Direct current conversion device

Abstract

This application provides a DC-DC converter, belonging to the field of power control technology. The device includes: a DC voltage input terminal for receiving an input DC voltage; an input-side voltage sampling circuit including a first sampling circuit and a second sampling circuit; the first sampling circuit samples a first input terminal voltage; the second sampling circuit samples a second input terminal voltage; a voltage conversion circuit; and a control circuit for controlling the operating state of the input-side main contactor. The control circuit is further used to determine whether the input-side main contactor has malfunctioned based on the first and second input terminal voltages. When the input-side main contactor is in a closed state, the control circuit also controls the voltage conversion circuit to boost the input DC voltage to obtain a target DC voltage. This application can detect whether a contactor within the device has malfunctioned without requiring additional detection circuitry, thereby improving the reliability of the device.

Description

Technical Field

[0001] This application relates to the field of power control technology, and in particular to a DC-DC converter. Background Technology

[0002] In the field of power control technology, DC-DC converters are used to boost the lower DC voltage from the battery side to output a higher DC voltage, thereby providing the required DC voltage for power systems such as data centers or communication base stations during power outages. However, during operation, the contactors within these DC-DC converters may not function as expected, such as abnormal opening or closing, leading to device malfunctions and reduced reliability.

[0003] Currently, some methods exist in the industry to improve these DC-DC converters by adding extra detection circuitry to detect contactor failures, thereby enhancing the converter's reliability. However, these improved DC-DC converters rely on additional detection circuitry, increasing the device's complexity and potentially introducing new failure points, resulting in insufficient reliability. Therefore, providing a DC-DC converter that can detect contactor failures without requiring additional detection circuitry, thus improving overall reliability, is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] The main objective of this application is to provide a DC-DC converter that can detect whether a contactor within the device has malfunctioned without the need for additional detection circuitry, thereby improving the reliability of the device.

[0005] This application provides a DC-DC converter, comprising: A DC voltage input terminal, comprising a positive input terminal and a negative input terminal, is used to receive an input DC voltage. An input-side main contactor, wherein the input terminal of the input-side main contactor is electrically connected to the positive input terminal; An input-side voltage sampling circuit includes a first sampling circuit and a second sampling circuit; wherein, the first sampling circuit is connected between the input terminal of the input-side main contactor and the negative input terminal, and is used to sample the first input terminal voltage; the second sampling circuit is connected between the output terminal of the input-side main contactor and the negative input terminal, and is used to sample the second input terminal voltage; A voltage conversion circuit, wherein the input terminal of the voltage conversion circuit is electrically connected to the output terminal of the input-side main contactor and the negative input terminal; The control circuit is electrically connected to the input-side main contactor, the first sampling circuit, the second sampling circuit, and the voltage conversion circuit, respectively, and is used to control the operating state of the input-side main contactor; the control circuit is also used to determine whether the input-side main contactor has malfunctioned based on the first input terminal voltage and the second input terminal voltage; the control circuit is also used to control the voltage conversion circuit to boost the input DC voltage to obtain the target DC voltage when the operating state of the input-side main contactor is closed.

[0006] In some embodiments, the DC-DC converter further includes: An input-side pre-charging circuit includes: a first pre-charging switch, a first pre-charging resistor, and a first capacitor; wherein the first pre-charging switch and the first pre-charging resistor are connected in series, the first pre-charging switch is connected to the input terminal of the input-side main contactor, the first pre-charging resistor is connected to the output terminal of the input-side main contactor, and the first capacitor is connected between the output terminal of the input-side main contactor and the negative input terminal; The control circuit is electrically connected to the first precharge switch and is used to control the first precharge switch to turn on when the main contactor on the input side is in the off state to precharge the first capacitor, and to control the first precharge switch to turn off when the first capacitor is precharged.

[0007] In some embodiments, the control circuit is further configured to control the operating state of the input-side main contactor to be closed when the first capacitor pre-charge is completed, and to determine whether the input-side main contactor has failed based on a first difference between the first input terminal voltage and the second input terminal voltage.

[0008] In some embodiments, the control circuit is further configured to control the first precharge switch to open when the operating state of the input-side main contactor is open, and to determine whether the input-side main contactor has a sticking fault based on a second difference between the first input terminal voltage and the second input terminal voltage.

[0009] In some embodiments, the first sampling circuit includes: A voltage divider resistor network is connected between the input terminal of the input-side main contactor and the negative input terminal to divide the input DC voltage. An isolated differential sampler, which is electrically connected to the voltage divider resistor network, is used to obtain a differential sampling voltage; A differential operational amplifier, connected to the isolated differential sampler, is used to amplify the differential sampled voltage to obtain a first input voltage.

[0010] In some embodiments, the voltage divider resistor network includes: a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor; wherein the first resistor, the second resistor, the third resistor, the fourth resistor, and the fifth resistor are connected in series, and the first resistor is electrically connected to the input terminal of the input-side main contactor, and the fifth resistor is electrically connected to the negative input terminal; The isolated differential sampler is electrically connected to both ends of the third resistor.

[0011] In some embodiments, the first sampling circuit further includes: A bias circuit, electrically connected to the differential operational amplifier, is used to provide a zero-point bias voltage.

[0012] In some embodiments, the voltage conversion circuit includes: An inductor, one end of which is connected to the output terminal of the input-side main contactor; A first switching transistor, one end of which is electrically connected to the other end of the inductor, and the other end of which is electrically connected to the negative input terminal; The first diode, the anode of the first diode being electrically connected to the inductor and one end of the first switching transistor; The control circuit is electrically connected to the first switching transistor and is used to control the first switching transistor to be in the on state so that the inductor can store energy. The control circuit is also used to control the first switching transistor to be in the off state so that the inductor can release the stored energy and the induced voltage generated by the inductor is superimposed with the input DC voltage to obtain the target DC voltage.

[0013] In some embodiments, the voltage conversion circuit further includes: A second switching transistor, one end of which is electrically connected to the other end of the inductor; The second diode, the cathode of which is electrically connected to the other end of the second switching transistor; The control circuit is electrically connected to the second switching transistor and is also used to control the operating state of the second switching transistor.

[0014] In some embodiments, the voltage conversion circuit further includes: A fuse is connected in series between the other end of the first switching transistor and the negative input terminal to provide overcurrent protection for the first switching transistor.

[0015] In some embodiments, the voltage conversion circuit further includes: A current isolation sampler is connected in series between one end of the inductor and the input-side main contactor to detect the current in the branch where the inductor is located.

[0016] In some embodiments, the DC-DC converter further includes: An output-side main contactor, the input terminal of which is connected to the output terminal of the voltage conversion circuit; The control circuit is electrically connected to the output-side main contactor and is also used to control the working state of the output-side main contactor. A positive output terminal is connected to the output terminal of the main contactor on the output side; the positive output terminal and the negative input terminal constitute a DC voltage output terminal; the DC voltage output terminal is used to output the target DC voltage when the main contactor on the output side is in the closed state.

[0017] In some embodiments, the DC-DC converter further includes: An output-side voltage sampling circuit, comprising a third sampling circuit and a fourth sampling circuit; wherein, the third sampling circuit is connected between the input terminal of the output-side main contactor and the negative input terminal, and is used to sample the first output terminal voltage; the fourth sampling circuit is connected between the output terminal of the output-side main contactor and the negative input terminal, and is used to sample the second output terminal voltage; The control circuit is electrically connected to the third sampling circuit and the fourth sampling circuit, and is used to determine whether the main contactor on the output side has malfunctioned based on the first output voltage and the second output voltage.

