A power protection device and battery management system

Abstract

The application discloses a power protection device and a battery management system. The power protection device comprises a first switch module, a power supply supplies power to a rear-stage load through the first switch module; a voltage difference exists between the control end and the first end of a second switch module and a voltage difference exists between the control end and the first end of a third switch module; the second switch module is used for charging the control end of the first switch module in a conduction state to control the first switch module to be turned on; the third switch module is used for controlling the first switch module to be turned off when the device exceeds a set voltage and limiting the current increase of the first switch module when the current of the rear-stage load exceeds a set current; and a comparison module is used for controlling the on-off of the first switch module by controlling the second switch module in a set time interval. The application improves the power consumption reliability of the rear-end load.

Description

Technical Field

[0001] This invention relates to the field of power protection technology, and more particularly to a power protection device and a battery management system. Background Technology

[0002] During the operation or debugging of battery management systems, issues such as hot-plugging, incorrect connection, short circuits, and reverse power connection of downstream loads frequently occur. Because downstream loads lack protection devices, hot-plugging can easily cause arcing and flashover, while incorrect wiring can lead to short circuits, burnout, or even complete failure of the downstream load, severely impacting debugging and development progress. Therefore, the power supply provided by existing technologies has poor reliability when supplying power to downstream loads. Summary of the Invention

[0003] This invention provides a power protection device and a battery management system to solve the problem of poor power reliability for downstream loads.

[0004] According to one aspect of the present invention, a power protection device is provided, comprising:

[0005] A first switching module, wherein a first terminal and a second terminal of the first switching module are connected in series between the power supply terminal and the downstream load, and a voltage difference exists between the control terminal and the first terminal of the first switching module; the power supply provides power to the downstream load through the first switching module.

[0006] A voltage divider module and a second switch module are included. The control terminal of the second switch module is electrically connected to the power supply terminal through the voltage divider module. The first terminal of the second switch module is electrically connected to the reference voltage terminal. The second terminal of the second switch module is electrically connected to the control terminal of the first switch module. There is a voltage difference upper limit clamp between the control terminal and the first terminal of the second switch module. The second switch module is used to charge the control terminal of the first switch module in the on state to control the first switch module to be on.

[0007] A third switch module has a first terminal electrically connected to the power supply terminal, a second terminal electrically connected to the control terminal of the first switch module, and a control terminal electrically connected to the first terminal of the first switch module. A voltage difference exists between the control terminal and the first terminal of the third switch module. The third switch module is used to control the first switch module to disconnect when the device exceeds a set voltage, and to limit the current increase of the first switch module when the current of the downstream load exceeds a set current.

[0008] The comparison module has a first terminal electrically connected to the power supply terminal, a second terminal electrically connected to the second terminal of the third switch module, and a third terminal electrically connected to the control terminal of the second switch module. The comparison module is used to control the on / off state of the first switch module by controlling the second switch module at a set time interval.

[0009] Optionally, the first switching module includes a first switching transistor, a first resistor, and a first Zener diode;

[0010] The control terminal of the first switching transistor serves as the control terminal of the first switching module, the first terminal of the first switching transistor serves as the first terminal of the first switching module, and the second terminal of the first switching transistor serves as the second terminal of the first switching module.

[0011] The first resistor is connected between the control electrode and the first electrode of the first switching transistor;

[0012] The positive terminal of the first Zener diode is electrically connected to the control terminal of the first switching transistor, and the negative terminal of the first Zener diode is electrically connected to the first terminal of the first switching transistor.

[0013] Optionally, the voltage divider module includes a second resistor, with a first end of the second resistor serving as a first end of the voltage divider module and a second end of the second resistor serving as a second end of the voltage divider module;

[0014] And / or, the second switching module includes: a second switching transistor, a third resistor, a fourth resistor, a fifth resistor, and a second Zener diode;

[0015] Wherein, the first end of the third resistor serves as the control end of the second switching module, the second end of the third resistor is electrically connected to the control electrode of the second switching transistor, the first end of the fourth resistor is electrically connected to the second end of the third resistor, the second end of the fourth resistor is electrically connected to the second electrode of the second switching transistor, the first electrode of the second switching transistor is connected to the second end of the second switching module through the fifth resistor, the second electrode of the second switching transistor is electrically connected to the reference voltage end, and the second electrode of the second switching transistor serves as the first end of the second switching module;

[0016] The positive terminal of the second Zener diode is electrically connected to the second terminal of the second switching transistor, and the negative terminal of the second Zener diode is electrically connected to the control terminal of the second switching transistor.

[0017] Optionally, the third switch module includes:

[0018] The third switch transistor has its first terminal serving as the first terminal of the third switch module, and its second terminal serving as the second terminal of the third switch module.

[0019] A first control branch, the first end of which is electrically connected to the control electrode of the third switch, is used to control the third switch to conduct when the device exceeds the set voltage.

