CN110556817B - Direct-current micro-grid system and control method thereof - Google Patents
Direct-current micro-grid system and control method thereof Download PDFInfo
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- CN110556817B CN110556817B CN201910869100.0A CN201910869100A CN110556817B CN 110556817 B CN110556817 B CN 110556817B CN 201910869100 A CN201910869100 A CN 201910869100A CN 110556817 B CN110556817 B CN 110556817B
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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Abstract
The invention relates to a direct-current micro-grid system and a control method thereof. The direct-current micro-grid system comprises a control assembly, a direct-current bus, a clean energy assembly connected to the direct-current bus, an energy storage assembly and an alternating-current power generation assembly; the alternating current power generation assembly replaces a power grid to be connected into the direct current bus, stable voltage is provided for the direct current bus, dependence of the direct current micro-grid system on the power grid is eliminated, meanwhile, the energy storage assembly can also store electric quantity on the direct current bus, the control assembly can select one of the alternating current power generation assembly and the energy storage assembly to transmit electric energy to the direct current bus to maintain stability of voltage of the direct current bus, independent operation of the direct current micro-grid system is achieved, and power supply requirements of unstable power grid or even areas without the power grid are met.
Description
Technical Field
The invention relates to the technical field of micro-grids, in particular to a direct-current micro-grid system and a control method thereof.
Background
In order to achieve the aim of energy conservation and environmental protection, renewable energy is connected into a power grid in a large-scale grid-connected mode, but the characteristics of large scale and strong intermittence generate huge challenges for traditional power equipment, power grid structures and operation maintenance, and a micro-grid is produced in response to the impacts.
According to different networking modes, the microgrid is divided into a direct current microgrid and an alternating current microgrid, wherein the direct current microgrid generally comprises clean energy, an energy storage device, a direct current load, an alternating current power supply and the like, and all parts are merged into a direct current bus through converters in different forms. Compared with an alternating-current micro-grid, the direct-current micro-grid has the advantages of few current transformation links, high transformation efficiency, flexible control and convenience for distributed application, and can provide high-quality electric energy for individuals and enterprise users.
Because of the instability of clean energy, a power grid is required to provide stable voltage, but the power grid capacity of many underdeveloped regions in the world is small or unstable, even no power grid exists, the requirement cannot be met at all, and the construction and the operation of a direct current micro-power grid are hindered.
Disclosure of Invention
In view of this, the present invention aims to overcome the defects of the prior art, and provide a dc micro-grid system, which is independent of the power grid and can operate independently, so as to meet the power supply requirement of the unstable power grid or even the area without the power grid.
In order to achieve the purpose, the invention adopts the following technical scheme:
a direct current microgrid system comprising: the device comprises a control assembly, a direct current bus, a clean energy assembly connected to the direct current bus, an energy storage assembly and an alternating current power generation assembly;
the clean energy assembly is used for transmitting electric energy to the direct current bus;
the energy storage assembly is used for storing electric energy on the direct current bus;
the control assembly is connected with the energy storage assembly and the alternating current power generation assembly and is used for acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time and switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable;
the direct current bus is also used for connecting a direct current load to supply power.
Optionally, the state of the alternator component comprises a healthy state; the health state comprises a normal state and an abnormal state; the state of the energy storage assembly comprises an electric quantity state;
when one of the energy storage assembly and the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly, the control assembly is specifically configured to:
under the condition that the energy storage assembly transmits electric energy to the direct current bus, if the electric quantity of the energy storage assembly is lower than a first threshold value and the alternating current power generation assembly is in a normal state, the alternating current power generation assembly is switched and selected to transmit the electric energy to the direct current bus;
under the condition that the alternating current power generation assembly transmits the electric energy to the direct current bus, if the alternating current power generation assembly is in an abnormal state or the electric quantity of the energy storage assembly is higher than a second threshold value, the energy storage assembly is switched and selected to transmit the electric energy to the direct current bus.
