A charging circuit and charging pile

Abstract

The utility model provides a kind of charging circuit and charging pile, charging circuit includes: direct current battery, AC / DC conversion unit, charging path, energy input unit;Wherein, the AC / DC conversion unit is connected between power grid and the direct current battery, and the energy input unit connects the direct current battery;The direct current battery and the energy input unit connect the charging path;Insulation component is provided on the path that the energy input unit is connected with the direct current battery.The charging circuit of the utility model can realize storage, light storage, light storage and charging integration, and insulation component is set to ensure that charging circuit can operate safely.

Description

Technical Field

[0001] This utility model relates to the technical field of charging systems, and in particular to a charging circuit and a charging pile. Background Technology

[0002] Under the global consensus on carbon neutrality, the photovoltaic-storage-charging system integrates photovoltaic power generation and electric vehicle charging, replacing fossil fuels and reducing carbon emissions, becoming a key path for optimizing the energy structure. The intermittent defects of photovoltaic power generation are buffered by energy storage systems, achieving efficient absorption of renewable energy and forming a closed-loop ecosystem of "vehicle-charging station-electricity".

[0003] The photovoltaic-storage-charging system integrates three different types of equipment: photovoltaic converters, energy storage converters, and charging equipment. These three types of equipment have different functional characteristics, and each type has its own independent electrical safety standards. Currently, most applications are based on the independent use of a single type of equipment. There are already mixed demonstration applications of power electronic equipment with different integration types, such as energy storage-charging, photovoltaic-storage, and photovoltaic-storage-charging. To ensure safe operation, achieving compatibility and safe operation between different types of equipment is crucial. Utility Model Content

[0004] This utility model mainly provides a charging circuit and a charging pile, which can realize the integration of energy storage and charging, photovoltaic energy storage, and photovoltaic energy storage and charging.

[0005] To solve the above-mentioned technical problems, the first technical solution adopted by this utility model is: to provide a charging circuit, including: a DC battery, an AC / DC conversion unit, a charging path, and an energy input unit;

[0006] The AC / DC conversion unit is connected between the power grid and the DC battery, and the energy input unit is connected to the DC battery.

[0007] The DC battery and the energy input unit are connected to the charging path;

[0008] An insulating component is provided on the path connecting the energy input unit to the DC battery.

[0009] In one embodiment, the energy input unit includes a photovoltaic input source and a battery input source;

[0010] Insulating components are provided on the pathways connecting the photovoltaic input source and the battery input source to the DC battery;

[0011] The photovoltaic input source and the battery input source are respectively connected to the charging path.

[0012] In one embodiment, the insulating assembly includes: a first switching assembly and a second switching assembly;

[0013] In the path connecting the photovoltaic input source and the DC battery, the first end of the first switch assembly is connected to the DC battery, the second end of the first switch assembly is connected to the first end of the second switch assembly, and the second end of the second switch assembly is connected to the photovoltaic input source.

[0014] In the path connecting the battery input source and the DC battery, the first end of the first switch assembly is connected to the DC battery, the second end of the first switch assembly is connected to the first end of the second switch assembly, and the second end of the second switch assembly is connected to the battery input source.

[0015] In one embodiment, the photovoltaic input source, the battery input source, and the DC battery are connected to a DC bus, and the charging path is connected through the DC bus.

[0016] In one embodiment, the charging path includes: a first charging path, a second charging path, and a first switching unit connecting the first charging path and the second charging path;

[0017] The DC battery is connected to the first charging path and the second charging path, the photovoltaic input source is connected to the first charging path, and the battery input source is connected to the second charging path.

[0018] In one embodiment, the first charging path includes: a first conversion unit, a second switching unit, and a first charging gun connected in series; the second charging path includes: a second conversion unit, a third switching unit, and a second charging gun connected in series.

[0019] Wherein, the first end of the first switching unit is connected to the first node between the first conversion unit and the second switching unit, the second end of the first switching unit is connected to the second node between the second conversion unit and the third switching unit; and the photovoltaic input source is connected to the first conversion unit, and the battery input source is connected to the second conversion unit.