[0020] The second control branch has a first end electrically connected to the control electrode of the third switch transistor, a second end electrically connected to the first electrode of the third switch transistor, and a third end serving as the control terminal of the third switch module. The second control branch is used to limit the current increase of the first switch module when the current of the downstream load exceeds a set current.

[0021] Optionally, the first control branch includes a sixth resistor and a third Zener diode connected in series between the control electrode of the third switch and the reference voltage terminal; wherein the positive terminal of the third Zener diode is electrically connected to the reference voltage terminal, and the negative terminal of the third Zener diode is connected to the control electrode of the third switch through the sixth resistor;

[0022] And / or, the second control branch includes a seventh resistor, an eighth resistor, and a first diode; the first end of the seventh resistor serves as the second end of the second control branch; the second end of the seventh resistor is electrically connected to the cathode of the first diode and serves as the third end of the second control branch; the anode of the first diode is electrically connected to the first end of the eighth resistor, and the second end of the eighth resistor serves as the first end of the second control branch.

[0023] Optionally, the comparison module includes:

[0024] The first input unit has a first terminal serving as the first terminal of the comparison module, and a second terminal of the first input unit being electrically connected to the reference voltage terminal. The first input unit is used to divide the voltage between its first and second terminals and output it through its third terminal.

[0025] The second input unit has a first terminal serving as the second terminal of the comparison module, and the second terminal of the second input unit is electrically connected to the reference voltage terminal. The second input unit is used to be charged by the third switch module to control the voltage of its third terminal to change intermittently at a set interval.

[0026] The comparator unit has a first input terminal electrically connected to the third terminal of the first input unit, a second input terminal electrically connected to the third terminal of the second input unit, and an output terminal serving as the third terminal of the comparison module.

[0027] Optionally, the first input unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a fourth Zener diode, and a first capacitor; the first end of the ninth resistor serves as the first end of the first input unit, and the second end of the ninth resistor is electrically connected to the first end of the tenth resistor; the second end of the tenth resistor is electrically connected to the first end of the eleventh resistor and serves as the third end of the first input unit; the second end of the eleventh resistor serves as the second end of the first input unit; the fourth Zener diode is connected between the second end of the ninth resistor and the reference voltage terminal; and the first capacitor is connected between the second end of the tenth resistor and the reference voltage terminal.

[0028] And / or, the second input unit includes a twelfth resistor, a thirteenth resistor, a fifth Zener diode, and a second capacitor; the twelfth resistor serves as the first terminal of the second input unit, the second terminal of the twelfth resistor serves as the third terminal of the second input unit, the first terminal of the thirteenth resistor is electrically connected to the second terminal of the twelfth resistor, and the second terminal of the thirteenth resistor serves as the second terminal of the second input unit; the fifth Zener diode is connected in parallel across the thirteenth resistor; the second capacitor is connected in parallel across the thirteenth resistor;

[0029] And / or, the comparator unit includes a comparator and a second diode, the first input terminal of the comparator serves as the first input terminal of the comparator unit, the second input terminal of the comparator serves as the second input terminal of the comparator unit, and the output terminal of the comparator serves as the output terminal of the comparator unit; the second diode is connected between the first input terminal and the output terminal of the comparator.

[0030] Optionally, the power protection device further includes:

[0031] A protection module is connected to the front end of the power protection device to provide overvoltage protection and / or reverse connection protection for the power supply.

[0032] According to another aspect of the present invention, a battery management system is provided, comprising: a power supply, a downstream load, and a power protection device as described in any embodiment of the present invention; wherein the power protection device is connected in series between the power supply and the downstream load.

[0033] Optionally, the downstream load includes at least one of a power device, a drive device, and a control device; the power supply branch of the power device is a power branch, the power supply branch of the drive device is a drive branch, and the power supply branch of the control device is a control branch.

[0034] The power protection device is connected in series in the power branch, in series in the drive branch, and / or in series in the control branch.

[0035] The technical solution provided in this invention addresses the issue that, when the power supply supplies power to a downstream load, the first switching module is defaulted to an off state. By setting a second switching module to charge the first switching module, the first switching module is gradually turned on, causing the current flowing into the capacitor of the downstream load to gradually increase. This avoids the problem of excessive current surges and arcing caused by sudden changes in capacitor voltage in the downstream load at the moment of power supply. Furthermore, by setting a third switching module, when the current flowing from the first switching module to the downstream load exceeds a set current, the conduction level of the first switching module is limited, maintaining the current in a stable state, suppressing arcing current, and limiting arcing energy. Moreover, when the power protection device experiences overvoltage, the third switching module can disconnect the first switching module, protecting the downstream load from excessive voltage and improving the reliability of the power protection device. Finally, by setting a comparison module, overheat protection for the first switching module is achieved. In summary, the embodiments of the present invention provide power supply protection for downstream loads, avoid overcurrent and overvoltage in downstream loads, prevent arcing and flashover caused by sudden changes in voltage or current in capacitors in downstream loads, and improve the reliability of power supply.

