Charging system and charging station

Abstract

The embodiment of the utility model provides a charging system and a charging station, the charging system comprises an AC-DC module, a first DC-DC module, a second DC-DC module, a DC bus and k energy storage modules, the AC-DC module comprises n AC-DC converters, and the first DC-DC module comprises m DC-DC converters; the input ends of the n AC-DC converters are connected with an AC power grid, the output ends of the n AC-DC converters are respectively connected with one section of the DC bus, each section of the DC bus is connected with the output end of at least one AC-DC converter, and the first ends of the m DC-DC converters are respectively connected with one section of the DC bus; each section of direct current bus is connected with the first end of at least one DC-DC converter in the m DC-DC converters; the second ends of the m DC-DC converters are used for being connected with at least one electric automobile. The efficiency of the charging system can be improved.

Description

Technical Field

[0001] This application relates to the technical field of electronic circuits, and particularly to a charging system and a charging station. Background Art

[0002] At present, in the topology of the charging system in the industry, the three-phase alternating current of the power grid is converted into high-voltage direct current to the DC bus through a transformer and an alternating current-direct current (AC-DC) module, and an electric vehicle is connected to the DC bus through a direct current-direct current (DC-DC) module. Compared with a single high-power device, multiple low-power devices in parallel have advantages in terms of economy, maintainability, reliability, etc., so the AC-DC module and the DC-DC module often adopt a scheme of multiple units in parallel. However, the battery voltages of different electric vehicles are usually different. When multiple electric vehicles are charging simultaneously, the voltages at the vehicle ends of the DC-DC modules connected to the electric vehicles are different, while the voltages at the DC bus ends are the same, which will cause multiple DC-DC modules to operate in different states, and not all DC-DC modules can operate at the best efficiency state, resulting in high losses and low efficiency of the entire charging system. Summary of the Utility Model

[0003] Embodiments of this application provide a charging system and a charging station, which can improve the efficiency of the charging system.

[0004] In a first aspect of an embodiment of the present application, a charging system is provided, including an AC-DC module, a first DC-DC module, a second DC-DC module, a DC bus, and k energy storage modules. The AC-DC module includes n AC-DC converters, and the first DC-DC module includes m DC-DC converters; the DC bus includes multiple segments that can be connected in a switchable manner in sequence; the input ends of the n AC-DC converters are connected to an AC power grid, the output ends of the n AC-DC converters are respectively connected to a segment of the DC bus, and each segment of the DC bus is connected to the output ends of at least one AC-DC converter. The first ends of the m DC-DC converters are respectively connected to a segment of the DC bus, and each segment of the DC bus is connected to the first ends of at least one of the m DC-DC converters. The second ends of the m DC-DC converters are used to connect at least one electric vehicle; each energy storage module is connected to a segment of the DC bus through the second DC-DC module and / or each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module; m, n, and p are all integers greater than or equal to 2, k is an integer greater than or equal to 1, p is less than or equal to n, p is less than or equal to m, and k is less than or equal to p.

[0005] Optionally, the sum of the powers of at least one DC-DC converter connected to each electric vehicle is greater than or equal to the power requirement of each electric vehicle.

[0006] Optionally, any two adjacent segments of the DC bus are connected by a first switch.

[0007] Optionally, when any of the first switches is disconnected, the voltages of the two segments of the DC bus connected to the disconnected first switch are adjustable.

[0008] Optionally, when any of the first switches is disconnected, the voltages of the two segments of the DC bus connected to the disconnected first switch are different.

[0009] Optionally, when any of the first switches is closed, the voltages of the two segments of the DC bus connected to the closed first switch are the same.

[0010] Optionally, the DC bus is divided into p segments by p - 1 first switches, and the charging system further includes a controller. The first segment of the DC bus is connected to the first end of the first DC-DC converter, the second end of the first DC-DC converter is connected to the first electric vehicle, and when the voltage of the first segment of the DC bus is adjustable, the controller is configured to control the states of the p - 1 first switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle; wherein, the first electric vehicle is one of the at least one electric vehicle, the first DC-DC converter is any one of the m DC-DC converters, and the first segment of the DC bus is the segment of the DC bus connected to the first DC-DC converter.

[0011] Optionally, the DC bus is divided into p segments by p - 1 first switches, and the controller is configured to adjust the voltage of the first segment of the DC bus according to the required voltage of the first electric vehicle.

[0012] Optionally, the controller is configured to adjust the voltage of the first segment of the DC bus according to the required voltage of the first electric vehicle, including:

[0013] The controller controls the states of the p - 1 first switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle;

[0014] When the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, the controller adjusts the voltage of the first segment of the DC bus according to the required voltage of the first electric vehicle so that the first DC-DC converter operates in the optimal efficiency state.

[0015] Optionally, the second DC-DC module includes k second DC-DC converters, and each energy storage module is connected to a segment of the DC bus through the second DC-DC module and / or each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module, including:

[0016] Each energy storage module is connected to a segment of the DC bus through one of the k second DC-DC converters and one of the k second switches; or,

[0017] Each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module; or,

[0018] Each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module; or,

[0019] Each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module and one of the q third switches, where q is a positive integer less than or equal to k.

[0020] Optionally, the controller is further configured to control the states of the p - 1 first switches and the states of the k second switches, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0021] Optionally, when each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module, the controller is further configured to control the states of the p - 1 first switches and the states of the q third switches, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0022] Optionally, when each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and the first energy storage module needs to be charged, the controller is configured to control the second switch corresponding to the first energy storage module to be in the on state, so that the AC grid charges the first energy storage module, and the first energy storage module is any one of the k energy storage modules.

[0023] Optionally, the charging system further includes a switch unit, and the second ends of the m DC-DC converters are connected to at least one electric vehicle through the switch unit.

[0024] Optionally, the charging system further includes a photovoltaic module, and the photovoltaic module is connected to at least one section of the DC bus through a third DC-DC module.

[0025] A second aspect of the embodiments of the present application provides a charging station, including the charging system according to the first aspect of the embodiments of the present application.

[0026] The charging system according to the embodiment of the present application includes an AC-DC module, a first DC-DC module, a second DC-DC module, a DC bus, and k energy storage modules. The AC-DC module includes n AC-DC converters, and the first DC-DC module includes m DC-DC converters; the DC bus includes multiple segments that can be connected in a turn-on and turn-off manner; the input ends of the n AC-DC converters are connected to the AC power grid, and the output ends of the n AC-DC converters are respectively connected to one segment of the DC bus, and each segment of the DC bus is connected to the output ends of at least one AC-DC converter. The first ends of the m DC-DC converters are respectively connected to one segment of the DC bus, and each segment of the DC bus is connected to the first ends of at least one of the m DC-DC converters. The second ends of the m DC-DC converters are used to connect at least one electric vehicle; each energy storage module is correspondingly connected to one segment of the DC bus through the second DC-DC module and / or each energy storage module is correspondingly connected to the second end of one of the m DC-DC converters through the second DC-DC module; m, n, and p are all integers greater than or equal to 2, k is an integer greater than or equal to 1, p is less than or equal to n, p is less than or equal to m, and k is less than or equal to p. The DC bus includes multiple segments that can be connected in a turn-on and turn-off manner, and the voltage of each segment of the DC bus can be flexibly adjusted, which can improve the working efficiency of the DC-DC converter, thereby improving the efficiency of the charging system. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 is a schematic structural diagram of a charging system provided by an embodiment of the present application;

[0029] Figure 2 is a schematic structural diagram of another charging system provided by an embodiment of the present application;

[0030] Figure 3 is a schematic structural diagram of another charging system provided by an embodiment of the present application;

[0031] Figure 4 is a schematic structural diagram of another charging system provided by an embodiment of the present application;

[0032] Figure 5 is a schematic structural diagram of another charging system provided by an embodiment of the present application;

[0033] Figure 6 is a schematic structural diagram of another charging system provided by an embodiment of the present application;

[0034] Figure 7 is a schematic structural diagram of another charging system provided by an embodiment of the present application;

[0035] Figure 8 is a schematic structural diagram of a charging station provided by an embodiment of the present application. Specific Embodiments

[0036] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0037] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned accompanying drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, products or devices.

