CN110970943A - Hybrid micro-grid system and control method thereof - Google Patents

Hybrid micro-grid system and control method thereof Download PDF

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CN110970943A
CN110970943A CN201911330793.2A CN201911330793A CN110970943A CN 110970943 A CN110970943 A CN 110970943A CN 201911330793 A CN201911330793 A CN 201911330793A CN 110970943 A CN110970943 A CN 110970943A
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power
converter
network
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alternating current
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CN110970943B (en
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蹇林旎
喻航
尚一通
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Southern University of Science and Technology
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Southern University of Science and Technology
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers

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  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The embodiment of the invention discloses a hybrid micro-grid system and a control method thereof. This hybrid microgrid system includes: the central control unit is respectively in communication connection with the bidirectional DC/AC converter and the bidirectional DC/DC converter, wherein the direct current side of the bidirectional DC/AC converter is connected with a first direct current bus, and the battery is connected with the first direct current bus through the bidirectional DC/DC converter; the direct-current sub-network is connected with a second direct-current bus, the second direct-current bus is connected with the first direct-current bus, and the direct-current sub-network at least comprises a direct-current power generation device and a direct-current controllable load; the alternating current side of the bidirectional DC/AC converter is connected with an external network and an alternating current bus, and an alternating current sub-network is connected with the alternating current bus; the ac sub-network comprises at least an ac power generating device and an ac controllable load. The hybrid micro-grid system has the advantages of high efficiency, flexible control and strong risk resistance.

Description

Hybrid micro-grid system and control method thereof
Technical Field
The embodiment of the invention relates to the technical field of micro-grid operation control, in particular to a hybrid micro-grid system and a control method thereof.
Background
In recent years, distributed renewable energy represented by photovoltaic and wind power is widely applied, and a microgrid serving as a small power system integrating a distributed power supply, energy storage, load and a control network is an effective way for overcoming the intermittency and randomness of the power generation of the renewable energy and improving the power supply quality and the operation stability of the system. In modern buildings, a building distribution network is constructed in a micro-grid mode, high-density renewable energy power generation can be achieved, and high-quality energy conservation and emission reduction effects are achieved.
However, the application of the micro-grid in buildings has shortcomings. Firstly, in terms of system architecture, a traditional microgrid usually belongs to an alternating current microgrid, but with the popularization of direct current distributed power sources (such as photovoltaic) and direct current loads (such as electric vehicles) in buildings, the practical requirement of high-efficiency utilization of energy cannot be met by a mode that the direct current power sources and the loads are compatible with an alternating current system only through a direct current/alternating current conversion unit. Moreover, too many transform units increase the complexity of the system. In addition, various operation scenes of the system are not fully considered in the traditional micro-grid architecture, and the traditional architecture cannot realize a multi-element control target under the condition of grid connection or grid disconnection; in the face of a fault situation, the traditional architecture does not have certain risk resistance, so that continuous power supply to a certain degree is guaranteed. Secondly, in the aspect of a system control method, the existing micro-grid system control method is usually specific to a traditional architecture, and the control targets mainly comprise the steps of realizing load sharing among distributed power supplies, specifying power output to participate in demand correspondence, ensuring stable operation of the system and the like.
The operational flexibility of the system is reduced due to the structural singleness and the imperfection of the control method, the complex working conditions are difficult to face, and the high-proportion local consumption of distributed energy resources cannot be realized.
Disclosure of Invention
The embodiment of the invention provides a hybrid micro-grid system and a control method thereof, and provides a micro-grid system which comprises an alternating current sub-network and is compatible with a direct current sub-network, so that direct current loads and direct current distributed power sources are efficiently integrated, and the system efficiency is improved.
In a first aspect, an embodiment of the present invention provides a hybrid microgrid system, including: a central control unit, a bidirectional DC/AC converter, a bidirectional DC/DC converter, a battery, a DC sub-network and an AC sub-network, wherein the central control unit is respectively connected with the bidirectional DC/AC converter and the bidirectional DC/DC converter in a communication way,
the direct current side of the bidirectional DC/AC converter is connected with a first direct current bus, and the battery is connected with the first direct current bus through the bidirectional DC/DC converter; the direct-current sub-network is connected with a second direct-current bus, the second direct-current bus is connected with the first direct-current bus, and the direct-current sub-network at least comprises a direct-current power generation device and a direct-current controllable load;
the alternating current side of the bidirectional DC/AC converter is connected with an external network and an alternating current bus, and the alternating current sub-network is connected with the alternating current bus; the alternating current sub-network at least comprises an alternating current power generation device and an alternating current controllable load.
In a second aspect, an embodiment of the present invention further provides a control method for a hybrid microgrid system, where the control method is applied to the hybrid microgrid system according to any embodiment of the present invention, and the control method includes:
acquiring the state of charge of a battery;
and adjusting the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the working mode of the microgrid.
The hybrid microgrid system provided by the embodiment of the invention not only contains an alternating current subnet, is convenient for the access of an alternating current load and an alternating current distributed power supply, but also is compatible with a direct current subnet, efficiently integrates the direct current load and the direct current distributed power supply, reduces the number of converters and improves the efficiency of the system compared with an independent alternating current or direct current microgrid; the central control unit is respectively connected with the bidirectional DC/AC converter and the bidirectional DC/DC converter, so that the central controller can change the operation mode of the converter, adjust energy circulation channels of the battery, the direct current sub-network and the alternating current sub-network, further manage the energy of the microgrid, provide effective power support for the alternating current sub-network and the direct current sub-network, improve the utilization efficiency and the local consumption efficiency of distributed renewable energy sources, and ensure the stable operation of the system. The mixed micro-grid system provided by the embodiment is particularly suitable for modern buildings with mixed alternating current and direct current, and the micro-grid architecture has the advantages of high efficiency, flexibility in control and strong risk resistance.
