Precharge circuit

Abstract

The application provides a pre-charging circuit. The pre-charging circuit comprises a first load, at least one second load, and a short circuit module corresponding to the second load; the first load and the at least one second load are connected in series and connected between a power supply and an energy storage module; the first end of the short circuit module is connected to one end of the corresponding second load, and the second end is connected to the other end of the corresponding second load, for short-circuiting the one end and the other end of the second load. According to the scheme, the first load and the second load can reduce the large current impact in the initial pre-charging stage; when the voltage of the energy storage module reaches a preset threshold, the short circuit module short-circuits the corresponding second load, reduces the total impedance of the circuit and the pre-charging time constant, and thus improves the pre-charging efficiency.

Description

Technical Field

[0001] This application relates to electronic power technology, and more particularly to a pre-charging circuit. Background Technology

[0002] When starting up an energy storage converter, it is necessary to precharge the connected high-voltage electrical equipment, such as transformers and capacitors. This is because these devices typically contain large-capacity DC support capacitors. If directly connected to a high-voltage power source, the huge voltage difference will instantly generate a dangerous surge current, which can easily damage power devices, fuses, or even the equipment itself.

[0003] In the relevant pre-charge circuit, in order to achieve sufficient energy buffering and support voltage, a support capacitor with a relatively high capacitance value is usually set, which leads to an increase in the pre-charge time constant, lengthens the system pre-charge time and system power-on time, and reduces the efficiency of pre-charge. Utility Model Content

[0004] This application provides a pre-charging circuit to improve the efficiency of pre-charging.

[0005] On one hand, this application provides a pre-charging circuit, including: a first load, at least one second load, and a short-circuit module corresponding to each second load; the first load and at least one second load are connected in series and connected between a power supply and an energy storage module; a first end of the short-circuit module is connected to one end of the corresponding second load, and a second end is connected to the other end of the corresponding second load, for short-circuiting one end and the other end of the second load.

[0006] In one possible implementation, the circuit further includes: a first switch; the first switch is connected in series with a first load and at least one second load.

[0007] In one possible implementation, the circuit further includes a second switch; the second switch is connected between the power supply and the energy storage module, and the second switch is not in the same current loop as the first switch.

[0008] In one possible implementation, the short-circuit module includes a first resistor, a second resistor, and a first switching transistor; one end of the first resistor, the first end of the first switching transistor, and one end of the corresponding second load are connected to a first connection point; the other end of the first resistor, the control terminal of the first switch, and one end of the second resistor are connected to a second connection point; the second end of the first switching transistor is connected to the other end of the corresponding second load; the other end of the second resistor is connected to a power supply and an energy storage module, and one end and the other end of the second resistor are connected to different sides of the power supply.

[0009] In one possible implementation, the short-circuit module further includes a second switching transistor; the first end of the second switching transistor is connected to the other end of the second resistor, and the second end is connected to the power supply and energy storage module.

[0010] In one possible implementation, the short-circuit module further includes a voltage regulator unit; the negative terminal of the voltage regulator unit is connected to the first connection point, and the positive terminal is connected to the second connection point.

[0011] In one possible implementation, the short-circuit module is a low-power relay.

[0012] In one possible implementation, the resistance of the first load is less than the resistance of the second load.

[0013] In one possible implementation, the pre-charging circuit is located on the positive side circuit of the power supply and energy storage module.

[0014] In one possible implementation, the pre-charging circuit is located on the negative side circuit of the power supply and energy storage module.

[0015] The pre-charging circuit provided in this application includes a first load, at least one second load, and a short-circuit module corresponding to each second load. The first load and at least one second load are connected in series and connected between the power supply and the energy storage module. The first end of the short-circuit module is connected to one end of the corresponding second load, and the second end is connected to the other end of the corresponding second load, for short-circuiting the connection between one end and the other end of the second load. In this application's solution, the first and second loads can reduce large current surges during the initial pre-charging stage. When the voltage of the energy storage module reaches a preset threshold, the short-circuit module short-circuits the corresponding second load, reducing the total impedance of the circuit and the pre-charging time constant, thereby improving the pre-charging efficiency. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] Figure 1 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application;

[0018] Figure 2 This is a graph showing the change in pre-charge current and voltage curves provided in an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application.

