Multi-source energy storage system and control method thereof

Abstract

The invention discloses a multi-source energy storage system and a control method thereof, and the system comprises a DC bus which is used for transmitting and distributing DC electric energy; the commercial power side alternating current power supply is connected to the direct current bus through a commercial power side control unit; the clean energy power generation unit is connected to the direct current bus through a clean energy control unit; the battery cluster is connected to the direct-current bus through a high-voltage distribution box and is used for storing and releasing electric energy; the off-grid control unit is connected between the direct current bus and a load and is used for converting direct current of the direct current bus into alternating current and supplying power to the load; and the energy management unit controls the work of the commercial power side control unit, the clean energy control unit, the high-voltage distribution box and the off-grid control unit according to the output power of the clean energy power generation unit, the state of charge (SOC) of the battery cluster and the access state of the commercial power side AC power supply. And the clean energy power generation unit, the battery cluster and / or the commercial power side AC power supply are switched and controlled to supply power.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and more particularly to a multi-source energy storage system and a control method thereof. Background Art

[0002] With the continuous advancement of oil exploration and production, the reliability and stability of oilfield power supply systems have become critical issues. The stability of the power supply system is not only related to the normal operation of oilfield production, but also to the safety and environmental protection of oilfield facilities. Currently, to maintain the stability of oilfield power supply systems, a single power supply is usually used. However, as the power consumption of loads increases during production, this single power supply mode can no longer effectively meet the actual power demand of the loads. Summary of the Invention

[0003] The present invention provides a multi-source energy storage system and a control method thereof, so as to solve the technical problem that the existing single power supply mode cannot well meet the actual power demand of the load.

[0004] To solve the above technical problems, according to one aspect of the present invention, the present invention provides a multi-source energy storage system, comprising:

[0005] DC bus, used to transmit and distribute DC power;

[0006] A mains-side AC power supply is connected to the DC bus via a mains-side control unit, wherein the mains-side control unit is configured to convert the AC power of the mains-side AC power supply into DC power;

[0007] A clean energy power generation unit is connected to the DC bus via a clean energy control unit, wherein the clean energy control unit is used to control the output of the clean energy power generation unit;

[0008] a battery cluster connected to the DC bus via a high-voltage distribution box for storing and releasing electrical energy;

[0009] an off-grid control unit, connected between the DC bus and the load, for converting the DC power of the DC bus into AC power and supplying power to the load;

[0010] The energy management unit controls the operation of the mains-side control unit, the clean energy control unit, the high-voltage distribution box and the off-grid control unit according to the output power of the clean energy power generation unit, the state of charge (SOC) of the battery cluster and the access status of the mains-side AC power supply, so as to switch and control the power supply of the clean energy power generation unit, the battery cluster and / or the mains-side AC power supply.

[0011] Its further technical solution is: the multi-source energy storage system further includes a switch, the AC power supply on the mains side includes the mains power and the backup AC power supply; wherein,

[0012] The input side of the switch is connected to the mains power and the backup AC power supply, and the output side of the switch is connected to the mains power side control unit, for selecting the mains power or the backup AC power supply to be connected to the mains power side control unit;

[0013] The energy management unit is also electrically connected to the switch, and is used to control the backup AC power supply or the mains power supply according to the output power of the clean energy power generation unit, the state of charge (SOC) of the battery cluster, and the state of the switch.

[0014] Its further technical solution is: the clean energy power generation unit includes at least one photovoltaic power generation unit, and the clean energy control unit includes at least one photovoltaic power generation control unit; wherein, the output end of the photovoltaic power generation unit is connected to a DC bus through the photovoltaic power generation control unit to supply power to the load through the DC bus and / or charge the battery cluster.

[0015] Its further technical solution is: the clean energy power generation unit also includes at least one wind power generation unit, and the clean energy control unit includes at least one wind power generation control unit; wherein, the output end of the wind power generation unit is connected to the DC bus through the wind power generation control unit to supply power to the load through the DC bus and / or charge the battery cluster.

