阅读说明：本技术 混合通用负载调节器 (Hybrid universal load regulator ) 是由 K·帕西乌拉 E·欧内斯特 于 2018-10-18 设计创作，主要内容包括：发电系统包括发电机组、开关装置、电存储装置、第一逆变器、第二逆变器以及控制器。该开关装置包括连接到发电机组的输入端子和连接到负载的输出端子。第一逆变器连接在输入端子和电存储装置之间。第二逆变器连接在输出端子与电存储装置之间。控制器可通信地联接至发电机组、开关装置、第一逆变器以及第二逆变器。控制器被配置为确定外部电源是否正在向负载供电,如果没有,则控制器以第一状态运行发电系统。如果外部电源正在向负载供电,则控制器以第二状态运行发电系统。(The power generation system includes a genset, a switching device, an electrical storage device, a first inverter, a second inverter, and a controller. The switching device includes an input terminal connected to the genset and an output terminal connected to a load. The first inverter is connected between the input terminal and the electrical storage device. The second inverter is connected between the output terminal and the electrical storage device. The controller is communicatively coupled to the genset, the switching device, the first inverter, and the second inverter. The controller is configured to determine whether the external power source is supplying power to the load, and if not, the controller operates the power generation system in a first state. The controller operates the power generation system in a second state if the external power source is supplying power to the load.)

1. A power generation system, comprising:

a generator set including an engine;

a switching device including an input terminal connected to the genset and an output terminal configured to be connected to a load;

an electrical storage device;

a first inverter connected between the input terminal of the switching device and the electrical storage device;

a second inverter connected between an output terminal of the switching device and the electrical storage device; and

a controller communicatively coupled to the generator set, the switching device, the first inverter, and the second inverter, the controller configured to:

determining whether an external power source is supplying power to the load;

in response to determining that the external power source is not supplying power to the load, operating the power generation system in a first state in which:

an engine of the generator set operates at a first speed;

closing the switching device to connect the generator set to the load; and

the generator set charging the electrical storage device through at least one of the first inverter or the second inverter; and

in response to determining that the external power source is supplying power to the load, operating the power generation system in a second state in which:

the engine is operated at a second speed lower than the first speed;

-opening the switching means; and

the genset supplies power to the load through the first inverter and the second inverter, wherein the first inverter functions as a rectifier.

2. The power generation system of claim 1, wherein the controller is further configured to:

detecting whether the external power source is added to supply power to the load; and

in response to detecting the addition of an external power source, switching the power generation system from the first state to the second state by:

reducing a speed of an engine of the generator set from the first speed to the second speed;

using the first inverter as a rectifier; and

opening the switching device.

3. The power generation system of claim 1, wherein the controller is further configured to:

detecting that the external power source has been removed; and

in response to detecting that the external power source has been removed, switching the power generation system from the second state to the first state by:

configuring the electrical storage device to supply power to the load;

increasing a speed of an engine of the generator set from the second speed to the first speed; and

closing the switching device.

4. The power generation system of claim 1, further comprising: a sensing device communicatively coupled to the controller, the sensing device configured to measure a voltage level at the output terminal of the switching device, the measured voltage level providing an indication that the external power source is powering the load.

5. The power generation system of claim 1, wherein in response to determining that the external power source does not meet load requirements when the power generation system is operating in the second state, the controller is configured to switch from the second state to the first state by:

configuring the generator set to increase a speed of the engine to the first speed;

supplying power from the generator set to the load through the first inverter and the second inverter, wherein the first inverter is configured to function as a rectifier and the second inverter is configured to synchronize power with a load;

connecting the generator set to the load through the switching device in response to determining that an engine of the generator set is operating at the first speed; and

operating the power generation system in the first state.

6. The power generation system of claim 1, wherein in response to determining that the external power source is meeting a load demand when the power generation system is operating in the first state, the controller is configured to switch from the first state to the second state by:

disconnecting the generator set from the load by the switching device;

providing a control input to the generator set to reduce the engine speed to the second speed; and

operating the power generation system in the second state.

7. The power generation system of claim 1, wherein the second state further comprises:

charging the electrical storage device through the generator set.

8. The power generation system of claim 1, wherein the controller is further configured to operate the power generation system in an alternative mode when an engine of the generator set is off, the alternative mode comprising:

determining an increased load demand or a decreased load demand; and

providing, by the second inverter, power from the external power source to the electrical storage device in response to determining a reduced load demand.

9. The power generation system of claim 8, wherein the generator set further comprises an alternator, and wherein the controller is further configured to, in response to determining an increased load demand:

supplying power from the electrical storage device to the load through the second inverter;

supplying power from the electrical storage device to the alternator through the first inverter;

providing a control input to the generator set to start the engine; and

connecting the generator set to the load through the switching device in response to determining that an engine of the generator set is operating at the first speed.

10. A controller for an electrical power generation system, the controller communicably coupled to a generator set, a switching device, a first inverter, a second inverter, and an electrical storage device, the controller configured to:

determining whether an external power source is supplying power to a load;

in response to determining that the external power source is not supplying power to the load, operating the power generation system in a first state in which:

an engine of the generator set operates at a first speed;

closing the switching device to connect the generator set to the load; and

the generator set charging the electrical storage device through at least one of the first inverter or the second inverter; and

in response to determining that the external power source is supplying power to the load, operating the power generation system in a second state in which:

the engine is operated at a second speed lower than the first speed;

-opening the switching means; and

the genset supplies power to the load through the first inverter and the second inverter, wherein the first inverter functions as a rectifier.

11. The controller of claim 10, wherein the controller is further configured to:

detecting whether the external power source is added to supply power to the load; and

in response to detecting the addition of an external power source, switching the power generation system from the first state to the second state by:

reducing a speed of an engine of the generator set from the first speed to the second speed;

using the first inverter as a rectifier; and

the switching device is opened.

