,104,106has been drawn by each corresponding controlled power draw module140,142,144,146,148,150,152,154,156, the input power is preferably combined by the mixer160,162,164and is preferably converted by the power conversion module170,172,174to its desired output voltage. This desired voltage is usually then sent out through the output power port176,177,178of each converter180,182,184and is preferably combined to create a final power output190.

FIG. 1also shows that the input ports120,122,124,126,128,130,132,134,136of each converter180,182,184may be connected to at least one of the renewable energy sources102,104,106, such that every converter180,182,184is interconnected to all of the renewable energy sources102,104,106. This configuration preferably creates a fault tolerance, which enables the power distribution system100to continue its normal and intended operation, rather than failing, partially or completely, when one or more of the devices or components of the system fails. Specifically, when a converter fails, the other converters preferably redirect the input power of the failed converter to the functioning converters. The functioning converters are preferably configured to carry this larger amount of input power, some of which was intended to be directed to the failed converter. Preferably, each converter180,182,184is configured to disconnect its input ports120,122,124,126,128,130,132,134,136from the renewable energy sources102,104,106, and, when an input port is disconnected, the input power derived from that input power is redirected to one or more of the remaining converters and is preferably combined with the other input voltages.

The fault tolerance of the power distribution system allows the system to maintain the total output power level in the event of one or more of the converters failing. The remaining converters may maintain the total output power level by shifting the input power obtained from a plurality of renewable energy sources from the failed converter to the remaining, properly functioning converters.

Furthermore, each converter180,182,184preferably possesses the ability to internally monitor one or more of the parameters of each renewable energy sources102,104,106or each converter180,182,184(shown inFIG. 3). After each converter180,182,184internally monitors its own performance that converter may share the parameter data with the remaining converters. Additionally, one or more converters180,182,184or renewable energy sources102,104,106may be externally monitored by a local or a remote user, web server or a computer application via a communication bus. These parameters may include, without limitation, temperature, power, input current, input voltage, and available voltage. AlthoughFIG. 1shows only three renewable energy sources and three converters, it should be understood that any number of renewable energy sources and converters may be used without deviating from the scope of the invention.

FIG. 2is a block diagram of another embodiment of the power distribution system and shows the power distribution system comprising multiple power distribution systems. As shown inFIG. 2, another embodiment of the power distribution system200may comprise: a first renewable energy source202, second renewable energy source204, third renewable energy source206, fourth renewable energy source208, first converter280, second converter282, third converter284, and fourth converter286. Preferably, each converter280,282,284,286may comprise: a plurality of input ports220,222,224,226,228,230,232,234; one or more controlled power draw modules240,242,244,246,248,250,252,254; a mixer260,262,264,266; a power conversion module270,272,274,276; and an output port276,277,278,279.FIG. 2shows that, rather than having all of the renewable energy sources202,204,206,208interconnected with the input ports220,222,224,226,228,230,232,234, the renewable energy sources202,204,206,208and converters280,282,284,286may be broken up into groups. For example, as shown inFIG. 2, the first renewable energy source202and second renewable energy source204may be interconnected with the input ports220,222,224,226of the first converter280and second converter282as one power distribution system or group. Similarly, the third renewable energy source206and fourth renewable energy source208may be interconnected with the input ports228,230,232,234, the third converter284, and fourth converter286as a second power distribution system or group. Thus, this configuration shows that multiple power distributions systems may be interconnected to produce a single power output290. AlthoughFIG. 2shows only two power distribution systems, each with two renewable energy sources and two converters, it should be understood that any number of power distribution systems, renewable energy sources, and converters may be used without deviating from the scope of the invention.

FIG. 3is a block diagram of another embodiment of the power distribution system and shows the parameters that are monitored among the converters via interconnections. As shown inFIG. 3, another embodiment of the power distribution system300may comprise: a plurality of converters380,382,384; a plurality of interconnections310,312,314; and a communication bus390. As discussed above, the converters380,382,384are preferably configured to monitor one or more parameters internally and/or externally. Specifically, each converter is preferably configured to monitor temperature322,324,326; voltage332,334,336; and current342,344,346. This may be accomplished through sensors built-in into each converter via one or more interconnections310,312,314. Further, the interconnections310,312,314may be physical wires or cables, or a wireless system such as Bluetooth or Wi-Fi. Like the interconnections310,312,314, a communication bus390preferably allows a local or a remote user, web server or a computer application to externally monitor the parameters via a computer or electronic data processing unit. This will preferably allow a third party to be able to quickly find a faulty device or component.

