High-voltage sampling system and method

Abstract

The invention discloses a high-voltage sampling system and method. The high-voltage sampling system comprises a switch control module, a voltage dividing module, a first monitoring module, a high-voltage sampling module and a main control module, in the voltage dividing module, a first-stage voltage dividing unit is electrically connected with a high-voltage bus through a switch control module; the second-stage voltage dividing unit and the first-stage voltage dividing unit are electrically connected to a first voltage dividing node; the third-stage voltage dividing unit and the second-stage voltage dividing unit are electrically connected to a second voltage dividing node; the first monitoring module is used for monitoring the voltage of the first voltage dividing node, controlling the switch control module to be switched off when the voltage of the first voltage dividing node is abnormal, and providing a first feedback signal for the main control module; the high-voltage sampling module is used for collecting the voltage of the second voltage dividing node and providing a high-voltage sampling signal for the main control module; and the main control module is used for controlling the switch control module to be switched off according to the first feedback signal when the voltage of the first voltage division node is abnormal. By adopting the technical scheme, the safety and the reliability of the high-voltage sampling system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicle power batteries, and in particular to a high-voltage sampling system and method. Background Art

[0002] In the inverter drive system of new energy vehicles, detecting the high voltage of the power battery busbar is a critical functional requirement. Its core purpose is to accurately identify the high voltage state of the power battery, thereby ensuring the reliable operation of the inverter drive system. To ensure the safety of the detection process, the high-voltage voltage sampling circuit is designed as an isolated sampling circuit, thereby achieving the safe application of the low-voltage side sampling circuit.

[0003] Currently, the isolated sampling solutions adopted by the industry still require the high-voltage circuit and reference ground to be physically connected through the circuit board PCB. Such solutions usually rely on a multi-stage resistor divider network in conjunction with an isolated operational amplifier to complete the conversion and sampling of high-voltage signals to low-voltage signals. However, this sampling method has the risk of resistance component failure. If the AD sampling strategy of the digital logic processing module software is relied upon alone, it cannot meet the requirements of functional safety design and cannot effectively guarantee the reliability of the inverter bus high-voltage acquisition circuit. Once the sampling circuit fails, it may cause unpredictable safety hazards and even pose a threat to personal safety. Some solutions reduce the risk by increasing the sampling series resistor. Although this reduces the probability of failure to a certain extent, it cannot avoid the common cause failure problem caused by the same inducement. In summary, the existing power battery bus high-voltage monitoring technology still has significant deficiencies in reliability. Summary of the Invention

[0004] The embodiments of the present invention provide a high-voltage sampling system and method, which construct a dual protection mechanism of a first monitoring module and a main control module, thereby improving the safety and reliability of the high-voltage sampling system.

[0005] According to one aspect of the present invention, a high-voltage sampling system is provided, comprising: a switch control module, a voltage dividing module, a first monitoring module, a high-voltage sampling module and a main control module;

[0006] The voltage divider module includes a primary voltage divider unit, a secondary voltage divider unit and a tertiary voltage divider unit; the primary voltage divider unit is electrically connected to the high-voltage bus through the switch control module; the secondary voltage divider unit and the primary voltage divider unit are electrically connected to a first voltage divider node; the tertiary voltage divider unit and the secondary voltage divider unit are electrically connected to a second voltage divider node;

[0007] The first monitoring module is electrically connected to the first voltage-dividing node, the switch control module, and the main control module, respectively; the first monitoring module is used to monitor the voltage of the first voltage-dividing node, and when the voltage of the first voltage-dividing node is abnormal, control the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage-dividing unit, and provide a first feedback signal to the main control module;

[0008] The high-voltage sampling module is electrically connected to the second voltage-dividing node and the main control module respectively; the high-voltage sampling module is used to collect the voltage of the second voltage-dividing node and provide a high-voltage sampling signal to the main control module;

[0009] The main control module is also electrically connected to the switch control module; the main control module is used to control the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage divider unit according to the first feedback signal when the voltage of the first voltage divider node is abnormal.

[0010] Optionally, the switch control module includes a trigger and a relay;

[0011] The input end of the relay is electrically connected to the high-voltage bus; the output end of the relay is electrically connected to the first-level voltage divider unit; the first control end of the relay is electrically connected to the output end of the trigger; the first control end of the trigger is electrically connected to the first monitoring module; and the second control end of the trigger is electrically connected to the main control module.

[0012] Optionally, the first monitoring module includes a first branch resistor, a second branch resistor, an N-type MOS transistor and an optocoupler isolation switch;

[0013] The gate of the N-type MOS transistor is electrically connected to the first voltage dividing node; the first electrode of the N-type MOS transistor is electrically connected to the first voltage dividing node through the first branch resistor; the second electrode of the N-type MOS transistor is electrically connected to the anode pin of the light-emitting diode of the optocoupler isolation switch, and the cathode pin of the light-emitting diode is grounded through the second branch resistor; the cathode pin of the light-emitting diode is also electrically connected to the main control module;

[0014] The input pin of the optocoupler isolating switch is connected to the low-voltage power supply end; the output pin of the optocoupler isolating switch is electrically connected to the switch control module.