Optionally, the state of the ac power generation assembly further includes a switch state; the switch state comprises a pre-opening state, an opening state, a pre-closing state and a closing state; the states of the energy storage assembly further comprise working states, and the working states comprise a voltage source mode and a current source mode;
when the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for adjusting the state of the alternating current power generation assembly to be a pre-starting state and controlling the energy storage assembly to output a first preset voltage; when the voltage of the direct current bus is the first preset voltage, adjusting the state of the alternating current power generation assembly to be a starting state; when the state of the alternating current power generation assembly is an opening state, the energy storage assembly is controlled to work in a current source mode to realize switching;
when the energy storage assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for adjusting the state of the alternating current generator to be a pre-closed state and controlling the energy storage assembly to output a second preset voltage; and when the alternating current power generation assembly is detected to be in a closed state, controlling the energy storage assembly to work in a voltage source mode, and continuously outputting the second preset voltage to realize switching.
Optionally, the first preset voltage is greater than the output voltage of the alternating current power generation assembly;
the second preset voltage is smaller than the output voltage of the alternating current power generation assembly.
Optionally, the control assembly includes: the information acquisition module and the decision response module are connected;
the information acquisition module is connected with the energy storage assembly and the alternating current power generation assembly and is used for acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time;
the decision response module is connected with the energy storage assembly and the alternating current power generation assembly and used for switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable.
Optionally, the ac power generation assembly includes: an alternator and a first AC/DC converter;
the alternating current generator is connected into the direct current bus through the first AC/DC converter and transmits electric energy to the direct current bus.
Optionally, the energy storage assembly includes: the energy storage module and the first DC/DC converter;
the energy storage module is connected to the direct current bus through the first DC/DC converter, stores electric energy on the direct current bus and transmits the electric energy to the direct current bus.
Optionally, the clean energy assembly comprises: an energy module; a second AC/DC converter and/or a second DC/DC converter;
the energy module is connected to the direct current bus through the second AC/DC converter and/or the second DC/DC converter, and electric energy is transmitted to the direct current bus.
A control method of a direct current micro-grid system is applied to the direct current micro-grid system, and comprises the following steps:
acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time;
and switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable.
Optionally, if the state of the ac power generation assembly includes a healthy state; the health state comprises a normal state and an abnormal state; the state of the energy storage assembly comprises an electric quantity state; the switching selection of one of the energy storage component and the alternating current power generation component to transmit electric energy to the direct current bus according to the obtained state of the energy storage component and the state of the alternating current power generation component comprises:
under the condition that the energy storage assembly transmits electric energy to the direct current bus, if the electric quantity of the energy storage assembly is lower than a first threshold value and the alternating current power generation assembly is in a normal state, the alternating current power generation assembly is switched and selected to transmit the electric energy to the direct current bus;
under the condition that the alternating current power generation assembly transmits the electric energy to the direct current bus, if the alternating current power generation assembly is in an abnormal state or the electric quantity of the energy storage assembly is higher than a second threshold value, the energy storage assembly is switched and selected to transmit the electric energy to the direct current bus.
The technical scheme provided by the application can comprise the following beneficial effects:
in the direct current microgrid system provided by the application, a control component, a direct current bus and an access are arranged, the clean energy component, the energy storage component and an alternating current power generation component are connected to the direct current bus, the clean energy component generates electric energy by utilizing natural resources such as solar energy and wind energy and transmits the electric energy to the direct current bus for load use, the residual electric quantity can be stored by the energy storage component, but the generated electric energy is unstable due to variability of the natural resources, the state of the energy storage component and the state of the alternating current power generation component are required to be acquired by the control component in real time, and according to the acquired state of the energy storage component and the state of the alternating current power generation component, one of the energy storage component and the alternating current power generation component transmits the electric energy to the direct current bus, so that the voltage on the direct current bus. The direct-current micro-grid system uses the alternating-current power generation assembly to replace a power grid to be connected into a direct-current bus, stable voltage is provided for the direct-current bus, dependence of the direct-current micro-grid system on the power grid can be eliminated, meanwhile, the energy storage assembly can also store electric quantity on the direct-current bus, the control assembly can select one of the direct-current bus to transmit electric energy to the direct-current bus through acquiring states of the alternating-current power generation assembly and the energy storage assembly so as to maintain stability of voltage of the direct-current bus, independent operation of the direct-current micro-grid system is achieved, and power supply requirements of unstable power.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a dc microgrid system according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a dc microgrid system according to an embodiment of the present invention.
