Switch mode precharge circuit

Abstract

This switch mode control circuit comprises: a battery link configured to be connected to a battery; a capacitor link configured to be connected to a capacitor; and a precharge circuit connected in series between the battery link and the capacitor link and configured to limit an inrush current to the capacitor during initial power connection. The precharge circuit includes: a switching mechanism configured to switch between an open state and a closed state; a shunt resistor that monitors current; and a controller operably connected to the switching mechanism and configured to control a duty cycle of the switching mechanism. The controller dynamically adjusts the duty cycle of the switching mechanism by intermittently closing the switching mechanism until a certain voltage is reached, and when the certain voltage is reached, the controller maintains the switching mechanism in the closed state such that a continuous direct current flows from the battery to the capacitor.

Description

Switch mode precharge circuit

[0001] The present disclosure generally relates to the field of battery disconnect units, in particular to switch-mode precharge circuits.

[0002] This section provides background information related to the present disclosure and is not necessarily prior art.

[0003] In high-voltage electrical systems, such as electric vehicles, a large voltage difference between the load capacitor and the high-voltage battery can cause significant inrush current upon connection. This inrush current can damage power relays and other subsequent components. This issue is particularly critical in medium to large battery packs, such as those used in electric vehicles, where sudden surges in current can lead to fusion or other forms of relay damage.

[0004] To mitigate the effects of inrush current, conventional systems often use precharge relays and precharge resistors connected in parallel with the main power relay. In electric vehicles, the precharge relay and precharge resistor initially deliver power to the motor, allowing the current to stabilize before the main relay fully connects the battery to the motor. While this method can prevent damage to the power relay, if the inrush current exceeds the rated power of the precharge resistor, micro-damage or micro-welding may occur, potentially increasing the resistor's resistance over time.

[0005] The present invention solves this problem by introducing a switch mode control circuit for limiting inrush current.

[0006] This section provides a general summary of the content of the disclosure and does not comprehensively disclose the full scope or all features. Each example disclosed herein may include one or more of the features described in relation to other examples disclosed herein.

[0007] The present disclosure provides a switch mode control circuit comprising: a battery link configured to be connected to a battery for supplying power; a capacitor link configured to be connected to a capacitor for receiving power from said battery; and a precharge circuit connected in series between said battery link and said capacitor link and configured to limit an inrush current to said capacitor during initial power connection. The precharge circuit comprises a switching mechanism configured to switch between an open state and a closed state; a shunt resistor for monitoring current; and a controller operably connected to said switching mechanism and configured to control the duty cycle of said switching mechanism. The controller dynamically adjusts the duty cycle of said switching mechanism to switch from an open state to a closed state by intermittently closing the switching mechanism during a stabilization period until a predetermined voltage is reached, and when said predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a continuous direct current flows from said battery to said capacitor.

[0008] According to one aspect of the present disclosure, it is connected to the negative terminal of the battery link.

[0009] According to another aspect of the present disclosure, the controller dynamically adjusts the duty cycle using pulse width modulation.

[0010] According to another aspect of the present disclosure, dynamically adjusting the duty cycle includes changing the frequency of the pulse width modulation.

[0011] According to another aspect of the present disclosure, the controller dynamically adjusts the duty cycle in real time based on the current of the capacitor link, the output voltage of the capacitor link, and the current measured at the negative terminal of the battery through the precharge circuit.

[0012] According to another aspect of the present disclosure, the switching mechanism is one or more MOSFETs or other solid-state switches.

[0013] According to another aspect of the present disclosure, the precharge circuit is configured to monitor at least one of an open circuit, an overload, and a short circuit.

[0014] According to another aspect of the present disclosure, the predetermined voltage is about 0 V.

[0015] According to another aspect of the present disclosure, when the predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a continuous direct current flows from the battery to the capacitor until the capacitor is fully charged.

[0016] According to another aspect of the present disclosure, a switch mode control system comprises a battery configured to supply power, a capacitor configured to receive power from the battery, and a precharge circuit connected in series between the battery and the capacitor and configured to limit the current flowing into the capacitor upon initial connection of the battery. The precharge circuit comprises a switching mechanism configured to switch between an open state and a closed state, and a controller operably connected to the switching mechanism and configured to control the duty cycle of the switching mechanism. The controller dynamically adjusts the duty cycle of the switching mechanism to switch from an open state to a closed state by intermittently closing the switching mechanism during a stabilization period until a predetermined voltage is reached, and when the predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a continuous direct current flows from the battery to the capacitor.

