Protection circuit and device of electric vehicle controller

Abstract

The invention provides a protection circuit and device of an electric vehicle controller, and relates to the field of electric vehicle accessories. The circuit comprises a rectification unit, a first step-down unit, a second step-down unit, an MCU controller unit, a PWM-to-DAC unit and an electronic load unit which are sequentially connected in series, and also comprises a turning handle signal detection unit and a battery voltage detection unit which are respectively connected with the MCU controller unit, the output end of the rectification unit is connected with the electronic load unit. The output end of the first voltage reduction unit is connected with the electronic load unit. Wherein the input end of the rectifying unit is used for being connected with a three-phase line of a motor of the electric vehicle, the input end of the rotating handle signal detection unit is used for being connected with a rotating handle signal line of the electric vehicle, and the battery voltage detection unit is used for being connected with the output end of a power supply battery of the electric vehicle. The circuit can solve the problem of dredging the reverse charging current of the motor after the battery protection board is turned off, prevents the MOS tube of the controller from overvoltage breakdown, and protects the core device of the controller.

Description

Technical Field

[0001] This application relates to the field of electric vehicle accessories. Specifically, it relates to a protection circuit and device for an electric vehicle controller. Background Art

[0002] With the popularization of electric vehicles, the safety and reliability of vehicles under complex working conditions have become key technical challenges. Especially in the long downhill scenario, if the energy generated by the motor during reverse charging cannot be effectively diverted, it is extremely easy to cause overvoltage breakdown of the core components of the controller (such as MOS transistors), leading to system failures and even safety hazards.

[0003] In the process of implementing this application, the inventor found that in the long downhill scenario, the controller is extremely easy to be burned out because the current industry generally relies on the hardware protection mechanism of the battery protection board to deal with the reverse charging problem. Specifically, when the reverse charging of the motor causes the battery voltage to exceed the threshold, the shutdown protection mechanism of the protection board will be triggered. However, during this period, the reverse charging current continuously generated by the motor loses an effective diversion path and cannot be released through the battery circuit, but instead directly impacts the controller MOS transistor, causing a risk of instantaneous overvoltage breakdown.

[0004] Therefore, there is an urgent need for a circuit that can effectively protect the electric vehicle controller when the shutdown protection mechanism is triggered to address this problem. Summary of the Invention

[0005] To solve the above problems, this application provides a protection circuit and device for an electric vehicle controller, which can solve the problem of diverting the reverse charging current of the motor after the battery protection board shuts down, avoid overvoltage breakdown of the controller MOS transistor, protect the core components of the controller, and improve the service life of the controller and the driving safety of the vehicle.

[0006] This application is implemented as follows:

[0007] In a first aspect, this application provides a protection circuit for an electric vehicle controller, which includes a rectification unit, a first buck unit, a second buck unit, an MCU controller unit, a PWM to DAC unit, and an electronic load unit connected in series in sequence, and also includes a throttle signal detection unit and a battery voltage detection unit respectively connected to the MCU controller unit; the output end of the rectification unit is connected to the electronic load unit, and the output end of the first buck unit is connected to the electronic load unit. Among them, the input end of the rectification unit is used to be connected to the three-phase lines of the electric vehicle motor, the input end of the throttle signal detection unit is used to be connected to the throttle signal line of the electric vehicle, and the battery voltage detection unit is used to be connected to the output end of the power supply battery of the electric vehicle.

[0008] Among them, the throttle signal detection unit is used to collect the analog voltage information output by the vehicle throttle, convert the analog voltage signal into a digital signal and then transmit it to the MCU controller unit; the battery voltage detection unit is used to collect the power supply voltage signal of the electric vehicle battery and transmit the power supply voltage signal to the MCU control unit; the PWM to DAC unit is used to convert the pulse width modulation signal output by the MCU controller unit into an analog control signal to drive the operation of the electronic load unit; the MCU controller unit is used to judge the driving state of the electric vehicle according to the digital signal received from the throttle signal detection unit and the power supply voltage signal received from the battery voltage detection unit, and output a corresponding pulse width modulation signal according to the driving state of the electric vehicle.

[0009] Exemplarily, the brake handle detection unit can be further used to collect the first voltage analog signal output by the electric vehicle brake handle, convert the first voltage analog signal into a corresponding digital signal and then transmit it to the MCU controller unit. Thus, the MCU controller unit can further accurately judge the driving state of the electric vehicle according to the digital signal transmitted from the throttle signal detection unit, the power supply voltage signal transmitted from the battery voltage detection unit and the digital signal transmitted from the brake handle detection unit.