[0018] In some embodiments, the DC-DC converter further includes: The output-side pre-charging circuit includes: a second pre-charging switch, a second pre-charging resistor, and a second capacitor; wherein the second pre-charging switch and the second pre-charging resistor are connected in series, the second pre-charging switch is connected to the input terminal of the output-side main contactor, the second pre-charging resistor is connected to the output terminal of the output-side main contactor, and the second capacitor is connected between the input terminal of the output-side main contactor and the negative input terminal; The control circuit is electrically connected to the second precharge switch and is used to control the second precharge switch to turn on when the main contactor on the output side is in the off state, so as to precharge the second capacitor, and to control the second precharge switch to turn off when the precharge of the second capacitor is completed.

[0019] This application proposes a DC-DC converter, which includes a DC voltage input terminal with a positive and a negative input terminal. The input terminal of the input-side main contactor is electrically connected to the positive input terminal. Input-side voltage sampling circuits are positioned on both sides of the input-side main contactor, with a first sampling circuit connected between the input terminal and the negative input terminal, and a second sampling circuit connected between the output terminal and the negative input terminal. The input terminal of the voltage conversion circuit is electrically connected to the output terminal and the negative input terminal of the input-side main contactor. A control circuit is electrically connected to the input-side main contactor, the first sampling circuit, the second sampling circuit, and the voltage conversion circuit to control the operating state of the input-side main contactor. The control circuit determines whether a fault has occurred in the input-side main contactor based on the first and second input terminal voltages. When the input-side main contactor is in a closed state, the control circuit boosts the input DC voltage to obtain the target DC voltage. Thus, this embodiment of the application can utilize the input-side voltage sampling circuit within the device to collect voltage, and determine whether the input-side main contactor has malfunctioned based on the first and second input terminal voltages through the control circuit, without the need for additional detection circuits, thereby avoiding the complexity and new fault points introduced by additional detection circuits; simultaneously, the voltage conversion circuit can be controlled to boost the input DC voltage to obtain the target DC voltage to meet the voltage requirements of the power system. In other words, this embodiment of the application can detect whether the contactor within the device has malfunctioned without the need for additional detection circuits, thereby improving the reliability of the device. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a DC-DC converter provided in an embodiment of this application; Figure 2 This is another structural schematic diagram of a DC-DC converter provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the first sampling circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of a voltage conversion circuit provided in an embodiment of this application; Figure 5 This is another structural schematic diagram of the DC-DC converter provided in the embodiments of this application.

[0021] Figure label: The circuit includes: DC voltage input terminal 100, positive input terminal 110, negative input terminal 120; input-side main contactor 200; input-side voltage sampling circuit 300, first sampling circuit 310, voltage divider resistor network 311, isolation differential sampler 312, differential operational amplifier 313, second sampling circuit 320; voltage conversion circuit 400, including inductor 410, first switching transistor 420, first diode 430, second switching transistor 440, second diode 450, fuse 460, current isolation sampler 470; first precharge switch 510, first precharge resistor 520, and first capacitor 530; output-side main contactor 600; positive output terminal 700; output-side voltage sampling circuit 800, third sampling circuit 810, and fourth sampling circuit 820; second precharge switch 910, second precharge resistor 920, and second capacitor 930. Detailed Implementation

[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0024] In power systems such as data centers or communication base stations, mains power supply may be suddenly interrupted due to external power grid failures or planned maintenance. To ensure the continued operation of these critical power systems during power outages, batteries are typically configured as backup power sources. For example, a battery consisting of multiple lithium batteries connected in series is used to provide backup power to servers when mains power is interrupted. However, the DC voltage output by the battery is often lower than the voltage level required for the normal operation of the power system. Therefore, in the field of power control technology, DC-DC converters are used to boost the lower DC voltage from the battery side to output a higher DC voltage, thereby providing the required DC voltage for the power system during power outages. However, during operation, the contactors within these DC-DC converters may not function as expected, such as abnormal opening or closing, leading to device malfunction and reduced reliability.

[0025] Currently, some methods exist in the industry to improve the reliability of such DC-DC converters by adding additional detection circuits to detect contactor failures. However, these improved DC-DC converters rely on additional detection circuits, increasing the complexity of the device and potentially introducing new failure points, resulting in insufficient reliability. Therefore, this application provides a DC-DC converter that can detect contactor failures without requiring additional detection circuits, thereby improving the device's reliability.

[0026] The following will combine Figure 1 A schematic diagram of a DC-DC converter provided in the embodiments of this application will be clearly and completely described. Obviously, the embodiments described below are some embodiments of this application, not all embodiments.

[0027] refer to Figure 1 , Figure 1 This is a schematic diagram of a DC-DC converter provided in an embodiment of this application, including: a DC voltage input terminal 100, an input-side main contactor 200, an input-side voltage sampling circuit 300, a voltage conversion circuit 400, and a control circuit; DC voltage input terminal 100 includes a positive input terminal 110 and a negative input terminal 120. DC voltage input terminal 100 is used to receive input DC voltage. The input side main contactor 200 has its input terminal electrically connected to the positive input terminal 110. The input-side voltage sampling circuit 300 includes a first sampling circuit 310 and a second sampling circuit 320. The first sampling circuit 310 is connected between the input terminal of the input-side main contactor 200 and the negative input terminal 120 to sample the first input terminal voltage. The second sampling circuit 320 is connected between the output terminal of the input-side main contactor 200 and the negative input terminal 120 to sample the second input terminal voltage. The voltage conversion circuit 400 has its input terminal electrically connected to the output terminal and the negative input terminal 120 of the input-side main contactor 200. The control circuit is electrically connected to the input-side main contactor 200, the first sampling circuit 310, the second sampling circuit 320, and the voltage conversion circuit 400, respectively, and is used to control the working state of the input-side main contactor 200. The control circuit is also used to determine whether the input-side main contactor 200 has malfunctioned based on the first input terminal voltage and the second input terminal voltage. The control circuit is also used to control the voltage conversion circuit 400 to boost the input DC voltage to obtain the target DC voltage when the input-side main contactor 200 is in the closed state.

[0028] In this embodiment, the DC voltage input terminal 100 can refer to a port structure for receiving an external input DC voltage. The input DC voltage can refer to a voltage output by a battery whose direction does not change over time. For example, the input DC voltage can be a 350-volt DC voltage output by the battery; or, it can be a 500-volt DC voltage output by the battery. It is understood that the specific value of the input DC voltage can be adjusted according to the actual output of the battery, but it is usually lower than the voltage level required for the normal operation of the power system. The DC voltage input terminal 100 includes a positive input terminal 110 and a negative input terminal 120. The positive input terminal 110 can refer to the conductive terminal in the DC voltage input terminal 100 used to connect to the positive terminal of an external battery. For example, the positive input terminal 110 can be a copper terminal block that is fixedly connected to the positive output line of the battery by a bolt; or, the positive input terminal 110 can be a nickel-plated plug-in terminal that is quickly connected to the positive output line of the battery by a plug-in method. It is understood that the specific material and connection method of the positive input terminal 110 can be adjusted according to actual needs. The negative input terminal 120 can refer to the conductive terminal in the DC voltage input terminal 100 used to connect to the negative terminal of an external battery. For example, the negative input terminal 120 can be a copper grounding terminal connected to the negative output line of the battery; or, the negative input terminal 120 can be a nickel-plated bus terminal used to connect to the negative output line of the battery. It is understood that the specific material and connection method of the negative input terminal 120 can be adjusted according to actual needs. The input-side main contactor 200 can refer to an electrically controlled switching device with closing and opening functions. For example, such as... Figure 1 As shown, the input terminal of the input-side main contactor 200 is electrically connected to the positive input terminal 110. The input-side main contactor 200 can be a high-voltage DC contactor or an electromagnetic contactor; the specific type of the input-side main contactor 200 can be adjusted according to actual needs.