FIG. 4is a schematic of one embodiment of the controlled power draw module. As shown inFIG. 4, one embodiment of the controlled power draw module400may include: a local communication bus405; transistor410; input voltage415; inductor voltage425; input current430; voltage output435; output current438; a first diode440; inductor445; second diode450; microcontroller460; relay455; capacitor465; and gate driver470. As discussed above, the controlled power draw module400is preferably a circuit or component, which functions as a current regulator that controls the net current flow from its input to its output terminals. The controlled power draw module400is preferably commanded by the power conversion module170,172,174,270,272,274,276,500(shown in detail inFIG. 5) via a supervisory controller525(shown inFIG. 5). A single power conversion module170,172,174,270,272,274,276,500may also control multiple controlled power draw modules within a converter without deviating from the scope of the invention.

In particular, the power conversion module170,172,174,270,272,274,276,500preferably sends commands to the microcontroller460of the controlled power draw module400via a local communication bus405. In response, the microcontroller460generates a pulse width control signal or stream of control pulses that effectively controls the regulated current flow of the controlled power draw module400. The pulse width control signal is preferably generated by the microcontroller460based on regulation algorithms, and the microcontroller460preferably performs the current regulation via pulse width modulator by controlling a switching circuit in the controlled power draw module400. In one embodiment, as shown inFIG. 4, the switching circuit may comprise a transistor410Q1, first diode440D1, inductor445L1, and capacitor465C1. The pulse width modulator signal controls the switching function of the circuit by controlling the input gate signal of transistor410Q1and may also be further driven by a gate driver470to increase its signal generated by the microcontroller460.

The controlled power draw module400may also include a second diode450D2, which generally provides dual functions. First, it preferably provides a summing point at the output terminal to combine outputs from all local controlled power draw modules without any extra components. Second, the second diode450D2also preferably provides isolation to prevent reverse current flow back into the controlled power draw module400.

Regarding the microcontroller460, various embodiments of a microcontroller may include a modern processor chip such as ARM Cotex-M4 chip, which has a built-in floating point processor, or an ARM Cortex-M4 chip from ST microelectronics. In one embodiment, the microcontroller460may be an ARM Cortex-M4 chip due to its built-in on-board peripheral circuits such as analog-to-digital converters, pulse-width modulators, and timers. The ARM Cortex-M4 chip also generally includes a direct memory access module, which may further relieve the control processing unit from peripheral servicing overheads, thereby leaving much needed resources for actual computations and high level controls and functions.

As discussed above, multiple controlled power draw modules within a converter module may be controlled by a single power conversion module170,172,174,270,272,274,276,500. This is preferably accomplished through the use of a local communication bus405, which preferably extends across the power conversion module170,172,174,270,272,274,276,500locally without extending further to other power conversion modules. Additionally, communication between the power conversion module170,172,174,270,272,274,276,500and components outside the power distribution system100,200,300may take place through the system communication bus805(shown inFIG. 8), which is separately available at the supervisory controller525located within the power conversion module170,172,174,270,272,274,276,500.

When monitoring its performance, the microcontroller460may send out status signals to the power conversion module170,172,174,270,272,274,276,500. Specifically, the microcontroller460may send actual values of observed analog variables and suspected fault conditions such as major and minor faults to the power conversion module170,172,174,270,272,274,276,500via the local communication bus405. Such major faults are generally those faults that require shutdown of the controlled power draw module. Minor faults, on the other hand, are generally those faults that require some attention to prevent a major fault from occurring (e.g., rising temperatures or significant efficiency loss).

In a preferred embodiment, the controlled power draw module400can implement two modes of current regulation. Specifically, one mode of current regulation may use a dominant feed forward control with discontinuous conduction mode. The second mode of current regulation may use a feedback current controlled loop with continuous conduction mode. The first mode of current regulation, which utilizes the feed forward control, is generally preferred in situations where a computation is made periodically to calculate the pulse width control timing of the transistor410Q1based on the commanded current value Icmd. The calculated pulse width control timing generally results from the input voltages and currents such as positive input voltage415Vin, inductor voltage425VL, input current430Iin, output current438Ioutand voltage output435Vout. The feed forward control mode may also take into account a temperature value in the vicinity of the power stressed components such as transistor410Q1, first diode440D1, inductor445L1and second diode450D2. A secondary current control loop may also be implemented to control alongside the feed-forward control to correct small deviations caused by tolerances and temperature.