[0017] According to another aspect of the present disclosure, the precharge circuit is connected to the negative terminal of the battery.

[0018] According to another aspect of the present disclosure, the controller dynamically adjusts the duty cycle using pulse width modulation.

[0019] According to another aspect of the present disclosure, dynamically adjusting the duty cycle includes changing the frequency of the pulse width modulation.

[0020] According to another aspect of the present disclosure, the controller dynamically adjusts the duty cycle in real time based on the current of the capacitor, the output voltage of the capacitor, and the current measured at the negative terminal of the battery through the precharge circuit.

[0021] According to another aspect of the present disclosure, the switching mechanism is one or more MOSFETs or other solid-state switches.

[0022] According to another aspect of the present disclosure, the precharge circuit is configured to monitor at least one of an open circuit, an overload, and a short circuit.

[0023] According to another aspect of the present disclosure, the predetermined voltage is about 0 V.

[0024] According to another aspect of the present disclosure, when the predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a continuous direct current flows from the battery to the capacitor until the capacitor is fully charged.

[0025] According to another aspect of the present disclosure, a switch mode control circuit comprises a battery link (LINK+) configured to be connected to a battery for supplying power, a capacitor link (LINK-) configured to be connected to a capacitor for receiving power from the battery, and a precharge circuit connected in series between the battery link and the capacitor link and configured to limit an inrush current to the capacitor during initial power connection. The precharge circuit comprises a switching mechanism configured to switch between an open state and a closed state, a shunt resistor connected to a battery negative terminal (PACK-) to monitor current flow, and a controller operably connected to the switching mechanism and configured to control the duty cycle of the switching mechanism. The controller dynamically adjusts the duty cycle of the switching mechanism to switch from an open state to a closed state by intermittently closing the switching mechanism during a stabilization period until a predetermined voltage is reached, and once the predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a direct current flows continuously from the battery to the capacitor until the capacitor is fully charged.

[0026] According to another aspect of the present disclosure, the controller dynamically adjusts the duty cycle in real time based on the current of the capacitor link, the output voltage of the capacitor link, and the current measured at the negative terminal of the battery through the precharge circuit.

[0027] Additionally, the scope of applicability will become clear through the descriptions provided herein. The descriptions and specific examples in this summary are provided for illustrative purposes only and are not intended to limit the scope of the rights of this disclosure.

[0028] The drawings described herein are for exemplary purposes only of selected embodiments and are not intended to limit the scope of the rights of the present disclosure.

[0029] FIG. 1 is a block circuit diagram of an embodiment of a battery cutoff device including a switch mode precharge circuit;

[0030] Figure 2 is a circuit diagram of an example of a switch mode precharge circuit.

[0031] Figure 3 is a flowchart of an inrush current control process according to an embodiment of a switch mode precharge circuit.

[0032] Drawing symbols indicate corresponding parts in various views of the drawing.

[0033] The embodiments are described below in detail with reference to the attached drawings. Where possible, identical or similar drawing numbers are used throughout the drawings to denote identical or similar parts. The embodiments may solve one or more problems of the art. However, the scope of the disclosure is defined by the appended claims, not by the ability to solve specific problems.

[0034] Embodiments are provided so that the scope of the disclosure can be sufficiently conveyed to those skilled in the art. Numerous specific details, such as examples of specific components, devices, and methods, are presented to enable a sufficient understanding of the embodiments of the disclosure. However, it will be apparent to those skilled in the art that specific details are not necessary, that the embodiments may be implemented in various forms, and that none of these should be interpreted as limiting the scope of the disclosure. In some embodiments, well-known processors, device structures, and technologies will not be described in detail.

[0035] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit them. Singular expressions used herein may be interpreted to include the plural unless otherwise indicated in the context. The terms “include,” “compose,” and “have” specify the presence of the described features, integers, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof. The method steps, processes, and actions described herein should not be interpreted as necessarily being performed in the specific order described or illustrated unless specifically specified for execution, and additional or alternative steps may be used.