[0022] Explanation of reference numerals in the attached drawings: First load 10; Second load 20; Short circuit module 30; First switch 40; Second switch 50; First resistor 31; Second resistor 32; First switching transistor 33; Voltage regulator unit 34; Second switching transistor 35.

[0023] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0025] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning. In addition, the terms "comprising" and "having," and any variations thereof, are intended to be omnipresent but not exclusive. For example, a product or device that comprises a series of components is not necessarily limited to those components that are explicitly listed, but may include other components that are not explicitly listed or that are inherent to such product or device.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0028] In energy storage converters, pre-charging the load devices connected to the high-voltage DC bus (or other high-voltage ports), such as transformers and filter capacitors, before startup is an essential and critical step. This is because these load devices typically contain large-capacity DC bus support capacitors or equivalent capacitive loads. At the initial connection moment, it is equivalent to instantaneously connecting the capacitor to a high-voltage source. Without restraint, the huge voltage difference can trigger an extremely dangerous inrush current. This inrush current can instantly reach kiloamperes far exceeding the equipment's withstand capacity, directly damaging the converter's power switching devices, blowing high-voltage fuses, and causing equipment failure and shutdown; in severe cases, it may also damage the load devices themselves, such as breaking down capacitors, generating electric arcs, and even creating safety hazards.

[0029] In related technologies, energy storage converters typically incorporate a pre-charging circuit, usually consisting of a pre-charging contactor, a series current-limiting resistor, and corresponding control logic. Before startup or grid connection, the main power contactor is first disconnected, and the pre-charging contactor circuit is closed, allowing the high-voltage power supply to gradually charge the capacitive load slowly and in a controlled manner through the current-limiting resistor. During this period, the current is effectively limited within a safe range by the resistor. When the bus voltage or other key parameters reach a preset threshold, such as approaching 90% of the source voltage, it indicates that the pre-charging process is complete and the system voltage has essentially reached equilibrium. At this point, the control system disconnects the pre-charging circuit and closes the main contactor or starts the power device, allowing the converter to fully connect to the high-voltage system and enter normal operating mode.

[0030] However, in the pre-charge circuits of related technologies, the capacitance of the supporting capacitor or equivalent capacitive element within the system is often designed to be very large in order to achieve sufficient energy buffering, filtering, or voltage stabilization. In the pre-charge loop, the pre-charge time constant is mainly determined by the product of the current-limiting resistor and the total capacitance of the capacitive load. Since the total capacitance must be large enough to meet the normal operating requirements of the system, this directly leads to a significant increase in the time constant of the pre-charge loop. In other words, the huge capacitive load directly prolongs the necessary pre-charge process, thereby increasing the total time required for the system to complete power-on from startup. Therefore, the current problem to be solved is how to improve the efficiency of pre-charge.

[0031] To address the aforementioned technical problems, this application provides a pre-charging circuit, including a first load, at least one second load, and a short-circuit module corresponding to each second load. The first load and at least one second load are connected in series and connected between the power supply and the energy storage module. A first end of the short-circuit module is connected to one end of the corresponding second load, and a second end is connected to the other end of the corresponding second load, for short-circuiting the connection between one end and the other end of the second load. In this solution, the first and second loads can reduce large current surges during the initial pre-charging phase. When the voltage of the energy storage module reaches a preset threshold, the short-circuit module short-circuits the corresponding second load, reducing the total impedance of the circuit and the pre-charging time constant, thereby improving the pre-charging efficiency.

[0032] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application. Figure 1 As shown, the pre-charging circuit includes:

[0034] A first load 10, at least one second load 20, and a short-circuit module 30 corresponding to each second load 20;

[0035] The first load 10 is connected in series with at least one second load 20 and is connected between the power supply and the energy storage module;

[0036] The first end of the short-circuit module 30 is connected to one end of the corresponding second load 20, and the second end is connected to the other end of the corresponding second load 20, for short-circuiting the connection between one end and the other end of the second load 20.

