A fault detection device and method for a charge-discharge MOS tube

Abstract

The application relates to a fault detection device and method of a charge-discharge MOS tube, which comprises a detection circuit and a discharge MOS control module. One end of the detection circuit is a voltage detection end, and the other end is used for electrically connecting with a power load total negative end. The discharge MOS control module comprises a first short-circuit detection circuit and a first open-circuit detection circuit. The conduction current inflow end of a first switch tube of the first short-circuit detection circuit is connected with a high level through a third resistance branch. A second resistance branch is electrically connected between the high level and the control end of the first switch tube, and the control end serves as a vehicle key signal detection end. The first open-circuit detection circuit comprises a discharge MOS tube. The source is used for electrically connecting with a battery pack total negative end, and the gate serves as a discharge control end. Through the fault detection device of the application, the voltage of the voltage detection end under the corresponding condition is detected by controlling the input of the vehicle key signal detection end and the discharge control end, so that the short-circuit detection and the open-circuit detection of the discharge MOS are completed.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a fault detection device and method for charging and discharging MOSFETs. Background Technology

[0002] An electric vehicle controller is a core vehicle controller. Its design fully considers the relationship between the battery, controller, and motor, treating them as a comprehensive system to achieve a more ideal electric vehicle controller. An electric vehicle controller typically consists of a regulated power supply circuit, a PWM generation circuit, a motor drive circuit, a battery discharge indicator circuit, and motor overcurrent and battery overdischarge protection circuits. Simply put, the motor in the electric vehicle controller is driven by the output current of a MOSFET. The higher the output current (the controller has current limiting protection to prevent overcurrent damage to the MOSFET), the stronger the motor torque and the more powerful the acceleration.

[0003] MOSFETs can be damaged due to various external factors, affecting the safety of electric vehicle charging and discharging. These damages can include overcurrent (high temperature caused by continuous high current or a sudden surge of ultra-high current leading to junction temperature exceeding tolerance), overvoltage (the voltage between the source and drain exceeds the breakdown voltage), gate breakdown (generally caused by external factors or damage to the drive circuit causing the gate voltage to exceed the maximum allowable voltage, typically below 20V for safety), and electrostatic discharge (ESD). Currently, mechanical multimeters are commonly used to measure the resistance between the source and drain, gate and source, and gate and drain of the MOSFET, comparing this resistance to the values ​​specified in the MOSFET datasheet to determine its condition.

[0004] Therefore, there is a need to provide a fault detection device for charging and discharging MOSFETs that can promptly detect MOSFET faults and issue alarms, effectively ensure the charging and discharging safety performance of electric vehicles, and has a simple and easy-to-implement detection process to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a fault detection device for charging and discharging MOSFETs. This solves the technical problems of existing technologies where faults in the charging and discharging MOSFETs of electric vehicles cannot be detected in a timely manner, and the daily fault detection process is cumbersome.

[0006] The technical effects of this invention are achieved through the following:

[0007] A fault detection device for a charging / discharging MOSFET, applied to the battery management system of an electric vehicle, comprising:

[0008] The detection circuit includes a first resistor branch and a diode. The first resistor branch is connected in series with the diode through the positive terminal. The end of the first resistor branch furthest from the diode is the voltage detection terminal, and the negative terminal of the diode is electrically connected to the negative terminal of the power load. The discharge MOS control module includes a first short-circuit detection circuit and a first open-circuit detection circuit. The first short-circuit detection circuit includes a first switching transistor, a second resistor branch, and a third resistor branch. The current-carrying terminal of the first switching transistor is connected to a high level through the third resistor branch. The second resistor branch is electrically connected between the high level and the control terminal, which serves as the car key signal detection terminal. The current-carrying terminal of the first switching transistor is electrically connected to the positive terminal of the diode. The first open-circuit detection circuit includes a discharge MOS transistor. The drain of the discharge MOS transistor is electrically connected to the negative terminal of the diode, the source is electrically connected to the negative terminal of the battery pack, and the gate serves as the discharge control terminal. The charge / discharge MOS transistor... The fault detection device for the discharge MOSFET is used to control the input of a low level at the car key signal detection terminal when a car key signal is detected, thereby detecting the short circuit of the discharge MOSFET based on the level of the detection voltage detection terminal, and to control the input of a high level at the discharge control terminal, thereby detecting the open circuit of the discharge MOSFET based on the level of the detection voltage detection terminal. By proposing the fault detection device for the charge / discharge MOSFET of this application, when a car key insertion or removal signal is detected, a low level is controlled at the car key signal detection terminal, thereby determining whether a short circuit has occurred in the discharge MOSFET based on the level of the detection voltage detection terminal. When it is determined that the discharge MOSFET is not short-circuited, a high level is controlled at the discharge control terminal, and then the level of the detection voltage detection terminal is used to determine whether an open circuit has occurred in the discharge MOSFET. This achieves both short-circuit and open-circuit detection of the discharge MOSFET, improving the discharge protection performance of electric vehicles.