Drawings
Fig. 1 is a schematic structural diagram of a hybrid microgrid system provided by an embodiment of the present invention;
fig. 2 is a flowchart of a control method of a hybrid microgrid system provided by an embodiment of the present invention;
fig. 3 is a flowchart of a control method for the microgrid system when the microgrid system is in a grid-connected mode and a battery SoC is within a normal threshold range according to the embodiment of the present invention;
fig. 4 is a flowchart of a control method for the microgrid system when the microgrid system is in a grid-connected mode and a battery SoC exceeds an upper limit threshold value, according to an embodiment of the present invention;
fig. 5 is a flowchart of a control method for the microgrid system when the microgrid system is in a grid-connected mode and a battery SoC is lower than a lower threshold value according to an embodiment of the present invention;
fig. 6 is a flowchart of a method for controlling the microgrid system in an off-grid mode according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a hybrid microgrid system according to an embodiment of the present invention, which is applicable to a case where a dc subnet and an ac subnet are connected, as shown in fig. 1, the hybrid microgrid system includes:
a central control unit 1, a bidirectional DC/AC converter 3, a bidirectional DC/DC converter 41, a battery 43, a DC sub-network and an AC sub-network, the central control unit 1 being in communication connection with the bidirectional DC/AC converter 3, the bidirectional DC/DC converter 41, respectively, wherein,
the direct current side of the bidirectional DC/AC converter 3 is connected with a first direct current bus 5, and the battery 43 is connected with the first direct current bus 5 through the bidirectional DC/DC converter 41; the direct-current sub-network is connected with a second direct-current bus 4, the second direct-current bus 4 is connected with a first direct-current bus 5, and the direct-current sub-network at least comprises a direct-current power generation device and a direct-current controllable load;
the alternating current side of the bidirectional DC/AC converter 3 is connected with an external network and an alternating current bus 6, and an alternating current sub-network is connected with the alternating current bus 6; the ac sub-network comprises at least an ac power generating device and an ac controllable load.
The central control unit 1 is used for monitoring and controlling power of the whole microgrid so as to ensure that the microgrid can work normally.
Through setting up two-way DC/AC converter 3 for the microgrid that this embodiment provided has possessed the ability of connecting direct current subnet and interchange subnet to and the ability of being connected with the outer net, thereby provides a novel microgrid framework. Meanwhile, the bidirectional DC/AC converter 3 and the bidirectional DC/DC converter 41 are in communication connection with the central control unit 1, and the central control unit 1 can directly control the operation modes of the bidirectional DC/AC converter 3 and the bidirectional DC/DC converter 41 according to the current operation state of the microgrid.
The second direct current bus 4 can be used for connecting a distributed direct current power supply and a direct current load; the alternating current bus 6 can be used for connecting a distributed alternating current power supply and an alternating current load.
The battery 43 is connected with the first DC bus 5 through the bidirectional DC/DC converter 41, each power source and load in the DC sub-network is connected with the second DC bus 4, and the second DC bus 4 is connected with the first DC bus 5, so that a connection channel is established between the battery 43 and the DC sub-network. At the same time, the DC sub-network and the AC sub-network are connected by the bidirectional DC/AC converter 3, so that a connection path is also established between the battery 43 and the AC sub-network. The alternating current side of the bidirectional DC/AC converter 3 is connected with the external grid, and a connecting channel between the microgrid and the external grid is established, so that the microgrid provided by the embodiment can perform energy interaction with the external grid.
In one embodiment, the bidirectional DC/AC converter 3 comprises a first converter 31 and a second converter 32 arranged back to back, specifically, the DC side of the first converter 31 and the DC side of the second converter 32 are connected to the first DC bus 5; the control port of the first converter 31 and the control port of the second converter 32 are respectively connected with the central control unit 1; the ac side of the second converter 32 is connected to the ac busbar 6, the ac feeder 9 of the first converter is connected to the first ac power source 21 via a first controllable switch k1, and the ac feeder 7 of the second converter is connected to the second ac power source 22 via a second controllable switch k 2.
The alternating current feeder 9 of the first converter and the alternating current feeder 7 of the second converter are connected through a tie line 8, a third controllable switch k3 is arranged on the tie line 8, and a control end of each controllable switch is connected to the central control unit 1.
Wherein, the bidirectional DC/AC converter 3 arranged back to back provides multi-level AC/DC conversion, and the battery 43 at the additional DC side and the bidirectional DC/DC converter 41 realize rich control functions.
The control ends of the three controllable switches are directly connected with the central control unit 1 respectively, so that the central control unit 1 can control the micro-grid to be in a grid-connected mode or an off-grid mode by controlling the on-off states of the three controllable switches, and the flexible transformation of the micro-grid structure is realized. Specifically, by controlling the first controllable switch k1 and the second controllable switch k2 to be closed, the microgrid can be controlled to be in a grid-connected mode; the microgrid can be controlled to be in an off-grid mode by controlling the first controllable switch k1 and the second controllable switch k2 to be turned off; by controlling the third controllable switch k3 to close when the microgrid is in an off-grid mode, a power flow path between the first converter 31 and the second converter 32 can be provided. When the micro-grid fails in the bidirectional DC/AC converter 3, the battery 43 or the bidirectional DC/DC converter 41 connected with the battery 43, so that the direct-current sub-network cannot work normally, the first controllable switch k1 and the third controllable switch k3 can be controlled to be closed independently, or the second controllable switch k2 and the third controllable switch k3 are controlled to be closed independently, so that the normal operation of the alternating-current sub-network is ensured. The central control unit 1 can change the topological structure of the microgrid system by directly controlling the controllable switches so as to meet different control requirements.
In addition, the ac side of the first converter 31 is connected to the first ac power source 21, and the ac side of the second converter 32 is connected to the second ac power source 22, so that the microgrid system provided by the present embodiment can perform energy interaction with an external grid from both ac sides.
In one embodiment, the DC power generation apparatus includes a photovoltaic system and a first DC/DC converter 45, the photovoltaic system is connected to the second DC bus 4 through the first DC/DC converter 45; the DC controllable load is connected to the second DC bus 4 via a second DC/DC converter 44.
In one embodiment, the AC power generation device comprises a wind power system and an AC/DC/AC converter 61, the wind power system being connected to the AC bus 6 via the AC/DC/AC converter 61.
As shown in fig. 1, the ac power generation device, the ac controllable load, the dc power generation device and the dc controllable load are all provided with Local Controllers (LC), and the Local controllers directly monitor and manage the connected units; each local controller is in communication connection with the central control unit 1, receives a control instruction of the central control unit 1, enables each unit to respond to the control of the central control unit 1 to adjust the operation mode of the unit, and can feed back related information to the central control unit 1.
The battery 43 is provided with a battery controller through which the battery 43 is communicatively connected with the central control unit 1, so that the central control unit 1 can monitor and manage the battery 43.
