Charging circuit and charging system

Abstract

The invention discloses a charging circuit and a charging system, relates to the technical field of power electronics, and aims to realize rapid energy storage of energy storage equipment. The charging circuit comprises a DC bus, an energy storage device, a first DC converter and a second DC converter. The first direct-current converter is connected between the direct-current bus and the electric load, the second direct-current converter is connected between the direct-current bus and the energy storage equipment, the electric load supplies power to the energy storage equipment at least through the first direct-current converter, and / or the direct-current bus supplies power to the energy storage equipment through the second direct-current converter.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a charging circuit and a charging system. Background Art

[0002] With the rapid popularization of electric vehicles and their increasing market share, users' demand for car charging speed has also steadily increased.

[0003] In order to meet the demand for fast charging of electric vehicles, energy storage devices have been introduced into the current charging system. The energy storage devices are connected to the power grid, and power is supplied to electric vehicles through the energy storage devices and the power grid at the same time, thereby speeding up the charging speed.

[0004] When energy storage devices power electric vehicles, they frequently charge and discharge, creating a need for recharging. Because the grid needs to power both the electric vehicles and the energy storage devices, recharging is slow, a problem exacerbated by high grid loads. Summary of the Invention

[0005] The purpose of the present invention is to provide a charging circuit and a charging system, aiming to achieve rapid energy replenishment of energy storage equipment.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a charging circuit comprising a DC bus, an energy storage device, a first DC converter, and a second DC converter. The first DC converter is connected between the DC bus and an electrical load, and the second DC converter is connected between the DC bus and the energy storage device. The electrical load supplies power to the energy storage device at least through the first DC converter, and / or the DC bus supplies power to the energy storage device through the second DC converter.

[0008] In the charging circuit provided in some embodiments of the present application, since the first DC converter is connected between the DC bus and the electrical load, and the second DC converter is connected between the DC bus and the energy storage device, the DC bus can supply power to the electrical load through the first DC converter, and the DC bus can supply power to the energy storage device through the second DC converter. The electrical load supplies power to the energy storage device at least through the first DC converter, and / or the DC bus supplies power to the energy storage device through the second DC converter. This means that while the DC bus supplies power to the energy storage device through the second DC converter, the electrical load can also supply power to the energy storage device through the first DC converter. The energy storage device is transformed from being able to be powered only by the DC bus to being powered by both the electrical load and the DC bus, so that high-power and fast charging can be performed. Since the electrical load can supply power to the energy storage device, the electrical load and the energy storage device are transformed from being independent of each other to being interconnected, thereby realizing the connection and distribution of energy between the loads (electrical loads and energy storage devices).

[0009] In some embodiments, the charging circuit further includes a switching subcircuit connected to the DC bus and respectively connected to the first DC converter, the electrical load, the second DC converter, and the energy storage device. The switching subcircuit is configured to conduct the power path between the first DC converter and the DC bus, and between the DC bus and the second DC converter, so that the electrical load supplies power to the energy storage device via the first DC converter, the DC bus, and the second DC converter.

[0010] In some embodiments, the switch subcircuit is further configured to: conduct an electrical path between the first DC converter and the energy storage device, so as to use the electrical load to supply power to the energy storage device through the first DC converter.

[0011] In some embodiments, the switching subcircuit includes a first input terminal, a second input terminal, a first output terminal, a second output terminal, a third output terminal and a fourth output terminal; the first input terminal and the second input terminal of the switching subcircuit are respectively connected to the DC bus; the first output terminal of the switching subcircuit is connected to the first DC converter, the second output terminal of the switching subcircuit is connected to the energy storage device, the third output terminal of the switching subcircuit is connected to the second DC converter, and the fourth output terminal of the switching subcircuit is connected to the power load.

[0012] In some embodiments, the switch subcircuit includes a first switch, a second switch, a third switch, and a fourth switch; the first end of the first switch is connected to the first input end of the switch subcircuit, the second end of the first switch is connected to the first output end of the switch subcircuit, the first end of the second switch is connected to the first output end of the switch subcircuit, and the second end of the second switch is connected to the second output end of the switch subcircuit; the first end of the third switch is connected to the second input end of the switch subcircuit, the second end of the third switch is connected to the third output end of the switch subcircuit, the first end of the fourth switch is connected to the third output end of the switch subcircuit, and the second end of the fourth switch is connected to the fourth output end of the switch subcircuit.

[0013] In some embodiments, when the energy storage device is charged and the charging power is greater than or equal to the power threshold, the switch subcircuit controls the first switch and the third switch to be closed, and controls the second switch and the fourth switch to be open.

[0014] In some embodiments, when the energy storage device is charged and the charging power is greater than or equal to the power threshold, the switch subcircuit controls the second switch and the third switch to be closed, and controls the first switch and the fourth switch to be open.

[0015] In some embodiments, the power supply source for the electrical load includes at least one of a DC bus and an energy storage device.

[0016] In some embodiments, the switch subcircuit is further configured to: conduct an electrical path between the electrical load and the second DC converter, so that the energy storage device supplies power to the electrical load through the second DC converter.

[0017] In some embodiments, the switch subcircuit is further configured to: conduct the power path between the first DC converter and the DC bus and conduct the power path between the DC bus and the second DC converter, so that the energy storage device supplies power to the electrical load through the second DC converter, the DC bus, and the first DC converter.

[0018] In some embodiments, when the charging power of the electrical load is greater than or equal to the power threshold, the power supply source of the electrical load includes a DC bus and an energy storage device. The switch subcircuit controls the first switch and the fourth switch to be closed, and controls the second switch and the third switch to be open.

[0019] In some embodiments, the switching subcircuit is further configured to: based on the voltage of the DC bus and the voltage of the electrical load, conduct the power path between the DC bus and the first DC converter and the electrical load, or conduct the power path between the electrical load and the DC bus.

[0020] In some embodiments, when the electrical load is being charged and the charging power is less than a power threshold, the switching subcircuit is configured to: conduct a power path between the DC bus and the electrical load if the DC bus voltage is greater than the load voltage; and conduct a power path between the DC bus, the first DC converter, and the load if the DC bus voltage is less than or equal to the load voltage.