[0009] Furthermore, it also includes a charging MOS control module, which includes a second short-circuit detection circuit. The second short-circuit detection circuit includes a second switching transistor, a fourth resistor branch, and a fifth resistor branch. The inflow terminal of the second switching transistor is connected to a high level through the fifth resistor branch. The fourth resistor branch is electrically connected between the high level and the control terminal of the second switching transistor. The control terminal serves as a charging signal detection terminal. The outflow terminal of the second switching transistor is electrically connected to the positive terminal of the diode. The fault detection device of the charging and discharging MOS transistor is used to control the charging signal detection terminal to input a low level when a charging signal is detected, so as to detect the level of the voltage detection terminal and complete the short-circuit detection of the charging MOS. Furthermore, the charging MOS control module also includes a second open-circuit detection circuit. This second open-circuit detection circuit includes a charging MOS transistor. The drain of the charging MOS transistor is electrically connected to the negative terminal of the diode, the source is electrically connected to the overall negative terminal of the charger, and the gate serves as the charging control terminal. The fault detection device for the charging / discharging MOS transistor is used to control the charging control terminal to input a high level after completing the short-circuit detection of the charging MOS transistor, thereby detecting the open circuit of the charging MOS transistor based on the level of the detection voltage terminal. By proposing the fault detection device for the charging / discharging MOS transistor of this application, when a charging signal is detected, a low level is controlled at the charging signal detection terminal, thereby determining whether a short circuit has occurred in the charging MOS transistor based on the level of the detection voltage terminal. When it is determined that no short circuit has occurred in the charging MOS transistor, a high level is controlled at the charging control terminal, and then the level of the detection voltage terminal is used to determine whether an open circuit has occurred in the charging MOS transistor. This achieves both short-circuit and open-circuit detection of the charging MOS transistor, improving the charging protection performance of electric vehicles.

[0010] Furthermore, the first switching transistor and the second switching transistor are PNP transistors or P-MOS transistors.

[0011] Furthermore, a voltage regulator circuit is provided at the voltage detection terminal, which is used to regulate the voltage level at the voltage detection terminal.

[0012] In addition, a fault detection method for a charging and discharging MOSFET is provided. The method is based on the above-mentioned fault detection device for a charging and discharging MOSFET and includes: when a car key insertion signal or a car key removal signal is detected, controlling the car key signal detection terminal to input a low level so as to turn on the first switching transistor.

[0013] The system detects whether the voltage at the voltage detection terminal is low; if so, it determines that the discharge MOSFET is short-circuited and outputs a corresponding alarm signal. Further, the system detects whether the voltage at the voltage detection terminal is low, and then: if not, it controls the discharge control terminal to input a high level to turn on the discharge MOSFET; and then detects the voltage at the voltage detection terminal.

[0014] If the voltage at the voltage detection terminal is high, it is determined that the discharge MOS transistor is open, and a corresponding alarm signal is output.

[0015] If the voltage at the voltage detection terminal is low, the discharge MOS transistor is considered to be functioning normally.

[0016] Furthermore, it also includes:

[0017] When the discharge MOSFET is off, a low level is input to the charging signal detection terminal when a charging signal is detected, so that the second switch is turned on.

[0018] The system detects whether the voltage at the voltage detection terminal is low; if so, it determines that the charging MOSFET is short-circuited and outputs a corresponding alarm signal. Further, the system detects whether the voltage at the voltage detection terminal is low, and then: if not, it controls the discharge control terminal to input a high level to turn on the charging MOSFET; and then detects the voltage at the voltage detection terminal.

