Charging module and charging system

Abstract

The utility model discloses a charging module and a charging system, and relates to the technical field of power electronics. The charging module comprises a conversion circuit, at least one absorption protection circuit and a module output circuit, the absorption protection circuit comprises a first switch unit, a second switch unit, a third switch unit, a first protection unit and a second protection unit, the first protection unit comprises a first diode and / or a first capacitor, and the second protection unit comprises a second diode and / or a second capacitor. Therefore, when the voltage withstanding test of the output of the charging module on the protective grounding conductor is carried out, the safe operation of the rectifier bridge in the post-stage DC conversion circuit is ensured, and the reliability of the charging module is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and particularly relates to a charging module and a charging system. BACKGROUND

[0002] With the development of electric vehicles, the related test specifications for electric vehicles are becoming more and more strict and normative. Among them, in the dielectric strength and impulse withstand voltage detection projects of the charging module, the withstand voltage values applied between each independent live circuit of the module electrical connection and between each independent live circuit and the protective grounding conductor (metal shell) are explicitly specified. These provisions aim to ensure that the electrical system can operate stably in a high-voltage environment and avoid safety accidents caused by insulation failure.

[0003] However, in the actual test process, especially in the process of testing the withstand voltage of the charging module output to the protective grounding conductor (PE), the rectifier diode in the rear-stage DC conversion circuit often experiences high-voltage breakdown damage events. However, lightning overvoltage, operating overvoltage and similar working conditions often occur and are unavoidable in the actual working environment of the charging module. Therefore, it is necessary to improve the corresponding circuit structure. SUMMARY

[0004] The main purpose of the present application is to provide a charging module and a charging system to ensure the safe operation of the rectifier bridge in the rear-stage DC conversion circuit when testing the withstand voltage of the charging module output to the protective grounding conductor, and to improve the reliability of the charging module.

[0005] To achieve the above purpose, the present application provides a charging module, which comprises a conversion circuit, at least one absorption protection circuit and a module output circuit.

[0006] The conversion circuit is connected with the module output circuit, and the conversion circuit comprises at least one group of DC output ends, each group of DC output ends comprises a first end, a second end, a third end and a fourth end, and each absorption protection circuit is connected with a corresponding DC output end.

[0007] The absorption protection circuit comprises a first switching unit, a second switching unit, a third switching unit, a first protection unit and a second protection unit, the first protection unit comprises a first diode and / or a first capacitor, and the second protection unit comprises a second diode and / or a second capacitor.

[0008] The first switch unit is connected in parallel between the first end and the third end of the DC output end, the second switch unit is connected in parallel between the second end and the fourth end of the DC output end, the first connection end of the third switch unit is connected with the second end and grounded after connection, the second connection end of the third switch unit is connected with the third end and grounded after connection, the first protection unit is connected in parallel across the first switch unit, and the second protection unit is connected in parallel across the second switch unit.

[0009] Optionally, the first protection unit comprises a first diode and a first capacitor, the first diode is connected in parallel across the first switch unit, and the first capacitor is connected in parallel across the first diode; the second protection unit comprises a second diode and a second capacitor, the second diode is connected in parallel across the second switch unit, and the second capacitor is connected in parallel across the second diode.

[0010] Optionally, the third switch unit comprises a third relay and a fourth relay; one end of the third relay is connected with the second end of the DC output end, and the other end of the third relay is connected with the module output circuit; one end of the fourth relay is connected with the third end of the DC output end, and the other end of the fourth relay is connected with the module output circuit.

[0011] Optionally, the third switch unit comprises a third relay, one end of the third relay is connected with the second end of the DC output end and connected with the module output circuit, and the other end of the third relay is connected with the third end of the DC output end and connected with the module output circuit.

[0012] Optionally, the absorption protection circuit further comprises a first resistor and a second resistor; the first resistor is connected in series between the first switch unit and the first protection unit; and the second resistor is connected in series between the second switch unit and the second protection unit.

[0013] Optionally, the absorption protection circuit further comprises a third capacitor and a fourth capacitor; the third capacitor is connected in parallel between the first end and the second end of the DC output end; and the fourth capacitor is connected in parallel between the third end and the fourth end of the DC output end.

[0014] Optionally, the conversion circuit comprises an AC / DC conversion module and at least one set of transformer rectification modules, the AC / DC conversion module being connected with each of the transformer rectification modules; each of the transformer rectification modules comprises a first transformer, a second transformer, a first rectification unit and a second rectification unit; the primary end of the first transformer is connected with the AC / DC conversion module, and the secondary end of the first transformer is connected with the first rectification unit; the primary end of the second transformer is connected with the AC / DC conversion module, and the secondary end of the second transformer is connected with the second rectification unit; the first output end of the first rectification unit serves as a first end of the DC output end, and the second output end of the first rectification unit serves as a second end of the DC output end; the first output end of the second rectification unit serves as a third end of the DC output end, and the second output end of the second rectification unit serves as a fourth end of the DC output end.