Fig. 3 is a flowchart of a control method of a dc microgrid system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a dc microgrid system according to an embodiment of the present invention. As shown in fig. 1, the dc microgrid system provided in this embodiment includes: the device comprises a control assembly 11, a direct current bus 12, a clean energy assembly 13 connected to the direct current bus, an energy storage assembly 14 and an alternating current power generation assembly 15; wherein, the clean energy assembly 13 is used for transmitting electric energy to the direct current bus 12; the energy storage assembly 14 is used for storing electric energy on the direct current bus 12; the control component 11 is connected with the energy storage component 14 and the alternating current power generation component 15, and is used for acquiring the state of the energy storage component 14 and the state of the alternating current power generation component 15 in real time, and switching and selecting one of the energy storage component 14 and the alternating current power generation component 15 to transmit electric energy to the direct current bus 12 according to the acquired state of the energy storage component 14 and the state of the alternating current power generation component 15, so that the voltage on the direct current bus is kept stable; the dc bus 12 is also used to connect a dc load 16 for power supply.
The mode that the control assembly acquires the state of the energy storage assembly and the state of the alternating current power generation assembly can be used for sending a query instruction to the control assembly for querying in real time, and can also be used for actively uploading state information to the control assembly in real time for the energy storage assembly and the alternating current power generation assembly.
The alternating current power generation assembly replaces a power grid to be connected into the direct current bus, stable voltage is provided for the direct current bus, dependence of the direct current micro-grid system on the power grid is eliminated, meanwhile, the energy storage assembly can also store electric quantity on the direct current bus, the control assembly can select one of the alternating current power generation assembly and the energy storage assembly to transmit electric energy to the direct current bus to maintain stability of voltage of the direct current bus, independent operation of the direct current micro-grid system is achieved, and power supply requirements of unstable power grid or even areas without the power grid are met.
Optionally, the state of the alternator component comprises a healthy state; the health state comprises a normal state and an abnormal state; the state of the energy storage assembly comprises an electric quantity state;
according to the state of the energy storage assembly and the state of the alternating current power generation assembly, when one of the energy storage assembly and the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for:
under the condition that the energy storage assembly transmits electric energy to the direct current bus, if the electric quantity of the energy storage assembly is lower than a first threshold value and the alternating current power generation assembly is in a normal state, the alternating current power generation assembly is switched and selected to transmit the electric energy to the direct current bus;
under the condition that the alternating current power generation assembly transmits electric energy to the direct current bus, if the alternating current power generation assembly is in an abnormal state or the electric quantity of the energy storage assembly is higher than a second threshold value, the energy storage assembly is switched and selected to transmit the electric energy to the direct current bus.
In order to maintain the voltage on the dc bus stable, one of the ac power generation component and the energy storage component must immediately start to output stable voltage to the dc bus after the system is turned on, so when the system is turned on, an operator can select to turn on the ac power generation component or the energy storage component, or the control component can automatically select to turn on the ac power generation component or the energy storage component according to the current state, the selection basis can comprehensively consider the states of the ac power generation component and the energy storage component, for example, the display state of each parameter of the ac power generation component is obtained to be normal, and the electric quantity stored in the energy storage component is lower than a certain set value, and cannot support the normal operation of the system, then the ac power generation component is directly turned on to transmit electric energy to the dc bus, and for example, the display state of each parameter of the ac power generator is obtained to be abnormal, and, can support the system normal operating for a period of time, then directly open energy storage component and carry the electric energy to the direct current bus-bar, specific selection condition can be formulated according to actual conditions, also can add other judgement conditions, and it is no longer repeated here.
Similarly, in the process of system operation, in order to deal with the situation that the ac power generation component fails or the energy storage component stores low electric quantity, the control component is also required to switch the ac power generation component and the energy storage component in time, so as to ensure that one component always transmits stable voltage to the dc bus to maintain the stable operation of the system.
In addition, in order to increase the proportion of the clean energy in the system energy supply, the switching condition can be mainly based on the state change of the energy storage assembly, the energy storage assembly can transmit the electric energy when the energy of the energy storage assembly is sufficient, the energy of the energy storage assembly is immediately switched to the alternating current power generation assembly to transmit the electric energy when the energy of the energy storage assembly is insufficient, the energy storage assembly is switched back to the energy storage assembly to transmit the electric energy when the energy of the energy storage assembly is sufficient again, and the operation is repeated until the system is closed.
