Control method and device of power supply system and power supply system

Abstract

The invention discloses a control method and device of a power supply system and the power supply system, and belongs to the technical field of power supply. The power supply system comprises energy storage equipment, a direct-current converter and a converter, one end of the direct-current converter is connected with the energy storage equipment, the other end of the direct-current converter is connected to a direct-current bus, one end of the converter is connected to the direct-current bus, and the other end of the converter is used for being connected with a power grid. Under the condition that the at least two power conversion circuits are connected in a first electric connection mode, the direct-current converter is controlled to output the electric energy of the energy storage equipment to the direct-current bus in response to the condition that the direct-current bus voltage is smaller than a first voltage threshold value; under the condition that the DC bus voltage is greater than or equal to the first voltage threshold and the converter is started, acquiring voltage information of one end of the converter connected with the DC bus; and based on the voltage information, adjusting an electric connection mode between at least two power conversion circuits in the DC converter, so that the DC output voltage is matched with the voltage of one end of the converter connected with the DC bus.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a control method and device for a power supply system, and a power supply system. Background Art

[0002] A DC bus-coupled photovoltaic storage system usually includes a DC converter. The system can operate at different DC bus voltage levels, generally divided into low voltage (500V-650V) and high voltage (1000V-1100V). Regardless of the voltage level, the DC converter coupled to the DC bus for energy storage charging and discharging must meet the corresponding voltage resistance requirements.

[0003] Currently, during the black start process of a photovoltaic storage system without grid input and sunlight, it is impossible to determine the DC bus voltage level that the DC converter needs to support. Therefore, a high-voltage DC converter is usually used to meet the voltage requirements of the high voltage level. However, the material cost of the components in the high-voltage DC converter is relatively high, which increases the cost of the photovoltaic storage system. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a control method, device, and power supply system for a power supply system. These control methods, devices, and power supply systems can reduce the withstand voltage requirements of power conversion circuits by adjusting the electrical connection between at least two power conversion circuits during a black start process, thereby reducing the cost of the DC converter and, consequently, the cost of the photovoltaic storage system.

[0005] In a first aspect, the present application provides a control method for a power supply system, wherein the power supply system includes an energy storage device, a DC converter, and a converter, wherein the DC converter includes at least two power conversion circuits, one end of the DC converter is connected to the energy storage device, and the other end is connected to a DC bus, one end of the converter is connected to the DC bus, and the other end is used to connect to a power grid, the method comprising:

[0006] When the power supply system is in a black start process and at least two of the power conversion circuits are connected in a first electrical connection manner, in response to the voltage of the DC bus being less than a first voltage threshold, controlling the DC converter to output the electric energy of the energy storage device to the DC bus;

[0007] When the voltage of the DC bus is greater than or equal to the first voltage threshold and the converter is turned on, obtaining voltage information of a terminal of the converter connected to the DC bus;

[0008] Based on the voltage information, the electrical connection between at least two of the power conversion circuits in the DC converter is adjusted so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus.

[0009] According to the control method of the power supply system of the present application, during the black start process, when the voltage of the DC bus reaches a first voltage threshold, the converter turns on and outputs voltage information, obtains the voltage information through a preset communication method, and adjusts the electrical connection method of at least two power conversion circuits based on the voltage information, so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus. When a higher DC output voltage is required, the voltage sharing between multiple power conversion circuits can be achieved by adjusting the electrical connection method, thereby reducing the voltage withstand requirements of the power conversion circuit, and then reducing the cost of the DC converter, so that the cost of the photovoltaic storage system is reduced.

[0010] According to one embodiment of the present application, adjusting the electrical connection mode between at least two power conversion circuits in the DC converter based on the voltage information includes:

[0011] Determining, based on the voltage information, a voltage level of a voltage at one end of the converter connected to the DC bus;

[0012] Based on the voltage level, at least two of the power conversion circuits are adjusted to be connected in a second electrical connection manner, or at least two of the power conversion circuits are maintained to be connected in the first electrical connection manner, and the corresponding DC output voltage is larger when connected in the second electrical connection manner than when connected in the first electrical connection manner.

[0013] According to one embodiment of the present application, the voltage level includes a first voltage level and a second voltage level, the first voltage level is higher than the second voltage level, and the adjusting, based on the voltage level, at least two of the power conversion circuits to be connected in the second electrical connection manner, or maintaining at least two of the power conversion circuits to be connected in the first electrical connection manner, includes:

[0014] When the voltage level is the first voltage level, at least two of the power conversion circuits are adjusted to be connected in the second electrical connection manner.

[0015] According to one embodiment of the present application, the voltage level includes a first voltage level and a second voltage level, the first voltage level is higher than the second voltage level, and the adjusting, based on the voltage level, at least two of the power conversion circuits to be connected in the second electrical connection manner, or maintaining at least two of the power conversion circuits to be connected in the first electrical connection manner, includes:

[0016] When the voltage level is the second voltage level, at least two of the power conversion circuits are kept connected in the first electrical connection manner.