[0015] Optionally, the first rectification unit comprises a third diode, a fourth diode, a fifth diode and a sixth diode; the anode of the third diode is connected with the cathode of the fourth diode to serve as an input end of the first rectification unit, the anode of the fifth diode is connected with the cathode of the sixth diode to serve as another input end of the first rectification unit, the cathode of the third diode is connected with the cathode of the fifth diode to serve as a first output end of the first rectification unit, and the anode of the fourth diode is connected with the anode of the sixth diode to serve as a second output end of the first rectification unit; the second rectification unit comprises a seventh diode, an eighth diode, a ninth diode and a twelfth diode; the anode of the seventh diode is connected with the cathode of the eighth diode to serve as an input end of the second rectification unit, the anode of the ninth diode is connected with the cathode of the twelfth diode to serve as another input end of the second rectification unit, the cathode of the seventh diode is connected with the cathode of the ninth diode to serve as a first output end of the second rectification unit, and the anode of the eighth diode is connected with the anode of the twelfth diode to serve as a second output end of the second rectification unit.

[0016] Optionally, the module output circuit comprises an anti-reverse diode and at least one output unit, each of the output units being connected with one of the absorption protection circuits; the first input end of any of the output units is connected with the first end of the corresponding DC output end, the second input end is connected with the fourth end of the corresponding DC output end, the third input end is connected with the third connection end of the third switch unit in the corresponding absorption protection circuit, the first output end is connected with the anode of the anti-reverse diode, and the second output end is connected with the negative end of a load; the cathode of the anti-reverse diode is connected with the positive end of the load.

[0017] In addition, to achieve the above objectives, this application also provides a charging system including at least one charging module as described above.

[0018] The charging module of this application, during withstand voltage testing, disconnects the first, second, and third switching units of the absorption protection circuit, and provides a freewheeling path for the high voltage applied to the rectifier bridge through the first and second protection units. This absorbs the high voltage applied to the rectifier bridge, thereby reducing the voltage of the rectifier bridge and preventing the rectifier diodes in the rectifier bridge from being damaged by high voltage. This ensures the safe operation of the rectifier bridge in the subsequent DC conversion circuit and improves the reliability of the charging module. Attached Figure Description

[0019] Figure 1 This is a circuit diagram of a charging module using existing technology;

[0020] Figure 2 This is one of the circuit diagrams of the charging module in an embodiment of this application;

[0021] Figure 3 This is a circuit diagram of an example charging module of this application;

[0022] Figure 4 This is a circuit diagram of the charging module of the second example of this application;

[0023] Figure 5 This is a second circuit diagram of the charging module according to an embodiment of this application;

[0024] Figure 6 This is the third circuit diagram of the charging module in this application embodiment;

[0025] Figure 7 This is the fourth circuit diagram of the charging module in the embodiment of this application;

[0026] Figure 8 This is a circuit diagram of the charging module of the third example of this application;

[0027] Figure 9 This is the fifth circuit diagram of the charging module in the embodiments of this application;

[0028] In the diagram, 100 is the conversion circuit; 110 is the AC / DC conversion module; 120 is the transformer and rectifier module; 200 is the absorption protection circuit; 210 is the first switching unit; 220 is the second switching unit; 230 is the third switching unit; 240 is the first protection unit; 250 is the second protection unit; and 300 is the module output circuit.

[0029] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] The dielectric strength and impulse withstand voltage tests for charging modules typically include: impulse withstand voltage tests between the charging module input and output, and impulse withstand voltage tests between the charging module output and the protective grounding conductor (metal casing PE). In actual testing, a positive or negative pulse is applied between the two terminals being tested (e.g., the charging module output and PE). However, during testing, the rectifier diodes in the subsequent DC conversion circuit often experience high-voltage breakdown damage, and the location of the damaged diodes is random.

[0032] Figure 1 This is a circuit diagram of a charging module based on existing technology, for reference. Figure 1 Analysis revealed that the main reason for the rectifier diode failure was that the Y capacitor C1-1 to ground in the front-stage AC / DC converter module, the Y capacitor C1-2 to ground in the rear-stage DC converter circuit, and the withstand voltage tester formed a loop. Furthermore, the Y capacitor C1-2 to ground in the rear-stage DC converter circuit had a much smaller capacitance than the Y capacitor C1-1 to ground in the front-stage AC / DC converter module. Therefore, the Y capacitor C1-2 would bear a higher voltage Vdc. Parasitic capacitances (e.g., between rectifier bridges) typically exist between the rectifier bridges. Figure 1 Parasitic capacitances (such as C1-3 and C1-5 in the rectifier bridge) also exist between the rectifier bridge and ground (e.g., C1-3 and C1-5 in the rectifier bridge). Figure 1 (C1-4 and C1-6 in the diagram). These two capacitors, connected in series, divide the voltage to Vdc, resulting in a relatively high voltage. It's important to note that parasitic capacitance refers to the capacitive effect that exists in electronic circuits despite not being intentionally designed in.

[0033] Furthermore, since the parasitic capacitances between rectifier bridges (C1-3 and C1-5) are typically larger than the parasitic capacitances between the rectifier bridge and ground (C1-4 and C1-6), a larger capacitance results in a greater voltage drop. Therefore, due to the larger voltage drop caused by the parasitic capacitances between rectifier bridges (C1-3 and C1-5), the rectifier bridges experience a higher voltage, which may lead to damage.