[0037] For example, the first load 10 can be a pre-charge resistor used to limit inrush current. In practical applications, its model can be determined based on current, temperature rise, and power calculations. Specifically, the first load 10 can be a single pre-charge resistor or a combination of multiple pre-charge resistors. Optionally, the first load 10 can also be a circuit or module with load functionality.

[0038] In some alternative implementations, the first load 10 may also be a fusible resistor, which combines current limiting and overcurrent protection functions, and improves safety by fusing during abnormally high currents.

[0039] For example, in practical applications, the second load 20 can be implemented with reference to the first load 10. For instance, the model and load resistance value of the second load 20 can be the same as or different from those of the first load 10, and this application does not limit this.

[0040] In some implementations, the short-circuit module 30 may be a switching device such as an electromagnetic contactor, a relay, or a semiconductor switch, connected between one end and the other end of the second load 20, providing a low-impedance path to bypass the second load 20 when closed.

[0041] For example, the energy storage module can be the front-end capacitor of a circuit such as a DC / DC converter or inverter, i.e., the supporting capacitor of the DC bus. For instance, it can be the front-end capacitor of an inverter in an uninterruptible power supply system, the front-end capacitor of an inverter in a photovoltaic or wind power grid-connected system, or the front-end capacitor of a motor controller in an electric vehicle. Optionally, the energy storage module can also be a capacitor module, a battery pack, or a battery array.

[0042] In some implementations, the number of second loads 20 can be one. During the initial pre-charge phase, the potential difference between the power supply and the energy storage module is large, resulting in a large current in the corresponding circuit. By connecting the first load 10 and the second load 20 in series in the pre-charge circuit, the short-circuit module 30 corresponding to the second load 20 is deactivated. A larger pre-charge resistance value can reduce the inrush current. Specifically, when the resistance of the first load 10 is R1, the resistance of the second load 20 is R2, and the capacitance of the energy storage module is C, the pre-charge time constant is (R1 + R2) * C.

[0043] Furthermore, when the voltage of the energy storage module reaches the preset value Vn, the short-circuit module 30 corresponding to the second load 20 is controlled to operate, short-circuiting one end of the second load 20 and the other end. At this time, the pre-charging time constant is reduced to R1 * C, thereby accelerating the pre-charging process by reducing the pre-charging resistance value. Although the pre-charging resistance value is reduced, the potential difference between the power supply and the energy storage module decreases as the energy storage module voltage rises, thus preventing excessive inrush current. When the power supply voltage is Vdc, the inrush current when the short-circuit module 30 operates is (Vdc-Vn) / R1. When the voltage across the energy storage module rises to the preset value Vd, if it is any value between 90% and 95% of the power supply voltage, the pre-charging process ends. In practical applications, Vn depends on the sampling accuracy of the energy storage module voltage and can be set to (Vdc-Vn) / R1 as the safe inrush current that the circuit can withstand; Vd depends on the sampling accuracy of the energy storage module voltage and can be set to (Vdc-Vd) / R1 as the safe inrush current that the circuit can withstand.

[0044] Figure 2 This is a graph showing the change in pre-charge current and voltage as provided in an embodiment of this application. Figure 2 As shown, as the voltage Vbus of the energy storage module gradually increases, the current Ipc of the pre-charging circuit gradually decreases. At time T1, when the voltage of the energy storage module reaches the preset value Vn, the short-circuit module 30 corresponding to the second load 20 works, and the rate of change of the charging voltage reaches Vd at time T2. Compared with keeping the first load 10 and the second load 20 connected in series in the pre-charging circuit, the time T3-T2 can be reduced.

[0045] In some optional implementations, the number of second loads 20 can be greater than one to achieve phased acceleration of charging during the pre-charging process. For example, multiple second loads 20 can be set, each connected to a corresponding short-circuit module 30 at both ends, and the preset values ​​Vn corresponding to the multiple second loads 20 gradually increase or decrease. For instance, there are three second loads 20, A, B, and C, with corresponding preset values ​​V1, V2, and V3. In the initial charging stage, A, B, and C are all connected in series in the pre-charging circuit. When the voltage of the energy storage module reaches V1, the short-circuit module 30 corresponding to A operates to reduce the pre-charging resistance value; when the voltage of the energy storage module reaches V2, the short-circuit module 30 corresponding to B operates to further reduce the pre-charging resistance value; when the voltage of the energy storage module reaches V3, the short-circuit module 30 corresponding to C operates to further reduce the pre-charging resistance value, until the voltage of the energy storage module reaches Vd. This example scheme, by gradually reducing the pre-charging time constant in stages, can limit the impact circuit within a safe range while further accelerating the pre-charging process.

