High-capacity capacitor pre-charging circuit

Abstract

The utility model discloses a high-capacity capacitor pre-charging circuit which comprises an input voltage circuit, a relay circuit, a buffer circuit, an MCU control circuit, an anti-backflow circuit and an output voltage circuit. One end of the relay circuit is connected with the positive input end of the input voltage circuit, and the other end is connected with the positive output end of the output voltage circuit; the first end of the buffer circuit is connected with the positive input end of the input voltage circuit, the second end is connected with the positive output end of the output voltage circuit, and the third end is connected with the negative output end of the output voltage circuit; one end of the MCU control circuit is connected with the input voltage circuit, and the other end is connected with the buffer circuit; one end of the anti-backflow circuit is connected with the negative input end of the input voltage circuit, and the other end is connected with the negative output end of the output voltage circuit. According to the pre-charging circuit, the anti-backflow circuit is arranged, so that the phenomenon of current backflow of the circuit caused by impact of large current generated in the pre-charging process on the circuit structure is prevented, and the safety and the reliability of the pre-charging circuit are improved.

Description

Technical Field

[0001] This utility model relates to the field of pre-charging circuit technology, and in particular to a large-capacity capacitor pre-charging circuit. Background Technology

[0002] In the drive system of new energy vehicles, the power battery and the motor controller are connected. The motor controller contains a large-capacity capacitor, which needs to be charged during the initial power-on process. Since the capacitor is an energy storage element, if it is not fully charged at the moment the circuit is closed, the charging current will be extremely large. Without limitation, this large current will significantly impact the power supply, rectifier, and other components, potentially damaging related electrical devices and causing circuit failures. Therefore, a pre-charging circuit needs to be added to the power supply system of new energy vehicle drive systems to reduce the inrush current during power-on, preventing damage to the motor controller, main relay, and other components from the instantaneous surge of large current, thus protecting the equipment.

[0003] With the development of new energy vehicle technology, the requirements for pre-charging circuits are becoming increasingly stringent. Existing pre-charging circuits have revealed several shortcomings. The prior art publication number CN221202142U discloses a pre-charging circuit with automatic power resistor protection, the circuit structure of which is as follows: Figure 1 As shown, a pre-charging resistor is set in the circuit to reduce the large current at the moment of power-on, which plays a protective role. However, during the pre-charging process, due to the large instantaneous current, it is easy to damage the load in the circuit, and even the phenomenon of current backflow may occur. The proposed scheme in the pre-charging circuit of the prior art lacks an anti-backflow mechanism, which has a significant impact on the safety and reliability of the pre-charging circuit. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a large-capacity capacitor pre-charging circuit. By setting an anti-backflow circuit, it prevents the phenomenon of current backflow caused by the large current generated during the pre-charging process, thereby improving the safety and reliability of the pre-charging circuit.

[0005] This utility model provides a large-capacity capacitor pre-charging circuit, which includes an input voltage circuit, a relay circuit, a buffer circuit, an MCU control circuit, an anti-backflow circuit, and an output voltage circuit.

[0006] One end of the relay circuit is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the relay circuit is connected to the positive output terminal VOUT+ of the output voltage circuit.

[0007] The first terminal of the buffer circuit is connected to the positive input terminal VIN+ of the input voltage circuit, the second terminal of the buffer circuit is connected to the positive output terminal VOUT+ of the output voltage circuit, and the third terminal of the buffer circuit is connected to the negative output terminal VOUT- of the output voltage circuit.

[0008] One end of the MCU control circuit is connected to the input voltage circuit, and the other end of the MCU control circuit is connected to the buffer circuit;

[0009] One end of the anti-backflow circuit is connected to the negative input terminal VIN- of the input voltage circuit, and the other end of the anti-backflow circuit is connected to the negative output terminal VOUT- of the output voltage circuit.

[0010] Furthermore, the anti-backflow circuit includes a diode D1, which is connected in series between the negative input terminal VIN- of the input voltage circuit and the negative output terminal VOUT- of the output voltage circuit.

[0011] Furthermore, the relay circuit includes relay RELAY1 and relay RELAY2, which are connected in parallel.

[0012] Furthermore, the buffer circuit includes an output capacitor C1, an output capacitor C2, a transistor IGBT2, a pre-charge resistor R1, and a diode VD1;

[0013] One end of the output capacitor C1 is connected to the positive output terminal VOUT+ of the output voltage circuit, and the other end of the output capacitor C1 is connected to the negative output terminal VOUT- of the output voltage circuit. The output capacitor C2 is connected in parallel with the output capacitor C1. The diode VD1, the transistor IGBT2, and the pre-charge resistor R1 are connected in series in sequence, and the diode VD1, the transistor IGBT2, and the pre-charge resistor R1 are connected in parallel across the two ends of the relay circuit. The anode of the diode VD1 is connected to the positive input terminal VIN+ of the input voltage circuit, and the cathode of the diode VD1 is connected to the transistor IGBT2.