[0015] Optionally, the first monitoring module further includes a third branch resistor and a fourth branch resistor;

[0016] The gate of the N-type MOS transistor and the first branch resistor are both electrically connected to the first voltage dividing node through the third branch resistor;

[0017] The gate of the N-type MOS transistor is also grounded through the fourth branch resistor.

[0018] Optionally, the first monitoring module further includes a voltage stabilizing diode;

[0019] The cathode of the voltage stabilizing diode is electrically connected to the gate of the N-type MOS tube; the anode of the voltage stabilizing diode is grounded.

[0020] Optionally, the first monitoring module further includes a first detection unit;

[0021] The first detection unit includes a differential amplifier and a comparator;

[0022] The first input terminal of the differential amplifier is electrically connected to the cathode pin, the second input terminal of the differential amplifier is grounded, the output terminal of the differential amplifier is electrically connected to the first input terminal of the comparator, the second input terminal of the comparator receives a reference threshold, and the output terminal of the comparator is electrically connected to the main control module.

[0023] Optionally, the high-voltage sampling system further includes a first current-limiting resistor, a series blocking surge protector, and a second monitoring module;

[0024] The high-voltage sampling module is electrically connected to the second voltage dividing node through the first current limiting resistor and the series blocking surge protector;

[0025] The second monitoring module is electrically connected to the second voltage dividing node through the first current limiting resistor and / or the series blocking surge protector; the second monitoring module is used to monitor the voltage of the second voltage dividing node and provide a second feedback signal to the main control module when the voltage of the second voltage dividing node is abnormal.

[0026] Optionally, the second monitoring module includes a second detection unit;

[0027] The second detection unit includes a filter circuit, a differential amplifier, and a follower circuit;

[0028] The first input end of the differential amplifier is electrically connected to the connection node between the first current limiting resistor and the series blocking surge protector through the filter circuit; the second input end of the differential amplifier is electrically connected to the second voltage dividing node through the filter circuit, or the second input end of the differential amplifier is electrically connected to the input end of the high-voltage sampling module through the filter circuit;

[0029] The output end of the differential amplifier is electrically connected to the main control module through the follower circuit.

[0030] According to another aspect of the present invention, a high-voltage sampling method for a high-voltage bus is provided, comprising the high-voltage sampling system for a high-voltage bus described in any one of the above items;

[0031] The high-voltage sampling method comprises:

[0032] Obtaining a first feedback signal output by the first monitoring module;

[0033] determining, according to the first feedback signal, whether the voltage of the first voltage-dividing node is abnormal;

[0034] When the voltage of the first voltage dividing node is abnormal, controlling the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage dividing unit;

[0035] When the voltage of the first voltage-dividing node is normal, the high-voltage sampling signal output by the high-voltage sampling module is obtained to complete the high-voltage sampling task of the high-voltage bus.

[0036] Optionally, the high-voltage sampling system further includes a first current limiting resistor, a series blocking surge protector, and a second monitoring module; the high-voltage sampling module is electrically connected to the second voltage dividing node through the first current limiting resistor and the series blocking surge protector; the second monitoring module is electrically connected to the second voltage dividing node through the first current limiting resistor and / or the series blocking surge protector; the second monitoring module is used to monitor the voltage of the second voltage dividing node and provide a second feedback signal to the main control module when the voltage of the second voltage dividing node is abnormal;

[0037] Obtaining the high-voltage sampling signal output by the high-voltage sampling module to complete the high-voltage sampling task of the high-voltage bus includes:

[0038] Obtaining a second feedback signal output by the second monitoring module;

[0039] determining, according to the second feedback signal, whether the voltage of the second voltage-dividing node is abnormal;

[0040] When the voltage of the second voltage dividing node is abnormal, controlling the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage dividing unit;

[0041] When the voltage of the second voltage-dividing node is normal, the high-voltage sampling signal output by the high-voltage sampling module is obtained to complete the high-voltage sampling task of the high-voltage bus.

[0042] The technical solution of the present invention is to set a switch control module to connect the bus and the voltage divider module. The voltage divider module can reduce the high voltage of the bus to a safe range. The first monitoring module monitors the voltage of the first voltage divider node in real time, and shuts down the switch control module and feeds back to the main control module when the voltage of the first voltage divider node is abnormal; the high-voltage sampling module can collect the voltage of the second voltage divider node and provide a sampling signal to the main control module; the main control module integrates the feedback signal and the sampling signal to control the switch control module to perform a power-off operation, ensuring the safe and reliable operation of the high-voltage sampling system. This system realizes the graded voltage reduction of the high-voltage bus, improves the voltage resistance of the circuit, effectively avoids the failure risk caused by the breakdown short circuit of the voltage divider resistor in the traditional high-voltage sampling system, constructs a dual protection mechanism of the first monitoring module and the main control module, and improves the safety and reliability of the high-voltage sampling system.