[0017] According to one embodiment of the present application, adjusting the electrical connection mode between at least two power conversion circuits in the DC converter based on the voltage information includes:

[0018] Based on the voltage information, the series connection and / or parallel connection between at least two of the power conversion circuits is adjusted.

[0019] According to one embodiment of the present application, after acquiring voltage information of one end of the converter connected to the DC bus, and before adjusting the electrical connection mode between at least two power conversion circuits in the DC converter, the method further includes:

[0020] Control at least two of the power conversion circuits to stop operating.

[0021] In a second aspect, the present application provides a control device for a power supply system, the power supply system including an energy storage device, a DC converter and a converter, the DC converter including at least two power conversion circuits, one end of the DC converter being connected to the energy storage device and the other end being connected to a DC bus, one end of the converter being connected to the DC bus and the other end being used to connect to a power grid, the device including:

[0022] a first processing module, configured to, when the power supply system is in a black start process and at least two of the power conversion circuits are connected in a first electrical connection manner, control the DC converter to output the electric energy of the energy storage device to the DC bus in response to the voltage of the DC bus being less than a first voltage threshold;

[0023] a second processing module, configured to obtain voltage information of a terminal of the converter connected to the DC bus when the voltage of the DC bus is greater than or equal to the first voltage threshold and the converter is turned on;

[0024] The third processing module is used to adjust the electrical connection mode between at least two of the power conversion circuits in the DC converter based on the voltage information so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus.

[0025] According to the control device of the power supply system of the present application, during the black start process, when the voltage of the DC bus reaches a first voltage threshold, the converter turns on and outputs voltage information, obtains the voltage information through a preset communication method, and adjusts the electrical connection method of at least two power conversion circuits based on the voltage information, so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus. When a higher DC output voltage is required, the voltage sharing between multiple power conversion circuits can be achieved by adjusting the electrical connection method, thereby reducing the voltage withstand requirements of the power conversion circuit, and then reducing the cost of the DC converter, so that the cost of the photovoltaic storage system is reduced.

[0026] In a second aspect, the present application provides a power supply system, comprising:

[0027] Energy storage equipment;

[0028] A DC converter, comprising at least two power conversion circuits, one end of the DC converter being connected to the energy storage device and the other end being connected to a DC bus;

[0029] a converter, one end of which is connected to the DC bus and the other end of which is connected to the power grid;

[0030] The DC converter further includes a first controller, which is configured to execute the power supply system control method according to any one of claims 1 to 6.

[0031] According to the power supply system of the present application, during the black start process, when the voltage of the DC bus reaches a first voltage threshold, the converter turns on and outputs voltage information, obtains the voltage information through a preset communication method, and adjusts the electrical connection method of at least two power conversion circuits based on the voltage information, so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus. When a higher DC output voltage is required, the voltage sharing between multiple power conversion circuits can be achieved by adjusting the electrical connection method, thereby reducing the voltage withstand requirements of the power conversion circuit, and then reducing the cost of the DC converter, so that the cost of the photovoltaic storage system is reduced.

[0032] According to one embodiment of the present application, the DC converter further includes:

[0033] A switching circuit, wherein the switching circuit is connected to the output ends of at least two power conversion circuits, wherein the switching circuit includes a plurality of switching devices, and the first controller is used to control the switching state of each of the switching devices to adjust the electrical connection mode between at least two of the power conversion circuits.

[0034] According to one embodiment of the present application, the converter includes:

[0035] A second controller is communicatively connected to the first controller, and the second controller is used to transmit voltage information of one end of the converter connected to the DC bus to the first controller when the voltage of the DC bus is greater than or equal to the first voltage threshold and the converter is turned on.

[0036] In a fourth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the control method for the power supply system as described in the first aspect above is implemented.

[0037] In a fifth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the control method of the power supply system as described in the first aspect above.

[0038] In a sixth aspect, the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the control method of the power supply system as described in the first aspect above.

[0039] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0041] Figure 1 This is one of the flow charts of the control method of the power supply system provided in the embodiment of the present application;

[0042] Figure 2 This is a second flow chart of the control method of the power supply system provided in an embodiment of the present application;

[0043] Figure 3 This is one of the structural diagrams of the power supply system provided in the embodiment of the present application;

[0044] Figure 4 This is the second structural diagram of the power supply system provided in the embodiment of the present application;

[0045] Figure 5 1 is a schematic structural diagram of a DC converter provided in an embodiment of the present application;

[0046] Figure 6 is a schematic structural diagram of a converter provided in an embodiment of the present application;

[0047] Figure 7is a structural diagram of a control device for a power supply system provided in an embodiment of the present application;

[0048] Figure 8 It is a structural diagram of an electronic device provided in an embodiment of the present application.