[0019] If the voltage at the voltage detection terminal is high, it is determined that the charging MOSFET is open-circuited, and a corresponding alarm signal is output.

[0020] If the voltage at the voltage detection terminal is low, the charging MOSFET is considered to be functioning normally. By automatically completing the corresponding discharge MOSFET detection process or charging MOSFET detection process when a key insertion signal, key removal signal, or charging signal is detected, an early warning can be issued when a short circuit or other abnormal situation is detected, thus improving the safety protection performance of the electric vehicle.

[0021] As described above, the present invention has the following beneficial effects: 1) By proposing the fault detection device for the charging and discharging MOS transistor, when a car key insertion signal or removal signal is detected, a low level is input to the car key signal detection terminal, thereby determining whether the discharge MOS transistor is short-circuited based on the level of the detection voltage detection terminal. When it is determined that the discharge MOS transistor is not short-circuited, a high level is input to the discharge control terminal, and then the level of the detection voltage detection terminal is used to determine whether the discharge MOS transistor is open-circuited, thereby realizing short-circuit detection and open-circuit detection of the discharge MOS transistor and improving the discharge protection performance of electric vehicles.

[0022] 2) By proposing the fault detection device for the charging and discharging MOSFET of this application, when a charging signal is detected, the charging signal detection terminal is controlled to input a low level, thereby determining whether the charging MOSFET is short-circuited based on the level of the detection voltage detection terminal. When it is determined that the charging MOSFET is not short-circuited, the charging control terminal is controlled to input a high level, and then the level of the detection voltage detection terminal is used to determine whether the charging MOSFET is open-circuited. This realizes the short-circuit detection and open-circuit detection of the charging MOSFET, thereby improving the charging protection performance of electric vehicles.

[0023] 3) When a key insertion signal or key removal signal is detected, or a charging signal is detected, the corresponding discharge MOS detection process or charging MOS detection process is automatically completed. This allows an early warning to be issued when a short circuit or other abnormal situation is detected, thereby improving the safety protection performance of electric vehicles.

[0024] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0026] Figure 1 is a circuit diagram of a fault detection device for a charging and discharging MOS transistor provided in an embodiment of this specification;

[0027] Figure 2 is a flowchart illustrating a fault detection method for a charging / discharging MOSFET according to an embodiment of this specification. The reference numerals in the figure correspond to:

[0028] Detection circuit 1, first resistor branch 11, diode 12, discharge MOS control module 2, first short circuit detection circuit 21, first switch 211, second resistor branch 212, third resistor branch 213, first open circuit detection circuit 22, discharge MOS transistor 221, charging MOS control circuit 3, second short circuit detection circuit 31, second switch 311, fourth resistor branch 312, fifth resistor branch 313, second open circuit detection circuit 32, charging MOS transistor 321, voltage regulator circuit 4; Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0030] 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. Example 1:

[0031] As shown in Figure 1, this embodiment of the specification provides a fault detection device for a charging / discharging MOSFET, applied to the battery management system of an electric vehicle. It includes: a detection circuit 1, comprising a first resistor branch 11 and a diode 12. The first resistor branch 11 is connected in series with the diode 12 via its positive terminal. The end of the first resistor branch 11 furthest from the diode 12 is a voltage detection terminal, and the negative terminal of the diode 12 is electrically connected to the negative terminal of the power load. A discharge MOSFET control module 2 includes a first short-circuit detection circuit 21 and a first open-circuit detection circuit 22. The first short-circuit detection circuit 21 includes a first switch 211, a second resistor branch 212, and a third resistor branch 213. The current inflow terminal of the first switch 211 is connected to a high level via the third resistor branch 213. The second resistor branch 212 is electrically connected between the high level and the control terminal. The control terminal serves as the vehicle key signal detection terminal. The current outflow terminal of the first switch 211 and the diode 12... The positive terminal is electrically connected; the first open-circuit detection circuit 22 includes a discharge MOSFET 221, the drain of which is electrically connected to the negative terminal of diode 12, the source of which is electrically connected to the negative terminal of the battery pack, and the gate of which serves as the discharge control terminal. The fault detection device for the charge / discharge MOSFET is used to control the input of a low level at the car key signal detection terminal to achieve a short-circuit detection of the discharge MOSFET when a car key signal is detected, and to control the input of a high level at the discharge control terminal to achieve an open-circuit detection of the discharge MOSFET. The discharge MOSFET 221 is an NMOS transistor.