[0021] In some embodiments, when the electrical load is discharging, the switching subcircuit is further configured to: conduct a power path between the DC bus, the first DC converter, and the electrical load if the voltage of the DC bus is greater than or equal to the voltage of the electrical load; and conduct a power path between the DC bus and the electrical load if the voltage of the DC bus is less than the voltage of the electrical load.

[0022] In some embodiments, the switching subcircuit is further configured to: based on the voltage of the DC bus and the voltage of the energy storage device, conduct the power path between the DC bus and the second DC converter and the energy storage device, or conduct the power path between the energy storage device and the DC bus.

[0023] In some embodiments, when the energy storage device is being charged and the charging power is less than a power threshold, the switch subcircuit is configured to: conduct a power path between the DC bus and the energy storage device if the DC bus voltage is greater than the energy storage device voltage; and conduct a power path between the DC bus and the second DC converter and the energy storage device if the DC bus voltage is less than or equal to the energy storage device voltage.

[0024] In some embodiments, when the energy storage device is discharging, the switch subcircuit is configured to: conduct a power path between the DC bus and the second DC converter and the energy storage device if the voltage of the DC bus is greater than or equal to the voltage of the energy storage device; and conduct a power path between the DC bus and the energy storage device if the voltage of the DC bus is less than the voltage of the energy storage device.

[0025] In some embodiments, when the voltage of the DC bus is greater than the voltage of the load, the third and fourth switches are closed, and the first and second switches are opened. When the voltage of the DC bus is less than or equal to the voltage of the load, the first switch is closed, and the second, third, and fourth switches are opened.

[0026] In some embodiments, when the voltage of the DC bus is greater than or equal to the voltage of the electrical load, the first switch is closed, and the second, third, and fourth switches are opened. When the voltage of the DC bus is less than the voltage of the electrical load, the third and fourth switches are closed, and the first and second switches are opened.

[0027] In some embodiments, when the voltage of the DC bus is greater than the voltage of the energy storage device, the first switch and the second switch are closed, and the third switch and the fourth switch are opened. When the voltage of the DC bus is less than or equal to the voltage of the energy storage device, the third switch is closed, and the first switch, the second switch, and the fourth switch are opened.

[0028] In some embodiments, when the voltage of the DC bus is greater than or equal to the voltage of the energy storage device, the third switch is closed, and the first, second, and fourth switches are opened. When the voltage of the DC bus is less than the voltage of the energy storage device, the first and second switches are closed, and the third and fourth switches are opened.

[0029] In some embodiments, a fifth switch is further connected between the first output terminal of the switch subcircuit and the first DC converter, and a sixth switch is further connected between the third output terminal of the switch subcircuit and the second DC converter.

[0030] In some embodiments, the charging circuit further includes a third DC converter and a DC source. The third DC converter is connected to the DC bus and is also connected to the DC source. The switching subcircuit is further configured to conduct an electrical path between the DC source and the power load and / or energy storage device.

[0031] In some embodiments, when the DC source supplies power to the electrical load, the third switch and the fourth switch are closed. When the DC source supplies power to the energy storage device, the first switch and the second switch are closed.

[0032] In some embodiments, the charging circuit further includes an AC-DC converter connected between the DC bus and the AC bus.

[0033] In a second aspect, the present application provides a charging system, which includes the charging circuit mentioned in the first aspect and possible embodiments thereof.

[0034] In some embodiments, the charging system further includes a controller, the controller is connected to the switch subcircuit, the controller is connected to the DC bus, the controller is connected to the power load, and the controller is connected to the energy storage device.

[0035] In some embodiments, the electrical load includes a car, and the energy storage device includes a battery.

[0036] In some embodiments, the charging system includes an AC bus connected to a power grid. When the power of the power grid is less than or equal to a power threshold, the battery is powered by at least one of the power grid and the vehicle.

[0037] In some embodiments, the battery is powered by a combination of electrical grid and automobile.

[0038] In some embodiments, the charging circuit includes a switching subcircuit, a first DC converter, a second DC converter, and a DC bus. The switching subcircuit is configured to: conduct the power path between the first DC converter and the DC bus and conduct the power path between the DC bus and the second DC converter, so that the power grid supplies power to the battery through the AC-DC converter, the DC bus, and the second DC converter, while the car supplies power to the battery through the first DC converter, the DC bus, and the second DC converter.

[0039] In some embodiments, the charging circuit includes a switching subcircuit, a first DC converter, a second DC converter, and a DC bus. The switching subcircuit is configured to conduct power between the first DC converter and the battery and between the DC bus and the second DC converter, so that the grid supplies power to the battery via the AC / DC converter, the DC bus, and the second DC converter, while the vehicle supplies power to the battery via the first DC converter. The beneficial effects of the second aspect can be referenced to those of the first aspect and are not further elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0041] Figure 1 A schematic diagram of a charging circuit provided in an embodiment of the present application;

[0042] Figure 2 Another charging circuit schematic provided in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of the internal structure of a switch sub-circuit provided in an embodiment of the present application;

[0044] Figure 4 Another charging circuit schematic provided in an embodiment of the present application;

[0045] Figure 5 Another charging circuit schematic provided in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of a charging system provided in an embodiment of the present application;

[0047] Figure 7 A schematic diagram of another charging system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] In the description of the invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "back," "inner," "outer," and the like, indicating directions or positional relationships, are based on the directions or relative positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limitations on the invention. Unless otherwise specified, the above-mentioned directions may be flexibly set in actual application, provided that the relative positional relationships shown in the accompanying drawings are met.

[0050] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0051] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "communicated" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be directly connected, indirectly connected through an intermediary, or internally connected between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0052] In embodiments of the present invention, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of other identical elements in the process, article, or apparatus comprising the element.

[0053] In the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present invention should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0054] With the rapid development of the electric vehicle industry, electric vehicles are increasingly gaining market share. To speed up charging, a large number of charging piles and energy storage devices are being integrated into charging systems. For example, a large number of charging piles are integrated into charging systems consisting of AC power supply branches, photovoltaic power supply branches, and pure energy storage power supply branches.