[0049] Reference numerals:

[0050] Energy storage device 310, DC converter 320, converter 330, DC bus 340, power grid 200,

[0051] Power conversion circuit 321, first controller 322, first auxiliary power supply 323, switching circuit 324,

[0052] Black-start switch 325 , second controller 331 , second auxiliary power supply 332 , power conversion unit 333 . DETAILED DESCRIPTION

[0053] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0054] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0055] The following, in combination with the accompanying drawings, describes in detail the control method of the power supply system, the control device of the power supply system, the power supply system, the electronic device and the readable storage medium provided in the embodiments of the present application through specific embodiments and their application scenarios.

[0056] The control method of the power supply system provided in the embodiment of the present application can be executed by an electronic device or a functional module or functional entity in the electronic device that can implement the control method of the power supply system. The control method of the power supply system provided in the embodiment of the present application is explained below using the electronic device as an example of the execution subject.

[0057] like Figure 3As shown, the power supply system includes an energy storage device 310, a DC converter 320 and a converter 330. The DC converter 320 includes at least two power conversion circuits 321. One end of the DC converter 320 is connected to the energy storage device 310, and the other end is connected to the DC bus 340. One end of the converter 330 is connected to the DC bus 340, and the other end is used to connect to the power grid 200.

[0058] Among them, the energy storage device 310 is a device that can store the received electrical energy and output the stored electrical energy, the DC converter 320 is a device that can convert a DC voltage of one level into another DC voltage of a different level, the inverter 330 is a device that can convert one form of electrical energy into another form, and the DC bus 340 is a common conductor used to collect and distribute DC power in the power supply system.

[0059] The DC converter 320 includes at least two power conversion circuits 321 . The power conversion circuits 321 can convert a DC voltage at one level into a DC voltage at another different level.

[0060] One end of the power conversion circuit 321 in the DC converter 320 is connected to the energy storage device 310, and the other end is connected to the DC bus 340. The DC power on the DC bus 340 can be converted by the power conversion circuit 321 and transmitted to the energy storage device 310 for storage. The power stored in the energy storage device 310 can also be converted by the power conversion circuit 321 and transmitted to the DC bus 340.

[0061] One end of the converter 330 is connected to the DC bus 340, and the other end is used to connect to the power grid 200. The AC power of the power grid 200 can be converted into DC power by the converter 330 and transmitted to the DC bus 340. The DC power on the DC bus 340 can also be converted into AC power by the converter 330 and transmitted to the power grid 200.

[0062] The DC bus 340 may also be connected to a photovoltaic module, which converts solar energy into DC power and transmits the DC power to the DC bus 340 .

[0063] The control method of the power supply system provided in the embodiment of the present application is used to automatically match and output to the DC bus 340 the voltage required by the DC bus 340 after the black start is completed based on the voltage information of one end of the converter 330 connected to the DC bus 340 when the DC bus 340 loses power and the power supply system is in the black start process.

[0064] like Figure 1 As shown, the control method of the power supply system includes: step 110, step 120 and step 130.

[0065] Step 110: When the power supply system is in a black start process and at least two power conversion circuits 321 are connected in a first electrical connection manner, in response to the voltage of the DC bus 340 being less than a first voltage threshold, control the DC converter 320 to output the electrical energy of the energy storage device 310 to the DC bus 340.

[0066] The first electrical connection mode may be parallel connection.

[0067] In this embodiment, the DC bus 340 of the power supply system is powered off and the power supply system enters a black start process. At the beginning of the black start process, at least two power conversion circuits 321 are controlled to be connected in the first electrical connection mode.

[0068] In this embodiment, the first voltage threshold is a preset voltage value. The fact that the voltage of the DC bus 340 is less than the first voltage threshold indicates that the power grid 200 and the photovoltaic components cannot provide power to the DC bus 340, causing the DC bus 340 to lose power. That is, by detecting that the voltage of the DC bus 340 is less than the first voltage threshold, it is determined that the DC bus 340 is powered off, and the power supply system enters a black start process.

[0069] When the power supply system is in the black start process, the DC converter 320 is controlled to output the electric energy of the energy storage device 310 to the DC bus 340. The electric energy of the energy storage device 310 is converted into electric energy by the DC converter 320 and then output to the DC bus 340 to continuously increase the voltage of the DC bus 340.

[0070] Step 120 : When the voltage of the DC bus 340 is greater than or equal to a first voltage threshold and the converter 330 is turned on, obtain voltage information of a terminal of the converter 330 connected to the DC bus 340 .

[0071] The voltage information may include the voltage value at one end of the converter 330 connected to the DC bus 340 , or the voltage level.

[0072] In this step, the voltage of the DC bus 340 continues to rise. After the voltage of the DC bus 340 rises to the first voltage threshold, the internal components of the converter 330 can obtain electrical energy from the DC bus 340, so that the converter 330 is turned on. After the converter 330 is turned on, it can output voltage information, and the voltage information output by the converter 330 can be obtained through a preset communication method.

[0073] Step 130 : Based on the voltage information, adjust the electrical connection between at least two power conversion circuits 321 in the DC converter 320 so that the DC output voltage of the DC converter 320 matches the voltage at one end of the converter 330 connected to the DC bus 340 .