[0032] Specifically, the first switching transistor 211 is a PNP transistor or an NMOS transistor. When the first switching transistor 211 is a PNP transistor, its control terminal, current inflow terminal, and current output terminal are the base, emitter, and collector, respectively; when the first switching transistor 211 is an NMOS transistor, its corresponding control terminal, current inflow terminal, and current output terminal are the gate, drain, and source, respectively. This application uses a PNP transistor as an example for illustration. Specifically, the second resistor branch 212 and the third resistor branch 213 can be a single resistor, or they can be composed of more than one resistor connected in series, parallel, or in a mixed configuration. The resistance values ​​of the multiple resistors can be the same or different. This embodiment uses a single resistor for both the second resistor branch 212 and the third resistor branch 213.

[0033] Specifically, in Figure 1, the DSG_DECT pin is the car key signal detection terminal, the DSG pin is the discharge control terminal, and the Point A pin is the voltage detection terminal. The conduction current in the first switching transistor 211 flows into the terminal connected to a high level of 3.3V through the third resistor branch 213.

[0034] Preferably, the fault detection device for the charging and discharging MOS transistor further includes a charging MOS control module 3. The charging MOS control module 3 includes a second short-circuit detection circuit 31. The second short-circuit detection circuit 31 includes a second switch 311, a fourth resistor branch 312, and a fifth resistor branch 313. The current inflow terminal of the second switch 311 is connected to a high level through the fifth resistor branch 313. The fourth resistor branch 312 is electrically connected between the high level and the control terminal of the second switch 311. The control terminal serves as the charging signal detection terminal. The current outflow terminal of the second switch 311 is electrically connected to the positive terminal of the diode 12. The fault detection device for the charging and discharging MOS transistor is used to control the charging signal detection terminal to input a low level when a charging signal is detected so as to detect the level of the voltage detection terminal and complete the short-circuit detection of the charging MOS. Preferably, the charging MOS control module 3 further includes a second open-circuit detection circuit 32, which includes a charging MOS transistor 321. The drain of the charging MOS transistor 321 is electrically connected to the negative terminal of the diode 12, the source is electrically connected to the negative terminal of the charger, and the gate serves as the charging control terminal. The fault detection device of the charging and discharging MOS transistor is used to control the charging control terminal to input a high level after the short-circuit detection of the charging MOS transistor is completed, so as to detect the level of the voltage detection terminal to complete the open-circuit detection of the charging MOS transistor. The charging MOS transistor 321 is an NMOS transistor.

[0035] Specifically, the second switching transistor 311 is a PNP transistor or an NMOS transistor. When the second switching transistor 311 is a PNP transistor, its control terminal, current inflow terminal, and current output terminal are the base, emitter, and collector, respectively; when the second switching transistor 311 is an NMOS transistor, its corresponding control terminal, current inflow terminal, and current output terminal are the gate, drain, and source, respectively. This application uses a PNP transistor as an example for illustration. Specifically, the fifth resistor branch 313 and the fourth resistor branch 312 can be a single resistor, or they can be composed of more than one resistor connected in series, parallel, or in a mixed configuration. The resistance values ​​of the multiple resistors can be the same or different. This embodiment uses a single resistor for both the fifth resistor branch 313 and the fourth resistor branch 312.

[0036] Specifically, in Figure 1, the CHG_DECT pin is the charging signal detection terminal, and the CHG pin is the charging control terminal. The current flowing into the second switch 311 is connected to a high level of 3.3V through the fifth resistor branch 313.

[0037] It's important to note that existing electric vehicle controllers rely on the output current of MOSFETs for driving; the higher the output current, the stronger the motor torque. However, under prolonged use, MOSFETs can fail due to overcurrent, over-discharge, or gate breakdown. Typically, MOSFET malfunctions are only detected after a fault occurs in the electric vehicle, or during routine checks using a multimeter to determine their normal operating condition. The proper functioning of MOSFETs is crucial for the charging and discharging process, and their proper status must be known before the electric vehicle enters the charging / discharging phase.

