CN210380801U

CN210380801U - Power battery high-voltage switch device based on MOSFET

Info

Publication number: CN210380801U
Application number: CN201921465759.1U
Authority: CN
Inventors: 付瑜; 阳威; 杨锡旺
Original assignee: Changzhou Soarwhale Electronic Technology Co ltd
Current assignee: Changzhou Shiwei Electronics Co ltd
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2020-04-21
Anticipated expiration: 2029-09-04

Abstract

The utility model discloses a power battery high-voltage switch device based on MOSFET, which comprises a low-voltage auxiliary power supply, an isolation power supply module, a controller unit, an isolation driving module, a load switch module and a BMS control unit; the load switch module comprises a first MOSFET transistor which is connected in a discharging loop of the power battery and is used for controlling the on-off of the discharging loop and a second MOSFET transistor which is connected in a charging loop of the power battery and is used for controlling the on-off of the charging loop; the low-voltage auxiliary power supply is respectively connected with the controller unit and the isolation power supply module; the isolation power supply module is connected with the isolation driving module; the controller unit is respectively connected with the BMS control unit and the isolation driving module; the isolation driving module is respectively connected with the first MOSFET transistor and the second MOSFET transistor. The utility model discloses can improve the corresponding speed of switch action, also eliminate the electric arc reaction that the heavy current turn-offs and cause to have good electromagnetic compatibility characteristic, still have development advantages such as miniaturization and with low costs.

Description

Power battery high-voltage switch device based on MOSFET

Technical Field

The utility model relates to a power battery high voltage switch device based on MOSFET.

Background

With the continuous development of new energy science and technology, the use of electric vehicles is more and more common. Unlike traditional automobile with fuel oil as power source, electric automobile has electric energy stored in power battery as power source. In the actual use process of the electric automobile, the electric motor is driven to operate mainly by discharging of the power battery, so that the electric automobile is driven to move. When the energy of the power battery is exhausted, an external power supply is required to be matched with the vehicle-mounted charger to charge the battery. Therefore, the charging and discharging process of the power battery is obviously the main melody in the actual operation process of the electric automobile. Usually, the charging circuit and the discharging circuit of the power battery are closed or opened mainly by means of high-voltage switching devices. Whether the high-voltage switch device can guarantee efficient and stable operation has important influence on the stability and safety of the operation of the electric automobile.

In the traditional method, a high-voltage relay is adopted to perform on-off switching of a charging and discharging loop of a power battery, and although the high-voltage relay has good voltage-resistant insulation characteristics when being disconnected, the defects of low response speed, long execution action delay time and the like and poor real-time performance still exist; meanwhile, when high voltage and large current exist in the electric loop, the high-voltage relay executes turn-off action to easily cause arc discharge reaction, so that high-energy electric arc is generated to cause overheating damage to the contact of the high-voltage relay; in addition, strong electromagnetic interference is easily generated in the switching process of the high-voltage relay, and the electromagnetic compatibility is poor; the high-voltage relay is bulky and expensive, and when applied to component devices such as a battery breaking unit and a distribution box of an electric vehicle, it is disadvantageous to improve the miniaturization and cost reduction of these electric devices.

Disclosure of Invention

The utility model aims to solve the technical problem that overcome prior art's defect, provide a power battery high voltage switchgear based on MOSFET, it can improve the corresponding speed of switching action, has also eliminated the electric arc reaction that the heavy current turn-offs caused to have good electromagnetic compatibility characteristic, still have development advantages such as miniaturization and with low costs.

In order to solve the technical problem, the technical scheme of the utility model is that: a power battery high-voltage switch device based on MOSFET comprises a low-voltage auxiliary power supply, an isolation power supply module, a controller unit, an isolation driving module, a load switch module and a BMS control unit; wherein the content of the first and second substances,

the load switch module comprises a first MOSFET transistor which is connected in a discharging loop of the power battery and is used for controlling the on-off of the discharging loop and a second MOSFET transistor which is connected in a charging loop of the power battery and is used for controlling the on-off of the charging loop;

the low-voltage auxiliary power supply is respectively connected with the controller unit and the isolation power supply module and is suitable for providing low-voltage auxiliary power supply voltage for the controller unit and the isolation power supply module;

the isolation power supply module is connected with the isolation driving module and is suitable for isolating the low-voltage auxiliary power supply voltage and converting the low-voltage auxiliary power supply voltage into a high-voltage side circuit power supply voltage so as to supply power to the isolation driving module;

the controller unit is respectively connected with the BMS control unit and the isolation driving module, is suitable for acquiring the instruction issued by the BMS control unit and outputting a signal to the isolation driving module according to the acquired instruction;

the isolation driving module is respectively connected with the first MOSFET transistor and the second MOSFET transistor and is suitable for isolating the output signal of the controller and converting the output signal into a driving signal so as to control the on-off of the first MOSFET transistor or the second MOSFET transistor.