[0038] Referring to "embodiment" in the present application means that a specific feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application may be combined with other embodiments.

[0039] Please refer to Figure 1 , Figure 1 is a schematic structural diagram of a charging system provided by an embodiment of the present application. As Figure 1 shown, the charging system includes an AC-DC module, a first DC-DC module, a second DC-DC module, a DC bus, and k energy storage modules (such as Figure 1 shown energy storage module 1, energy storage module 2, energy storage module 3,..., energy storage module k), the AC-DC module includes n AC-DC converters (such as Figure 1 shown AC-DC1, AC-DC2, AC-DC3,..., AC-DCn), the first DC-DC module includes m DC-DC converters (such asFigure 1 The DC-DC1, DC-DC2, DC-DC3, …, DC-DCm) as shown; the DC bus includes multiple segments (such as Figure 1 the DC bus segments 1, DC bus segment 2, DC bus segment 3, …, DC bus segment p shown as the thick black line segments, which are p segments that the DC bus can be connected to in a connectable and disconnectable manner); the input ends of the n AC-DC converters are connected to the AC power grid, and the output ends of the n AC-DC converters are respectively connected to one segment of the DC bus (such as Figure 1 as shown, one segment of the DC bus can be one of the DC bus segments 1, DC bus segment 2, DC bus segment 3, …, DC bus segment p shown as the thick black line segments), each segment of the DC bus is connected to the output end of at least one AC-DC converter, the first ends of the m DC-DC converters are respectively connected to one segment of the DC bus, each segment of the DC bus is connected to the first end of at least one of the m DC-DC converters, and the second ends of the m DC-DC converters are used to connect at least one electric vehicle; each energy storage module is connected to one segment of the DC bus through the second DC-DC module (the second DC-DC module may include Figure 1 the DC-DC_1, DC-DC_2, DC-DC_3, …, DC-DC_k as shown) and / or each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module; m, n, p are all integers greater than or equal to 2, k is an integer greater than or equal to 1, p is less than or equal to n, p is less than or equal to m, and k is less than or equal to p. Figure 1 Taking m = n = k = p as an example.

[0040] In the embodiment of the present application, the alternating current-direct current (AC-DC) module can convert alternating current into direct current. For example, if the alternating current on the AC power grid is 10 kilovolts (kV), the AC-DC module can convert 10 kV alternating current into 800V direct current and output 800V direct current to the DC bus. The DC output voltage of each of the n AC-DC converters in the AC-DC module can be changed according to requirements, and the DC output voltages of the n AC-DC converters can be the same or different.

[0041] A direct current-direct current (DC-DC) module can convert one DC voltage into another DC voltage. For example, if the required voltage of an electric vehicle connected to the second terminal of a certain DC-DC converter among m DC-DC converters is 400V, then this DC-DC converter can convert the DC bus voltage connected thereto into 400V and output it to the electric vehicle.

[0042] An electric vehicle is a vehicle that can be driven by electric energy. An electric vehicle may include a power battery. The power battery may include at least two single cells connected in series.

[0043] An energy storage module can be a device for storing energy. The energy storage module may include an energy storage battery or a supercapacitor. The energy storage battery is not the same type of battery as the power battery in the electric vehicle. The energy storage battery has a lower energy density and a longer lifespan and belongs to an energy-type battery. The power battery has a higher energy density and a longer endurance and belongs to a power-type battery. Exemplarily, the energy storage module may include at least two energy storage batteries connected in series. The energy storage module can also be referred to as an energy storage battery cluster.

[0044] In the embodiments of the present application, when the energy storage module needs to be charged, the DC-DC converter connected to the energy storage module can be controlled to charge the energy storage module. When the energy storage module needs to discharge, the DC-DC converter connected to the energy storage module can be controlled to discharge to the DC bus. Exemplarily, when the energy storage module 1 needs to be charged, DC-DC_1 can be controlled to convert the direct current on the DC bus segment 1 into the charging voltage of the energy storage module 1, so as to charge the energy storage module 1. When the energy storage module 1 needs to discharge, DC-DC_1 can be controlled to convert the voltage output by the energy storage module 1 into the voltage of the DC bus segment 1, so as to realize the discharge of the energy storage module 1 to the DC bus segment 1. It should be noted that Figure 1 The DC-DC_1, DC-DC_2, DC-DC_3, …, DC-DC_k shown are all bidirectional DC-DC converters. A bidirectional DC-DC converter is a DC-DC converter that supports bidirectional output.

[0045] The input ends of n AC-DC converters are connected to the AC power grid. The input ends of the n AC-DC converters can be directly connected to the AC power grid or can be connected to the AC power grid through a transformer (as Figure 1 shown).

[0046] The second ends of m DC-DC converters are used to connect at least one electric vehicle. Among the second ends of the m DC-DC converters, some DC-DC converters can be connected to the electric vehicle, and some DC-DC converters may not be connected to the electric vehicle (for example, when there is no electric vehicle charging in this charging system). As Figure 1As shown, among the m DC-DC converters, each DC-DC converter is connected to an electric vehicle (such as Figure 1 the electric vehicle 1, electric vehicle 2, electric vehicle 3, …, electric vehicle m shown) as an example.

[0047] The second end of the DC-DC converter can be a charging gun. When the charging gun is inserted into the electric vehicle, the second end of the DC-DC converter is connected to the electric vehicle.

[0048] Among them, the DC bus includes multiple segments that can be connected in a switchable manner in sequence. Such as Figure 1 shown, the DC bus segment 1 and the DC bus segment 2 are connected through the first switch Ka1, the DC bus segment 2 and the DC bus segment 3 are connected through the first switch Ka2, and the DC bus segment 1 and the DC bus segment 3 are connected through the first switch Ka1 and the first switch Ka2.

[0049] Optionally, as Figure 1 shown, the charging system further includes a photovoltaic module, and the photovoltaic module is connected to at least one segment of the DC bus through a third DC-DC module.

[0050] The third DC-DC module can include at least one DC-DC converter. The photovoltaic module can include at least one output port, and each output port can output energy to the DC bus through a DC-DC converter in the third DC-DC module.

[0051] Among them, the photovoltaic module is a component that can generate electricity through solar energy. The voltage of the photovoltaic module is not the voltage of the DC bus. For example, the photovoltaic module is composed of 50 or 100 photovoltaic panels connected in series, and the output voltage is between 200V and 300V. The voltage of the DC bus is 600 - 800V. The photovoltaic module discharges to the DC bus through the third DC-DC module. Among them, the energy storage module and the electric vehicle can both charge through the DC bus and discharge to the DC bus. Exemplarily, if the electric vehicle requires a charging power of 500 kilowatts and the power generation power of the photovoltaic module is 100 kilowatts, then the remaining 400 kilowatts are provided from the AC grid or the energy storage module.

[0052] After the energy of the photovoltaic module reaches the DC bus, it can supply power to the energy storage module and the electric vehicle. It can be specifically allocated according to requirements.

[0053] Optionally, any two adjacent segments in the DC bus are connected through a first switch.