Optionally, the state of the ac power generation assembly further includes a switching state; the switch state comprises a pre-opening state, an opening state, a pre-closing state and a closing state; the states of the energy storage assembly further comprise working states, and the working states comprise a voltage source mode and a current source mode;
when the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for adjusting the state of the alternating current power generation assembly to be a pre-starting state and controlling the energy storage assembly to output a first preset voltage; when the voltage of the direct current bus is a first preset voltage, adjusting the state of the alternating current power generation assembly to be an opening state; when the state of the alternating current power generation assembly is an opening state, the energy storage assembly is controlled to work in a current source mode to realize switching;
when the energy storage assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for adjusting the state of the alternating current generator to be a pre-closing state and controlling the energy storage assembly to output a second preset voltage; and when the alternating current power generation assembly is detected to be in a closed state, controlling the energy storage assembly to work in a voltage source mode, and continuously outputting a second preset voltage to realize switching.
The switching state of the alternating current power generation assembly is set to be a pre-opening state, a starting state, a pre-closing state and a closing state, the working state of the energy storage assembly is set to be a voltage source mode and a current source mode, wherein the output voltage of the voltage source mode is set to be one high and one low, and the process of switching the alternating current power generation assembly and the energy storage assembly is actually the adjustment of the respective states of the two assemblies.
Optionally, the first preset voltage is greater than the output voltage of the alternating current power generation assembly;
the second preset voltage is smaller than the output voltage of the alternating current power generation assembly.
When the alternating current power generation assembly is switched to the energy storage assembly, the state of the generator is adjusted to be in a pre-closing state, the energy storage assembly is controlled to output a voltage lower than the output voltage of the alternating current power generation assembly, when the alternating current power generation assembly is detected to be in the closing state, the energy storage assembly is controlled to work in a voltage source mode, and a second preset voltage is continuously output, namely the output voltage of the energy storage assembly is lower than the output voltage of the alternating current power generation assembly.
When the energy storage assembly is switched to the alternating current power generation assembly, firstly, the output voltage is increased to exceed the output voltage of the alternating current power generation assembly, then, the alternating current power generation assembly is started, when the alternating current power generation assembly is detected to be in a starting state, the working state of the energy storage assembly is adjusted to be in a current source mode, and when the bus voltage is detected to be the output voltage of the alternating current power generation assembly, the fact that the alternating current power generation assembly outputs electric quantity to the direct current bus can be determined.
In some embodiments, to implement the functions of acquiring the state of other components and regulating according to the state, the control component comprises: the information acquisition module and the decision response module are connected;
the information acquisition module is connected with the energy storage assembly and the alternating current power generation assembly and is used for acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time;
and the decision response module is connected with the energy storage assembly and the alternating current power generation assembly and used for switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable.
Specifically, the acquisition of the state information and the corresponding adjustment control CAN be completed through communication among the control component, the alternating current power generation component and the energy storage component, the communication modes are various, for example, power line carrier communication, CAN bus communication, bluetooth communication, wireless communication and the like, the specific communication mode CAN be selected according to actual conditions, and details are not repeated here. Correspondingly, a communication module is also arranged in each component to realize communication.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a dc microgrid system according to an embodiment of the present invention. As shown in fig. 2, in the direct-current microgrid system provided by the present embodiment, the alternating-current power generation assembly 15 includes an alternating-current generator 151 and a first AC/DC converter 152; the AC generator 151 is connected to the DC bus through the first AC/DC converter 152, and supplies electric power to the DC bus.
The energy storage assembly 14 comprises an energy storage module 141 and a first DC/DC converter 142; the energy storage module 141 is connected to the DC bus 12 through the first DC/DC converter 142, stores the electric energy on the DC bus 12, and transmits the electric energy to the DC bus; the energy storage module can be devices such as a storage battery, a super capacitor and a charging pile;
the clean energy assembly 13 includes: an energy module 131; a second AC/DC converter 132 and a second DC/DC converter 133. The energy module 131 may include a photovoltaic array 1311 and a wind generating set 1312, so that electricity can be generated by solar energy and wind power. The wind turbine 1312 is connected to the direct current bus through the second AC/DC converter 132, and the photovoltaic array 1311 is connected to the direct current bus 12 through the second DC/DC converter 133 to transmit electric energy to the direct current bus 12.
The load 16 comprises a DC load 162, and the DC load 162 is connected to the DC bus 12 via a third DC/DC converter 161.