Further, the controller unit is connected with the BMS control unit through a CAN bus.

Further provided is a concrete structure of a controller unit, which includes a linear regulator U1, a microcontroller unit, and a crystal oscillator OSC; wherein the content of the first and second substances,

the microcontroller unit comprises a microcontroller U3 and a CAN transceiver U2;

the input end of the linear voltage stabilizer U1 is connected with the output end of the low-voltage auxiliary power supply, and the output end of the linear voltage stabilizer U1 is connected with the microcontroller U3 and is suitable for converting the low-voltage auxiliary power supply voltage into a power supply voltage for the microcontroller unit to use;

the CAN transceiver U2 is connected between the microcontroller U3 and the BMS control unit and is suitable for communication between the BMS control unit and the microcontroller U3;

the crystal oscillator OSC is connected to a microcontroller U3.

Further, in order to perform under-voltage protection on the low-voltage auxiliary power supply and perform high-temperature protection on the first MOSFET transistor and the second MOSFET transistor, the controller unit further includes:

the undervoltage detection circuit is respectively connected with the low-voltage auxiliary power supply and the microcontroller U3, is suitable for detecting whether the voltage of the low-voltage auxiliary power supply output by the low-voltage auxiliary power supply sends undervoltage or not, and triggers the microcontroller U3 to control the first MOSFET transistor and the second MOSFET transistor to be switched off through the isolation driving module when the undervoltage is sent;

and/or a temperature sampling circuit, which is connected with the microcontroller U3, is suitable for collecting the temperature signals of the first MOSFET transistor and the second MOSFET transistor and transmitting the temperature signals to the microcontroller U3;

the microcontroller U3 is further adapted to perform analog-to-digital conversion on the received temperature signal to obtain a temperature value, and control the first MOSFET transistor and the second MOSFET transistor to be turned off through the isolation driving module when any temperature value is higher than a preset threshold value.

The specific structure of the undervoltage detection circuit and the temperature sampling circuit is further provided, the undervoltage detection circuit at least comprises a comparator U4 and a reference voltage Vref, a positive input end of the comparator U4 is connected to a positive output end of the low-voltage auxiliary circuit, a negative input end of the comparator U4 is connected to the reference voltage Vref, and an output end of the comparator U3526 is connected to the microcontroller U3;

the temperature sampling circuit comprises a temperature sensor NTC1 and a temperature sensor NTC2, the input ends of the temperature sensor NTC1 and the temperature sensor NTC2 are connected with the output end of the low-voltage auxiliary power supply, the output end of the low-voltage auxiliary power supply is connected with the microcontroller U3, the detection terminal of the temperature sensor NTC1 is fixed at the heat dissipation end of the first MOSFET transistor, and the detection terminal of the temperature sensor NTC2 is fixed at the heat dissipation end of the second MOSFET transistor.

Further provides a specific structure of an isolated power supply module, wherein the isolated power supply module comprises a multi-winding transformer T1, a diode D2, a diode D3, a diode D4 and an NMOS tube Q1; wherein the content of the first and second substances,

the port ① at the upper end of the primary side of the multi-winding transformer T1 is connected to the positive output end of the low-voltage auxiliary power supply, and the port ② is connected to the power ground GND;

a port ③ at the lower end of the primary side of the multi-winding transformer T1 is connected with a diode D2 in the forward direction and then is used as an isolation voltage V3 output by an isolation power supply module, and a port ④ is connected with a power ground GND;

a port ⑤ at the upper end of the secondary side of the multi-winding transformer T1 is connected with a diode D3 in the forward direction and then is used as an isolation voltage V1 output by the isolation power module, and a port ⑥ is used as an isolation ground GND1 output by the isolation power module;

a port ⑦ at the lower end of the secondary side of the multi-winding transformer T1 is connected with a diode D4 in the forward direction and then is used as an isolation voltage V2 output by the isolation power module, and a port ⑧ is used as an isolation ground GND2 output by the isolation power module;