[0074] It is understandable that the DC output voltage of the DC converter 320 needs to match the voltage of the end of the converter 330 connected to the DC bus 340 so that the power supply system can operate stably.

[0075] After obtaining the voltage information, in order to ensure stable operation of the power supply system, the electrical connection method between at least two power conversion circuits 321 in the DC converter 320 is adjusted according to the voltage at one end of the converter 330 connected to the DC bus 340 to adjust the DC output voltage of the DC converter 320.

[0076] In the related art, when the photovoltaic storage system has no grid input and no light, during the black start process, it is impossible to determine the DC bus voltage level that the DC converter needs to support. Therefore, a high-voltage DC converter is usually used to meet the voltage requirements of the high voltage level. However, the material cost of the components in the high-voltage DC converter is relatively high, which increases the cost of the photovoltaic storage system.

[0077] According to the control method of the power supply system provided in the embodiment of the present application, during the black start process, when the voltage of the DC bus 340 reaches a first voltage threshold, the converter 330 turns on and outputs voltage information, obtains the voltage information through a preset communication method, and adjusts the electrical connection mode of at least two power conversion circuits 321 based on the voltage information, so that the DC output voltage of the DC converter 320 matches the voltage of one end of the converter 330 connected to the DC bus 340. When a higher DC output voltage is required, the voltage sharing between multiple power conversion circuits 321 can be achieved by adjusting the electrical connection mode, thereby reducing the voltage withstand requirement of the power conversion circuit 321, and then reducing the cost of the DC converter 320, so that the cost of the photovoltaic storage system is reduced.

[0078] In some embodiments, adjusting the electrical connection between at least two power conversion circuits 321 in the DC converter 320 based on the voltage information includes:

[0079] Determine the voltage level of the voltage at one end of the converter 330 connected to the DC bus 340 based on the voltage information;

[0080] Based on the voltage level, at least two power conversion circuits 321 are adjusted to be connected in the second electrical connection mode, or at least two power conversion circuits 321 are maintained to be connected in the first electrical connection mode. The corresponding DC output voltage of the second electrical connection mode is larger than that of the first electrical connection mode.

[0081] In this embodiment, the voltage at one end of the converter 330 connected to the DC bus 340 can be divided into multiple voltage levels, each voltage level can correspond to a preset voltage range, and the voltage information can include the size of the voltage value at one end of the converter 330 connected to the DC bus 340. The voltage value at one end of the converter 330 connected to the DC bus 340 is compared with the preset voltage range to determine the corresponding voltage level.

[0082] For example, less than 500V is a voltage level, 500V-650V is a voltage level, 650V-1000V is a voltage level, 1000V-1100V is a voltage level, and greater than 1100V is a voltage level. The voltage value of one end of the converter 330 connected to the DC bus 340 is 700V, then the voltage level of the voltage at one end of the converter 330 connected to the DC bus 340 is determined to be the voltage level corresponding to 650V-1000V.

[0083] In this embodiment, each voltage level can correspond to a different electrical connection method, and the electrical connection method includes a first electrical connection method and a second electrical connection method. At least two power conversion circuits 321 are connected in the second electrical connection method relative to the first electrical connection method, and the corresponding DC output voltage is larger. When the required DC output voltage is larger, two power conversion circuits 321 can be selected to be connected in the second electrical connection method. When the required DC output voltage is smaller, two power conversion circuits 321 can be selected to be connected in the first electrical connection method.

[0084] The required DC output voltage may be determined based on the voltage level, and the at least two power conversion circuits 321 may be adjusted to be connected in the second electrical connection mode, or the at least two power conversion circuits 321 may be kept connected in the first electrical connection mode.

[0085] In some embodiments, the voltage level includes a first voltage level and a second voltage level, the first voltage level being higher than the second voltage level, and based on the voltage level, adjusting the at least two power conversion circuits 321 to be connected in the second electrical connection manner, or maintaining the at least two power conversion circuits 321 to be connected in the first electrical connection manner, includes:

[0086] When the voltage level is the first voltage level, at least two power conversion circuits 321 are adjusted to be connected in the second electrical connection manner.

[0087] In this embodiment, the voltage level is divided into two levels: high voltage and low voltage. The first voltage level is the high voltage level, and the second voltage level is the low voltage level.

[0088] When the voltage level is the first voltage level, it is determined that the required DC output voltage is larger, and at least two power conversion circuits 321 are adjusted to be connected in a second electrical connection manner. Multiple power conversion circuits 321 share the provision of the DC output voltage so that the DC output voltage matches the first voltage level.

[0089] In some embodiments, the voltage level includes a first voltage level and a second voltage level, the first voltage level being higher than the second voltage level, and based on the voltage level, adjusting the at least two power conversion circuits 321 to be connected in the second electrical connection manner, or maintaining the at least two power conversion circuits 321 to be connected in the first electrical connection manner, includes:

[0090] When the voltage level is the second voltage level, the at least two power conversion circuits 321 are kept connected in the first electrical connection manner.