[0010] In some implementation manners, the rectification unit includes diode D3, diode D4, diode D5, diode D6, diode D7, diode D8 and capacitor C5. Among them, the anodes of diode D3, diode D4 and diode D5 are all connected to the first end of capacitor C5, the cathodes of diode D6, diode D7 and diode D8 are all connected to the second end of capacitor C5, the anode of diode D8 is connected to the cathode of diode D3, the anode of diode D7 is connected to the cathode of diode D4, the anode of diode D6 is connected to the cathode of diode D5, the anode of diode D8 is used to be connected to the U-phase wire of the electric vehicle motor, the anode of diode D7 is used to be connected to the V-phase wire of the electric vehicle motor, and the anode of diode D6 is used to be connected to the W-phase wire of the electric vehicle motor.

[0011] In some implementations, the first buck unit includes: a DC-DC buck chip U2, a diode D9, a resistor R25, a resistor R24, a resistor R23, an inductor L3, an inductor L4, a capacitor C6, a capacitor C7, and a capacitor C9. Among them, the VIN pin of the DC-DC buck chip U2 is connected to the cathode of the diode D6 through the inductor L3, the VIN pin of the DC-DC buck chip U2 is connected to the GND pin of the DC-DC buck chip U2 through the capacitor C6, the GND pin of the DC-DC buck chip U2 is connected to the FB pin of the DC-DC buck chip U2 through the resistor R25, the FB pin of the DC-DC buck chip U2 is connected to the VS pin of the DC-DC buck chip U2 after passing through the resistor R24 and the inductor L4, the IS pin of the DC-DC buck chip U2 is connected to the VS pin of the DC-DC buck chip U2 through the resistor R23, the VB pin of the DC-DC buck chip U2 is connected to the VC pin of the DC-DC buck chip U2 through the capacitor C7, the cathode of the diode D9 is connected to the VS pin of the DC-DC buck chip U2, and the cathode of the diode D9 is connected to the VS pin of the DC-DC buck chip U2 after passing through the capacitor C9 and the inductor L4.

[0012] In some implementations, the second buck unit includes: a linear voltage regulator chip U5, an inductor L5, a capacitor C8, a capacitor C10, and a capacitor C11. Among them, the VIN pin of the linear voltage regulator chip U5 is connected to the VS pin of the DC-DC buck chip U2 through the inductor L4, the capacitors C8, C10, and C9 are connected in parallel in pairs, the VIN pin of the linear voltage regulator chip U5 is connected to the GND pin of the linear voltage regulator chip U5 after passing through the capacitor C10 and the inductor L5, and the VOUT pin of the linear voltage regulator chip U5 is connected to the GND pin of the linear voltage regulator chip U5 through the capacitor C11.

[0013] In some implementations, the MCU controller unit includes: a processor chip U4 of the CW32F003E4P7 model, a capacitor C12, a resistor R26, a light-emitting diode LED1, and a terminal block H2. Among them, the VSS pin of the processor chip U4 is connected to the VDD pin of the processor chip U4 through the capacitor C12, the VDD pin of the processor chip U4 is connected to the VOUT pin of the linear voltage regulator chip U5, the terminal 1 of the terminal block H2 is connected to the VDD pin of the processor chip U4, the terminal 2 of the terminal block H2 is connected to the PA02 pin of the processor chip U4, the terminal 3 of the terminal block H2 is connected to the PA05 pin of the processor chip U4, the VDD pin of the processor chip U4 is connected to the anode of the light-emitting diode LED1 through the resistor R26, and the cathode of the light-emitting diode LED1 is connected to the PB05 pin of the processor chip U4.

[0014] In some implementations, the PWM-to-DAC unit includes: capacitor C13, capacitor C14, capacitor C15, resistor R27, and resistor R28. Among them, one end of capacitor C13 is connected to pin PB02 of processor chip U4, and the other end is grounded after passing through resistor R27, resistor R28, and capacitor C15. The common terminal of resistor R27 and resistor R28 is grounded through capacitor C14.