[0036] Where an element or layer is referred to as being "on top of," "interlocked," "connected," or "combined" with another element or layer, it may be directly on top of, directly interlocked, directly connected, or directly combined with the other element or layer, or an intermediate element or layer may exist. Conversely, where an element or layer is referred to as being "directly on top of," "directly interlocked," "directly connected," or "directly combined" with another element or layer, an intermediate element or layer may not exist. Other words used to describe relationships between elements (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.) are interpreted in a similar manner. The term "and / or" as used herein includes any combination of one or more of the listed items.

[0037] Terms such as first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or sections, but such elements, components, regions, layers, and / or sections are not limited by these terms. These terms may be used solely to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Terms including “first,” “second,” and other ordinal numbers used herein do not imply a sequence or order unless explicitly stated in the context. Accordingly, the first element, component, region, layer, or section described below may be referred to as the second element, component, region, layer, or section without departing from the disclosure of the embodiments.

[0038] Spatially relative terms such as "inside," "outside," "bottom," "below," "lower," "top," and "upper" may be used for convenience of explanation to describe the relationship between one element or feature and another as depicted in the drawings. Spatially relative terms may be intended to include directions of the device in use or operation other than those depicted in the drawings. For example, if the device is inverted in the drawings, an element described as "below" or "bottom" of another element or feature will face "top" of that element or feature. Thus, the exemplary term "below" may include both the up and down directions. The device may be positioned in different directions (rotated 90 degrees or other directions), and the spatially relative descriptions used herein may be interpreted accordingly.

[0039] In disclosures, relative terms such as "approximately," "substantially," "generally," and "roughly" are used to indicate a possibility of ±10% variation from the specified value or characteristic.

[0040] During the starting phase of an electric vehicle, the inrush current can damage high-voltage relays or contactors and subsequent components of a high-voltage power control system. A switch mode precharge circuit (20) according to the start content dynamically controls the flow of current through the precharge circuit (20) to prevent damage to the high-voltage relays and subsequent components of the high-voltage power control system.

[0041] FIG. 1 illustrates a battery cutoff device (10) according to an embodiment of the present disclosure. The battery cutoff device (10) may include a positive terminal labeled PACK+ and a negative terminal labeled PACK-. The PACK+ terminal may be electrically connected to the positive terminal of a battery pack (12), and the PACK- terminal may be electrically connected to the negative terminal of a battery pack (12). Additionally, the PACK+ terminal may be connected to a main positive relay (14) through a conductor, and the PACK- terminal may be connected to a main negative relay (16) through a separate conductor.

[0042] The main positive relay (14) connects the PACK+ terminal to the LINK+ terminal, and the main negative relay (16) connects the PACK- terminal to the LINK- terminal. The relays (14, 16) may include a switch controlled by a battery cutoff device (10) that can control the flow of current by opening or closing the connection between the battery pack (12) and the capacitor (18). When the main positive relay (14) and the main negative relay (16) are in the open position, no current may flow between the battery pack (12) and the capacitor (18). When the main positive relay (14) is in the closed position and the main negative relay (16) is in the open position, current may flow between the battery pack (12) and the capacitor (18) through the switch mode precharge circuit (20) further described in FIG. 2.

[0043] In some embodiments, a main positive relay (14), a main negative relay (16), or both may further include a fuse (not shown) located in the relay. The fuse may provide additional overcurrent protection to the circuit components.

[0044] The battery disconnect device (10) may further include a switch mode precharge circuit (20) connected to the LINK+ terminal, LINK- terminal and PACK- terminal. The switch mode precharge circuit (20) is described in detail below.

[0045] FIG. 2 illustrates a switch mode precharge circuit (20) of FIG. 1 according to an embodiment of the present disclosure. The switch mode precharge circuit (20) may include a first diode (22), a second diode (24), an inductor (26), a switch (28), a shunt resistor (30), and a switching controller (32).

[0046] The cathode of the second diode (24) may be connected to the LINK+ terminal. The anode of the second diode (24) may be connected to the node (N1) between the inductor (26) and the switch (28). In this direction, the second diode (24) allows current to flow from the inductor (26) to the LINK+ terminal when the switch (28) is in the OFF position, while preventing reverse current and flyback voltage spikes from the LINK+ terminal. The inductor (26) may be additionally connected to the cathode of the first diode (22). The first diode (22) and the second diode (24) may be any suitable diode used in an electrical circuit, including, but not limited to, a silicon diode, a germanium diode, or a Schottky diode. In some embodiments, the first diode (22) and the second diode (24) may be any semiconductor device or circuit configured to operate as a unidirectional switch to control the flow of current.