12. The controller of claim 10, wherein the controller is further configured to:

detecting to remove the external power source; and

in response to detecting that the external power source has been removed, switching the power generation system from the second state to the first state by:

configuring the electrical storage device to supply power to the load;

increasing a speed of an engine of the generator set from the second speed to the first speed; and

closing the switching device.

13. The controller of claim 10, wherein in response to determining that the external power source does not meet load requirements when the power generation system is operating in the second state, the controller is configured to switch from the second state to the first state by:

configuring the generator set to increase a speed of the engine to the first speed;

supplying power from the generator set to the load through the first inverter and the second inverter, wherein the first inverter is configured to function as a rectifier and the second inverter is configured to synchronize power with a load;

connecting the generator set to the load through the switching device in response to determining that an engine of the generator set is operating at the first speed; and

operating the power generation system in the first state.

14. The controller of claim 10, wherein in response to determining that the external power source is meeting a load demand when the power generation system is operating in the first state, the controller is configured to switch from the first state to the second state by:

disconnecting the generator set from the load by the switching device;

providing a control input to the generator set to reduce the engine speed to the second speed; and

operating the power generation system in the second state.

15. The controller of claim 10, wherein the second state further comprises:

charging the electrical storage device through the generator set.

16. The controller of claim 10, wherein the controller is further configured to operate the power generation system in an alternative mode when an engine of the generator set is off, the alternative mode comprising:

determining an increased load demand or a decreased load demand; and

providing, by the second inverter, power from the external power source to the electrical storage device in response to determining a reduced load demand.

17. The controller of claim 16, wherein the generator set further comprises an alternator, and wherein the controller is further configured to, in response to determining an increased load demand:

supplying power from the electrical storage device to the load through the second inverter;

supplying power from the electrical storage device to the alternator through the first inverter;

providing a control input to the generator set to start the engine; and

connecting the generator set to the load through the switching device in response to determining that an engine of the generator set is operating at the first speed.

18. A method of operating an electrical power generation system comprising a controller, a generator set, a switching device, a first inverter, a second inverter, and an electrical storage device, the method comprising:

the controller determining whether an external power source is supplying power to the load;

in response to determining that the external power source is not supplying power to the load, the controller operates the power generation system in a first state in which:

an engine of the generator set operates at a first speed;

closing the switching device to connect the generator set to the load; and

the generator set charging the electrical storage device through at least one of the first inverter or the second inverter; and

in response to determining that the external power source is supplying power to the load, the controller operates the power generation system in a second state in which:

the engine is operated at a second speed lower than the first speed;

-opening the switching means; and

the genset supplies power to the load through the first inverter and the second inverter, wherein the first inverter functions as a rectifier.

19. The method of claim 18, wherein the controller is further configured to:

detecting whether the external power source is added to supply power to the load; and

in response to detecting the addition of an external power source, switching the power generation system from the first state to the second state by:

reducing a speed of an engine of the generator set from the first speed to the second speed;

using the first inverter as a rectifier; and

the switching device is opened.

20. The method of claim 18, wherein the controller is further configured to:

detecting to remove the external power source; and

in response to detecting that the external power source has been removed, switching the power generation system from the second state to the first state by:

configuring the electrical storage device to supply power to the load;

increasing a speed of an engine of the generator set from the second speed to the first speed; and

closing the switching device.

Technical Field

The present invention generally relates to generator sets.

Background

A generator set ("genset") may be used in conjunction with a renewable energy source (e.g., solar energy, wind energy, etc.). With this supplement of an external energy source (i.e., an external power source), the output power required by the genset to meet the load demand may be below rated, and the engine of the genset may not be operating inefficiently at a fixed speed. Operating the variable speed genset at a variable speed based on the power demand of the load may improve genset efficiency and reduce engine fuel consumption. When the load is light, the engine of the variable speed genset can be operated at a lower speed. When the load is heavy, the engine speed will increase accordingly. Many fixed speed and variable speed gensets operate inefficiently.

Disclosure of Invention

In one aspect, the inventive concepts disclosed herein relate to a power generation system that includes a genset, a switching device, an electrical storage device, a first inverter, a second inverter, and a controller. The generator set includes an engine. A switching device is configured to connect the genset to a load, the switching device having an input terminal electrically connected to the genset and an output terminal electrically connected to the load. The first inverter is connected between the input terminal of the switching device and the electrical storage device. The second inverter is connected between the output terminal of the switching device and the electrical storage device. The controller may be communicatively coupled to the genset, the switching device, the first inverter, and the second inverter. The controller is configured to determine whether the external power source is supplying power to the load. The controller is further configured to operate in a first state in response to determining that the external power source is not supplying power to the load, wherein in the first state, an engine of the genset is operating at a first speed, the switching device is closed to connect the genset to the load, and the genset charges the electrical storage device through at least one of the first inverter or the second inverter. The controller is further configured to operate the power generation system in a second state in response to determining that the external power source is supplying power to the load, wherein in the second state the engine is operating at a second speed that is lower than the first speed, the switching device is open, and the genset is supplying power to the load through the first inverter and the second inverter, wherein the first inverter operates as a rectifier.

In some embodiments, the controller is further configured to detect that an external power source is being added to supply power to the load, and in response to detecting that the external power source is being added, switch the power generation system from the first state to the second state by: the method includes reducing a speed of an engine of the genset from a first speed to a second speed, using the first inverter as a rectifier, and opening the switching device.

In some embodiments, the controller is further configured to detect that the external power source is being removed, and in response to detecting that the external power source is being removed, switch the power generation system from the second state to the first state to supply power to the load by configuring the electrical storage device, increase the speed of the engine of the genset from the second speed to the first speed, and close the switching device.