[0054] Such as Figure 1As shown, DC bus segment 1 and DC bus segment 2 are two adjacent segments in the DC bus, DC bus segment 2 and DC bus segment 3 are two adjacent segments in the DC bus, and DC bus segment p - 1 and DC bus segment p are two adjacent segments in the DC bus. There is a first switch Ka1 connecting DC bus segment 1 and DC bus segment 2, a first switch Ka2 connecting DC bus segment 2 and DC bus segment 3, and a first switch Kap - 1 connecting DC bus segment p - 1 and DC bus segment p.( Figure 1 not shown in

[0055] Optionally, when any of the first switches is open, the voltages of the two segments of the DC bus connected by the open first switch are adjustable. Exemplarily, when the first switch Ka1 is in the conducting state, the voltages of DC bus segment 1 and DC bus segment 2 are equal; when the first switch Ka1 is in the open state, the voltages of DC bus segment 1 and DC bus segment 2 can be adjusted separately.

[0056] Optionally, when any of the first switches is open, the voltages of the two segments of the DC bus connected by the open first switch are different. Exemplarily, when the first switch Ka1 is in the open state, the voltages of DC bus segment 1 and DC bus segment 2 can be adjusted separately so that the voltages of DC bus segment 1 and DC bus segment 2 are different.

[0057] Optionally, when any of the first switches is closed, the voltages of the two segments of the DC bus connected by the closed first switch are the same. Exemplarily, when the first switch Ka1 is in the conducting state, the voltages of DC bus segment 1 and DC bus segment 2 are equal.

[0058] Optionally, the DC bus is divided into p segments by p - 1 first switches, and any two adjacent DC bus segments are connected by a first switch. Only p - 1 first switches are needed to achieve the connection between P DC bus segments. Using a smaller number of first switches to achieve the connection between P DC bus segments can reduce costs. Whether the P DC bus segments need to be connected is related to the power demand of the electric vehicle connected to the second ends of m DC - DC converters.

[0059] In the embodiments of the present application, any two of the p DC bus segments can be connected by p - 1 first switches, and the voltages of the p DC bus segments can be adjusted flexibly, which can improve the working efficiency of the DC - DC converter and thus improve the efficiency of the charging system.

[0060] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of another charging system provided by the embodiments of the present application. Figure 2 It is obtained on the basis of Figure 1 as shown inFigure 2 As shown, the charging system further includes a controller. When the first end of the first DC-DC converter is connected to the first section of the DC bus and the second end of the first DC-DC converter is connected to the first electric vehicle, the controller is configured to control the states of the p-1 first switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle; wherein, the first electric vehicle is one of the at least one electric vehicle, the first DC-DC converter is any one of the m DC-DC converters, and the first section of the DC bus is the DC bus connected to the first DC-DC converter among the p DC buses.

[0061] A controller is a device with control capabilities. Exemplarily, the controller may include a microcontroller unit (MCU).

[0062] In the embodiment of the present application, the first DC-DC converter takes Figure 2 DC-DC1 as an example, the first section of the DC bus takes Figure 2 DC bus section 1 as an example, and the first electric vehicle takes Figure 2 electric vehicle 1 as an example.

[0063] The controller can control the operating state and the output voltage of each AC-DC converter among the n AC-DC converters. The controller can also control the operating state and the output voltage of each DC-DC converter among the m DC-DC converters. The controller can also control the operating state and the output voltage of each DC-DC converter in the second DC-DC module.

[0064] The controller can adjust the voltage of the first section of the DC bus according to the required voltage of the first electric vehicle so that the operating efficiency of the first DC-DC converter is greater than a set efficiency threshold. Exemplarily, the controller can control the voltage output by AC-DC1, thereby controlling the voltage of DC bus section 1. The set efficiency threshold can be set in advance and can be stored as a parameter in the memory of the controller (such as a non-volatile memory). Exemplarily, the set efficiency threshold can be set to 90%.

[0065] In the embodiment of the present application, when the output voltage of the DC-DC converter is determined, the operating efficiency of the DC-DC converter can be controlled to work in the optimal efficiency state by adjusting the magnitude of the input voltage of the DC-DC converter, thereby improving the operating efficiency of the DC-DC converter and further improving the efficiency of the charging system.

[0066] Optionally, the controller is further configured to adjust the voltage of the first section of the DC bus according to the required voltage of the first electric vehicle.

[0067] Specifically, the controller is further configured to control the states of the p-1 first switches, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle.

[0068] When the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle, the controller is further configured to adjust the voltage of the first section of the DC bus according to the required voltage of the first electric vehicle, so that the first DC-DC converter operates in an optimal efficiency state.

[0069] In the embodiments of the present application, the state of the first switch may include an on state or an off state. When the states of the p-1 first switches are all in the off state, the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is the sum of the powers of at least one DC-DC converter connected to the first section of the DC bus.

[0070] The sum of the powers of at least one DC-DC converter connected to the first electric vehicle refers to the sum of the currently available powers of at least one DC-DC converter connected to the first electric vehicle, that is, the sum of the powers of at least one DC-DC converter currently available for charging the first electric vehicle. Exemplarily, if the power upper limit output by each AC-DC converter is 100 kilowatts, if the first section of the DC bus is connected to 1 AC-DC converter, and the number of electric vehicles connected to the first section of the DC bus through the DC-DC converter is 1 (i.e., the first electric vehicle), then the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is 100 kilowatts. If the first section of the DC bus is connected to 5 AC-DC converters (the first electric vehicle can be connected to 5 AC-DC converters by controlling the states of p-1 first switches), and the number of electric vehicles connected to the first section of the DC bus through the DC-DC converter is 1 (i.e., the first electric vehicle), then the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is 500 kilowatts. If the first electric vehicle is connected to 1 AC-DC converter, and the number of electric vehicles connected to the first section of the DC bus through the DC-DC converter is 2, that is, the first electric vehicle and another electric vehicle, if the other electric vehicle has taken 40 kilowatts of power, then the sum of the available powers of at least one DC-DC converter connected to the first electric vehicle is 60 (100 minus 40) kilowatts. If the first section of the DC bus is connected to 5 AC-DC converters, and the number of electric vehicles connected to the first section of the DC bus through the DC-DC converter is 2, that is, the first electric vehicle and another electric vehicle, if the other electric vehicle has taken 200 kilowatts of power, then the sum of the available powers of at least one DC-DC converter connected to the first electric vehicle is 300 (500 minus 200) kilowatts.

[0071] Exemplarily, if the power upper limit of each AC-DC converter output is 100 kW, if the first section of the DC bus is connected to 1 AC-DC converter, and the number of electric vehicles connected to the first section of the DC bus through the DC-DC converter is 1 (i.e., the first electric vehicle), and the power demand of the first electric vehicle is 100 kW, then all the first switches connected to the first section of the DC bus can be controlled to be in the off state, so that the sum of the available powers of at least one DC-DC converter connected to the first electric vehicle (100 kW) is equal to the power demand of the first electric vehicle (100 kW). If the first section of the DC bus is connected to 1 AC-DC converter, and the number of electric vehicles connected to the first section of the DC bus through the DC-DC converter is 1 (i.e., the first electric vehicle), and the power demand of the first electric vehicle is 200 kW, then one of the first switches connected to the first section of the DC bus can be controlled to be in the on state, so that the first section of the DC bus is connected to the second adjacent section of the DC bus. If the second section of the DC bus is connected to 1 AC-DC converter, and the number of electric vehicles connected to the second section of the DC bus through the DC-DC converter is 0, so that the sum of the available powers of at least one DC-DC converter connected to the first electric vehicle is 200 kW, equal to the power demand of the first electric vehicle.

[0072] The sum of the powers of at least one DC-DC converter connected to the first electric vehicle is related to the states of p - 1 first switches and the power of the load already connected to the first section of the DC bus.