output loads are connected in parallel between the isolation voltage V3 and the power ground GND, between the isolation voltage V1 and the isolation ground GND1 and between the isolation voltage V2 and the isolation ground GND 2;

the isolation voltage V3 is connected to the microcontroller U3, the drain of the NMOS transistor Q1 is connected to the port ② at the upper end of the primary side of the multi-winding transformer T1, the source is connected to the power ground GND, the gate is connected to the PWM output end of the microcontroller U3, the microcontroller U3 is further adapted to adjust the duty ratio of the PWM output by the isolation voltage V3 so as to adjust the isolation voltage V1 and the isolation voltage V2, and the isolation voltage V1 and the isolation voltage V2 are both connected to the isolation driving module and adapted to supply power to the isolation driving module.

Further, the isolated power supply module further comprises:

a capacitor C1 which is used as a decoupling capacitor and is connected in parallel with the output end of the low-voltage auxiliary power supply;

and/or a buffer circuit which is connected in parallel between a port ① and a port ② at the upper end of the primary side of the multi-winding transformer T1 and is used for inhibiting voltage spikes at the primary side and reducing electromagnetic interference, wherein the buffer circuit is formed by connecting a capacitor C2 and a resistor R4 in parallel and then connecting a diode D1, and the anode of the diode D1 is connected with the port ②.

The specific structure of the isolation driving module is further provided, and the isolation driving module comprises a digital isolator U5, a PMOS tube Q3, a PMOS tube Q4, an NPN type triode Q2 and an NPN type triode Q5; wherein the content of the first and second substances,

the two input ends of the digital isolator U5 are respectively connected with the microcontroller U3, one output end is connected with the base electrode of the NPN type triode Q5, and the other output end is connected with the base electrode of the NPN type triode Q2, so that the digital isolator U5 is suitable for isolating the output signal of the microcontroller U3;

the source electrode of the PMOS transistor Q3 is connected to an isolation voltage V1, and the drain electrode of the PMOS transistor Q3 is connected to the first MOSFET transistor;

the NPN type triode Q2 has a collector connected to the grid of the PMOS tube Q3, a base connected to the output end of the digital isolator U5 and an emitter connected to the isolation ground GND1, and is suitable for driving and controlling the closing or the turning-off of the PMOS tube Q3 through current amplification and signal inversion conversion of a control signal output by the digital isolator U5;

the source electrode of the PMOS transistor Q4 is connected to an isolation voltage V2, and the drain electrode of the PMOS transistor Q4 is connected to a second MOSFET transistor;

the collector of the NPN triode Q5 is connected to the gate of the PMOS transistor Q4, the base is connected to the output terminal of the digital isolator U5, and the emitter is connected to the isolation ground GND2, so that the NPN triode Q5 is adapted to drive and control the PMOS transistor Q4 to be turned on or off through current amplification and signal inversion conversion of the control signal output by the digital isolator U5.

Further, the first MOSFET transistor is an NMOS transistor Q6, a gate of the NMOS transistor Q6 is connected to a drain of the PMOS transistor Q3, the drain is connected to the positive electrode of the power battery, and a source is respectively connected to the positive end of the motor in the discharge circuit and the isolation ground GND 1;

the second MOSFET transistor is an NMOS transistor Q7, a gate of the NMOS transistor Q7 is connected to a drain of the PMOS transistor Q4, a drain of the NMOS transistor Q7 is connected to a positive terminal of a charger in the charging loop, and a source of the NMOS transistor Q7 is connected to a positive terminal of the power battery and an isolated ground GND2, respectively.

Further, the load switch module further comprises a resistor R16, a resistor R17, a resistor R18 and a resistor R19; wherein the content of the first and second substances,

the drain electrode of the PMOS tube Q3 is connected with the gate electrode of the NMOS tube Q6 through a resistor R16;

the drain electrode of the PMOS tube Q4 is connected with the gate electrode of the NMOS tube Q7 through a resistor R18;

the resistor R17 is connected in parallel between the grid and the source of the NMOS transistor Q6 to be used as a bleeder resistor;

the resistor R19 is connected in parallel between the gate and the source of the NMOS transistor Q7 to serve as a bleeder resistor.