[0034] If the electrolytic capacitor at the output of the charging module (for example) Figure 1In this configuration, C1-7 and C1-8 are placed before the output relay. The electrolytic capacitors can absorb some of the voltage spikes from the impulse withstand voltage. However, if the capacitance of each electrolytic capacitor is denoted as Co, during the series-parallel combination of the output relays, for low-voltage outputs below 500V, the total output electrolytic capacitor capacitance after the two output electrolytic capacitors are connected in parallel is denoted as 2Co. For high-voltage outputs above 500V and below 1000V, the total output electrolytic capacitor capacitance after the two output electrolytic capacitors are connected in series is denoted as Co / 2. This combination structure of different capacitors for high and low voltages results in a difference of more than 4 times in the total output capacitance, which brings great challenges to the loop design on the DC side. The dual-loop switching further complicates the software code design.

[0035] Therefore, in practical applications, the electrolytic capacitor at the output of the charging module is usually placed after the output relay. Because of this, the output electrolytic capacitor is not placed in parallel with the output rectifier diode. During impulse withstand voltage testing, it fails to absorb voltage spikes from the impulse withstand voltage, causing rectifier diode failure and affecting the reliable operation of the module and the entire charging pile. However, lightning overvoltage and switching overvoltage conditions occur frequently and are unavoidable in the actual operating environment of charging modules. Therefore, improving the corresponding circuit structure to absorb voltage spikes applied to the rectifier diode is essential.

[0036] Based on this, embodiments of this application provide a charging module and a charging system. By adding an absorption protection circuit to the charging module, the absorption protection circuit absorbs some of the voltage spikes from the impulse withstand voltage, thereby ensuring the safe operation of the rectifier bridge in the subsequent DC conversion circuit and improving the reliability of the charging module.

[0037] Figure 2 This is one of the circuit diagrams of the charging module according to an embodiment of this application. For example... Figure 2 As shown, the charging module may include a conversion circuit 100, at least one absorption protection circuit 200, and a module output circuit 300; the conversion circuit 100, each absorption protection circuit 200, and the module output circuit 300 are interconnected.

[0038] The conversion circuit 100 is connected to the module output circuit 300. The conversion circuit 100 includes at least one set of DC output terminals. Each set of DC output terminals includes a first terminal S1, a second terminal S2, a third terminal S3, and a fourth terminal S4. Each absorption protection circuit 200 is connected to a corresponding DC output terminal.

[0039] The absorption protection circuit 200 includes a first switching unit 210, a second switching unit 220, a third switching unit 230, a first protection unit 240, and a second protection unit 250. The first protection unit 240 includes a first diode D1 and / or a first capacitor C1, and the second protection unit 250 includes a second diode D2 and / or a second capacitor C2.

[0040] The first switch unit 210 is connected in parallel between the first terminal S1 and the third terminal S3 of the DC output terminal. The second switch unit 220 is connected in parallel between the second terminal S2 and the fourth terminal S4 of the DC output terminal. The first connection terminal of the third switch unit 230 is connected to the second terminal S2 and then grounded. The second connection terminal of the third switch unit 230 is connected to the third terminal S3 and then grounded. The first protection unit 240 is connected in parallel across the two ends of the first switch unit 210. The second protection unit 250 is connected in parallel across the two ends of the second switch unit 220.

[0041] First, it should be noted that the circuit structure of a charging module typically consists of a pre-stage PFC (i.e., AC / DC conversion module) and a DC / DC conversion module (i.e., the transformer and rectifier module in this embodiment). The PFC section rectifies the input three-phase mains power into approximately ±420V DC, with a total voltage of 840V. It further uses a large-capacity electrolytic capacitor for voltage regulation and filtering. The DC / DC conversion module uses two or more LLC resonant cavities for conversion and output. At the output end, a series and parallel combination of relays is used to achieve a wide range of output voltage from 50V to 1000V.

[0042] In this embodiment, the charging module includes a conversion circuit 100, which comprises the aforementioned front-end PFC section and a rear-end DC / DC conversion module. The DC / DC conversion module has multiple rectifier bridges (i.e., the first rectifier unit or the second rectifier unit described in subsequent embodiments). Specifically, the output of the conversion circuit 100 in this embodiment is the output of each rectifier bridge. The outputs of two sets of rectifier bridges can be used as a group of DC output terminals. Therefore, a group of DC output terminals has four connection terminals: a first terminal S1, a second terminal S2, a third terminal S3, and a fourth terminal S4. Furthermore, each group of DC output terminals can be connected to the module output circuit 300.

[0043] It should be noted that the number of rectifier bridges in the converter circuit 100 is an even number, and the minimum number of rectifier bridges is two. For example, the converter circuit 100 may include two sets of rectifier bridges or four sets of rectifier bridges. Correspondingly, two sets of rectifier bridges correspond to one set of DC output terminals. Therefore, if the converter circuit 100 includes 2n sets of rectifier bridges, then the number of DC output terminals is n. For example, if the converter circuit 100 includes four sets of rectifier bridges, then the converter circuit 100 includes two sets of DC output terminals.

[0044] In this embodiment, the charging module may include multiple absorption protection circuits 200, and different absorption protection circuits 200 are connected to different DC output terminals. Therefore, the number of absorption protection circuits 200 is also determined by the number of rectifier bridges, and the number of absorption protection circuits 200 is the same as the number of DC output terminals.