[0014] Furthermore, the MCU control circuit includes an MCU connected between the input voltage circuit and the output voltage circuit.

[0015] Furthermore, the MCU control circuit also includes a first optocoupler operation control circuit and a second optocoupler operation control circuit, both of which are connected to the MCU.

[0016] Furthermore, the MCU control circuit also includes an optocoupler output control circuit, which is connected to the MCU.

[0017] Furthermore, the pre-charging circuit also includes a communication circuit, which is connected to the MCU.

[0018] Furthermore, the pre-charging circuit also includes a filtering circuit, which includes a capacitor C3 and a common-mode inductor L1;

[0019] One end of the capacitor C3 is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the capacitor C3 is connected to the negative input terminal VIN- of the input voltage circuit. One end of the common-mode inductor L1 is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the common-mode inductor L1 is connected to the negative input terminal VIN- of the input voltage circuit.

[0020] Furthermore, the pre-charge circuit also includes a current detection circuit, which includes a current detection resistor R2 connected in series between the diode D1 and the common-mode inductor L1.

[0021] This invention provides a large-capacity capacitor pre-charging circuit. By incorporating an anti-backflow circuit, based on the unidirectional conductivity of diodes, it prevents the large current generated during pre-charging from impacting the circuit structure and causing current backflow, thus improving the safety and reliability of the pre-charging circuit. A buffer circuit composed of diodes, pre-charging resistors, and transistors is incorporated to reduce the large current generated at power-on, effectively protecting the circuit. Two optocoupler operation control circuits, one short-circuited and the other connected to 12V-24V, are included to increase the access channels for external signals and filter these signals, ensuring their quality and reliability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a pre-charging circuit structure in the prior art;

[0024] Figure 2 This is an overall block diagram of the pre-charging circuit in an embodiment of this utility model;

[0025] Figure 3 This is a schematic diagram of the pre-charging circuit structure in an embodiment of this utility model. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0027] In this invention, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, actions, components, portions or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, actions, components, portions or combinations thereof.

[0028] It should also be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] This utility model embodiment provides a large-capacity capacitor pre-charging circuit. The pre-charging circuit includes an input voltage circuit, a relay circuit, a buffer circuit, an MCU control circuit, an anti-backflow circuit, and an output voltage circuit. One end of the relay circuit is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the relay circuit is connected to the positive output terminal VOUT+ of the output voltage circuit. The first end of the buffer circuit is connected to the positive input terminal VIN+ of the input voltage circuit, the second end of the buffer circuit is connected to the positive output terminal VOUT+ of the output voltage circuit, and the third end of the buffer circuit is connected to the negative output terminal VOUT- of the output voltage circuit. One end of the MCU control circuit is connected to the input voltage circuit, and the other end of the MCU control circuit is connected to the buffer circuit. One end of the anti-backflow circuit is connected to the negative input terminal VIN- of the input voltage circuit, and the other end of the anti-backflow circuit is connected to the negative output terminal VOUT- of the output voltage circuit.

[0030] In one optional implementation of this embodiment, such as Figure 2 and Figure 3 As shown, Figure 2 The following is an overall block diagram of the pre-charging circuit in an embodiment of the present invention. Figure 3 A schematic diagram of the pre-charging circuit structure in an embodiment of the present invention is shown. The pre-charging circuit includes an input voltage circuit, a relay circuit, a buffer circuit, an MCU control circuit, an anti-backflow circuit, and an output voltage circuit.

[0031] In an optional implementation of this embodiment, one end of the anti-backflow circuit is connected to the negative input terminal VIN- of the input voltage circuit, and the other end of the anti-backflow circuit is connected to the negative output terminal VOUT- of the output voltage circuit.

[0032] Specifically, the anti-backflow circuit includes a diode D1, which is connected in series between the negative input terminal VIN- of the input voltage circuit and the negative output terminal VOUT- of the output voltage circuit.

[0033] Furthermore, the diode D1 is positioned between the input voltage circuit and the output voltage circuit. Due to the unidirectional conductivity of the diode, it can prevent the large current generated during the pre-charging process from impacting the circuit structure and causing current backflow, thereby improving the safety and reliability of the pre-charging circuit.

[0034] In an optional implementation of this embodiment, one end of the relay circuit is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the relay circuit is connected to the positive output terminal VOUT+ of the output voltage circuit.