[0046] The pre-charging circuit provided in this application includes a first load, at least one second load, and a short-circuit module corresponding to each second load. The first load and at least one second load are connected in series and connected between the power supply and the energy storage module. The first end of the short-circuit module is connected to one end of the corresponding second load, and the second end is connected to the other end of the corresponding second load, for short-circuiting the connection between one end and the other end of the second load. In this application's solution, the first and second loads can reduce large current surges during the initial pre-charging stage. When the voltage of the energy storage module reaches a preset threshold, the short-circuit module short-circuits the corresponding second load, reducing the total impedance of the circuit and the pre-charging time constant, thereby improving the pre-charging efficiency.

[0047] As yet another example, based on any example, the short-circuit module 30 is a low-power relay.

[0048] In practical applications, when the voltage of the energy storage module reaches the preset value Vn, the current in the circuit is relatively small, so low-power devices can be selected to reduce the hardware cost of the circuit.

[0049] For example, the relay may include a control coil and a power contact, the power contact being used to connect one end and the other end of the corresponding second load 20. Specifically, the voltage across the energy storage module can be acquired by a voltage acquisition module, and the control coil can be energized by a main control chip such as a digital signal processor or microcontroller when conditions are met, thereby turning on the power contact.

[0050] The solution in this example, based on low-power relay control, reduces control voltage drop and power consumption, and lowers circuit cost.

[0051] As yet another example, based on any example, the resistance of the first load 10 is less than the resistance of the second load 20.

[0052] For example, the resistance of the first load 10 can be set to be less than the resistance of a single second load 20; when there are multiple second loads 20, the resistance of the first load 10 can also be set to be greater than the resistance of a single second load 20, but less than the total resistance of all second loads 20, thereby reducing the inrush current while reducing the precharge time.

[0053] The solution in this example, by setting the resistance value of the first load 10 to be less than the resistance value of the second load 20, can reduce the resistance value of the pre-charging resistor in the circuit when the voltage difference between the power supply and the energy storage module is small, thereby improving the pre-charging efficiency.

[0054] Figure 3 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application. Figure 3As shown, the circuit also includes: a first switch 40; the first switch 40 is connected in series with a first load 10 and at least one second load 20.

[0055] For example, the first switch 40 can be a relay, used to turn on when the system needs pre-charging to allow the power supply to deliver current to the energy storage module, and to turn off when pre-charging needs to be stopped. In practical applications, a high-power relay can be selected to allow for the normal passage of large currents during the initial stage of pre-charging, thus reducing device aging.

[0056] Alternatively, the circuit cost can be reduced by increasing the resistance of the first load 10 and selecting the first switch 40 of a low-power relay.

[0057] In this example, the controllability of the pre-charging circuit can be improved by using the first switch 40.

[0058] Figure 3 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application. Figure 3 As shown, based on any example, the circuit further includes: a second switch 50;

[0059] The second switch 50 is connected between the power supply and the energy storage module, and the second switch 50 and the first switch 40 are not in the same current loop.

[0060] In practical applications, the second switch 50 can directly reuse the relay of the DC bus.

[0061] In this example, when the voltage across the energy storage module rises to a preset value Vd, such as 90% to 95% of the power supply voltage, the pre-charging process ends and the power supply is directly powered by closing the second switch 50 to short-circuit the circuit of the first load 10, the second load 20, and the first switch 40.

[0062] Figure 4 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application. Figure 4 As shown, the short-circuit module 30 includes a first resistor 31, a second resistor 32, and a first switching transistor 33;

[0063] One end of the first resistor 31, the first end of the first switch 33, and one end of the corresponding second load 20 are all connected to the first connection point;

[0064] The other end of the first resistor 31, the control terminal of the first switch 40, and one end of the second resistor 32 are all connected to the second connection point.