[0045] Continue to refer to Figure 2 Taking an absorption protection circuit 200 as an example, the absorption protection circuit 200 may include a first switching unit 210, a second switching unit 220, a third switching unit 230, a first protection unit 240, and a second protection unit 250. The first switching unit 210 is connected in parallel between the first terminal S1 and the third terminal S3 of the DC output, meaning that both ends of the first switching unit 210 are connected to the output terminals of the two rectifier bridges respectively. Similarly, the second switching unit 220 is connected in parallel between the second terminal S2 and the fourth terminal S4 of the DC output, meaning that both ends of the second switching unit 220 are connected to the output terminals of the two rectifier bridges respectively.

[0046] The first connection terminal of the third switching unit 230 is connected to the second terminal S2, and the connection between the first connection terminal and the second terminal S2 is grounded. The second connection terminal of the third switching unit 230 is connected to the third terminal S3, and the connection between the second connection terminal and the third terminal S3 is grounded. It should be noted that parasitic capacitances typically exist between rectifier bridges and between rectifier bridges and ground. Figure 2 The image only shows the parasitic capacitance between the rectifier bridge and ground, namely the first parasitic capacitance CS1 and the second parasitic capacitance CS2.

[0047] In this embodiment, the first protection unit 240 and the second protection unit 250 may include electronic components with freewheeling absorption function, such as diodes, capacitors, etc.

[0048] The module output circuit 300 is the output circuit of the charging module, and it is connected to the load. It can be understood that when the charging module's input AC port is subjected to a high-voltage surge test to the output DC port, or when the charging module's DC port is subjected to a high-voltage surge test to the PE (safety grounding enclosure), it can be equivalent to charging the Y capacitor between the charging module's DC port and PE, and then releasing the high voltage. During the high-voltage withstand test, the positive and negative terminals of the load are usually shorted together. At the instant the charging module's DC port releases energy to the Y capacitor between PE, the positive and negative terminals of the load are shorted again through the electrolytic capacitor on the output side.

[0049] Based on the circuit structure of the charging module in this embodiment, during the withstand voltage test of the charging module output to PE, the protection principle of the first protection unit 240 and the second protection unit 250 for the rectifier bridge is as follows:

[0050] When the charging module outputs a positive pulse impact on PE, the positive and negative terminals of the load are shorted together. The positive pulse flows from the negative terminal of the load through the second protection unit 250, then flows out from the second protection unit 250, and after passing through the first parasitic capacitor CS1, it flows into PE.

[0051] When the charging module outputs a negative pulse impact on PE, the negative polarity pulse first flows out from the second parasitic capacitor CS2, then flows through the first protection unit 240 to the positive terminal of the load. It should be noted that before performing the withstand voltage test, the first switching unit 210, the second switching unit 220, and the third switching unit 230 must all be in the off state.

[0052] Therefore, the first protection unit 240 and the second protection unit 250 provide a path for the high voltage pulse during the withstand voltage test, which reduces the voltage applied to the rectifier bridge and absorbs the high voltage spike. This prevents the rectifier bridge in the converter circuit 100 from being damaged by high voltage, ensuring the safe operation of the rectifier bridge in the subsequent DC converter circuit 100 and improving the reliability of the charging module.

[0053] In some embodiments, the first switching unit 210 and the second switching unit 220 may each include a relay, and the third switching unit 230 may include two relays. The structure and connection relationship of the first switching unit 210, the second switching unit 220, and the third switching unit 230 will be described in detail below through an example.

[0054] Figure 3 This is a circuit diagram of an example charging module of this application. Figure 3 As shown, the first switching unit 210 includes a first relay K1, the second switching unit 220 includes a second relay K2, and the third switching unit 230 includes a third relay K3 and a fourth relay K4.

[0055] Specifically, one end of the first relay K1 is connected to the first terminal S1 of a DC output terminal, and the other end of the first relay K1 is connected to the third terminal S3 of the DC output terminal. One end of the second relay K2 is connected to the second terminal S2 of the DC output terminal, and the other end of the second relay K2 is connected to the fourth terminal S4 of the DC output terminal. One end of the third relay K3 is connected to the second terminal S2 of the DC output terminal, and the other end of the third relay K3 is connected to the module output circuit 300. One end of the fourth relay K4 is connected to the third terminal S3 of the DC output terminal, and the other end of the fourth relay K4 is connected to the module output circuit 300.

[0056] Furthermore, the first protection unit 240 can be connected in parallel across the two ends of the first relay K1, and the second protection unit 250 can be connected in parallel across the two ends of the second relay K2. During the withstand voltage test, the first relay K1, the second relay K2, the third relay K3, and the fourth relay K4 all remain in the open state.

[0057] In some embodiments, the third switching unit 230 may include a relay. The following example provides a detailed description of the structure and connection relationships of another type of third switching unit 230.

[0058] Figure 4 This is a circuit diagram of the charging module of the second example of this application. (See diagram below.) Figure 4 As shown, the third switching unit 230 includes a third relay K3.

[0059] One end of the third relay K3 is connected to the second terminal S2 of the DC output terminal, and the other end of the third relay K3 is connected to the third terminal S3 of the DC output terminal. Simultaneously, both ends of the third relay K3 are also connected to the module output circuit 300.