[0036] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of a power protection device according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of another power protection device provided according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of another power protection device provided according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of another power protection device provided according to an embodiment of the present invention;

[0042] Figure 5 This is a voltage simulation diagram of a power protection device according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of a battery management system according to an embodiment of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] This invention provides a power protection device. Figure 1 This is a schematic diagram of a power protection device provided in an embodiment of the present invention. (Reference) Figure 1The power protection device includes: a first switch module 1, a voltage divider module 4, a second switch module 2, a third switch module 3, and a comparator module 5. The first and second terminals of the first switch module 1 are connected in series between the power supply terminal and the downstream load 6. A voltage difference exists between the control terminal and the first terminal of the first switch module 1. The power supply provides power to the downstream load 6 through the first switch module 1. The control terminal of the second switch module 2 is electrically connected to the power supply terminal through the voltage divider module 4. The first terminal of the second switch module 2 is electrically connected to a reference voltage terminal; exemplarily, the reference voltage terminal can be a ground terminal. The second terminal of the second switch module 2 is electrically connected to the control terminal of the first switch module 1. A voltage difference upper limit clamp exists between the control terminal and the first terminal of the second switch module 2. The second switch module 2 is used to charge the control terminal of the first switch module 1 in the on state to control the first switch module 1 to conduct. The first terminal of the third switch module 3 is electrically connected to the power supply terminal, and the second terminal of the third switch module 3 is electrically connected to the control terminal of the first switch module 1. The control terminal of the third switch module 3 is also electrically connected to the first terminal of the first switch module 1. There is a voltage difference between the control terminal and the first terminal of the third switch module 3. The third switch module 3 is used to control the first switch module 1 to disconnect when the device exceeds a set voltage, and to limit the current increase of the first switch module 1 when the current of the downstream load 6 exceeds a set current. The first terminal of the comparison module 5 is electrically connected to the power supply terminal, and the second terminal of the comparison module 5 is electrically connected to the second terminal of the third switch module 3. The third terminal of the comparison module 5 is electrically connected to the control terminal of the second switch module 2. The comparison module 5 is used to control the on / off state of the first switch module 1 by controlling the second switch module 2 at set time intervals.

[0047] When the power supply supplies power to the power protection device, the third switch module 3 and the first switch module 1 are in the off state. At this time, there is no conduction between the first and second terminals of the third switch module 3 and the first switch module 1, and the downstream load 6 is not energized. This prevents the capacitor in the downstream load 6 from generating a current surge due to the instantaneous connection of the power supply. This avoids the problem of arcing and flashover of the capacitor at the moment of power supply.

[0048] Simultaneously, the power supply supplies power to the second switch module 2 through the voltage divider module 4, causing the control terminal and the first terminal of the second switch module 2 to conduct due to the voltage difference. An upper limit clamp for the voltage difference between the control terminal and the first terminal of the second switch module 2 is used to limit the voltage difference between them, preventing damage to the second switch module 2 due to excessive voltage. After the second switch module 2 is turned on, the power supply charges the control terminal of the first switch module 1 through the second switch module 2. When the voltage difference between the control terminal and the first terminal of the first switch module 1 reaches the conduction voltage of the first switch module 1, the first switch module 1 gradually turns on. As the voltage difference between the control terminal and the first terminal continuously increases, the conduction degree of the first switch module 1 also continuously increases, causing the current flowing into the first switch module 1 to gradually increase.

[0049] When the current flowing into the downstream load 6 through the first switching module 1 continuously increases and exceeds the set current value, the current flowing through the third switching module 3 also gradually increases, causing the voltage difference between the control terminal and the first terminal of the third switching module 3 to gradually increase, and the conduction degree of the third switching module 3 to continuously increase. At this time, the second terminal of the third switching module 3 outputs a larger current, thereby increasing the potential at the connection point between the second switching module 2 and the first switching module 1. Therefore, the voltage difference between the control terminal and the first terminal of the first switching module 1 decreases, the conduction degree of the first switching module 1 decreases, limiting the increase of the current in the first switching module 1, thereby limiting the arcing energy of the capacitor in the downstream load 6. When a short-circuit fault occurs in the downstream load 6, the short-circuit current will also be limited because the current in the first switching module 1 exceeds the set current value.

[0050] The third switch module 3 can also be used for overvoltage protection. When the voltage of the power protection device exceeds the set voltage, the voltage can be directly grounded through the third switch module 3 and the first switch module 1 can be disconnected, so that the downstream load 6 is protected from excessive voltage.

[0051] Because the first switch module 1 is in a semi-conducting state, it will experience thermal stress due to heat generation during operation. The comparator module 5 can intermittently control the on / off state of the first switch module 1, thereby reducing the heat generation of the first switch module 1.