[0091] When the voltage level is the second voltage level, it is determined that the required DC output voltage is smaller, and at least two power conversion circuits 321 are kept connected in the first electrical connection mode so that the DC output voltage matches the second voltage level.

[0092] In some embodiments, adjusting the electrical connection between at least two power conversion circuits 321 in the DC converter 320 based on the voltage information includes:

[0093] Based on the voltage information, the series connection and / or parallel connection between the at least two power conversion circuits 321 is adjusted.

[0094] In this embodiment, when the DC converter 320 includes two power conversion circuits 321 , the two power conversion circuits 321 can be adjusted to be connected in series or in parallel based on the voltage information.

[0095] When the DC converter 320 includes more than two power conversion circuits 321, the multiple power conversion circuits 321 can be adjusted to be connected in series or in parallel based on voltage information, or the multiple power conversion circuits 321 can be adjusted to be connected in series and in parallel at the same time.

[0096] A specific embodiment of a control method for a power supply system is introduced below.

[0097] In this embodiment, the first electrical connection mode may be parallel connection, and the second electrical connection mode may be series connection.

[0098] The DC bus 340 of the power supply system loses power and the power supply system enters a black start process. At the beginning of the black start process, at least two power conversion circuits 321 are controlled to be connected in parallel. Each power conversion circuit 321 can work independently. If one of them fails, the other circuits can continue to operate, thereby ensuring the reliability of the system.

[0099] The DC converter 320 is controlled to output the electric energy of the energy storage device 310 to the DC bus 340. When the voltage of the DC bus 340 is greater than or equal to the first voltage threshold and the converter 330 is turned on, the voltage information of the end of the converter 330 connected to the DC bus 340 is obtained.

[0100] When the voltage level is determined to be the first voltage level based on the voltage information, at least two power conversion circuits 321 are adjusted to be connected in series, and the voltages of multiple power conversion circuits 321 are superimposed to meet the high voltage output requirements. It is possible to use a power conversion circuit 321 with a lower voltage level to achieve high voltage output.

[0101] When the voltage level is determined to be the second voltage level based on the voltage information, at least two power conversion circuits 321 are kept connected in parallel.

[0102] In some embodiments, after obtaining voltage information at one end of the converter 330 connected to the DC bus 340 and before adjusting the electrical connection between the at least two power conversion circuits 321 in the DC converter 320, the method further includes:

[0103] Control at least two power conversion circuits 321 to stop working.

[0104] In this embodiment, before adjusting the electrical connection mode between at least two power conversion circuits 321 in the DC converter 320, controlling at least two power conversion circuits 321 to stop working can reduce the current shock or voltage transient of the power conversion circuit 321 and improve the operating safety of the DC converter 320.

[0105] The control method of the power supply system provided in the embodiment of the present application can be executed by a control device of the power supply system. In the embodiment of the present application, the control device of the power supply system provided in the embodiment of the present application is described by taking the control device of the power supply system executing the control method of the power supply system as an example.

[0106] An embodiment of the present application also provides a control device for a power supply system.

[0107] like Figure 7 As shown, the control device of the power supply system includes:

[0108] The first processing module 710 is configured to, when the power supply system is in a black start process and the at least two power conversion circuits 321 are connected in a first electrical connection manner, control the DC converter 320 to output the electric energy of the energy storage device 310 to the DC bus 340 in response to the voltage of the DC bus 340 being less than a first voltage threshold;

[0109] The second processing module 720 is configured to obtain voltage information of a terminal of the converter 330 connected to the DC bus 340 when the voltage of the DC bus 340 is greater than or equal to the first voltage threshold and the converter 330 is turned on;

[0110] The third processing module 730 is used to adjust the electrical connection between at least two power conversion circuits 321 in the DC converter 320 based on the voltage information so that the DC output voltage of the DC converter 320 matches the voltage at one end of the converter 330 connected to the DC bus 340.

[0111] According to the control device of the power supply system provided in the embodiment of the present application, during the black start process, when the voltage of the DC bus 340 reaches a first voltage threshold, the converter 330 turns on and outputs voltage information, obtains the voltage information through a preset communication method, and adjusts the electrical connection mode of at least two power conversion circuits 321 based on the voltage information, so that the DC output voltage of the DC converter 320 matches the voltage of one end of the converter 330 connected to the DC bus 340. When a higher DC output voltage is required, the voltage sharing between multiple power conversion circuits 321 can be achieved by adjusting the electrical connection mode, thereby reducing the voltage withstand requirement of the power conversion circuit 321, and further reducing the cost of the DC converter 320, so that the cost of the photovoltaic storage system is reduced.

[0112] In some embodiments, the third processing module 730 is configured to determine a voltage level of a voltage at a terminal of the converter 330 connected to the DC bus 340 based on the voltage information;

[0113] Based on the voltage level, at least two power conversion circuits 321 are adjusted to be connected in the second electrical connection mode, or at least two power conversion circuits 321 are maintained to be connected in the first electrical connection mode. The corresponding DC output voltage of the second electrical connection mode is larger than that of the first electrical connection mode.