[0060] This application provides three different structures for the first protection unit 240 and the second protection unit 250, which will be described in detail below.

[0061] Figure 5 This is a second circuit diagram of the charging module according to an embodiment of this application. Figure 5 As shown, in some embodiments, the first protection unit 240 includes a first diode D1, which is connected in parallel across the two ends of the first switching unit 210; the second protection unit 250 includes a second diode D2, which is connected in parallel across the two ends of the second switching unit 220.

[0062] Taking the first switching unit 210 including a first relay K1 and the second switching unit 220 including a second relay K2 as an example, the cathode of the first diode D1 can be connected to one end of the first relay K1, and this end of the first relay K1 is connected to the first terminal S1 of the DC output terminal; the anode of the first diode D1 can be connected to the other end of the first relay K1, and this end of the first relay K1 is connected to the third terminal S3 of the DC output terminal.

[0063] Similarly, the cathode of the second diode D2 can be connected to one end of the second relay K2, which is connected to the second terminal S2 of the DC output terminal; the anode of the second diode D2 can be connected to the other end of the second relay K2, which is connected to the fourth terminal S4 of the DC output terminal.

[0064] In this embodiment, when the charging module outputs a positive pulse impact on the PE, and the positive pulse passes through the second protection unit 250, the second diode D2 not only absorbs the high voltage spike applied to the rectifier bridge, but also provides a certain degree of freewheeling current. Similarly, when the charging module outputs a negative pulse impact on the PE, and the negative pulse passes through the first protection unit 240, the first diode D1 not only absorbs the high voltage spike applied to the rectifier bridge, but also provides a certain degree of freewheeling current.

[0065] Figure 6 This is the third circuit diagram of the charging module in an embodiment of this application. Figure 6 As shown, in some embodiments, the first protection unit 240 includes a first capacitor C1, which is connected in parallel across the two ends of the first switching unit 210; the second protection unit 250 includes a second capacitor C2, which is connected in parallel across the two ends of the second switching unit 220.

[0066] Taking the example of the first switching unit 210 including the first relay K1 and the second switching unit 220 including the second relay K2, the first capacitor C1 can be connected in parallel across the two ends of the first relay K1, and the second capacitor C2 can be connected in parallel across the two ends of the second relay K2.

[0067] It should be noted that both the first capacitor C1 and the second capacitor C2 can be film capacitors.

[0068] In this embodiment, when the charging module outputs a positive pulse impact on the PE, and the positive pulse passes through the second protection unit 250, the second capacitor C2 not only absorbs the high voltage spike applied to the rectifier bridge, but also provides a certain amount of follow current. Similarly, when the charging module outputs a negative pulse impact on the PE, and the negative pulse passes through the first protection unit 240, the first capacitor C1 not only absorbs the high voltage spike applied to the rectifier bridge, but also provides a certain amount of follow current.

[0069] Figure 7 This is the fourth circuit diagram of the charging module according to an embodiment of this application. Figure 7 As shown, in some embodiments, the first protection unit 240 includes a first diode D1 and a first capacitor C1, the first diode D1 being connected in parallel across the two ends of the first switching unit 210, and the first capacitor C1 being connected in parallel across the two ends of the first diode D1; the second protection unit 250 includes a second diode D2 and a second capacitor C2, the second diode D2 being connected in parallel across the two ends of the second switching unit 220, and the second capacitor C2 being connected in parallel across the two ends of the second diode D2.

[0070] Taking the example of the first switching unit 210 including the first relay K1 and the second switching unit 220 including the second relay K2, the cathode of the first diode D1 can be connected to one end of the first relay K1, which is connected to the first terminal S1 of the DC output; the anode of the first diode D1 can be connected to the other end of the first relay K1, which is connected to the third terminal S3 of the DC output. Furthermore, the first capacitor C1 can be connected in parallel across the first diode D1.

[0071] Similarly, the cathode of the second diode D2 can be connected to one end of the second relay K2, which is connected to the second terminal S2 of the DC output; the anode of the second diode D2 can be connected to the other end of the second relay K2, which is connected to the fourth terminal S4 of the DC output. Furthermore, the second capacitor C2 can be connected in parallel across the two ends of the second diode D2.

[0072] In this embodiment, when the charging module outputs a positive pulse impact on PE, the positive pulse, upon passing through the second protection unit 250, improves the absorption and freewheeling capabilities of the second protection unit 250 through the parallel connection of the second diode D2 and the second capacitor C2. Furthermore, during withstand voltage testing, the second capacitor C2 can share some of the high-voltage spikes with the second diode D2, thus protecting the second diode D2. Therefore, this parallel combination of the second diode D2 and the second capacitor C2 protects both the rectifier bridge and prevents damage to the second protection unit 250 itself, enhancing its protection capability and reliability.

[0073] It should be noted that the first protection unit 240 and the second protection unit 250 have the same structure and protection principle, which will not be described again here.

[0074] In some embodiments, the absorption protection circuit 200 may further include a first resistor R1 and a second resistor R2. The first resistor R1 is connected in series between the first switching unit 210 and the first protection unit 240; the second resistor R2 is connected in series between the second switching unit 220 and the second protection unit 250.