[0020] In one embodiment, the AC / DC conversion unit includes: a first disconnect switch and a current conversion module, wherein the first disconnect switch is connected between the AC terminal of the AC / DC conversion unit and the current conversion module.

[0021] In one embodiment, the path connecting the AC / DC conversion unit to the power grid further includes:

[0022] A second disconnecting switch is connected between the power grid and the AC terminal of the AC / DC conversion unit; and / or

[0023] The third isolating switch is connected between the second isolating switch and the AC terminal of the AC / DC conversion unit.

[0024] In one embodiment, the DC port and AC port of the charging circuit further include an insulating capacitor.

[0025] In one embodiment, the charging circuit further includes a control unit connected between the AC terminal of the AC / DC conversion unit and the DC terminal of the AC / DC conversion unit.

[0026] The control unit includes a control circuit, a first transformer, and a second transformer. The control circuit is connected to the AC terminal of the AC / DC conversion unit through the first transformer, and the control circuit is connected to the DC terminal of the AC / DC conversion unit through the second transformer.

[0027] To solve the above-mentioned technical problems, the second technical solution adopted by this utility model is to provide a charging pile, including the charging circuit described in any of the above-mentioned items.

[0028] The beneficial effects of this utility model are as follows: Unlike existing technologies, the charging circuit provided by this utility model includes: a DC battery, an AC / DC conversion unit, a charging path, and an energy input unit; wherein, the AC / DC conversion unit is connected between the power grid and the DC battery, and the energy input unit is connected to the DC battery; the DC battery and the energy input unit are connected to the charging path; an insulating component is provided on the path connecting the energy input unit and the DC battery. The charging circuit of this utility model can achieve integrated energy storage and charging, photovoltaic energy storage, and photovoltaic energy storage and charging, and the insulating component ensures the safe operation of the charging circuit. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the first embodiment of the charging circuit of this utility model;

[0031] Figure 2 This is a schematic diagram of the second embodiment of the charging circuit of this utility model;

[0032] Figure 3 This is a schematic diagram of the third embodiment of the charging circuit of this utility model;

[0033] Figure 4 This is a schematic diagram of the fourth embodiment of the charging circuit of this utility model;

[0034] Figure 5 This is a schematic diagram of the structure of a charging pile according to an embodiment of the present invention. Detailed Implementation

[0035] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0036] In the following description, specific details such as particular system structures, interfaces, and technologies are set forth for illustrative purposes rather than for limiting purposes, in order to provide a thorough understanding of the present invention.

[0037] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, "more" in this article means two or more objects.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to limit the invention.

[0039] Before providing a further detailed description of the embodiments of this utility model, the nouns and terms involved in the embodiments of this utility model will be explained, and the nouns and terms involved in the embodiments of this utility model are subject to the following interpretations.

[0040] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] See Figure 1 , Figure 1 This is a schematic diagram of the structure of an embodiment of the charging circuit of this utility model, specifically including: a DC battery 12, an AC / DC conversion unit 11, a charging path 13, and an energy input unit 15.

[0042] The AC / DC conversion unit 11 is connected between the power grid and the DC battery 12 to convert the AC power supplied by the power grid into DC power to charge the DC battery 12. The AC / DC conversion unit 11 is an AC / DC converter, which requires insulation design. For example, the AC / DC conversion unit 11 can be set to basic insulation or reinforced insulation.

[0043] It should be noted that basic insulation has a relatively simple structure, typically consisting of a single layer of insulating material directly wrapping the live parts. It provides only basic protection against electric shock. When basic insulation fails, the equipment may lose its protective capability, posing a risk of electric shock. Reinforced insulation, on the other hand, has a higher insulation strength than basic insulation and a more complex structure. It employs multiple layers of different types of insulating materials, or undergoes special treatment to increase insulation thickness and strength. Even if basic insulation fails, reinforced insulation can still effectively prevent electric shock, providing more reliable protection and significantly reducing the likelihood of electric shock.

