Voltage acquisition circuit and MSD anti-electric shock protection circuit

Abstract

The utility model belongs to the technical field of power supply systems, and specifically relates to a voltage acquisition circuit and an MSD anti-electric shock protection circuit. The MSD anti-electric shock protection circuit comprises an MSD and a voltage acquisition circuit, the MSD is used for being arranged between a power battery and a power battery access end accessed to a high-voltage power utilization assembly, the voltage acquisition circuit is used for being connected with the power battery through the MSD, and the MSD anti-electric shock protection circuit further comprises a switch module, the switch module is connected in series between a positive sampling end and / or a negative sampling end of the voltage acquisition circuit and a voltage division module of the voltage acquisition circuit, a control end of the switch module is controlled by a BMS power supply loop or an output end of a BMS control module, and the switch module is used for being disconnected after a BMS is powered off, so that after the MSD plug is separated from the base, the MSD plug is connected with the voltage division module of the voltage acquisition circuit. The two ends of the main contact of the MSD base do not have high voltage, the electric shock risk of maintenance personnel possibly caused by high-voltage electrification of the two ends of the main contact of the MSD base is avoided, and the safety of the whole vehicle is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of power supply systems, and particularly relates to a voltage acquisition circuit and an MSD electric shock protection circuit. Background Art

[0002] In order to ensure the safety of the battery during use and maintenance, an MSD (Manual Service Disconnect) is provided between the power battery and the high-voltage power-consuming components. The MSD is mainly used to ensure the safety of technicians repairing electric vehicles in a high-voltage environment or respond to emergencies. By disconnecting the MSD, the connection of the high-voltage circuit between the power battery and the high-voltage power-consuming components can be quickly separated, so that maintenance and other work are in a relatively safe state. In the prior art, the BMS (Battery Management System) detects the total voltage at multiple points of the power battery system through a voltage acquisition circuit to judge the state of the power battery, the open / closed state of the MSD, fuse or contactor, etc. When repairing after the vehicle is powered off, the maintenance personnel will separate the MSD plug from the base to disconnect the MSD. At this time, the contacts at both ends of the MSD base are exposed. Due to the influence of the voltage acquisition circuit, high voltage will be present at both ends of the main contacts of the MSD base. When the maintenance personnel accidentally touch the contacts at both ends of the MSD base, it will cause electric shock damage to the maintenance personnel, which is not conducive to the high-voltage safety of the vehicle. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a voltage acquisition circuit and an MSD electric shock protection circuit to solve the problem of electric shock risk caused by both ends of the MSD base during maintenance in the prior art.

[0004] The utility model provides an MSD electric shock protection circuit to solve the above technical problems. The circuit includes an MSD and a voltage acquisition circuit. The MSD is used to be arranged between the power battery and the power battery access end of the high-voltage power-consuming component connected. The voltage acquisition circuit is connected to the power battery through the MSD. The circuit further includes a switch module. The switch module is serially arranged between the positive sampling end and / or the negative sampling end of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit. The control end of the switch module is controlled by the BMS power supply circuit or the output end of the BMS control module. The switch module is used to disconnect after the BMS is powered off.

[0005] Further, the switch module is a MOSFET. The gate of the MOSFET is controlled by the output end of the BMS control module. The source and drain of the MOSFET are serially arranged between the positive sampling end and / or the negative sampling end of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0006] Further, the switch module is a triode, the base of the triode is controlled by the output end of the BMS control module, and the collector and emitter of the triode are serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0007] Further, the switch module is a relay, the relay includes a coil and a normally closed contact, the coil of the relay is connected in the BMS power supply loop or the loop where the output end of the BMS control module is located, and the normally closed contact of the relay is serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0008] Further, the switch module is serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0009] The beneficial effects of the above technical solution are as follows: The present utility model is an improved invention. By arranging a switch module between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit, and the switch module is controlled by the BMS power supply loop or the output end of the BMS control module. When the vehicle is being repaired and the whole vehicle is powered down at low voltage, the BMS is powered down, the power supply loop of the BMS is disconnected, and after the BMS control module senses that the BMS is powered down, the output end no longer outputs an enabling signal to control the switch module to conduct, and the switch module disconnects the connection between the voltage acquisition circuit and the MSD, and the voltage acquisition loop is completely open. Thus, after the MSD plug is separated from the base, the main contacts at both ends of the MSD base will not carry high voltage, avoiding the risk of electric shock to maintenance personnel that may be caused by the high voltage charged at both ends of the main contacts of the MSD base, and improving the safety of the whole vehicle.