[0029] The input-side voltage sampling circuit 300 can refer to a circuit structure disposed on both sides of the input-side main contactor 200 for separately collecting the voltages on both sides of the input-side main contactor 200. The input-side voltage sampling circuit 300 includes a first sampling circuit 310 and a second sampling circuit 320. The first sampling circuit 310 can refer to a detection circuit used to collect and convert the voltage between the input terminal and the negative input terminal 120 of the input-side main contactor 200. For example, as... Figure 1As shown, the first sampling circuit 310 is connected between the input terminal of the input-side main contactor 200 and the negative input terminal 120. The first sampling circuit 310 can be a resistor divider sampling circuit or an isolated sampling circuit; the specific type of the first sampling circuit 310 can be adjusted according to actual needs. The first input terminal voltage can refer to the voltage value obtained after the first sampling circuit 310 samples the voltage between the input terminal of the input-side main contactor 200 and the negative input terminal 120. The second sampling circuit 320 can refer to a detection circuit used to acquire and convert the voltage between the output terminal of the input-side main contactor 200 and the negative input terminal 120. For example, as... Figure 1 As shown, the second sampling circuit 320 is connected between the output terminal of the input-side main contactor 200 and the negative input terminal 120. The second sampling circuit 320 can be a resistor divider sampling circuit or an isolated sampling circuit; the specific type of the second sampling circuit 320 can be adjusted according to actual needs. The second input terminal voltage can refer to the voltage value obtained after the second sampling circuit 320 samples the voltage between the output terminal of the input-side main contactor 200 and the negative input terminal 120. It can be understood that the first sampling circuit 310 and the second sampling circuit 320 can adopt the same or different circuit structures. For example, both can adopt resistor divider sampling circuits, or the first sampling circuit 310 can adopt a resistor divider sampling circuit while the second sampling circuit 320 can adopt an isolated sampling circuit.

[0030] Voltage conversion circuit 400 can refer to a power conversion circuit used to boost the input DC voltage. For example, such as... Figure 1As shown, the input terminal of the voltage conversion circuit 400 is electrically connected to the output terminal and negative input terminal 120 of the input-side main contactor 200. The voltage conversion circuit 400 can be a boost voltage conversion circuit or a multi-channel interleaved parallel power conversion circuit; the specific type of the voltage conversion circuit 400 can be adjusted according to actual needs. Boost conversion refers to the process of converting a lower DC voltage to a higher DC voltage. The control circuit refers to the circuit used to coordinate and control the input-side main contactor 200, the first sampling circuit 310, the second sampling circuit 320, and the voltage conversion circuit 400. For example, the control circuit can be a microcontroller, which receives the voltage signals output by the first sampling circuit 310 and the second sampling circuit 320, determines whether the input-side main contactor 200 has malfunctioned based on the difference between the first input voltage and the second input voltage, and controls the operating state of the input-side main contactor 200 to be closed or open. When the input-side main contactor 200 is in the closed state, it controls the voltage conversion circuit 400 to boost the input DC voltage to obtain the target DC voltage. Alternatively, the control circuit can also be a digital signal processor, which receives the voltage signals output by the first sampling circuit 310 and the second sampling circuit 320, determines whether the input-side main contactor 200 has malfunctioned based on the difference between the first input voltage and the second input voltage, and controls the operating state of the input-side main contactor 200 to be closed or open. When the input-side main contactor 200 is in the closed state, it controls the voltage conversion circuit 400 to boost the input DC voltage to obtain the target DC voltage. The specific type of control circuit can be adjusted according to actual needs. The target DC voltage refers to the DC voltage obtained by the voltage conversion circuit 400 after boosting the input DC voltage, which is higher than the input DC voltage. For example, when the input DC voltage is 350 volts, the target DC voltage can be 800 volts to meet the needs of the power system; or, when the input DC voltage is 500 volts, the target DC voltage can be 850 volts to meet the needs of the power system. It should be noted that after the voltage conversion circuit 400 outputs the target DC voltage, it can be output to the external power system through the output port of the DC-DC converter to meet the voltage requirements of the external electrical equipment.

[0031] It is understood that, in this embodiment of the application, a DC voltage input terminal 100 is provided, and a positive input terminal 110 and a negative input terminal 120 are configured on the DC voltage input terminal 100; the input terminal of the input-side main contactor 200 is electrically connected to the positive input terminal 110; the input-side voltage sampling circuit 300 is disposed on both sides of the input-side main contactor 200, such that the first sampling circuit 310 is connected between the input terminal of the input-side main contactor 200 and the negative input terminal 120, and the second sampling circuit 320 is connected between the output terminal of the input-side main contactor 200 and the negative input terminal 120; the voltage is converted... The input terminal of the switching circuit 400 is electrically connected to the output terminal and negative input terminal 120 of the input-side main contactor 200. The control circuit is electrically connected to the input-side main contactor 200, the first sampling circuit 310, the second sampling circuit 320, and the voltage conversion circuit 400 respectively. The control circuit controls the working state of the input-side main contactor 200, determines whether the input-side main contactor 200 has malfunctioned based on the first input terminal voltage and the second input terminal voltage, and controls the voltage conversion circuit 400 to boost the input DC voltage to obtain the target DC voltage when the input-side main contactor 200 is in the closed state. Thus, in this embodiment, the input-side voltage sampling circuit 300 within the device can collect voltage, and the control circuit can determine whether the input-side main contactor 200 has malfunctioned based on the first input terminal voltage and the second input terminal voltage, without the need for additional detection circuits, thereby avoiding the complexity and new fault points introduced by additional detection circuits. At the same time, the voltage conversion circuit 400 can be controlled to boost the input DC voltage to obtain the target DC voltage to meet the voltage requirements of the power system. That is, in this embodiment, the contactor malfunction within the device can be detected without additional detection circuits, thereby improving the reliability of the device.

[0032] In some embodiments of this application, the DC-DC converter further includes an input-side pre-charge circuit. The input-side pre-charge circuit can refer to a protection circuit used to pre-charge the output terminal of the input-side main contactor 200 when the input-side main contactor 200 is in the open state, thereby reducing the inrush current generated when the input-side main contactor 200 is in the closed state. The input-side pre-charge circuit includes a first pre-charge switch 510, a first pre-charge resistor 520, and a first capacitor 530. The first pre-charge switch 510 can refer to an electronically controlled switch device with on and off functions. For example, please refer to... Figure 2 , Figure 2 This is another structural schematic diagram of the DC-DC converter provided in the embodiments of this application, as shown below. Figure 2As shown, the first pre-charge switch 510 is connected in series with the first pre-charge resistor 520, and the first pre-charge switch 510 is connected to the input terminal of the input-side main contactor 200. The first pre-charge switch 510 can be an electromagnetic contactor or a relay; the specific type of the first pre-charge switch 510 can be adjusted according to actual needs. The first pre-charge resistor 520 can refer to a resistive device used to limit the current magnitude. For example, such as... Figure 2 As shown, the first pre-charge resistor 520 is connected in series with the first pre-charge switch 510, and the first pre-charge resistor 520 is connected to the output terminal of the input-side main contactor 200. The first pre-charge resistor 520 can be a power resistor or a current-limiting resistor; the specific type of the first pre-charge resistor 520 can be adjusted according to actual needs. The first capacitor 530 can refer to a capacitor element used to store electrical energy. For example, as... Figure 2 As shown, the first capacitor 530 is connected between the output terminal of the input-side main contactor 200 and the negative input terminal 120. The first capacitor 530 can be an electrolytic capacitor or a film capacitor; the specific type of the first capacitor 530 can be adjusted according to actual needs.