[0035] Specifically, the relay circuit includes relay RELAY1 and relay RELAY2, which are connected in parallel.

[0036] In an optional implementation of this embodiment, the first terminal of the buffer circuit is connected to the positive input terminal VIN+ of the input voltage circuit, the second terminal of the buffer circuit is connected to the positive output terminal VOUT+ of the output voltage circuit, and the third terminal of the buffer circuit is connected to the negative output terminal VOUT- of the output voltage circuit.

[0037] Specifically, the buffer circuit includes output capacitor C1, output capacitor C2, transistor IGBT2, pre-charge resistor R1, and diode VD1;

[0038] One end of the output capacitor C1 is connected to the positive output terminal VOUT+ of the output voltage circuit, and the other end of the output capacitor C1 is connected to the negative output terminal VOUT- of the output voltage circuit. The output capacitor C2 is connected in parallel with the output capacitor C1. The diode VD1, the transistor IGBT2, and the pre-charge resistor R1 are connected in series in sequence, and the diode VD1, the transistor IGBT2, and the pre-charge resistor R1 are connected in parallel across the two ends of the relay circuit. The anode of the diode VD1 is connected to the positive input terminal VIN+ of the input voltage circuit, and the cathode of the diode VD1 is connected to the transistor IGBT2.

[0039] Furthermore, when applied to devices with high voltage input, the large current generated at the moment the pre-charging circuit is powered on will limit the current magnitude when the pre-charging resistor R1 passes through it, reducing the current magnitude to a certain level within the tolerance range of the relay circuit. Therefore, there is no need to replace it with a high-voltage resistant relay, simplifying the circuit structure and reducing the cost of the relay.

[0040] Furthermore, the IGBT2 transistor acts as a switching transistor, which can turn off the pre-charge circuit at any time, thus playing a control role.

[0041] Furthermore, a diode VD1 is installed. Due to the unidirectional conductivity of the diode, when the positive and negative terminals of the input voltage circuit are reversed, the circuit will be broken, preventing the circuit from being broken down by the instantaneous high voltage of the reverse connection, thus playing a role in circuit protection.

[0042] Furthermore, output capacitors C1 and C2 can be set to store electrical energy during the pre-charging process.

[0043] In an optional implementation of this embodiment, one end of the MCU control circuit is connected to the input voltage circuit, and the other end of the MCU control circuit is connected to the buffer circuit.

[0044] Specifically, the MCU control circuit is located between the input voltage circuit and the buffer circuit to detect the pre-charge voltage generated between the output capacitors C1 and C2 in the input voltage circuit and the buffer circuit. When the voltage difference between the two is 20V or less, the relay circuit is turned on, the current flows through the relay circuit, the transistor IGBT2 is turned off, the current no longer passes through the pre-charge resistor R1, and the pre-charge process ends.

[0045] In an optional implementation of this embodiment, the MCU control circuit includes an MCU connected between the input voltage circuit and the output voltage circuit.

[0046] Specifically, the MCU is used to control the overall operation of the pre-charging circuit.

[0047] In an optional implementation of this embodiment, the MCU control circuit further includes a first optocoupler operation control circuit and a second optocoupler operation control circuit, both of which are connected to the MCU.

[0048] Specifically, the first optocoupler operation control circuit adopts a connection scheme that shorts RUN+ and RUN-, while the second optocoupler operation control circuit adopts a connection scheme that connects to 12V-24V.

[0049] Furthermore, two optocoupler operation control circuits are set up here, one shorted and the other connected to 12V-24V, to increase the access channels for external input signals and to filter external input signals to ensure the quality and reliability of the input signals.

[0050] In an optional implementation of this embodiment, the MCU control circuit further includes an optocoupler output control circuit, which is connected to the MCU.

[0051] In an optional implementation of this embodiment, the pre-charging circuit further includes a communication circuit connected to the MCU.

[0052] In an optional implementation of this embodiment, the pre-charging circuit further includes a filtering circuit, which includes a capacitor C3 and a common-mode inductor L1.

[0053] One end of the capacitor C3 is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the capacitor C3 is connected to the negative input terminal VIN- of the input voltage circuit. One end of the common-mode inductor L1 is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the common-mode inductor L1 is connected to the negative input terminal VIN- of the input voltage circuit.

[0054] Specifically, the filter circuit filters the input voltage signal, thereby improving the pre-charging efficiency of the pre-charging circuit.

[0055] In an optional implementation of this embodiment, the pre-charge circuit further includes a current detection circuit, which includes a current detection resistor R2 connected in series between the diode D1 and the common-mode inductor L1.