[0010] To solve the above technical problems, the present utility model also provides a voltage acquisition circuit. The positive sampling terminal and the negative sampling terminal of the voltage acquisition circuit are respectively connected to the positive and negative electrodes of two power batteries, and further includes a switch module. The switch module is serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit, and the control end of the switch module is controlled by the BMS power supply loop or the output end of the BMS control module. The switch module is used to disconnect after the BMS is powered down.

[0011] Further, the switch module is a MOSFET, the gate of the MOSFET is controlled by the output end of the BMS control module, and the source and drain of the MOSFET are serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0012] Further, the switch module is a triode, the base of the triode is controlled by the output end of the BMS control module, and the collector and emitter of the triode are serially arranged between the positive sampling end and / or the negative sampling end of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0013] Further, the switch module is a relay, the relay includes a coil and a normally closed contact, the coil of the relay is connected in the BMS power supply circuit or the circuit where the output end of the BMS control module is located, and the normally closed contact of the relay is serially arranged between the positive sampling end and / or the negative sampling end of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0014] Further, the switch module is serially arranged between the positive sampling end and / or the negative sampling end of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit.

[0015] The beneficial effects of the above technical solution are as follows: The present utility model is an improved invention. By arranging a switch module between the positive sampling end and / or the negative sampling end of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit, and the switch module is controlled by the BMS power supply circuit or the output end of the BMS control module. When the vehicle is being repaired and the whole vehicle is powered down at low voltage, the BMS is powered down, the power supply circuit of the BMS is disconnected, and after the BMS control module senses that the BMS is powered down, the output end no longer outputs an enabling signal to control the switch module to conduct, and the switch module disconnects the connection between the voltage acquisition circuit and the MSD, and the voltage acquisition loop is completely open. Therefore, after the MSD plug is separated from the base, the main contacts at both ends of the MSD base will not carry high voltage, avoiding the risk of electric shock to maintenance personnel that may be caused by the high voltage charged at both ends of the main contacts of the MSD base, and improving the safety of the whole vehicle. Description of the Drawings

[0016] Figure 1 is the MSD anti-electric shock protection circuit diagram of the embodiment of the MSD anti-electric shock protection circuit of the present utility model. Detailed Embodiments

[0017] In order to make the purpose, technical solution and advantages of the present utility model clearer, the following further describes the detailed embodiments of the present utility model with reference to the drawings.

[0018] The utility model is an improved invention, in which a switch module is arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage collection circuit and the voltage dividing module of the voltage collection circuit, and the switch module is controlled by the BMS power supply circuit or the output terminal of the BMS control module. When the vehicle is repaired, the BMS is powered off after the whole vehicle is powered off at low voltage, the power supply circuit of the BMS is disconnected, and after the BMS control module senses that the BMS is powered off, the output terminal no longer outputs an enable signal for controlling the switch module to be turned on, and the control switch module disconnects the connection between the voltage collection circuit and the MSD, and the voltage collection circuit is completely disconnected, so that after the MSD plug is separated from the base, the two ends of the main contacts of the MSD base will not carry high voltage, thereby avoiding the risk of electric shock to maintenance personnel caused by the high voltage at the two ends of the main contacts of the MSD base, thereby improving the safety of the whole vehicle.