In addition, the second dc bus feeder port 42 and the ac bus feeder port 62 are each communicatively connected to the central control unit 1. The central control unit can monitor the voltage, frequency, current and other information of the direct current bus and the alternating current bus in real time, and therefore energy management of the alternating current/direct current sub-network is facilitated in a centralized mode.
The direct current side of the bidirectional DC/AC converter 3 is connected to the first direct current bus 5, so that the central control unit 1 can monitor information such as voltage and current of the first direct current bus 5 in real time.
The hybrid microgrid system provided by the embodiment of the invention not only contains an alternating current subnet, is convenient for the access of an alternating current load and an alternating current distributed power supply, but also is compatible with a direct current subnet, efficiently integrates the direct current load and the direct current distributed power supply, reduces the number of converters and improves the efficiency of the system compared with an independent alternating current or direct current microgrid; the central control unit is respectively connected with the bidirectional DC/AC converter and the bidirectional DC/DC converter, so that the central controller can change the operation mode of the converter, can control the energy flow of the battery, the direct current sub-network and the alternating current sub-network, can manage the energy of the micro-grid, provides effective power support for the alternating current sub-network and the direct current sub-network, improves the utilization efficiency and the local consumption efficiency of distributed renewable energy sources, and ensures the stable operation of the system. The mixed micro-grid system provided by the embodiment is particularly suitable for modern buildings with mixed alternating current and direct current, and the micro-grid architecture has the advantages of high efficiency, flexibility in control and strong risk resistance.
Based on the foregoing microgrid system, the present embodiment further provides a control method for a hybrid microgrid, and fig. 2 is a flowchart of the control method for the hybrid microgrid system provided in the present embodiment, specifically, the method includes:
and S210, acquiring the charge state of the battery.
The state of charge of the battery is used to reflect the remaining capacity of the battery, and is usually represented by soc (state of charge). The SoC value represents a ratio of the remaining capacity of the battery to the battery capacity, and is expressed as a percentage.
In order to manage the battery conveniently and prevent the battery from being damaged due to overcharge or overdischarge, in one embodiment, a normal threshold, an upper limit threshold and a lower limit threshold are set for the battery, and specifically, when the SoC is less than 10% < 90%, the state of charge of the battery is in a normal threshold range; when the SoC reaches 90% and is not reduced to less than 80% subsequently, it indicates that the remaining capacity of the battery is in a state close to saturation, and the SoC is at an upper limit threshold, and at this time, if the dc sub-network or the ac sub-network needs capacity, a certain margin power can be obtained from the battery, but the battery cannot be in a charging mode at this time; when the SoC reaches 10% and is not subsequently recovered to more than 20%, it indicates that the remaining power of the battery is in a low power state, and the SoC is in a lower limit threshold, and at this time, if the power of the dc sub-network and/or the ac sub-network is remaining, the battery may be charged with surplus power, but at this time, the battery may not be in a discharge mode.
S220, adjusting the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the working mode of the microgrid.
The working mode of the microgrid refers to whether the microgrid is connected with an external grid or not, namely grid-connected operation or off-grid operation. The micro-grid can actively adjust the working mode of the micro-grid by controlling the state of the controllable switch according to the monitoring result of the external network. In one embodiment, before adjusting the operation modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the operation mode of the microgrid, the method further comprises the following steps:
if the fault of the external grid is detected, the first controllable switch and the second controllable switch are controlled to be disconnected, and the third controllable switch is controlled to be connected, so that the microgrid is in an off-grid mode;
and if the external grid has no fault, controlling the first controllable switch and the second controllable switch to be switched on, and controlling the third controllable switch to be switched off, so that the micro-grid is in a grid-connected mode.
The micro-grid can adopt an island detection technology to monitor the external grid in real time. When the external grid is detected to have a fault, the central control unit controls the first controllable switch and the second switch to be switched off, so that the microgrid is in an off-grid mode, and correspondingly, when the microgrid is in the off-grid mode, the central control unit controls the third controllable switch to be switched on, so that an energy flow channel between the first converter and the second converter can be provided.
In the embodiment, the state of charge of the battery is monitored through the central control unit, the electric quantity information of the battery is acquired, the energy circulation channels of the battery, the direct current sub-network and the alternating current sub-network can be adjusted by adjusting the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the electric quantity information of the battery and the working mode of the microgrid, so that the energy of the microgrid can be managed, effective power support is provided for the alternating current sub-network and the direct current sub-network, the utilization efficiency and the local consumption efficiency of distributed renewable energy sources are improved, and the stable operation of the system is ensured.
On the basis of the above technical solution, optionally, after adjusting the operating modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter, the hybrid microgrid control method further includes:
s230, acquiring net power of the direct current sub-network
Figure BDA0002329500080000091
And net power of AC sub-network
Figure BDA0002329500080000092
The net power of the direct current sub-network is obtained by low-pass filtering the current power of the direct current sub-network, and the net power of the alternating current sub-network is obtained by low-pass filtering the current power of the alternating current sub-network.
The central control unit can acquire the current power of the direct-current sub-network by monitoring the second direct-current bus, and can acquire the current power of the alternating-current sub-network by monitoring the alternating-current bus.
The purpose of filtering the current power of the direct current sub-network and the current power of the alternating current sub-network is to obtain stable surplus power or missing power before power scheduling, and avoid frequent system response caused by power value fluctuation, thereby generating adverse effects on system stability.
And S240, adjusting the power distribution of the direct current sub-network, the alternating current sub-network and the battery according to the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter, and the net power of the direct current sub-network and the net power of the alternating current sub-network so as to control the micro-grid to keep energy supply and demand balance.
The central control unit can control the energy flow of the direct current sub-network, the alternating current sub-network and the battery by adjusting the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter. And adjusting the energy flow direction by combining the net power of the direct current sub-network and the net power of the alternating current sub-network, finally realizing energy management on the micro-grid and ensuring that the micro-grid system can stably operate.
When the micro-grid is controlled, comprehensive consideration needs to be carried out according to the net power condition of the direct-current sub-network, the net power condition of the alternating-current sub-network and the current SoC of the battery, and then mutual support of the alternating-current sub-network and the direct-current sub-network power is realized by adjusting the power distribution of the bidirectional DC/AC converter and the bidirectional DC/DC converter, so that the local consumption of distributed energy is improved, the over-charge and over-discharge of the energy storage battery are prevented, and the stable operation of the system is ensured.