[0016] Its further technical solution is: the mains side control unit and the off-grid control unit are both energy storage converters, and the mains side control unit is connected to the output end of the mains side AC power supply through an AC bus, and a surge protector is also connected to the AC bus.

[0017] To solve the above technical problems, according to another aspect of the present invention, the present invention further provides a control method for a multi-source energy storage system, comprising:

[0018] Determine the output power of the clean energy generation unit and the load power of the multi-source energy storage system;

[0019] Determine whether the output power of the clean energy power generation unit is greater than or equal to the load power;

[0020] If yes, control the clean energy power generation unit to supply power to the load and store the remaining power in the battery cluster, and detect the state of charge (SOC) of the battery cluster;

[0021] controlling the output of the clean energy power generation unit according to the state of charge (SOC) of the battery cluster;

[0022] If the output power of the clean energy power generation unit is less than the load power, the clean energy power generation unit, the battery cluster and / or the AC power supply on the mains side are controlled to supply power according to the state of charge (SOC) of the battery cluster and the access status of the AC power supply on the mains side.

[0023] A further technical solution is: controlling the output of the clean energy power generation unit according to the state of charge (SOC) of the battery cluster includes:

[0024] Determining whether the state of charge (SOC) of the battery cluster is greater than or equal to a first upper limit threshold;

[0025] If so, the clean energy power generation unit is controlled to limit the output of the clean energy power generation unit, and the battery cluster is controlled to supply power, entering a battery main power supply mode.

[0026] A further technical solution thereof is: after determining whether the state of charge (SOC) of the battery cluster is greater than or equal to a first upper limit threshold, further comprising: if not, maintaining the maximum output of the clean energy power generation unit;

[0027] and / or,

[0028] After entering the battery main power supply mode, the method further includes: detecting whether the state of charge (SOC) of the battery cluster is less than a second upper limit threshold; if so, canceling the output restriction of the clean energy power generation unit; if not, maintaining the current state.

[0029] A further technical solution is: controlling the power supply of the clean energy power generation unit, the battery cluster and / or the AC power supply on the mains side according to the state of charge (SOC) of the battery cluster and the access status of the AC power supply on the mains side includes:

[0030] Control the clean energy power generation unit and battery cluster to jointly supply power;

[0031] Detecting and determining whether the state of charge (SOC) of the battery cluster is less than or equal to a first lower limit threshold;

[0032] If not, maintain the joint power supply of the clean energy power generation unit and the battery cluster; if so, detect the access status of the AC power supply on the mains side. If the mains is connected, start the mains power supply mode so that the mains power can power the load and charge the battery cluster;

[0033] Check whether the state of charge (SOC) of the battery cluster is greater than or equal to the grid-connected SOC upper limit. If so, re-execute the step of determining whether the output power of the clean energy power generation unit is greater than or equal to the load power. If not, maintain the mains power supply mode.

[0034] A further technical solution thereof is: after detecting the access status of the AC power supply on the mains side, the method further comprises:

[0035] If the mains power is not connected, or if the mains power connection is abnormal, the backup AC power supply on the mains side will be started;

[0036] If the backup AC power supply is successfully started, the system enters the backup AC power supply mode, so that the backup AC power supply can supply power to the load and charge the battery cluster.

[0037] Detecting whether the state of charge (SOC) of the battery cluster at this time is greater than or equal to the grid-connected SOC upper limit; if so, re-execute the step of determining whether the output power of the clean energy power generation unit is greater than or equal to the load power; if not, maintain the backup AC power supply mode;

[0038] If the backup AC power fails to start, the clean energy power generation unit and the battery cluster are maintained to provide power, and the state of charge (SOC) of the battery cluster is detected to be less than or equal to the second lower threshold.