[0033] It should be noted that the control circuit is also electrically connected to the first precharge switch 510, which is used to control the first precharge switch 510 to conduct when the main contactor 200 on the input side is in the open state, so that the input DC voltage is limited by the first precharge resistor 520 and precharges the first capacitor 530, thereby establishing a voltage across the first capacitor 530. When the first capacitor 530 is precharged, the first precharge switch 510 is controlled to open to end the precharge process.

[0034] It is understood that, by setting up an input-side pre-charging circuit and configuring a first pre-charging switch 510, a first pre-charging resistor 520, and a first capacitor 530 in the input-side pre-charging circuit, the control circuit controls the first pre-charging switch 510 to conduct when the input-side main contactor 200 is in the open state. After current limiting by the first pre-charging resistor 520, the first capacitor 530 is pre-charged to establish a voltage across the first capacitor 530. When the input-side main contactor 200 is in the closed state, the voltages on both sides of the input-side main contactor 200 are brought closer together, thereby reducing the inrush current generated when the input-side main contactor 200 is closed and reducing the risk of damage to the input-side main contactor 200 due to a large inrush current, thereby further improving the reliability of the device.

[0035] In some embodiments of this application, the control circuit is further configured to, when the first capacitor 530 is pre-charged, control the first pre-charge switch 510 to open, ending the pre-charge process, and then control the input-side main contactor 200 to be in a closed state. At this time, the first sampling circuit 310 samples the voltage between the input terminal and the negative input terminal 120 of the input-side main contactor 200 to obtain the first input terminal voltage; the second sampling circuit 320 samples the voltage between the output terminal and the negative input terminal 120 of the input-side main contactor 200 to obtain the second input terminal voltage. The control circuit calculates a first difference between the first and second input terminal voltages and determines whether the input-side main contactor 200 has experienced a failure based on the first difference. The first difference can refer to the voltage difference between the first and second input terminal voltages. A failure can refer to an abnormal state where the input and output terminals of the input-side main contactor 200 fail to conduct properly after receiving a closing command. Since the voltage difference between the input and output terminals of the input-side main contactor 200 is extremely small when it is in the closed state, this voltage difference reflects whether it is truly in a closed state. Therefore, if the voltage difference indicated by the first difference is large, it can be determined that the input-side main contactor 200 has failed; conversely, if the voltage difference indicated by the first difference is small or zero, it can be determined that the input-side main contactor 200 has not failed. For example, when the first difference is greater than 1 volt, the control circuit determines that the input-side main contactor 200 has failed; or, when the first difference is less than or equal to 1 volt, the control circuit determines that the input-side main contactor 200 has not failed. It should be noted that 1 volt is an example value considering voltage sampling error; the specific value can be adjusted according to the actual sampling accuracy.

[0036] In some embodiments of this application, the control circuit is further configured to control the first precharge switch 510 to open when the input-side main contactor 200 is in an open state, and determine whether the input-side main contactor 200 has experienced a sticking fault based on a second difference between the first input terminal voltage and the second input terminal voltage. At this time, the first sampling circuit 310 samples the voltage between the input terminal of the input-side main contactor 200 and the negative input terminal 120 to obtain the first input terminal voltage; the second sampling circuit 320 samples the voltage between the output terminal of the input-side main contactor 200 and the negative input terminal 120 to obtain the second input terminal voltage. The control circuit calculates the second difference between the first input terminal voltage and the second input terminal voltage, and determines whether the input-side main contactor 200 has experienced a sticking fault based on the second difference. The second difference can refer to the voltage difference between the first input terminal voltage and the second input terminal voltage. A sticking fault can refer to an abnormal state where the input terminal and output terminal of the input-side main contactor 200 fail to truly disconnect after receiving a disconnect command. When the input-side main contactor 200 is in the open state, the voltage difference between its input and output terminals is relatively large, reflecting whether it is truly in the open state. Therefore, if the voltage difference indicated by the second difference is small or zero, it can be determined that the input-side main contactor 200 has a sticking fault; conversely, if the voltage difference indicated by the second difference is large, it can be determined that the input-side main contactor 200 has not experienced a sticking fault. For example, when the second difference is less than 1 volt, the control circuit determines that the input-side main contactor 200 has a sticking fault; or, when the second difference is greater than or equal to 1 volt, the control circuit determines that the input-side main contactor 200 has not experienced a sticking fault. It should be noted that 1 volt is an example value considering voltage sampling error; the specific value can be adjusted according to the actual sampling accuracy.

[0037] In some embodiments of this application, the first sampling circuit 310 includes a voltage divider resistor network 311, an isolated differential sampler 312, and a differential operational amplifier 313. The voltage divider resistor network 311 can refer to a resistor network used to divide the input DC voltage. For example, please refer to... Figure 3 , Figure 3 This is a schematic diagram of the structure of the first sampling circuit provided in an embodiment of this application, as shown below. Figure 3 As shown, the voltage divider resistor network 311 is connected between the input terminal of the input-side main contactor 200 and the negative input terminal 120. The voltage divider resistor network 311 can be a voltage divider network composed of multiple resistors connected in series; the specific structure of the voltage divider resistor network 311 can be adjusted according to actual needs. The isolation differential sampler 312 can refer to a device used to isolate and sample the voltage after voltage division to obtain a differential sample voltage. For example, such as... Figure 3As shown, the isolation differential sampler 312 is electrically connected to the voltage divider resistor network 311. The isolation differential sampler 312 can be an isolation differential amplifier or an isolation sampling chip; the specific type of the isolation differential sampler 312 can be adjusted according to actual needs. The differential sampling voltage refers to the differential voltage signal output by the isolation differential sampler 312 after isolating and sampling the voltage after voltage division. The differential operational amplifier 313 can refer to a device used to amplify the isolated sampled signal to obtain the first input terminal voltage. For example, such as... Figure 3 As shown, the differential operational amplifier 313 is connected to the isolated differential sampler 312. The differential operational amplifier 313 can be an instrumentation amplifier or a precision operational amplifier; the specific type of the differential operational amplifier 313 can be adjusted according to actual needs.

[0038] It is understood that, in this embodiment, a voltage divider resistor network 311 is set in the first sampling circuit 310, and the voltage divider resistor network 311 is connected between the input terminal of the input-side main contactor 200 and the negative input terminal 120 to divide the input DC voltage, thereby reducing the high input DC voltage to a range suitable for isolation sampling. An isolation differential sampler 312 is electrically connected to the voltage divider resistor network 311 to isolate and sample the divided voltage, thereby obtaining a differential sampling voltage and achieving electrical isolation between the high-voltage side and the low-voltage side. A differential operational amplifier 313 is connected to the isolation differential sampler 312 to amplify the differential sampling voltage, thereby obtaining the first input terminal voltage and improving the accuracy of the sampling signal. Thus, this embodiment can achieve safe and accurate sampling of high-voltage DC voltage through three stages of processing: voltage division, isolation, and amplification, providing an accurate voltage basis for the control circuit to determine whether the input-side main contactor 200 has malfunctioned.