[0047] The inductor (26) can be connected between the cathode of the first diode (22) and the node (N1) between the second diode (24) and the switch (28). In this position, the inductor (26) can mitigate current fluctuations and store energy to gradually charge the capacitor (18). The anode of the first diode (22) can be connected to the LINK- terminal. In this direction, the first diode (22) can allow current to flow from the LINK- terminal to the inductor (26).

[0048] The switch (28) can be opened or closed in response to a signal from the switching controller (32), which will be described in detail below, to limit the current through the precharge circuit (20). The source of the switch (28) is connected to the node (N2) and the shunt resistor (30), and can be connected to the PACK- terminal through the shunt resistor (30). The gate of the switch (28) can be connected to the switching controller (32). The drain of the switch (28) can be connected to the node (N1) between the second diode (24) and the inductor (26). The switch (28) may include any suitable switching element, such as a MOSFET having a source, drain, and gate, and may include other solid-state switching elements.

[0049] The shunt resistor (30) can be connected between the PACK- terminal and the node (N2) between the source of the switch (28) and the switching controller (32). The shunt resistor (30) can be used by the switching controller (32) to measure the current flowing from the PACK- terminal through the precharge circuit (20). The switching controller (32) can determine the current by measuring the voltage drop across the shunt resistor (30) and adjust the duty cycle and frequency of the switch (28) based on the determined current, which is described in more detail below. The shunt resistor (30) may include any semiconductor having resistance and suitable for current measurement.

[0050] The switching controller (32) may be operably connected to the switch (28) and may receive input signals from the LINK+ terminal, LINK- terminal, and PACK- terminal. The input signals may include voltage measurements, current measurements, or both. In some embodiments, the switching controller (32) may include an analog-to-digital converter (ADC) (34) and a voltage divider (36). The ADC (34) may be configured to convert analog voltage measurements and analog current measurements into digital signals that the switching controller (32) can use for further calculations. The voltage divider (36) may be configured to step down the voltage measurements to a level (e.g., 5V) suitable for the input of the ADC (34).

[0051] The switching controller (32) may receive feedback regarding the current flow through the precharge circuit (20) at the PACK- terminal from the shunt resistor (30), which is described in more detail below. In some embodiments, the switching controller (32) may determine the current at the PACK- terminal by measuring the voltage drop across the shunt resistor (30) and using an ADC (34) and Ohm's law (V=I*R). In other embodiments, the switching controller (32) may determine the current flow through the precharge circuit (20) by measuring the current at the LINK+ terminal and / or the LINK- terminal.

[0052] The switching controller (32) can open or close the switch (28) in response to the current flow through the precharge circuit (20). Based on the voltage measurements at the LINK+ and LINK- terminals and the current measurements at the PACK- terminal, the precharge circuit (20) can calculate the duty cycle and the switching frequency. The duty cycle and the switching frequency are key parameters that determine the operation of the switch (28). The duty cycle refers to the rate of one cycle in which the signal or system is active, and the switching frequency refers to the rate at which the switch is turned on and off. By adjusting these parameters, the precharge circuit (20) can effectively control the current flow for precharging the capacitor (18). In some embodiments, the switching frequency may be determined by the voltage measured at the LINK+ and LINK- terminals, and the duty cycle may be determined by the current measured at the PACK- terminal.

[0053] The switching controller (32) can adjust the duty cycle and frequency of the switch (28) in real time based on the current flow through the precharge circuit (20) and the output voltage. The output voltage may be determined by the switching controller (32) based on the voltage level detected at the LINK+ terminal and / or LINK- terminal. To determine the voltage, the switching controller (32) may reduce the voltage input from the LINK+ terminal and LINK- terminal to 5V or less. In some embodiments, the switching controller (32) may dynamically adjust the duty cycle and frequency of the switch (28) using pulse width modulation (PWM) or a similar control method. By controlling the current flow through the precharge circuit (20) in this way, the switching controller (32) prevents a surge of inrush current that could cause a gradual increase in current and damage circuit components. In another embodiment, the switching controller (32) can adjust the duty cycle and frequency of the switch (28) in real time based on the current measured at the LINK+ terminal and / or LINK- terminal, the output voltage measured at the LINK+ terminal and / or LINK- terminal, and the current measured at the PACK- terminal.