The following further describes the control method of the microgrid under different working conditions with reference to specific examples.
In one embodiment, if the microgrid is in a grid-connected mode, adjusting the operating modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the operating mode of the microgrid includes:
if the state of charge of the battery is in a normal threshold range, controlling the first converter and the second converter to be in a power control mode, and controlling the bidirectional DC/DC converter to be in a voltage stabilization mode;
and if the state of charge of the battery is in a lower limit threshold or an upper limit threshold, controlling the first converter to be in a voltage stabilizing mode, and controlling the second converter and the bidirectional DC/DC converter to be in a power control mode.
When the state of charge of the battery is in a normal threshold range, the first converter and the second converter are in a power control mode and can receive a power scheduling command from the central control unit, wherein a positive value indicates that the power flow flows from a direct current side to an alternating current side, and a negative value indicates that the power flow flows from the alternating current side to the direct current side. The DC/DC is in a voltage stabilizing mode, and can maintain the DC bus voltage stable, and in one embodiment, the progenitor voltage of the DC bus voltage is 700V, which can satisfy most DC load requirements.
When the state of charge of the battery is at the lower limit threshold or the upper limit threshold, in order to prevent the battery from being overcharged or overdischarged, the bidirectional DC/DC converter is switched into a power control mode, and a power scheduling instruction of the central control unit can be received
Figure BDA0002329500080000111
Wherein positive values indicate that the battery power is output to the direct current bus, and negative values indicate that the battery absorbs certain power from the direct current bus. The first converter is switched to a regulated mode,for stabilizing the dc bus voltage, the second converter remains in power control mode.
Fig. 3 is a flowchart of a control method for the microgrid system when the microgrid system is in a grid-connected mode and a battery SoC is in a normal threshold range, where in this working condition, the first converter and the second converter are in a power control mode, receive a power scheduling instruction from the central control unit, and the bidirectional DC/DC converter is in a voltage stabilization mode to maintain a 700V DC bus voltage. Under the working condition, the energy management control method is designed by referring to the net power conditions of the alternating current sub-network and the direct current sub-network. When the active power is output by the alternating current sub-network and the direct current sub-network, the net power is positive, and the generated surplus power is balanced by the large power grid and the battery respectively; when one sub-network absorbs external active power, the net power is negative, and the net power of the other sub-network is positive, the surplus power of the other sub-network is dispatched to the power deficiency side through the second converter, so that power support among the sub-networks is realized, and local consumption of distributed energy is improved. When the net power of the direct current sub-network and the alternating current sub-network is negative, the corresponding missing power is supplemented by the battery and the external network. The method specifically comprises the following steps:
s310, obtaining the current power delta P of the DC sub-networkDCAnd the current power Δ P of the AC sub-networkAC。
S320, current power delta P to the direct current sub-networkDCLow-pass filtering to obtain net power of DC sub-network
Figure BDA0002329500080000112
S330, current power delta P to AC sub-networkACLow-pass filtering to obtain net power of AC sub-network
Figure BDA0002329500080000113
Wherein, Δ PDCRepresenting the output power P of distributed units in a DC sub-networkDG_dcAnd a DC load PLoad_dcThe difference between the two; delta PACRepresenting distributed unit output power in an AC subnetworkPDG_acWith an AC load PLoad_acThe difference between them. For Δ PDC、ΔPACThe low-pass filtered value is
Figure BDA0002329500080000114
S340, judging whether the second direct current bus outputs power or absorbs power, wherein when the second direct current bus outputs power, net power of the direct current sub-network
Figure BDA0002329500080000121
Is a positive value; net power of the DC sub-network when the second DC bus absorbs power
Figure BDA0002329500080000122
Is negative.
S350, judging whether the alternating current bus outputs power or absorbs power, wherein when the alternating current bus outputs power, net power of the alternating current sub-network
Figure BDA0002329500080000123
Is a positive value; net power of AC sub-network when AC bus absorbs power
Figure BDA0002329500080000124
Is negative.
S360, if
Figure BDA0002329500080000125
And is
Figure BDA0002329500080000126
The power of the first converter is set to zero and the power of the second converter is set to zero
Figure BDA0002329500080000127
And controlling the surplus power of the alternating current sub-network to charge the battery.
Wherein the central control unit sets the first converter power to
Figure BDA0002329500080000128
Setting the second converter power to
Figure BDA0002329500080000129
At the moment, the surplus power of the direct current sub-network and the alternating current sub-network is balanced by the battery.
S370, if
Figure BDA00023295000800001210
And is
Figure BDA00023295000800001211
The power of the first converter is set to zero and the power of the second converter is set to zero
Figure BDA00023295000800001212
The surplus power of the direct current sub-network is scheduled to the alternating current sub-network, and the missing power of the alternating current sub-network is made up.
Wherein the central control unit is provided with a first converter power
Figure BDA00023295000800001213
Setting the second converter power
Figure BDA00023295000800001214
The surplus power of the direct current sub-network is independently utilized, or the surplus power of the direct current sub-network is utilized to compensate the missing power of the alternating current sub-network by utilizing the surplus power of the direct current sub-network and the difference power supplemented by the battery.
S380, if
Figure BDA00023295000800001215
And is
Figure BDA00023295000800001216
The power of the first converter is set to zero and the power of the second converter is set to zero
Figure BDA00023295000800001217
To dispatch the surplus power of AC sub-network to DC sub-network to make up for DC sub-networkPower is lost.
Wherein,
Figure BDA00023295000800001218
the surplus power of the alternating current sub-network is used alone or the surplus power of the alternating current sub-network is used for compensating the missing power of the alternating current sub-network by the surplus power supplemented by the additional battery. .
S390, if
Figure BDA00023295000800001219
And is
Figure BDA00023295000800001220
The power of the first converter and the power of the second converter are both set to be zero, and the alternating current sub-network and the direct current sub-network are controlled not to generate power interaction.
Wherein the central control unit is provided with
Figure BDA0002329500080000131
And when the current is zero, the missing power of the direct current sub-network is balanced by the battery, and the missing power of the alternating current sub-network is balanced by the large power grid connected to the second converter side.