[0039] In some embodiments of this application, the voltage divider resistor network includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor. The first, second, third, fourth, and fifth resistors are connected in series, with the first resistor electrically connected to the input terminal of the input-side main contactor 200, and the fifth resistor electrically connected to the negative input terminal 120. An isolation differential sampler 312 is electrically connected to both ends of the third resistor to isolate and sample the voltage across the third resistor to obtain a differential sampling voltage. For example, the first, second, third, fourth, and fifth resistors can all be 100 kΩ metal film resistors; or, they can be thick film resistors with different resistance values. The specific resistance values ​​and types of the first, second, third, fourth, and fifth resistors can be adjusted according to actual needs.

[0040] It is understood that, in this embodiment of the application, a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor are set in the voltage divider resistor network 311, with the first resistor connected in series and the fifth resistor connected to the input terminal of the input-side main contactor 200, and the fifth resistor connected to the negative input terminal 120. This divides the higher input DC voltage to the two ends of the third resistor to form a low-voltage sampling signal. The isolation differential sampler 312 is electrically connected to the two ends of the third resistor to isolate and sample the low-voltage sampling signal across the third resistor, thereby obtaining a differential sampling voltage and achieving electrical isolation between the high-voltage side and the low-voltage side. In this way, this embodiment of the application can reduce the input DC voltage to a low voltage range suitable for the isolation differential sampler 312 to process by the series voltage divider of the five resistors. At the same time, by using the isolation differential sampler 312 connected across the three ends of the third resistor, the sampling voltage proportional to the input DC voltage is accurately extracted, providing a stable and reliable input for the subsequent amplification processing of the differential operational amplifier 313, thereby improving the sampling accuracy of the first input terminal voltage.

[0041] In some embodiments of this application, the first sampling circuit 310 further includes a bias circuit. The bias circuit can refer to a circuit used to provide a zero-point bias voltage. The bias circuit is electrically connected to the differential operational amplifier 313 and is used to superimpose the zero-point bias voltage onto the output terminal of the differential operational amplifier 313. The zero-point bias voltage can refer to a reference voltage used to distinguish between positive and negative voltages. For example, the zero-point bias voltage can be 1.65 volts or 1.60 volts; the specific value of the zero-point bias voltage can be adjusted according to actual needs. Since the isolated differential sampler 312 adopts a differential sampling structure, and the output terminal of the differential operational amplifier 313 is superimposed with the zero-point bias voltage provided by the bias circuit, the first sampling circuit 310 can identify the positive and negative polarities of the input DC voltage relative to the zero-point bias voltage when sampling the first input terminal voltage. The control circuit can determine whether the DC voltage input terminal 100 is reverse-connected based on the deviation direction of the first input terminal voltage relative to the zero-point bias voltage. For example, when the voltage at the first input terminal is lower than the zero-point bias voltage, it indicates that the polarity of the positive input terminal 110 and the negative input terminal 120 is opposite. The control circuit can determine that the DC voltage input terminal 100 is reverse-connected and control the input-side main contactor 200 to disconnect, thereby stopping the device from operating. Thus, this embodiment of the application can achieve reverse-connection protection using the existing first sampling circuit 310 and bias circuit without adding an additional reverse-connection detection circuit, reducing the possibility of damage to internal components due to reverse battery connection, thereby further improving the reliability of the DC-DC converter.

[0042] In some embodiments of this application, the voltage conversion circuit 400 includes an inductor 410, a first switching transistor 420, and a first diode 430. The inductor 410 can refer to an inductive element used for storing and releasing electrical energy. For example, please refer to... Figure 4 , Figure 4 This is a schematic diagram of a voltage conversion circuit 400 provided in an embodiment of this application, as shown below. Figure 4 As shown, one end of inductor 410 is connected to the output terminal of the input-side main contactor 200. Inductor 410 can be a power inductor or an iron-silicon-aluminum magnetic core inductor; the specific type of inductor 410 can be adjusted according to actual needs. The first switching transistor 420 can refer to a power semiconductor device with on and off functions. For example, as... Figure 4 As shown, one end of the first switching transistor 420 is electrically connected to the other end of the inductor 410, and the other end of the first switching transistor 420 is electrically connected to the negative input terminal 120. The first switching transistor 420 can be an insulated-gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor; the specific type of the first switching transistor 420 can be adjusted according to actual needs. The first diode 430 can refer to a semiconductor device with unidirectional conductivity. For example, such as... Figure 4 As shown, the anode of the first diode 430 is electrically connected to one end of the inductor 410 and the first switching transistor 420. The cathode of the first diode 430 is used to transmit the target DC voltage to the outside when the inductor 410 releases the stored energy, so that the DC-DC converter can provide the target DC voltage to the external power system. The first diode 430 can be a fast recovery diode or a Schottky diode. The specific type of the first diode 430 can be adjusted according to actual needs.

[0043] It should be noted that the control circuit is electrically connected to the first switching transistor 420 and is used to control the first switching transistor 420 to be in the conducting state so that the inductor 410 can store energy. The control circuit is also used to control the first switching transistor 420 to be in the off state so that the inductor 410 can release the stored energy, and the induced voltage generated by the inductor 410 is superimposed on the input DC voltage to obtain the target DC voltage. The induced voltage can refer to the induced electromotive force generated by the inductor when the current changes. For example, when the first switching transistor 420 switches from the conducting state to the off state, the current in the inductor 410 decreases, and an induced voltage is generated across the inductor 410. The direction of this induced voltage is the same as the direction of the input DC voltage, so that the induced voltage is superimposed on the input DC voltage to obtain the target DC voltage.

[0044] It is understood that, in this embodiment of the application, by setting an inductor 410, a first switching transistor 420, and a first diode 430 in the voltage conversion circuit 400, one end of the inductor 410 is connected to the output terminal of the input-side main contactor 200, and the other end of the inductor 410 is electrically connected to one end of the first switching transistor 420 and the anode of the first diode 430. The other end of the first switching transistor 420 is electrically connected to the negative input terminal 120. Thus, when the first switching transistor 420 is in the on state, the inductor 410 stores energy; when the first switching transistor 420 is in the off state, the inductor 410 releases the stored energy, and the induced voltage generated by the inductor 410 is superimposed on the input DC voltage to obtain the target DC voltage. In this way, this embodiment of the application can achieve boost conversion through the inductor 410, the first switching transistor 420, and the first diode 430, converting a lower input DC voltage into a higher target DC voltage to meet the voltage requirements of the power system.

[0045] In some embodiments of this application, the voltage conversion circuit 400 further includes a second switch 440 and a second diode 450. The second switch 440 may refer to a power semiconductor device with on and off functions. For example, as... Figure 4 As shown, one end of the second switch 440 is electrically connected to the other end of the inductor 410. The second switch 440 can be an insulated-gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor; the specific type of the second switch 440 can be adjusted according to actual needs. The second diode 450 can refer to a semiconductor device with unidirectional conductivity. For example, such as... Figure 4 As shown, the cathode of the second diode 450 is electrically connected to the other end of the second switching transistor 440, and the anode of the second diode 450 is used to introduce an external voltage so that the DC-DC converter can be stepped down and charged through the inductor 410. The second diode 450 can be a fast recovery diode or a Schottky diode; the specific type of the second diode 450 can be adjusted according to actual needs.