With the feed-forward control mode, in approximately every few microseconds, a computation may be made resulting from equations of a system model which closely matches the actual hardware circuit of the controlled power draw module400. These equations generally govern the behavior of the circuit with the given values of voltages and currents around the controlled power draw module400. The resultant value of the pulse width modulator control value may be used in conjunction with the secondary control loop to achieve fast and accurate response to the perturbations that happen during the course of the system life under different operating conditions.

FIG. 4also shows how the controlled power draw module400may disconnect input ports or itself from the renewable energy source. Specifically, normally open relay455preferably enables the controlled power draw module400to disconnect itself from a renewable energy source, thereby protecting system against internal failure inside the controlled power draw module400or power conversion module500.

FIG. 5is a schematic of one embodiment of the power conversion module. As shown inFIG. 5, one embodiment of the power conversion module500may include: a local communication bus405; the supervisory controller525; and three major modules—i.e., a phase shifted isolated full bridge converter510, three-phase pulse-width modulator converter515, and pulse-width modulator filter, contactor & net-metering module520. The phase shifted isolated full bridge converter510, three-phase pulse-width modulator converter515, and pulse-width modulator filter, contactor & net-metering module520generally work together under direct control of the supervisory controller525, even though the isolated full bridge converter510and three-phase pulse-width modulator converter515may have their own microcontrollers for internal functionality.

The phase shifted isolated full bridge converter510is generally built on a phase-shifted topology with zero-voltage switch modes to enhance efficiency and reliability. The primary function of the phase shifted isolated full bridge converter510is preferably to provide galvanic isolation between the three-phase alternating current output circuitry and renewable energy source tied circuitry. The phase shifted isolated full bridge converter510also may generate an appropriate high voltage bus to power the three-phase converter. The phase shifted isolated full bridge converter510preferably has its own local microcontroller to implement switching topology and generally generates high voltage direct current Bus (HVBUS) as commanded by the supervisory controller525. Furthermore, the phase shifted isolated full bridge converter510may also report back full status of its operation to the supervisory controller525via the local communication bus505.

The three-phase pulse-width modulator converter515preferably generates a three-phase alternating current modulation in the form of pulse width modulated outputs converted from the HVBUS. The three-phase pulse-width modulator converter515preferably also has its own microcontroller and, like the phase shifted isolated full bridge converter510, the three-phase pulse-width modulator converter515generally functions as commanded by the supervisory controller525. For proper connection to the power grid, the three-phase pulse-width modulator converter515generally monitors the three-phase line voltages and currents in real time and preferably locks in the desired frequency, phase and amplitude accordingly, so that a controlled amount of power is transferred to the power grid.

Three-phase pulse-width modulator converter515also preferably performs a net-metering via the dedicated circuitry located inside the pulse-width modulator filter, contactor & net-metering module520. Alternatively, net-metering may be implemented as a software function inside the dedicated microcontroller of the three-phase pulse-width modulator converter515. Because net-metering chips generally have multiple built-in analog-to-digital converters to measure the three-phase voltages and currents, alongside the net-metering functions, utilizing a net-metering chip is generally more cost effective due to its built-in functions, rather than, implementing complexity hardware for the analog front-end. Furthermore, safety is generally ensured by proper control of contactors installed as part of the output section of the pulse-width modulator filter, contactor & net-metering module520. One important aspect of three-phase pulse-width modulator converter515is generally its complete galvanic isolation of all electrical signals to and from other sections of the power distribution system, such as the isolation of connections to the local communication bus505and isolation for direct current power supply for operating its own microcontroller and associated interfaces. Like other parts of the power distribution system100,200,300, the pulse-width modulator converter515may report a complete status along with net-metering data to the supervisory controller525.

The output of the pulse width modulator is generally fed into the pulse-width modulator filter, contactor & net-metering module520to remove a modulation carrier and to generate a clean sinewave alternating current output power to the grid terminals via the contactor circuit Together with the net-metering circuits, the overall power conversion module500generally achieves controlled transfer of alternating current power to the power grid.

Regarding situations of a malfunction or a failure, the contactors may disconnect and isolate the power grid from the power conversion module500. The contactors may also allow the power conversion module500to synchronize itself to the power grid before applying alternating current power onto the grid. The contactors are controlled by the microcontroller located in the three-phase pulse-width modulator converter515.

