Power supply protection device and battery management system

Abstract

The invention discloses a power supply protection device and a battery management system. The power supply protection device comprises a first switch module through which a power supply supplies power to a post-stage load; a voltage difference exists between the control end and the first end of the second switch module; the second switch module is used for charging the control end of the first switch module in a conducting state so as to control the first switch module to be conducted; a voltage difference exists between the control end and the first end of the third switch module; the third switch module is used for controlling the first switch module to be switched off when the device exceeds the set voltage and limiting the current increase of the first switch module when the current of the post-stage load exceeds the set current; and the comparison module is used for controlling the on-off of the first switch module by controlling the second switch module at a set time interval. According to the embodiment of the invention, the power utilization reliability of the rear-end load is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply protection, and in particular to a power supply protection device and a battery management system. Background Art

[0002] During the operation or debugging of the battery management system, the downstream loads are often plugged in and out while powered on, connected incorrectly, short-circuited, and connected in reverse. Since the downstream loads lack protection devices, plugging and unplugging while powered on can easily cause arcing and flashing of the downstream loads, and wrong wiring can cause the downstream loads to short-circuit and burn or even be scrapped, which seriously affects the debugging and development progress. Therefore, the power supply provided by the prior art has poor reliability when supplying power to the downstream loads. Summary of the invention

[0003] The present invention provides a power supply protection device and a battery management system to solve the problem of poor reliability of power consumption of subsequent loads.

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

[0005] a first switch module, wherein a first end and a second end of the first switch module are connected in series between a power supply end and a subsequent load, and a voltage difference exists between a control end and a first end of the first switch module; and the power supply supplies power to the subsequent load through the first switch module;

[0006] a voltage dividing module and a second switch module, wherein the control end of the second switch module is electrically connected to the power supply end through the voltage dividing module, the first end of the second switch module is electrically connected to the reference voltage end, the second end of the second switch module is electrically connected to the control end of the first switch module, and an upper limit clamp of the voltage difference exists between the control end and the first end of the second switch module; the second switch module is used to charge the control end of the first switch module in a conducting state to control the first switch module to conduct;

[0007] a third switch module, wherein a first end of the third switch module is electrically connected to the power supply end, a second end of the third switch module is electrically connected to a control end of the first switch module, a control end of the third switch module is electrically connected to a first end of the first switch module, and a voltage difference exists between the control end and the first end 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 subsequent load exceeds a set current;

[0008] A comparison module, wherein a first end of the comparison module is electrically connected to the power supply end, a second end of the comparison module is electrically connected to the second end of the third switch module, and a third end of the comparison module is electrically connected to the control end of the second switch module; the comparison module is used to control the on and off of the first switch module by controlling the second switch module at a set time interval.

[0009] Optionally, the first switch module includes a first switch tube, a first resistor and a first voltage regulator tube;

[0010] The control electrode of the first switch tube serves as the control end of the first switch module, the first electrode of the first switch tube serves as the first end of the first switch module, and the second electrode of the first switch tube serves as the second end of the first switch module;

[0011] The first resistor is connected between the control electrode and the first electrode of the first switch tube;

[0012] The positive electrode of the first voltage regulator tube is electrically connected to the control electrode of the first switch tube, and the negative electrode of the first voltage regulator tube is electrically connected to the first electrode of the first switch tube.

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

[0014] And / or, the second switch module includes: a second switch tube, a third resistor, a fourth resistor, a fifth resistor and a second voltage regulator tube;

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

[0016] The positive electrode of the second voltage regulator tube is electrically connected to the second electrode of the second switch tube, and the negative electrode of the second voltage regulator tube is electrically connected to the control electrode of the second switch tube.

[0017] Optionally, the third switch module includes:

[0018] A third switch tube, wherein the first electrode of the third switch tube serves as the first end of the third switch module, and the second electrode of the third switch tube serves as the second end of the third switch module;

[0019] a first control branch, wherein a first end of the first control branch is electrically connected to a control electrode of the third switch tube, and the first control branch is used to control the third switch tube to be turned on when the device exceeds the set voltage;

[0020] A second control branch, wherein the first end of the second control branch is electrically connected to the control electrode of the third switch tube, the second end of the second control branch is electrically connected to the first electrode of the third switch tube, and the third end of the second control branch serves as the control end 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 subsequent load exceeds the set current.