Fig. 4 is a flowchart of a control method for the microgrid system when the microgrid system is in a grid-connected mode and the SoC of the battery is at an upper threshold, where the SoC is at the upper threshold, that is, the SoC value reaches 90% and is not subsequently reduced to less than 80%, under the working condition, in order to prevent the battery from being overcharged, the bidirectional DC/DC converter is switched to a power control mode, a power scheduling instruction of the central control unit is received, the first converter is switched to a voltage stabilization mode for stabilizing the voltage of the direct-current bus, and the second converter still maintains the power control mode. Under the working condition, the design purpose of the energy management control method is to realize power complementation between the alternating current sub-network and the direct current sub-network, and it is noted that when the SoC value of the battery exceeds an upper limit threshold value, the battery cannot be in a charging state, and the surplus power of the direct current sub-network can be absorbed by the large power grid and the alternating current sub-network. The method specifically comprises the following steps:
s410, obtaining the current power delta P of the direct current sub-networkDCAnd exchange of subnetsFront power Δ PAC。
S420, current power delta P to the direct current sub-networkDCLow-pass filtering to obtain net power of DC sub-network
Figure BDA0002329500080000132
S430, current power delta P to AC sub-networkACLow-pass filtering to obtain net power of AC sub-network
Figure BDA0002329500080000137
S440, judging whether the second direct current bus outputs power or absorbs power, wherein when the second direct current bus outputs power, net power of the direct current sub-network
Figure BDA0002329500080000133
Is a positive value; net power of the DC sub-network when the second DC bus absorbs power
Figure BDA0002329500080000134
Is negative.
S450, judging whether the alternating current bus outputs power or absorbs power, wherein when the alternating current bus outputs power, the net power of the alternating current sub-network
Figure BDA0002329500080000135
Is a positive value; net power of AC sub-network when AC bus absorbs power
Figure BDA0002329500080000136
Is negative.
S460, if
Figure BDA0002329500080000141
And is
Figure BDA0002329500080000142
The power of both the second converter and the bidirectional DC/DC converter is set to zero to dispatch the surplus power of the DC sub-network to the first ac power source toAnd dispatching the surplus power of the alternating current sub-network to a second alternating current power supply;
wherein the central control unit is provided with a second converter power
Figure BDA0002329500080000143
Setting bidirectional DC/DC converter power
Figure BDA0002329500080000144
At the moment, the surplus power of the direct-current sub-network is automatically balanced by the first converter and is output to the first large power grid on the corresponding side, and the surplus power of the alternating-current sub-network is automatically balanced by the second large power grid on the other side.
S470, if
Figure BDA0002329500080000145
And is
Figure BDA0002329500080000146
The power of the second converter is set to
Figure BDA0002329500080000147
Setting power of a bidirectional DC/DC converter to
Figure BDA0002329500080000148
The surplus power of the direct current sub-network is scheduled to the alternating current sub-network, and the difference power is supplemented through the battery;
wherein the central control unit is provided with a second converter power
Figure BDA0002329500080000149
Setting power of a bidirectional converter
Figure BDA00023295000800001410
The surplus power of the direct current sub-network is independently utilized, or the surplus power of the direct current sub-network is utilized to compensate the loss of the active power of the alternating current sub-network by the difference power supplemented by the surplus power additional battery.
S480, if
Figure BDA00023295000800001411
And is
Figure BDA00023295000800001412
The power of the second converter is set to
Figure BDA00023295000800001413
Setting power of a bidirectional DC/DC converter to
Figure BDA00023295000800001414
The surplus power of the alternating current sub-network is dispatched to the direct current sub-network, and the difference power is supplemented through the battery;
wherein the central control unit is provided with a second converter power
Figure BDA00023295000800001415
Setting bidirectional DC/DC converter power
Figure BDA00023295000800001416
The surplus power of the alternating current sub-network is independently utilized, or the surplus power of the alternating current sub-network is utilized to compensate the loss of the active power of the direct current sub-network by the difference power supplemented by the surplus power additional battery.
S490, if
Figure BDA00023295000800001417
And is
Figure BDA00023295000800001418
The power of the bidirectional DC/DC converter is set to
Figure BDA00023295000800001419
The power of the second converter is set to zero to supplement the missing power of the dc sub-network by the battery and to supplement the missing power of the ac sub-network by the second ac power supply.
Wherein the central control unit is provided with a second converter power
Figure BDA0002329500080000151
Setting bidirectional DC/DC converter power
Figure BDA0002329500080000152
At the moment, the missing power of the direct current sub-network is balanced by the battery, and the missing power of the alternating current sub-network is balanced by the second large power grid.
Fig. 5 is a flowchart of a control method for the microgrid system when the microgrid system is in a grid-connected mode and a battery SoC is at a lower threshold, where a SoC value of the battery is lower than the lower threshold, that is, the SoC value reaches 10% and is not recovered to be greater than 20%, under the working condition, to prevent the battery from being over-discharged, the bidirectional DC/DC converter is switched to a power control mode, a power scheduling instruction of the central control unit is received, the first converter is switched to a voltage stabilization mode for stabilizing a voltage of a direct current bus, and the second converter still maintains the power control mode. Under the working condition, the design purpose of the energy management control method is to realize the power complementation between the alternating current sub-network and the direct current sub-network. It should be noted that, under this condition, the battery cannot be in a discharge state, and the missing power of the dc sub-network is supplemented by the surplus power of the large power grid and the ac sub-network. The method specifically comprises the following steps:
s510, obtaining the current power delta P of the direct current sub-networkDCAnd the current power Δ P of the AC sub-networkAC。
S520, current power delta P to the direct current sub-networkDCLow-pass filtering to obtain net power of DC sub-network
Figure BDA0002329500080000153
S530, current power delta P to AC sub-networkACLow-pass filtering to obtain net power of AC sub-network
Figure BDA0002329500080000154
S540, judging whether the second direct current bus outputs power or absorbs power, wherein when the second direct current bus outputs power, net power of the direct current sub-network
Figure BDA0002329500080000155
Is positiveA value; net power of the DC sub-network when the second DC bus absorbs power
Figure BDA0002329500080000156
Is negative.
S550, judging whether the alternating current bus outputs power or absorbs power, wherein when the alternating current bus outputs power, the net power of the alternating current sub-network
Figure BDA0002329500080000157
Is a positive value; net power of AC sub-network when AC bus absorbs power
Figure BDA0002329500080000161
Is negative.