[0054] The switching controller (32) may be configured to perform various diagnostic and protection functions. The switching controller (32) may perform diagnostic checks based on measurements received from the LINK+ terminal, LINK- terminal, and shunt resistor (30), and timing information associated with these measurements. The switching controller (32) may verify the integrity of the precharge circuit (20) by checking for open circuits, short circuits, overload conditions, or other self-protective diagnostic functions. If an anomaly is detected, the switching controller (32) may perform an appropriate error handling routine to resolve the anomaly. In some embodiments, if an anomaly is detected, the switching controller (32) may stop the precharge process to prevent further damage and issue a fault signal or warning for maintenance. In other embodiments, the switching controller (32) may block the precharge circuit (20) to prevent damage to other system components. The switching controller (32) may also log the anomaly and disable further charging until the anomaly is resolved.

[0055] FIG. 3 illustrates a process (300) for controlling an inrush current in a high-voltage power system using a switch-mode precharge circuit (20) according to an embodiment of the present disclosure. In an embodiment, the high-voltage power system may operate at 400 V. In another embodiment, the high-voltage power system may include a system operating at 300, 500, or 800 V, or a system operating at a selected voltage or voltage range between 300 and 800 V.

[0056] In 302, the main positive relay (14) is closed by the battery cutoff device (10) to start the precharge process. The main negative relay (16) is kept open.

[0057] In 304, the switching controller (32) of the precharge circuit (20) can be driven by the precharge voltage at the LINK+ terminal. At this stage, the precharge voltage may be a battery pack voltage of 400 V. The switching controller (32) may receive input signals from the LINK+ terminal, the LINK- terminal, and the shunt resistor (30), and the input signals may include voltage and current measurements.

[0058] In 306, the switching controller (32) can initialize the switch (28) and begin dynamically adjusting the frequency and duty cycle of the switch (28) using PWM. The switching controller (32) can gradually increase the duty cycle so that the switch (28) is intermittently closed. This step indicates the start of a precharge phase in which a small amount of current begins to flow through the precharge circuit (20).

[0059] In 308, the current flow through the shunt resistor (30) is continuously monitored by the switching controller (32). The voltage drop across the shunt resistor (30) is proportional to the current and is provided to the switching controller (32) as real-time feedback. The switching controller (32) can use the feedback to dynamically adjust the duty cycle of the switch (28) so that the current increases smoothly and gradually.

[0060] In 310, when the LINK- terminal reaches a first predetermined voltage level, the battery disconnect device (10) closes the main negative relay (16). In some embodiments, the first predetermined voltage level may be 5 V or a value close thereto.

[0061] In step 312, the switching controller (32) continues to adjust the duty cycle of the switch (28) until the LINK- terminal reaches a second predetermined voltage level. The second predetermined voltage may be selected to ensure that the capacitor is sufficiently charged without a sudden current inrush. In some embodiments, the second predetermined voltage level may be 0 V or a value close thereto, or may be in the range between 0 V and 1 V. When the capacitor (18) reaches the second predetermined voltage, in step 312, the switching controller (32) may keep the switch (28) closed to allow a continuous DC current flow from the battery pack (12) to the capacitor (18). This fully charges the capacitor (18) and completes the precharge step.

[0062] The description of the embodiments is provided for illustrative and illustrative purposes only. It is not intended to be complete or limiting of the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and may be used in selected embodiments even if not specifically illustrated or described. Additionally, the same embodiment may be modified in various ways. Such modifications should not be construed as being outside the scope of the disclosure, and all such modifications are intended to be included within the scope of the rights of the disclosure.

Claims

1. A battery link configured to be connected to a battery for supplying power, A capacitor link configured to be connected to a capacitor for receiving power from the above-mentioned battery, and It includes a precharge circuit connected in series between the battery link and the capacitor link and configured to limit the inrush current to the capacitor during initial power connection, The above precharge circuit is, A switching mechanism configured to switch between open and closed states, A shunt resistor for monitoring current, and It includes a controller connected to the switching mechanism to enable operation and configured to control the duty cycle of the switching mechanism. The controller dynamically adjusts the duty cycle of the switching mechanism to intermittently close the switching mechanism during a stabilization period until a predetermined voltage is reached, thereby transitioning from an open state to a closed state, and when the predetermined voltage is reached, the controller maintains the switching mechanism in a closed state to allow a continuous direct current to flow from the battery to the capacitor. Switch mode control circuit.