[0075] Specifically, the first resistor R1 can be connected between the first switching unit 210 and the first protection unit 240, and the second resistor R2 can be connected between the second switching unit 220 and the second protection unit 250. The first resistor R1 is a current-limiting resistor, which can adjust the current absorption capacity and absorption speed of the first protection unit 240; similarly, the second resistor R2 is also a current-limiting resistor, which can adjust the current absorption capacity and absorption speed of the second protection unit 250.

[0076] As an example, if it is necessary to reduce the current absorption capacity of the first protection unit 240, a resistor with a larger resistance value can be selected as the first resistor R1. The larger the resistance value of the first resistor R1, the smaller the current in the follow-through path from PE to the load, and the less current is absorbed, thus weakening the ability of this follow-through path to absorb high-side spikes. Similarly, if it is necessary to enhance the current absorption capacity of the second protection unit 250, a resistor with a smaller resistance value can be selected as the second resistor R2. The smaller the resistance value of the second resistor R2, the larger the current in the follow-through path from the load to PE, and the more current is absorbed, thus enhancing the ability of this follow-through path to absorb high-side spikes.

[0077] Therefore, by setting a first resistor R1 and a second resistor R2 in the absorption protection circuit 200, the ability and speed of the first protection unit 240 and the second protection unit 250 to absorb current can be adjusted by adjusting the resistance values ​​of the first resistor R1 and the second resistor R2, thereby improving the flexibility of the absorption protection circuit 200.

[0078] Figure 8 This is a circuit diagram of the charging module of the third example of this application. The connection relationship between the first resistor R1 and the second resistor R2 will be described in detail below, taking as an example that the first switching unit 210 includes a first relay K1, the second switching unit 220 includes a second relay K2, the first protection unit 240 includes a first diode D1 and a first capacitor C1, and the second protection unit 250 includes a second diode D2 and a second capacitor C2.

[0079] like Figure 8 As shown, one end of the first resistor R1 can be connected to one end of the first relay K1, the other end of the first resistor R1 is connected to the cathode of the first diode D1, the anode of the first diode D1 can be connected to the other end of the first relay K1, and the first capacitor C1 can be connected in parallel across the two ends of the first diode D1.

[0080] Similarly, one end of the second resistor R2 can be connected to one end of the second relay K2, the other end of the second resistor R2 can be connected to the cathode of the second diode D2, the anode of the second diode D2 can be connected to the other end of the second relay K2, and the second capacitor C2 can be connected in parallel across the two ends of the second diode D2.

[0081] During the withstand voltage test of the charging module output to PE based on this embodiment, the pulse flow process is as follows:

[0082] When the charging module outputs a positive pulse impact on PE, the positive and negative terminals of the load are shorted together. The positive pulse flows from the negative terminal of the load into the second diode D2, then flows out from the cathode of the second diode D2, passes through the second resistor R2, and then flows into PE through the first parasitic capacitance CS1 between the upper rectifier bridge and ground.

[0083] When the charging module outputs a negative pulse impact on PE, the negative pulse first flows from the second parasitic capacitor CS2 to the first diode D1, then flows from the cathode of the first diode D1, passes through the first resistor R1, and flows to the positive terminal of the load.

[0084] Figure 9 This is the fifth circuit diagram of the charging module according to an embodiment of this application. Figure 9 As shown, in some embodiments, the absorption protection circuit 200 further includes a third capacitor C3 and a fourth capacitor C4; the third capacitor C3 is connected in parallel between the first terminal S1 and the second terminal S2 of the DC output terminal; the fourth capacitor C4 is connected in parallel between the third terminal S3 and the fourth terminal S4 of the DC output terminal.

[0085] It should be noted that the third capacitor C3 and the fourth capacitor C4 can be film capacitors. The capacitance of film capacitors is usually larger than that of parasitic capacitors but smaller than that of electrolytic capacitors.

[0086] In this embodiment, the third capacitor C3 and the fourth capacitor C4 are located at the output end of the rectifier bridge. They can be used for filtering and stabilizing the voltage, and can also absorb the voltage of the rectifier bridge to a certain extent, preventing damage to subsequent circuits due to transient voltage spikes or other interference.

[0087] Continue to refer to Figure 9 In some embodiments, the conversion circuit 100 includes an AC / DC conversion module 110 and at least one set of transformer-rectifier modules 120, with the AC / DC conversion module 110 connected to each transformer-rectifier module 120.

[0088] The transformer-rectifier module 120 includes a first transformer T1, a second transformer T2, a first rectifier unit, and a second rectifier unit. The primary end of the first transformer T1 is connected to the AC / DC conversion module 110, and the secondary end of the first transformer T1 is connected to the first rectifier unit. The primary end of the second transformer T2 is connected to the AC / DC conversion module 110, and the secondary end of the second transformer T2 is connected to the second rectifier unit. The first output terminal of the first rectifier unit serves as the first terminal S1 of the DC output terminal, and the second output terminal of the first rectifier unit serves as the second terminal S2 of the DC output terminal. The first output terminal of the second rectifier unit serves as the third terminal S3 of the DC output terminal, and the second output terminal of the second rectifier unit serves as the fourth terminal S4 of the DC output terminal.