[0114] In some embodiments, the voltage level includes a first voltage level and a second voltage level, the first voltage level is higher than the second voltage level, and the third processing module 730 is used to adjust at least two power conversion circuits 321 to be connected in a second electrical connection manner when the voltage level is the first voltage level.

[0115] In some embodiments, the voltage level includes a first voltage level and a second voltage level, the first voltage level is higher than the second voltage level, and the third processing module 730 is used to keep at least two power conversion circuits 321 connected in a first electrical connection manner when the voltage level is the second voltage level.

[0116] In some embodiments, the third processing module 730 is configured to adjust the series connection and / or parallel connection between at least two power conversion circuits 321 based on the voltage information.

[0117] In some embodiments, the third processing module 730 is further configured to control at least two power conversion circuits 321 to stop operating.

[0118] The control device of the power supply system in the embodiment of the present application can be an electronic device, or a component in the electronic device, such as an integrated circuit or a chip.

[0119] The control device of the power supply system in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an iOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0120] The control device of the power supply system provided in the embodiment of the present application can achieve Figure 1 and Figure 2 To avoid repetition, the various processes implemented in the method embodiment are not described here.

[0121] An embodiment of the present application also provides a power supply system.

[0122] like Figure 3 As shown, the power supply system includes an energy storage device 310 , a DC converter 320 and a converter 330 .

[0123] Among them, the DC converter 320 includes at least two power conversion circuits 321, one end of the DC converter 320 is connected to the energy storage device 310, and the other end is connected to the DC bus 340, one end of the converter 330 is connected to the DC bus 340, and the other end is used to connect to the power grid 200.

[0124] The DC converter 320 further includes a first controller 322 , which is configured to execute the above-mentioned control method for the power supply system.

[0125] like Figure 4 As shown, the DC converter 320 includes two power conversion circuits 321 , a black start switch 325 , a first auxiliary power supply 323 and a first controller 322 .

[0126] The first auxiliary power supply 323 can obtain power from the DC bus 340 or from the energy storage device 310 through the black start switch 325 to provide auxiliary power for various components inside the DC converter 320 .

[0127] When the DC bus 340 loses power and the black start switch 325 is closed, the first auxiliary power supply 323 draws power from the energy storage device 310 to provide auxiliary power for the various components inside the DC converter 320. After receiving power, the first controller 322 controls the two power conversion circuits 321 in parallel by default, and controls the start-up of the two power conversion circuits 321 to enter the working state. After the two power conversion circuits 321 obtain power from the energy storage device 310, they raise the voltage of the DC bus 340.

[0128] According to the power supply system provided by the embodiment of the present application, during the black start process, when the voltage of the DC bus 340 reaches a first voltage threshold, the converter 330 turns on and outputs voltage information, obtains the voltage information through a preset communication method, and adjusts the electrical connection method of at least two power conversion circuits 321 based on the voltage information, so that the DC output voltage of the DC converter 320 matches the voltage of one end of the converter 330 connected to the DC bus 340. When a higher DC output voltage is required, the voltage sharing between multiple power conversion circuits 321 can be achieved by adjusting the electrical connection method, thereby reducing the voltage withstand requirements of the power conversion circuit 321, and then reducing the cost of the DC converter 320, so that the cost of the photovoltaic storage system is reduced.

[0129] In some embodiments, as Figure 4 As shown, the DC converter 320 further includes a switching circuit 324 .

[0130] The switching circuit 324 is connected to the output ends of at least two power conversion circuits 321. The switching circuit 324 includes multiple switching devices. The first controller 322 is used to control the switching state of each switching device to adjust the electrical connection mode between the at least two power conversion circuits 321.

[0131] like Figure 5 As shown, the switching circuit 324 includes a switch device K1, a switch device K2 and a switch device K3. When the first controller 322 controls the switch device K1 and the switch device K3 to be attracted and controls the switch device K2 to be disconnected, the two power conversion circuits 321 are connected in parallel. When the first controller 322 controls the switch device K2 to be attracted and controls the switch device K1 and the switch device K3 to be disconnected, the two power conversion circuits 321 are connected in series.

[0132] In some embodiments, the converter 330 includes a second controller 331 .

[0133] The second controller 331 is communicatively connected to the first controller 322. The second controller 331 is used to transmit voltage information of one end of the converter 330 connected to the DC bus 340 to the first controller 322 when the voltage of the DC bus 340 is greater than or equal to the first voltage threshold and the converter 330 is turned on.

[0134] like Figure 6 As shown, the converter 330 includes a power conversion unit 333, a second auxiliary power supply 332 and a second controller 331. When the voltage of the DC bus 340 is greater than or equal to the first voltage threshold, the second auxiliary power supply 332 obtains electric energy from the DC bus 340 to provide auxiliary power for the internal components of the converter 330. After receiving power, the second controller 331 establishes communication with the first controller 322 and transmits voltage information to the first controller 322.