[0044] Depending on the actual application scenario, the AC / DC converter can be designed with basic insulation or enhanced insulation. In a preferred embodiment, the AC / DC converter is configured with enhanced insulation. Specifically, the enhanced insulation design needs to meet predetermined electrical clearance requirements, impulse voltage requirements, and the maximum voltage creepage distance design corresponding to the system to ensure the safe operation of the equipment.

[0045] The energy input unit 15 is connected to the DC battery 12 and is used to charge the DC battery 12. The DC battery 12 and the energy input unit 15 are connected to the charging path 13, through which the load is charged.

[0046] In one embodiment, an insulating component 14 is provided on the path connecting the energy input unit 15 and the DC battery 12. The insulating component 14 can achieve insulation between the energy input unit 15 and the DC battery 12, ensuring the safe operation of the charging circuit.

[0047] In the embodiments of this application, combined with Figure 2 The energy input unit 15 includes a photovoltaic input source and / or a battery input source. The photovoltaic input source converts solar energy into direct current (DC) to charge the DC battery 12 via a solar photovoltaic module (PV module). The battery input source can convert stored chemical energy into DC to charge the DC battery 12.

[0048] This utility model is illustrated using the energy input unit 15, which includes a photovoltaic input source 151 and a battery input source 152, as an example. Specifically, it is combined with... Figure 2 The charging circuit of this utility model integrates energy storage and charging (implemented by DC battery 12 and battery input source 152), photovoltaic energy storage (implemented by photovoltaic input source 151 and DC battery 12), and photovoltaic energy storage and charging (implemented by DC battery 12, photovoltaic input source 151 and battery input source 152) into one design.

[0049] Furthermore, the photovoltaic input source 151 and the battery input source 152 are respectively connected to the charging path 13, which is used to connect to the load. Therefore, the photovoltaic input source 151 and the battery input source 152 can be connected to the load through the charging path 13 to charge the load.

[0050] Photovoltaic input source 151 and battery input source 152 are respectively connected to DC battery 12, and an insulating component 14 is provided on the path connecting the photovoltaic input source 151 and the battery input source 152 to the DC battery 12. Specifically, when the photovoltaic input source 151 and the battery input source 152 are charging the DC battery 12, the insulating component 14 is in a non-insulating state, and the photovoltaic input source 151 and the battery input source 152 charge the DC battery 12 through the insulating component 14. However, when the photovoltaic input source 151 and the battery input source 152 are charging the load through the charging path 13, the insulating component 14 is in an insulating state.

[0051] In one embodiment, the AC / DC conversion unit 11 of this invention can be a bidirectional current-carrying device, capable of supporting both AC current from the grid to the DC battery 12 and DC current from the DC battery 12 to the grid. In this embodiment, the AC / DC converter is a non-isolated AC / DC converter, and the DC battery 12, photovoltaic input source 151, and battery input source 152 are connected to the grid through the non-isolated AC / DC converter. Specifically, the insulating component 14 is in a non-isolated state, connecting the photovoltaic input source 151 and battery input source 152 to the DC battery 12, which in turn connects to the grid. At this time, the DC battery 12, photovoltaic input source 151, and battery input source 152 are connected to the grid through the bidirectional AC / DC converter, achieving grid connection, allowing it to both obtain and supply electrical energy to the grid.

[0052] In one specific embodiment, combined with Figure 3 The insulating component 14 includes a first switching component M1 and a second switching component M2. The first switching component M1 and the second switching component M2 are connected in series. Specifically, in the path connecting the photovoltaic input source 151 and the DC battery 12, the first end of the first switching component M1 is connected to the DC battery 12, the second end of the first switching component M1 is connected to the first end of the second switching component M2, and the second end of the second switching component M2 is connected to the photovoltaic input source 151. In the path connecting the battery input source 152 and the DC battery 12, the first end of the first switching component M1 is connected to the DC battery 12, the second end of the first switching component M1 is connected to the first end of the second switching component M2, and the second end of the second switching component M2 is connected to the battery input source 152.