[0046] It should be noted that the control circuit is electrically connected to the second switching transistor 440 and is also used to control the operating state of the second switching transistor 440. For example, the control circuit can control the operating state of the second switching transistor 440 to be in the on state, so that current flows through the second switching transistor 440 and the inductor 410, and the inductor 410 stores energy; the control circuit can also control the operating state of the second switching transistor 440 to be in the off state, so that the inductor 410 releases the stored energy and forms a freewheeling circuit through the first switching transistor 420, thereby converting the higher DC voltage into a lower DC voltage and realizing step-down charging.

[0047] It is understood that, in this embodiment of the application, a second switch 440 and a second diode 450 are provided in the voltage conversion circuit 400, such that one end of the second switch 440 is electrically connected to the other end of the inductor 410, and the cathode of the second diode 450 is electrically connected to the other end of the second switch 440. Thus, when the control circuit controls the second switch 440 to be in the on state, current flows through the second switch 440 and the inductor 410, and the inductor 410 stores energy. When the control circuit controls the second switch 440 to be in the off state, the inductor 410 releases the stored energy, and a freewheeling circuit is formed through the first switch 420, converting the higher DC voltage to a lower DC voltage to achieve step-down charging. Simultaneously, the unidirectional conductivity of the second diode 450 is used to prevent the discharge current from flowing back through the second switch 440, thereby protecting the second switch 440. Thus, in this embodiment of the application, step-down charging can be achieved through the second switch 440 and the second diode 450, enabling the DC-DC converter to have bidirectional voltage conversion capability and improving the operational reliability of the second switch 440.

[0048] In some embodiments of this application, the voltage conversion circuit 400 further includes a fuse 460. The fuse 460 can refer to a protective device used to automatically melt and disconnect the circuit in the event of an overcurrent. For example, such as... Figure 4 As shown, fuse 460 is connected in series between the other end of the first switching transistor 420 and the negative input terminal 120. Fuse 460 can be a fast-acting fuse or a current-limiting fuse; the specific type of fuse 460 can be adjusted according to actual needs. It should be noted that fuse 460 is used for overcurrent protection of the first switching transistor 420. For example, when the current in the branch containing the first switching transistor 420 increases abnormally, fuse 460 melts and disconnects the branch, thereby protecting the first switching transistor 420 from overcurrent damage.

[0049] It is understood that, in this embodiment of the application, a fuse 460 is provided in the voltage conversion circuit 400, connected in series between the other end of the first switching transistor 420 and the negative input terminal 120. This allows the fuse 460 to blow and disconnect the branch containing the first switching transistor 420 when an overcurrent occurs, thus protecting the first switching transistor 420 from overcurrent damage. In this way, this embodiment of the application achieves overcurrent protection through the fuse 460, reducing the risk of damage to the first switching transistor 420 due to overcurrent and improving the operational reliability of the voltage conversion circuit 400.

[0050] In some embodiments of this application, the voltage conversion circuit 400 further includes a current isolation sampler 470. The current isolation sampler 470 can refer to a device used for isolating and detecting the current in the branch containing the inductor 410. For example, such as... Figure 4As shown, the current isolation sampler 470 is connected in series between one end of the inductor 410 and the input-side main contactor 200. The current isolation sampler 470 can be a Hall current sensor or an isolation operational amplifier; the specific type of the current isolation sampler 470 can be adjusted according to actual needs.

[0051] It should be noted that the current isolation sampler 470 is used to detect the current in the branch where the inductor 410 is located. For example, the current isolation sampler 470 can sample the current flowing through the inductor 410 in real time and transmit the sampled current signal to the control circuit so that the control circuit can adjust the operating state of the voltage conversion circuit 400 according to the current signal.

[0052] It is understood that, in this embodiment of the application, a current isolation sampler 470 is provided in the voltage conversion circuit 400. This sampler 470 is connected in series between one end of the inductor 410 and the input-side main contactor 200, thereby isolating and detecting the current in the branch where the inductor 410 is located, and transmitting the detected current signal to the control circuit. In this way, this embodiment of the application can achieve real-time detection of the inductor branch current through the current isolation sampler 470, providing a current basis for the control circuit to adjust the operating state of the voltage conversion circuit 400, and improving the operating safety and stability of the voltage conversion circuit 400.

[0053] In some embodiments of this application, such as Figure 4 As shown, the voltage conversion circuit 400 includes an inductor 410, a first switching transistor 420, a first diode 430, a second switching transistor 440, a second diode 450, a fuse 460, and a current isolation sampler 470. One end of the inductor 410 is connected to the output terminal of the input-side main contactor 200, and the other end of the inductor 410 is electrically connected to one end of the first switching transistor 420 and the anode of the first diode 430. The other end of the first switching transistor 420 is electrically connected to the negative input terminal 120 via the fuse 460. One end of the second switching transistor 440 is electrically connected to the other end of the inductor 410. The cathode of the second diode 450 is electrically connected to the other end of the second switching transistor 440. The current isolation sampler 470 is connected in series between one end of the inductor 410 and the input-side main contactor 200.

[0054] It should be noted that the DC-DC converter in this embodiment may include a multi-channel voltage conversion circuit 400. The multi-channel voltage conversion circuits 400 are connected in an interleaved parallel manner, and each of the multi-channel voltage conversion circuits 400 is electrically connected to the output terminal and the negative input terminal 120 of the input-side main contactor 200. The control circuit is electrically connected to the first switch 420 and the second switch 440 in each of the voltage conversion circuits 400, respectively, and is used to control the operating state of each first switch 420 and the second switch 440. During boost discharge, the control circuit controls the first switching transistors 420 of each circuit to alternately turn on and off, causing the inductors 410 of each circuit to store and release energy in sequence. The induced voltage generated by each inductor 410 is superimposed on the input DC voltage to achieve high-power boost discharge. During buck charging, the control circuit controls the second switching transistors 440 of each circuit to alternately turn on and off, causing the inductors 410 of each circuit to store and release energy in sequence. The energy released by each inductor 410 forms a freewheeling circuit through each second diode 450, thus achieving buck charging. Thus, in this embodiment, by interleaving and paralleling multiple voltage conversion circuits 400, and with all multiple voltage conversion circuits 400 having completely identical structures, during boost discharge, multiple circuits jointly boost and convert the input DC voltage to the target DC voltage; during buck charging, multiple circuits jointly buck and convert the higher DC voltage to the lower DC voltage. This distributes the high-power discharge current and low-current charging current across multiple circuits, allowing them to share the load and reducing the current load on individual switches, inductors, and diodes, thereby adapting to the different needs of high-power discharge and low-current charging. It is understood that the number of voltage conversion circuits 400 included in the DC-DC converter can be adjusted according to actual needs.

[0055] It should be noted that the DC-DC converter in this embodiment can also be used in parallel with other DC-DC converters. For example, the DC voltage input terminals of multiple DC-DC converters can be connected to different batteries, and the output terminals of the voltage conversion circuits 400 of each DC-DC converter can be connected in parallel to form a common output port, which together provides DC voltage to the external power system. When there is a voltage difference between different batteries, the control circuit can control the second switch 440 in the DC-DC converter corresponding to the battery with the lower voltage to turn on, so that the voltage at the common output port is stepped down by the inductor 410 and the second diode 450, and then charged to the battery with the lower voltage until the voltage of each battery is the same, thus achieving inter-cluster equalization.