[0043] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 This is a circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention;

[0046] Figure 2 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention;

[0047] Figure 3 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention;

[0048] Figure 4 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention;

[0049] Figure 5 is a structural diagram of a first detection unit provided by an embodiment of the present invention;

[0050] Figure 6 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention;

[0051] Figure 7 is a structural schematic diagram of a second detection unit provided by an embodiment of the present invention;

[0052] Figure 8 This is a flow chart of a high-voltage sampling method provided by an embodiment of the present invention;

[0053] Figure 9 This is a flow chart of another high-voltage sampling method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] Figure 1 This is a circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention, referring to Figure 1 The high-voltage sampling system includes: a switch control module 10 , a voltage dividing module 20 , a first monitoring module 30 , a high-voltage sampling module 40 and a main control module 50 .

[0057] The voltage dividing module 20 includes a primary voltage dividing unit 21, a secondary voltage dividing unit 22 and a tertiary voltage dividing unit 23; the primary voltage dividing unit 21 is electrically connected to the high-voltage bus 01 through the switch control module 10; the secondary voltage dividing unit 22 and the primary voltage dividing unit 21 are electrically connected to the first voltage dividing node N1; the tertiary voltage dividing unit 23 and the secondary voltage dividing unit 22 are electrically connected to the second voltage dividing node N2.

[0058] The first monitoring module 30 is electrically connected to the first voltage-dividing node N1, the switch control module 10 and the main control module 50 respectively; the first monitoring module 30 is used to monitor the voltage of the first voltage-dividing node N1, and when the voltage of the first voltage-dividing node N1 is abnormal, control the switch control module 10 to disconnect the connection path between the high-voltage bus 01 and the primary voltage-dividing unit 21, and provide a first feedback signal to the main control module 50.

[0059] The high-voltage sampling module 40 is electrically connected to the second voltage-dividing node and the main control module 50 , respectively. The high-voltage sampling module 40 is used to collect the voltage of the second voltage-dividing node and provide a high-voltage sampling signal to the main control module 50 .

[0060] The main control module 50 is also electrically connected to the switch control module 10; the main control module 50 is used to control the switch control module 10 to disconnect the connection path between the high-voltage bus 01 and the first-level voltage dividing unit 21 according to the first feedback signal when the voltage at the first voltage dividing node is abnormal.

[0061] Among them, the high-voltage bus 01 can be the output bus of the power battery PACK of the new energy vehicle.

[0062] When the switch control module 10 detects an anomaly in the high-voltage sampling system, it can be quickly disconnected, interrupting the connection between the high-voltage bus 01 and the high-voltage sampling system. This prevents the anomaly from causing excessive internal node potentials, potentially damaging circuit boards or endangering safety. The voltage divider module 20 uses multiple voltage divider units to reduce the high-voltage potential of the high-voltage bus 01 to a safe range, facilitating subsequent safe sampling by the high-voltage sampling module 40.

[0063] The first-level voltage divider unit 21 is electrically connected to the high-voltage bus 01 through the switch control module 10. The voltage of the high-voltage bus 01 is very high, and the first-level voltage divider unit 21 is subjected to the greatest electrical stress. If the resistor of the first-level voltage divider unit 21 is broken down and short-circuited, the high voltage will directly flow into the subsequent circuit. Therefore, the first-level voltage divider unit 21 usually uses a resistor (R1) with high withstand voltage and low failure probability to play a major role in reducing voltage. The second-level voltage divider unit 22 is composed of multiple resistors (R21,..., R2n, n is an integer greater than 1) in series. The voltage can be shared by the resistors in series, reducing the withstand voltage of a single resistor and avoiding breakdown by high voltage. At the same time, multiple resistors can disperse the risk of failure. Even if a resistor fails, other resistors can still maintain the operation of the voltage divider circuit. The third-level voltage divider unit 23 includes at least one resistor (R03) to further reduce the voltage to a low voltage suitable for sampling, ensuring the accuracy of the sampled data and the safety of the subsequent circuit.

[0064] The first monitoring module 30 can monitor the voltage after being divided by the first-level voltage divider unit 21, thereby monitoring whether the first-level voltage divider unit 21 is normal. When the first-level voltage divider unit 21 is short-circuited, the voltage of the first voltage divider node N1 rises rapidly, far exceeding the normal threshold value. At this time, the first monitoring module 30 controls the switch control module 10 to perform hardware shutdown on the connection path between the high-voltage bus 01 and the first-level voltage divider unit 21, which can prevent the high-voltage signal of the high-voltage bus from directly entering the internal circuit of the high-voltage sampling system through the short-circuited first-level voltage divider unit 21, causing the PCB board where the high-voltage sampling system is located to be burned; at the same time, the first monitoring module 30 can also provide a first feedback signal to the main control module 50, and feedback to the main control module 50 whether the voltage of the first voltage divider node N1 is abnormal. In an optional embodiment, the first feedback signal can be a high-level signal.