[0065] The second end of the first switching transistor 33 is connected to the other end of the corresponding second load 20;

[0066] The other end of the second resistor 32 is connected to the power supply and energy storage module, and one end of the second resistor 32 and the other end are connected to different sides of the power supply.

[0067] For example, the first terminal of the first switch 33 is the output terminal, which can be the drain of a metal-oxide-semiconductor field-effect transistor (MOSFET) or the collector of an insulated-gate bipolar transistor (IGBT); the second terminal of the first switch 33 is the input terminal, which can be the source of a metal-oxide-semiconductor field-effect transistor or the emitter of an insulated-gate bipolar transistor.

[0068] In this example, the first resistor 31 is connected in series in the control circuit of the first switch 33 to limit the control terminal current, such as the gate charging current of the MOSFET, reduce the breakdown of the switch caused by control signal overshoot, and reduce the oscillation caused by rapid charging and discharging of the gate capacitor in the MOSFET.

[0069] For example, when one end of the second resistor 32 is connected to the positive terminal of the power supply through the second connection point, the other end of the second resistor 32 is connected to the negative terminal of the power supply and energy storage module; when one end of the second resistor 32 is connected to the negative terminal of the power supply through the second connection point, the other end of the second resistor 32 is connected to the positive terminal of the power supply and energy storage module.

[0070] In some embodiments, the second resistor 32 is connected between the negative terminal of the power supply and the second connection point to form a voltage divider detection network to monitor the voltage rise process of the energy storage module: when the voltage rises, the voltage of the second connection point rises accordingly; when the voltage of the second connection point exceeds the conduction threshold of the first switch 33, the first switch 33 is turned on to achieve a short circuit between one end and the other end of the second load 20.

[0071] In practical applications, the resistance ratio of the first resistor 31 and the second resistor 32 can be set, and the resistance value of the second resistor 32 determines the conduction trigger voltage threshold. For example, if triggering is required when the power supply voltage reaches 90%, the second resistor value / (first resistor value + second resistor value) ≈ 0.9 is calculated based on the voltage division ratio.

[0072] In some optional examples, the short-circuit module 30 also includes a voltage regulator unit 34;

[0073] The negative terminal of the voltage regulator unit 34 is connected to the first connection point, and the positive terminal is connected to the second connection point.

[0074] This optional example uses the voltage regulator unit 34 to clamp the voltage difference between the first connection point and the second connection point, thereby reducing voltage spikes and oscillations during the operation of the first switch 33, improving the stability of the control signal, reducing false triggering of the first switch 33, and enhancing system reliability.

[0075] In the scheme of this application, the voltage across the first resistor 31 is used as the driving voltage of the first switch 33 in the constructed voltage divider circuit. By adjusting the resistance ratio of the first resistor 31 and the second resistor 32, the second load 20 can be automatically short-circuited when the pre-charging condition is met, which improves the response speed of the short-circuit module 30 and reduces the possibility of abnormal arcing when connected only by a relay.

[0076] Figure 5 This is a schematic diagram of the pre-charging circuit provided in an embodiment of this application. Figure 5 As shown, the short-circuit module 30 also includes a second switching transistor 35;

[0077] The first end of the second switch 35 is connected to the other end of the second resistor 32, and the second end is connected to the power supply and energy storage module.

[0078] In this example, in addition to ensuring that the voltage across the energy storage module satisfies the short-circuit module 30 for conduction, the second switch 35 also needs to be turned on in order for the first switch 33 to meet the conduction conditions.

[0079] In practical applications, the control terminal of the second switch 35 can be connected to a microcontroller or a digital signal processor. In some embodiments, the turn-on timing of the second switch 35 can be dynamically adjusted in conjunction with parameters such as temperature and battery aging status. Optionally, the second switch 35 can also be turned off when the first switch 33 breaks down or the second resistor 32 is open, in order to achieve fault isolation and improve the robustness of the circuit.

[0080] In some optional examples, the short-circuit module 30 also includes a voltage regulator unit 34;

[0081] The negative terminal of the voltage regulator unit 34 is connected to the first connection point, and the positive terminal is connected to the second connection point.