[0053] Specifically, in an insulating assembly 14, the switching on and off of the first switching assembly M1 and the second switching assembly M2 are independently controlled. Furthermore, Figure 3All switching components in the two insulating assemblies 14 shown can be controlled independently, and there are no specific limitations. It should be noted that setting the switches to independent control ensures safety under a single fault. Specifically, in a charging system, if a component or circuit fails (such as a short circuit or leakage), the fault may spread to the entire system if the switching components are not individually controlled, leading to serious consequences. By setting the switching components to be individually controlled, when a part fails, the faulty circuit can be disconnected by controlling the corresponding switching component, preventing the fault from affecting other parts. In this embodiment, the first switching component M1 and the second switching component M2 achieve enhanced insulation between the photovoltaic input source 151, the DC battery 12, the battery input source 152, and the charging gun. By disconnecting a portion of the switching components, the circuits between the photovoltaic input source 151, the DC battery 12, the battery input source 152, and the charging gun can be physically separated. Simultaneously, individually controlling these switching components ensures sufficient insulation resistance between each part under different operating states as needed. For example, before or after charging, the relevant switching components can be disconnected to electrically isolate the photovoltaic input source 151, DC battery 12, battery input source 152 and charging gun, greatly improving insulation. During charging, the state of the switching components can also be reasonably controlled, and in conjunction with the insulation detection circuit, the insulation between each part can be monitored in real time to ensure that it meets the requirements, thereby achieving the purpose of strengthening insulation.

[0054] The first switch assembly M1 and the second switch assembly M2 are, for example, relay switches.

[0055] In one embodiment of this invention, the photovoltaic input source 151, the battery input source 152, and the DC battery 12 can also be directly connected to a DC bus, and the charging path 13 is connected through the DC bus to charge the load. In this embodiment, the insulating components 14 on the path between the photovoltaic input source 151, the battery input source 152, and the DC battery 12 can be removed. Alternatively, the insulating components 14 on the path between the photovoltaic input source 151, the battery input source 152, and the DC battery 12 can be replaced by only the first switch component M1, reducing costs.

[0056] When the AC / DC conversion unit 11, photovoltaic input source 151, and battery input source 152 jointly charge a load, such as an electric vehicle, through the charging path 13, the AC power supplied by the grid mainly flows through the AC / DC conversion unit 11 to supply the DC battery 12, and then the DC battery 12 charges the load. In this case, the AC / DC conversion unit 11, i.e., the AC / DC converter, is configured with reinforced insulation. However, the photovoltaic input source 151 and battery input source 152 can directly charge the load through the charging path 13, in which case the charging path 13 can be configured with reinforced insulation. In one embodiment, the charging path 13 is equipped with a DC / DC converter; configuring the DC / DC converter with reinforced insulation satisfies the reinforced insulation requirements of the charging path 13.

[0057] Furthermore, when the photovoltaic input source 151 and the DC battery 12 are in the charging phase, the insulating component 14 is in an insulating state, thereby protecting the photovoltaic input source 151 and the DC battery 12. In one embodiment, the switching component in the insulating component 14 is a relay switch, which is in an insulating state when it is in the open state and in a non-insulating state when it is in the on state.

[0058] Further integration Figure 3 The charging path 13 includes a first charging path 131 and a second charging path 132. Each of the first charging path 131 and the second charging path 132 has a charging gun for charging the load. To achieve electrical insulation between the first charging path 131 and the second charging path 132, a first switching unit T1 is provided between them. Specifically, the first switching unit T1 connects the first charging path 131 and the second charging path 132. A DC battery 12 is connected to both the first charging path 131 and the second charging path 132. The photovoltaic input source 151 is connected to the first charging path 131, and the battery input source 152 is connected to the second charging path 132.