S560, if
Figure BDA0002329500080000162
And is
Figure BDA0002329500080000163
The power of the second converter is set to
Figure BDA0002329500080000164
Setting power of a bidirectional DC/DC converter to
Figure BDA0002329500080000165
The surplus power of the alternating current sub-network and the direct current sub-network is controlled to charge the battery;
wherein the central control unit is provided with a second converter power
Figure BDA0002329500080000166
Setting bidirectional DC/DC converter power
Figure BDA0002329500080000167
At the moment, the surplus power of the direct current sub-network and the surplus power of the alternating current sub-network are balanced by the battery.
S570, if
Figure BDA0002329500080000168
And is
Figure BDA0002329500080000169
The power of the second converter is set to zero, the power of the bidirectional DC/DC converter is set to,
Figure BDA00023295000800001610
and controlling the surplus power of the direct current sub-network to charge the battery.
Wherein the central control unit is provided with a second converter power
Figure BDA00023295000800001611
Setting bidirectional DC/DC converter power
Figure BDA00023295000800001612
At the moment, the surplus power of the direct current sub-network is balanced by the battery so as to recover the SoC value of the battery to a normal threshold range as soon as possible, and the surplus power of the alternating current sub-network is automatically balanced by the second large power grid.
S580, if
Figure BDA00023295000800001613
And is
Figure BDA00023295000800001614
The power of the second converter is set to
Figure BDA00023295000800001615
Setting power of a bidirectional DC/DC converter to
Figure BDA00023295000800001616
The surplus power of the alternating current sub-network is controlled to supplement the missing power of the direct current sub-network preferentially, and the surplus power is used for charging the battery;
wherein the central control unit is provided with a second converter power
Figure BDA00023295000800001617
Setting bidirectional DC/DC converter power
Figure BDA00023295000800001618
At this time, the surplus power of the ac sub-network is scheduled to the dc sub-network to supplement the missing power of the dc sub-network, and the battery is charged.
S590, if
Figure BDA00023295000800001619
And is
Figure BDA00023295000800001620
The power of the bidirectional DC/DC converter and the power of the second converter are both set to zero, controlling the first ac power supply to supplement the missing power of the DC sub-network, and controlling the second ac power supply to supplement the missing power of the ac sub-network.
Wherein the central control unit is provided with a bidirectional DC/DC converter
Figure BDA00023295000800001621
Setting the second converter power
Figure BDA0002329500080000171
At the moment, the missing power of the direct current sub-network is balanced by the first large power grid, and the missing power of the alternating current sub-network is balanced by the second large power grid.
In one embodiment, if the microgrid is in an off-grid mode, adjusting the operating modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the operating mode of the microgrid comprises:
controlling the second converter to be in a constant-frequency and constant-voltage working mode to provide alternating-current voltage with stable frequency for the alternating-current sub-network; controlling the bidirectional DC/DC converter to be in a voltage stabilization mode so as to maintain the voltage stability of the direct current bus; and controlling the first converter to be in a power control mode so as to allocate the power of the direct current sub-network, the alternating current sub-network and the battery through the first converter.
Fig. 6 is a flowchart of a method for controlling the microgrid system when the microgrid system is in an off-grid mode, and under this condition, the central control unit controls the dc bus to keep the voltage stable by adjusting the operating power of the first converter. Under this operating condition, the microgrid control method specifically comprises:
and S610, acquiring the charge state of the battery.
And S620, judging whether the SoC value of the battery is in a normal threshold range, and if the SOC value of the battery is in the normal threshold range, entering the step S650.
If the output power of the distributed power supply on the alternating current side is increased and the output power of the second converter is smaller than the set minimum working power, the first converter dispatches part of the power of the alternating current side to the direct current side so as to improve the utilization efficiency of distributed energy and prevent the power reduction operation of the distributed power supply from being executed for keeping the frequency and the voltage of an alternating current sub-network stable.
S630, judging whether the SoC value of the battery exceeds an upper limit threshold value or not, and if the SOC value of the battery exceeds the upper limit threshold value, on one hand, the central control unit sets the power of the first converter
Figure BDA0002329500080000172
And on the other hand, the central control unit is respectively communicated with the local controllers of the direct current power generation device and the alternating current power generation device, so that the power output of the direct current power generation device and the power output of the direct current power generation device are reduced, and in the process, power interaction is not performed between the alternating current sub-network and the direct current sub-network.
And S640, judging whether the SoC value of the battery is lower than a lower limit threshold, if the state of charge of the battery is lower than the lower limit threshold, cutting off part of the direct current controllable load and/or the alternating current controllable load, reducing the power consumption of the microgrid, and then entering the step S650.
And meanwhile, when the output of the second converter is smaller than the set minimum working power, the first converter dispatches part of the power of the alternating current side to the direct current side.
S650, adjusting the power of the first converter according to the current output power of the second converter, wherein if the current output net power of the second converter is smaller than the minimum working power, the central control unit sets the power of the first converter
Figure BDA0002329500080000181
Part of power of the alternating current sub-network is dispatched to the direct current sub-network, so that the utilization efficiency of the distributed energy is improved; if the current output net power of the second converter is more than or equal to the minimum working power of the second converter
Figure BDA0002329500080000182
The central control unit sets the power of the first converter
Figure BDA0002329500080000183
Figure BDA0002329500080000184
The minimum working power of the second converter is used for ensuring the stable frequency of the voltage on the alternating current side.
According to the technical scheme of the embodiment, the central control unit adjusts the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the residual electric quantity information of the battery and the working mode of the microgrid, can control the energy flow of the battery, the direct current sub-network and the alternating current sub-network, can manage the energy of the microgrid, provides effective power support for the alternating current sub-network and the direct current sub-network, improves the utilization efficiency and the local consumption efficiency of distributed renewable energy sources, and ensures stable operation of a system.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, but may include more general equivalent embodiments without departing from the inventive concept, and the scope of the present invention is determined by the scope of the appended claims.

Claims (13)

1. A hybrid microgrid system, comprising: a central control unit, a bidirectional DC/AC converter, a bidirectional DC/DC converter, a battery, a DC sub-network and an AC sub-network, wherein the central control unit is respectively connected with the bidirectional DC/AC converter and the bidirectional DC/DC converter in a communication way,
the direct current side of the bidirectional DC/AC converter is connected with a first direct current bus, and the battery is connected with the first direct current bus through the bidirectional DC/DC converter; the direct-current sub-network is connected with a second direct-current bus, the second direct-current bus is connected with the first direct-current bus, and the direct-current sub-network at least comprises a direct-current power generation device and a direct-current controllable load;
the alternating current side of the bidirectional DC/AC converter is connected with an external network and an alternating current bus, and the alternating current sub-network is connected with the alternating current bus; the alternating current sub-network at least comprises an alternating current power generation device and an alternating current controllable load.