[0055] While the coordinated power supply of energy storage devices and the grid can speed up the charging of electric vehicles, the energy storage device's energy is also decreasing as the electric vehicle is charged, so the energy storage device also needs to be charged. As more and more loads are connected to the grid, the grid load becomes heavier. The grid needs to power both electric vehicles and energy storage devices, resulting in slower energy storage device recharge and difficulty in meeting demand.

[0056] In view of this, an embodiment of the present application provides a charging circuit, illustratively, as Figure 1 As shown in FIG. The charging circuit includes a DC bus 1, a first DC converter 4, an energy storage device 5, and a second DC converter 6. The first DC converter 4 is connected between the DC bus 1 and the electrical load 2, and the second DC converter 6 is connected between the DC bus 1 and the energy storage device 5. The electrical load 2 supplies power to the energy storage device 5 at least through the first DC converter 4, and / or the DC bus 1 supplies power to the energy storage device 5 through the second DC converter 6.

[0057] In the charging circuits provided in some embodiments of the present application, the first DC converter 4 and the second DC converter 6 are both DC-DC converters configured to convert one DC voltage into another. Because the first DC converter 4 is connected between the DC bus 1 and the electrical load 2, and the second DC converter 6 is connected between the DC bus 1 and the energy storage device 5, the DC bus 1 can supply power to the electrical load 2 via the first DC converter 4, and the DC bus 1 can supply power to the energy storage device 5 via the second DC converter 6.

[0058] The electrical load 2 supplies power to the energy storage device 5 at least through the first DC converter 4, and / or the DC bus 1 supplies power to the energy storage device 5 through the second DC converter 6. This means that while the DC bus 1 supplies power to the energy storage device 5 through the second DC converter 6, the electrical load 2 can also supply power to the energy storage device 5 through the first DC converter 4. The energy storage device 5 is transformed from being only powered by the DC bus 1 to being powered by both the electrical load 2 and the DC bus 1, thus enabling high-power and fast charging. Since the electrical load 2 can supply power to the energy storage device 5, the electrical load 2 and the energy storage device 5 are transformed from being independent of each other to being interconnected, thus realizing the connection and distribution of energy between the loads (electrical load 2 and energy storage device 5).

[0059] In some embodiments, as Figure 1 As shown, the charging circuit further includes a switching subcircuit 3. The switching subcircuit 3 is connected to the DC bus 1 and is respectively connected to the electrical load 2, the first DC converter 4, the energy storage device 5, and the second DC converter 6. The switching subcircuit 3 is configured to conduct the power path between the first DC converter and the DC bus 1, and to conduct the power path between the DC bus 1 and the second DC converter 6, so that the electrical load 2 supplies power to the energy storage device 5 through the first DC converter 4, the DC bus 1, and the second DC converter 6.

[0060] The switching subcircuit 3 includes different branches. By controlling the on / off switching of these branches within the switching subcircuit 3, the voltage on the DC bus 1 can be used to supply power to the load 2 via the first DC converter 4, the voltage on the DC bus 1 can be used to supply power to the energy storage device 5 via the second DC converter 6, and the load 2 can also supply power to the energy storage device 5 while the voltage on the DC bus 1 is used to supply power to the energy storage device 5 via the second DC converter 6. As one possible power supply path, the load 2 supplies power to the energy storage device 5 via the first DC converter 4, the DC bus 1, and the second DC converter 6.

[0061] In some embodiments, as Figure 1 As shown, the switch subcircuit 3 is further configured to conduct the power path between the first DC converter 4 and the energy storage device 5, so that the electrical load 2 supplies power to the energy storage device 5 via the first DC converter 4. By eliminating the steps of transmitting power from the first DC converter 4 to the DC bus 1 and then from the DC bus 1 through the second DC converter 6, energy loss during the transmission process is reduced, resulting in faster charging of the energy storage device 5 and significantly improved efficiency.

[0062] As a possible implementation, for example, Figure 2The switch subcircuit includes a first switch 31, a second switch 32, a third switch 33, and a fourth switch 34. A first input terminal of the switch subcircuit is connected to one end of the DC bus 1, and a second input terminal of the switch subcircuit is connected to the other end of the DC bus 1.

[0063] The first output terminal 3-1 of the switch subcircuit is connected to the first DC converter 4, the second output terminal 3-2 of the switch subcircuit is connected to the energy storage device 5, the third output terminal 3-3 of the switch subcircuit is connected to the second DC converter 6, and the fourth output terminal 3-4 of the switch subcircuit is connected to the electrical load 2. A first end of the first switch 31 is connected to the first input terminal of the switch subcircuit, a second end of the first switch 31 is connected to the first output terminal 3-1 of the switch subcircuit, a first end of the second switch 32 is connected to the first output terminal 3-1 of the switch subcircuit, and a second end of the second switch 32 is connected to the second output terminal 3-2 of the switch subcircuit. A first end of the third switch 33 is connected to the second input terminal of the switch subcircuit, a second end of the third switch 33 is connected to the third output terminal 3-3 of the switch subcircuit, a first end of the fourth switch 34 is connected to the third output terminal 3-3 of the switch subcircuit, and a second end of the fourth switch 34 is connected to the fourth output terminal 3-4 of the switch subcircuit.

[0064] By controlling the first switch 31, second switch 32, third switch 33, and fourth switch 34 in the switch subcircuit, different power supply paths can be turned on and off. Specifically, when charging the energy storage device 5 and the charging power is greater than or equal to the power threshold, the switch subcircuit controls the first switch 31 and third switch 33 to close and the second switch 32 and fourth switch 34 to open. This allows the electrical load 2 to supply power to the energy storage device 5 via the first DC converter 4, the DC bus 1, and the second DC converter 6.

[0065] When the energy storage device 5 is charged and the charging power is greater than or equal to the power threshold, the switch subcircuit can also control the second switch 32 and the third switch 33 to be closed, and control the first switch 31 and the fourth switch 34 to be open.

[0066] In this case, the switching subcircuit conducts power between the DC bus 1 and the second DC converter 6 connected to the energy storage device 5, and conducts power between the utility load 2 and the first DC converter 4 and energy storage device 5. In other words, the energy storage device 5 is powered by two routes: one route originating from the DC bus 1, passing through the second DC converter 6, and then to the energy storage device 5. The other route originates from the utility load 2, undergoes voltage conversion by the first DC converter 4, and then is transmitted to the energy storage device 5. Due to the dual power supply, the charging power during the energy storage device 5 charging process is greater than or equal to the power threshold, enabling faster charging.