[0065] The high-voltage sampling module 40 is electrically connected to the second voltage-dividing node N2 and the main control module 50, respectively. The high-voltage sampling module 40 can achieve precise sampling while ensuring electrical safety through an isolation op amp. This isolates the voltage-dividing module 20 from the main control module 50 on the low-voltage side, preventing high voltage from entering and burning the main control module 50 in the event of a voltage-dividing module 20 failure. For example, the high-voltage sampling module 40 can process and convert the voltage signal at the second voltage-dividing node N2 into a digital signal, ensuring sampling accuracy to support real-time sampling of the bus voltage while also enabling fault detection based on changes in sampling results when the voltage-dividing circuit is abnormal.

[0066] The main control module 50 is based on the MCU microcontroller unit and can receive feedback signals and send control signals to ensure that the high-voltage sampling system can operate safely under various working conditions. When the voltage of the first voltage-dividing node N1 is abnormal, the first monitoring module 30 controls the switch control module 10 to cut off the connection between the high-voltage bus and the first voltage-dividing unit 21, and at the same time sends a first feedback signal to the main control module 50. After the main control module 50 receives the abnormal signal fed back by the first monitoring module 30, it can further confirm the fault type through software logic and directly send a control instruction to the switch control module 10 to disconnect the connection path between the high-voltage bus and the first voltage-dividing unit 21, ensuring that the connection between the high-voltage bus 01 and the high-voltage sampling system is completely cut off. This prevents the first monitoring module 30 from mistakenly judging that the voltage of the first voltage-dividing node N1 is normal after shutting off the connection path between the high-voltage bus 01 and the first voltage-dividing unit 21 through the switch control module 10, causing the voltage of the first voltage-dividing node N1 to decrease, and repeatedly turning on and off the switch control module 10, resulting in repeated opening and closing of the internal components of the first monitoring module 30 and the switch control module 10.

[0067] The high-voltage busbar high-voltage sampling system proposed in the embodiment of the present invention is provided with a switch control module connecting the busbar and the voltage divider module. The voltage divider module can reduce the high voltage of the busbar to a safe range. The first monitoring module monitors the voltage of the first voltage divider node in real time, and shuts down the switch control module and feeds back to the main control module when the voltage of the first voltage divider node is abnormal; the high-voltage sampling module can collect the voltage of the second voltage divider node and provide a sampling signal to the main control module; the main control module integrates the feedback signal and the sampling signal, controls the switch control module to perform a power-off operation, and ensures the safe and reliable operation of the high-voltage sampling system. This system realizes the graded voltage reduction of the high-voltage busbar, improves the voltage resistance of the protection circuit, effectively avoids the failure risk caused by the breakdown and short circuit of the voltage divider resistor in the traditional high-voltage sampling system, constructs a dual protection mechanism of the first monitoring module and the main control module, and improves the safety and reliability of the high-voltage sampling system.

[0068] Optional, Figure 2 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention, referring to Figure 2 The switch control module 10 includes a trigger 11 and a relay 12; the input end of the relay 12 is electrically connected to the high-voltage bus 01; the output end of the relay 12 is electrically connected to the first-level voltage divider unit 21; the first control end of the relay 12 is electrically connected to the output end of the trigger 11; the first control end of the trigger 11 is electrically connected to the first monitoring module 30; and the second control end of the trigger 11 is electrically connected to the main control module 50.

[0069] Exemplarily, the first control terminal of the trigger 11 is electrically connected to the first monitoring module 30. When the primary voltage divider unit 21 short-circuits, causing the voltage at the first voltage divider node N1 to abnormally increase, the first monitoring module 30 can control the potential of the output terminal of the trigger 11 to flip, energizing the coil of the relay 12 and instantly disconnecting the contacts, thereby achieving an emergency shutdown between the high-voltage bus 01 and the primary voltage divider unit 21. The second control terminal of the trigger 11 is electrically connected to the main control module 50. When the main control module 50 receives fault feedback, it sends a control signal to the trigger 11 through software instructions to ensure that the relay 12 is continuously disconnected, thereby preventing the first monitoring module 30 from mistakenly determining that the voltage at the first voltage divider node N1 is normal after the switch control module 10 is turned off, and controlling the relay 12 to conduct through the trigger 11, resulting in repeated opening and closing of the internal components of the first monitoring module 30 and the switch control module 10. The trigger 11 of the switch control module 10 can control the relay 12 to be turned off under the dual control mechanism of hardware shutdown of the first monitoring module 30 and software shutdown of the main control module, significantly improving the safety and reliability of the high-voltage sampling system.