[0082] This optional example uses the voltage regulator unit 34 to clamp the voltage difference between the first connection point and the second connection point, thereby reducing voltage spikes and oscillations during the operation of the first switch 33, improving the stability of the control signal, reducing false triggering of the first switch 33, and enhancing system reliability.

[0083] The solution in this example, by adding a second switch 35, can avoid the short-circuit module 30 from being mis-activated due to voltage surges, thereby preventing the high inrush current caused by the surge in the pre-charge circuit current and improving the safety of the circuit; on the other hand, it can also reduce the static current across the second resistor 32 and reduce static power consumption.

[0084] As yet another example, based on any example, the pre-charge circuit is set in the positive side loop of the power supply and energy storage module.

[0085] The solution in this example sets the pre-charging circuit in the positive side loop of the power supply and energy storage module. Based on the high potential control of the positive side, it can avoid noise interference from the ground loop. At the same time, cutting off the positive power supply path can directly prevent energy transfer and enhance the redundancy of system-level short-circuit protection.

[0086] As yet another example, based on any example, the pre-charge circuit is set in the negative side loop of the power supply and energy storage module.

[0087] The solution in this example, by placing the pre-charge circuit on the negative side of the power supply and energy storage module, can move the heat source of the pre-charge resistors, such as the first load 10 and the second load 20, to the low-voltage side. This not only reduces common-mode noise but also avoids the high temperature of the resistors affecting the sensitive control chip.

[0088] The pre-charging circuit provided in this application includes a first load, at least one second load, and a short-circuit module 30 corresponding to each second load. The first load and at least one second load are connected in series and connected between the power supply and the energy storage module. The first end of the short-circuit module 30 is connected to one end of the corresponding second load, and the second end is connected to the other end of the corresponding second load, for short-circuiting one end and the other end of the second load. In this application's solution, the first and second loads can reduce large current surges during the initial pre-charging stage. When the voltage of the energy storage module reaches a preset threshold, the short-circuit module short-circuits the corresponding second load, reducing the total impedance of the circuit and the pre-charging time constant, thereby improving the pre-charging efficiency.

[0089] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0090] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A pre-charge circuit, characterized by, include: A first load, at least one second load, and a short-circuit module corresponding to each second load; The first load is connected in series with the at least one second load and is connected between the power supply and the energy storage module; The first end of the short-circuit module is connected to one end of the corresponding second load, and the second end is connected to the other end of the corresponding second load, for short-circuiting the connection between one end and the other end of the second load.

2. The circuit of claim 1, wherein, The circuit also includes: a first switch; The first switch is connected in series with the first load and the at least one second load.

3. The circuit of claim 2, wherein, The circuit also includes: a second switch; The second switch is connected between the power source and the energy storage module, and the second switch and the first switch are not in the same current loop.

4. The circuit of claim 1, wherein, The short-circuit module includes a first resistor, a second resistor, and a first switching transistor; One end of the first resistor, the first end of the first switching transistor, and one end of the corresponding second load are all connected to the first connection point. The other end of the first resistor, the control terminal of the first switch, and one end of the second resistor are all connected to the second connection point. The second end of the first switching transistor is connected to the other end of the corresponding second load. The other end of the second resistor is connected to the power supply and energy storage module, and one end and the other end of the second resistor are connected to different sides of the power supply.

5. The circuit of claim 4, wherein, The short-circuit module also includes a second switching transistor; The first end of the second switching transistor is connected to the other end of the second resistor, and the second end is connected to the power supply and energy storage module.

6. The circuit of claim 4 or 5, characterized in that, The short-circuit module also includes a voltage regulator unit; The negative terminal of the voltage regulator unit is connected to the first connection point, and the positive terminal is connected to the second connection point.

7. The circuit of claim 1, wherein, The short-circuit module is a low-power relay.

8. The circuit of claim 1, wherein, The resistance of the first load is less than the resistance of the second load.

9. The circuit according to any of claims 1-8, characterized in that, The pre-charging circuit is located on the positive side circuit of the power supply and energy storage module.

10. The circuit of any one of claims 1-8, wherein, The pre-charging circuit is located on the negative side circuit of the power supply and energy storage module.

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