In some embodiments, the power generation system further includes a sensor communicatively coupled to the controller, the sensor configured to measure a voltage level at the output terminal of the switching device, the measured voltage level providing an indication that the external power source is supplying power to the load. In some embodiments, the second state further comprises charging the electrical storage device with the genset power generation system.

In some embodiments, in response to determining that the external power source does not meet the load demand, the controller is configured to switch from the second state to the first state by providing a control input to the genset to increase the engine speed to a first speed, the load being powered from the genset through the first inverter and the second inverter, wherein the first inverter is configured to function as a rectifier and the second inverter is configured to synchronize power to the load. In response to determining that an engine of the genset is operating at a first speed, the controller is configured to connect the genset to a load through the switching device and operate the power generation system in a first state.

In some embodiments, in response to determining that the external power source is meeting the load demand, the controller is configured to provide a control input to the genset to reduce the engine speed to a second speed by disconnecting the genset from the load using the switching device to switch from the first state to the second state and operate the power generation system in the second state.

In some embodiments, the controller is further configured to operate the power generation system in an alternative mode when an engine of the genset is off, the alternative mode including determining an increased load demand or a decreased load demand based on the measured voltage level received from the sensor, and in response to determining the decreased load demand, supplying power from the external power source to the electrical storage device through the second inverter.

In some embodiments of the alternative mode, in response to determining the increased load demand, the genset is configured to supply power from the electrical storage device to the load through the second inverter, supply power from the electrical storage device to the alternator through the first inverter, supply a genset control input to start the engine, and connect the genset to the load through the switching device in response to determining that the engine of the genset is operating at the first speed.

In another aspect, the inventive concepts disclosed herein relate to a controller for a power generation system. The controller is communicatively coupled to the genset, the switching device, the first inverter, and the second inverter. The controller is configured to determine whether the external power source is supplying power to the load. The controller is further configured to, in response to determining that the external power source is not supplying power to the load, operate the genset in a first state in which an engine of the genset is operating at a first speed, close the switching device to connect the genset to the load, and charge the electrical storage device with the at least one genset of the first inverter or the second inverter. The controller is further configured to operate the power generation system in a second state in which the engine is operating at a second speed that is lower than the first speed, the switching device is open, and the genset supplies power to the load through the first inverter and the second inverter, wherein the first inverter functions as a rectifier, in response to determining that the external power source is supplying power to the load.

In some embodiments, the controller is further configured to detect that an external power source is being added to supply power to the load, and in response to detecting that the external power source is being added, switch the power generation system from the first state to the second state by: the method includes reducing a speed of an engine of the genset from a first speed to a second speed, using the first inverter as a rectifier, and opening the switching device.

In some embodiments, the controller is further configured to detect that the external power source is being removed, and in response to detecting that the external power source is being removed, switch the power generation system from the second state to the first state to supply power to the load by configuring the electrical storage device, increase the speed of the engine of the genset from the second speed to the first speed, and close the switching device. In some embodiments, the second state further comprises charging the electrical storage device with the genset power generation system.

In some embodiments, in response to determining that the external power source does not meet the load demand, the controller is configured to switch from the second state to the first state by providing a control input to the genset to increase the engine speed to a first speed, the load being powered from the genset through the first inverter and the second inverter, wherein the first inverter is configured to function as a rectifier and the second inverter is configured to synchronize power to the load. In response to determining that an engine of the genset is operating at a first speed, the controller is configured to connect the genset to a load through the switching device and operate the power generation system in a first state.

In some embodiments, in response to determining that the external power source is meeting the load demand, the controller is configured to provide a control input to the genset to reduce the engine speed to a second speed by disconnecting the genset from the load using the switching device to switch from the first state to the second state and operate the power generation system in the second state.

In some embodiments, the controller is further configured to operate the power generation system in an alternative mode when an engine of the genset is off, the alternative mode including determining an increased load demand or a decreased load demand based on the measured voltage level received from the sensor, and in response to determining the decreased load demand, supplying power from the external power source to the electrical storage device through the second inverter.

In some embodiments of the alternative mode, in response to determining the increased load demand, the genset is configured to supply power from the electrical storage device to the load through the second inverter, supply power from the electrical storage device to the alternator through the first inverter, supply a genset control input to start the engine, and connect the genset to the load through the switching device in response to determining that the engine of the genset is operating at the first speed.

In another aspect, the inventive concepts disclosed herein relate to a method of operating a power generation system that includes a controller, a genset, a switching device, a first inverter, a second inverter, and an electrical storage device. The method includes determining whether an external power source is supplying power to a load. The method further comprises the following steps: in response to determining that the external power source is not supplying power to the load, operating the power generation system in a first state in which an engine of the genset is operating at a first speed, closing the switching device to connect the genset to the load, and charging the electrical storage device with at least one of the first inverter or the second inverter. The method further comprises the following steps: in response to determining that the external power source is supplying power to the load, operating the power generation system in a second state in which the engine is operating at a second speed that is lower than the first speed, the switching device is open, and the genset supplies power to the load through the first inverter and the second inverter, wherein the first inverter functions as a rectifier.

In some embodiments, the method further comprises: the method further includes detecting that an external power source is being added to supply power to the load, and in response to detecting that the external power source is being added, switching the power generation system from a first state to a second state by reducing a speed of an engine of the genset from a first speed to a second speed, using the first inverter as a rectifier, and opening the switching device.

In some embodiments, the method further includes detecting that the external power source is being removed, and in response to detecting that the external power source is being removed, switching the power generation system from the second state to the first state, increasing the speed of the engine of the genset from the second speed to the first speed, and closing the switching device by configuring the electrical storage device to supply power to the load.

These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.

Drawings

FIG. 1 is a block diagram of a power generation system according to an example embodiment.

FIG. 2 is a configuration of the power generation system of FIG. 1 with the genset in an off state, according to an example embodiment.