[0135] The control method of the power supply system provided in the embodiment of the present application can automatically match the voltage of the DC bus 340 required after the black start according to the voltage level of the converter 330 during the black start process after the power supply system is completely powered off, thereby determining the DC output voltage, improving the adaptability of the system in different scenarios, and at the same time ensuring safety and reliability.

[0136] The following describes a specific embodiment of a control method for a power supply system when the power supply system is configured with a converter 330 of a low voltage level.

[0137] The DC converter 320 includes two power conversion circuits 321. After the black start switch 325 is closed, the first auxiliary power supply 323 draws power from the energy storage device 310 to provide auxiliary power for the internal components of the DC converter 320. After the first controller 322 is powered, it controls the switching circuit 324 to output in parallel by default, that is, the two power conversion circuits 321 are connected in parallel, and controls the startup of the two power conversion circuits 321 to enter the working state. After the two power conversion circuits 321 obtain power from the energy storage device 310, they lift the DC bus 340 through the switching circuit 324. When the voltage of the DC bus 340 reaches the first voltage threshold, the second auxiliary power supply 332 obtains power from the DC bus 340 to provide auxiliary power for the internal components of the converter 330. After the second controller 331 is powered on, it establishes communication with the first controller 322 and informs the converter 330 that the current voltage level is the low voltage level, that is, the second voltage level. Since the first controller 322 controls the switching circuit 324 to output in parallel by default after power-on, it continues to maintain the current working state and continue to operate after receiving the information that the converter 330 is at the low voltage level.

[0138] The following describes a specific embodiment of a control method for a power supply system when the power supply system is configured with a high-voltage converter 330 .

[0139] The DC converter 320 includes two power conversion circuits 321. After the black start switch 325 is closed, the first auxiliary power supply 323 draws power from the energy storage device 310 to provide auxiliary power for the internal components of the DC converter 320. After the first controller 322 is powered, it controls the switching circuit 324 to output in parallel by default, that is, the two power conversion circuits 321 are connected in parallel, and controls the start-up of the two power conversion circuits 321 to enter the working state. After the two power conversion circuits 321 obtain power from the energy storage device 310, they raise the voltage of the DC bus 340 through the switching circuit 324. When the voltage of the DC bus 340 reaches the first voltage threshold, the second auxiliary power supply 332 obtains power from the DC bus 340 to provide the converter. The internal devices of 330 provide auxiliary power. After the second controller 331 is powered on, it establishes communication with the first controller 322 and informs it that the current voltage level of the converter 330 is the high voltage level, that is, the first voltage level. Since the first controller 322 controls the switching circuit 324 to output in parallel by default after powering on, after receiving the information that the converter 330 is at the high voltage level, the first controller 322 first stops the two power conversion circuits 321 from working, and then switches the output of the switching circuit 324 to the series output, and then starts the two power conversion circuits 321 again. The two power conversion circuits 321 draw power from the energy storage device 310 and output through the switching circuit 324 to maintain the DC bus 340 at a high voltage level.

[0140] Another specific embodiment of a control method for a power supply system is described below.

[0141] The DC converter 320 includes two power conversion circuits 321 .

[0142] like Figure 2 As shown, step 1 is to determine whether the black start switch 325 is closed.

[0143] Step 2: The first auxiliary power supply 323 draws power from the energy storage device 310 to provide auxiliary power for various components inside the DC converter 320 .

[0144] Step 3: After the first controller 322 is powered on, it controls the switching circuit 324 to output in parallel by default.

[0145] Step 4: The first controller 322 controls the two power conversion circuits 321 to obtain power from the energy storage device 310 and then raise the voltage of the DC bus 340 through the switching circuit 324 .

[0146] Step 4: Determine whether the voltage of the DC bus 340 is greater than or equal to the first voltage threshold.

[0147] Step 5: The second auxiliary power supply 332 obtains power from the DC bus 340 to provide auxiliary power for internal components of the converter 330 .

[0148] Step 6: After receiving power, the second controller 331 establishes communication with the first controller 322 and informs the first controller 322 of the current voltage level of the converter 330 .

[0149] Step 7: When the voltage level is low, continue to operate in the current working state.

[0150] Step 8: When the voltage level is the high voltage level, the first controller 322 stops the two power conversion circuits 321 from operating.

[0151] Step 9: Switch the output of the switching circuit 324 to a series output.

[0152] Step 10: Start the two power conversion circuits 321 again.

[0153] In some embodiments, as Figure 8 As shown, an embodiment of the present application also provides an electronic device 800, including a processor 801, a memory 802, and a computer program stored in the memory 802 and executable on the processor 801. When the program is executed by the processor 801, each process of the control method embodiment of the above-mentioned power supply system is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0154] An embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the above-mentioned power supply system control method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0155] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0156] An embodiment of the present application further provides a computer program product, including a computer program, which implements the control method of the power supply system when executed by a processor.