[0021] Optionally, the first control branch includes a sixth resistor and a third voltage regulator tube connected in series between the control electrode of the third switch tube and the reference voltage terminal; wherein the positive electrode of the third voltage regulator tube is electrically connected to the reference voltage terminal, and the negative electrode of the third voltage regulator tube is connected to the control electrode of the third switch tube 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] a first input unit, wherein a first end of the first input unit serves as a first end of the comparison module, a second end of the first input unit is electrically connected to the reference voltage end, and the first input unit is used to divide the voltage between the first end and the second end and output it through the third end;

[0025] a second input unit, wherein a first end of the second input unit serves as a second end of the comparison module, a second end of the second input unit is electrically connected to the reference voltage end, and the second input unit is used to be charged by the third switch module to control the voltage of the third end thereof to intermittently change at a set interval;

[0026] A comparator unit, wherein a first input terminal of the comparator unit is electrically connected to a third terminal of the first input unit, a second input terminal of the comparator unit is electrically connected to a third terminal of the second input unit, and an output terminal of the comparator unit serves as a third terminal of the comparison module.

[0027] Optionally, the first input unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a fourth voltage regulator 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 voltage regulator 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 voltage-stabilizing diode and a second capacitor; the twelfth resistor serves as a first end of the second input unit, the second end of the twelfth resistor serves as a third end of the second input unit, the first end of the thirteenth resistor is electrically connected to the second end of the twelfth resistor, and the second end of the thirteenth resistor serves as a second end of the second input unit; the fifth voltage-stabilizing diode is connected in parallel to both ends of the thirteenth resistor; and the second capacitor is connected in parallel to both ends of the thirteenth resistor;

[0029] And / or, the comparator unit includes a comparator and a second diode, the first input end of the comparator serves as the first input end of the comparator unit, the second input end of the comparator serves as the second input end of the comparator unit, and the output end of the comparator serves as the output end of the comparator unit; the second diode is connected between the first input end and the output end 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 perform overvoltage protection and / or reverse connection protection on the power supply.

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

[0033] Optionally, the subsequent 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] Wherein, the power supply protection device is respectively 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 by the embodiment of the present invention is that when the power supply supplies power to the subsequent load, the first switch module defaults to the off state, and by setting the second switch module to charge the first switch module, the first switch module is gradually turned on, so that the current flowing into the capacitor in the subsequent load is gradually increased, thereby avoiding the problem of arc flashover caused by excessive current surge due to the sudden change of the capacitor voltage in the subsequent load at the moment of power supply. By setting the third switch module, when the current flowing into the subsequent load from the first switch module exceeds the set current, the conduction degree of the first switch module can be limited, so that the current can be maintained in a stable state, the arc current is suppressed, and the arc energy is limited. And when the power protection device is over-voltage, the third switch module can disconnect the first switch module, so that the subsequent load is protected from excessive voltage, thereby improving the reliability of the power protection device. By setting the comparison module, the heating protection of the first switch module is realized. In summary, the embodiments of the present invention realize power supply protection for the subsequent load, avoid overcurrent and overvoltage of the subsequent load, prevent arcing and flashover of the capacitor in the subsequent load caused by sudden changes in voltage or current, and improve the reliability of power use.