[0059] Specifically, when charging gun A in the first charging path 131 establishes a connection with the load to charge the load, the first switch unit T1 closes. At this time, the DC battery 12 and the photovoltaic input source 151 charge the load through the first charging path 131, and the battery input source 152 charges the load through the second charging path 132, the first switch unit T1, and the first charging path 131. When charging gun B in the second charging path 132 establishes a connection with the load to charge the load, the first switch unit T1 closes. At this time, the DC battery 12 and the battery input source 152 charge the load through the second charging path 132, and the photovoltaic input source 151 charges the load through the first charging path 131, the first switch unit T1, and the second charging path 132. Furthermore, when both the charging gun A in the first charging path 131 and the charging gun B in the second charging path 132 are connected to the load to charge the load, the first switching unit T1 is disconnected. At this time, the DC battery 12 and the photovoltaic input source 151 charge the load through the first charging path 131, and the DC battery 12 and the battery input source 152 charge the load through the second charging path 132.

[0060] In one embodiment, the first charging path 131 includes a first conversion unit 1311, a second switching unit T2, and a first charging gun (i.e., charging gun A) connected in series. The second charging path 132 includes a second conversion unit 1321, a third switching unit T3, and a second charging gun (i.e., charging gun B) connected in series. The first end of the first switching unit T1 is connected to a first node n1 between the first conversion unit 1311 and the second switching unit T2, and the second end of the first switching unit T1 is connected to a second node n2 between the second conversion unit 1321 and the third switching unit T3. In this embodiment, a photovoltaic input source 151 is connected to the first conversion unit 1311, and a battery input source 152 is connected to the second conversion unit 1321.

[0061] It should be noted that the first conversion unit 1311 and the second conversion unit 1321 are DC / DC converters. When charging gun A establishes a connection with the load to charge it, the second switch unit T2 closes; after charging is complete, the second switch unit T2 opens. When charging gun B establishes a connection with the load to charge it, the third switch unit T3 closes; after charging is complete, the third switch unit T3 opens. This provides safety protection for the operator. The DC / DC converter is designed with reinforced insulation.

[0062] In one embodiment, combined with Figure 4The AC / DC conversion unit 11 includes a first disconnect switch 111 and a current conversion module 112. The first disconnect switch 111 is connected between the AC terminal of the AC / DC conversion unit 11 and the current conversion module 112. In grid-connected mode, the photovoltaic input source 151, the battery input source 152, and the DC battery 12 may also be connected to important loads. If the DC battery 12 cannot be disconnected, the first disconnect switch 111 can be controlled to open in order to maintain the AC path between the power grid and the AC / DC conversion unit 11.

[0063] In one embodiment, in grid-connected mode, if the AC / DC conversion unit 11 is a non-isolated AC / DC converter, the first isolation switch 111 includes switch K3 and switch K4, and switches K3 and K4 are controlled independently to achieve electrical isolation between the AC path and the DC battery 12, while ensuring safety under a single fault. In another embodiment, if the AC / DC conversion unit 11 is an isolated AC / DC converter, the first isolation switch 111 includes switch K3 or switch K4 to achieve electrical isolation between the AC path and the DC battery 12.

[0064] Specifically, to improve efficiency and power density, the AC / DC conversion unit 11 can be designed as a non-isolated AC / DC converter. Since the non-isolated AC / DC converter is no longer directly connected to the charging operator, isolation between the AC path and the DC battery 12 or DC bus is achieved through disconnect switches K3 and K4 in the AC / DC conversion unit 11. Therefore, in bidirectional applications, since the DC bus and DC battery 12 are energized, series switches K3 and K4 need to be added to the AC / DC conversion unit 11 to address the potential hazards caused by a single fault. Secondly, for the bidirectional AC / DC conversion unit 11, to monitor the entire circuit in real time, power is simultaneously drawn from both the AC and DC sides to provide power to the control circuit, enabling monitoring of the entire system status.

[0065] It should be noted that isolated AC / DC converters achieve electrical isolation between the mains input and DC output through components such as transformers and optocouplers; there is no direct conductive connection between the two. Non-isolated AC / DC converters, on the other hand, have a direct electrical connection (such as a common ground) between the mains input and DC output, and lack isolation components.

[0066] In one embodiment, the path connecting the AC / DC conversion unit 11 to the power grid further includes a second disconnecting switch K1 and / or a third disconnecting switch K2. This invention will be described using the example of the AC / DC conversion unit 11 connecting to the power grid including a second disconnecting switch K1 and a third disconnecting switch K2.