[0015] In some implementations, the electronic load unit includes: comparator U1.1, comparator U3.2, triode Q2, triode Q3, triode Q4, triode Q5, MOS transistor Q1, MOS transistor Q6, inductor L1, inductor L2, resistor R1, resistor R9, resistor R7, resistor R8, resistor R5, resistor R6, resistor R4, resistor R3, resistor R2, resistor R22, resistor R21, resistor R20, resistor R18, resistor R19, resistor R16, resistor R17, resistor R14, resistor R15, capacitor C10, capacitor C18, and capacitor C4. Among them, the non-inverting input terminal of comparator U1.1 is connected to the common terminal of resistor R28 and capacitor C15. The non-inverting input terminal of comparator U1.1 is connected to the output terminal of comparator U1.1 through the parallel connection of capacitor C18 and resistor R1. The power input terminal of comparator U1.1 is connected to the pin VS of DC-DC buck chip U2 through inductor L4. The power input terminal of comparator U1.1 is grounded through capacitor C10. The inverting input terminal of comparator U1.1 is grounded through resistor R9 and resistor R2. The output terminal of comparator U1.1 is connected to the base of triode Q2. The base of triode Q2 is connected to the emitter of triode Q2 through resistor R8. The base of triode Q2 is connected to pin PB03 of processor chip U4 through resistor R7. The collector of triode Q2 is connected to the base of triode Q3 through resistor R4. The base of triode Q3 is connected to the emitter of triode Q3 through resistor R6. The emitter of triode Q3 is connected to the pin VS of DC-DC buck chip U2 through inductor L4. The collector of triode Q3 is connected to the gate of MOS transistor Q1 through resistor R4. The gate of MOS transistor Q1 is connected to the source of MOS transistor Q1 through resistor R3. The drain of MOS transistor Q1 is connected to the cathode of diode D6. The drain of MOS transistor Q1 is grounded through resistor R2 and inductor L1.The non-inverting input terminal of comparator U3.2 is connected to the common terminal of resistor R28 and capacitor C15. The non-inverting input terminal of comparator U3.2 is connected to the output terminal of comparator U3.2 through the parallel-connected capacitor C15 and resistor R4. The inverting input terminal of comparator U3.2 is grounded through resistor R14 and resistor R22. The output terminal of comparator U3.2 is connected to the base of transistor Q5. The base of transistor Q5 is connected to the emitter of transistor Q5 through resistor R16. The base of transistor Q5 is connected to pin PB03 of processor chip U4 through resistor R17. The collector of transistor Q5 is connected to the base of transistor Q4 through resistor R19. The base of transistor Q4 is connected to the emitter of transistor Q4 through resistor R18. The emitter of transistor Q4 is connected to pin VS of DC-DC buck chip U2 through inductor L4. The collector of transistor Q4 is connected to the gate of MOS transistor Q6 through resistor R20. The gate of MOS transistor Q6 is connected to the source of MOS transistor Q6 through resistor R21. The drain of MOS transistor Q6 is connected to the cathode of diode D6. The drain of MOS transistor Q6 is grounded through resistor R22 and inductor L2.

[0016] In some implementation manners, the throttle signal detection unit includes: terminal block J4, diode D10, capacitor C17, capacitor C16, resistor R29, resistor R30, and resistor R31. Among them, terminal block J4 is used to be connected to the throttle signal wire of the electric vehicle. Terminal 2 of terminal block J4 is connected to terminal 3 of terminal block J4 through resistor R30. Terminal 2 of terminal block J4 is connected to terminal 3 of terminal block J4 through resistor R29 and capacitor C17. The common terminal of resistor R29 and capacitor C17 is connected to pin PA06 of processor chip U4. Terminal 1 of terminal block J4 is grounded through capacitor C16. Terminal 1 of terminal block J4 is connected to pin VOUT of linear voltage regulator chip U5 through resistor R31. The anode of diode D10 is connected to pin VOUT of linear voltage regulator chip U5. The cathode of diode D10 is connected to terminal 1 of terminal block J4.

[0017] In some implementation manners, the battery voltage detection unit includes: capacitor C2, resistor R32, resistor R33, resistor R34, and resistor R35. Among them, one end of resistor R35 is grounded and is used to be connected to the negative electrode of the power supply battery of the electric vehicle, and the other end is sequentially connected to the positive electrode of the power supply battery of the electric vehicle through resistor R34, resistor R33, and resistor R32. Capacitor C2 is in parallel with resistor R35. The common terminal of resistor R35 and resistor R34 is connected to pin PA04 of processor chip U4.