After the technical scheme is adopted, the low-voltage auxiliary power supply respectively provides low-voltage auxiliary power supply voltage for the controller unit and the isolation power supply module; the isolation power supply module isolates the low-voltage auxiliary power supply voltage and converts the low-voltage auxiliary power supply voltage into a high-voltage side circuit power supply voltage so as to supply power to the isolation driving module; the controller unit acquires the instruction issued by the BMS control unit and outputs a signal to the isolation driving module according to the acquired instruction; keep apart drive module and keep apart controller output signal and convert drive signal in order to control first MOSFET transistor or second MOSFET transistor break-make, the utility model discloses mainly be applied to electric automobile's power battery unit and block terminal that opens circuit compares in the mode of current adoption high-voltage relay as the high-tension switch part, the utility model has the advantages of it is following:

(1) the utility model can quickly respond to the control signal and accelerate the executing speed of the switch action;

(2) the utility model can solve the problem of electric arc generation in the process of electrified turn-off of the high-voltage relay;

(3) the utility model can realize the digital control of the BMS control unit to the switch element, and improve the working reliability of the whole switch device;

(4) the utility model can monitor the power supply voltage output by the low-voltage auxiliary power supply in real time, has the function of power supply under-voltage protection, and avoids the misoperation of the traditional method when the power supply is under-voltage;

(5) the utility model can monitor the temperature rise change of the first MOSFET transistor and the second MOSFET transistor in real time, has the over-temperature protection function, and avoids the overheating damage in the switching-on process of the switch element;

(6) the utility model has the characteristics of small and with low costs, can adapt to the miniaturization of power battery energy storage system spare part and the development trend of low cost.

Drawings

Fig. 1 is a schematic block diagram of a MOSFET-based power battery high voltage switching device of the present invention;

fig. 2 is a circuit diagram of the power battery high-voltage switch device based on the MOSFET of the present invention.

Detailed Description

In order that the present invention may be more readily and clearly understood, the following detailed description of the present invention is provided in connection with the accompanying drawings.

As shown in fig. 1 and 2, a high-voltage switch device of a power battery based on a MOSFET includes a low-voltage auxiliary power supply, an isolated power supply module, a controller unit, an isolated driving module, a load switch module and a BMS control unit; wherein the content of the first and second substances,

In this embodiment, the controller unit is connected to the BMS control unit through a CAN bus.

As shown in fig. 2, the controller unit mainly comprises a linear voltage stabilizing circuit, a microcontroller unit, a power supply monitoring circuit and a temperature sampling circuit. The linear voltage stabilizing circuit comprises a linear voltage stabilizer U1, the input of which is connected with the output end of the low-voltage auxiliary power supply, the output of which is connected with the power supply ends of the microcontroller unit and the temperature sampling circuit, and the linear voltage stabilizing circuit mainly converts the voltage of the low-voltage auxiliary power supply into the power supply voltage which can be used by the microcontroller unit and the temperature sampling circuit. The microcontroller unit comprises a microcontroller U3, a crystal oscillator OSC and a CAN transceiver U2, the crystal oscillator OSC is connected with a clock input pin XTAL and an EXTAL of the microcontroller U3, the CAN transceiver U2 is connected with a communication peripheral pin TXD and an RXD of the microcontroller U3, the microcontroller unit controls the switching states of the first MOSFET transistor and the second MOSFET transistor according to a switching instruction obtained by CAN communication and also bears the control task of the isolation power supply module, meanwhile, the temperature rise change of the first MOSFET transistor and the second MOSFET transistor is obtained through analog-to-digital conversion, whether the power supply voltage is under-voltage or not is judged through external interruption, the power supply under-voltage and MOSFET over-temperature conditions are timely protected, and the fault condition is reported to the BMS control unit through CAN communication. The power supply monitoring circuit comprises a comparator U4, a reference voltage Vref, a resistor R1 and a resistor R2, wherein the positive input end of the comparator U4 is connected with the positive output end of the low-voltage auxiliary power supply through a resistor R1, the negative input end of the comparator U4 is connected with the reference voltage Vref, the positive input end of the comparator U592 is also connected with a power ground GND through a resistor R2, and the output end of the comparator U595 is connected with an external interrupt input pin INT of the microcontroller U3. The temperature sampling circuit comprises a resistor R6, a resistor R7, a temperature sensor NTC1 and a temperature sensor NTC2, the inputs of the temperature sampling circuit are connected to the output end of the low-voltage auxiliary power supply, and the outputs of the temperature sampling circuit are connected to the analog-to-digital converter ports AD1 and AD2 of the microcontroller U3; the detection terminal of the temperature sensor NTC1 is fixed at the heat dissipation end of the first MOSFET transistor, the detection terminal of the temperature sensor NTC2 is fixed at the heat dissipation end of the second MOSFET transistor, and the temperature sampling circuit mainly utilizes the temperature sensor to convert the temperature rise variation of the switching element into a voltage signal and transmits the voltage signal to the microcontroller for analog-to-digital conversion.