[0056] It should be noted that the DC-DC converter in this embodiment can also be used for online capacity verification of a battery. For example, during online capacity verification, the control circuit controls the second switch 440 to conduct, so that the external voltage is stepped down through the inductor 410 and the second diode 450 to charge the battery until it reaches a fully charged state. Then, the control circuit controls the first switch 420 to alternately turn on and off, so that the inductor 410 stores and releases energy, boosting and discharging the stored energy in the battery until it is completely discharged. During this process, the control circuit measures the battery capacity from a fully charged state to a discharged state and compares the measured capacity with the capacity specified at the time of manufacture to determine the battery's health.

[0057] In some embodiments of this application, the DC-DC converter further includes an output-side main contactor 600 and a positive output terminal 700. The output-side main contactor 600 may refer to an electrically controlled switching device with closing and opening functions. For example, please refer to... Figure 5 , Figure 5 This is another structural schematic diagram of the DC-DC converter provided in the embodiments of this application, as shown below. Figure 5 As shown, the input terminal of the output-side main contactor 600 is connected to the output terminal of the voltage conversion circuit 400. The output-side main contactor 600 can be a high-voltage DC contactor or an electromagnetic contactor; the specific type of the output-side main contactor 600 can be adjusted according to actual needs. The positive output terminal 700 can refer to the conductive terminal in the DC voltage output terminal used to connect to the positive terminal of the external power system. For example, as... Figure 5 As shown, the positive output terminal 700 is connected to the output terminal of the main contactor 600 on the output side. The positive output terminal 700 can be a copper terminal block or a nickel-plated plug-in terminal block. The specific material and connection form of the positive output terminal 700 can be adjusted according to actual needs.

[0058] It should be noted that the control circuit is electrically connected to the output-side main contactor 600 and is also used to control the operating state of the output-side main contactor 600. For example, after the voltage conversion circuit 400 outputs the target DC voltage, the control circuit can control the output-side main contactor 600 to be in a closed state, so that the positive output terminal 700 and the negative input terminal 120 form a DC voltage output terminal, and output the target DC voltage to the external power system; or, the control circuit can also control the output-side main contactor 600 to be in an open state, so as to stop the output of the target DC voltage to the external power system.

[0059] It is understood that, in this embodiment of the application, by setting an output-side main contactor 600 and a positive output terminal 700 in the DC-DC converter, the input terminal of the output-side main contactor 600 is connected to the output terminal of the voltage conversion circuit 400, and the positive output terminal 700 is connected to the output terminal of the output-side main contactor 600. Thus, when the output-side main contactor 600 is in the closed state, the positive output terminal 700 and the negative input terminal 120 constitute a DC voltage output terminal, outputting the target DC voltage. In this way, this embodiment of the application can control the external output of the target DC voltage through the output-side main contactor 600, and through the positive output terminal 700 and the negative input terminal 120 forming a complete DC voltage output terminal, realize the power transmission between the DC-DC converter and the external power system.

[0060] It should be noted that, as Figure 4 and Figure 5 As shown, the cathode of the first diode 430 and the anode of the second diode 450 are both electrically connected to the input terminal of the output-side main contactor 600. Thus, during boost discharge, the induced voltage generated by the energy released from the inductor 410 is superimposed on the input DC voltage and output through the cathode of the first diode 430 to the input terminal of the output-side main contactor 600. During buck charging, the external voltage flows into the inductor 410 through the anode of the second diode 450 to charge the battery.

[0061] In some embodiments of this application, the DC-DC converter further includes an output-side voltage sampling circuit 800. The output-side voltage sampling circuit 800 can refer to a circuit structure disposed on both sides of the output-side main contactor 600 for respectively collecting the voltages on both sides of the output-side main contactor 600. For example, as... Figure 5 As shown, the output-side voltage sampling circuit 800 includes a third sampling circuit 810 and a fourth sampling circuit 820. The third sampling circuit 810 is connected between the input terminal and the negative input terminal 120 of the output-side main contactor 600 and is used to sample the first output voltage. The fourth sampling circuit 820 is connected between the output terminal and the negative input terminal 120 of the output-side main contactor 600 and is used to sample the second output voltage. The first output voltage can refer to the voltage value obtained by the third sampling circuit 810 after sampling the voltage between the input terminal and the negative input terminal 120 of the output-side main contactor 600. The second output voltage can refer to the voltage value obtained by the fourth sampling circuit 820 after sampling the voltage between the output terminal and the negative input terminal 120 of the output-side main contactor 600. It should be noted that the circuit structure of the third sampling circuit 810 and the fourth sampling circuit 820 can be the same as the circuit structure of the first sampling circuit 310.

[0062] It should be noted that the control circuit is electrically connected to the third sampling circuit 810 and the fourth sampling circuit 820, and is used to determine whether the output-side main contactor 600 has malfunctioned based on the first output terminal voltage and the second output terminal voltage. For example, the control circuit can determine whether the output-side main contactor 600 has experienced a failure or sticking fault based on the difference between the first output terminal voltage and the second output terminal voltage, and the fault judgment method for the output-side main contactor 600 is the same as the fault judgment method for the input-side main contactor 200.

[0063] It is understood that, in this embodiment of the application, by setting an output-side voltage sampling circuit 800 in the DC-DC converter, a third sampling circuit 810 is connected between the input terminal and the negative input terminal 120 of the output-side main contactor 600, and a fourth sampling circuit 820 is connected between the output terminal and the negative input terminal 120 of the output-side main contactor 600. This allows the third sampling circuit 810 and the fourth sampling circuit 820 to respectively collect the voltages on both sides of the output-side main contactor 600, and the control circuit determines whether a fault has occurred in the output-side main contactor 600 based on the first and second output terminal voltages. Thus, this embodiment of the application can detect whether a fault has occurred in the output-side main contactor 600 using the output-side voltage sampling circuit 800, eliminating the need for an additional detection circuit on the output side. This avoids the complexity and new fault points introduced by additional detection circuits, thereby improving the reliability of the output side of the DC-DC converter.

[0064] In some embodiments of this application, the DC-DC converter further includes an output-side pre-charge circuit. The output-side pre-charge circuit can refer to a protection circuit used to pre-charge the output side when the output-side main contactor 600 is in the open state, thereby reducing the inrush current generated when the output-side main contactor 600 is closed. For example, as... Figure 5 As shown, the output-side pre-charge circuit includes a second pre-charge switch 910, a second pre-charge resistor 920, and a second capacitor 930. The second pre-charge switch 910 and the second pre-charge resistor 920 are connected in series. The second pre-charge switch 910 is connected to the input terminal of the output-side main contactor 600, and the second pre-charge resistor 920 is connected to the output terminal of the output-side main contactor 600. The second capacitor 930 is connected between the input terminal of the output-side main contactor 600 and the negative input terminal 120. The second pre-charge switch 910 can be an electromagnetic contactor or a relay; the second pre-charge resistor 920 can be a power resistor or a current-limiting resistor; and the second capacitor 930 can be an electrolytic capacitor or a film capacitor. The specific types of the second pre-charge switch 910, the second pre-charge resistor 920, and the second capacitor 930 can be adjusted according to actual needs.

[0065] It should be noted that the control circuit is electrically connected to the second precharge switch 910, which is used to control the second precharge switch 910 to conduct when the main contactor 600 on the output side is in the open state, so as to precharge the second capacitor 930, and to control the second precharge switch 910 to open when the second capacitor 930 is precharged.