[0073] When the first switch connected to the first section of the DC bus is in the on state, the sum of the powers of at least one DC-DC converter connected to the first electric vehicle increases.

[0074] Exemplarily, if the first switch Ka1 is in the on state, the number of DC-DC converters connected to the electric vehicle 1 increases, so that the sum of the powers of the DC-DC converters connected to the electric vehicle 1 increases.

[0075] It should be noted that when all p - 1 first switches are in the off state, the voltage of each section of the DC bus can be freely adjusted.

[0076] Exemplarily, if Figure 2The power upper limit provided by the shown AC-DC1 and DC-DC1 is 100 kW, while the power demand of the electric vehicle 1 is 400 kW. Therefore, the power provided by AC-DC1 and DC-DC1 cannot meet the demand of the electric vehicle 1. At this time, the outputs of the four DC-DCs, namely DC-DC1, DC-DC2, DC-DC3, and DC-DC4, can be connected in parallel to charge the electric vehicle 1 (here it is default that the power upper limits of AC-DC2 and DC-DC2, AC-DC3 and DC-DC3, and AC-DC4 and DC-DC4 are all 100 kW) to meet the power demand of the electric vehicle 1.

[0077] Optionally, the controller is further configured to control the states of the p - 1 first switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, including:

[0078] When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power demand of the first electric vehicle, the controller is further configured to control the p - 1 first switches to be all in the off state so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle;

[0079] When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, the controller is further configured to control at least one of the p - 1 first switches to be in the on state so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0080] In the embodiment of the present application, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power demand of the first electric vehicle, single-path grid energy replenishment can meet the demand of the first electric vehicle. At this time, the p - 1 first switches are all in the off state, and it can also make the sum of the powers of at least one DC-DC converter connected to the first electric vehicle greater than or equal to the power demand of the first electric vehicle. When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, control at least one of the p - 1 first switches to be in the on state so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0081] Optionally, the controller is further configured to control at least one of the p - 1 first switches to be in an on state, so that the sum of the powers of at least one DC - DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, including:

[0082] The controller is further configured to control the p - 1 first switches to be in an on state in sequence according to the priority from high to low until the sum of the powers of at least one DC - DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle; wherein, the priority of the first switch is negatively correlated with the number of switches passed by the first section of the DC bus.

[0083] The controller is further configured to control the p - 1 first switches to be in an on state in sequence according to the priority from high to low until the sum of the powers of at least one DC - DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0084] Exemplarily, taking the DC bus section 1 in Figure 2 as an example of the first section of the DC bus, and taking the electric vehicle 1 in Figure 2 as an example of the first electric vehicle. If Figure 2 shows that the power upper limits provided by AC - DC1 and DC - DC1 are 100 kW, the power upper limits provided by AC - DC2 and DC - DC2 are 100 kW, the power upper limits provided by AC - DC3 and DC - DC3 are 100 kW, and the power demand of the electric vehicle 1 is 300 kW, then the power provided by AC - DC1 and DC - DC1 cannot meet the demand of the electric vehicle 1. If no other electric vehicles are connected to the DC bus section 2 and the DC bus section 3, at this time, the first switch ka1 and the second switch ka2 can be closed so that the sum of the currently available powers of at least one DC - DC converter connected to the electric vehicle 1 is equal to the power demand of the electric vehicle 1. If other electric vehicles are connected to the DC bus section 2 and the DC bus section 3, at this time, on the basis of closing the first switch ka1 and the first switch ka2, the first switch Ka3 (the first switch Ka3 is the first switch connecting the DC bus section 3 and the DC bus section 4, Figure 2 not shown in Figure 2 ), the first switch ka4 (the first switch Ka4 is the first switch connecting the DC bus section 4 and the DC bus section 5,

[0085] not shown inFigure 2 As shown, the number of switches that the first switch ka1 passes through to reach the DC bus section 1 is 0, the number of switches that the first switch ka2 passes through to reach the DC bus section 1 is 1 (passing through the first switch ka1), and the number of switches that the first switch ka3 passes through to reach the DC bus section 1 is 2 (passing through the first switch ka1 and the first switch ka2). Therefore, the priorities of the first switch ka1, the first switch ka2, and the first switch ka3 decrease in sequence.

[0086] In the embodiment of the present application, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, the controller controls p - 1 first switches to be in the conducting state in sequence according to the priority from high to low until the sum of the currently available powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power demand of the first electric vehicle. On the one hand, the DC bus adjacent to the first section of the DC bus is preferentially made conductive, thus providing a prerequisite for the connection between other DC bus sections not adjacent to the first section of the DC bus and the first section of the DC bus, so that the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus can be gradually increased until the sum of the currently available powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power demand of the first electric vehicle. On the other hand, the fewer the number of switches that the first switch passes through to reach the first section of the DC bus, the lower the switching loss after the first switch is turned on.

[0087] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of another charging system provided by the embodiment of the present application. Figure 3 It is obtained based on Figure 2 , and this charging system further includes a switch unit, and the second ends of the m DC-DC converters are connected to at least one electric vehicle through the switch unit.

[0088] In the embodiments of the present application, the switching unit may include a switching matrix, which enables each of the m DC-DC converters to be connected to each electric vehicle through a switch in the switching matrix. The switching unit can be used for power distribution. Exemplarily, if the power provided by AC-DC1 and DC-DC1 is 100 kW, while the power demand of electric vehicle 1 is 400 kW, therefore, the power provided by AC-DC1 and DC-DC1 cannot meet the demand of electric vehicle 1. At this time, the outputs of four DC-DC converters, namely DC-DC1, DC-DC2, DC-DC3, and DC-DC4, can be connected in parallel to charge electric vehicle 1 (here it is default that the power provided by AC-DC2 and DC-DC2, the power provided by AC-DC3 and DC-DC3, and the power provided by AC-DC4 and DC-DC4 are all 100 kW).

[0089] For the specific structure of the switching unit, reference can be made to the following Figures 4 to 7 .

[0090] Optionally, the second DC-DC module includes k second DC-DC converters. Each energy storage module is connected to one section of the DC bus through the second DC-DC module and / or each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module, including any one of the following four connection methods:

[0091] Connection method 1: Each energy storage module is connected to one section of the DC bus through one of the k second DC-DC converters and one of the k second switches;

[0092] Connection method 2: Each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module;

[0093] Connection method 3: Each energy storage module is connected to one section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module;

[0094] Connection method 4: Each energy storage module is connected to one section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module and q third switches (as Figure 7 shown, Figure 7One of them (taking q = 4 as an example) is connected to the second end of one of the m DC-DC converters, where q is a positive integer less than or equal to k.