[0067] In some embodiments, reference Figure 2 The power supply source of the electrical load 2 includes at least one of the DC bus 1 and the energy storage device 5. The power supply source of the electrical load 2 includes at least one of the DC bus 1 and the energy storage device 5. That is, the power supply source of the electrical load 2 can be the DC bus 1, the DC bus 1 and the energy storage device 5, or the energy storage device 5.

[0068] Illustratively, the switch subcircuit is further configured to conduct an electrical path between the electrical load 2 and the second DC converter 6, so that the energy storage device 5 supplies power to the electrical load 2 via the second DC converter 6. In other embodiments, the switch subcircuit is further configured to conduct an electrical path between the first DC converter 4 and the DC bus 1, and to conduct an electrical path between the DC bus 1 and the second DC converter 6, so that the energy storage device 5 supplies power to the electrical load 2 via the second DC converter 6, the DC bus 1, and the first DC converter 4.

[0069] More specifically, when the charging power of electrical load 2 is greater than or equal to the power threshold, the power supply source for electrical load 2 includes DC bus 1 and energy storage device 5. The switching subcircuit controls the first switch 31 and the fourth switch 34 to close, and controls the second switch 32 and the third switch 33 to open.

[0070] In this case, the switching subcircuit conducts power between the DC bus 1 and the first DC converter 4 connected to the electrical load 2, and conducts power between the energy storage device 5, the second DC converter 6, and the electrical load 2. In other words, the electrical load 2 is supplied with power from two sources: one source, originating from the DC bus 1, passing through the first DC converter 4 and reaching the electrical load 2. The other source, originating from the energy storage device 5, is converted by the second DC converter 6 and then transmitted to the electrical load 2. Due to the dual power supply, the charging power during the charging process of the electrical load 2 is greater than or equal to the power threshold, enabling faster charging.

[0071] Reference Figure 1 In some embodiments, the switch subcircuit 3 is further configured to: based on the voltage of the DC bus 1 and the voltage of the electrical load 2, conduct the power path between the DC bus 1 and the first DC converter 4 and the electrical load 2, or conduct the power path between the electrical load 2 and the DC bus 1.

[0072] When the voltage of the DC bus 1 is different from the voltage of the power load 2, some branches inside the switch sub-circuit 3 will be turned on and some branches will be turned off, thereby forming two power supply paths, namely, the DC bus 1 first converts the voltage through the first DC converter 4 before supplying power to the power load 2, and the DC bus 1 directly supplies power to the power load 2.

[0073] The switching subcircuit 3 can, based on the voltage of the DC bus 1 and the voltage of the load 2, conduct the power supply path between the DC bus 1 and the first DC converter 4 and the load 2, or conduct the power supply path between the DC bus 1 and the load 2. Since the first DC converter 4 is connected to the load 2, the switching subcircuit 3 conducting the power supply path between the DC bus 1 and the first DC converter 4 and the load 2 is equivalent to the DC bus 1 supplying power to the load 2 after passing through the first DC converter 4. The switching subcircuit 3 conducting the power supply path between the DC bus 1 and the load 2 means that the DC bus 1 directly supplies power to the load 2. The charging circuit provided in this application can select the power supply path for the load 2 based on the voltage of the DC bus 1 and the voltage of the load 2, providing greater flexibility. Furthermore, the provision of two power supply paths eliminates the need to pass through the first DC converter 4 when meeting the voltage requirement of the DC bus 1 directly supplying power to the load 2, effectively improving energy conversion efficiency.

[0074] Reference Figure 1 When the electrical load 2 is charged and the charging power is less than the power threshold, the configuration of the switch sub-circuit 3 includes:

[0075] Because the voltage of the DC bus 1 is greater than the voltage of the electrical load 2 , a current path between the DC bus 1 and the electrical load 2 is opened.

[0076] Because the voltage of the DC bus 1 is less than or equal to the voltage of the electrical load 2 , the current path between the DC bus 1 and the first DC converter 4 and the electrical load 2 is turned on.

[0077] The comparison between the charging power and the power threshold mentioned in this embodiment is all under the condition that the load is already charging. Figure 1 When the voltage of DC bus 1 is greater than the voltage of load 2, switch sub-circuit 3 opens the power path between DC bus 1 and load 2, allowing DC bus 1 to directly power load 2. When the voltage of DC bus 1 is greater than the voltage of load 2, it means that the voltage of DC bus 1 is sufficient to support the power supply of load 2, so voltage conversion through first DC converter 4 is no longer required. Since the energy conversion steps are reduced, charging can be performed at a faster rate, and the partial energy loss caused by energy conversion is avoided, thereby improving the efficiency of energy transfer.

[0078] When the voltage of DC bus 1 is less than or equal to the voltage of load 2, switching sub-circuit 3 opens the power path between DC bus 1, first DC converter 4, and load 2. This allows DC bus 1 to first convert its voltage via first DC converter 4 before supplying power to load 2. When the voltage of DC bus 1 is less than or equal to the voltage of load 2, indicating a low DC bus voltage, the power path between DC bus 1 and first DC converter 4 is opened, allowing the low DC bus voltage to be boosted before supplying power to load 2, thereby increasing the charging speed of load 2.

[0079] In some embodiments, reference Figure 1 When the electrical load 2 is discharging, the switch sub-circuit 3 is further configured to: based on the voltage of the DC bus 1 being greater than or equal to the voltage of the electrical load 2, conduct the power path between the DC bus 1, the first DC converter 4, and the electrical load 2, so that the voltage of the electrical load 2 is first converted by the first DC converter 4 before being transferred to the DC bus 1. Based on the voltage of the DC bus 1 being less than the voltage of the electrical load 2, conduct the power path between the DC bus 1 and the electrical load 2, so that the electrical load 2 directly discharges the DC bus 1.

[0080] Similarly, different discharge paths are activated based on the voltage difference between load 2 and DC bus 1, allowing load 2 to discharge flexibly and efficiently into DC bus 1. This helps balance energy flow between systems. The discharge process of load 2 also helps maintain the voltage stability of DC bus 1. When load demand increases, additional current can be provided to prevent the voltage of DC bus 1 from dropping.