[0036] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

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

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

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

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

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

[0043] Figure 6 It is a structural schematic diagram of a battery management system provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 described embodiments 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 creative work 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 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 data 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 that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0046] An embodiment of the present invention provides a power supply protection device. Figure 1 A schematic diagram of the structure of a power supply protection device provided by an embodiment of the present invention. Figure 1The power supply 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 comparison module 5. The first end and the second end of the first switch module 1 are connected in series between the power supply end and the subsequent load 6, and there is a voltage difference between the control end and the first end of the first switch module 1; the power supply supplies power to the subsequent load 6 through the first switch module 1. The control end of the second switch module 2 is electrically connected to the power supply end through the voltage divider module 4, and the first end of the second switch module 2 is electrically connected to the reference voltage end. For example, the reference voltage end can be a ground end. The second end of the second switch module 2 is electrically connected to the control end of the first switch module 1, and there is a voltage difference upper limit clamp between the control end and the first end of the second switch module 2; the second switch module 2 is used to charge the control end of the first switch module 1 in the on state to control the first switch module 1 to be turned on. The first end of the third switch module 3 is electrically connected to the power supply end, the second end of the third switch module 3 is electrically connected to the control end of the first switch module 1, the control end of the third switch module 3 is electrically connected to the first end of the first switch module 1, and there is a voltage difference between the control end and the first end 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 the set voltage, and to limit the current increase of the first switch module 1 when the current of the subsequent load 6 exceeds the set current. The first end of the comparison module 5 is electrically connected to the power supply end, the second end of the comparison module 5 is electrically connected to the second end of the third switch module 3, and the third end of the comparison module 5 is electrically connected to the control end of the second switch module 2; the comparison module 5 is used to control the on and off of the first switch module 1 by controlling the second switch module 2 at a set time interval.

[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, the first end and the second end of the third switch module 3 and the first switch module 1 are not connected, and the subsequent load 6 is not powered, so that the capacitor in the subsequent load 6 will not generate a current surge due to instantaneous access to the power supply. The problem of arc flashover of the capacitor at the moment of power supply is avoided.

[0048] At the same time, the power supply supplies power to the second switch module 2 through the voltage divider module 4, so that the control end and the first end of the second switch module 2 are turned on due to the voltage difference. There is an upper limit clamp of the voltage difference between the control end and the first end of the second switch module 2, which can be used to limit the voltage difference between the control end and the first end of the second switch module 2 to prevent 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 end of the first switch module 1 through the second switch module 2. When the voltage difference between the control end and the first end of the first switch module 1 reaches the turn-on voltage of the first switch module 1, the first switch module 1 is gradually turned on. As the voltage difference between the control end and the first end continues to increase, the conduction degree of the first switch module 1 also continues to increase, so that the current flowing into the first switch module 1 gradually increases.

[0049] When the current flowing into the subsequent load 6 through the first switch module 1 continues to increase and exceeds the set current value, the current flowing through the third switch module 3 also gradually increases, so that the voltage difference between the control end and the first end of the third switch module 3 gradually increases, and the conduction degree of the third switch module 3 also continues to increase. At this time, the second end of the third switch module 3 outputs a larger current, thereby increasing the potential at the connection between the second switch module 2 and the first switch module 1. Therefore, the voltage difference between the control end and the first end of the first switch module 1 is reduced, and the conduction degree of the first switch module 1 is reduced, which limits the increase in the current of the first switch module 1, thereby limiting the arcing energy of the capacitor in the subsequent load 6. When a short-circuit fault occurs in the subsequent load 6, the short-circuit current will also be limited because the current of the first switch 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 is disconnected to protect the subsequent load 6 from excessive voltage.

[0051] Since the first switch module 1 is in a semi-conducting state, the first switch module 1 will be subjected to certain thermal stress due to heat generation during operation. The comparison module 5 can intermittently control the on and off of the first switch module 1, thereby reducing the heat generation of the first switch module 1.

[0052] The technical solution provided by the embodiment of the present invention is that when the power supply supplies power to the subsequent load 6, the first switch module 1 defaults to the off state, and the second switch module 2 is set to charge the first switch module 1, so that the first switch module 1 is gradually turned on, so that the current flowing into the capacitor in the subsequent load 6 is gradually increased, thereby avoiding the problem of arc flashover caused by excessive current surge due to the sudden change of the capacitor voltage in the subsequent load 6 at the moment of power supply. By setting the third switch module 3, when the current flowing into the subsequent load 6 from the first switch module 1 exceeds the set current, the conduction degree of the first switch module 1 can be limited, so that the current can be maintained in a stable state, the arc current is suppressed, and the arc energy is limited. And when the power protection device is over-voltage, the third switch module 3 can disconnect the first switch module 1, so that the subsequent load 6 is protected from excessive voltage, thereby improving the reliability of the power protection device. By setting the comparison module 5, the heating protection of the first switch module 1 is realized. In summary, the embodiment of the present invention realizes power supply protection for the subsequent load 6, avoids overcurrent and overvoltage of the subsequent load 6, prevents arcing and flashover caused by sudden changes in voltage or current of the capacitor in the subsequent load 6, and improves the reliability of power use.