[0052] The technical solution provided in this embodiment of the invention, when the power supply supplies power to the downstream load 6, the first switch module 1 is in a default off state. By setting the second switch module 2 to charge the first switch module 1, the first switch module 1 is gradually turned on, causing the current flowing into the capacitor in the downstream load 6 to gradually increase. This avoids the problem of excessive current surges and arcing caused by sudden changes in the capacitor voltage in the downstream load 6 at the moment of power supply. Furthermore, by setting the third switch module 3, when the current flowing into the downstream load 6 from the first switch module 1 exceeds a set current, the conduction degree of the first switch module 1 is limited, so that the current can be maintained in a stable state, suppressing arcing current and limiting arcing energy. Moreover, when the power protection device is overvoltageed, the third switch module 3 can disconnect the first switch module 1, protecting the downstream load 6 from excessive voltage and improving the reliability of the power protection device. Finally, by setting the comparison module 5, heat protection for the first switch module 1 is achieved. In summary, the embodiments of the present invention provide power protection for the downstream load 6, avoid overcurrent and overvoltage of the downstream load 6, prevent arcing and flashover caused by sudden changes in voltage or current in the capacitors of the downstream load 6, and improve the reliability of power supply.

[0053] Figure 2 This is a schematic diagram of another power protection device provided in an embodiment of the present invention. (Refer to...) Figure 2 Based on the above embodiments, optionally, the first switching module includes a first switching transistor Q1, a first resistor R1, and a first Zener diode VD1. The control electrode of the first switching transistor Q1 serves as the control terminal of the first switching module 1, the first electrode of the first switching transistor Q1 serves as the first terminal of the first switching module 1, and the second electrode of the first switching transistor Q1 serves as the second terminal of the first switching module 1; the first resistor R1 is connected between the control electrode and the first electrode of the first switching transistor Q1; the positive electrode of the first Zener diode VD1 is electrically connected to the control electrode of the first switching transistor Q1, and the negative electrode of the first Zener diode VD1 is electrically connected to the first electrode of the first switching transistor Q1.

[0054] In this circuit, the first resistor R1 is connected between the control electrode and the first electrode of the first switching transistor Q1. When current flows through the first resistor R1, a voltage is generated across it. By connecting the first Zener diode VD1 in parallel across the first resistor R1, the voltage across it can be limited. This effectively limits the maximum voltage between the control electrode and the first electrode of the first switching transistor Q1, protecting it from damage due to excessive voltage.

[0055] Continue to refer to Figure 2Based on the above embodiments, optionally, the voltage divider module 4 includes a second resistor R2, the first end of the second resistor R2 serves as the first end of the voltage divider module 4, and the second end of the second resistor R2 serves as the second end of the voltage divider module 4; and / or, the second switch module 2 includes: a second switch transistor Q2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a second Zener diode VD2; wherein, the first end of the third resistor R3 serves as the control terminal of the second switch module 2, the second end of the third resistor R3 is electrically connected to the control electrode of the second switch transistor Q2, the first end of the fourth resistor R4 is electrically connected to the second end of the third resistor R3, the second end of the fourth resistor R4 is electrically connected to the second electrode of the second switch transistor Q2, the first electrode of the second switch transistor Q2 is connected to the second end of the second switch module 2 through the fifth resistor R5, the second electrode of the second switch transistor Q2 is electrically connected to the reference voltage terminal, and the second electrode of the second switch transistor Q2 serves as the first end of the second switch module 2; the positive electrode of the second Zener diode VD2 is electrically connected to the second electrode of the second switch transistor Q2, and the negative electrode of the second Zener diode VD2 is electrically connected to the control electrode of the second switch transistor.

[0056] The power supply supplies power to the second switching module 2 through the second resistor R2. A circuit is formed between the second resistor R2, the third resistor R3, and the fourth resistor R4, generating a voltage across the fourth resistor R4. The fourth resistor R4 is connected in parallel between the control electrode and the second electrode of the second switching transistor Q2, creating a voltage difference that turns on Q2. The second Zener diode VD2 limits the voltage between the control electrode and the second electrode of Q2, preventing damage to Q2 due to overvoltage.

[0057] After the second switch Q2 is turned on, it can charge the first switch Q1 through its first terminal. When the voltage between the control terminal and the first terminal of the first switch Q1 reaches the turn-on voltage, the first switch Q1 gradually turns on, and the power supply supplies power to the subsequent load 6 through the first switch Q1. By setting the third diode D3, the reverse flow of current from the second switch Q2 into the third switch module 3 can be prevented.

[0058] Continue to refer to Figure 2Based on the above embodiments, optionally, the third switch module 3 includes: a third switch transistor Q3, a first control branch 31, and a second control branch 32. The first terminal of the third switch transistor Q3 serves as the first terminal of the third switch module 3, and the second terminal of the third switch transistor Q3 serves as the second terminal of the third switch module 3. The first terminal of the first control branch 31 is electrically connected to the control terminal of the third switch transistor Q3, and the first control branch 31 is used to control the third switch transistor Q3 to conduct when the device exceeds a set voltage. The first terminal of the second control branch 32 is electrically connected to the control terminal of the third switch transistor Q3, and the second terminal of the second control branch 32 is electrically connected to the first terminal of the third switch transistor Q3. The third terminal of the second control branch 32 serves as the control terminal of the third switch module 3. The second control branch 32 is used to limit the increase of the current of the first switch module 1 when the current of the downstream load 6 exceeds a set current.