[0066] It is understood that, in this embodiment of the application, by setting an output-side pre-charging circuit in the DC-DC converter and configuring a second pre-charging switch 910, a second pre-charging resistor 920, and a second capacitor 930 in the output-side pre-charging circuit, the control circuit controls the second pre-charging switch 910 to conduct when the output-side main contactor 600 is in the open state. After current limiting by the second pre-charging resistor 920, the second capacitor 930 is pre-charged to establish a voltage across the second capacitor 930. When the output-side main contactor 600 is in the closed state, the voltages on both sides of the output-side main contactor 600 are brought closer together, thereby reducing the inrush current generated when the output-side main contactor 600 is closed and reducing the risk of damage to the output-side main contactor 600 due to a large inrush current, thereby further improving the reliability of the DC-DC converter.

[0067] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0068] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0069] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0070] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0071] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A DC-DC converter, characterized in that, include: A DC voltage input terminal, comprising a positive input terminal and a negative input terminal, is used to receive an input DC voltage. An input-side main contactor, wherein the input terminal of the input-side main contactor is electrically connected to the positive input terminal; An input-side voltage sampling circuit includes a first sampling circuit and a second sampling circuit; wherein, the first sampling circuit is connected between the input terminal of the input-side main contactor and the negative input terminal, and is used to sample the first input terminal voltage; the second sampling circuit is connected between the output terminal of the input-side main contactor and the negative input terminal, and is used to sample the second input terminal voltage; A voltage conversion circuit, wherein the input terminal of the voltage conversion circuit is electrically connected to the output terminal of the input-side main contactor and the negative input terminal; The control circuit is electrically connected to the input-side main contactor, the first sampling circuit, the second sampling circuit, and the voltage conversion circuit, respectively, and is used to control the operating state of the input-side main contactor; the control circuit is also used to determine whether the input-side main contactor has malfunctioned based on the first input terminal voltage and the second input terminal voltage; the control circuit is also used to control the voltage conversion circuit to boost the input DC voltage to obtain the target DC voltage when the operating state of the input-side main contactor is closed.

2. The DC-DC converter according to claim 1, characterized in that, The DC-DC converter also includes: An input-side pre-charging circuit includes: a first pre-charging switch, a first pre-charging resistor, and a first capacitor; wherein the first pre-charging switch and the first pre-charging resistor are connected in series, the first pre-charging switch is connected to the input terminal of the input-side main contactor, the first pre-charging resistor is connected to the output terminal of the input-side main contactor, and the first capacitor is connected between the output terminal of the input-side main contactor and the negative input terminal; The control circuit is electrically connected to the first precharge switch and is used to control the first precharge switch to turn on when the main contactor on the input side is in the off state to precharge the first capacitor, and to control the first precharge switch to turn off when the first capacitor is precharged.

3. The DC-DC converter according to claim 2, characterized in that, The control circuit is also used to control the working state of the input-side main contactor to be closed when the first capacitor pre-charge is completed, and to determine whether the input-side main contactor has failed based on the first difference between the first input terminal voltage and the second input terminal voltage.

4. The DC-DC converter according to claim 2, characterized in that, The control circuit is also used to control the first precharge switch to open when the main contactor on the input side is in the open state, and to determine whether the main contactor on the input side has a sticking fault based on the second difference between the first input terminal voltage and the second input terminal voltage.

5. The DC-DC converter according to claim 1, characterized in that, The first sampling circuit includes: A voltage divider resistor network is connected between the input terminal of the input-side main contactor and the negative input terminal to divide the input DC voltage. An isolated differential sampler, which is electrically connected to the voltage divider resistor network, is used to obtain a differential sampling voltage; A differential operational amplifier, connected to the isolated differential sampler, is used to amplify the differential sampled voltage to obtain a first input voltage.

6. The DC-DC converter according to claim 5, characterized in that, The voltage divider resistor network includes: a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor; wherein the first resistor, the second resistor, the third resistor, the fourth resistor, and the fifth resistor are connected in series, and the first resistor is electrically connected to the input terminal of the input-side main contactor, and the fifth resistor is electrically connected to the negative input terminal; The isolated differential sampler is electrically connected to both ends of the third resistor.

7. The DC-DC converter according to claim 6, characterized in that, The first sampling circuit further includes: A bias circuit, electrically connected to the differential operational amplifier, is used to provide a zero-point bias voltage.

8. The DC-DC converter according to claim 1, characterized in that, The voltage conversion circuit includes: An inductor, one end of which is connected to the output terminal of the input-side main contactor; A first switching transistor, one end of which is electrically connected to the other end of the inductor, and the other end of which is electrically connected to the negative input terminal; The first diode, the anode of the first diode being electrically connected to the inductor and one end of the first switching transistor; The control circuit is electrically connected to the first switching transistor and is used to control the first switching transistor to be in the on state so that the inductor can store energy. The control circuit is also used to control the first switching transistor to be in the off state so that the inductor can release the stored energy and the induced voltage generated by the inductor is superimposed with the input DC voltage to obtain the target DC voltage.

9. The DC-DC converter according to claim 8, characterized in that, The voltage conversion circuit further includes: A second switching transistor, one end of which is electrically connected to the other end of the inductor; The second diode, the cathode of which is electrically connected to the other end of the second switching transistor; The control circuit is electrically connected to the second switching transistor and is also used to control the operating state of the second switching transistor.

10. The DC-DC converter according to claim 9, characterized in that, The voltage conversion circuit further includes: A fuse is connected in series between the other end of the first switching transistor and the negative input terminal to provide overcurrent protection for the first switching transistor.

11. The DC-DC converter according to claim 9, characterized in that, The voltage conversion circuit further includes: A current isolation sampler is connected in series between one end of the inductor and the input-side main contactor to detect the current in the branch where the inductor is located.

12. The DC-DC converter according to claim 1, characterized in that, The DC-DC converter also includes: An output-side main contactor, the input terminal of which is connected to the output terminal of the voltage conversion circuit; The control circuit is electrically connected to the output-side main contactor and is also used to control the working state of the output-side main contactor. A positive output terminal is connected to the output terminal of the main contactor on the output side; the positive output terminal and the negative input terminal constitute a DC voltage output terminal; the DC voltage output terminal is used to output the target DC voltage when the main contactor on the output side is in the closed state.

13. The DC-DC converter according to claim 12, characterized in that, The DC-DC converter also includes: An output-side voltage sampling circuit, comprising a third sampling circuit and a fourth sampling circuit; wherein, the third sampling circuit is connected between the input terminal of the output-side main contactor and the negative input terminal, and is used to sample the first output terminal voltage; the fourth sampling circuit is connected between the output terminal of the output-side main contactor and the negative input terminal, and is used to sample the second output terminal voltage; The control circuit is electrically connected to the third sampling circuit and the fourth sampling circuit, and is used to determine whether the main contactor on the output side has malfunctioned based on the first output voltage and the second output voltage.

14. The DC-DC converter according to claim 13, characterized in that, The DC-DC converter also includes: The output-side pre-charging circuit includes: a second pre-charging switch, a second pre-charging resistor, and a second capacitor; wherein the second pre-charging switch and the second pre-charging resistor are connected in series, the second pre-charging switch is connected to the input terminal of the output-side main contactor, the second pre-charging resistor is connected to the output terminal of the output-side main contactor, and the second capacitor is connected between the input terminal of the output-side main contactor and the negative input terminal; The control circuit is electrically connected to the second precharge switch and is used to control the second precharge switch to turn on when the main contactor on the output side is in the off state, so as to precharge the second capacitor, and to control the second precharge switch to turn off when the precharge of the second capacitor is completed.

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