[0053] Figure 2 A schematic diagram of the structure of another power supply protection device provided by an embodiment of the present invention. Figure 2 On the basis of the above embodiments, optionally, the first switch module includes a first switch tube Q1, a first resistor R1 and a first voltage regulator tube VD1. The control electrode of the first switch tube Q1 serves as the control end of the first switch module 1, the first electrode of the first switch tube Q1 serves as the first end of the first switch module 1, and the second electrode of the first switch tube Q1 serves as the second end of the first switch module 1; the first resistor R1 is connected between the control electrode and the first electrode of the first switch tube Q1; the positive electrode of the first voltage regulator tube VD1 is electrically connected to the control electrode of the first switch tube Q1, and the negative electrode of the first voltage regulator tube VD1 is electrically connected to the first electrode of the first switch tube Q1.

[0054] The first resistor R1 is connected between the control electrode and the first electrode of the first switch tube Q1. When current flows through the first resistor R1, voltage will be generated across the first resistor R1. By connecting the first voltage regulator tube VD1 in parallel across the first resistor R1, the voltage across the first resistor R1 can be limited. This is also equivalent to limiting the maximum voltage between the control electrode and the first electrode of the first switch tube Q1, so as to protect the first switch tube Q1 from being damaged by excessive voltage.

[0055] Continue to refer Figure 2On the basis of the above embodiments, optionally, the voltage divider module 4 includes a second resistor R2, a first end of the second resistor R2 serves as the first end of the voltage divider module 4, and a 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 tube Q2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a second voltage regulator tube VD2; wherein, the first end of the third resistor R3 serves as the control end 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 tube 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 tube Q2, the first electrode of the second switch tube 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 tube Q2 is electrically connected to the reference voltage end, and the second electrode of the second switch tube Q2 serves as the first end of the second switch module 2; the positive electrode of the second voltage regulator tube VD2 is electrically connected to the second electrode of the second switch tube Q2, and the negative electrode of the second voltage regulator tube VD2 is electrically connected to the control electrode of the second switch tube.

[0056] The power supply supplies power to the second switch module 2 through the second resistor R2, the loop between the second resistor R2, the third resistor R3 and the fourth resistor R4 is turned on, and a voltage is generated across the fourth resistor R4. The fourth resistor R4 is connected in parallel between the control electrode and the second electrode of the second switch tube Q2, so that the second switch tube Q2 is turned on due to the voltage difference between the control electrode and the second electrode of the second switch tube Q2. The second voltage regulator tube VD2 can be used to limit the voltage between the control electrode and the second electrode of the second switch tube Q2 to prevent the second switch tube Q2 from being damaged due to overvoltage.

[0057] After the second switch tube Q2 is turned on, the first switch tube Q1 can be charged through the first electrode of the second switch tube Q2. When the voltage between the control electrode and the first electrode of the first switch tube Q1 reaches the turn-on voltage, the first switch tube Q1 is gradually turned on, and the power supply supplies power to the subsequent load 6 through the first switch tube Q1. By providing the third diode D3, the current of the second switch tube Q2 can be prevented from flowing back into the third switch module 3.

[0058] Continue to refer Figure 2On the basis of the above embodiments, optionally, the third switch module 3 includes: a third switch tube Q3, a first control branch 31 and a second control branch 32. The first pole of the third switch tube Q3 serves as the first end of the third switch module 3, and the second pole of the third switch tube Q3 serves as the second end of the third switch module 3; the first end of the first control branch 31 is electrically connected to the control pole of the third switch tube Q3, and the first control branch 31 is used to control the third switch tube Q3 to be turned on when the device exceeds the set voltage; the first end of the second control branch 32 is electrically connected to the control pole of the third switch tube Q3, the second end of the second control branch 32 is electrically connected to the first pole of the third switch tube Q3, and the third end of the second control branch 32 serves as the control end of the third switch module 3; the second control branch 32 is used to limit the current increase of the first switch module 1 when the current of the subsequent load 6 exceeds the set current.