[0081] The above embodiments focus on the influence of the power paths in the switch subcircuit on the power load. Similarly, by controlling the on and off of different power paths within the switch subcircuit, the charging and discharging of the energy storage device can be affected.

[0082] Reference Figure 1 Exemplarily, the switch subcircuit 3 is further configured to: based on the voltage of the DC bus 1 and the voltage of the energy storage device 5, conduct the power path between the DC bus 1 and the second DC converter 6 and the energy storage device 5, or conduct the power path between the energy storage device 5 and the DC bus 1.

[0083] The switch subcircuit 3 can turn on and off some branches within the switch subcircuit 3 according to the relationship between the voltage of the DC bus 1 and the voltage of the energy storage device 5, thereby forming two power supply paths, namely, the DC bus 1 first converts the voltage through the second DC converter 6 before supplying power to the energy storage device 5, and the DC bus 1 directly supplies power to the energy storage device 5.

[0084] Furthermore, when the energy storage device 5 is being charged and the charging power is less than the power threshold, the switch subcircuit 3 is configured to: if the voltage of the DC bus 1 is greater than the voltage of the energy storage device 5, conduct the power path between the DC bus 1 and the energy storage device 5; and if the voltage of the DC bus 1 is less than or equal to the voltage of the energy storage device 5, conduct the power path between the DC bus 1 and the second DC converter 6 and the energy storage device 5.

[0085] The switch subcircuit 3 can conduct the power path between the DC bus 1 and the second DC converter 6 and the energy storage device 5, or conduct the power path between the DC bus 1 and the energy storage device 5 based on the voltage of the DC bus 1 and the voltage of the energy storage device 5. Since the second DC converter 6 is connected to the energy storage device 5, the power path conducted by the switch subcircuit 3 between the DC bus 1 and the second DC converter 6 is equivalent to the DC bus 1 supplying power to the energy storage device 5 after passing through the second DC converter 6. The power path conducted by the switch subcircuit 3 between the DC bus 1 and the energy storage device 5 means that the DC bus 1 directly supplies power to the energy storage device 5. The charging circuit provided in this application can select the power path of the energy storage device 5 according to the voltage of the DC bus 1 and the voltage of the energy storage device 5, which is more flexible. In addition, due to the setting of the two power paths, when the voltage requirement of the DC bus 1 directly supplies power to the energy storage device 5 is met, it is no longer necessary to pass through the second DC converter 6, which can effectively improve the efficiency of energy conversion.

[0086] When the voltage of the DC bus 1 is greater than the voltage of the energy storage device 5, it means that the voltage of the DC bus 1 is sufficient to support the power supply of the energy storage device 5, so there is no need to perform voltage conversion through the second DC converter 6. Since the energy conversion steps are reduced, charging can be performed at a faster rate, and the loss of part of the energy due to energy conversion is avoided, thereby improving the efficiency of energy transfer.

[0087] When the voltage of the DC bus 1 is lower than the voltage of the energy storage device 5, the power supply path between the DC bus 1 and the second DC converter 6 is opened. The DC bus 1 first undergoes voltage conversion via the second DC converter 6 before supplying power to the second load 5. When the voltage of the DC bus 1 is lower than the voltage of the second load 5, indicating that the voltage of the DC bus 1 is relatively low, the power supply path between the DC bus 1 and the second DC converter 6 is opened. This allows the lower voltage of the DC bus 1 to be boosted before supplying power to the second load 5, thereby increasing the charging speed of the second load 5.

[0088] In some embodiments, when the energy storage device 5 is discharging, the switch subcircuit 3 is configured to: conduct the power path between the DC bus 1 and the second DC converter 6 and the energy storage device 5 based on the voltage of the DC bus 1 being greater than or equal to the voltage of the energy storage device 5; and conduct the power path between the DC bus 1 and the energy storage device 5 based on the voltage of the DC bus 1 being less than the voltage of the energy storage device 5.

[0089] Similarly, different power paths are enabled based on the voltage between the energy storage device 5 and the DC bus 1, allowing the energy storage device 5 to flexibly and efficiently discharge into the DC bus 1. This helps balance energy flow between systems. The discharge process of the energy storage device 5 also helps maintain the voltage stability of the DC bus 1. When load demand increases, it can provide additional current to prevent the voltage of the DC bus 1 from dropping.

[0090] Reference Figure 2 , the following description is given for the various different situations provided in the above embodiments:

[0091] When the load is charging and the voltage of DC bus 1 is greater than that of load 2, third switch 33 and fourth switch 34 are closed, and first switch 31 and second switch 32 are open. DC bus 1 directly supplies power to load 2. When the voltage of DC bus 1 is less than or equal to that of load 2, first switch 31 is closed, and second switch 32, third switch 33, and fourth switch 34 are open. DC bus 1 is first boosted by first DC converter 4 before supplying power to load 2.

[0092] When load 2 is discharging and the voltage of DC bus 1 is greater than or equal to the voltage of load 2, first switch 31 is closed, and second switch 32, third switch 33, and fourth switch 34 are opened. Load 2 discharges directly into DC bus 1. When the voltage of DC bus 1 is less than the voltage of load 2, third switch 33 and fourth switch 34 are closed, and first switch 31 and second switch 32 are opened. Load 2 discharges into DC bus 1 after voltage conversion by first DC converter 4.

[0093] When the voltage of the DC bus 1 is greater than the voltage of the energy storage device 5, the first switch 31 and the second switch 32 are closed, and the third switch 33 and the fourth switch 34 are opened. When the voltage of the DC bus 1 is less than or equal to the voltage of the energy storage device 5, the third switch 33 is closed, and the first switch 31, the second switch 32, and the fourth switch 34 are opened.

[0094] When the voltage of the DC bus 1 is greater than or equal to the voltage of the energy storage device 5, the third switch 33 is closed, and the first switch 31, the second switch 32, and the fourth switch 34 are opened. When the voltage of the DC bus 1 is less than the voltage of the energy storage device 5, the first switch 31 and the second switch 32 are closed, and the third switch 33 and the fourth switch 34 are opened. As a possible implementation, the electrical load 2 can be a charging terminal, such as a charging station, connected to which an electric vehicle is charged, or a vehicle. The energy storage device 5 can be a rechargeable battery, an energy storage cabinet, etc.