[0056] Specifically, the current detection circuit is used to monitor the magnitude of the current generated in the pre-charging circuit.

[0057] In summary, this utility model embodiment proposes a large-capacity capacitor pre-charging circuit. By setting up an anti-backflow circuit, based on the unidirectional conductivity of diodes, it prevents the large current generated during the pre-charging process from impacting the circuit structure and causing current backflow, thus improving the safety and reliability of the pre-charging circuit. A buffer circuit composed of diodes, pre-charging resistors, and transistors is set up to reduce the large current generated at power-on, effectively protecting the circuit. Two optocoupler operation control circuits, one short-circuited and the other connected to 12V-24V, are set up to increase the access channels for external input signals and filter the external input signals to ensure the quality and reliability of the input signals.

[0058] The above provides a detailed description of a large-capacity capacitor pre-charging circuit provided by the embodiments of this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A large-capacity capacitor pre-charging circuit, characterized in that, The pre-charge circuit includes an input voltage circuit, a relay circuit, a buffer circuit, an MCU control circuit, an anti-backflow circuit, and an output voltage circuit. One end of the relay circuit is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the relay circuit is connected to the positive output terminal VOUT+ of the output voltage circuit. The first terminal of the buffer circuit is connected to the positive input terminal VIN+ of the input voltage circuit, the second terminal of the buffer circuit is connected to the positive output terminal VOUT+ of the output voltage circuit, and the third terminal of the buffer circuit is connected to the negative output terminal VOUT- of the output voltage circuit. One end of the MCU control circuit is connected to the input voltage circuit, and the other end of the MCU control circuit is connected to the buffer circuit; One end of the anti-backflow circuit is connected to the negative input terminal VIN- of the input voltage circuit, and the other end of the anti-backflow circuit is connected to the negative output terminal VOUT- of the output voltage circuit.

2. The large-capacity capacitor pre-charging circuit as described in claim 1, characterized in that, The backflow prevention circuit includes a diode D1, which is connected in series between the negative input terminal VIN- of the input voltage circuit and the negative output terminal VOUT- of the output voltage circuit.

3. The large-capacity capacitor pre-charging circuit as described in claim 1, characterized in that, The relay circuit includes relay RELAY1 and relay RELAY2, which are connected in parallel.

4. The large-capacity capacitor pre-charging circuit as described in claim 1, characterized in that, The buffer circuit includes an output capacitor C1, an output capacitor C2, a transistor IGBT2, a pre-charge resistor R1, and a diode VD1. One end of the output capacitor C1 is connected to the positive output terminal VOUT+ of the output voltage circuit, and the other end of the output capacitor C1 is connected to the negative output terminal VOUT- of the output voltage circuit. The output capacitor C2 is connected in parallel with the output capacitor C1. The diode VD1, the transistor IGBT2, and the pre-charge resistor R1 are connected in series in sequence, and the diode VD1, the transistor IGBT2, and the pre-charge resistor R1 are connected in parallel across the two ends of the relay circuit. The anode of the diode VD1 is connected to the positive input terminal VIN+ of the input voltage circuit, and the cathode of the diode VD1 is connected to the transistor IGBT2.

5. The large-capacity capacitor pre-charging circuit as described in claim 1, characterized in that, The MCU control circuit includes an MCU, which is connected between the input voltage circuit and the output voltage circuit.

6. The large-capacity capacitor pre-charging circuit as described in claim 5, characterized in that, The MCU control circuit further includes a first optocoupler operation control circuit and a second optocoupler operation control circuit, both of which are connected to the MCU.

7. The large-capacity capacitor pre-charging circuit as described in claim 5, characterized in that, The MCU control circuit also includes an optocoupler output control circuit, which is connected to the MCU.

8. The large-capacity capacitor pre-charging circuit as described in claim 5, characterized in that, The pre-charging circuit also includes a communication circuit, which is connected to the MCU.

9. The large-capacity capacitor pre-charging circuit as described in claim 2, characterized in that, The pre-charging circuit also includes a filtering circuit, which includes a capacitor C3 and a common-mode inductor L1. One end of the capacitor C3 is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the capacitor C3 is connected to the negative input terminal VIN- of the input voltage circuit. One end of the common-mode inductor L1 is connected to the positive input terminal VIN+ of the input voltage circuit, and the other end of the common-mode inductor L1 is connected to the negative input terminal VIN- of the input voltage circuit.

10. The large-capacity capacitor pre-charging circuit as described in claim 9, characterized in that, The pre-charge circuit also includes a current detection circuit, which includes a current detection resistor R2 connected in series between the diode D1 and the common-mode inductor L1.

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