[0059] The first control branch 31 is an overvoltage protection branch. When the voltage input to the first control branch 31 exceeds a set voltage, the third switch Q3 is turned on. The third switch Q3 has a low turn-on voltage, exemplarily 0.7V. Therefore, when the third switch Q3 is turned on, the voltage between the control electrode and the first electrode of the first switch Q1 can be limited to 0.7V, which is below the turn-on voltage of the first switch Q1, causing the first switch Q1 to turn off. Simultaneously, the first control branch 31 can ground excessively high voltages, thereby preventing damage to the power supply protection device due to excessively high voltages.

[0060] The second control branch 32 is an overcurrent protection branch. When the current of the downstream load 6 continues to increase, the voltage of the second control branch 32 will also increase, causing the conduction degree of the third switch Q3 to increase continuously. The second terminal of the third switch Q3 outputs a larger current, which raises the potential of the fifth resistor R5. This is equivalent to reducing the voltage difference between the control terminal and the first terminal of the first switch Q1, thus reducing the conduction degree of the first switch Q1 and limiting the current input to the downstream load 6 by the first switch Q1, allowing the first switch Q1 to be maintained in the constant current region.

[0061] Continue to refer to Figure 2Based on the above embodiments, optionally, the first control branch 31 includes a sixth resistor R6 and a third Zener diode VD3 connected in series between the control electrode and the reference voltage terminal of the third switch Q3; wherein the positive terminal of the third Zener diode VD3 is electrically connected to the reference voltage terminal, and the negative terminal of the third Zener diode VD3 is connected to the control electrode of the third switch Q3 through the sixth resistor R6; and / or, the second control branch 32 includes a seventh resistor R7, an eighth resistor R8, and a first diode D1; the first end of the seventh resistor R7 serves as the second end of the second control branch 32; the second end of the seventh resistor R7 is electrically connected to the cathode of the first diode D1 and serves as the third end of the second control branch 32; the anode of the first diode D1 is electrically connected to the first end of the eighth resistor R8, and the second end of the eighth resistor R8 serves as the first end of the second control branch 32.

[0062] For example, when the power supply voltage is 24V and a 20% allowable overvoltage value is set, the third Zener diode VD3 can be selected as a 28V Zener diode. When the turn-on voltage of the third switch Q3 is 0.7V, if the voltage input to the power supply terminal is greater than 28.7V, the third Zener diode VD3 will break down. The power supply is grounded through the sixth resistor R6 and the third Zener diode VD3, avoiding the impact of excessive voltage on the power protection device. Furthermore, because the turn-on voltage of the third switch Q3 is 0.7V, the voltage difference between the control electrode and the first electrode of the first switch Q1 is also 0.7V. This small voltage value will not cause the first switch Q1 to conduct.

[0063] The first switching transistor Q1 can be a bipolar transistor. As Q1 gradually turns on, the current flowing through the seventh resistor R7 gradually increases. When the voltage drop across R7 reaches a certain value, the collector junction of the third switching transistor Q3 becomes forward biased, and current flows through its base. This completes the circuit connecting the eighth resistor R8, the first diode D1, and the subsequent load 6, thus turning on Q3. After Q3 turns on, as the current flowing through R7 gradually increases, the conduction level of Q3 also gradually increases, resulting in a larger current output from its collector. This, in turn, raises the potential of the fifth resistor R5. The higher potential of R5 effectively reduces the voltage difference between the control and first terminals of Q1, decreasing its conduction level and limiting the current input to the subsequent load 6. At this point, negative feedback is formed, and Q1 remains in the constant current region.

[0064] Figure 3 This is a schematic diagram of another power protection device provided in an embodiment of the present invention. (See reference) Figure 3Based on the above embodiments, optionally, the comparison module 5 includes: a first input unit 51, the first end of which serves as the first end of the comparison module 5, and the second end of which is electrically connected to a reference voltage terminal. The first input unit 51 is used to divide the voltage between its first and second ends and output it through its third end. A second input unit 52, the first end of which serves as the second end of the comparison module 5, and the second end of which is electrically connected to the reference voltage terminal. The second input unit 52 is used to be charged by the third switch module 3 to control the voltage of its third end to change intermittently at a set interval. A comparator unit 53, the first input end of which is electrically connected to the third end of the first input unit 51, the second input end of which is electrically connected to the third end of the first input unit 51, and the output end of the comparator unit 53 serving as the third end of the comparison module 5.