[0067] The second disconnecting switch K1 is connected between the power grid and the AC terminal of the AC / DC conversion unit 11; the third disconnecting switch K2 is connected between the second disconnecting switch K1 and the AC terminal of the AC / DC conversion unit 11.

[0068] During normal operation, or when maintaining the connection between the third disconnector switch K2 and the AC / DC conversion unit 11, or during maintenance of the AC / DC conversion unit 11, the second disconnector switch K1 can be manually disconnected to ensure the safety of maintenance personnel. In case of abnormalities or emergency stop, the third disconnector switch K2 can be controlled to open, thereby disconnecting the power grid from the AC / DC conversion unit 11 and protecting the circuit safety.

[0069] The charging circuit of this invention also includes a control unit 16, which is connected between the AC terminal and the DC terminal of the AC / DC conversion unit 11. Specifically, the control unit 16 includes a control circuit 163, a first transformer 161, and a second transformer 162. The control circuit 163 is connected to the AC terminal of the AC / DC conversion unit 11 through the first transformer 161, and the control circuit 163 is connected to the DC terminal of the AC / DC conversion unit 11 through the second transformer 162.

[0070] Based on safety principles, this invention requires two independent transformers to draw power from the DC and AC terminals of the AC / DC conversion unit 11 for monitoring. Using two independent transformers to draw power from the AC and DC sides respectively achieves the disconnection and isolation of AC and DC, thereby protecting the safety of maintenance personnel. If transformers are not used to simultaneously draw power from AC and DC, the AC and DC sides cannot be effectively isolated, creating potential safety risks during maintenance of the connection between the third disconnecting switch K2 and the AC / DC conversion unit 11.

[0071] The charging circuit of this invention can connect the control system of the photovoltaic-storage-charging hybrid system and the vehicle control system. The charging gun, DC battery 12, battery input source 152, and photovoltaic input source 151 all have sampling circuits for voltage and current. Therefore, there must be sufficient reinforced insulation between the charging gun, DC battery 12, battery input source 152, photovoltaic input source 151 and the control system, as well as between the DC battery 12 and the charging gun, between the photovoltaic input source 151 and the charging gun, and between the battery input source 152 and the charging gun. The 1000V system requires a 10mm reinforced insulation isolation requirement. When designing reinforced insulation, the number of resistors must not only meet the distance requirements for reinforced insulation but also the power consumption requirements for pulse voltage and withstand voltage tests. The 1500V system requires a 15mm distance requirement and power consumption requirements for pulse voltage and withstand voltage tests. To reduce device costs and increase the range of device options, and to improve the reliability of electrical insulation, the entire isolation circuit for the 1500V system should be potted with a compliant solid insulating adhesive to achieve solid insulation design.

[0072] Especially for high-impedance isolation circuits, the distance between resistors should be at least (N-1) * the distance of a single resistor. Furthermore, in the design of ground insulation impedance detection, the number of resistors that are closed and shorted by the switching device is not considered as a design for reducing the distance of the resistor insulation.

[0073] In the design of enhanced insulation between the 220V circuit and the control circuit, the 220V circuit needs to supply power to the 220V isolation power module after the system lightning protection, so as to achieve enhanced insulation isolation of the control circuit.

[0074] In one embodiment, the DC port and AC port of the charging circuit further include an insulating capacitor.

[0075] Specifically, for a 1500V DC port (referring to the port used to output DC signals in the charging circuit, such as the output port of DC battery 12, the output port of photovoltaic input source 151, the output port of battery input source 152, etc.), the insulating capacitor is, for example, a capacitor of the first insulation class (denoted as Y1 capacitor) or a capacitor of the second insulation class (denoted as Y2 capacitor). In a specific embodiment, the insulating capacitor includes two Y1 capacitors or Y2 capacitors connected in series. The insulation class of the Y1 capacitor is higher than that of the Y2 capacitor. The insulation class of the Y1 capacitor is generally 8000V, and the insulation class of the Y2 capacitor is generally 4000V.