Turning to the supervisory controller525, the supervisory controller525preferably has a powerful set of resources at its disposal including a fast microcontroller (e.g., ARM Cortex-M4) with a large amount flash memory, random access memory, and multiple channels of various types of communication peripherals. The supervisory controller525also preferably carries an extensive set of other hardware peripherals such as timers, analog-to-digital converters, and direct memory access.

In a preferred embodiment, the supervisory controller525performs a vital function, which is implementing a source sharing principal of the power distribution system100,200,300. The supervisory controller525preferably has two major operations. First, the supervisory controller525preferably controls multiple controlled power draw modules that are local to the converter in order to feed the local power conversion module. Second, the supervisory controller525preferably interacts with other converters of the power distribution system100,200,300to ensure maximum power generation with optimum utility of available power from the renewable energy sources via effective sharing among available controlled power draw modules and power conversion modules located in each individual converter. Each supervisory controller525in the power distribution system100,200,300is preferably aware of the overall system status and generally works under the concept of collective intelligence—that is, all supervisory controllers work collectively to strengthen system reliability and performance by being aware of the whole system and acting in harmony as if it was one operating environment. There is preferably a dedicated and duplicated system communication bus805(shown inFIG. 8) across all supervisory controllers in the power distribution system100,200,300to ensure maximum reliability and performance.

In various embodiments, one primary aspect of the design of the power distribution system100,200,300is the distribution of each renewable energy output across multiple converters. That way not only a uniform distribution of available power is achieved across these converters, but also, the design of the power distribution system100,200,300provides each supervisory controller525with an ability to linearly adjust its own share of power generation, thereby improving reliability against long term failures, which mostly occur due to continuous stress factors appearing on different system components. This principal is in sharp contrast with conventional power distribution systems, which work on the basis of switching in and out individual backup or redundant modules in case of a failure. Each individual converter can partially or entirely relieve itself from its power share temporarily depending on the underlying cause or a problem. Additionally, the converters are preferably configured to perform this for routine maintenance purposes while still generating full power by allowing the remaining converters to take a larger share of available energy from the renewable energy sources. To implement the source sharing principal, software functions in the supervisory controller525in the example embodiment are executed under a multitasking environment, wherein multiple tasks are running concurrently.

FIG. 6is a simplified flow chart of one embodiment of the startup for the supervisory controller. As shown inFIG. 6, one embodiment of process startup for the supervisory controller600may comprise the steps of: initializing the power distribution system memories and peripherals610; finding all of local controlled power draw modules and establishing a communication with those local controlled power draw modules615; finding the presence of a local power conversion module and establish a communication with the local power conversion module620; creating and populating own status image in the local memory as a converter unit625; finding the presence of all the remaining converters in the power distribution system and establishing communication with those remaining converters630; and launching a periodic auto-updating process for all images in the local memory635. Specifically, the supervisory controller525may initially startup the power distribution system memories and peripherals610. This is generally supplemented by running a built-in self-test within the power distribution system100,200,300. The supervisory controller525then preferably finds all of local controlled power draw modules and establishes a communication with those local controlled power draw modules615. This step may include the process of creating and populating status images in the local memory for each controlled power draw module. After communication is established with the local controlled power draw modules, the supervisory controller525locates the presence of a local power conversion module and establishes a communication with the local power conversion module620. Like the previous step, this step may include the process of creating and populating a power conversion module status image in its own memory. The supervisory controller525then creates and populates own status image in the local memory as a converter unit625. This may require the supervisory controller525to announce via the system communication bus805(shown inFIG. 8) its own presence and broadcast its own status to the other converters. Next, the supervisory controller525finds the presence of the remaining converters in the power distribution system and establishes communication with those remaining converters630. The supervisory controller525may then create and populate status images in the local memory for each of the converters. Once the supervisory controller525launches a periodic auto-updating process for all the images in the local memory635, the supervisory controller525may also launch the source sharing control application process and a continuous self-health check process. AlthoughFIG. 6shows six steps, it should be understood that additional steps may be included without deviating from the scope of the invention.