The isolation power supply module is mainly composed of a multi-winding transformer T1, a diode D1, a diode D2, a diode D3, a diode D4, an NMOS tube Q1, a resistor R3, a resistor R4, a resistor R5, a resistor R8, a resistor R9, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6 and a capacitor C7, as shown in FIG. 2, the isolation power supply module is mainly composed of a multi-winding transformer T1, a diode D4672, a diode D1, a resistor V1, a diode D1, a diode C1, a capacitor C1, a negative output terminal of a low-voltage auxiliary power supply output terminal connected in parallel to the low-voltage auxiliary power supply, a positive output terminal of the low-voltage auxiliary power supply is connected to the power supply voltage Vin of the whole switching device, a negative output terminal of the switching device is connected to the power supply voltage of the main power supply, a power supply terminal of the power supply, a power supply voltage is connected to the power supply, a power supply voltage, a power supply voltage is connected to the power supply, a power supply voltage, a power supply voltage, a power supply voltage, a power supply voltage, a power supply.

As shown in fig. 2, the isolation driving module mainly includes a digital isolator U5, a capacitor C6, a capacitor C7, a diode D5, a diode D6, a PMOS transistor Q3, a PMOS transistor Q4, an NPN transistor Q2, an NPN transistor Q5, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, and the like. One input end of the digital isolator U5 is connected to the control port IO1 of the microcontroller U3, the other input end is connected to the control port IO2 of the microcontroller U3, one output end is connected to one end of the resistor R10, the other output end is connected to one end of the resistor R14, and the digital isolator U5 is used for isolating signals output by the microcontroller U3. The capacitor C6 is connected between the source of the PMOS transistor Q3 and the isolation ground GND1 as an energy storage capacitor and is used for buffering the first MOSFET transistor driven by the isolation power supply V1. The resistor R12 and the diode D5 are connected in parallel between the source and the gate of the PMOS transistor Q3 and used for keeping the driving voltage between the gate and the source of the PMOS transistor Q3 stable and preventing the breakdown failure of the PMOS transistor Q3 caused by overhigh voltage of a driving signal; the NPN type triode Q2 is used for driving and controlling the closing or the switching off of a PMOS tube Q3 by carrying out current amplification and signal inversion conversion on a control signal output by the digital isolator U5, the collector of the NPN type triode is connected with the grid electrode of a PMOS tube Q3, the base of the NPN type triode is connected with the other end of the resistor R10, and the emitter of the NPN type triode is connected with an isolation ground GND 1; the resistor R11 is connected between the base and the emitter of the NPN transistor Q2, and is used to ensure that the NPN transistor Q2 is in an open circuit state when the entire circuit is in an initial state. The resistor R13 and the diode D6 are connected in parallel between the source and the gate of the PMOS transistor Q4 and used for keeping the driving voltage between the gate and the source of the PMOS transistor Q4 stable and preventing the breakdown failure of the PMOS transistor Q4 caused by overhigh voltage of a driving signal; the NPN type triode Q5 is used for driving and controlling the closing or the switching of the PMOS transistor Q4 by current amplification and signal inversion of the control signal output by the digital isolator U5, and has a collector connected to the gate of the PMOS transistor Q4, a base connected to the other end of the resistor R14, and an emitter connected to the isolation ground GND 2; the resistor R15 is connected between the base and emitter of the NPN transistor Q5, and is used to ensure that the NPN transistor Q5 is in an open circuit state when the entire circuit is in an initial state.