[0095] Please refer to Figure 4 , Figure 4 which is a schematic structural diagram of another charging system provided by an embodiment of the present application. Figure 4 It is obtained based on Figure 3 and is a charging system according to the above connection method 1. Figure 4 Taking n = p = m = 4 as an example. As Figure 4 shown, 4 energy storage modules (such as the energy storage module 1, energy storage module 2, energy storage module 3, and energy storage module 4 shown in Figure 4 ) are respectively and correspondingly connected to 4 DC bus segments through 4 second DC-DC converters (such as DC-DC_1, DC-DC_2, DC-DC_3, and DC-DC_4 shown in Figure 4 ) and 4 second switches (such as Kb1, Kb2, Kb3, and Kb4 shown in Figure 4 ). There is a connection between DC bus segment 1 and DC bus segment 2 through the first switch Ka1, a connection between DC bus segment 2 and DC bus segment 3 through the first switch Ka2, and a connection between DC bus segment 3 and DC bus segment 4 through the first switch Ka3. Figure 4 The switch unit may include a switch matrix. As

[0096] shown, the switch unit includes 14 switches. Electric vehicle 1 is connected to DC-DC1, DC-DC2, DC-DC3, and DC-DC4 through 4 switches respectively. Electric vehicle 2 is connected to DC-DC1, DC-DC2, DC-DC3, and DC-DC4 through 4 switches respectively. Electric vehicle 3 is connected to DC-DC2, DC-DC3, and DC-DC4 through 3 switches respectively. Electric vehicle 4 is connected to DC-DC2, DC-DC3, and DC-DC4 through 3 switches respectively. It should be noted that Figure 4 is a possible example of the switch unit. The number of switches connected to each electric vehicle may be less than or equal to the number of DC-DC converters in the first DC-DC module. Figure 4 The controller can control the switch unit to perform power distribution. Exemplarily, if the power provided by AC-DC1 and DC-DC1 is 100 kilowatts, while the power demand of electric vehicle 1 is 400 kilowatts. Therefore, the power provided by AC-DC1 and DC-DC1 cannot meet the demand of electric vehicle 1. At this time, the outputs of these four DC-DCs, namely DC-DC1, DC-DC2, DC-DC3, and DC-DC4, can be paralleled (for example,

[0097] ). Figure 4In the switching unit, all 4 switches connected to Electric Vehicle 1 are closed, and all switches connected to Electric Vehicle 2, Electric Vehicle 3, and Electric Vehicle 4 are opened), to charge Electric Vehicle 1 (here it is default that the power provided by AC-DC2 and DC-DC2, the power provided by AC-DC3 and DC-DC3, and the power provided by AC-DC4 and DC-DC4 are all 100 kilowatts).

[0098] In the embodiments of the present application, when the energy storage module needs to be charged, the controller can control the DC-DC converter connected to the energy storage module to charge the energy storage module. When the energy storage module needs to discharge, the controller can control the DC-DC converter connected to the energy storage module to discharge to the DC bus.

[0099] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of another charging system provided by the embodiments of the present application. Figure 5 It is obtained based on Figure 3 , Figure 5 and is a charging system according to the above connection method 2. Figure 5 Taking n = p = m = 4 as an example, Figure 5 the specific structure of the switching unit of Figure 4 can be referred to Figure 5 . As shown in Figure 5 , 4 energy storage modules (such as the energy storage module 1, energy storage module 2, energy storage module 3, and energy storage module 4 shown in Figure 4 ) are respectively connected to the second ends of 4 DC-DC converters (such as DC-DC_1, DC-DC_2, DC-DC_3, and DC-DC_4 shown in Figure 4 ) through 4 second DC-DC converters. A first switch Ka1 is connected between DC bus segment 1 and DC bus segment 2, a first switch Ka2 is connected between DC bus segment 2 and DC bus segment 3, and a first switch Ka3 is connected between DC bus segment 3 and DC bus segment 4.

[0100] Please refer to Figure 6 , Figure 6 which is a schematic structural diagram of another charging system provided by the embodiments of the present application. Figure 6 It is obtained based on Figure 3 , Figure 6 and is a charging system according to the above connection method 3. Figure 6 Taking n = p = m = 4 as an example, Figure 6 the specific structure of the switching unit of Figure 4 can be referred to Figure 6The energy storage modules 1, 2, 3, and 4 shown are respectively connected to four DC bus segments through four second DC-DC converters (such as Figure 4 the DC-DC_1, DC-DC_2, DC-DC 3, and DC-DC4 shown) and four second switches (such as Figure 4 the Kb1, Kb2, Kb3, and Kb4 shown). The four energy storage modules are respectively connected to the second ends of four DC-DC converters (such as Figure 4 the DC-DC_1, DC-DC_2, DC-DC_3, and DC-DC_4 shown) through four second DC-DC converters (such as Figure 4 the DC-DC1, DC-DC2, DC-DC3, and DC-DC4 shown). The DC bus segment 1 and the DC bus segment 2 are connected through the first switch Ka1, the DC bus segment 2 and the DC bus segment 3 are connected through the first switch Ka2, and the DC bus segment 3 and the DC bus segment 4 are connected through the first switch Ka3.

[0101] Please refer to Figure 7 , Figure 7 which is a schematic structural diagram of another charging system provided by an embodiment of the present application. Figure 7 is obtained on the basis of Figure 3 , Figure 7 and is a charging system according to the above connection method 4. Figure 7 Taking n = p = q = m = 4 as an example, Figure 7 the specific structure of the switch unit of Figure 4 can be referred to Figure 7 . As shown in Figure 7 , four energy storage modules (such as Figure 4 the energy storage modules 1, 2, 3, and 4 shown) are respectively connected to four DC bus segments through four second DC-DC converters (such as Figure 4 the DC-DC_1, DC-DC_2, DC-DC_3, and DC-DC_4 shown) and four second switches (such as Figure 4 the Kb1, Kb2, Kb3, and Kb4 shown). The four energy storage modules are respectively connected to four DC-DC converters (such as Figure 4 the Kc1, Kc2, Kc3, and Kc4 shown) and four third switches (such as Figure 4The second ends of the shown DC-DC1, DC-DC2, DC-DC3, and DC-DC4 are connected in one-to-one correspondence. The DC bus section 1 and the DC bus section 2 are connected through the first switch Ka1, the DC bus section 2 and the DC bus section 3 are connected through the first switch Ka2, and the DC bus section 3 and the DC bus section 4 are connected through the first switch Ka3.

[0102] Optionally, when each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and when the first energy storage module needs to be charged, the controller is configured to control the second switch connected in one-to-one correspondence with the first energy storage module to be in the on state, so that the AC power grid charges the first energy storage module, and the first energy storage module is any one of the k energy storage modules.

[0103] Exemplarily, as Figure 4 shown, when the energy storage module 1 needs to be charged, the controller can control Kb1 to be in the on state, and control DC-DC_1 to convert the direct current on the DC bus section 1 into the charging voltage of the energy storage module 1, so as to charge the energy storage module 1. When the energy storage module 1 needs to discharge, Kb1 can be controlled to be in the on state, and DC-DC_1 can be controlled to convert the voltage output by the energy storage module 1 into the voltage of the DC bus section 1, so as to realize the discharge of the energy storage module 1 to the DC bus section 1.

[0104] Optionally, the controller is further configured to adjust the voltage of the first section of the DC bus according to the required voltage of the first electric vehicle, including:

[0105] The controller is further configured to control the states of the p-1 first switches, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle;

[0106] When the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle, the controller is further configured to adjust the voltage of the first section of the DC bus according to the required voltage of the first electric vehicle, so that the first DC-DC converter operates in the optimal efficiency state.

[0107] In the embodiment of the present application, the first section of the DC bus takes Figure 4 the DC bus section 1 in Figure 4The power upper limit provided by the shown AC-DC1 is 100 kW, the power upper limit provided by DC-DC1 is 200 kW, the power upper limit provided by AC-DC2 is 100 kW, the power upper limit provided by DC-DC2 is 200 kW, the power upper limit provided by AC-DC3 is 100 kW, the power upper limit provided by DC-DC3 is 200 kW, and the power provided by the DC-DC converter connected to each of the 4 energy storage modules is 100 kW. The power demand of Electric Vehicle 1 is 200 kW. Therefore, the power provided by AC-DC1 cannot meet the demand of Electric Vehicle 1. At this time, any one of the following three methods can be adopted to make the sum of the powers of at least one DC-DC converter connected to Electric Vehicle 1 greater than or equal to the power demand of Electric Vehicle 1:

[0108] (1) Close the first switch Ka1 to parallel the outputs of these two AC-DCs, namely AC-DC1 and AC-DC2, and charge Electric Vehicle 1 through DC-DC1.