FIG. 7is a flow chart of one embodiment of the process for simplifying source sharing control of a single controlled power draw module. As shown inFIG. 7, one embodiment of the process for simplifying source sharing control of a single controlled power draw module700may comprise the steps of: computing the total available power from one renewable energy source and the combined power shared by the other controlled power draw modules710; computing the balanced power for that particular controlled power draw module715; computing the value of the regulated current for the local controlled power draw720; sending the regulated current value to the controlled power draw module725; and updating the status image for the controlled power draw module and power conversion module by sending the new status to the other converters730. Specifically, regarding the step of computing the total available power from one renewable energy source and the combined power shared by the other controlled power draw modules710, the power distribution system100,200,300preferably computes Pt, which is the total available power from one renewable energy source. The power distribution system100,200,300also preferably computes the power shared by the other controlled power draw modules Pcby calculating the combined power shared among the other controlled power draw modules from that particular renewable energy source. Given values Ptand Pc, the power distribution system100,200,300then performs the next step, which is computing the balanced power for that particular controlled power draw module715. This is generally calculated through the following equation:
Pb=Pt−Pc
Once the balanced power Pbis calculated, the power distribution system100,200,300generally performs the next step, which is computing the value of the regulated current for the local controlled power draw720. The value of the regulated current Icmdcan be calculated with the following equation:
Icmd=Pb/Vin
The Icmdvalue is then sent to that controlled power draw module (i.e., sending the regulated current value to the controlled power draw module725), and the power distribution system100,200,300preferably updates the status image for the controlled power draw module and power conversion module. Further, this status image is also sent to the other converters—i.e., updating the status image for the controlled power draw module and power conversion module by sending the new status to the other converters730. AlthoughFIG. 6shows five steps, it should be understood that additional steps may be included without deviating from the scope of the invention.

FIG. 8is a block diagram of one embodiment of the remote access and user interface module for the power distribution system. As shown inFIG. 8, one embodiment of the remote access and user interface module800may comprise: a system communication bus805; system access controller and interface circuits810; wired local area network port815; serial to Wi-Fi and Bluetooth module820; antenna825; and direct user interface control panel830. The remote access and user interface module800is preferably a gateway between the power distribution system100,200,300and the local user or third party and is typically designed on a high performance control processing unit with large memory and a strong set of communication ports and hardware peripherals.

In one embodiment, a user may connect to the power distribution system100,200,300in several ways. First, a user may access the power distribution system100,200,300through a direct user interface control panel830, which is preferably an interface with a control panel, display, and keypad. The control panel generally provides one or more local computer wired connection ports through a universal serial bus or RS-232 serial connections, and a dedicated application preferably runs on a user laptop or a personal computer to facilitate advanced interaction with the power distribution system100,200,300.

In another embodiment, a user may also have access to the power distribution system100,200,300through a wired or wireless network. A user may have wireless access to the power distribution system100,200,300through a serial to Wi-Fi and Bluetooth module820via antenna825inside the remote access and user interface module800. Alternatively, a user can also connect to the power distribution system100,200,300using a smartphone, laptop, or tablet computer using a Wi-Fi or Bluetooth wireless connection. A remote client or server can also be connected to the power distribution system100,200,300through a wireless access point via WiFi network (i.e., serial to wifi and Bluetooth module820) or through the wired local area network port815. Regarding wired networks, a wired local area network port815may be provided for connection to an existing local area network (LAN) if available at the installation site.

Regarding remote access, the power distribution system100,200,300may also provide a user with remote access through several mechanisms. A user, for instance, may directly login into the power distribution system100,200,300from a remote location via internet using TCP/IP, UDP, Telenet connection, or some other protocol. Alternatively, a remote host may directly connect to the power distribution system100,200,300securely in real-time, with a dedicated web server, which continuously records and monitors the system performance and generates web portals for authorized users. Authorized users can also access the status of the power distribution system100,200,300or connect remotely via any such method and interact with the system as may be needed.

In a preferred embodiment, the remote access and user interface module800generally continuously monitors system status and events and sends out respective alarms if needed. The remote access and user interface module800preferably facilitates remote diagnostics access to allow maintenance personnel to access information about the system performance and devise any required adjustments to the system parameters. If any problems occur with the power distribution system100,200,300, any maintenance personnel or authorized user preferably locates the problem and performs any troubleshooting or repair, if required.

The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the above detailed description, which shows and describes illustrative embodiments of the invention. The invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the detailed description is to be regarded as illustrative in nature and not restrictive. Also, although not explicitly recited, one or more embodiments of the invention may be practiced in combination or conjunction with one another. Furthermore, the reference or non-reference to a particular embodiment of the invention shall not be interpreted to limit the scope of the invention. It is intended that the scope of the invention not be limited by this detailed description, but by the claims and the equivalents to the claims that are appended hereto.