As shown in fig. 2, the first MOSFET transistor is an NMOS transistor Q6, the second MOSFET transistor is an NMOS transistor Q7, and the load switch module mainly includes devices such as an NMOS transistor Q6, an NMOS transistor Q7, a resistor R16, a resistor R17, a resistor R18, and a resistor R19. The resistor R16 is connected between the drain of the PMOS transistor Q3 and the gate of the NMOS transistor Q6 and is used for limiting the drive current of the MOS transistor and preventing the drive current from being overlarge to damage the NMOS transistor Q6; the resistor R17 is connected in parallel between the grid and the source of the NMOS transistor Q6 and is used as a current-discharging resistor, so that the power-off process of the NMOS transistor Q6 is accelerated, and the failure of the NMOS transistor Q6 due to overvoltage breakdown caused by static charge accumulation can be prevented; the drain of the NMOS tube Q6 is connected to the positive pole of the power battery, and the source of the NMOS tube Q6 is connected to the positive end of the motor of the discharge loop and to the isolation ground GND 1. The resistor R18 is connected between the drain of the PMOS transistor Q4 and the grid of the NMOS transistor Q7 and is used for limiting the driving current of the NMOS transistor Q7 and preventing the driving current from being too large and damaging the NMOS transistor Q7; the resistor R19 is connected in parallel between the grid and the source of the NMOS transistor Q7 and is used as a current-discharging resistor, so that the power-off process of the NMOS transistor Q7 is accelerated, and the failure of the NMOS transistor Q7 due to overvoltage breakdown caused by static charge accumulation can be prevented; the drain of the NMOS transistor Q7 is connected to the positive terminal of the charger of the charging loop, and the source thereof is connected to the positive terminal of the power battery and to the isolation ground GND 2.

The utility model relates to a hardware circuit working process specifically says to be:

in the initial stage, the low-voltage auxiliary power supply outputs a power supply voltage Vin, and the linear voltage regulator U1 outputs a low-voltage control circuit power supply voltage VDD; the microcontroller U3 is powered on to start an initialization process, the crystal oscillator OSC provides a stable clock signal, the PWM peripheral outputs a low level, and the CAN communication interface finishes initialization readiness; the digital control ports IO1 and IO2 output low level, the NPN type triode Q2 is in a turn-off state without base current, the grid and the source of the NMOS tube Q1 are both in a high level state, the grid-source voltage difference is very small, so that the NMOS tube Q1 is also in a turn-off state, the isolation power supply module is in a shutdown state without voltage input, and the NMOS tube Q6 and the NMOS tube Q7 are in a turn-off state without driving signals; the analog-to-digital converter port AD0 obtains a zero level signal, the analog-to-digital converter port AD1 obtains a temperature value of a heat dissipation end of a second MOSFET transistor, the analog-to-digital converter port AD2 obtains a temperature value of a heat dissipation end of a first MOSFET transistor, and whether the obtained temperature value belongs to a normal value range is judged; when the comparator U4 detects that the low-voltage auxiliary power supply voltage Vin belongs to a normal value range, the output signal INT is in a high level state; if the output signal INT of the undervoltage detection circuit is in a high level state and the temperature values of the heat dissipation ends of the NMOS tube Q6 and the NMOS tube Q7 belong to a normal value range, the microcontroller U3 starts the conversion process of the isolation power supply module; if any detection signal does not meet the threshold requirement, the microcontroller U3 continues to wait;

when the PWM signal is at a low level, the NMOS tube Q is turned off, and coils between a port and a port at the upper end of the primary side of the multi-winding transformer T start follow current discharge through a diode D and a resistor R, meanwhile, coils between a port 0 and a port at the lower end of the primary side of the multi-winding transformer T, coils between a port and a port at the upper end of the secondary side and coils between a port and a port at the lower end of the secondary side form an isolation voltage V, an isolation voltage V and an isolation voltage V respectively, and discharge through resistors R, R and R respectively, and then charge capacitors C, C and C respectively, and the microcontroller U obtains the magnitude of the isolation voltage V output by the port at the lower end of the primary side through analog-to-digital conversion and then adjusts the magnitude of the PWM output signal, and judges whether the duty ratio of the primary side voltage and the secondary side voltage of the microcontroller V tend to a preset value and the isolation voltage of the isolation tube V when the isolation voltage V ratio of the isolation voltage tends to a preset value, the microcontroller U tends to control the isolation voltage and the isolation voltage of the isolation tube V to be stable, and the isolation voltage of the isolation tube V is obtained if the isolation voltage of the isolation tube V is reached by the turn-off conversion, and the microcontroller U, and the isolation voltage of the isolation tube is also tends to obtain the isolation voltage of the isolation tube;