[0109] (2) Close the second switch Kb1 to parallel the outputs of these two paths, namely AC-DC1 and DC-DC_1, and charge Electric Vehicle 1 through DC-DC1.

[0110] (3) Close the first switch Ka1 and the second switch Kb1 to parallel the outputs of these three paths, namely AC-DC1, AC-DC2, and DC-DC_1, and charge Electric Vehicle 1 through DC-DC1. At this time, the controller can control the total power of the outputs of these three paths to be 200 kW.

[0111] Optionally, the controller is further configured to control the p - 1 first switches and the k second switches to be in the off state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0112] Optionally, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is greater than or equal to the power demand of the first electric vehicle, the controller is further configured to control the k second switches to be in the off state, and control at least one of the p - 1 first switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle;

[0113] When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is less than the power demand of the first electric vehicle, the controller is further configured to control all the p-1 first switches to be in the on state and at least one of the k second switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. In the embodiments of the present application, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power demand of the first electric vehicle, single-grid energy replenishment can meet the demand of the first electric vehicle. At this time, the p-1 first switches and the k second switches are all in the off state, and it is also possible to make the sum of the powers of at least one DC-DC converter connected to the first electric vehicle greater than or equal to the power demand of the first electric vehicle. When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is greater than or equal to the power demand of the first electric vehicle, the controller controls all the p-1 first switches to be in the on state and at least one of the k second switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0114] Optionally, the controller is further configured to control the k second switches to be in the off state and at least one of the p-1 first switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, including:

[0115] The controller is further configured to control the k second switches to be in the off state and control the p-1 first switches to be in the on state in order from the highest priority to the lowest priority until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle; wherein, the priority of the first switch is negatively correlated with the number of switches passed by the first switch to the first section of the DC bus.

[0116] In an embodiment of the present application, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is greater than or equal to the power demand of the first electric vehicle, the controller controls the k second switches to be in the off state, and controls the p-1 first switches to be in the on state in order from highest to lowest priority until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. When the capacity of the AC grid can meet the charging power demand of the first electric vehicle, all Kb switches are turned off, and only the number of Ka switches turned on needs to be controlled to meet the charging demand of the vehicle.

[0117] Optionally, the controller is further configured to control the p-1 first switches to be in the on state, and control at least one of the k second switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, including:

[0118] The controller is further configured to control the p-1 first switches to be in the on state, and control the k second switches to be in the on state in order from highest to lowest priority until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle; wherein, the priority of the second switch is negatively correlated with the number of switches passed by the second switch to the first section of the DC bus.

[0119] When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is less than the power demand of the first electric vehicle, the controller is further configured to control the p-1 first switches to be in the on state, and control the k second switches to be in the on state in order from highest to lowest priority until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. When the capacity of the AC grid cannot meet the charging power demand of the first electric vehicle, when all Ka switches are closed, the Kb switch is closed, and the energy storage module is connected to the first section of the DC bus through the second DC-DC module to supply energy to the first electric vehicle.

[0120] Exemplarily, the first section of the DC bus takes Figure 4 the DC bus section 1 therein as an example, and the first electric vehicle takes Figure 4 the electric vehicle 1 therein as an example. If Figure 4The power upper limit provided by the shown AC-DC1 is 100 kW, the power upper limit provided by DC-DC1 is 200 kW, the power upper limit provided by AC-DC2 is 100 kW, the power upper limit provided by DC-DC2 is 200 kW, the power upper limit provided by AC-DC3 is 100 kW, and the power upper limit provided by DC-DC3 is 200 kW. If the power demand of the electric vehicle 1 is 200 kW, the power provided by AC-DC1 cannot meet the demand of the electric vehicle 1. If no electric vehicle is connected to the DC busbar 2, the first switch ka1 can be closed at this time, so that the sum of the powers of at least one DC-DC converter connected to the electric vehicle 1 is equal to the power demand of the electric vehicle 1. If other electric vehicles are connected to the DC busbar 2, on the basis of closing the first switch ka1, the first switch Ka2, the first switch Ka3, etc. can be continuously closed in sequence until the sum of the powers of at least one DC-DC converter connected to the electric vehicle 1 is greater than or equal to the power demand of the electric vehicle 1. At this time, since the dispatchable power of the AC grid is greater than or equal to the power demand of the electric vehicle 1, the k second switches are in the off state.

[0121] If the dispatchable power of the AC grid is less than the power demand of the electric vehicle 1, all the first switches are closed (i.e., all the first switches are in the on state), and the k second switches are controlled to be in the on state in sequence according to the priority from high to low until the sum of the powers of at least one DC-DC converter connected to the electric vehicle 1 is greater than or equal to the power demand of the electric vehicle 1.

[0122] Among them, the priority of the first switch is negatively correlated with the number of switches passed by the first switch to the first section of the DC bus. As Figure 4 shown, the number of switches passed by the first switch Ka1 to the DC busbar 1 is 0, the number of switches passed by the first switch Ka2 to the DC busbar 1 is 1 (passing through the first switch Ka1), and the number of switches passed by the first switch Ka3 to the DC busbar 1 is 2 (passing through the first switch Ka1 and the first switch Ka2). Therefore, the priorities of the first switch Ka1, the first switch Ka2, and the first switch Ka3 decrease in sequence.

[0123] The priority of the second switch is negatively correlated with the number of switches passed by the second switch to the first section of the DC bus. As Figure 4 shown, the number of switches passed by the second switch Kb1 to the DC busbar 1 is 0, the number of switches passed by the second switch Kb2 to the DC busbar 1 is 1 (passing through the second switch Ka1), and the number of switches passed by the second switch Kb3 to the DC busbar 1 is 2 (passing through the second switch Ka1 and the second switch Ka2). Therefore, the priorities of the second switch Kb1, the second switch Kb2, and the second switch Kb3 decrease in sequence.

[0124] In an embodiment of the present application, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is greater than or equal to the power demand of the first electric vehicle, the controller controls the k second switches to be in the off state, and controls p - 1 first switches to be in the on state in order from the highest priority to the lowest priority until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. On the one hand, the DC bus adjacent to the first section of the DC bus is preferentially turned on, thus providing a prerequisite for the connection between other DC buses not adjacent to the first section of the DC bus and the first section of the DC bus, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle can be gradually increased until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. On the other hand, the fewer the number of switches that the first switch passes through to reach the first section of the DC bus, the lower the switching loss after the first switch is turned on.

[0125] When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, and the dispatchable power of the AC grid is less than the power demand of the first electric vehicle, the controller controls p - 1 first switches to be in the on state, and controls k second switches to be in the on state in order from the highest priority to the lowest priority until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. The second switch with fewer switches passing through to the first section of the DC bus is preferentially closed. The fewer the number of switches that the second switch passes through to reach the first section of the DC bus, the lower the switching loss after the second switch is turned on.

[0126] In an embodiment of the present application, since there are two DC-DC converters from the energy storage module to the first electric vehicle, the charging efficiency of the energy storage module for the first electric vehicle is relatively low. The AC grid is preferentially used for power supply. When the capacity of the AC grid cannot meet the charging power demand of the first electric vehicle, the energy storage module is added for power supply, so as to improve the efficiency of the charging system as much as possible.

[0127] When the energy storage module needs to be charged, the controller can control the second switches (such as Figure 7 Kb1, Kb2, Kb3, Kb4 shown) to be turned on, and control the third switches (such as Figure 7 the third switches Kc1, Kc2, Kc3, Kc4 shown) to be turned off, so as to control the AC grid to charge the energy storage module. When the energy storage module needs to discharge, the controller can control the second switches (such as Figure 7Kb1, Kb2, Kb3, Kb4) shown in FIG. 1 are disconnected, and the third switch (such as Figure 7 The third switch Kc1, Kc2, Kc4) shown is turned on, thereby controlling the energy storage module to charge the electric vehicle.