[0070] Optional, continue to refer to Figure 2The first monitoring module 30 includes a first branch resistor R31, a second branch resistor R32, an N-type MOS transistor M3, and an optocoupler isolation switch U3; the gate of the N-type MOS transistor 33 is electrically connected to the first voltage dividing node N1; the first electrode of the N-type MOS transistor 33 is electrically connected to the first voltage dividing node N1 through the first branch resistor R31; the second electrode of the N-type MOS transistor M3 is electrically connected to the anode pin of the light-emitting diode D1 of the optocoupler isolation switch 34, and the cathode pin of the light-emitting diode D1 is grounded through the second branch resistor R32; the cathode pin of the light-emitting diode 341 is also electrically connected to the main control module 50; the input pin of the optocoupler isolation switch 34 is connected to the low-voltage power supply terminal VCC; and the output pin of the optocoupler isolation switch 34 is electrically connected to the switch control module 10.

[0071] Exemplarily, the gate of the N-type MOS transistor M3 can be electrically connected to the first voltage-dividing node N1, and the voltage of the first voltage-dividing node N1 can be monitored in real time, thereby monitoring the state of the first voltage-dividing unit 21. When the first voltage-dividing unit 21 is short-circuited, causing the voltage of the first voltage-dividing node N1 to exceed the turn-on threshold of the N-type MOS transistor M3, the N-type MOS transistor M3 is turned on. In an optional embodiment, the turn-on threshold of the N-type MOS transistor 33 can be 5V. At this time, the current forms a loop through the first branch resistor 31, the N-type MOS transistor 33, the light-emitting diode D1, and the second branch resistor 32. The cathode pin of the light-emitting diode D1 is at a high level, sending a high-level signal to the switch control module 10, driving the relay 12 to turn off through the trigger 11. The optocoupler isolation switch 34 in the first monitoring module 30 completely isolates the high-voltage side from the low-voltage side of the circuit, ensuring the safety of the trigger 11. The cathode pin of LED 341 is electrically connected to the main control module 50. When the primary voltage divider unit 21 experiences a short circuit, the cathode pin of LED D1 goes high, sending a high-level signal to the main control module 50 and triggering the software protection strategy. Furthermore, the first branch resistor 31 limits the conduction current of N-type MOS transistor 33 to prevent device damage. The second branch resistor 32, connected in series with LED 341, ensures that it operates within a safe current range, protecting core components and optimizing circuit performance.

[0072] Optional, Figure 3 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention, referring to Figure 3 The first monitoring module 30 further includes a third branch resistor R33 and a fourth branch resistor R34; the gate of the N-type MOS transistor 33 and the first branch resistor 31 are both electrically connected to the first voltage dividing node N1 through the third branch resistor R33; the gate of the N-type MOS transistor 33 is also grounded through the fourth branch resistor R34.

[0073] It is understandable that further voltage division can be achieved by constructing a voltage division loop of the third branch resistor 35 and the fourth branch resistor 36 to prevent the gate of the N-type MOS tube 33 from being broken down. Therefore, the N-type MOS tube 33 can be set as a low-power NMOS to save cost and space.

[0074] Optional, continue to refer to Figure 3 The first monitoring module 30 further includes a voltage stabilizing diode DZ; the cathode of the voltage stabilizing diode DZ is electrically connected to the gate of the N-type MOS transistor M3; and the anode of the voltage stabilizing diode 37 is grounded.

[0075] Among them, the Zener diode 37 can serve as a voltage threshold setting element for the gate of the N-type MOS transistor 33 in the first monitoring module 30. The turn-on condition of the N-type MOS transistor 33 is controlled by its 5V regulated voltage value. When the voltage of the first voltage-dividing node N1 increases abnormally, the gate voltage after the voltage is divided by the third branch resistor R3 and the fourth branch resistor R4 exceeds the breakdown voltage of the Zener diode DZ. At this time, the Zener diode DZ breaks down in the reverse direction and turns on, maintaining the voltage stability of the gate of the N-type MOS transistor 33 and preventing the gate of the N-type MOS transistor 33 from being subjected to excessive voltage and breakdown.

[0076] Optional, Figure 4 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention, referring to Figure 4 The first monitoring module 30 further includes a first detection unit 38, Figure 5 This is a schematic diagram of the structure of a first detection unit provided by an embodiment of the present invention, with reference to Figure 4 and Figure 5 The first detection unit 38 includes a differential amplifier 381 and a comparator 382; a first input terminal of the differential amplifier 381 is electrically connected to the cathode pin of the light-emitting diode D1, a second input terminal of the differential amplifier 381 is grounded, an output terminal of the differential amplifier 381 is electrically connected to a first input terminal of the comparator 382, ​​a second input terminal of the comparator 382 receives a reference threshold, and an output terminal of the comparator 382 is electrically connected to the main control module 50.