[0076] For the 1000V DC port of an isolated AC / DC converter, the insulation capacitor is a Y1 capacitor, which can be a single Y1 capacitor or two Y1 capacitors connected in series. For the AC port with a phase voltage of less than 300V, due to the surge protection module design at the front end of the system, the insulation capacitor of the AC port of the AC / DC converter (such as the mains output port) is, for example, a Y2 capacitor.

[0077] For non-isolated AC / DC converters with voltages below 500V, the insulation capacitor of the AC port (such as the grid output port) is generally a Y1 capacitor, and at least one Y1 capacitor is connected to the grounded casing to achieve isolation from ground.

[0078] For non-isolated AC / DC converters with voltages above 500V and hybrid systems of optical storage and charging, the insulation capacitors of the AC ports (such as the grid output port) are generally two Y1 capacitors or Y2 capacitors connected in series. They are connected in series with at least two Y1 capacitors or at least two Y2 capacitors and then connected to the grounded casing to achieve isolation from the ground.

[0079] For 1000V / 1500V reinforced insulation isolation transformers (located in isolated AC / DC converters), the primary and secondary creepage distances must meet the requirements (e.g., 20 / 30mm). The primary and secondary coils should use membrane-wrapped wire, and the width of the insulating tape should also meet the requirements, e.g., 20 / 30mm. The number of tape layers should be at least 3, calculated based on the operating voltage and frequency. The transformer can achieve the minimum required distance (e.g., 10 / 15mm high) by raising it on an epoxy board, or by simultaneously potting the bottom transformer pins with the appropriate thickness and standard potting compound to reduce contamination and meet the safety distance design requirements for contamination levels. Alternatively, it can meet the safety distance requirements for solid insulation.

[0080] Optocouplers are surface-mount soldered onto the PCB. For 1000 / 1500V systems, the PCB needs to meet reinforced insulation wiring distance requirements (e.g., 10 / 30mm). Due to the limitations of the optocoupler itself, especially in 1500V systems, the minimum safe distance between the optocouplers needs to be greater than a preset distance, such as 11mm, and the optocouplers should be potted with standard-compliant potting compound to achieve solid insulation design requirements. For 1000V systems, the optocouplers should be selected to be larger than a predetermined size, such as 6.4mm, and potted with standard-compliant solid insulating compound to achieve solid insulation design requirements.

[0081] Based on the application scenarios of integrated photovoltaic, energy storage and charging systems, especially in 1500V applications, the PCB material can be selected according to the actual situation. Under the condition that the layout and wiring allow, the reliability of electrical insulation can be improved and the application of potting compound can be reduced.

[0082] In both the photovoltaic and energy storage battery fields, insulation resistance testing of the DC side is required, and the insulation resistance must be greater than the system's highest voltage / preset current (e.g., 30mA).

[0083] In the field of 1000V charging systems, the typical charging voltage is 200-1000V, so the range of protection impedance is 20kΩ-100kΩ. That is, in a 1000V system, if the insulation impedance to ground is less than the first preset impedance of 33.3kΩ, the system will shut down for protection. The incompatibility protection range between 1000V charging and photovoltaic / energy storage systems is 20kΩ-33.3kΩ. Assuming the system's insulation impedance to ground is 30kΩ, there is a possibility that the charging system is continuing to charge, but the photovoltaic and energy storage power supply systems have already failed and shut down. To ensure compatibility of protection functions, the protection values ​​for charging and photovoltaic / energy storage functions are normalized. The minimum protection impedance, i.e., the first preset impedance, is defined as 33.3kΩ, which not only ensures compatibility with protection thresholds but also improves the safety level.

[0084] In the field of 1500V charging systems, the typical charging voltage is 200-1500V, so the range of the protective impedance is 20kΩ-150kΩ. That is, in a 1500V system, if the insulation resistance to ground is less than the second preset impedance, such as 50kΩ, the system protection will shut down. In a 1500V system, the minimum protective impedance, i.e., the second preset impedance, is increased to 50kΩ.