[0128] The first ends of the k DC-DC converters in the second DC-DC module are respectively connected to the k energy storage modules, the second ends of the k DC-DC converters are respectively connected to the k second switches, and the second ends of the q DC-DC converters in the k DC-DC converters are respectively connected to the q third switches.

[0129] Optionally, when each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module, the controller is further used to control the states of the p-1 first switches and the states of the q third switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0130] Optionally, when the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, the controller is further used to adjust the voltage of the first section of the DC bus according to the required voltage of the first electric vehicle so that the first DC-DC converter operates at an optimal efficiency state.

[0131] In the embodiment of the present application, the first section of the DC bus is Figure 7 For example, if the DC bus segment 1 in Figure 7 As shown, the power upper limits provided by AC-DC1 and DC-DC1 are both 100 kilowatts, the power upper limits provided by AC-DC2 and DC-DC2 are both 100 kilowatts, and the power upper limits provided by AC-DC3 and DC-DC3 are both 100 kilowatts. The power provided by the DC-DC converter connected to each of the k energy storage modules is 100 kilowatts, while the power demand of the electric vehicle 1 is 200 kilowatts. Therefore, the power provided by AC-DC1 and DC-DC1 cannot meet the demand of the electric vehicle 1. At this time, the third switch Kc1 can be closed to connect the outputs of the two DC-DCs, DC-DC1 and DC-DC_1, in parallel to charge the electric vehicle 1.

[0132] Figure 7 and Figure 4 In comparison, electric cars require 200 kilowatts to charge. Figure 4 The power ceiling of the DC-DC1 needs to be 200 kW.Figure 7 The electric vehicle 1 can be charged by the DC-DC_1 of the energy storage module 1 and the DC-DC1 of the AC power grid, and both the DC-DC_1 and the DC-DC1 only require a power upper limit of 100 kW. Compared with Figure 4 compared with Figure 7 , the power of each DC-DC converter is reduced, thereby reducing the cost of the charging system and the volume of the charging system.

[0133] It should be noted that Figure 7 Although the third switch is added, due to the reduction of the power of the DC-DC converter, the cost of the DC-DC converter is reduced. Compared with the cost increase of the third switch, the cost reduction of the DC-DC converter is more. Compared with Figure 4 , Figure 7 , the charging system has a lower cost and a smaller volume. In addition, compared with Figure 4 , Figure 7 , when the energy storage module of

[0134] charges the electric vehicle, it only needs to go through one DC-DC converter, and the energy conversion efficiency is higher. Figure 7 It should be noted that Figure 7 when charging the electric vehicle, Figure 7 the second switch of

[0135] is in the off state. When the second switch of

[0136] is in the on state, the AC power grid is used to charge the energy storage module.

[0137] Optionally, the controller is further configured to control the states of the p-1 first switches and the q third switches, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle, including:

[0138] When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power requirement of the first electric vehicle, the controller is further configured to control both the p-1 first switches and the q third switches to be in the off state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle; When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power requirement of the first electric vehicle, the controller is further configured to control at least one of the p-1 first switches and the q third switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power requirement of the first electric vehicle.

[0138] In an embodiment of the present application, when the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is greater than or equal to the power demand of the first electric vehicle, single-path grid energy replenishment can meet the demand of the first electric vehicle. At this time, p-1 first switches and q third switches are all in the off state, and it is also possible to make the current schedulable power of the first section of the DC bus greater than or equal to the power demand of the first electric vehicle. When the sum of the powers of at least one AC-DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, the controller controls at least one of the p-1 first switches and the q third switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

[0139] Optionally, the controller is further configured to control at least one of the p-1 first switches and the q third switches to be in the on state, so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle, including:

[0140] The controller is further configured to control the p-1 first switches and the q third switches to be in the on state in sequence according to the priority from high to low until the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle; wherein, the priority of the first switch is negatively correlated with the number of switches passed by the first switch to the first section of the DC bus, and the priority of the third switch is negatively correlated with the number of switches passed by the third switch to the second end of the first DC-DC converter.

[0141] Exemplarily, the first section of the DC bus takes Figure 7 the DC bus section 1 therein as an example, and the first electric vehicle takes Figure 7 the electric vehicle 1 therein as an example. If Figure 7The upper power limit provided by the shown AC-DC1 is 100 kW, the upper power limit provided by DC-DC1 is 100 kW, the upper power limit provided by AC-DC2 is 100 kW, the upper power limit provided by DC-DC2 is 100 kW, the upper power limit provided by AC-DC3 is 100 kW, the upper power limit provided by DC-DC3 is 100 kW. If the power demand of the electric vehicle 1 is 200 kW, the power provided by AC-DC1 cannot meet the demand of the electric vehicle 1. If the energy storage module 1 can provide energy, the third switch kc1 can be closed to parallel the outputs of these two DC-DCs, namely DC-DC1 and DC-DC_1, to charge the electric vehicle 1. If the energy storage module 1 cannot provide energy (for example, the energy of the energy storage module 1 is exhausted or lower than the set minimum allowable discharge energy threshold), the energy storage module 2 can charge the electric vehicle 1 through DC-DC_2 by closing the third switch kc2. Specifically, the energy path for the energy storage module 2 to charge the electric vehicle 1 is: energy storage module 2 → DC-DC_2 → the second terminal of DC-DC2 → the second terminal of DC-DC1 → electric vehicle 1. At this time, the second terminal of DC-DC2 and the second terminal of DC-DC1 can be connected through the switch in the switch unit. If neither the energy storage module 1 nor the energy storage module 2 can provide energy, the energy storage module 3 can charge the electric vehicle 1 through DC-DC_3 by closing the third switch kc3.

[0142] Exemplarily, the first section of the DC bus takes Figure 7 the DC bus section 1 therein as an example, and the first electric vehicle takes Figure 7 the electric vehicle 1 therein as an example. If Figure 7The power upper limit provided by the shown AC-DC1 is 100 kW, the power upper limit provided by DC-DC1 is 200 kW, the power upper limit provided by AC-DC2 is 100 kW, the power upper limit provided by DC-DC2 is 200 kW, the power upper limit provided by AC-DC3 is 100 kW, and the power upper limit provided by DC-DC3 is 200 kW. If the power demand of the electric vehicle 1 is 200 kW, the power provided by AC-DC1 cannot meet the demand of the electric vehicle 1. If the energy storage module 1 can provide energy, the third switch kc1 can be closed to parallel the outputs of DC-DC1 and DC-DC_1, these two DC-DCs, to charge the electric vehicle 1. If the energy storage module 1 cannot provide energy (for example, the energy of the energy storage module 1 is exhausted or lower than the set minimum allowable discharge energy threshold), the power sum of at least one DC-DC converter connected to the electric vehicle 1 can be made equal to the power demand of the electric vehicle 1 by closing the first switch ka1. If other electric vehicles are connected to the DC bus section 2, at this time, on the basis of closing the first switch ka1, the first switch Ka2, the first switch Ka3, etc. can be sequentially closed until the power sum of at least one DC-DC converter connected to the electric vehicle 1 is greater than or equal to the power demand of the electric vehicle 1.