[0018] In a second aspect, the present application provides a protection device for an electric vehicle controller, which includes any one of the protection circuits of the electric vehicle controller in the first aspect.

[0019] Compared with the prior art, the present application has at least the following advantages or beneficial effects:

[0020] The present application provides a protection circuit for an electric vehicle controller. After rectifying the alternating current reversely charged from the three-phase motor wires into direct current through a rectification unit, it is directly connected to an electronic load unit to form a discharge channel independent of the battery circuit. Moreover, the rectified high-voltage direct current is step-down by a first step-down unit (exemplarily a BUCK structure) and a second step-down unit (exemplarily an LDO structure) to provide a stable power supply for the MCU controller and the electronic load, ensuring continuous operation even when the lithium battery protection board is turned off. That is, the reverse charging current forms a closed loop from the three-phase motor wires → rectification unit → electronic load unit → ground wire, avoiding energy accumulation at both ends of the MOS tube, and using the reverse charging energy to supply power to its own circuit (without relying on the battery), ensuring that the system can still operate during the off period of the protection board, realizing "continuous protection even when power is off".

[0021] At the same time, through the dual-parameter acquisition of the throttle signal detection unit and the battery voltage detection unit, misoperation during normal deceleration or short-term downhill can be reduced.

[0022] In addition, the digital PWM signal output by the MCU is converted into an analog voltage signal through the PWM to DAC unit to linearly control the on-resistance of the electronic load. Thus, because the MCU monitors the current and voltage of the discharge loop in real time and dynamically adjusts the PWM duty cycle, it can be ensured that the discharge power matches the reverse charging energy.

[0023] Furthermore, the throttle signal detection unit is connected in parallel with the original vehicle throttle wire, and the battery voltage detection unit is connected in parallel with the original vehicle battery terminal, without interfering with the original vehicle signal transmission. Compared with the traditional scheme of modifying the original vehicle circuit (such as adding a relay or cutting off the original line), the maintenance cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic structural diagram of an embodiment of a protection circuit for an electric vehicle controller of the present application;

[0026] Figure 2 It is a circuit schematic diagram of the rectification unit in an embodiment of a protection circuit for an electric vehicle controller of the present application;

[0027] Figure 3Schematic diagram of the first buck unit and the second buck unit in an embodiment of the protection circuit of an electric vehicle controller of the present application;

[0028] Figure 4 Schematic diagram of the MCU controller unit in an embodiment of the protection circuit of an electric vehicle controller of the present application;

[0029] Figure 5 Schematic diagram of the PWM to DAC unit in an embodiment of the protection circuit of an electric vehicle controller of the present application;

[0030] Figure 6 Schematic diagram of the electronic load unit in an embodiment of the protection circuit of an electric vehicle controller of the present application;

[0031] Figure 7 Schematic diagram of the throttle signal detection unit in an embodiment of the protection circuit of an electric vehicle controller of the present application;

[0032] Figure 8 Schematic diagram of the battery voltage detection unit in an embodiment of the protection circuit of an electric vehicle controller of the present application.

[0033] Icons: 11. Rectification unit; 12. First buck unit; 13. Second buck unit; 14. MCU controller unit; 15. PWM to DAC unit; 16. Electronic load unit; 17. Throttle signal detection unit; 18. Battery voltage detection unit. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations. In this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0036] Application overview

[0037] In the long downhill scenario of new energy electric vehicles, the inventor found through analysis of a large number of fault cases that: the existing technology relies on the passive shutdown mechanism of the lithium battery protection board. Although it can avoid overvoltage of the battery, it transfers the reverse charging current to the controller MOS tube, forming a "protection blind area". Specifically, when the protection board cuts off the charging path, the high-voltage reverse charging current generated by the motor due to inertia and continuous power generation has nowhere to be released, directly impacting the MOS tube and causing breakdown.

[0038] To address the above technical problems, the embodiment of the present application provides a protection circuit for an electric vehicle controller. Without changing the original vehicle circuit, it realizes "bypass protection" through signal acquisition and parallel connection with an electronic load. This design fundamentally solves the contradiction between "protection board shutdown" and "controller safety" in the long downhill scenario. By actively diverting instead of passively bearing, it can effectively avoid overvoltage breakdown of the controller MOS tube in the long downhill scenario.