[0039] If so, the power supply connection to the load is cut off, and the clean energy power generation unit charges the battery cluster until the state of charge (SOC) of the battery cluster is greater than or equal to the restoration preset threshold, and the power supply to the load is restored.

[0040] Compared with the prior art, the multi-source energy storage system of the present invention is provided with a mains-side AC power supply, a battery cluster and a clean energy power generation unit. The mains-side AC power supply, the battery cluster and the clean energy power generation unit are all connected to a DC bus for transmitting and distributing DC power. The DC bus is connected to a load through an off-grid control unit. The output power of the clean energy power generation unit, the state of charge SOC of the battery cluster and the access status of the mains-side AC power supply are obtained through the energy management unit, and the mains-side control unit, the clean energy power generation unit and the battery cluster are controlled according to the output power of the clean energy power generation unit, the state of charge SOC of the battery cluster and the access status of the mains-side AC power supply. The control unit, high-voltage distribution box and off-grid control unit work to switch and control the clean energy power generation unit, battery cluster and / or mains power supply. It can be seen that the multi-source energy storage system of the present invention is a multi-source power supply mode when supplying power. The power supply can be switched and controlled according to the output power of the clean energy power generation unit, the charge state SOC of the battery cluster and the access status of the AC power supply on the mains side. That is, the power supply can be switched according to the status of each power supply source, which can well meet the actual power demand of the load. At the same time, in large-scale power supply sites (such as oil field mining sites), it can also avoid power supply problems caused by failure or abnormality of a single power supply, and maintain the stability and reliability of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural diagram of a specific embodiment of the multi-source energy storage system of the present invention.

[0042] Figure 2 It is a flow chart of the control method of the multi-source energy storage system of the present invention.

[0043] Figure 3 It is a sub-flow diagram of the control method of the multi-source energy storage system of the present invention.

[0044] Figure 4 It is another sub-flow diagram of the control method of the multi-source energy storage system of the present invention. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to more clearly understand the objectives, technical solutions and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0046] Reference Figure 1 , Figure 1The structure diagram of a specific embodiment of the multi-source energy storage system of the present invention is shown in the accompanying drawings. In the embodiment shown in the accompanying drawings, the multi-source energy storage system includes a mains-side control unit 10, a DC bus 30, a battery cluster 20, a clean energy power generation unit 40, an off-grid control unit 50, and an energy management unit (not shown in the figure); wherein the DC bus 30 is used to transmit and distribute DC power, the mains-side AC power supply is connected to the DC bus 30 through the mains-side control unit 10, and the mains-side control unit 10 is used to convert the mains-side AC power into DC power; the clean energy power generation unit 40 is connected to the DC bus 30 through a clean energy control unit, and the clean energy control unit is used to control the output of the clean energy power generation unit 40 ; The battery cluster 20 is connected to the DC bus 30 through a high-voltage distribution box 21 for storing and releasing electrical energy; the off-grid control unit 50 is connected between the DC bus 30 and the load, for converting the DC power of the DC bus 30 into AC power and supplying power to the load; the energy management unit controls the operation of the mains-side control unit 10, the clean energy control unit, the high-voltage distribution box 21 and the off-grid control unit 50 according to the output power of the clean energy power generation unit 40, the state of charge SOC of the battery cluster 20 and the access status of the mains-side AC power supply, so as to switch and control the power supply of the clean energy power generation unit 40, the battery cluster 20 and / or the mains-side AC power supply. Preferably, in this embodiment, the mains-side control unit 10 and the off-grid control unit 50 are both energy storage converters. The mains-side control unit 10 is connected to the output end of the mains-side AC power supply, mainly converting the AC power output by the mains-side AC power supply into DC power, and auxiliaryly supplying the load through the DC bus 30, and charging the battery cluster 20; while the off-grid control unit 50 is dedicated to the off-grid inverter function, maintaining the load-side AC grid and supplying power. Based on the above design, the multi-source energy storage system of the present invention can be powered by the mains-side AC power supply, the clean energy power generation unit 40 and the battery cluster 20. When powering, it is in a multi-source power supply mode, that is, the power supply can be switched according to the status of each power supply. Specifically, the power supply can be switched and controlled according to the output power of the clean energy power generation unit 40, the state of charge SOC of the battery cluster 20 and the access status of the mains-side AC power supply, which can well meet the actual power demand of the load. At the same time, in large-scale power supply sites (such as oil field mining sites), it can also avoid power supply problems caused by failure or abnormality of a single power supply, and maintain the stability and reliability of power supply.