[0065] The first input unit 51 divides the voltage between its first and second terminals and inputs this voltage to the first input terminal of the comparator unit 53. This first input terminal can be a non-inverting input. When the third switch Q3 is turned on, the second input unit 52 begins charging and inputs this charging voltage to the second input terminal of the comparator unit 53. When the charging voltage does not reach the voltage at the first input terminal of the comparator unit 53, the comparator unit 53 outputs a high level, and the second switch Q2 remains on. When the charging voltage reaches the voltage at the first input terminal of the comparator unit 53, the comparator unit 53 reverses to a low level, turning off the second switch Q2, which in turn turns off the first switch Q1 and the third switch Q3. At this time, the first input terminal of the comparator unit 53 has a small input voltage, and simultaneously, the second input unit 52 begins discharging to the second input terminal of the comparator unit 53. This second input terminal can be an inverting input. When the discharge voltage reaches the voltage at the first input terminal of comparator unit 53, comparator unit 53 outputs a high level, causing the second switch Q2 to conduct, which in turn turns on the first switch Q1, allowing the first switch Q1 to continue operating. This embodiment of the invention achieves intermittent switching on and off of the first switch Q1, the second switch Q2, and the third switch Q3, reducing the thermal stress on these switches and lowering the selection requirements for them, thus reducing the cost of the power protection device.

[0066] Continue to refer to Figure 3Based on the above embodiments, optionally, the first input unit 51 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a fourth Zener diode VD4, and a first capacitor C1; the first end of the ninth resistor R9 serves as the first end of the first input unit 51, and the second end of the ninth resistor R9 is electrically connected to the first end of the tenth resistor R10; the second end of the tenth resistor R10 is electrically connected to the first end of the eleventh resistor R11 and serves as the third end of the first input unit 51; the second end of the eleventh resistor R11 serves as the second end of the first input unit 51, the fourth Zener diode VD4 is connected between the second end of the ninth resistor R9 and the reference voltage end, and the first capacitor C1 is connected between the second end of the tenth resistor R10 and the reference voltage end.

[0067] For example, when the power supply is 24V, the fourth Zener diode VD4 can be a 5V Zener diode, and the tenth resistor R10 and the eleventh resistor R11 are set to the same resistance value. The tenth resistor R10 and the eleventh resistor R11 each receive a voltage of 2.5V and are input to the first input terminal of the comparator unit 53.

[0068] Optionally, the second input unit 52 includes a twelfth resistor R12, a thirteenth resistor R13, a fifth Zener diode VD5, and a second capacitor C2; the twelfth resistor R12 serves as the first terminal of the second input unit, the second terminal of the twelfth resistor R12 serves as the third terminal of the second input unit, the first terminal of the thirteenth resistor R13 is electrically connected to the second terminal of the twelfth resistor R12, and the second terminal of the thirteenth resistor R13 serves as the second terminal of the second input unit 52; the fifth Zener diode VD5 is connected in parallel across the thirteenth resistor R13; and the second capacitor C2 is connected in parallel across the thirteenth resistor R13. The comparator unit 53 includes a comparator U1 and a second diode D2; the first input terminal of the comparator U1 serves as the first input terminal of the comparator unit 53, the second input terminal of the comparator U1 serves as the second input terminal of the comparator unit 53, and the output terminal of the comparator U1 serves as the output terminal of the comparator unit 53; the second diode D2 is connected between the first input terminal and the output terminal of the comparator U1.

[0069] The fifth Zener diode, VD5, acts as a clamp to prevent excessive voltage from being applied to the second input terminal of comparator U1, which could damage U1. When the third switch, Q3, is turned on, the second capacitor, C2, begins to charge. Before the charging voltage of C2 reaches 2.5V, comparator U1 outputs a high level, and the second switch, Q2, remains on. When the charging voltage of C2 reaches 2.5V, comparator U1 reverses to a low level, and the second switch, Q2, turns off.

[0070] After the second switch Q2 is turned off, for example, when the forward voltage of the second diode D2 is 0.7V, the voltage at the first input terminal of comparator U1 becomes 0.7V. The second capacitor C2 begins to discharge. Since the fourth diode D4 is provided, the discharge circuit of the second capacitor C2 consists only of the thirteenth resistor R13. When the voltage of the thirteenth resistor R13 reaches 0.7V, comparator U1 reverses to a high level, and the first switch Q1, the second switch Q2, and the third switch Q3 gradually turn on again.

[0071] Figure 4 This is a schematic diagram of another power protection device provided in an embodiment of the present invention. (See reference) Figure 4 Based on the above embodiments, optionally, the power protection device further includes: a protection module 7, which is connected to the front end of the power protection device to provide overvoltage protection and / or reverse connection protection for the power supply.

[0072] The protection module 7 includes a fuse F1, a sixth Zener diode VD6, and a seventh Zener diode VD7. In other embodiments, the fuse F1 can also be a fusible linker, and the sixth Zener diode VD6 and the seventh Zener diode VD7 can also be TVS diodes (transient voltage suppressor diodes).

[0073] For example, if all components of the power protection device can withstand a maximum voltage of 100V, then the breakdown voltage of the sixth Zener diode VD6 and the seventh Zener diode VD7 can be selected as approximately 80V. If the maximum withstand voltage is 50V, then the breakdown voltage of the sixth Zener diode VD6 and the seventh Zener diode VD7 can be selected as approximately 40V, which can be set according to design requirements. Using the sixth Zener diode VD6 and the seventh Zener diode VD7 in parallel increases the overcurrent capacity compared to using a single Zener diode. The fuse F1 can be selected based on the highest voltage of the power protection device to ensure that any power supply voltage connected to the power protection device can protect the downstream load 6, effectively preventing damage to the downstream load 6.