[0077] For example, the first detection unit 38 can detect the voltage difference across the second branch resistor R32 through the differential amplifier 381 and the comparator 382, ​​and compare it with the reference threshold value to verify whether current is flowing in the second branch resistor R32, thereby outputting a first feedback signal to the main control module 50. When the voltage at the first voltage divider node N1 is abnormal, current is flowing in the second branch resistor R32, the voltage difference detected by the differential amplifier 381 exceeds the reference threshold value, and the comparator 382 outputs a digital signal of logic level 1, indicating that current is flowing in the second branch resistor R32 and the voltage at the first voltage divider node N1 is abnormal. Conversely, the comparator 382 outputs a digital signal of logic level 0, indicating that no current is flowing in the second branch resistor R32 and the voltage at the first voltage divider node N1 is normal, thereby monitoring whether the primary voltage divider unit 21 is normal and providing feedback to the main control module 50.

[0078] Optional, Figure 6 This is another circuit diagram of a high-voltage sampling system provided by an embodiment of the present invention, referring to Figure 6 The high-voltage sampling system also includes a first current limiting resistor R6, a series blocking surge protector F1 and a second monitoring module 80; the high-voltage sampling module 40 is electrically connected to the second voltage dividing node N2 through the first current limiting resistor R6 and the series blocking surge protector F1; the second monitoring module 80 is electrically connected to the second voltage dividing node N2 through the first current limiting resistor R6 and / or the series blocking surge protector F1; the second monitoring module 80 is used to monitor the voltage of the second voltage dividing node N2, and provide a second feedback signal to the main control module 50 when the voltage of the second voltage dividing node N2 is abnormal.

[0079] Among them, when the first-level voltage divider unit 21 and / or the second-level voltage divider unit 22 is short-circuited, the first current limiting resistor R6 can be used to limit the current flowing into the subsequent circuit to avoid burning the device. At the same time, the first current limiting resistor R6 and the third-level voltage divider unit 33 form a secondary voltage divider to improve the sampling accuracy. The series blocking surge protector F1 is an overvoltage protection device connected to the circuit in series. For example, the series blocking surge protector F1 generally includes a main path connecting the second voltage divider node N2 and the high-voltage sampling module 40 and a grounded bypass path (not shown in the figure). Its core feature is that under normal operating conditions, the bypass path is high impedance and the main path allows normal operating current to pass through; when a transient surge voltage exceeding the threshold appears in the circuit, the device is quickly triggered to turn on, the bypass path is converted to a low impedance state for discharge, and the main path blocks or limits the surge current, thereby protecting the subsequent circuit from damage. The second monitoring module 80 is used to monitor the voltage at the second voltage-dividing node. When the secondary voltage-dividing unit 22 fails (the multiple resistors within it are too large or too small, or there is a short circuit or open circuit), the voltage at the second voltage-dividing node N1 is too high or too low, and the current through the first current-limiting resistor 60 is also too high or too low. The second monitoring module 80 can monitor the current flowing through the first current-limiting resistor 60 and provide a second feedback signal to the main control module 50. In an optional embodiment, the second feedback signal is an analog signal that can indicate that the voltage at the second voltage-dividing node is too low or that the series blocking surge protector 70 has failed. When the voltage at the first voltage-dividing node N1 is normal, the second feedback signal is a moderate analog signal.

[0080] Optional, Figure 7 This is a schematic diagram of the structure of a second detection unit provided by an embodiment of the present invention, with reference to Figure 6 and Figure 7 The second monitoring module 80 includes a second detection unit 81; the second detection unit 81 includes a filter circuit 801, a differential amplifier 802, and a follower circuit 803; the first input end of the differential amplifier 802 is electrically connected to the connection node between the first current limiting resistor 60 and the series blocking surge protector 70 through the filter circuit 801; the second input end of the differential amplifier 802 is electrically connected to the second voltage dividing node N2 through the filter circuit 801, or the second input end of the differential amplifier 802 is electrically connected to the input end of the high-voltage sampling module 40 through the filter circuit 801; the output end of the differential amplifier 802 is electrically connected to the main control module 50 through the follower circuit 803.

[0081] Among them, the second detection unit 81 monitors the voltage value at both ends of the series blocking surge protector F1 or the voltage value at both ends of the first current limiting resistor R6 through the differential amplifier 802, and judges whether the current flowing through the first current limiting resistor 60 is too large or too small by comparing the voltage difference. At the same time, the follower circuit is used to realize signal buffering, isolation and impedance matching, and improve the load capacity, and utilize its high input impedance and low output impedance characteristics to ensure that the signal is stably transmitted to the main control module 50.