[0089] In this embodiment, the AC / DC conversion module 110 is the front-end PFC (Power Factor Correction) section described in the previous embodiment. The AC / DC conversion module 110 is used to convert the input three-phase (i.e., Figure 8 The mains power (phases A, B, and C) is rectified into DC power and output to the subsequent DC / DC converter circuit 100.

[0090] The transformer-rectifier module 120 (i.e., the first transformer T1, the second transformer T2, the first rectifier unit, and the second rectifier unit) described in this embodiment is the downstream DC / DC converter circuit 100 described in the previous embodiment, and the first rectifier unit and the second rectifier unit are rectifier bridges.

[0091] Specifically, the conversion circuit 100 may include multiple sets of transformer-rectifier modules 120, each set of transformer-rectifier modules 120 being connected to the AC / DC conversion module 110, and the output of each set of transformer-rectifier modules 120 being a set of DC output terminals in the aforementioned embodiment.

[0092] Continue to refer to Figure 9 Taking a transformer-rectifier module 120 as an example, in some embodiments, the first rectifier unit includes a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6. The anode of the third diode D3 is connected to the cathode of the fourth diode D4 to serve as one input terminal of the first rectifier unit. The anode of the fifth diode D5 is connected to the cathode of the sixth diode D6 to serve as another input terminal of the first rectifier unit. The cathode of the third diode D3 is connected to the cathode of the fifth diode D5 to serve as the first output terminal of the first rectifier unit. The anode of the fourth diode D4 is connected to the anode of the sixth diode D6 to serve as the second output terminal of the first rectifier unit.

[0093] The second rectifier unit includes a seventh diode D7, an eighth diode D8, a ninth diode D9, and a tenth diode D10. The anode of the seventh diode D7 is connected to the cathode of the eighth diode D8 to serve as one input terminal of the second rectifier unit. The anode of the ninth diode D9 is connected to the cathode of the tenth diode D10 to serve as the other input terminal of the second rectifier unit. The cathode of the seventh diode D7 is connected to the cathode of the ninth diode D9 to serve as the first output terminal of the second rectifier unit. The anode of the eighth diode D8 is connected to the anode of the tenth diode D10 to serve as the second output terminal of the second rectifier unit.

[0094] Furthermore, one end of the secondary winding of the first transformer T1 is connected between the third diode D3 and the fourth diode D4, and the other end of the secondary winding of the first transformer T1 is connected between the fifth diode D5 and the sixth diode D6. One end of the secondary winding of the second transformer T2 is connected between the seventh diode D7 and the eighth diode D8, and the other end of the secondary winding of the second transformer T2 is connected between the ninth diode D9 and the tenth diode D10.

[0095] Continue to refer to Figure 9 In some embodiments, the module output circuit 300 may include a reverse protection diode DX and at least one output unit, each output unit being connected to an absorption protection circuit 200. The cathode of the reverse protection diode DX is connected to the positive terminal of the load. The reverse protection diode DX primarily serves to prevent reverse current flow.

[0096] The first input terminal M1 of any output unit is connected to the first terminal S1 of the corresponding DC output terminal, the second input terminal M2 is connected to the fourth terminal S4 of the corresponding DC output terminal, the third input terminal M3 is connected to the third connection terminal of the third switch unit 230 in the corresponding absorption protection circuit 200, the first output terminal is connected to the anode of the anti-reverse diode DX, and the second output terminal is connected to the negative terminal of the load.

[0097] Specifically, the output unit mainly consists of an output-side electrolytic capacitor and an output Y capacitor. Taking the first group of output units as an example, the output unit may include a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8. The fifth capacitor C5 is connected in parallel between the first input terminal M1 and the third input terminal M3 of the output unit. The sixth capacitor C6 is connected in parallel between the second input terminal M2 and the third input terminal M3 of the output unit. The seventh capacitor C7 and the eighth capacitor C8 are connected in series and then in parallel between the first input terminal M1 and the second input terminal M2 of the output unit, and the seventh capacitor C7 and the eighth capacitor C8 are grounded.

[0098] It should be noted that the fifth capacitor C5 and the sixth capacitor C6 can be electrolytic capacitors, and the seventh capacitor C7 and the eighth capacitor C8 can be output Y capacitors.

[0099] It is worth mentioning that the electrolytic capacitors (i.e., the fifth capacitor C5 and the sixth capacitor C6) of the charging module in this embodiment are located after the output-side relays (i.e., the first switching unit 210 and the second switching unit 220). Therefore, the loop design on the DC side is convenient and simple, and there is no need to design complex software code.

[0100] Therefore, by setting up an absorption protection circuit 200 in the charging module, especially configuring the first protection unit 240 and the second protection unit 250 composed of diodes, film capacitors and current-limiting resistors, a path is provided for the high-voltage pulse to flow through, which plays an auxiliary role in absorbing the voltage spikes applied to the rectifier bridge, thereby preventing the rectifier diodes from being damaged due to high voltage, ensuring the safe operation of the rectifier bridge in the subsequent DC conversion circuit 100, and improving the reliability of the charging module.

[0101] Based on the above embodiments, this application also provides a charging system, which may include multiple charging modules as described above.

[0102] It should be noted that for details not disclosed in the charging system of this embodiment, please refer to the details disclosed in the embodiments of the charging module in this specification, which will not be repeated here.