in the power-on stage of the driving signal, when the work of the isolation power supply module tends to be stable, the isolation voltage V1, the isolation voltage V2 and the isolation voltage V3 all reach preset values; the microcontroller U3 acquires a load switch closing instruction issued by the BMS control unit through CAN communication, and supposing that the instruction requires to close the NMOS tube Q6, at the moment, the microcontroller U3 controls the port IO1 to output high level, the high level signal is still obtained after the isolation processing of the digital isolator U5, the NPN type triode Q2 obtains base current and is in an on state, the source of the PMOS tube Q3 still keeps high level, the grid is in a low level state due to negative charge injection, at the moment, the PMOS tube Q3 is in an on state due to the rising of grid source voltage, and therefore the charges accumulated on the energy storage capacitor C6 are rapidly guided to drive the NMOS tube Q6; assuming that an instruction obtained by CAN communication requires to close the NMOS tube Q7, at the moment, the microcontroller U3 controls the port IO2 to output a high level, the high level signal is still obtained after the isolation processing of the digital isolator U5, the NPN type triode Q5 obtains a base current and is in an on state, the source of the PMOS tube Q4 still keeps the high level, the grid is in a low level state due to negative charge injection, at the moment, the PMOS tube Q4 is in an on state due to the rise of grid source voltage, and therefore the charges accumulated on the energy storage capacitor C7 are rapidly guided to drive the NMOS tube Q7;

in the power-off stage of the driving signal, the microcontroller U3 acquires a load switch turn-off instruction issued by the BMS control unit through CAN communication, and if the instruction requires to turn off the NMOS transistor Q6, at this time, the microcontroller U3 controls the output of the port IO1 to be at a low level, the low level signal is still obtained after the isolation processing of the digital isolator U5, the NPN type triode Q2 is in a turn-off state due to loss of base current, the source of the PMOS transistor Q3 is still at a high level, the gate is in a high level state due to negative charge pumping, and at this time, the PMOS transistor Q3 is in a turn-off state due to reduction of gate source voltage; finally, the driving signal of the NMOS transistor Q6 disappears, and the gate-source voltage thereof is discharged through the resistor R17 and reduced to zero, so that the NMOS transistor Q6 is turned off; assuming that an instruction obtained by CAN communication requires to turn off the NMOS tube Q7, at the moment, the microcontroller U3 controls the port IO2 to output a low level, the low level signal is still obtained after the isolation processing of the digital isolator U5, the NPN type triode Q5 loses base current and is in a turn-off state, the source of the PMOS tube Q4 still keeps a high level, the grid is in a high level state due to the pumping of negative charges, and at the moment, the PMOS tube Q4 is in a turn-off state due to the reduction of grid source voltage; finally, the driving signal of the NMOS transistor Q7 disappears, and the gate-source voltage thereof is discharged through the resistor R19 and reduced to zero, so that the NMOS transistor Q7 is turned off;

in the stage of power supply undervoltage protection, when the voltage division value of the power supply voltage Vin output by the low-voltage auxiliary power supply is lower than the reference voltage Vref through the resistor R1 and the resistor R2, the output signal INT of the comparator U4 is in a low-level state, and the falling edge of the signal INT changing from a high level to a low level triggers the microcontroller U3 to enter a corresponding interrupt service program; in the interrupt processing process, the microcontroller U3 firstly sends a power supply undervoltage early warning event to the BMS control unit through CAN communication, and then waits for the BMS control unit to send a corresponding instruction for processing the undervoltage event; if the command sent by the BMS control unit is not received within the specified time, the microcontroller U3 starts automatic processing, firstly, the drive signals of the NMOS tube Q6 and the NMOS tube Q7 are powered off, then the PWM output is stopped to power off the isolation power supply module, the CAN communication interface is closed, the microcontroller U3 enables the external interruption INT rising edge to wake up the interruption, and finally the microcontroller U3 enters a sleep state. When the divided voltage value of the power supply voltage Vin output by the low-voltage auxiliary power supply is higher than the reference voltage Vref through the resistor R1 and the resistor R2, the output signal INT of the comparator U4 is in a high level state, the rising edge of the signal INT changing from the low level to the high level wakes up the microcontroller U3, then the microcontroller U3 starts to execute the power-on work of the isolation power supply module, and removes the power supply undervoltage protection state to enter a normal work mode.