FIG. 3 is another configuration of the power generation system of FIG. 1 in which a generator set is being started, according to an example embodiment.

FIG. 4 is another configuration of the power generation system of FIG. 1 in which the generator set is operating normally and there is no external power source, according to an example embodiment.

FIG. 5 is another configuration of the power generation system of FIG. 1 in which an external power source is present, according to an example embodiment.

FIG. 6 is another configuration of the power generation system of FIG. 1 in which an external power source is present and the genset is in an idle state, according to an example embodiment.

FIG. 7 is another configuration of the power generation system of FIG. 1, in which there is no external power source, according to an example embodiment.

FIG. 7A is a configuration of the power generation system of FIG. 1 with the generator set in an alternate mode of operation, according to an example embodiment.

FIG. 7B is another configuration of the power generation system of FIG. 1 in which the generator set is in an alternate mode of operation, according to an example embodiment.

FIG. 7C is another configuration of the power generation system of FIG. 1 in which the generator set is in an alternate mode of operation, according to an example embodiment.

FIG. 8 is another configuration of the power generation system of FIG. 1 in which the generator set is returned to normal operation, according to an example embodiment.

FIG. 9 is a flow chart of a method for controlling the power generation system of FIG. 1, according to an example embodiment.

Detailed Description

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the disclosure as illustrated therein are contemplated as would normally occur to one skilled in the art to which the disclosure relates.

Referring generally to the drawings, various embodiments disclosed herein relate to systems and methods for controlling a power generation system operating in conjunction with an external power source to supply power to a load. For example, the external power source may include a renewable energy source, such as a solar energy source, a wind energy source, or the like. External power sources such as the aforementioned renewable energy sources may not always be available. The power generation system includes a generator set ("genset") and power electronics connected to each other. The generator set may be a fixed speed generator set. The power electronics include a power storage device (e.g., battery, super capacitor) and two inverters. When the external power supply does not supply power, the generator set can be controlled to work under normal operation to supply power to the load. In some embodiments, the two bidirectional inverters may operate to charge excess energy not needed by the load in the power storage device, and may additionally act as an active filter for the power generation system. The two inverters and the power storage device may help maintain a fixed output voltage and frequency when a transient load is applied. When the external power source is increased to meet the maximum power demand of the load, the genset can be controlled to operate at a fixed speed reduction, variable speed reduction, idle state, or shut down to save fuel and extend engine life. One inverter acts as a rectifier to convert Alternating Current (AC) from the generator set to Direct Current (DC), and the other inverter converts the DC from the first inverter or energy storage device to AC to meet the voltage and frequency requirements of the load. The excess alternating current generated by the generator set and converted to direct current by the first inverter may be used to charge the energy storage device. When the external energy source (i.e., external power source) is suddenly removed, the power storage device may provide direct current that is converted by one of the inverters into alternating current of appropriate voltage and frequency. The genset may be controlled (e.g., temporarily) to accelerate and supply power to the load by directly providing synchronous ac power by closing the switch or indirectly providing synchronous ac power by the first inverter and the second inverter while the switch remains in the open state.

Referring now to FIG. 1, a block diagram of a power generation system 100 connected to a power grid 102 is shown, according to an example embodiment. Power system 100 is shown to include genset 110, power electronics 120, controller 130, sensors 132, and switchgear 140. The power generation system 100 may be implemented on a vehicle (e.g., a motor home), a stationary facility, an industrial work machine, and so forth. The power grid 102 is shown to include a plurality of loads 150 and an external power source 160. The load 150 may include various types of electrical devices, such as one or more air conditioners, lighting devices, kitchen appliances, entertainment devices, and/or other different devices. The power demand of the load 150 may vary over time. For example, the power demand of the load 150 may be low when most of the electronics are off, or the power demand of the load 150 may be high when most of the electronics are on. An external power source 160 is connected to the power grid 102 to supply power to the load 150 through an inverter 162. The external power source 160 may include a renewable energy source, such as a photovoltaic energy source, wind energy, or the like. The external power source 160 may not always be used to power the load 150.

In the illustrated embodiment, the generator set 110 includes an engine 112 as a prime mover and an alternator 114 as an electric machine coupled to and driven by the engine 112. The engine 112 may include an internal combustion engine or any other suitable prime mover that consumes fuel (e.g., gasoline, diesel fuel, natural gas, etc.) and provides mechanical energy (e.g., rotational torque) during operation to drive the alternator 114, such as by a crankshaft. The alternator 114 is operatively coupled to the engine 112 and may be powered by the engine 112 to generate electrical power for operating, for example, a load 150. Alternator 114 may include, but is not limited to, a synchronous generator, a permanent magnet machine, an induction machine, a switched reluctance machine, or any other suitable motor or generator capable of producing an electrical output in response to a mechanical input, or a mechanical output in response to an electrical input. In some embodiments, the alternator 114 may be a starter/alternator that integrates the functionality of a starter motor and an alternator used in an engine system. The genset 110 can operate at a fixed speed to generate power at the grid frequency. In some embodiments, the rated speed of the engine 112 and alternator 114 is 1500rpm for 50Hz power grid applications, or 1800 (or 1200) rpm for 60Hz power grid applications.