[0074] The sixth Zener diode VD6 and the seventh Zener diode VD7 are both unidirectional Zener diodes. When the power supply is reversed, the sixth Zener diode VD6 and the seventh Zener diode VD7 have a low forward voltage, thus protecting the power supply protection device. Even if the reversed input voltage is too large, the fuse F1 will blow, thereby cutting off the power supply.

[0075] Figure 5 A voltage simulation diagram of a power protection device provided in an embodiment of the present invention. (Reference) Figure 5 Optionally, the red line represents the input voltage Vin of the power protection device, and the green line represents the output voltage Vout of the power protection device. For example... Figure 5 As shown, when the power protection device is connected to voltage, the first switch is not turned on, and the output voltage Vout of the power protection device is 0. When the input voltage Vin reaches 8V, the first switch gradually turns on, and the output voltage Vout of the power protection device gradually rises and reaches the voltage value of the input voltage Vin. When the input voltage Vin continues to rise and reaches the set maximum voltage value, the first switch turns off, and the output voltage Vout of the power protection device is 0.

[0076] This invention also provides a battery management system. Figure 6 This is a schematic diagram of a battery management system provided in an embodiment of the present invention. (Reference) Figure 6 The battery management system includes a power supply, a downstream load 6, and a power protection device 10 provided in any embodiment of the present invention; wherein the power protection device 10 is connected in series between the power supply and the downstream load 6. This battery management system has similar beneficial effects to the power protection device provided in any of the above embodiments, and will not be described in detail here.

[0077] Continue to refer to Figure 6 Based on the above embodiments, optionally, the downstream load 6 includes at least one of a power device 61, a drive device 62, and a control device 63; the power supply branch of the power device 61 is a power branch, the power supply branch of the drive device 62 is a drive branch, and the power supply branch of the control device 63 is a control branch. The power protection device 10 is connected in series in the power branch, in series in the drive branch, and / or in series in the control branch.

[0078] The battery management system has multiple power supply branches. Without a power protection device 10, a short circuit or other fault in one of the power supply branches will cause the voltage of all power supply branches to drop, thus affecting the normal operation of the entire battery management system. This embodiment of the invention connects a power protection device 10 in series with each power supply branch. When a fault occurs in one power supply branch, the power protection device 10 limits the current and voltage in that branch, preventing it from affecting other power supply branches and improving the reliability of the battery management system.

[0079] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0080] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A power supply protection device, characterized in that, include: A first switching module, wherein a first terminal and a second terminal of the first switching module are connected in series between the power supply terminal and the downstream load, and a voltage difference exists between the control terminal and the first terminal of the first switching module; the power supply provides power to the downstream load through the first switching module. A voltage divider module and a second switch module are included. The control terminal of the second switch module is electrically connected to the power supply terminal through the voltage divider module. The first terminal of the second switch module is electrically connected to the reference voltage terminal. The second terminal of the second switch module is electrically connected to the control terminal of the first switch module. There is a voltage difference upper limit clamp between the control terminal and the first terminal of the second switch module. The second switch module is used to charge the control terminal of the first switch module in the on state to control the first switch module to be on. A third switch module has a first terminal electrically connected to the power supply terminal, a second terminal electrically connected to the control terminal of the first switch module, and a control terminal electrically connected to the first terminal of the first switch module. A voltage difference exists between the control terminal and the first terminal of the third switch module. The third switch module is used to control the first switch module to disconnect when the device exceeds a set voltage, and to limit the current increase of the first switch module when the current of the downstream load exceeds a set current. The comparison module has a first terminal electrically connected to the power supply terminal, a second terminal electrically connected to the second terminal of the third switch module, and a third terminal electrically connected to the control terminal of the second switch module. The comparison module is used to control the on / off state of the first switch module by controlling the second switch module at a set time interval.

2. The power protection device according to claim 1, characterized in that, The first switching module includes a first switching transistor, a first resistor, and a first Zener diode; The control terminal of the first switching transistor serves as the control terminal of the first switching module, the first terminal of the first switching transistor serves as the first terminal of the first switching module, and the second terminal of the first switching transistor serves as the second terminal of the first switching module. The first resistor is connected between the control electrode and the first electrode of the first switching transistor; The positive terminal of the first Zener diode is electrically connected to the control terminal of the first switching transistor, and the negative terminal of the first Zener diode is electrically connected to the first terminal of the first switching transistor.