[0059] Among them, the first control branch 31 is an overvoltage protection branch. When the voltage input to the first control branch 31 exceeds the set voltage, the third switch tube Q3 is turned on. The third switch tube Q3 has a lower turn-on voltage. Exemplarily, the turn-on voltage can be 0.7V. Therefore, when the third switch tube Q3 is turned on, the voltage between the control electrode and the first electrode of the first switch tube Q1 can be limited to 0.7V. This voltage does not reach the turn-on voltage of the first switch tube Q1, so that the first switch tube Q1 is turned off. At the same time, the first control branch 31 can ground the excessive voltage, so as to prevent the excessive voltage from causing damage to the power protection device.

[0060] The second control branch 32 is an overcurrent protection branch. When the current of the subsequent load 6 continues to increase, the voltage of the second control branch 32 will also increase continuously, so that the conduction degree of the third switch tube Q3 continues to increase. The second electrode of the third switch tube Q3 outputs a larger current, so that the potential of the fifth resistor R5 increases. This is equivalent to reducing the voltage difference between the control electrode and the first electrode of the first switch tube Q1, so that the conduction degree of the first switch tube Q1 is reduced, thereby limiting the current input by the first switch tube Q1 to the subsequent load 6, so that the first switch tube Q1 can be maintained in the constant current region.

[0061] Continue to refer Figure 2On the basis of the above embodiments, optionally, the first control branch 31 includes a sixth resistor R6 and a third voltage regulator tube VD3 connected in series between the control electrode of the third switch tube Q3 and the reference voltage terminal; wherein the positive electrode of the third voltage regulator tube VD3 is electrically connected to the reference voltage terminal, and the negative electrode of the third voltage regulator tube VD3 is connected to the control electrode of the third switch tube 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 the allowable overvoltage value is set to 20%, the third voltage regulator tube VD3 can select a 28V voltage regulator tube. When the on-voltage of the third switch tube Q3 is 0.7V, if the voltage input to the power supply end is greater than 28.7V, the third voltage regulator tube VD3 will be broken down, and the power supply is grounded through the sixth resistor R6 and the third voltage regulator tube VD3, thereby avoiding the impact of excessive voltage on the power protection device. Because the on-voltage of the third switch tube Q3 is 0.7V, the voltage difference between the control electrode and the first electrode of the first switch tube Q1 is also 0.7V, and this voltage value is small and will not turn on the first switch tube Q1.

[0063] The first switch tube Q1 can be a triode. When the first switch tube Q1 is gradually turned on, the current flowing through the seventh resistor R7 also gradually increases. When the voltage drop of the seventh resistor R7 increases to a certain value, the collector junction of the third switch tube Q3 is forward biased, and the base of the third switch tube Q3 flows through the current. The loop of the eighth resistor R8, the first diode D1 and the subsequent load 6 is turned on, thereby turning on the third switch tube Q3. After the third switch tube Q3 is turned on, as the current flowing through the seventh resistor R7 gradually increases, the conduction degree of the third switch tube Q3 also gradually increases, so that the collector of the third switch tube Q3 outputs a larger current, thereby increasing the potential of the fifth resistor R5. The high potential of the fifth resistor R5 is equivalent to reducing the voltage difference between the control electrode and the first electrode of the first switch tube Q1, so that the conduction degree of the first switch tube Q1 is reduced, thereby limiting the current input to the subsequent load 6 by the first switch tube Q1. At this time, negative feedback is formed, and the first switch tube Q1 is maintained in the constant current region.