[0019] MSD anti-electric shock protection circuit embodiment

[0020] The utility model provides a MSD anti-electric shock protection circuit, such as Figure 1 As shown, it includes MSD and a voltage acquisition circuit, the MSD is a high-voltage MSD, and the MSD is arranged on the power battery ( Figure 1 The positive sampling terminal and / or negative sampling terminal of the voltage acquisition circuit are connected to the positive and negative electrodes of the two power batteries respectively. The voltage acquisition circuit includes a voltage divider module, a voltage acquisition isolation module, a signal conversion module and a switch module. The switch module is arranged in series between the positive input terminal and / or negative input terminal of the voltage acquisition circuit and the voltage divider module of the voltage acquisition circuit. The switch module is controlled by the BMS power supply circuit or the output terminal of the BMS control module. After the vehicle is powered off at low voltage, the BMS is powered off, the BMS power supply circuit is disconnected, and the output terminal of the BMS control module no longer outputs an enable signal. The switch module is controlled to disconnect the voltage acquisition circuit from the MSD, so that the voltage acquisition circuit and the high-voltage circuit are completely disconnected, making the power battery system safer when debugging or repairing when the MSD is disconnected.

[0021] Among them, the switch module is a controllable switch, including but not limited to MOSFET, triode, relay, etc. In one embodiment, the switch module is a MOSFET. The gate of the MOSFET is controlled by the output terminal of the BMS control module. The source and drain of the MOSFET are serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit. When the vehicle is not powered off at low voltage, the output terminal of the BMS control module outputs a normal level signal to control the MOSFET to conduct normally without affecting the sampling of the power battery or the high-voltage MSD. When the vehicle is powered off at low voltage, the output terminal of the BMS control module no longer outputs an enabling signal, and the MOSFET cannot conduct, and the voltage acquisition circuit is completely open, thereby disconnecting the connection with the high-voltage loop of the MSD.

[0022] In another embodiment, the switch module is a triode. The base of the triode is controlled by the output terminal of the BMS control module. The collector and emitter of the triode are serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit. When the vehicle is not powered off at low voltage, the output terminal of the BMS control module outputs a normal level signal to control the triode to conduct normally without affecting the sampling of the power battery or the high-voltage MSD. When the vehicle is powered off at low voltage, the BMS power supply circuit is disconnected and the output terminal of the BMS control module no longer outputs an enabling signal, and the triode cannot conduct, and the voltage acquisition circuit is completely open, thereby disconnecting the connection with the high-voltage loop of the MSD.

[0023] The switch module can also be a relay. The relay includes a coil and a normally closed contact. The coil of the relay is connected to the BMS power supply circuit or the circuit where the output terminal of the BMS control module is located. The normally closed contact of the relay is serially arranged between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage division module of the voltage acquisition circuit. When the vehicle is not powered off at low voltage, the voltage of the output terminal circuit of the BMS control module and the BMS power supply circuit is normal, the relay coil is normally energized, and the normally closed contact of the relay is closed without affecting the sampling of the power battery or the high-voltage MSD. When the vehicle is powered off at low voltage, the BMS power supply circuit is open and there is no power at the output terminal of the BMS control module, and the relay coil loses power, resulting in the disconnection of the normally closed contact of the relay, and the voltage acquisition circuit is completely open, thereby disconnecting the connection with the high-voltage loop of the MSD. The BMS control module is a single-chip microcomputer.