[0047] In some embodiments, the multi-source energy storage system further includes a switch S1, and the mains-side AC power supply includes a mains power supply and a backup AC power supply; wherein the input side of the switch S1 is connected to the mains power supply and the backup AC power supply, and the output side of the switch S1 is connected to the mains-side control unit 10 via an AC bus, for selecting the mains power supply or the backup AC power supply to be connected to the mains-side control unit 10; the energy management unit is also electrically connected to the switch S1, for controlling the backup AC power supply or the mains power supply according to the output power of the clean energy power generation unit 40, the state of charge (SOC) of the battery cluster 20, and the state of the switch S1. Preferably, the switch S1 is an ATS automatic switching switch, the backup AC power supply can be a diesel generator set, and the AC bus is also connected to a surge protector 60 for protecting system equipment from overvoltage surges. In this embodiment, under normal circumstances, the clean energy power generation unit 40 and the battery cluster 20 are prioritized for power supply. When the clean energy power generation unit 40 generates electricity and the battery cluster 20 stores insufficient energy, the mains power supply and the diesel generator set are activated as backup power sources to charge the battery cluster 20 and ensure power supply to the load. Based on the above design, the switch S1 is used to automatically switch between the mains and the diesel generator set and connect them to the AC bus.

[0048] In some embodiments, the clean energy power generation unit 40 includes two photovoltaic power generation units 41, and the clean energy control unit includes two photovoltaic power generation control units 411. The photovoltaic power generation control unit 411 can operate in MPPT mode; wherein the output end of the photovoltaic power generation unit 41 is connected to the DC bus 30 through the photovoltaic power generation control unit 411 to supply power to the load through the DC bus 30 and / or charge the battery cluster 20.

[0049] Furthermore, in some other embodiments, the clean energy power generation unit 40 may also include a wind power generation unit, and the clean energy control unit includes a wind power generation control unit, which may be an inverter; wherein the output end of the wind power generation unit may be connected to the DC bus 30 through the wind power generation control unit to supply power to the load through the DC bus 30 and / or charge the battery cluster 20.

[0050] It can be understood that in the present invention, the energy management unit is the control unit of the multi-source energy storage system, and a programmable logic controller (PLC) can be used as the main controller. The energy management unit can monitor in real time the load power, the real-time output power of the clean energy power generation unit 40 (photovoltaic power generation unit 41 and / or wind power generation unit), the access status of the AC power supply on the mains side, and the state of charge (SOC) of the battery cluster 20 and other status parameters.

[0051] As can be seen from the above, the multi-source energy storage system of the present invention can be powered by the AC power supply on the mains side, the clean energy power generation unit 40 and the battery cluster 20. When powering, it is a multi-source power supply mode, that is, the power supply is switched and controlled according to the output power of the clean energy power generation unit 40, the state of charge (SOC) of the battery cluster 20 and the access status of the AC power supply on the mains side. It can well meet the actual power demand of the load. At the same time, it can also avoid power supply problems caused by failure or abnormality of a single power supply in large-scale power supply sites (such as oil field production sites), and maintain the stability and reliability of power supply.

[0052] like Figure 2 As shown, Figure 2 The control method of the multi-source energy storage system of the present invention can be applied to the multi-source energy storage system described in the above embodiment and is executed by the energy management unit. In the embodiment shown in the accompanying drawings, the control method of the multi-source energy storage system includes the following steps:

[0053] S110: Determine the output power of the clean energy power generation unit and the load power of the multi-source energy storage system.