[0064] Figure 3 A schematic diagram of the structure of another power supply protection device provided by an embodiment of the present invention. Figure 3On the basis of the above embodiments, optionally, the comparison module 5 includes: a first input unit 51, wherein the first end of the first input unit 51 serves as the first end of the comparison module 5, the second end of the first input unit 51 is electrically connected to the reference voltage end, and the first input unit 51 is used to divide the voltage between the first end and the second end and output it through the third end. A second input unit 52, wherein the first end of the second input unit 52 serves as the second end of the comparison module 5, the second end of the second input unit 52 is electrically connected to the reference voltage end, and the second input unit 52 is used to be charged by the third switch module 3 to control the voltage at the third end to change intermittently at a set interval. A comparator unit 53, wherein the first input end of the comparator unit 53 is electrically connected to the third end of the first input unit 51, the second input end of the comparator unit 53 is electrically connected to the third end of the second input unit, and the output end of the comparator unit 53 serves as the third end of the comparison module 5.

[0065] The first input unit 51 can divide the voltage between the first end and the second end thereof, and input the voltage into the first input end of the comparator unit 53, which can be a non-inverting input end. When the third switch tube Q3 is turned on, the second input unit 52 starts to charge, and inputs the charging voltage into the second input end of the comparator unit 53. When the charging voltage does not reach the voltage of the first input end of the comparator unit 53, the comparator unit 53 outputs a high level, and the second switch tube Q2 remains turned on. When the charging voltage reaches the voltage of the first input end of the comparator unit 53, the comparator unit 53 reverses to a low level, turning off the second switch tube Q2, thereby turning off the first switch tube Q1, and also turning off the third switch tube Q3. At this time, the first input end of the comparator unit 53 has a smaller input voltage, and at the same time, the second input unit 52 starts to discharge to the second input end of the comparator unit 53, which can be a reverse input end. When the discharge voltage reaches the voltage of the first input terminal of the comparator unit 53, the comparator unit 53 outputs a high level, so that the second switch tube Q2 is turned on, and then the first switch tube Q1 is turned on, so that the first switch tube Q1 continues to operate. The embodiment of the present invention realizes the intermittent conduction and shutdown of the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3, reduces the thermal stress of the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3, reduces the selection requirements of the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3, and reduces the cost of the power protection device.

[0066] Continue to refer Figure 3On the basis of the above embodiments, optionally, the first input unit 51 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a fourth voltage regulator 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 voltage regulator 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 voltage regulator VD4 can be a 5V voltage regulator, and the tenth resistor R10 and the eleventh resistor R11 are set to have the same resistance. The tenth resistor R10 and the eleventh resistor R11 each receive a 2.5V voltage and input it 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 voltage regulator tube VD5 and a second capacitor C2; the twelfth resistor R12 serves as the first end of the second input unit, the second end of the twelfth resistor R12 serves as the third end of the second input unit, the first end of the thirteenth resistor R13 is electrically connected to the second end of the twelfth resistor R12, and the second end of the thirteenth resistor R13 serves as the second end of the second input unit 52; the fifth voltage regulator tube VD5 is connected in parallel to both ends of the thirteenth resistor R13; the second capacitor C2 is connected in parallel to both ends of the thirteenth resistor R13. The comparator unit 53 includes a comparator U1 and a second diode D2, the first input end of the comparator U1 serves as the first input end of the comparator unit 53, the second input end of the comparator U1 serves as the second input end of the comparator unit 53, and the output end of the comparator U1 serves as the output end of the comparator unit 53; the second diode D2 is connected between the first input end and the output end of the comparator U1.

[0069] The fifth voltage regulator tube VD5 is used for clamping, which can prevent the second input terminal of the comparator U1 from being damaged by inputting an excessive voltage. When the third switch tube Q3 is turned on, the second capacitor C2 starts to charge. When the charging voltage of the second capacitor C2 does not reach 2.5V, the comparator U1 outputs a high level, and the second switch tube Q2 remains turned on. When the charging voltage of the second capacitor C2 reaches 2.5V, the comparator U1 reverses to a low level, and the second switch tube Q2 is turned off.

[0070] After the second switch tube Q2 is turned off, illustratively, when the conduction voltage of the second diode D2 is 0.7 V, the voltage of the first input terminal of the comparator U1 becomes 0.7 V. The second capacitor C2 starts to discharge, and due to the provision of the fourth diode D4, the discharge loop of the second capacitor C2 only has the thirteenth resistor R13, and when the voltage of the thirteenth resistor R13 reaches 0.7 V, the comparator U1 reverses to a high level, and the first switch tube Q1, the second switch tube Q2, and the third switch tube Q3 are gradually turned on again.