[0095] In some embodiments, for example, Figure 3 A fifth switch 35 is further connected between the first output terminal 3 - 1 of the switch sub-circuit and the first DC converter 4 , and a sixth switch 36 is further connected between the third output terminal 3 - 3 of the switch sub-circuit and the second DC converter 6 .

[0096] When the voltage of the DC bus 1 is greater than the voltage of the electrical load 2 and also greater than the voltage of the energy storage device 5, and the electrical load 2 and the energy storage device 5 need to be charged simultaneously, the fifth switch 35 and the sixth switch 36 are disconnected, and the first switch 31, the second switch 32, the third switch 33 and the fourth switch 34 are closed. The voltage of the DC bus 1 does not need to be converted by the first DC converter 4 to supply power to the electrical load 2, nor does it need to be converted by the second DC converter 6 to supply power to the energy storage device 5. It can directly supply power to the electrical load 2 and the energy storage device 5. Therefore, while reducing energy loss and improving charging efficiency, the flexibility of the charging strategy is improved, and the electrical load 2 and the energy storage device 5 can be quickly charged at the same time.

[0097] In some embodiments, for example, Figure 4 As shown, the charging circuit also includes a third DC converter 7 and a DC source 8. The third DC converter 7 is connected to the DC bus 1 and is also connected to the DC source 8. The switching subcircuit is further configured to conduct an electrical path between the DC source 8 and the electrical load 2 and / or the energy storage device 5.

[0098] In some embodiments, for example, Figure 5 The charging circuit further includes an AC-DC converter 9, which is connected between the DC bus 1 and the AC bus 10. As a possible implementation, the AC bus 10 is connected to the power grid.

[0099] The AC bus 10 carries AC power, and the AC-DC converter 9 is used to convert the AC power into DC power. The DC power from the AC grid or the DC bus 1 is converted by the AC-DC converter 9, and the DC bus 1 carries DC power.

[0100] Further, refer to Figure 4When the DC source 8 supplies power to the electrical load 2, the third switch 33 and the fourth switch 34 are closed. When the DC source 8 supplies power to the energy storage device 5, the first switch 31 and the second switch 32 are closed.

[0101] The DC source 8 and the third DC converter 7 can serve as a backup power source in an off-grid state, that is, they can supply power to the electrical load 2 and / or the energy storage device 5 when the voltage on the DC bus 1 is 0. For example, in an off-grid state, the electrical load 2 needs to be charged, the fourth switch 34 and the fifth switch 35 in the switch subcircuit are closed, the sixth switch 36 is disconnected, and the DC source 8 converts the voltage through the third DC converter 7 to supply power to the electrical load 2. Similarly, in an off-grid state, the energy storage device 5 needs to be charged, the first switch 31 and the second switch 32 in the switch subcircuit are closed, the third switch 33 is disconnected, and the DC source 8 converts the voltage through the third DC converter 7 to supply power to the energy storage device 5. Since only one energy conversion step is performed, that is, only voltage conversion is performed through the third DC converter 7, the energy loss is low, thereby ensuring the efficiency of charging.

[0102] For another example, the DC source 8 may intervene when the power supply of the grid is insufficient, that is, when the voltage on the DC bus 1 after conversion by the AC-DC converter 9 is insufficient, the DC source 8 and the DC bus 1 together supply power to the electrical load 2.

[0103] The DC source 8 can also serve as a main power source. For example, the DC source 8 supplies power to the electrical load 2 independently. When the DC source 8 alone cannot support the power supply to the electrical load 2, the grid power supply intervenes.

[0104] As a possible implementation, the first AC-DC converter 4 , the second DC converter 6 , and the third DC converter 7 are all identical, all different, or partially identical.

[0105] The present application provides a charging system, which includes the charging circuit as described above.

[0106] For example, Figure 6 The charging system includes: the charging circuit 100 and the controller 11 as mentioned in the above embodiment. The controller 11 is connected to the switch sub-circuit 3, the controller 11 is connected to the DC bus 1, the controller 11 is connected to the power load 2, and the controller 11 is connected to the energy storage device 5.

[0107] The controller 11 is used to obtain the voltage of the DC bus 1, the voltage of the power load 2, the voltage of the energy storage device 5, and receive control instructions, which instruct the charging or discharging of the load.

[0108] Controller 11 controls the on / off switching of each switch in switch subcircuit 3 by obtaining the voltage of electrical load 2, the voltage of energy storage device 5, and the charge or discharge control instructions. This allows electrical load 2 and energy storage device 5 to be matched to a more appropriate charging or discharging path, improving energy conversion efficiency and accelerating charging speed. In one possible implementation, electrical load 2 includes a car, and energy storage device 5 includes a battery.

[0109] In some embodiments, the charging system includes an AC bus 10 connected to a power grid 20. When the power of the power grid 20 is less than or equal to a power threshold, the battery (energy storage device 5) is powered by at least one of the power grid 20 and the vehicle (electrical load). If the power of the power grid 20 is insufficient, the vehicle and the power grid 20 work together to power the battery. Compared to powering the battery solely from the power grid 20, using an idle vehicle and the power grid 20 to power the battery increases the power supply, thereby enabling faster battery charging.

[0110] The energy of idle cars is distributed to batteries that need to be charged urgently, which means that the electrical loads and energy storage devices are transformed from being independent of each other to being interconnected, realizing the connection and distribution of energy between loads (electrical loads and energy storage devices) and improving energy utilization.

[0111] As a large number of charging stations and energy storage devices are incorporated into the charging system, the current load that the charging system needs to handle will also increase accordingly, and the requirements for the reliability and energy transmission efficiency of the charging system will also become higher. Especially when the grid load is high, it is necessary to ensure a balance between different power supply branches (such as AC power supply, photovoltaic power supply, and pure energy storage power supply) to improve the stability and efficiency of the system. However, existing charging systems often require multiple stages of AC-DC converters, DC converters, and AC converters in the charging path from the grid to the load, resulting in low energy conversion efficiency.