[0038] Therefore, this application, by setting up a detection circuit 1 and a discharge MOS control module 2, enables the key signal detection terminal to input a low level when the insertion or removal of the car key is detected. This allows the system to determine whether a short circuit has occurred in the discharge MOS transistor 221 based on the level of the detection voltage detection terminal. Conversely, when it is determined that the discharge MOS transistor 221 is not short-circuited, the discharge control terminal is controlled to input a high level. This, in turn, determines whether the discharge MOS transistor 221 is open-circuited based on the level of the detection voltage detection terminal. This achieves short-circuit and open-circuit detection of the discharge MOS transistor 221, improving the discharge protection performance of the electric vehicle. Initially, both the DSG_DECT and CHG_DECT pins are at a high level, while the DSG and CHG pins are at a low level.

[0039] When the MCU of the electric vehicle detects the car key signal, it controls the corresponding port of the MCU to output a low level to the DSG_DECT pin. The first switch 211 is turned on, and the current flows through the first switch 211 and diode 12, then connects to the negative terminal P- of the power load. At this time, the positive terminal of diode 12 is at a high level, and the Point A pin, which is connected in series with the positive terminal of diode 12 through the first resistor branch 11, should also be at a high level. The car key signal is either the key insertion signal or the key removal signal. If the voltage at the Point A pin is low, it indicates that the discharge MOSFET 221 is short-circuited. This is because only when the discharge MOSFET 221 is short-circuited is the negative terminal P- of the power load electrically connected to the negative terminal B- of the battery pack through the short-circuited discharge MOSFET 221, resulting in a low voltage at the Point A pin.

[0040] If the voltage at the Point A pin is high, it is determined that the discharge MOSFET 221 is not short-circuited, and the open-circuit detection process continues. That is, the DSG pin input is set to high; at this time, the discharge MOSFET 221 is turned on, and according to the circuit principle described above, the voltage at the Point A pin should be low.

[0041] If a high level is detected at the Point A pin, it indicates that the current flows through the first switch 211 and diode 12 to the negative terminal P- of the power load, and the negative terminal P- of the power load is not electrically connected to the negative terminal B- of the battery pack through the discharge MOSFET 221. This means the discharge MOSFET 221 is in an open-circuit state, hence the high level is detected at the Point A pin. It should be noted that this application, by setting up a detection circuit 1 and a charging MOSFET control module 3, enables the charging signal detection terminal to input a low level when a charging signal is detected. This allows the system to determine whether the charging MOSFET 321 is short-circuited based on the level of the detection voltage terminal. Conversely, when it is determined that the charging MOSFET 321 is not short-circuited, the charging control terminal is controlled to input a high level, and the level of the detection voltage terminal is then used to determine whether the charging MOSFET 321 is open-circuited. This achieves short-circuit and open-circuit detection of the charging MOSFET 321, improving the charging protection performance of the electric vehicle. Initially, the CHG_DECT pin input is high, and the CHG pin input is low. When the electric vehicle's MCU detects a charging signal, it controls the corresponding port of the MCU to output a low level to the CHG_DECT pin, and also controls other corresponding ports of the MCU to output a low level to the DSG pin. That is, during the fault detection process of the discharge MOSFET 221, the CHG_DECT pin input is always kept high, and the CHG pin input is kept low. After the fault detection of the discharge MOSFET 221 is completed, the high-level input of the DSG pin needs to be changed to a low-level input to initiate the fault detection process of the charging MOSFET 321.

[0042] When the CHG_DECT pin input is low, the second switch 311 is turned on. The current flows through the second switch 311 and diode 12 and then connects to the negative terminal P- of the power load. At this time, the positive terminal of diode 12 is high, and the Point A pin, which is connected in series with the positive terminal of diode 12 through the first resistor branch 11, should be high.

[0043] If the voltage at the Point A pin is low, the charging MOSFET 321 is considered short-circuited. This is because the charger's negative terminal B- is only electrically connected to the power load's negative terminal P- through the short-circuited charging MOSFET 321 when the charging MOSFET 321 is short-circuited, resulting in a low voltage at the Point A pin.