[0085] In a photovoltaic-storage-charging hybrid system, protection functions should also be configured according to the charging system to enable system shutdown protection in the event of poor grounding, ensuring the safety of operators. In a photovoltaic-storage-charging hybrid system, protection devices should also be configured according to the charging system to be compatible with a wider range of AC / DC converter primary coil to ground basic insulation designs, especially the system's distribution network, thereby further improving the safety level of the entire system.

[0086] The charging circuit of this utility model integrates energy storage and charging, optical energy storage and optical energy storage and charging, and designs switching devices in the charging circuit to achieve insulation design of each working node, making the product safer and more reliable in use.

[0087] See Figure 5 , Figure 5 This is a schematic diagram of the structure of a charging pile according to an embodiment of the present invention. The charging pile 100 includes a charging circuit 10, which is the charging circuit shown in any embodiment.

[0088] The above are merely embodiments of this utility model and do not limit the scope of patent protection of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this utility model.

Claims

1. A charging circuit, characterized in that, include: DC battery, AC / DC conversion unit, charging path, energy input unit; The AC / DC conversion unit is connected between the power grid and the DC battery, and the energy input unit is connected to the DC battery. The DC battery and the energy input unit are connected to the charging path; An insulating component is provided on the path connecting the energy input unit and the DC battery. The energy input unit includes a photovoltaic input source and a battery input source; Insulating components are provided on the pathways connecting the photovoltaic input source and the battery input source to the DC battery; The photovoltaic input source and the battery input source are respectively connected to the charging path; The insulating components include: a first switch assembly and a second switch assembly; In the path connecting the photovoltaic input source and the DC battery, the first end of the first switch assembly is connected to the DC battery, the second end of the first switch assembly is connected to the first end of the second switch assembly, and the second end of the second switch assembly is connected to the photovoltaic input source. In the path connecting the battery input source and the DC battery, the first end of the first switch assembly is connected to the DC battery, the second end of the first switch assembly is connected to the first end of the second switch assembly, and the second end of the second switch assembly is connected to the battery input source.

2. The charging circuit according to claim 1, characterized in that, The photovoltaic input source, the battery input source, and the DC battery are connected to the DC bus, and the charging path is connected through the DC bus.

3. The charging circuit according to claim 1, characterized in that, The charging path includes: a first charging path, a second charging path, and a first switching unit connecting the first charging path and the second charging path; The DC battery is connected to the first charging path and the second charging path, the photovoltaic input source is connected to the first charging path, and the battery input source is connected to the second charging path.

4. The charging circuit according to claim 3, characterized in that, The first charging path includes: a first conversion unit, a second switching unit, and a first charging gun connected in series; the second charging path includes: a second conversion unit, a third switching unit, and a second charging gun connected in series. Wherein, the first end of the first switching unit is connected to the first node between the first conversion unit and the second switching unit, the second end of the first switching unit is connected to the second node between the second conversion unit and the third switching unit; and the photovoltaic input source is connected to the first conversion unit, and the battery input source is connected to the second conversion unit.

5. The charging circuit according to claim 1, characterized in that, The AC / DC conversion unit includes a first disconnect switch and a current conversion module, wherein the first disconnect switch is connected between the AC terminal of the AC / DC conversion unit and the current conversion module.

6. The charging circuit according to claim 5, characterized in that, The connection path between the AC / DC conversion unit and the power grid also includes: A second disconnecting switch is connected between the power grid and the AC terminal of the AC / DC conversion unit; and / or The third isolating switch is connected between the second isolating switch and the AC terminal of the AC / DC conversion unit.

7. The charging circuit according to claim 1, characterized in that, The DC and AC ports of the charging circuit also include insulating capacitors.

8. The charging circuit according to claim 1, characterized in that, The charging circuit further includes a control unit, which is connected between the AC terminal of the AC / DC conversion unit and the DC terminal of the AC / DC conversion unit. The control unit includes a control circuit, a first transformer, and a second transformer. The control circuit is connected to the AC terminal of the AC / DC conversion unit through the first transformer, and the control circuit is connected to the DC terminal of the AC / DC conversion unit through the second transformer.

9. A charging pile, characterized in that, Includes the charging circuit described in any one of claims 1 to 8.

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