3. The power protection device according to claim 1, characterized in that, The voltage divider module includes a second resistor, with the first end of the second resistor serving as the first end of the voltage divider module and the second end of the second resistor serving as the second end of the voltage divider module. And / or, the second switching module includes: a second switching transistor, a third resistor, a fourth resistor, a fifth resistor, and a second Zener diode; Wherein, the first end of the third resistor serves as the control end of the second switching module, the second end of the third resistor is electrically connected to the control electrode of the second switching transistor, the first end of the fourth resistor is electrically connected to the second end of the third resistor, the second end of the fourth resistor is electrically connected to the second electrode of the second switching transistor, the first electrode of the second switching transistor is connected to the second end of the second switching module through the fifth resistor, the second electrode of the second switching transistor is electrically connected to the reference voltage end, and the second electrode of the second switching transistor serves as the first end of the second switching module; The positive terminal of the second Zener diode is electrically connected to the second terminal of the second switching transistor, and the negative terminal of the second Zener diode is electrically connected to the control terminal of the second switching transistor.

4. The power protection device according to claim 1, characterized in that, The third switch module includes: The third switch transistor, wherein the first terminal of the third switch transistor serves as the first terminal of the third switch module, and the second terminal of the third switch transistor serves as the second terminal of the third switch module; A first control branch, the first end of which is electrically connected to the control electrode of the third switch, is used to control the third switch to conduct when the device exceeds the set voltage. The second control branch has a first end electrically connected to the control electrode of the third switch transistor, a second end electrically connected to the first electrode of the third switch transistor, and a third end serving as the control terminal of the third switch module. The second control branch is used to limit the current increase of the first switch module when the current of the downstream load exceeds a set current.

5. The power protection device according to claim 4, characterized in that, The first control branch includes a sixth resistor and a third Zener diode connected in series between the control electrode of the third switch and the reference voltage terminal; wherein the positive terminal of the third Zener diode is electrically connected to the reference voltage terminal, and the negative terminal of the third Zener diode is connected to the control electrode of the third switch through the sixth resistor; And / or, the second control branch includes a seventh resistor, an eighth resistor, and a first diode; the first end of the seventh resistor serves as the second end of the second control branch; the second end of the seventh resistor is electrically connected to the cathode of the first diode and serves as the third end of the second control branch; the anode of the first diode is electrically connected to the first end of the eighth resistor, and the second end of the eighth resistor serves as the first end of the second control branch.

6. The power protection device according to claim 1, characterized in that, The comparison module includes: The first input unit has a first terminal serving as the first terminal of the comparison module, and a second terminal of the first input unit being electrically connected to the reference voltage terminal. The first input unit is used to divide the voltage between its first and second terminals and output it through its third terminal. The second input unit has a first terminal serving as the second terminal of the comparison module, and the second terminal of the second input unit is electrically connected to the reference voltage terminal. The second input unit is used to be charged by the third switch module to control the voltage of its third terminal to change intermittently at a set interval. The comparator unit has a first input terminal electrically connected to the third terminal of the first input unit, a second input terminal electrically connected to the third terminal of the second input unit, and an output terminal serving as the third terminal of the comparison module.

7. The power protection device according to claim 6, characterized in that, The first input unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a fourth Zener diode, and a first capacitor; the first terminal of the ninth resistor serves as the first terminal of the first input unit, and the second terminal of the ninth resistor is electrically connected to the first terminal of the tenth resistor; the second terminal of the tenth resistor is electrically connected to the first terminal of the eleventh resistor and serves as the third terminal of the first input unit; the second terminal of the eleventh resistor serves as the second terminal of the first input unit; the fourth Zener diode is connected between the second terminal of the ninth resistor and the reference voltage terminal; and the first capacitor is connected between the second terminal of the tenth resistor and the reference voltage terminal. And / or, the second input unit includes a twelfth resistor, a thirteenth resistor, a fifth Zener diode, and a second capacitor; the twelfth resistor serves as the first terminal of the second input unit, the second terminal of the twelfth resistor serves as the third terminal of the second input unit, the first terminal of the thirteenth resistor is electrically connected to the second terminal of the twelfth resistor, and the second terminal of the thirteenth resistor serves as the second terminal of the second input unit; the fifth Zener diode is connected in parallel across the thirteenth resistor; the second capacitor is connected in parallel across the thirteenth resistor; And / or, the comparator unit includes a comparator and a second diode, the first input terminal of the comparator serves as the first input terminal of the comparator unit, the second input terminal of the comparator serves as the second input terminal of the comparator unit, and the output terminal of the comparator serves as the output terminal of the comparator unit; the second diode is connected between the first input terminal and the output terminal of the comparator.

8. The power protection device according to claim 1, characterized in that, Also includes: A protection module is connected to the front end of the power protection device to provide overvoltage protection and / or reverse connection protection for the power supply.

9. A battery management system, characterized in that, include: The power supply, the downstream load, and the power protection device as described in any one of claims 1-8; wherein the power protection device is connected in series between the power supply and the downstream load.

10. The battery management system according to claim 9, characterized in that, The downstream load includes at least one of a power device, a drive device, and a control device; the power supply branch of the power device is a power branch, the power supply branch of the drive device is a drive branch, and the power supply branch of the control device is a control branch. The power protection device is connected in series in the power branch, in series in the drive branch, and / or in series in the control branch.

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