[0024] The voltage division module in the voltage sampling circuit includes voltage division resistors R25, R21, R18, and R20, which convert the collected high-voltage analog signal into a low-voltage analog signal through voltage division resistors; the acquisition isolation voltage module includes diode VD15, capacitors C6, C7, C10, and chip U5. By setting the acquisition isolation voltage module composed of the acquisition isolation voltage sensor U5, crosstalk between high- and low-voltage circuits can be effectively prevented; the signal conversion module includes amplifier U15, resistors R16, R29, R12, R33, R19, capacitors C12, C9, and C5. By setting the signal conversion module composed of an amplifier, the low-voltage analog signal can be converted into an analog voltage signal that can be received by the BMS single-chip microcomputer. The BMS single-chip microcomputer obtains the collected total battery voltage data through analog-to-digital conversion and parsing. Further, in order to keep the output port voltage within the range of VDD to GND, a bidirectional clamping circuit composed of clamping diodes is also provided.

[0025] Embodiment of the voltage acquisition circuit

[0026] The present utility model provides a voltage acquisition circuit. This voltage sampling circuit is a voltage acquisition circuit introduced in the above-mentioned embodiment of the MSD electric shock protection circuit, which will not be elaborated here.

Claims

1. An MSD anti-electric shock protection circuit, comprising an MSD and a voltage acquisition circuit, wherein the MSD is arranged between a power battery and a power battery access terminal connected to a high-voltage power component, and the voltage acquisition circuit is connected to the power battery through the MSD, characterized in that: It also includes a switch module, which is arranged in series between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage dividing module of the voltage acquisition circuit. The control end of the switch module is controlled by the BMS power supply circuit or the output end of the BMS control module. The switch module is used to disconnect after the BMS is powered off.

2. The MSD anti-electric shock protection circuit according to claim 1, characterized in that: The switch module is a MOSFET, the gate of the MOSFET is controlled by the output end of the BMS control module, and the source and drain of the MOSFET are arranged in series between the positive sampling end and / or the negative sampling end of the voltage collection circuit and the voltage divider module of the voltage collection circuit.

3. The MSD anti-electric shock protection circuit according to claim 1, characterized in that: The switch module is a triode, the base of which is controlled by the output end of the BMS control module, and the collector and emitter of the triode are arranged in series between the positive sampling end and / or the negative sampling end of the voltage collection circuit and the voltage divider module of the voltage collection circuit.

4. The MSD anti-electric shock protection circuit according to claim 1, characterized in that: The switch module is a relay, which includes a coil and a normally closed contact. The coil of the relay is connected to the BMS power supply circuit or the circuit where the output end of the BMS control module is located, and the normally closed contact of the relay is arranged in series between the positive sampling end and / or the negative sampling end of the voltage collection circuit and the voltage divider module of the voltage collection circuit.

5. A voltage collection circuit, wherein the positive sampling terminal and the negative sampling terminal of the voltage collection circuit are respectively connected to the positive electrode and the negative electrode of two power batteries, characterized in that: It also includes a switch module, which is arranged in series between the positive sampling terminal and / or the negative sampling terminal of the voltage acquisition circuit and the voltage dividing module of the voltage acquisition circuit. The control end of the switch module is controlled by the BMS power supply circuit or the output end of the BMS control module. The switch module is used to disconnect after the BMS is powered off.

6. The voltage acquisition circuit according to claim 5, characterized in that: The switch module is a MOSFET, the gate of the MOSFET is controlled by the output end of the BMS control module, and the source and drain of the MOSFET are arranged in series between the positive sampling end and / or the negative sampling end of the voltage collection circuit and the voltage divider module of the voltage collection circuit.

7. The voltage acquisition circuit according to claim 5, characterized in that: The switch module is a triode, the base of which is controlled by the output end of the BMS control module, and the collector and emitter of the triode are arranged in series between the positive sampling end and / or the negative sampling end of the voltage collection circuit and the voltage divider module of the voltage collection circuit.

8. The voltage acquisition circuit according to claim 5, characterized in that: The switch module is a relay, which includes a coil and a normally closed contact. The coil of the relay is connected to the BMS power supply circuit or the circuit where the output end of the BMS control module is located, and the normally closed contact of the relay is arranged in series between the positive sampling end and / or the negative sampling end of the voltage collection circuit and the voltage divider module of the voltage collection circuit.

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