2. In Paragraph 1, The above precharge circuit is a switch mode control circuit connected to the negative terminal of the battery link.

3. In Paragraph 1, The above controller is a switch-mode control circuit that dynamically adjusts the duty cycle using pulse width modulation.

4. In Paragraph 3, A switch mode control circuit that dynamically adjusts the duty cycle, including changing the frequency of the pulse width modulation.

5. In Paragraph 1, The above controller is a switch mode control circuit that dynamically adjusts the duty cycle in real time based on the current of the capacitor link, the output voltage of the capacitor link, and the current measured at the negative terminal of the battery through the precharge circuit.

6. In Paragraph 1, The above switching mechanism is a switch mode control circuit, which is one or more MOSFETs or other solid-state switches.

7. In Paragraph 1, The above precharge circuit is a switch-mode control circuit configured to monitor at least one of an open circuit, an overload, and a short circuit.

8. In Paragraph 1, A switch mode control circuit in which the above predetermined voltage is approximately 0 V.

9. In Paragraph 1, A switch mode control circuit that, when the above-mentioned predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a continuous direct current flows from the battery to the capacitor until the capacitor is fully charged.

10. A battery configured to supply power, A capacitor configured to receive power from the above-mentioned battery, and It includes a precharge circuit connected in series between the battery and the capacitor, configured to limit the current flowing into the capacitor during the initial connection of the battery, and The above precharge circuit is, A switching mechanism configured to switch between an open state and a closed state, and It includes a controller connected to the switching mechanism to enable operation and configured to control the duty cycle of the switching mechanism. The controller dynamically adjusts the duty cycle of the switching mechanism to intermittently close the switching mechanism during a stabilization period until a predetermined voltage is reached, thereby transitioning from an open state to a closed state, and when the predetermined voltage is reached, the controller maintains the switching mechanism in a closed state to allow a continuous direct current to flow from the battery to the capacitor. Switch mode control system.

11. In Paragraph 10, The above precharge circuit is a switch mode control system connected to the negative terminal of the battery.

12. In Paragraph 10, A switch mode control system in which the controller dynamically adjusts the duty cycle using pulse width modulation.

13. In Paragraph 12, A switch mode control system that dynamically adjusts the duty cycle, including changing the frequency of the pulse width modulation.

14. In Paragraph 10, The above controller is a switch mode control system that dynamically adjusts the duty cycle in real time based on the current of the capacitor, the output voltage of the capacitor, and the current measured at the negative terminal of the battery through the precharge circuit.

15. In Paragraph 10, The above switching mechanism is a switch mode control system, wherein the switching mechanism is one or more MOSFETs or other solid-state switches.

16. In Paragraph 10, The above precharge circuit is a switch-mode control system configured to monitor at least one of an open circuit, an overload, and a short circuit.

17. In Paragraph 10, A switch mode control system in which the above predetermined voltage is approximately 0 V.

18. In Paragraph 10, A switch mode control system in which, when the above-mentioned predetermined voltage is reached, the controller maintains the switching mechanism in a closed state so that a continuous direct current flows from the battery to the capacitor until the capacitor is fully charged.

19. A battery link configured to be connected to a battery for supplying power, A capacitor link configured to be connected to a capacitor for receiving power from the above-mentioned battery, and It includes a precharge circuit connected in series between the battery link and the capacitor link and configured to limit the inrush current to the capacitor during initial power connection, The above precharge circuit is, A switching mechanism configured to switch between open and closed states, A shunt resistor connected to the battery negative terminal to monitor current flow, and It includes a controller connected to the switching mechanism to enable operation and configured to control the duty cycle of the switching mechanism. The controller dynamically adjusts the duty cycle of the switching mechanism to intermittently close the switching mechanism during a stabilization period until a predetermined voltage is reached, thereby transitioning from an open state to a closed state, and upon reaching the predetermined voltage, the controller maintains the switching mechanism in a closed state so that a direct current continuously flows from the battery to the capacitor until the capacitor is fully charged. Switch mode control circuit.

20. In Paragraph 19, The above controller is a switch mode control circuit that dynamically adjusts the duty cycle in real time based on the current of the capacitor link, the output voltage of the capacitor link, and the current measured at the negative terminal of the battery through the precharge circuit.

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