The power electronics 120 include a power storage device 122, a first inverter 124, and a second inverter 126. The power storage device 122 may include a battery (e.g., lithium ion battery, nickel metal hydride battery, lead acid battery), a super capacitor, a flywheel, or any suitable power storage device that may store electrical energy and release the stored energy for use. In some embodiments, the power storage device 122 may include multiple devices, such as a battery pack including multiple batteries. The power storage device 122 may be configured to supply power to supplement power generated by the genset 110 (e.g., during high demand) and to store excess power generated by the genset 110 (e.g., during low demand). The first inverter 124 and the second inverter 126 may each be configured to function as an inverter that converts direct current to alternating current or a rectifier that converts alternating current to direct current. In some embodiments, the first inverter 124 and/or the second inverter 126 may include an H-bridge configured with four transistors (e.g., Insulated Gate Bipolar Transistors (IGBTs), Field Effect Transistors (FETs), gate thyristors, Silicon Controlled Rectifiers (SCRs)) controlled by a Pulse Width Modulation (PWM) signal. The PWM control signals may selectively and individually drive each gate/switch of the inverter. It is noted that in some embodiments, the first inverter 124 may be replaced by a rectifier and the second inverter 126 may be replaced by a single direction/output only inverter.

The switching device 140 connects the power generation system 100 to the power grid 102. In some embodiments, the switching device 140 may include an electrically controlled output contactor including a first terminal 142 (also referred to as an input terminal) and a second terminal 144 (also referred to as an output terminal). The switching device 140 may be in an open state, wherein the input terminal 142 is disconnected from the output terminal 144, or in a closed state, wherein the input terminal 142 is connected to the output terminal 144. Genset 110 is connected to input terminal 142. The power grid 102 is connected to the output terminals 144. The first inverter 124 is connected between the input terminal 142 and the power storage device 122. The second inverter 126 is connected between the output terminal 144 and the power storage device 122.

The sensor 132 is connected to an output terminal 144 of the switching device 140 and is configured to monitor a state of the power grid 102. In some embodiments, the sensor 132 comprises a voltage sensor configured to sense the voltage at the power grid 102, which may reflect the presence or absence of the external power source 160, as well as any changes in the power demand of the load 150. For example, when there is a step load or a sudden decrease in power provided by the external power source 160, the sensor 132 may sense a voltage drop at the power grid 102. The sensor 132 may sense a voltage surge at the power grid 102 when the load decreases or the power provided by the external power source 160 suddenly increases. In some embodiments, the sensor 132 may include other types of sensors, such as a current sensor or other type of load sensor.

Controller 130 may be communicatively coupled to genset 110, power electronics 120, switching device 140, and sensors 132, and configured to control operation of genset 110, power electronics 120, and switching device 140 based on information received from sensors 132. Communication between components may be through any number of wired or wireless connections. For example, the wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. In contrast, the wireless connection may include the Internet, Wi-Fi, cellular, radio, and the like. In one embodiment, the CAN bus provides for the exchange of signals, information, and/or data. The CAN bus includes any number of wired and wireless connections.

Controller 130 may be implemented as a general purpose processor, an Application Specific Integrated Circuit (ASIC), one or more Field Programmable Gate Arrays (FPGAs), a Digital Signal Processor (DSP), a set of processing components, or other suitable device electronic processing components. In some embodiments, the controller 130 may include one or more memory devices (e.g., non-volatile random access memory (NVRAM), Random Access Memory (RAM), Read Only Memory (ROM), flash memory, hard disk memory, etc.) that store data and/or computer code to facilitate various processes (processes) performed by the controller 130. The one or more storage devices may be or include tangible, non-transitory, volatile or non-volatile memory, database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. In some embodiments, the controller 130 may be integrated as part of an engine controller. In other embodiments, the controller 130 may be a stand-alone device.

The controller 130 may control the speed of the motor 112 of the genset 110, the state of the switching device 140 (i.e., open state or closed state), and the operating state of the first and second inverters 124, 126 (i.e., functioning as inverters or rectifiers). The control process is described in more detail below with reference to fig. 2-8. The components shown in fig. 2-8 correspond substantially to the same components shown in fig. 1, except that the controller 130 and the sensor 132 are omitted in fig. 2-8, to more clearly illustrate the process.

Referring to fig. 2, a configuration 200 of the power generation system 100 is shown, wherein in this configuration the genset 110 is off. In configuration 200, genset 110 is off, i.e., the speed of engine 112 is zero. Because genset 110 is not outputting power, switching device 140 (e.g., output contactor) is placed in an open state.

Referring to fig. 3, a configuration 300 of the power generation system 100 is shown in which the genset 110 is starting up. In configuration 300, the speed of engine 112 is increasing, but has not yet reached a rated speed (e.g., in some embodiments, the rated speed is 1500rpm for a 50Hz power grid application, or 1800 (or 1200) rpm for a 60Hz power grid application). Thus, the voltage and/or frequency of the alternating current output from the genset 110 is not synchronized with the power grid 102. Controller 130 places switchgear 140 in an open state such that genset 110 is not connected to power grid 102. The controller 130 uses the first inverter 124 as a charger (i.e., rectifier) that converts the alternating current output by the genset 110 into direct current and charges the power storage device 122 with the direct current. In some embodiments, the controller 130 may monitor the charge state of the power storage device 122. In response to determining a low charge condition (e.g., a charge amount below a threshold charge level), controller 130 may control first inverter 124 to receive power from genset 110. Power may also be sent to the power grid 102 through the second inverter 126 from direct current provided through the power storage device 122 or the first inverter 124.

Referring to fig. 4, a configuration 400 of the power generation system 100 is shown in which the genset 110 is operating normally and there is no external power source 160 or, alternatively, in which the genset 110 is connected in parallel with the power grid 102 and another external power source is provided thereon. In configuration 400, engine 112 is operating at a rated speed (e.g., in some embodiments, 1500rpm for 50Hz power grid applications, or 1800 (or 1200) rpm for 60Hz power grid applications). Controller 130 controls the voltage, frequency, and/or phase of the alternating current output from genset 110 to synchronize with the voltage, frequency, and/or phase of power grid 102 and closes contacts of switching device 140 to cause genset 110 to supply power to power grid 102.