[0039] After introducing the basic principle of the present application, the various non-limiting embodiments of the present application will be specifically introduced with reference to the accompanying drawings. Without conflict, the following embodiments and the various features in the embodiments can be combined with each other.

[0040] Exemplary Circuits and Devices

[0041] Please refer to Figure 1 , the protection circuit of an electric vehicle controller includes a rectification unit 11, a first buck unit 12, a second buck unit 13, an MCU controller unit 14, a PWM to DAC unit 15, and an electronic load unit 16 connected in series in sequence, and further includes a throttle signal detection unit 17 and a battery voltage detection unit 18 respectively connected to the MCU controller unit 14; the output end of the rectification unit 11 is connected to the electronic load unit 16, and the output end of the first buck unit 12 is connected to the electronic load unit 16. Among them, the input end of the rectification unit 11 is used to be connected to the three-phase lines of the electric vehicle motor, the input end of the throttle signal detection unit 17 is used to be connected to the throttle signal line of the electric vehicle, and the battery voltage detection unit 18 is used to be connected to the output end of the power supply battery of the electric vehicle.

[0042] In the above embodiments, the energy co-defense is achieved through the electronic load unit 16, which converts the reverse charging energy from passive reception to active management and control, breaks the energy island effect after the battery protection board is turned off, and establishes an independent discharge channel (motor three-phase line → rectifier unit 11 → electronic load unit 16). At the same time, through this circuit, the human-machine interaction signal (the signal detected by the throttle signal detection unit 17), the battery status signal (the signal detected by the battery voltage detection unit 18) and the fault cause (reverse charging energy) are combined, which can provide precise protection for the electric vehicle controller. Exemplarily, in the long downhill test with an 8% slope and a vehicle speed of 40 km / h, the controller failure rate is reduced from 32% in the traditional scheme to 0.5%, which can effectively protect the electric vehicle.

[0043] The following will specifically explain and illustrate each unit.

[0044] For the rectifier unit 11, the input end of the rectifier unit 11 is connected to the three-phase line of the electric vehicle motor. When the motor rotates, a three-phase AC voltage is generated. The rectifier unit 11 internally includes multiple rectifying elements such as diodes. Using the unidirectional conductivity of the diodes, the three-phase AC voltage is converted into a pulsating DC voltage, and then the pulsating DC voltage is smoothed into a relatively stable DC voltage, that is, the first DC voltage, through a filtering circuit (usually capacitor filtering), and is output to the subsequent electronic load unit 16 and the first buck unit 12.

[0045] Among them, the rectifier unit 11 converts the alternating current generated by the motor into direct current, provides a stable power input for other units in the entire protection circuit, and ensures that each unit can work normally. Moreover, when the electric vehicle motor enters the power generation mode under working conditions such as long downhill, a reverse charging current is generated. The rectifier unit 11 can timely and effectively process the alternating current generated by this reverse charging, avoid the alternating current from damaging other circuit components, and ensure the safety and stability of the circuit.

[0046] For the first buck unit 12, the input end of the first buck unit 12 receives the first DC voltage output by the rectifier unit 11, and the first DC voltage is bucked down to a second voltage (generally 12V) through an internal buck circuit (such as a linear voltage regulator circuit or a switching power supply buck circuit). The second buck unit 13 further bucks down the second voltage output by the first buck unit 12 to a third voltage (generally 3.3V) to meet the requirements of electronic components such as the MCU controller unit 14 that have specific requirements for the working voltage.

[0047] Among them, different electronic components in the protection circuit of the electric vehicle controller have different requirements for the working voltage. The step-down unit can gradually reduce the high voltage output by the rectification unit 11 to an appropriate level, ensuring that each component operates reliably in a stable voltage environment and avoiding damage to the components due to excessive or too low voltage. Through the two-stage reasonable step-down design of the first step-down unit 12 and the second step-down unit 13, the energy loss during the voltage conversion process is reduced, the energy utilization efficiency of the entire protection circuit is improved, and it helps to extend the cruising range of the electric vehicle.

[0048] For the throttle signal detection unit 17, the input end of the throttle signal detection unit 17 is connected to the throttle signal line of the electric vehicle. The throttle outputs an analog voltage signal by changing the internal resistance and other means, and this signal reflects the user's control intention for the driving speed of the electric vehicle. The throttle signal detection unit 17 internally includes signal conditioning circuits (such as amplification circuits, filtering circuits, etc.), which amplify, filter, and other process the collected analog voltage signal, remove noise and interference, and then convert the processed analog voltage signal into a digital signal and transmit it to the MCU controller unit 14.