[0054] In the present invention, the multi-source energy storage system is initially set to operate in off-grid mode by default, operating independently of the public power grid, and is preferentially powered by clean energy power generation units and / or battery clusters. When the energy storage capacity of the clean energy power generation units and battery clusters is insufficient, the off-grid mode is exited, and the AC power supply on the mains side is started as a backup power source to charge the battery cluster and ensure power supply to the load.

[0055] In this step, when the clean energy power generation unit only includes a photovoltaic power generation unit, the output power of the photovoltaic power generation unit is detected.

[0056] S120 , determine whether the output power of the clean energy power generation unit is greater than or equal to the load power; if so, execute steps S130 - S140 ; ​​if not, execute step S150 .

[0057] S130 , controlling the clean energy power generation unit to supply power to the load and storing the remaining power in the battery cluster, and detecting the state of charge (SOC) of the battery cluster.

[0058] In this step, the photovoltaic power generation unit discharges to supply the load, and the excess electricity is absorbed and stored by the battery cluster.

[0059] S140 : Control the output of the clean energy power generation unit according to the state of charge (SOC) of the battery cluster.

[0060] like Figure 3 As shown, step S140 specifically includes the following steps S141-S143:

[0061] S141 , determine whether the state of charge (SOC) of the battery cluster is greater than or equal to a first upper threshold; if so, execute steps S142 - S143 ; if not, execute step S144 .

[0062] In this step, the first upper limit threshold is 90% of the battery capacity, that is, 90% of the fully charged state of the battery cluster. When the state of charge (SOC) of the battery cluster reaches 90% of the battery capacity, the output of the photovoltaic power generation unit is limited, and the load is mainly supplied by the discharge of the battery cluster. When the state of charge (SOC) of the battery cluster does not reach 90% of the battery capacity, the maximum output of the photovoltaic power generation unit is maintained.

[0063] S142: Control the clean energy power generation unit to limit the output of the clean energy power generation unit, control the battery cluster to supply power, and enter the battery main power supply mode.

[0064] In this step, the output of the photovoltaic power generation unit is limited by controlling the photovoltaic power generation control unit. At the same time, the battery cluster discharges to the DC bus through the high-voltage distribution box, entering the battery main power supply mode.

[0065] S143: After entering the battery main power supply mode, detect whether the state of charge (SOC) of the battery cluster is less than a second upper limit threshold. If so, cancel the output restriction of the clean energy power generation unit; if not, maintain the current state.

[0066] In this step, the second upper limit threshold is 80% of the battery capacity, that is, 80% of the fully charged state of the battery cluster. When entering the battery main power supply mode, when the state of charge (SOC) of the battery cluster drops below 80% of the battery capacity, the output restriction of the photovoltaic power generation unit is released, and the photovoltaic power generation unit is mainly used to discharge to supply the load.

[0067] S144. Maintain the maximum output of the clean energy power generation unit.

[0068] S150 : Controlling the clean energy power generation unit, the battery cluster and / or the AC power supply on the mains side to supply power according to the state of charge (SOC) of the battery cluster and the access status of the AC power supply on the mains side.

[0069] like Figure 4 As shown, step S150 specifically includes the following steps S1500-S1509:

[0070] S1500 controls the clean energy power generation unit and the battery cluster to jointly supply power.

[0071] In this step, when the output power of the photovoltaic power generation unit is less than the load power, the output power of the photovoltaic power generation unit is limited, and the photovoltaic and battery combined power supply mode is entered. When applied to the multi-source energy storage system of the above embodiment, the energy management unit controls the photovoltaic power generation control unit and the high-voltage distribution box so that the battery cluster discharges to the DC bus through the high-voltage distribution box, and together with the photovoltaic power generation unit, supplies power to the load, thus entering the photovoltaic and battery combined power supply mode.