[0082] Figure 8 This is a flow chart of a high-voltage sampling method provided by an embodiment of the present invention. The high-voltage sampling method provided by an embodiment of the present invention can be applied to the high-voltage sampling system provided by any embodiment of the present invention. Figure 8 , high voltage sampling methods include:

[0083] S110: Obtain a first feedback signal output by a first monitoring module.

[0084] S120 : Determine whether the voltage of the first voltage-dividing node is abnormal according to the first feedback signal.

[0085] S130 : When the voltage at the first voltage dividing node is abnormal, control the switch control module to disconnect the connection path between the high-voltage bus and the first-level voltage dividing unit.

[0086] S140 . When the voltage at the first voltage-dividing node is normal, obtain a high-voltage sampling signal output by the high-voltage sampling module to complete the high-voltage sampling task of the high-voltage bus.

[0087] A high-voltage sampling method proposed in an embodiment of the present invention utilizes a first monitoring module to monitor the voltage of a first voltage-dividing node. When the voltage of the first voltage-dividing node is abnormal, the switch control module is controlled to disconnect the connection path between the high-voltage bus and the first-level voltage-dividing unit, thereby realizing the first-level high-voltage sampling protection. When the voltage of the first voltage-dividing node is normal, the high-voltage sampling signal output by the high-voltage sampling module is obtained to complete the high-voltage sampling task of the high-voltage bus. In this way, safety and reliability can be improved, and accurate sampling results can be obtained.

[0088] Optionally, the high-voltage sampling system also includes a first current limiting resistor R6, a series blocking surge protector F1 and a second monitoring module 80; the high-voltage sampling module 40 is electrically connected to the second voltage dividing node N2 through the first current limiting resistor R6 and the series blocking surge protector F1; the second monitoring module 80 is electrically connected to the second voltage dividing node N2 through the first current limiting resistor R6 and / or the series blocking surge protector F1; the second monitoring module 80 is used to monitor the voltage of the second voltage dividing node N2, and when the voltage of the second voltage dividing node N2 is abnormal, provide a second feedback signal to the main control module 50. Figure 9 This is another high-voltage sampling method flow chart provided by an embodiment of the present invention, refer to Figure 9, obtain the high-voltage sampling signal output by the high-voltage sampling module and complete the high-voltage sampling task of the high-voltage bus, including:

[0089] S141. Obtain a second feedback signal output by a second monitoring module.

[0090] S142: Determine whether the voltage of the second voltage-dividing node is abnormal according to the second feedback signal.

[0091] S143 . When the voltage at the second voltage dividing node is abnormal, control the switch control module to disconnect the connection path between the high voltage bus and the first-level voltage dividing unit.

[0092] S144. When the voltage at the second voltage-dividing node is normal, obtain the high-voltage sampling signal output by the high-voltage sampling module to complete the high-voltage sampling task of the high-voltage bus.

[0093] Another high-voltage sampling method proposed in an embodiment of the present invention utilizes a second monitoring module to detect the voltage of a second voltage-dividing node. When the voltage of the second voltage-dividing node is abnormal, the switch control module is controlled to disconnect the connection path between the high-voltage bus and the first-level voltage-dividing unit, thereby realizing the second-level high-voltage sampling protection. When the voltage of the second voltage-dividing node is normal, the high-voltage sampling signal output by the high-voltage sampling module is obtained to complete the high-voltage sampling task of the high-voltage bus, which is conducive to improving safety and reliability and obtaining accurate sampling results.

[0094] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A high-voltage sampling system, characterized in that: include: Switch control module, voltage dividing module, first monitoring module, high voltage sampling module and main control module; The voltage divider module includes a primary voltage divider unit, a secondary voltage divider unit and a tertiary voltage divider unit; the primary voltage divider unit is electrically connected to the high-voltage bus through the switch control module; the secondary voltage divider unit and the primary voltage divider unit are electrically connected to a first voltage divider node; the tertiary voltage divider unit and the secondary voltage divider unit are electrically connected to a second voltage divider node; The first monitoring module is electrically connected to the first voltage-dividing node, the switch control module, and the main control module, respectively; the first monitoring module is used to monitor the voltage of the first voltage-dividing node, and when the voltage of the first voltage-dividing node is abnormal, control the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage-dividing unit, and provide a first feedback signal to the main control module; The high-voltage sampling module is electrically connected to the second voltage-dividing node and the main control module respectively; the high-voltage sampling module is used to collect the voltage of the second voltage-dividing node and provide a high-voltage sampling signal to the main control module; The main control module is also electrically connected to the switch control module; the main control module is used to control the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage divider unit according to the first feedback signal when the voltage of the first voltage divider node is abnormal.

2. The high-voltage sampling system according to claim 1, characterized in that: The switch control module includes a trigger and a relay; The input end of the relay is electrically connected to the high-voltage bus; the output end of the relay is electrically connected to the first-level voltage divider unit; the first control end of the relay is electrically connected to the output end of the trigger; the first control end of the trigger is electrically connected to the first monitoring module; and the second control end of the trigger is electrically connected to the main control module.