The DC/DC converter and the AC/DC converter can rectify the supplied electric energy into required direct current.
In other embodiments, the energy modules in the clean energy assembly may include one or more of a photovoltaic power generation device or a wind power generation device, and accordingly, one or more heterogeneous converters may be required to access the dc bus.
A voltage sampling circuit is integrated in the converter, so that voltage can be sampled, and the voltage corresponds to the voltage of the direct current bus.
In order to facilitate the control component to acquire the state of the alternator, a protocol may be established between the two to encode the state of the alternator, for example, the pre-on state may be set to 10, the on state may be set to 11, the pre-off state may be set to 01, and the off state may be set to 00.
In addition, the direct-current microgrid system shown in fig. 2 is a single-dimensional direct-current microgrid system, a plurality of single-dimensional direct-current microgrid systems can be combined into a multidimensional direct-current microgrid system, and the same control mode is adopted, so that the same beneficial effects are achieved.
Referring to fig. 3, fig. 3 is a flowchart of a control method of a dc microgrid system according to an embodiment of the present invention. As shown in fig. 3, the control method of the dc microgrid system provided in this embodiment is applied to the dc microgrid system in any of the above embodiments, and the control method of the dc microgrid system includes:
s301, acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time.
S302, according to the obtained states of the energy storage assembly and the alternating current power generation assembly, one of the energy storage assembly and the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus, so that the voltage on the direct current bus is kept stable.
Optionally, the state of the alternator component comprises a healthy state; the health state comprises a normal state and an abnormal state; the state of the energy storage assembly comprises an electric quantity state;
the switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly comprises:
under the condition that the energy storage assembly transmits electric energy to the direct current bus, if the electric quantity of the energy storage assembly is lower than a first threshold value and the alternating current power generation assembly is in a normal state, the alternating current power generation assembly is switched and selected to transmit the electric energy to the direct current bus;
under the condition that the alternating current power generation assembly transmits the electric energy to the direct current bus, if the alternating current power generation assembly is in an abnormal state or the electric quantity of the energy storage assembly is higher than a second threshold value, the energy storage assembly is switched and selected to transmit the electric energy to the direct current bus.
Optionally, the state of the ac power generation assembly further includes a switch state; the switch state comprises a pre-opening state, an opening state, a pre-closing state and a closing state; the states of the energy storage assembly further comprise working states, and the working states comprise a voltage source mode and a current source mode;
the alternating current power generation assembly is switched to transmit electric energy to the direct current bus, the state of the alternating current power generation assembly is adjusted to be a pre-starting state, and the energy storage assembly is controlled to output a first preset voltage; when the voltage of the direct current bus is the first preset voltage, adjusting the state of the alternating current power generation assembly to be a starting state; when the state of the alternating current power generation assembly is an opening state, the energy storage assembly is controlled to work in a current source mode to realize switching;
the switching selection is performed on the energy storage assembly to transmit electric energy to the direct current bus, the alternating current generator is adjusted to be in a pre-closing state, and the energy storage assembly is controlled to output a second preset voltage; and when the alternating current power generation assembly is detected to be in a closed state, controlling the energy storage assembly to work in a voltage source mode, and continuously outputting the second preset voltage to realize switching.
Optionally, the first preset voltage is greater than the output voltage of the alternating current power generation assembly;
the second preset voltage is smaller than the output voltage of the alternating current power generation assembly.
The present embodiment has the same technical features as any embodiment of the above dc microgrid system, and specific implementation manners may refer to the above embodiments to produce the same beneficial effects, and details are not described here.
It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.