[0157] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0158] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned power supply system control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0159] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0160] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0161] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, or of course by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal to execute the methods described in each embodiment of the present application.

[0162] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

[0163] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0164] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A control method for a power supply system, characterized in that: The power supply system includes an energy storage device, a DC converter and a converter, wherein the DC converter includes at least two power conversion circuits, one end of the DC converter is connected to the energy storage device, and the other end is connected to the DC bus, one end of the converter is connected to the DC bus, and the other end is used to connect to the power grid, and the method includes: When the power supply system is in a black start process and at least two of the power conversion circuits are connected in a first electrical connection manner, in response to the voltage of the DC bus being less than a first voltage threshold, controlling the DC converter to output the electric energy of the energy storage device to the DC bus; When the voltage of the DC bus is greater than or equal to the first voltage threshold and the converter is turned on, obtaining voltage information of a terminal of the converter connected to the DC bus; Based on the voltage information, the electrical connection between at least two of the power conversion circuits in the DC converter is adjusted so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus.

2. The control method of the power supply system according to claim 1, characterized in that: The adjusting the electrical connection mode between at least two power conversion circuits in the DC converter based on the voltage information includes: Determining, based on the voltage information, a voltage level of a voltage at one end of the converter connected to the DC bus; Based on the voltage level, at least two of the power conversion circuits are adjusted to be connected in a second electrical connection manner, or at least two of the power conversion circuits are maintained to be connected in the first electrical connection manner, and the corresponding DC output voltage is larger when connected in the second electrical connection manner than when connected in the first electrical connection manner.

3. The control method of the power supply system according to claim 2, characterized in that: The voltage level includes a first voltage level and a second voltage level, the first voltage level being higher than the second voltage level, and adjusting the at least two power conversion circuits to be connected in the second electrical connection manner, or maintaining the at least two power conversion circuits to be connected in the first electrical connection manner based on the voltage levels, includes: When the voltage level is the first voltage level, at least two of the power conversion circuits are adjusted to be connected in the second electrical connection manner.

4. The control method of the power supply system according to claim 2, characterized in that: The voltage level includes a first voltage level and a second voltage level, the first voltage level being higher than the second voltage level, and adjusting the at least two power conversion circuits to be connected in the second electrical connection manner, or maintaining the at least two power conversion circuits to be connected in the first electrical connection manner based on the voltage levels, includes: When the voltage level is the second voltage level, at least two of the power conversion circuits are kept connected in the first electrical connection manner.

5. The control method for a power supply system according to any one of claims 1 to 4, characterized in that: The adjusting the electrical connection mode between at least two power conversion circuits in the DC converter based on the voltage information includes: Based on the voltage information, the series connection and / or parallel connection between at least two of the power conversion circuits is adjusted.

6. The power supply system control method according to any one of claims 1 to 4, characterized in that: After acquiring voltage information of one end of the converter connected to the DC bus, and before adjusting the electrical connection between at least two power conversion circuits in the DC converter, the method further includes: Control at least two of the power conversion circuits to stop operating.

7. A control device for a power supply system, characterized in that: The power supply system includes an energy storage device, a DC converter and a converter. The DC converter includes at least two power conversion circuits. One end of the DC converter is connected to the energy storage device and the other end is connected to the DC bus. One end of the converter is connected to the DC bus and the other end is used to connect to the power grid. The device includes: a first processing module, configured to, when the power supply system is in a black start process and at least two of the power conversion circuits are connected in a first electrical connection manner, control the DC converter to output the electric energy of the energy storage device to the DC bus in response to the voltage of the DC bus being less than a first voltage threshold; a second processing module, configured to obtain voltage information of a terminal of the converter connected to the DC bus when the voltage of the DC bus is greater than or equal to the first voltage threshold and the converter is turned on; The third processing module is used to adjust the electrical connection mode between at least two of the power conversion circuits in the DC converter based on the voltage information so that the DC output voltage of the DC converter matches the voltage of one end of the converter connected to the DC bus.

8. A power supply system, characterized in that: include: Energy storage equipment; A DC converter, comprising at least two power conversion circuits, one end of the DC converter being connected to the energy storage device and the other end being connected to a DC bus; a converter, one end of which is connected to the DC bus and the other end of which is connected to the power grid; The DC converter further includes a first controller, which is configured to execute the power supply system control method according to any one of claims 1 to 6.

9. The power supply system according to claim 8, characterized in that: The DC converter further includes: A switching circuit, wherein the switching circuit is connected to the output ends of at least two power conversion circuits, wherein the switching circuit includes a plurality of switching devices, and the first controller is used to control the switching state of each of the switching devices to adjust the electrical connection mode between at least two of the power conversion circuits.

10. The power supply system according to claim 8 or 9, characterized in that: The converter comprises: A second controller is communicatively connected to the first controller, and the second controller is used to transmit voltage information of one end of the converter connected to the DC bus to the first controller when the voltage of the DC bus is greater than or equal to the first voltage threshold and the converter is turned on.

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