[0044] If the voltage at the Point A pin is high, it is determined that the charging MOSFET 321 is not short-circuited, and the open-circuit detection process continues. That is, the CHG pin input is set to high, at which point the charging MOSFET 321 is turned on. According to the circuit principle described above, the voltage at the Point A pin should be low.

[0045] If a high level is detected at the Point A pin, it indicates that the current flows through the second switch 311 and diode 12 to the negative terminal P- of the power load, and the negative terminal P- of the power load is not electrically connected to the negative terminal B- of the charger through the charging MOSFET 321. In other words, the charging MOSFET 321 is in an open-circuit state. Therefore, a high level is detected at the Point A pin. Preferably, a voltage regulator circuit 4 is provided at the voltage detection terminal to regulate the voltage level at the voltage detection terminal.

[0046] Specifically, the voltage regulator circuit 4 includes a filter capacitor and a Zener diode, which are connected in parallel. The negative terminal of the Zener diode is electrically connected to the Point A pin, and the positive terminal of the Zener diode is grounded. As shown in Figure 2, this specification provides an embodiment of a fault detection method for a charging / discharging MOSFET. The method is based on the fault detection device for a charging / discharging MOSFET in Embodiment 1, and includes: S100: When a car key insertion signal or a car key removal signal is detected, the car key signal detection terminal is controlled to input a low level to turn on the first switch MOSFET 211; S200: The voltage at the voltage detection terminal is detected to be low; S300: If yes, the discharge MOSFET 221 is determined to be short-circuited, and a corresponding alarm signal is output; S400: If no, the discharge control terminal is controlled to input a high level to turn on the discharge MOSFET 221.

[0047] S500: Voltage detection terminal;

[0048] S600: If the voltage at the voltage detection terminal is high, it is determined that the discharge MOS transistor 221 is open, and a corresponding alarm signal is output.

[0049] S700: If the voltage at the voltage detection terminal is low, then the discharge MOS transistor 221 is considered to be normal.

[0050] In one specific embodiment, the method further includes: when the discharge MOSFET 221 is off, and a charging signal is detected, controlling the charging signal detection terminal to input a low level to turn on the second switch 311; detecting whether the voltage at the voltage detection terminal is low; if so, determining that the charging MOSFET 321 is short-circuited and outputting a corresponding alarm signal; if not, controlling the discharge control terminal to input a high level to turn on the charging MOSFET 321.

[0051] Detect the voltage at the voltage detection terminal;

[0052] If the voltage at the voltage detection terminal is high, it is determined that the charging MOSFET 321 is open, and a corresponding alarm signal is output.

[0053] If the voltage at the voltage detection terminal is low, then the charging MOSFET 321 is considered to be functioning normally. Although the present invention has been described through preferred embodiments, it is not limited to the embodiments described herein, and various changes and modifications can be made without departing from the scope of the invention.

[0054] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0055] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A fault detection device for a charging / discharging MOSFET, applied to the battery management system of an electric vehicle, characterized in that, include: The detection circuit (1) includes a first resistor branch (11) and a diode (12). The first resistor branch (11) is connected in series with the diode (12) through the positive terminal of the diode (12). The end of the first resistor branch (11) away from the diode (12) is the voltage detection terminal. The negative terminal of the diode (12) is used to be electrically connected to the negative terminal of the power load. The discharge MOS control module (2) includes a first short-circuit detection circuit (21) and a first open-circuit detection circuit (22). The first short-circuit detection circuit (21) includes a first switching transistor (211), a second resistor branch (212), and a third resistor branch (213). The current inflow terminal of the first switching transistor (211) is connected to a high level through the third resistor branch (213). The second resistor branch (212) is electrically connected between the high level and the control terminal. The control terminal serves as the car key signal detection terminal. The current outflow terminal of the first switching transistor (211) is electrically connected to the positive terminal of the diode (12). The first open-circuit detection circuit (22) includes a discharge MOS transistor (221). The drain of tube (221) is electrically connected to the negative terminal of diode (12), the source is electrically connected to the negative terminal of the battery pack, and the gate is used as the discharge control terminal. The fault detection device of the charge and discharge MOS tube is used to control the input of the car key signal detection terminal to a low level when the car key signal is detected so as to complete the short circuit detection of the discharge MOS by the level of the detection voltage detection terminal, and to control the input of the discharge control terminal to a high level so as to complete the open circuit detection of the discharge MOS by the level of the detection voltage detection terminal.