[0071] Figure 4 A schematic diagram of the structure of another power supply protection device provided by an embodiment of the present invention. Figure 4 On the basis of 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 perform overvoltage protection and / or reverse connection protection on the power supply.

[0072] The protection module 7 includes a fuse F1, a sixth voltage regulator tube VD6 and a seventh voltage regulator tube VD7. In other embodiments, the fuse F1 may also be a fuse, and the sixth voltage regulator tube VD6 and the seventh voltage regulator tube VD7 may also be TVS tubes (TRANSIENT VOLTAGE SUPPRESSOR, transient voltage suppression diodes).

[0073] Exemplarily, when the maximum withstand voltage of all components of the power protection device can withstand 100V, the breakdown voltage of the sixth voltage regulator tube VD6 and the seventh voltage regulator tube VD7 can be selected to be a voltage regulator tube of about 80V. If the maximum withstand voltage value is 50V, the breakdown voltage of the sixth voltage regulator tube VD6 and the seventh voltage regulator tube VD7 can be selected to be a voltage regulator tube of about 40V, which can be set specifically according to design requirements. Compared with setting one voltage regulator tube, setting the sixth voltage regulator tube VD6 and the seventh voltage regulator tube VD7 in parallel can increase the breakdown current capacity. The fuse F1 can select the highest voltage of the power protection device to ensure that any voltage of the power supply connected to the power protection device can protect the subsequent load 6, effectively preventing damage to the subsequent load 6.

[0074] The sixth voltage regulator tube VD6 and the seventh voltage regulator tube VD7 are both unidirectional conducting voltage regulator tubes. When the power supply is reversely connected, the sixth voltage regulator tube VD6 and the seventh voltage regulator tube VD7 have a lower conduction voltage, thereby realizing the protection of the power supply protection device. Even if the reverse input voltage is too large, the fuse F1 will melt, thereby cutting off the power supply.

[0075] Figure 5 This is a voltage simulation diagram of a power protection device provided by an embodiment of the present invention. 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. Figure 5 As shown, when the power protection device is connected to the voltage, the first switch tube 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 tube is gradually turned 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 voltage maximum value, the first switch tube is disconnected, and the output voltage Vout of the power protection device is 0.

[0076] An embodiment of the present invention also provides a battery management system. Figure 6 A schematic diagram of the structure of a battery management system provided by an embodiment of the present invention. Figure 6 The battery management system comprises: a power supply, a subsequent load 6 and a power protection device 10 provided by any embodiment of the present invention; wherein the power protection device 10 is connected in series between the power supply and the subsequent load 6. The battery management system has similar beneficial effects as the power protection device provided by any of the above embodiments, which will not be described in detail here.

[0077] Continue to refer Figure 6 On the basis of the above embodiments, optionally, the post-stage 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 supply protection device 10 is respectively connected in series in the power branch, in series in the drive branch, and / or in series in the control branch.

[0078] Among them, there are multiple power supply branches in the battery management system. If the power supply protection device 10 is not set, when a device in one of the power supply branches fails such as a short circuit, the voltage of all power supply branches will drop, thereby affecting the normal operation of the entire battery management system. The embodiment of the present invention connects the power supply protection device 10 in series in each power supply branch. When a power supply branch fails, the power supply protection device 10 will limit the current and voltage in the power supply branch so that it will not affect other power supply branches, thereby improving the reliability of the battery management system.