Controller 130 may determine that a transient occurs during operation based on, for example, information received from sensor 132. As described above, when a large load is added, the sensor 132 may sense the voltage drop; when a large load is removed, the sensor 132 may sense a voltage surge. Any suitable method may be used to detect or determine whether a large load has been added or removed. In some embodiments, the controller 130 may be configured to use various thresholds and/or percentages based on the power output of the genset 110 in normal operation, the steady state power provided by the external power source 160, the relative load size, the capacity of the power storage device 122, and the like. For example, the power storage device 122 may have a rated capacity sized to allow a particular time transient (e.g., 10 second, 30 second, 1 minute transient), and in this example, the threshold may be based on a rated capacity size value.

In response to detecting the transient, the controller 130 may control the first inverter 124 and/or the second inverter 126 to charge or discharge the power storage device 122 to help absorb the transient. For example, when a large load is added, the controller 130 may operate the first inverter 124 and/or the second inverter 126 to convert the direct current drawn from the power storage device 122 to alternating current and supply the alternating current to the load 150 to supplement the alternating current output from the generator set 110. When a large load is removed, the controller 130 may operate the first inverter 124 and/or the second inverter 126 to convert excess ac power generated by the genset 110 to dc power and charge the power storage device 122 with the dc power. In some embodiments, the first inverter 124 and the second inverter 126 may also function as active filters for reactive power injection or cancellation, and apply Total Harmonic Distortion (THD) correction to the output voltage through the power generation system 100.

Referring to fig. 5, a configuration 500 of the power generation system 100 is shown in which an external power source 160 is added to the power grid 102 when the genset 110 is in normal operation. In some embodiments, when the external power source 160 begins to supply power to the power grid 102, the sensor 132 may sense the presence of the external power source 160 by detecting a voltage at the power grid 102. In configuration 500, genset 110 may supply power to load 150 directly via synchronous parallel power generation by coupling with switch 140 or indirectly to load 150 through first inverter 124 and second inverter 126. In particular, in response to detecting the presence of the external power source 160, the controller 130 operates the first inverter 124 (as a rectifier), converting the ac power output from the genset 110 to dc power to charge the power storage device 122 and provide the dc power to the second inverter 126. It may also operate a second inverter 126 to convert direct current to alternating current. The ac output from the second inverter 126 is synchronized in amplitude, frequency, and/or phase with the ac at the power grid 102.

In configuration 500, genset 110 or external power source 160 may charge power storage device 112 via first inverter 124 or second inverter 126. Inrush power may also be provided from the power storage device 112 to the suddenly increased load 150 (load "step") via the first inverter 124 or the second inverter 126, and the need for redundant "run-by-run" functionality in the genset 110 is reduced or eliminated, and allows time for the genset 110 to react to the change. Excess energy from the sudden load demand drop may also be absorbed by the power storage device 112 via the first inverter 124 or the second inverter 126 and allow time for the genset 110 to react to the change. If a large load is known to be imminent, such as a motor start, the genset 110 may be "pre-loaded" with the power storage device 112 temporarily absorbing the load and excess energy through the first inverter 124 or the second inverter 126. Loads that exceed the rated output or damage profile of the genset 110 may also be temporarily accommodated by providing energy from the power storage device 112 via the first inverter 124 or the second inverter 126. Additionally, when coupled synchronously (directly via switch 140) or asynchronously (indirectly via inverters 124, 126), the change in response of genset 110 to the load may be allowed to occur slowly to allow the engine of genset 110 to respond gradually to the load change, and thus genset 110 may conserve fuel, avoid excessive emissions, and reduce noise and/or human perception of the load change. In some embodiments, the first inverter 124 and the second inverter 126 may also function as active filters for reactive power injection or cancellation, and apply Total Harmonic Distortion (THD) correction to the output voltage through the power generation system 100.

Referring to fig. 6, a configuration 600 of the power generation system 100 is shown in which the external power source 160 covers most of the power demand of the load 150 (e.g., > 80%) and the genset 110 is operating at idle or, alternatively, the external power source 160 covers sufficient power demand of the load 150 and the genset's engine 112 is inefficient. In response to determining that the external power source 160 covers a majority of the power demand of the load 150, the controller 130 may instruct the engine 112 to be turned off, or the speed of the engine 112 to be reduced to a fixed low, variable, or idle speed. These speeds may be significantly lower than the rated speed of the engine 112. For example, the idle speed may be as low as 500rpm, while the nominal speed is 1200, 1500 or 1800 rpm. The direct ac output of the genset 110 does not match the power grid application in voltage and/or frequency. Controller 130 places switching device 140 in an open state and controls genset 110 to supply power to load 150 through first inverter 124 and second inverter 126. Specifically, the controller 130 operates the first inverter 124 (acting as a rectifier) to convert the alternating current output from the genset 110 to direct current, and operates the second inverter 126 to convert the direct current to alternating current. The ac output from the second inverter 126 is synchronized in amplitude, frequency, and/or phase with the ac at the power grid 102. In other words, in configuration 600, first inverter 124 provides direct current and second inverter 126 provides an alternating output voltage at a fixed frequency (e.g., 50Hz or 60Hz) for the desired THD. When genset 110 is operating at a low fixed, variable, or idle speed, fuel may be saved and engine life may be extended.

In some embodiments, when genset 110 is operating at a low fixed speed, variable speed, or idle speed, the direct ac output may be sufficient to meet the demand of load 150 and charge power storage device 122. Controller 130 may place switchgear 140 in an open state such that genset 110 is not connected to power grid 102. The controller 130 operates the first inverter 124 to convert the alternating current output from the genset 110 to direct current, and charges the device 122 with excess direct current. The second inverter 126 converts the remaining direct current output from the power storage device 122 and/or the first inverter 124 into alternating current to supply the alternating current to the load 150. The ac output from the second inverter 126 is synchronized with the ac at the power grid 102.