It should be noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (8)
1. A direct current microgrid system, comprising: the device comprises a control assembly, a direct current bus, a clean energy assembly connected to the direct current bus, an energy storage assembly and an alternating current power generation assembly;
the clean energy assembly is used for transmitting electric energy to the direct current bus;
the energy storage assembly is used for storing electric energy on the direct current bus;
the control assembly is connected with the energy storage assembly and the alternating current power generation assembly and is used for acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time and switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable;
the direct current bus is also used for connecting a direct current load to supply power;
the state of the alternator component comprises a healthy state; the health state comprises a normal state and an abnormal state; the state of the energy storage assembly comprises an electric quantity state;
when one of the energy storage assembly and the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly, the control assembly is specifically configured to:
under the condition that the energy storage assembly transmits electric energy to the direct current bus, if the electric quantity of the energy storage assembly is lower than a first threshold value and the alternating current power generation assembly is in a normal state, the alternating current power generation assembly is switched and selected to transmit the electric energy to the direct current bus;
under the condition that the alternating current power generation assembly transmits electric energy to the direct current bus, if the alternating current power generation assembly is in an abnormal state or the electric quantity of the energy storage assembly is higher than a second threshold value, the energy storage assembly is switched and selected to transmit the electric energy to the direct current bus;
the state of the alternating current power generation assembly also comprises a switch state; the switch state comprises a pre-opening state, an opening state, a pre-closing state and a closing state; the states of the energy storage assembly further comprise working states, and the working states comprise a voltage source mode and a current source mode;
when the alternating current power generation assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for adjusting the state of the alternating current power generation assembly to be a pre-starting state and controlling the energy storage assembly to output a first preset voltage; when the voltage of the direct current bus is the first preset voltage, adjusting the state of the alternating current power generation assembly to be a starting state; when the state of the alternating current power generation assembly is an opening state, the energy storage assembly is controlled to work in a current source mode to realize switching;
when the energy storage assembly is switched and selected to transmit electric energy to the direct current bus, the control assembly is specifically used for adjusting the state of the alternating current generator to be a pre-closed state and controlling the energy storage assembly to output a second preset voltage; and when the alternating current power generation assembly is detected to be in a closed state, controlling the energy storage assembly to work in a voltage source mode, and continuously outputting the second preset voltage to realize switching.
2. The direct current microgrid system of claim 1, wherein the first preset voltage is greater than an output voltage of the alternating current power generation assembly;
the second preset voltage is smaller than the output voltage of the alternating current power generation assembly.
3. The direct current microgrid system of claim 1, wherein the control component comprises: the information acquisition module and the decision response module are connected;
the information acquisition module is connected with the energy storage assembly and the alternating current power generation assembly and is used for acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time;
the decision response module is connected with the energy storage assembly and the alternating current power generation assembly and used for switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable.
4. The direct current microgrid system of claim 1, wherein the alternating current power generation assembly comprises: an alternator and a first AC/DC converter;
the alternating current generator is connected into the direct current bus through the first AC/DC converter and transmits electric energy to the direct current bus.
5. The direct current microgrid system of claim 1, wherein the energy storage component comprises: the energy storage module and the first DC/DC converter;
the energy storage module is connected to the direct current bus through the first DC/DC converter, stores electric energy on the direct current bus and transmits the electric energy to the direct current bus.
6. The direct current microgrid system of claim 1, wherein the clean energy components comprise: an energy module; a second AC/DC converter and/or a second DC/DC converter;
the energy module is connected to the direct current bus through the second AC/DC converter and/or the second DC/DC converter, and electric energy is transmitted to the direct current bus.
7. A control method of a direct current microgrid system, characterized in that the method is applied to the direct current microgrid system as claimed in any one of claims 1-6, and comprises the following steps:
acquiring the state of the energy storage assembly and the state of the alternating current power generation assembly in real time;
and switching and selecting one of the energy storage assembly and the alternating current power generation assembly to transmit electric energy to the direct current bus according to the acquired state of the energy storage assembly and the state of the alternating current power generation assembly so as to keep the voltage on the direct current bus stable.
8. The method for controlling the direct current microgrid system of claim 7, wherein if the state of the alternating current power generation component comprises a healthy state; the health state comprises a normal state and an abnormal state; the state of the energy storage assembly comprises an electric quantity state;
the switching selection of one of the energy storage component and the alternating current power generation component to transmit electric energy to the direct current bus according to the obtained state of the energy storage component and the state of the alternating current power generation component comprises:
under the condition that the energy storage assembly transmits electric energy to the direct current bus, if the electric quantity of the energy storage assembly is lower than a first threshold value and the alternating current power generation assembly is in a normal state, the alternating current power generation assembly is switched and selected to transmit the electric energy to the direct current bus;
under the condition that the alternating current power generation assembly transmits the electric energy to the direct current bus, if the alternating current power generation assembly is in an abnormal state or the electric quantity of the energy storage assembly is higher than a second threshold value, the energy storage assembly is switched and selected to transmit the electric energy to the direct current bus.
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