[0072] S1501. Detect and determine whether the state of charge (SOC) of the battery cluster is less than or equal to a first lower threshold; if not, maintain the clean energy power generation unit and the battery cluster jointly supplying power; if so, execute steps S1502-S1509.

[0073] In this step, the first lower threshold is 30% of the battery capacity, that is, 30% of the fully charged state of the battery cluster. After entering the photovoltaic and battery combined power supply mode, when the real-time detected state of charge (SOC) of the battery cluster drops to 30%, it indicates that the energy storage capacity of the clean energy power generation unit and the battery cluster is insufficient. The multi-source energy storage system exits the off-grid mode, and the AC power supply on the mains side will start as a backup power supply.

[0074] S1502. Detect the AC power connection status on the mains side; if the mains is connected normally, execute steps S1503-S1504; if the mains is not connected or the connection is abnormal, execute steps S1505-S1507.

[0075] In this embodiment, the access status of the AC power supply on the mains side can be obtained by detecting the status of the ATS automatic switching switch. When the ATS automatic switching switch is offline, it means that the mains power is not connected. At this time, the backup AC power supply (such as a diesel generator set) is started, and when the ATS automatic switching switch is online, it is detected whether the mains power is normally connected.

[0076] In this step, if the mains power is connected normally, the system enters the mains power supply mode, supplies power to the load, and simultaneously charges the battery cluster. The state of charge (SOC) of the battery cluster is monitored in real time. When the SOC of the battery cluster is greater than or equal to the upper limit of the grid-connected SOC, the system returns to the off-grid mode and re-executes step S120. It is understood that the upper limit of the grid-connected SOC is the maximum allowable state of charge of the battery when connected to the grid.

[0077] S1503: Start the mains power supply mode so that the mains power supplies power to the load and charges the battery cluster.

[0078] S1504 , detecting whether the state of charge (SOC) of the battery cluster is greater than or equal to the upper limit of the grid-connected SOC. If so, re-execute step S120 ; if not, maintain the mains power supply mode.

[0079] In this step, when the state of charge (SOC) of the battery cluster reaches the grid-connected SOC upper limit, the energy management unit controls the mains-side control unit to shut down and stop drawing power from the mains-side AC power supply. The system returns to off-grid mode, with power supplied by the photovoltaic power generation unit and the battery cluster as the priority.

[0080] S1505. Start the backup AC power supply on the mains side; if the backup AC power supply starts successfully, execute steps S1506-S1507; if the backup AC power supply fails to start, execute steps S1508-S1509.

[0081] In the present invention, when the mains power is not connected or the connection is abnormal, the diesel generator set is started. If the startup is successful, the diesel generator set power supply mode is entered to supply power to the load and charge the battery cluster at the same time. If the startup fails, the photovoltaic and battery combined power supply mode is maintained, and the state of charge (SOC) of the battery cluster is detected in real time to see whether it is less than or equal to a second lower threshold. When it drops to the second lower threshold, the power supply to the load is cut off, and the battery cluster is charged preferentially through the photovoltaic power generation unit, so that the charge capacity of the battery cluster is not too low and damaged. When the state of charge (SOC) of the battery cluster rises to the preset recovery threshold, the off-grid control unit is controlled to restart and the power supply to the load is restored.

[0082] S1506: Enter the backup AC power supply mode, so that the backup AC power supply supplies power to the load and charges the battery cluster.

[0083] S1507 , detecting whether the state of charge (SOC) of the battery cluster is greater than or equal to the upper limit of the grid-connected SOC. If so, re-execute step S120 ; if not, maintain the backup AC power supply mode.

[0084] S1508: Maintain the joint power supply of the clean energy power generation unit and the battery cluster, and detect whether the state of charge (SOC) of the battery cluster is less than or equal to a second lower threshold.