In the over-temperature protection stage, the microcontroller U3 indirectly obtains current temperature values of the heat dissipation ends of the NMOS transistor Q6 and the NMOS transistor Q7 by obtaining voltage signals of the analog-to-digital converter ports AD1 and AD2, and when any one of the temperature values is higher than a preset threshold value, the microcontroller U3 starts to enter a software interrupt program; in the interrupt processing process, the microcontroller U3 firstly sends a load switch over-temperature early warning event to the BMS control unit through CAN communication, and then waits for the BMS control unit to send a corresponding instruction for processing the over-temperature early warning event; if the command sent by the BMS control unit is not received within the specified time, the microcontroller U3 starts automatic processing, firstly, the power-off task of the drive signals of the NMOS tube Q6 and the NMOS tube Q7 is executed, then, the PWM output is stopped to power off the isolation power supply module, the temperature change conditions of the radiating fins of the NMOS tube Q6 and the NMOS tube Q7 are continuously monitored, and the temperature change conditions are reported to the BMS control unit by the microcontroller U3 through CAN communication at regular intervals; when the temperature values of the heat dissipation ends of the NMOS tube Q6 and the NMOS tube Q7 are lower than a preset threshold value, the microcontroller U3 starts to execute the power-on work of the isolation power supply module, removes the over-temperature protection state and enters a normal working mode.

The above-mentioned embodiments further explain in detail the technical problems, technical solutions and advantages solved by the present invention, and it should be understood that the above only is a specific embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

In the description of the present invention, it is to be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplification of description, and do not indicate or imply that the equipment or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the present disclosure, unless otherwise expressly stated or limited, the first feature may comprise both the first and second features directly contacting each other, and also may comprise the first and second features not being directly contacting each other but being in contact with each other by means of further features between them. Also, the first feature being above, on or above the second feature includes the first feature being directly above and obliquely above the second feature, or merely means that the first feature is at a higher level than the second feature. A first feature that underlies, and underlies a second feature includes a first feature that is directly under and obliquely under a second feature, or simply means that the first feature is at a lesser level than the second feature.

Claims

1. A power battery high-voltage switch device based on MOSFET is characterized by comprising a low-voltage auxiliary power supply, an isolation power supply module, a controller unit, an isolation driving module, a load switch module and a BMS control unit; wherein the content of the first and second substances,

2. The MOSFET-based power cell high voltage switching device according to claim 1, wherein the controller unit is connected to the BMS control unit through a CAN bus.

3. The MOSFET-based power cell high voltage switching arrangement according to claim 2, wherein the controller unit comprises a linear regulator U1, a microcontroller unit and a crystal oscillator OSC; wherein the content of the first and second substances,

the crystal oscillator OSC is connected to a microcontroller U3.

4. The MOSFET-based power cell high voltage switching device of claim 3, wherein the controller unit further comprises:

5. The MOSFET-based power battery high-voltage switching device as claimed in claim 4, wherein the under-voltage detection circuit comprises at least a comparator U4 and a reference voltage Vref, the comparator U4 has a positive input connected to the positive output of the low-voltage auxiliary circuit, a negative input connected to the reference voltage Vref, and an output connected to the microcontroller U3;

6. The MOSFET-based power cell high voltage switching device of claim 3,

the isolation power supply module comprises a multi-winding transformer T1, a diode D2, a diode D3, a diode D4 and an NMOS tube Q1; wherein the content of the first and second substances,

7. The MOSFET-based power cell high voltage switching device of claim 6, wherein the isolated power module further comprises:

8. The MOSFET-based power battery high-voltage switching device of claim 6, wherein the isolation driving module comprises a digital isolator U5, a PMOS transistor Q3, a PMOS transistor Q4, an NPN transistor Q2 and an NPN transistor Q5; wherein the content of the first and second substances,

9. The MOSFET-based power cell high voltage switching device of claim 8,

the first MOSFET transistor is an NMOS transistor Q6, the grid electrode of the NMOS transistor Q6 is connected to the drain electrode of the PMOS transistor Q3, the drain electrode is connected to the positive electrode of the power battery, and the source electrode is respectively connected to the positive end of the motor in the discharge loop and the isolation ground GND 1;

10. The MOSFET-based power cell high voltage switching device of claim 9, wherein the load switch module further comprises a resistor R16, a resistor R17, a resistor R18, and a resistor R19; wherein the content of the first and second substances,