2. The hybrid microgrid system of claim 1, wherein the bidirectional DC/AC converter comprises a first converter and a second converter arranged in series, the DC side of the first converter and the DC side of the second converter being connected to the first DC bus; the control port of the first converter and the control port of the second converter are respectively connected with the central control unit; the alternating current side of the second converter is connected with the alternating current bus, the alternating current feeder of the first converter is connected with a first alternating current power supply through a first controllable switch, and the alternating current feeder of the second converter is connected with a second alternating current power supply through a second controllable switch;
the alternating current feeder of the first converter is connected with the alternating current feeder of the second converter through a connecting line, a third controllable switch is arranged on the connecting line, and the control end of each controllable switch is connected to the central control unit.
3. The hybrid microgrid system of claim 1, wherein the alternating current power generation apparatus, the alternating current controllable load, the direct current power generation apparatus and the direct current controllable load are each provided with a local controller, each of the local controllers being communicatively connected with the central control unit;
the battery is provided with a battery controller, and the battery is in communication connection with the central control unit through the battery controller;
and the feeder port of the second direct current bus and the feeder port of the alternating current bus are respectively in communication connection with the central control unit.
4. The hybrid microgrid system of claim 1, wherein the direct current power generation device comprises a photovoltaic system and a first DC/DC converter, the photovoltaic system is connected with the second direct current bus through the first DC/DC converter; the direct-current controllable load is connected with the second direct-current bus through a second DC/DC converter;
the alternating current power generation device comprises a wind power system and an AC/DC/AC converter, wherein the wind power system is connected with the alternating current bus through the AC/DC/AC converter.
5. A control method for a hybrid microgrid system, applied to the hybrid microgrid system of claim 1, comprising:
acquiring the state of charge of a battery;
and adjusting the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the working mode of the microgrid.
6. The control method according to claim 5, wherein the bidirectional DC/AC converter comprises a first converter and a second converter arranged in series, and a DC side of the first converter and a DC side of the second converter are connected with the first DC bus; the control port of the first converter and the control port of the second converter are respectively connected with the central control unit; the alternating current side of the second converter is connected with the alternating current bus, the alternating current feeder of the first converter is connected with a first alternating current power supply through a first controllable switch, and the alternating current feeder of the second converter is connected with a second alternating current power supply through a second controllable switch;
the alternating current feeder of the first converter is connected with the alternating current feeder of the second converter through a connecting line, a third controllable switch is arranged on the connecting line, and the control end of each controllable switch is connected to the central control unit;
before adjusting the operating modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the operating mode of the microgrid, the method further comprises the following steps:
if the fault of the external grid is detected, controlling the first controllable switch and the second controllable switch to be disconnected, and controlling the third controllable switch to be connected, so that the microgrid is in an off-grid mode;
and if the external grid has no fault, controlling the first controllable switch and the second controllable switch to be connected, and controlling the third controllable switch to be disconnected, so that the microgrid is in a grid-connected mode.
7. The method of claim 6, wherein if the microgrid is in a grid-connected mode, the adjusting the operating modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the operating mode of the microgrid comprises:
if the state of charge of the battery is in a normal threshold range, controlling the first converter and the second converter to be in a power control mode, and controlling the bidirectional DC/DC converter to be in a voltage stabilization mode;
and if the state of charge of the battery is lower than a lower limit threshold or exceeds an upper limit threshold, controlling the first converter to be in a voltage stabilization mode, and controlling the second converter and the bidirectional DC/DC converter to be in a power control mode.
8. The control method of claim 7, wherein after said adjusting the operating mode of said bidirectional DC/AC converter and said bidirectional DC/DC converter, said method further comprises:
obtaining the DC elementNet power of net
Figure FDA0002329500070000031
And net power of said AC sub-network
Figure FDA0002329500070000032
The net power of the direct current sub-network is obtained by low-pass filtering the current power of the direct current sub-network, and the net power of the alternating current sub-network is obtained by low-pass filtering the current power of the alternating current sub-network;
and adjusting the power distribution of the direct current sub-network, the alternating current sub-network and the battery according to the working modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter, and the net power of the direct current sub-network and the net power of the alternating current sub-network so as to control the micro-grid to keep the energy supply and demand balance.
9. The method of claim 8, wherein if the state of charge of the battery is within a normal threshold range, the adjusting the power distribution of the dc sub-network, the ac sub-network, and the battery to control the microgrid to maintain energy supply and demand balance comprises:
if it is as described
Figure FDA0002329500070000041
And said
Figure FDA0002329500070000042
Setting the power of the first converter to zero and the power of the second converter to zero
Figure FDA0002329500070000043
Controlling the surplus power of the alternating current sub-network to charge the battery;
if it is as described
Figure FDA0002329500070000044
And said
Figure FDA0002329500070000045
Setting the power of the first converter to zero and the power of the second converter to zero
Figure FDA0002329500070000046
The surplus power of the direct current sub-network is dispatched to the alternating current sub-network to make up for the missing power of the alternating current sub-network;
if it is as described
Figure FDA0002329500070000047
And said
Figure FDA0002329500070000048
Setting the power of the first converter to zero and the power of the second converter to zero
Figure FDA0002329500070000049
The surplus power of the alternating current sub-network is dispatched to the direct current sub-network to make up for the missing power of the direct current sub-network;
if it is as described
Figure FDA00023295000700000410
And said
Figure FDA00023295000700000411
And setting the power of the first converter and the power of the second converter to be zero, and controlling the alternating current sub-network and the direct current sub-network not to generate power interaction.