Referring to fig. 7, a configuration 700 of the power generation system 100 is shown in which power provided by the external power source 160 is reduced or eliminated from the power grid 102 when the genset 110 is operating at a low fixed speed, variable speed, idle speed, or off state. In some embodiments, when the external power source 160 suddenly disappears, the sensor 132 may sense a decrease or disappearance of the power provided by the external power source 160 by detecting a voltage (e.g., voltage drop) at the power grid 102. The generated power from running genset 110 at the reduced speed may not meet the power demand of load 150. The controller 130 operates the second inverter 126 to draw power from the power storage device 122 to supply the load 150. Specifically, the second inverter 126 converts the direct current output from the power storage device 122 into alternating current, and supplies the alternating current power to the load 150. The ac output from the second inverter 126 is synchronized in amplitude, frequency, and/or phase with the ac at the power grid 102.

At the same time, the controller 130 instructs the engine 112 to start or increase from a reduced or idle speed. The direct ac output from genset 110 does not meet the power grid requirements until the rated speed is reached (e.g., 1500rpm for 50Hz power grid applications, or 1800 (or 1200) rpm for 60Hz power grid applications in some embodiments). The controller 130 maintains the contacts of the switching device 140 in an open state during acceleration and controls the genset 110 to supply power to the load 150 through the first inverter 124 and the second inverter 126. Specifically, the controller 130 operates the first inverter 124 (acting as a rectifier) to convert the alternating current output from the genset 110 to direct current, and operates the second inverter 126 to convert the direct current to alternating current. The ac electrical power output from the second inverter 126 (i.e., the combined ac power output from the power storage device 122 and the genset 110) is synchronized in amplitude, frequency, and/or phase with the ac voltage at the power grid 102.

In some embodiments, as shown in fig. 7A-7C, controller 130 may be configured to operate in an alternate operating mode to facilitate rapid starting and synchronization of genset 110. When the genset 110 is not operating (e.g., the engine 112 is off), an alternative operating mode may be used. In some embodiments of the alternative mode of operation, the controller 130 opens the contacts of the switching device 140. In some embodiments of alternative modes of operation, the polarity of the first inverter 124 and/or the second inverter 126 may be switched or otherwise configured to provide direct current and/or alternating current to the external power source 160 and direct current and/or alternating current from the external power source 160. For example, each of the first inverter 124 and/or the second inverter 126 may include two or more inverters (e.g., branch circuits) to enable bidirectional flow of direct current and/or alternating current.

Referring to fig. 7A, configuration 710 illustrates one exemplary configuration of the alternative mode. In configuration 710, external power source 160 may provide power to load 150 and/or power storage device 122. For example, during a high demand transient period, the external power source 160 may preferentially provide ac power to the load 150. Conversely, during periods of low demand, the external power source 160 may preferentially supply power to the power storage device 122 due to excess alternating current generated by the external power source 160.

Referring to fig. 7B, configuration 720 illustrates another example configuration of an alternative mode. In configuration 720, power storage device 122 may be used to reduce the time to restart genset 110 and synchronize genset 110, thereby allowing controller 130 to quickly close the contacts of switching device 140. In configuration 720, the load 150 is powered from the external energy device 122, but some power from the power storage device 122 is directed through the first inverter 124 into the alternator 114 to operate the alternator as a motor to assist in genset 110 start-up and grid resynchronization.

Referring to fig. 7C, configuration 730 shows the engine 112 operating at a rated speed and the voltage, frequency, and/or phase of the alternating current output from the genset 110 synchronized with the voltage, frequency, and/or phase of the power grid 102. In configuration 730, controller 130 closes contacts of switching device 140 such that genset 110 supplies power to load 150. In some embodiments of configuration 730, genset 110 may provide power to power storage device 122 as described above.

Referring to fig. 8, a configuration 800 of the power generation system 100 is shown in which the genset 110 is returned to normal synchronous operation. In configuration 800, engine 112 is operating at a rated speed (e.g., in some embodiments, 1500rpm for 50Hz power grid applications, or 1200 or 1800rpm for 60Hz power grid applications). Controller 130 controls the voltage, frequency, and/or phase of the alternating current output from genset 110 to synchronize with the voltage, frequency, and/or phase of power grid 102 and places switching device 140 in a closed state such that genset 110 is providing power to power grid 102. Controller 130 may further operate first inverter 124 to charge power storage device 122 to restore any stored power used. That is, the first inverter 124 functions as a rectifier that converts the alternating current output from the generator set 110 into direct current and charges the power storage device 122 with the direct current.

Referring now to FIG. 9, a flowchart of a method 900 for controlling the power generation system 100 is shown, according to an example embodiment. The method 900 may be performed by the controller 130 of fig. 1. The power generation system 100 includes: a genset 110 and a switching device 140, the genset 110 including an engine 112, the switching device 140 including an input terminal 142 connected to the genset 110 and an output terminal 144 configured to be connected to a load 150. The power generation system 100 also includes an electrical storage device 122, a first inverter 124 connected between the input terminal 142 and the electrical storage device 122, and a second inverter connected between the output terminal 144 and the electrical storage device 122. The controller 130 may be communicatively coupled to the genset 110, the switching device 140, the first inverter 124, the second inverter 126, and/or any other device or system to facilitate implementing the method 900 (e.g., the method of the power generation system 100).

At 902, the controller 130 determines whether the external power source 160 is supplying power to the load 150. The controller 130 may determine whether there is power provided by the external power source 160 based on information received from the sensor 132. In some embodiments, the sensor 132 comprises a voltage sensor configured to sense a voltage at the power grid 102, which may reflect the presence or absence of the external power source 160. For example, when the power provided by the external power source 160 suddenly decreases, the sensor 132 may sense a voltage drop at the power grid 102. When the power provided by the external power source 160 suddenly increases, the sensor 132 may sense a voltage surge at the power grid 102. In some embodiments, the sensors 132 may include other types of sensors, such as current sensors, load sensors, and the like.