[0085] In this step, the second lower threshold is 10% of the battery capacity, that is, 10% of the fully charged state of the battery cluster. When there is no mains power supply, the backup AC power supply fails to start, and the state of charge (SOC) of the battery cluster drops to 10% of the battery capacity, the energy management unit controls the off-grid control unit to shut down and disconnect the DC bus from the load to prevent the battery cluster from being damaged due to low charge.

[0086] S1509: If yes, cut off the power supply connection to the load, and the clean energy power generation unit charges the battery cluster until the state of charge (SOC) of the battery cluster is greater than or equal to the preset restoration threshold, and then resume power supply to the load.

[0087] In this step, the preset threshold is restored to 20% of the battery capacity, that is, 20% of the fully charged state of the battery cluster. When the state of charge (SOC) of the battery cluster rises to 20% of the battery capacity, the off-grid control unit is controlled to restart and resume power supply to the load.

[0088] In summary, the control method for a multi-source energy storage system of the present invention determines the operating mode of the multi-source energy storage system based on the output power of the clean energy generation unit and the load power. This determines whether the multi-source energy storage system is operating in an off-grid mode powered by the clean energy generation unit and / or battery cluster, or in a power supply mode in which the AC power supply on the mains side is activated as a backup power source to charge the battery cluster and ensure power supply to the load. In different operating modes, the control method also combines the battery cluster's state of charge (SOC) to switch and control the power supply of different power sources, thereby meeting the actual power demand of the load while ensuring the stability and reliability of the power supply.

[0089] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Those skilled in the art may make various equivalent changes and improvements based on the above embodiment. Any equivalent changes or modifications made within the scope of the claims shall fall within the scope of protection of the present invention.

Claims

1. A multi-source energy storage system, characterized in that: The multi-source energy storage system includes: DC bus, used to transmit and distribute DC power; A mains-side AC power supply is connected to the DC bus via a mains-side control unit, wherein the mains-side control unit is configured to convert the AC power of the mains-side AC power supply into DC power; A clean energy power generation unit is connected to the DC bus via a clean energy control unit, wherein the clean energy control unit is used to control the output of the clean energy power generation unit; a battery cluster connected to the DC bus via a high-voltage distribution box for storing and releasing electrical energy; an off-grid control unit, connected between the DC bus and the load, for converting the DC power of the DC bus into AC power and supplying power to the load; The energy management unit controls the operation of the mains-side control unit, the clean energy control unit, the high-voltage distribution box and the off-grid control unit according to the output power of the clean energy power generation unit, the state of charge (SOC) of the battery cluster and the access status of the mains-side AC power supply, so as to switch and control the power supply of the clean energy power generation unit, the battery cluster and / or the mains-side AC power supply.

2. The multi-source energy storage system according to claim 1, wherein: The multi-source energy storage system further includes a switch, and the AC power supply on the mains side includes the mains power and the backup AC power supply; wherein, The input side of the switch is connected to the mains power and the backup AC power supply, and the output side of the switch is connected to the mains power side control unit, for selecting the mains power or the backup AC power supply to be connected to the mains power side control unit; The energy management unit is also electrically connected to the switch, and is used to control the backup AC power supply or the mains power supply according to the output power of the clean energy power generation unit, the state of charge (SOC) of the battery cluster, and the state of the switch.

3. The multi-source energy storage system according to claim 1, wherein: The clean energy power generation unit includes at least one photovoltaic power generation unit, and the clean energy control unit includes at least one photovoltaic power generation control unit; wherein the output end of the photovoltaic power generation unit is connected to a DC bus through the photovoltaic power generation control unit to supply power to the load through the DC bus and / or charge the battery cluster.

4. The multi-source energy storage system according to claim 3, characterized in that: The clean energy power generation unit also includes at least one wind power generation unit, and the clean energy control unit includes at least one wind power generation control unit; wherein the output end of the wind power generation unit is connected to a DC bus through the wind power generation control unit to supply power to the load through the DC bus and / or charge the battery cluster.