10. The method of claim 8, wherein if the state of charge of the battery exceeds an upper threshold, the adjusting the power distribution of the dc sub-network, the ac sub-network, and the battery to control the microgrid to maintain energy supply and demand balance comprises:
if it is as described
Figure FDA00023295000700000412
And said
Figure FDA00023295000700000413
Setting the power of the second converter and the power of the bidirectional DC/DC converter to be zero so as to dispatch the surplus power of the direct current sub-network to a first alternating current power supply and dispatch the surplus power of the alternating current sub-network to a second alternating current power supply;
if it is as described
Figure FDA0002329500070000051
And said
Figure FDA0002329500070000052
Setting the power of the second converter to
Figure FDA0002329500070000053
Setting the power of the bidirectional DC/DC converter to
Figure FDA0002329500070000054
The surplus power of the direct current sub-network is dispatched to the alternating current sub-network, and the difference power is supplemented through the battery;
if it is as described
Figure FDA0002329500070000055
And said
Figure FDA0002329500070000056
Setting the power of the second converter to
Figure FDA0002329500070000057
Setting the power of the bidirectional DC/DC converter to
Figure FDA0002329500070000058
The surplus power of the alternating current sub-network is dispatched to the direct current sub-network, and the difference power is supplemented through the battery;
if it is as described
Figure FDA0002329500070000059
And said
Figure FDA00023295000700000510
Setting the power of the bidirectional DC/DC converter to
Figure FDA00023295000700000511
Setting the power of the second converter to zero to supplement the missing power of the dc sub-network by the battery and to supplement the missing power of the ac sub-network by the second ac power source.
11. The method of claim 8, wherein if the state of charge of the battery is below a lower threshold, the adjusting the power distribution of the dc sub-network, the ac sub-network, and the battery to control the microgrid to maintain energy supply and demand balance comprises:
if it is as described
Figure FDA00023295000700000512
And said
Figure FDA00023295000700000513
Setting the power of the second converter to
Figure FDA00023295000700000514
Setting the power of the bidirectional DC/DC converter to
Figure FDA00023295000700000515
Controlling the surplus power of the alternating current sub-network and the direct current sub-network to charge the battery;
if it is as described
Figure FDA00023295000700000516
And said
Figure FDA00023295000700000517
Setting the power of the second converter to zero and the power of the bidirectional DC/DC converter to zero
Figure FDA00023295000700000518
Controlling the surplus power of the direct current sub-network to charge the battery;
if it is as described
Figure FDA00023295000700000519
And said
Figure FDA00023295000700000520
Setting the power of the second converter to
Figure FDA00023295000700000521
Setting the power of the bidirectional DC/DC converter to
Figure FDA0002329500070000061
The surplus power of the alternating current sub-network is controlled to preferentially supplement the missing power of the direct current sub-network, and the residual power is used for charging the battery;
if it is as described
Figure FDA0002329500070000062
And said
Figure FDA0002329500070000063
Setting both the power of the bidirectional DC/DC converter and the power of the second converter to zero, controlling the first ac power source to supplement the missing power of the DC sub-network, and controlling the second ac power source to supplement the second ac power sourceThe missing power of the ac sub-network.
12. The method of claim 6, wherein if the microgrid is in an off-grid mode, the adjusting the operating modes of the bidirectional DC/AC converter and the bidirectional DC/DC converter according to the state of charge of the battery and the operating mode of the microgrid comprises:
and controlling the second converter to be in a constant-frequency and constant-voltage working mode, controlling the first converter to be in a power control mode, and controlling the bidirectional DC/DC converter to be in a voltage stabilizing mode.
13. The control method of claim 12, wherein after said adjusting the operating mode of said bidirectional DC/AC converter and said bidirectional DC/DC converter, said method further comprises:
if the state of charge of the battery is in a normal threshold range, adjusting the power of the first converter according to the current output power of the second converter, wherein if the current output net power of the second converter is smaller than the minimum working power, the power of the first converter is set to be the power of the first converter
Figure FDA0002329500070000064
To schedule a portion of the power of the ac sub-network to the dc sub-network; otherwise, setting the power of the first converter to be zero; the above-mentioned
Figure FDA0002329500070000065
The minimum working power of the second converter;
if the state of charge of the battery exceeds an upper limit threshold, controlling the direct current power generation device and the alternating current power generation device to reduce power output, and not performing power interaction between the alternating current sub-network and the direct current sub-network;
if the state of charge of the battery is lower than the lower limit threshold, cutting off part of direct current controllable load and/or alternating current controllable load, reducing the power consumption of the micro-gridAdjusting the power of the first converter according to the current output power of the second converter, wherein if the current output net power of the second converter is smaller than the minimum working power, the power of the first converter is set to be the minimum working power
Figure FDA0002329500070000071
To schedule a portion of the power of the ac sub-network to the dc sub-network; otherwise, the power of the first converter is set to be zero.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113839426A (en) * 2021-09-02 2021-12-24 山东大学 Electric energy supply system of zero-carbon-emission building and energy management method thereof
WO2023185196A1 (en) * 2022-04-02 2023-10-05 南京南瑞继保电气有限公司 Energy storage system structure for ac power grid interconnection and control method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103078325A (en) * 2012-12-31 2013-05-01 河北省电力公司电力科学研究院 Alternating current and direct current mixed micro power grid system and control method thereof
CN103280844A (en) * 2013-05-14 2013-09-04 国家电网公司 Alternating/direct current hybrid multi-level micro grid system
CN103647274A (en) * 2013-11-26 2014-03-19 中国西电电气股份有限公司 Micro-grid system being capable of grid-connected and off-grid operation, and energy control method
CN104319816A (en) * 2014-11-17 2015-01-28 合肥工业大学 Optical storage alternating current and direct current hybrid micro-grid system and control method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103078325A (en) * 2012-12-31 2013-05-01 河北省电力公司电力科学研究院 Alternating current and direct current mixed micro power grid system and control method thereof
CN103280844A (en) * 2013-05-14 2013-09-04 国家电网公司 Alternating/direct current hybrid multi-level micro grid system
CN103647274A (en) * 2013-11-26 2014-03-19 中国西电电气股份有限公司 Micro-grid system being capable of grid-connected and off-grid operation, and energy control method
CN104319816A (en) * 2014-11-17 2015-01-28 合肥工业大学 Optical storage alternating current and direct current hybrid micro-grid system and control method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113839426A (en) * 2021-09-02 2021-12-24 山东大学 Electric energy supply system of zero-carbon-emission building and energy management method thereof
WO2023185196A1 (en) * 2022-04-02 2023-10-05 南京南瑞继保电气有限公司 Energy storage system structure for ac power grid interconnection and control method
GB2627383A (en) * 2022-04-02 2024-08-21 Nr Electric Co Ltd Energy storage system structure for AC power grid interconnection and control method

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