[0103] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A charging module, characterized in that, It includes a conversion circuit, at least one absorption protection circuit, and a module output circuit; The conversion circuit is connected to the module output circuit. The conversion circuit includes at least one set of DC output terminals. Each set of DC output terminals includes a first terminal, a second terminal, a third terminal, and a fourth terminal. Each absorption protection circuit is connected to one of the DC output terminals respectively. The absorption protection circuit includes a first switching unit, a second switching unit, a third switching unit, a first protection unit, and a second protection unit. The first protection unit includes a first diode and / or a first capacitor, and the second protection unit includes a second diode and / or a second capacitor. The first switch unit is connected in parallel between the first and third terminals of the DC output terminal, the second switch unit is connected in parallel between the second and fourth terminals of the DC output terminal, the first connection terminal of the third switch unit is connected to the second terminal and then grounded, the second connection terminal of the third switch unit is connected to the third terminal and then grounded, the first protection unit is connected in parallel between the two ends of the first switch unit, and the second protection unit is connected in parallel between the two ends of the second switch unit.

2. The charging module according to claim 1, characterized in that, The first protection unit includes a first diode and a first capacitor. The first diode is connected in parallel across the two ends of the first switching unit, and the first capacitor is connected in parallel across the two ends of the first diode. The second protection unit includes a second diode and a second capacitor. The second diode is connected in parallel across the two ends of the second switching unit, and the second capacitor is connected in parallel across the two ends of the second diode.

3. The charging module according to claim 1, characterized in that, The third switching unit includes a third relay and a fourth relay; One end of the third relay is connected to the second end of the DC output terminal, and the other end of the third relay is connected to the module output circuit; One end of the fourth relay is connected to the third end of the DC output terminal, and the other end of the fourth relay is connected to the module output circuit.

4. The charging module according to claim 1, characterized in that, The third switching unit includes a third relay. One end of the third relay is connected to the second end of the DC output terminal and then connected to the module output circuit. The other end of the third relay is connected to the third end of the DC output terminal and then connected to the module output circuit.

5. The charging module according to any one of claims 1-4, characterized in that, The absorption protection circuit also includes a first resistor and a second resistor; The first resistor is connected in series between the first switching unit and the first protection unit; The second resistor is connected in series between the second switching unit and the second protection unit.

6. The charging module according to any one of claims 1-4, characterized in that, The absorption protection circuit also includes a third capacitor and a fourth capacitor; The third capacitor is connected in parallel between the first and second terminals of the DC output. The fourth capacitor is connected in parallel between the third and fourth terminals of the DC output.

7. The charging module according to any one of claims 1-4, characterized in that, The conversion circuit includes an AC / DC conversion module and at least one set of transformer-rectifier modules, wherein the AC / DC conversion module is connected to each of the transformer-rectifier modules. The transformer-rectifier module includes a first transformer, a second transformer, a first rectifier unit, and a second rectifier unit; The primary terminal of the first transformer is connected to the AC / DC conversion module, and the secondary terminal of the first transformer is connected to the first rectifier unit. The primary terminal of the second transformer is connected to the AC / DC conversion module, and the secondary terminal of the second transformer is connected to the second rectifier unit. The first output terminal of the first rectifier unit serves as the first terminal of the DC output terminal, and the second output terminal of the first rectifier unit serves as the second terminal of the DC output terminal. The first output terminal of the second rectifier unit serves as the third terminal of the DC output terminal, and the second output terminal of the second rectifier unit serves as the fourth terminal of the DC output terminal.

8. The charging module according to claim 7, characterized in that, The first rectifier unit includes a third diode, a fourth diode, a fifth diode, and a sixth diode; The anode of the third diode is connected to the cathode of the fourth diode and serves as one input terminal of the first rectifier unit. The anode of the fifth diode is connected to the cathode of the sixth diode and serves as another input terminal of the first rectifier unit. The cathode of the third diode is connected to the cathode of the fifth diode and serves as the first output terminal of the first rectifier unit. The anode of the fourth diode is connected to the anode of the sixth diode and serves as the second output terminal of the first rectifier unit. The second rectifier unit includes a seventh diode, an eighth diode, a ninth diode, and a tenth diode; The anode of the seventh diode is connected to the cathode of the eighth diode and serves as one input terminal of the second rectifier unit. The anode of the ninth diode is connected to the cathode of the tenth diode and serves as another input terminal of the second rectifier unit. The cathode of the seventh diode is connected to the cathode of the ninth diode and serves as the first output terminal of the second rectifier unit. The anode of the eighth diode is connected to the anode of the tenth diode and serves as the second output terminal of the second rectifier unit.

9. The charging module according to any one of claims 1-4, characterized in that, The module output circuit includes an anti-reverse diode and at least one output unit, and each output unit is connected to an absorption protection circuit. The first input terminal of any of the output units is connected to the first terminal of the corresponding DC output terminal, the second input terminal is connected to the fourth terminal of the corresponding DC output terminal, the third input terminal is connected to the third connection terminal of the third switching unit in the absorption protection circuit, the first output terminal is connected to the anode of the anti-reverse diode, and the second output terminal is connected to the negative terminal of the load. The cathode of the anti-reverse diode is connected to the positive terminal of the load.

10. A charging system, characterized in that, It includes at least one charging module as described in any one of claims 1-9.

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