5. The multi-source energy storage system according to claim 1, wherein: The mains side control unit and the off-grid control unit are both energy storage converters, and the mains side control unit is connected to the output end of the mains side AC power supply through an AC bus, and a surge protector is also connected to the AC bus.

6. A control method for a multi-source energy storage system, characterized in that: The control method of the multi-source energy storage system includes: Determine the output power of the clean energy generation unit and the load power of the multi-source energy storage system; Determine whether the output power of the clean energy power generation unit is greater than or equal to the load power; If yes, control the clean energy power generation unit to supply power to the load and store the remaining power in the battery cluster, and detect the state of charge (SOC) of the battery cluster; controlling the output of the clean energy power generation unit according to the state of charge (SOC) of the battery cluster; If the output power of the clean energy power generation unit is less than the load power, the clean energy power generation unit, the battery cluster and / or the AC power supply on the mains side are controlled to supply power according to the state of charge (SOC) of the battery cluster and the access status of the AC power supply on the mains side.

7. The control method of the multi-source energy storage system according to claim 6, characterized in that: The controlling the output of the clean energy power generation unit according to the state of charge (SOC) of the battery cluster includes: Determining whether the state of charge (SOC) of the battery cluster is greater than or equal to a first upper limit threshold; If so, the clean energy power generation unit is controlled to limit the output of the clean energy power generation unit, and the battery cluster is controlled to supply power, entering a battery main power supply mode.

8. The control method of the multi-source energy storage system according to claim 7, characterized in that: After determining whether the state of charge (SOC) of the battery cluster is greater than or equal to a first upper limit threshold, the method further includes: if not, maintaining the maximum output of the clean energy power generation unit; and / or, After entering the battery main power supply mode, the method further includes: detecting whether the state of charge (SOC) of the battery cluster is less than a second upper limit threshold; if so, canceling the output restriction of the clean energy power generation unit; if not, maintaining the current state.

9. The control method of the multi-source energy storage system according to claim 6, characterized in that: The controlling of the clean energy power generation unit, the battery cluster and / or the AC power supply on the mains side according to the state of charge (SOC) of the battery cluster and the access status of the AC power supply on the mains side includes: Control the clean energy power generation unit and battery cluster to jointly supply power; Detecting and determining whether the state of charge (SOC) of the battery cluster is less than or equal to a first lower limit threshold; If not, maintain the joint power supply of the clean energy power generation unit and the battery cluster; if so, detect the access status of the AC power supply on the mains side. If the mains is connected, start the mains power supply mode so that the mains power can power the load and charge the battery cluster; Check whether the state of charge (SOC) of the battery cluster is greater than or equal to the grid-connected SOC upper limit. If so, re-execute the step of determining whether the output power of the clean energy power generation unit is greater than or equal to the load power. If not, maintain the mains power supply mode.

10. The control method of the multi-source energy storage system according to claim 9, characterized in that: After detecting the access status of the AC power supply on the mains side, the method further includes: If the mains power is not connected, or if the mains power connection is abnormal, the backup AC power supply on the mains side will be started; If the backup AC power supply is successfully started, the system enters the backup AC power supply mode, so that the backup AC power supply can supply power to the load and charge the battery cluster. Detecting whether the state of charge (SOC) of the battery cluster at this time is greater than or equal to the grid-connected SOC upper limit; if so, re-execute the step of determining whether the output power of the clean energy power generation unit is greater than or equal to the load power; if not, maintain the backup AC power supply mode; If the backup AC power fails to start, the clean energy power generation unit and the battery cluster are maintained to provide power, and the state of charge (SOC) of the battery cluster is detected to be less than or equal to the second lower threshold. If so, the power supply connection to the load is cut off, and the clean energy power generation unit charges the battery cluster until the state of charge (SOC) of the battery cluster is greater than or equal to the restoration preset threshold, and the power supply to the load is restored.

Images