[0112] In the embodiment of the present application, since the opening and closing of the multiple switches within the switch subcircuit 3 can realize the conduction or closing of the power path between the power load 2, the energy storage device 5, the first DC converter 4, and the second DC converter 6, the first DC converter 4 converts the voltage of the DC bus 1 to supply it to the power load 2, and is also reused to convert the voltage of the power load 2 to supply it to the energy storage device 5. Similarly, the second DC converter 6 converts the voltage of the DC bus 1 to supply it to the energy storage device 5, and is also reused to convert the voltage of the energy storage device 5 to supply it to the power load 2. In the process in which the power load 2 and the DC bus 1 (i.e., the power grid) jointly supply power to the energy storage device 5, or in the process in which the energy storage device 5 and the DC bus 1 jointly supply power to the power load, the power supply power of the energy storage device 5 and the power load 2 is the sum of the power output by the first DC converter 4 and the second DC converter 6.

[0113] For example, the output power of the first DC converter 4 and the second DC converter 6 is both 100 kW. In the process of the electrical load 2 and the DC bus 1 (that is, the power grid) jointly supplying power to the energy storage device 5, the power supply power received by the energy storage device 5 is 200 kW. In the process of the energy storage device 5 and the DC bus 1 jointly supplying power to the electrical load, the power supply power received by the electrical load 2 is 200 kW. When a traditional power supply system wants to achieve the same power supply power, it is necessary to connect two DC converters with an output power of 100 kW in series between the electrical load 2 and the DC bus 1, and two DC converters with an output power of 100 kW in series between the energy storage device 5 and the DC bus 1. However, the present application reduces the number of required DC converters by adding a switching sub-circuit 3. The reduction in the number of DC converters means that the loss during energy transmission is reduced, and the energy transmission efficiency is improved.

[0114] In some embodiments, for example, Figure 7 The battery 5 is powered by a power grid 20 and a car 2 .

[0115] In some embodiments, the charging circuit includes a switching subcircuit 3, a first DC converter 4, a second DC converter 6, and a DC bus 1. The switching subcircuit 3 is configured to: conduct the power path between the first DC converter 4 and the DC bus 1 and conduct the power path between the DC bus 1 and the second DC converter 6, so that the power grid supplies power to the battery 5 through the AC-DC converter 9, the DC bus 1, and the second DC converter 6, while the car supplies power to the battery 5 through the first DC converter 4, the DC bus 1, and the second DC converter 6.

[0116] In some embodiments, the charging circuit includes a switching subcircuit 3, a first DC converter 4, a second DC converter 6, and a DC bus 1. The switching subcircuit 3 is configured to: conduct the power path between the first DC converter 4 and the battery 5 and conduct the power path between the DC bus 1 and the second DC converter 6, so that the power grid 20 supplies power to the battery 5 through the AC-DC converter 9, the DC bus 1, and the second DC converter 6, while the car supplies power to the battery through the first DC converter 4.

[0117] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0118] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A charging circuit, characterized in that: It includes a DC bus, an energy storage device, a first DC converter and a second DC converter; The first DC converter is connected between the DC bus and the power load. The second DC converter is connected between the DC bus and the energy storage device. The electrical load supplies power to the energy storage device at least through the first DC converter, and / or the DC bus supplies power to the energy storage device through the second DC converter.

2. The charging circuit according to claim 1, wherein: The charging circuit further includes a switch subcircuit, the switch subcircuit is connected to the DC bus, and the switch subcircuit is respectively connected to the first DC converter, the power load, the second DC converter, and the energy storage device; The switching subcircuit is configured to: conduct the power path between the first DC converter and the DC bus and conduct the power path between the DC bus and the second DC converter, so that the power load supplies power to the energy storage device through the first DC converter, the DC bus, and the second DC converter.

3. The charging circuit according to claim 2, wherein: The switch subcircuit is further configured to: conduct a power path between the first DC converter and the energy storage device, so that the power load supplies power to the energy storage device through the first DC converter.

4. The charging circuit according to claim 2 or 3, characterized in that: The switch subcircuit includes a first input terminal, a second input terminal, a first output terminal, a second output terminal, a third output terminal and a fourth output terminal; The first input terminal and the second input terminal of the switch sub-circuit are respectively connected to the DC bus; The first output end of the switch subcircuit is connected to the first DC converter, the second output end of the switch subcircuit is connected to the energy storage device, the third output end of the switch subcircuit is connected to the second DC converter, and the fourth output end of the switch subcircuit is connected to the power load.

5. The charging circuit according to claim 4, characterized in that: The switch subcircuit includes a first switch, a second switch, a third switch and a fourth switch; a first end of the first switch connected to the first input end of the switch subcircuit, a second end of the first switch connected to the first output end of the switch subcircuit, a first end of the second switch connected to the first output end of the switch subcircuit, and a second end of the second switch connected to the second output end of the switch subcircuit; The first end of the third switch is connected to the second input end of the switch sub-circuit, the second end of the third switch is connected to the third output end of the switch sub-circuit, the first end of the fourth switch is connected to the third output end of the switch sub-circuit, and the second end of the fourth switch is connected to the fourth output end of the switch sub-circuit.

6. The charging circuit according to claim 5, characterized in that: When the energy storage device is charged and the charging power is greater than or equal to a power threshold, the switch subcircuit controls the first switch and the third switch to be closed, and controls the second switch and the fourth switch to be open.

7. The charging circuit according to claim 5, characterized in that: When the energy storage device is charged and the charging power is greater than or equal to a power threshold, the switch subcircuit controls the second switch and the third switch to be closed, and controls the first switch and the fourth switch to be open.

8. The charging circuit according to claim 5, wherein: The power supply source of the electrical load includes at least one of the DC bus and the energy storage device.

9. The charging circuit according to claim 8, characterized in that: The switch subcircuit is further configured to: conduct a power path between the electrical load and the second DC converter, so that the energy storage device supplies power to the electrical load through the second DC converter.

10. The charging circuit according to claim 8, wherein: The switching subcircuit is further configured to: conduct an electrical path between the first DC converter and the DC bus and conduct an electrical path between the DC bus and the second DC converter, so that the energy storage device supplies power to the electrical load through the second DC converter, the DC bus, and the first DC converter.