[0079] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0080] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A power supply protection device, characterized in that: include: a first switch module, wherein a first end and a second end of the first switch module are connected in series between a power supply end and a subsequent load, and a voltage difference exists between a control end and a first end of the first switch module; and the power supply supplies power to the subsequent load through the first switch module; a voltage dividing module and a second switch module, wherein the control end of the second switch module is electrically connected to the power supply end through the voltage dividing module, the first end of the second switch module is electrically connected to the reference voltage end, the second end of the second switch module is electrically connected to the control end of the first switch module, and an upper limit clamp of the voltage difference exists between the control end and the first end of the second switch module; the second switch module is used to charge the control end of the first switch module in a conducting state to control the first switch module to conduct; a third switch module, wherein a first end of the third switch module is electrically connected to the power supply end, a second end of the third switch module is electrically connected to a control end of the first switch module, a control end of the third switch module is electrically connected to a first end of the first switch module, and a voltage difference exists between the control end and the first end 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 subsequent load exceeds a set current; A comparison module, wherein a first end of the comparison module is electrically connected to the power supply end, a second end of the comparison module is electrically connected to the second end of the third switch module, and a third end of the comparison module is electrically connected to the control end of the second switch module; the comparison module is used to control the on and off 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 switch module includes a first switch tube, a first resistor and a first voltage regulator tube; The control electrode of the first switch tube serves as the control end of the first switch module, the first electrode of the first switch tube serves as the first end of the first switch module, and the second electrode of the first switch tube serves as the second end of the first switch module; The first resistor is connected between the control electrode and the first electrode of the first switch tube; The positive electrode of the first voltage regulator tube is electrically connected to the control electrode of the first switch tube, and the negative electrode of the first voltage regulator tube is electrically connected to the first electrode of the first switch tube.

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

4. The power protection device according to claim 1, characterized in that: The third switch module comprises: A third switch tube, wherein the first electrode of the third switch tube serves as the first end of the third switch module, and the second electrode of the third switch tube serves as the second end of the third switch module; a first control branch, wherein a first end of the first control branch is electrically connected to a control electrode of the third switch tube, and the first control branch is used to control the third switch tube to be turned on when the device exceeds the set voltage; A second control branch, wherein the first end of the second control branch is electrically connected to the control electrode of the third switch tube, the second end of the second control branch is electrically connected to the first electrode of the third switch tube, and the third end of the second control branch serves as the control end 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 subsequent load exceeds the 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 voltage regulator tube connected in series between the control electrode of the third switch tube and the reference voltage terminal; wherein the positive electrode of the third voltage regulator tube is electrically connected to the reference voltage terminal, and the negative electrode of the third voltage regulator tube is connected to the control electrode of the third switch tube 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 comprises: a first input unit, wherein a first end of the first input unit serves as a first end of the comparison module, a second end of the first input unit is electrically connected to the reference voltage end, and the first input unit is used to divide the voltage between the first end and the second end and output it through the third end; a second input unit, wherein a first end of the second input unit serves as a second end of the comparison module, a second end of the second input unit is electrically connected to the reference voltage end, and the second input unit is used to be charged by the third switch module to control the voltage of the third end thereof to intermittently change at a set interval; A comparator unit, wherein a first input terminal of the comparator unit is electrically connected to a third terminal of the first input unit, a second input terminal of the comparator unit is electrically connected to a third terminal of the second input unit, and an output terminal of the comparator unit serves as a 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 voltage regulator 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 voltage regulator is connected between the second end of the ninth resistor and the reference voltage end, and the first capacitor is connected between the second end of the tenth resistor and the reference voltage end; And / or, the second input unit includes a twelfth resistor, a thirteenth resistor, a fifth voltage-stabilizing diode and a second capacitor; the twelfth resistor serves as a first end of the second input unit, the second end of the twelfth resistor serves as a third end of the second input unit, the first end of the thirteenth resistor is electrically connected to the second end of the twelfth resistor, and the second end of the thirteenth resistor serves as a second end of the second input unit; the fifth voltage-stabilizing diode is connected in parallel to both ends of the thirteenth resistor; and the second capacitor is connected in parallel to both ends of the thirteenth resistor; And / or, the comparator unit includes a comparator and a second diode, the first input end of the comparator serves as the first input end of the comparator unit, the second input end of the comparator serves as the second input end of the comparator unit, and the output end of the comparator serves as the output end of the comparator unit; the second diode is connected between the first input end and the output end 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 perform overvoltage protection and / or reverse connection protection on the power supply.

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

10. The battery management system according to claim 9, characterized in that: The latter load comprises: 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; Wherein, the power supply protection device is respectively 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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