2. The fault detection device for a charging / discharging MOS transistor according to claim 1, characterized in that, It also includes a charging MOS control module (3), which includes a second short-circuit detection circuit (31). The second short-circuit detection circuit (31) includes a second switch (311), a fourth resistor branch (312) and a fifth resistor branch (313). The conducting current inflow terminal of the second switch (311) is connected to a high level through the fifth resistor branch (313). The fourth resistor branch (312) is electrically connected between the high level and the control terminal of the second switch (311). The control terminal serves as a charging signal detection terminal. The conducting current outflow terminal of the second switch (311) is electrically connected to the positive terminal of the diode (12). The fault detection device of the charging and discharging MOS tube is used to control the charging signal detection terminal to input a low level when a charging signal is detected so as to detect the level of the voltage detection terminal and complete the short-circuit detection of the charging MOS.

3. The fault detection device for charging and discharging MOS transistors according to claim 2, characterized in that, The charging MOS control module (3) also includes a second open-circuit detection circuit (32), which includes a charging MOS transistor (321). The drain of the charging MOS transistor (321) is electrically connected to the negative terminal of the diode (12), the source is electrically connected to the negative terminal of the charger, and the gate is used as the charging control terminal. The fault detection device of the charging and discharging MOS transistor is used to control the charging control terminal to input a high level after the short-circuit detection of the charging MOS is completed so as to detect the level of the voltage detection terminal to complete the open-circuit detection of the charging MOS.

4. The fault detection device for a charging / discharging MOS transistor according to claim 2 or 3, characterized in that, The first switch (211) and the second switch (311) are PNP transistors or P-MOS transistors.

5. The fault detection device for a charging / discharging MOS transistor according to claim 1, characterized in that, A voltage regulator circuit (4) is provided at the voltage detection terminal, and the voltage regulator circuit (4) is used to regulate the voltage level at the voltage detection terminal.

6. A fault detection method for a charging / discharging MOSFET, said method being implemented based on the fault detection device for a charging / discharging MOSFET as described in any one of claims 1-5, characterized in that, This includes: when a car key insertion signal or a car key removal signal is detected, controlling the car key signal detection terminal to input a low level so that the first switch (211) is turned on; detecting whether the voltage at the voltage detection terminal is low; if so, determining that the discharge MOS transistor (221) is short-circuited, and outputting the corresponding alarm signal.

7. The fault detection method for a charging / discharging MOS transistor according to claim 6, characterized in that, The system detects whether the voltage at the voltage detection terminal is low, and then proceeds as follows: if not, it controls the discharge control terminal to input a high level so that the discharge MOS transistor (221) is turned on; and detects the voltage at the voltage detection terminal. If the voltage at the voltage detection terminal is high, it is determined that the discharge MOS transistor (221) is open, and a corresponding alarm signal is output. If the voltage at the voltage detection terminal is low, then the discharge MOS transistor (221) is considered to be normal.

8. The fault detection method for a charging / discharging MOS transistor according to claim 7, characterized in that, Based on the fault detection device for charging and discharging MOSFETs as described in claim 3, the method further includes: When the discharge MOS transistor (221) is off, a low level is input to the charging signal detection terminal when a charging signal is detected, so that the second switch transistor (311) is turned on. Check if the voltage at the voltage detection terminal is low. If so, the charging MOSFET (321) is determined to be short-circuited, and the corresponding alarm signal is output.

9. The fault detection method for a charging / discharging MOS transistor according to claim 8, characterized in that, The system detects whether the voltage at the voltage detection terminal is low, and then: if not, controls the charging control terminal to input a high level so that the charging MOSFET (321) is turned on; Detect the voltage at the voltage detection terminal; If the voltage at the voltage detection terminal is high, it is determined that the charging MOS transistor (321) is open, and a corresponding alarm signal is output. If the voltage at the voltage detection terminal is low, then the charging MOS transistor (321) is considered to be normal.

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