11. The charging circuit according to claim 8, wherein: When the charging power of the electrical load is greater than or equal to the power threshold, the power supply source of the electrical load includes the DC bus and the energy storage device; The switch subcircuit controls the first switch and the fourth switch to be closed, and controls the second switch and the third switch to be open.

12. The charging circuit according to claim 5, characterized in that: The switch subcircuit is further configured to: Based on the voltage of the DC bus and the voltage of the electrical load, a power path is conducted between the DC bus and the first DC converter and the electrical load, or a power path is conducted between the electrical load and the DC bus.

13. The charging circuit according to claim 12, wherein: When the electrical load is charged and the charging power is less than the power threshold, the switch subcircuit is configured to: Based on the voltage of the DC bus being greater than the voltage of the electrical load, conducting an electrical path between the DC bus and the electrical load; Based on the voltage of the DC bus being less than or equal to the voltage of the electrical load, a power path between the DC bus, the first DC converter, and the electrical load is conducted.

14. The charging circuit according to claim 12, wherein: When the electrical load is discharged, the switching subcircuit is further configured to: Based on the voltage of the DC bus being greater than or equal to the voltage of the electrical load, conducting a power path between the DC bus, the first DC converter, and the electrical load; Based on the voltage of the DC bus being lower than the voltage of the electrical load, a power path between the DC bus and the electrical load is conducted.

15. The charging circuit according to claim 5, characterized in that: The switch subcircuit is further configured to: Based on the voltage of the DC bus and the voltage of the energy storage device, a power path is conducted between the DC bus and the second DC converter and the energy storage device, or a power path is conducted between the energy storage device and the DC bus.

16. The charging circuit according to claim 15, characterized in that: When the energy storage device is charged and the charging power is less than the power threshold, the switch subcircuit is configured to: Based on the voltage of the DC bus being greater than the voltage of the energy storage device, conducting a power path between the DC bus and the energy storage device; Based on the voltage of the DC bus being less than or equal to the voltage of the energy storage device, a power path between the DC bus, the second DC converter, and the energy storage device is conducted.

17. The charging circuit according to claim 15, wherein: When the energy storage device is discharged, the switch subcircuit is configured to: Based on the voltage of the DC bus being greater than or equal to the voltage of the energy storage device, conducting a power path between the DC bus and the second DC converter and the energy storage device; Based on the voltage of the DC bus being lower than the voltage of the energy storage device, a power path between the DC bus and the energy storage device is conducted.

18. The charging circuit according to claim 13, wherein: When the voltage of the DC bus is greater than the voltage of the power load, the third switch and the fourth switch are closed, and the first switch and the second switch are opened; When the voltage of the DC bus is less than or equal to the voltage of the electrical load, the first switch is closed, and the second switch, the third switch, and the fourth switch are opened.

19. The charging circuit according to claim 14, wherein: When the voltage of the DC bus is greater than or equal to the voltage of the power load, the first switch is closed, and the second switch, the third switch, and the fourth switch are opened; When the voltage of the DC bus is lower than the voltage of the electrical load, the third switch and the fourth switch are closed, and the first switch and the second switch are opened.

20. The charging circuit according to claim 16, wherein: When the voltage of the DC bus is greater than the voltage of the energy storage device, the first switch and the second switch are closed, and the third switch and the fourth switch are opened; When the voltage of the DC bus is less than or equal to the voltage of the energy storage device, the third switch is closed, and the first switch, the second switch, and the fourth switch are opened.

21. The charging circuit according to claim 17, wherein: When the voltage of the DC bus is greater than or equal to the voltage of the energy storage device, the third switch is closed, and the first switch, the second switch and the fourth switch are opened; When the voltage of the DC bus is lower than the voltage of the energy storage device, the first switch and the second switch are closed, and the third switch and the fourth switch are opened.

22. The charging circuit according to claim 5, characterized in that A fifth switch is further connected between the first output end of the switch subcircuit and the first DC converter, and a sixth switch is further connected between the third output end of the switch subcircuit and the second DC converter.

23. The charging circuit according to claim 5, characterized in that: The charging circuit further includes a third DC converter and a DC source; The third DC converter is connected to the DC bus, and the third DC converter is also connected to the DC source; The switch subcircuit is further configured to conduct an electrical path between the DC source and the electrical load and / or energy storage device.

24. The charging circuit according to claim 23, wherein: When the DC source supplies power to the electrical load, the third switch and the fourth switch are closed; when the DC source supplies power to the energy storage device, the first switch and the second switch are closed.

25. The charging circuit according to claim 5, characterized in that The charging circuit further includes an AC-DC converter connected between the DC bus and the AC bus.

26. A charging system, characterized in that: The charging circuit comprises the charging circuit according to any one of claims 1 to 25.

27. The charging system according to claim 26, characterized in that The charging system further includes a controller, wherein the controller is connected to the switch subcircuit, the controller is connected to the DC bus, the controller is connected to the power load, and the controller is connected to the energy storage device.

28. The charging system according to claim 26, wherein: The electrical load includes a car, and the energy storage device includes a battery.

29. The charging system according to claim 28, characterized in that The charging system further includes an AC busbar connected to the power grid; When the power of the grid is less than or equal to a power threshold, the power supply source of the battery includes at least one of the grid and the car.

30. The charging system according to claim 28, wherein: The battery's power supply sources include the power grid and the vehicle.

31. The charging system according to claim 30, wherein: The charging circuit includes a switching subcircuit, a first DC converter, a second DC converter, and a DC bus. The switching subcircuit is configured to conduct a power path between the first DC converter and the DC bus, and to conduct a power path between the DC bus and the second DC converter, so that the power grid supplies power to the battery through the AC-DC converter, the DC bus, and the second DC converter, while the vehicle supplies power to the battery through the first DC converter, the DC bus, and the second DC converter.

32. The charging system according to claim 30, wherein: The charging circuit includes a switching subcircuit, a first DC converter, a second DC converter, and a DC bus. The switching subcircuit is configured to conduct a power path between the first DC converter and the battery and between the DC bus and the second DC converter, so that the power grid supplies power to the battery through the AC-DC converter, the DC bus, and the second DC converter, while the vehicle supplies power to the battery through the first DC converter.

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