In response to determining that the external power source 160 is not supplying power to the load 150 (902), the controller 130 operates the power generation system in a first state in which the engine 112 of the genset 110 is operating at a first speed (904), the switching device 140 is closed to connect the genset 110 to the load 150(906), and the genset 110 charges the electrical storage device 122 through at least one of the first inverter 124 or the second inverter 126 (908). In some embodiments, the first speed is a rated speed, for example 1500rpm for 50Hz power grid applications, or 1800 (or 1200) rpm for 60Hz power grid applications.

In some embodiments, in the first state, the controller 130 may determine that a transient occurs and control the first inverter 124 and/or the second inverter 126 to charge or discharge the power storage device 122 in response to detecting the transient. For example, when a large load is added, the controller 130 may operate the first inverter 124 and/or the second inverter 126 to convert the direct current drawn from the power storage device 122 to alternating current and supply the alternating current to the load 150 to supplement the alternating current output from the generator set 110. When a large load is removed, the controller 130 may operate the first inverter 124 and/or the second inverter 126 to convert excess ac power generated by the genset 110 to dc power and charge the power storage device 122 with the dc power.

In response to determining at 902 that the external power source is supplying power to the load, the controller 130 operates the power generation system 100 in a second state in which the engine 112 is operating at a second speed that is lower than the first speed (910), the switching device 140 is open (912), and the genset 110 supplies power to the load 150 through the first inverter 124 and the second inverter 126, wherein the first inverter 124 functions as a rectifier (914). The second speed may be a lower fixed speed, a lower variable speed or an idle speed of the engine, which is significantly lower than the nominal speed. Thus, the direct ac output from the genset 110 is not compatible with power grid applications. Controller 130 places switching device 140 in an open state and controls genset 110 to supply power to load 150 through first inverter 124 and second inverter 126. Specifically, the controller 130 operates the first inverter 124 (acting as a rectifier) to convert the alternating current output from the genset 110 to direct current, and operates the second inverter 126 to convert the direct current to alternating current. The ac output from the second inverter 126 is synchronized in amplitude, frequency, and/or phase with the ac at the power grid 102.

In some embodiments, the controller 130 may detect that an external power source 160 is being added to power the load 160 and, in response to detecting its presence, switch the power generation system 100 from the first state to the second state. At the time of switching, the controller 130 reduces the speed of the engine from the first speed to the second speed, the first inverter 124 functions as a rectifier, and the switching device 140 is turned off.

In some embodiments, the controller 130 may detect a decrease or loss of power provided by the external power source 160 and switch the power generation system 100 from the second state to the first state in response to the detected decrease or loss. At the time of the switch, the controller 130 provides power from the electrical storage device 122 to the load 150 through the second inverter 126, increases the speed of the engine from the second speed to the first speed, and closes the switching device.

It should be understood that elements claimed herein should not be construed in accordance with the definition of 35u.s.c.112(f), unless the phrase "for.

For the purposes of the present invention, the term "coupled" means that two members are directly or indirectly joined or connected to each other. Such connections may be fixed or movable in nature. For example, a driveshaft of an engine is "coupled" to a representation of a transmission, which represents a movable coupling. Such joining may be achieved with two members or with two members and any additional intermediate members. For example, circuit a being communicatively "coupled" to circuit B may mean that circuit a is in direct communication with circuit B (i.e., without intermediaries) or in indirect communication with circuit B (e.g., through one or more intermediaries).

It should be understood that the controller 130 may include any number of circuits for performing the functions described herein. Further, it should be understood that the controller 150 may further control other activities beyond the scope of the present disclosure.

The controller 130 may be implemented in a machine-readable medium for execution by various types of processors. For example, circuitry of the identified executable code may comprise one or more physical or logical blocks of computer instructions, which may be organized as an object, procedure, or function. Nevertheless, the executables of an identified circuit need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the circuit and achieve the stated purpose for the circuit. Indeed, the circuitry of the computer readable program code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within circuitry, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

Although the term "processor" is briefly defined above, it should be understood that the terms "processor" and "processing circuitry" should be interpreted broadly. In this regard and as described above, a "processor" may be implemented as one or more general-purpose processors, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), Digital Signal Processors (DSPs), or other suitable electronic data processing components configured to execute instructions provided by a memory. The one or more processors may take the form of single-core processors, multi-core processors (e.g., dual-core processors, tri-core processors, quad-core processors, etc.), microprocessors, and the like. In some embodiments, one or more of the processors may be external to the apparatus, e.g., one or more of the processors may be a remote processor (e.g., a cloud-based processor). Preferably or additionally, the one or more processors may be internal and/or local to the apparatus. In this regard, a given circuit or component thereof may be disposed locally (e.g., as part of a local server, local computing system, etc.) or remotely (e.g., as part of a remote server, such as a cloud-based server). To this end, a "circuit" as described herein may include components distributed over one or more locations.

It should be noted that although the figures herein may show a particular order and composition of method steps, it should be understood that the order of the steps may differ from that depicted. For example, two or more steps may be performed simultaneously or partially simultaneously. Also, some method steps performed as separate steps may be combined, steps performed as combined steps may be separated into separate steps, the order of some processes may be reversed or otherwise varied, the nature or number of separate processes may be altered or varied. The order or sequence of any elements or devices may be varied or substituted according to alternative embodiments. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. These variations will depend on the machine-readable medium and hardware system chosen and on the choices of the designer. It is to be understood that all such variations are within the scope of the present invention.

The foregoing description of the embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from this disclosure. The embodiments were chosen and described in order to explain the principles of the disclosure and its practical application to enable one skilled in the art to utilize the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the embodiments without departing from the scope of the present disclosure as expressed in the appended claims.