3. The high-voltage sampling system according to claim 1, characterized in that: The first monitoring module includes a first branch resistor, a second branch resistor, an N-type MOS transistor and an optocoupler isolation switch; The gate of the N-type MOS transistor is electrically connected to the first voltage dividing node; the first electrode of the N-type MOS transistor is electrically connected to the first voltage dividing node through the first branch resistor; the second electrode of the N-type MOS transistor is electrically connected to the anode pin of the light-emitting diode of the optocoupler isolation switch, and the cathode pin of the light-emitting diode is grounded through the second branch resistor; the cathode pin of the light-emitting diode is also electrically connected to the main control module; The input pin of the optocoupler isolating switch is connected to the low-voltage power supply end; the output pin of the optocoupler isolating switch is electrically connected to the switch control module.

4. The high-voltage sampling system according to claim 3, characterized in that: The first monitoring module further includes a third branch resistor and a fourth branch resistor; The gate of the N-type MOS transistor and the first branch resistor are both electrically connected to the first voltage dividing node through the third branch resistor; The gate of the N-type MOS transistor is also grounded through the fourth branch resistor.

5. The high-voltage sampling system according to claim 3, characterized in that: The first monitoring module further includes a voltage stabilizing diode; The cathode of the voltage stabilizing diode is electrically connected to the gate of the N-type MOS tube; and the anode of the voltage stabilizing diode is grounded.

6. The high-voltage sampling system according to claim 3, characterized in that: The first monitoring module further includes a first detection unit; The first detection unit includes a differential amplifier and a comparator; The first input terminal of the differential amplifier is electrically connected to the cathode pin, the second input terminal of the differential amplifier is grounded, the output terminal of the differential amplifier is electrically connected to the first input terminal of the comparator, the second input terminal of the comparator receives a reference threshold, and the output terminal of the comparator is electrically connected to the main control module.

7. The high-voltage sampling system according to claim 1, characterized in that: The high-voltage sampling system further includes a first current-limiting resistor, a series blocking surge protector, and a second monitoring module; The high-voltage sampling module is electrically connected to the second voltage dividing node through the first current limiting resistor and the series blocking surge protector; The second monitoring module is electrically connected to the second voltage dividing node through the first current limiting resistor and / or the series blocking surge protector; the second monitoring module is used to monitor the voltage of the second voltage dividing node and provide a second feedback signal to the main control module when the voltage of the second voltage dividing node is abnormal.

8. The high-voltage sampling system according to claim 7, characterized in that: The second monitoring module includes a second detection unit; The second detection unit includes a filter circuit, a differential amplifier, and a follower circuit; The first input end of the differential amplifier is electrically connected to the connection node between the first current limiting resistor and the series blocking surge protector through the filter circuit; the second input end of the differential amplifier is electrically connected to the second voltage dividing node through the filter circuit, or the second input end of the differential amplifier is electrically connected to the input end of the high-voltage sampling module through the filter circuit; The output end of the differential amplifier is electrically connected to the main control module through the follower circuit.

9. A high-voltage sampling method, characterized in that: A high-voltage sampling system according to any one of claims 1 to 8; The high-voltage sampling method comprises: Obtaining a first feedback signal output by the first monitoring module; determining, according to the first feedback signal, whether the voltage of the first voltage-dividing node is abnormal; When the voltage of the first voltage dividing node is abnormal, controlling the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage dividing unit; When the voltage of the first voltage-dividing node is normal, the high-voltage sampling signal output by the high-voltage sampling module is obtained to complete the high-voltage sampling task of the high-voltage bus.

10. The high-voltage sampling method according to claim 9, characterized in that: The high-voltage sampling system further includes a first current-limiting resistor, a series-blocking surge protector, and a second monitoring module; the high-voltage sampling module is electrically connected to the second voltage-dividing node through the first current-limiting resistor and the series-blocking surge protector; the second monitoring module is electrically connected to the second voltage-dividing node through the first current-limiting resistor and / or the series-blocking surge protector; the second monitoring module is configured to monitor the voltage of the second voltage-dividing node and provide a second feedback signal to the main control module when the voltage of the second voltage-dividing node is abnormal; Obtaining the high-voltage sampling signal output by the high-voltage sampling module to complete the high-voltage sampling task of the high-voltage bus includes: Obtaining a second feedback signal output by the second monitoring module; determining, according to the second feedback signal, whether the voltage of the second voltage-dividing node is abnormal; When the voltage of the second voltage dividing node is abnormal, controlling the switch control module to disconnect the connection path between the high-voltage bus and the primary voltage dividing unit; When the voltage of the second voltage-dividing node is normal, the high-voltage sampling signal output by the high-voltage sampling module is obtained to complete the high-voltage sampling task of the high-voltage bus.

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