[0143] Wherein, the priority of the third switch is negatively correlated with the number of switches passed by the first section of the third switch to the DC bus. As Figure 7 shown, the number of switches passed by the third switch Kc1 to the second end of DC-DC1 is 0, the number of switches passed by the third switch Kc2 to the second end of DC-DC1 is 1 (passing through the third switch Ka1), and the number of switches passed by the third switch Kc3 to the second end of DC-DC1 is 2 (passing through the third switch Ka1 and the third switch Ka2). Therefore, the priorities of the third switch Kc1, the third switch Kc2, and the third switch Kc3 decrease in turn.

[0144] Wherein, the priority of the first switch is negatively correlated with the number of switches passed by the first section of the first switch to the DC bus. As Figure 7 shown, the number of switches passed by the first switch Ka1 to the DC bus section 1 is 0, the number of switches passed by the first switch Ka2 to the DC bus section 1 is 1 (passing through the first switch Ka1), and the number of switches passed by the first switch Ka3 to the DC bus section 1 is 2 (passing through the first switch Ka1 and the first switch Ka2). Therefore, the priorities of the first switch Ka1, the first switch Ka2, and the first switch Ka3 decrease in turn.

[0145] Among them, the priorities of the first switch and the third switch can be preset. Exemplarily, it can be set that the priorities of p - 1 first switches are all greater than those of q third switches, or it can be set that the priorities of p - 1 first switches are all less than those of q third switches, or it can be set that among the p - 1 first switches, there is a first switch whose priority is greater than that of at least one of the q third switches, and among the p - 1 first switches, there is a first switch whose priority is less than that of at least one of the q third switches.

[0146] In the embodiment of the present application, when the sum of the powers of at least one AC - DC converter connected to the first section of the DC bus is less than the power demand of the first electric vehicle, the controller controls the p - 1 first switches and the q third switches to be in the on state in order of decreasing priority until the sum of the powers of at least one DC - DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. In one embodiment, the third switch can be preferentially turned on to supply power to the electric vehicle by the energy storage module, thereby reducing the power upper limit of each DC - DC converter, reducing the cost of the DC - DC converter, and thus reducing the cost of the charging system and the volume of the charging system. When preferentially turning on the third switch, the third switch with a higher priority is preferentially turned on. In another embodiment, the first switch can be preferentially turned on to conduct the DC bus adjacent to the first section of the DC bus, thereby providing a prerequisite for the connection between other DC buses not adjacent to the first section of the DC bus and the first section of the DC bus, and thus gradually increasing the currently schedulable power of the first section of the DC bus until the sum of the powers of at least one DC - DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle. When preferentially turning on the first switch, the first switch with a higher priority is preferentially turned on.

[0147] Optionally, the sum of the powers of at least one DC - DC converter connected to each electric vehicle is greater than or equal to the power demand of each electric vehicle. The charging system of the embodiment of the present application can meet the power demand of each electric vehicle. The state of each first switch, each second switch, and each third switch can be controlled by the controller, so as to schedule the number of DC - DC converters connected to each electric vehicle, and further make the sum of the powers of at least one DC - DC converter connected to each electric vehicle greater than or equal to the power demand of each electric vehicle.

[0148] Please refer to Figure 8 , Figure 8 which is a schematic structural diagram of a charging station provided by the embodiment of the present application. As Figure 8 shown, the charging station may include any one of the charging systems as Figures 1 to 7 described above.

[0149] In the above embodiments, the descriptions of the various embodiments each have their own emphasis. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0150] In several embodiments provided by the present application, it should be understood that the disclosed charging system can be implemented in other ways. For example, the charging system embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

Claims

1. A charging system, characterized in that: The invention comprises an AC-DC module, a first DC-DC module, a second DC-DC module, a DC bus and k energy storage modules, wherein the AC-DC module comprises n AC-DC converters, the first DC-DC module comprises m DC-DC converters, and the DC bus comprises a plurality of sections which can be connected and disconnected in sequence; the input ends of the n AC-DC converters are connected to an AC power grid, the output ends of the n AC-DC converters are respectively connected to a section of the DC bus, each section of the DC bus is connected to the output end of at least one AC-DC converter, the first ends of the m DC-DC converters are respectively connected to a section of the DC bus, each section of the DC bus is connected to the first end of at least one DC-DC converter among the m DC-DC converters, and the second ends of the m DC-DC converters are used to connect to at least one electric vehicle; each energy storage module is connected to a section of the DC bus through the second DC-DC module and / or each energy storage module is connected to the second end of one DC-DC converter among the m DC-DC converters through the second DC-DC module; m, n, and p are all integers greater than or equal to 2, k is an integer greater than or equal to 1, p is less than or equal to n, p is less than or equal to m, and k is less than or equal to p.

2. The charging system according to claim 1, characterized in that: The sum of the powers of at least one DC-DC converter connected to each electric vehicle is greater than or equal to the power requirement of each electric vehicle.

3. The charging system according to claim 1, characterized in that: Any two adjacent sections of the DC bus are connected via a first switch.

4. The charging system according to claim 3, characterized in that: When any of the first switches is disconnected, the two voltage sections of the DC bus connected to the disconnected first switch are adjustable.

5. The charging system according to claim 3, characterized in that: When any of the first switches is disconnected, voltages of two sections of the DC bus connected to the disconnected first switch are different.

6. The charging system according to claim 3, characterized in that: When any of the first switches is closed, the voltages of the two sections of the DC bus connected to the closed first switch are the same.

7. The charging system according to claim 3, characterized in that: The DC bus is divided into p sections by p-1 first switches. The charging system also includes a controller. When a first end of a first DC-DC converter is connected to a first section of the DC bus, a second end of the first DC-DC converter is connected to a first electric vehicle, and a voltage of the first section of the DC bus is adjustable, the controller is used to control the states of the p-1 first switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to a power demand of the first electric vehicle; wherein the first electric vehicle is one of the at least one electric vehicle, the first DC-DC converter is any one of the m DC-DC converters, and the first section of the DC bus is a section of the DC bus connected to the first DC-DC converter.

8. The charging system according to claim 7, characterized in that: The second DC-DC module includes k second DC-DC converters, each energy storage module is connected to a section of the DC bus through the second DC-DC module and / or each energy storage module is connected to a second end of one of the m DC-DC converters through the second DC-DC module, including: Each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches; or, Each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module; or, Each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to a second end of one of the m DC-DC converters through the second DC-DC module; or, Each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to a second end of one of the m DC-DC converters through the second DC-DC module and one of the q third switches, where q is a positive integer less than or equal to k.

9. The charging system according to claim 8, characterized in that: The controller is also used to control the states of the p-1 first switches and the states of the k second switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

10. The charging system according to claim 8, characterized in that: In the case where each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and each energy storage module is connected to the second end of one of the m DC-DC converters through the second DC-DC module, the controller is further used to control the states of the p-1 first switches and the states of the q third switches so that the sum of the powers of at least one DC-DC converter connected to the first electric vehicle is greater than or equal to the power demand of the first electric vehicle.

11. The charging system according to claim 8, characterized in that: When each energy storage module is connected to a section of the DC bus through one of the k second DC-DC converters and one of the k second switches, and a first energy storage module needs to be charged, the controller is used to control the second switches connected one-to-one with the first energy storage modules to be in an on state, so that the AC power grid charges the first energy storage module, and the first energy storage module is any one of the k energy storage modules.

12. The charging system according to any one of claims 1 to 11, characterized in that: The charging system further comprises a switch unit, and the second ends of the m DC-DC converters are connected to at least one electric vehicle via the switch unit.

13. The charging system according to any one of claims 1 to 11, characterized in that: The charging system further comprises a photovoltaic assembly, and the photovoltaic assembly is connected to at least one section of the DC bus through a third DC-DC module.

14. A charging station, characterized in that: Comprising a charging system as claimed in any one of claims 1 to 13.

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