[0049] Among them, collecting the throttle signal in real time and accurately enables the MCU controller unit 14 to timely understand the user's control demand for the speed of the electric vehicle, so as to make more reasonable protection decisions according to the actual working conditions. For example, when going down a long slope, if the user releases the throttle, the throttle signal will change, and the MCU controller unit 14 can judge that the vehicle may be in a downhill state based on this signal and make protection preparations in advance. Cooperating with multi-dimensional signals such as the throttle signal detection unit 17 and the battery voltage detection unit 18 can provide more comprehensive vehicle operation information for the MCU controller unit 14, improve the intelligent level of the protection circuit, and enable it to better adapt to the complex and changeable driving environment.

[0050] For the battery voltage detection unit 18, the battery voltage detection unit 18 is connected to the output end of the power supply battery of the electric vehicle. It uses the internal voltage detection circuit (such as a voltage dividing resistor network, an analog-to-digital converter, etc.) to collect the power supply voltage signal of the battery in real time and transmit this signal to the MCU controller unit 14. The voltage detection circuit divides the high voltage of the battery according to a certain ratio into a low voltage signal suitable for processing by the analog-to-digital converter, and the analog-to-digital converter then converts the analog voltage signal into a digital signal for the MCU controller unit 14 to analyze and process.

[0051] Among them, the power supply voltage of the battery is continuously monitored to provide real-time status information of the battery for the MCU controller unit 14. When the battery voltage changes due to reasons such as motor back charging, the MCU controller unit 14 can obtain this information in a timely manner, determine whether the battery is within the normal operating range, and avoid damaging the controller due to abnormal battery voltage. The signals collected by the battery voltage detection unit 18 and the throttle signal detection unit 17 are combined, enabling the MCU controller unit 14 to more accurately judge the operating conditions of the vehicle, and thus formulate a more reasonable protection strategy. For example, when it is detected that the battery voltage rises and the throttle signal indicates that the user has released the throttle, it can be determined that the vehicle is in a long downhill back charging state, and corresponding protection measures can be taken accordingly.

[0052] For the MCU controller unit 14, the MCU controller unit 14 is the core control component of the entire protection circuit. It receives the digital signals (throttle analog voltage information) transmitted by the throttle signal detection unit 17 and the digital signals (battery power supply voltage signals) transmitted by the battery voltage detection unit 18, and comprehensively analyzes and processes these signals according to the preset intelligent algorithms and programs (it can directly compare these signals with the corresponding thresholds to judge the operating state of the vehicle, that is, a conventional threshold judgment method can be used). By judging the operating state of the vehicle (such as whether it is in a long downhill, rapid acceleration, rapid braking and other working conditions), the MCU controller unit 14 outputs corresponding pulse width modulation (PWM) signals.

[0053] Among them, the MCU controller unit 14 can perform intelligent analysis and judgment based on multi-dimensional signals, and formulate the most suitable protection strategy for the current working conditions. Compared with the traditional single-parameter protection mechanism, the intelligent decision-making ability of the MCU controller unit 14 greatly improves the accuracy and reliability of the protection circuit, effectively avoiding misjudgment and missed judgment. Moreover, in the face of the complex and changeable working conditions during the driving of the electric vehicle, the MCU controller unit 14 can adjust the duty cycle of the PWM signal in real time, so as to accurately control the working state of the electronic load unit 16, realize the dynamic adjustment of the controller protection, and ensure that the controller can operate safely and stably under various working conditions.

[0054] For the PWM to DAC unit 15, the PWM to DAC unit 15 receives the PWM signal output by the MCU controller unit 14. The PWM signal is a digital signal with adjustable pulse width, and its duty cycle reflects the average level of the signal. The PWM to DAC unit 15 internally includes a filter circuit (such as an RC filter circuit), etc., which converts the PWM signal into an analog control signal. By integrating the PWM signal through the filter circuit, the high-frequency components of the pulse signal are removed, and a DC analog voltage signal proportional to the duty cycle of the PWM signal is obtained. This analog signal is used to drive the electronic load unit 16 to work.

[0055] Among them, the digital PWM signal output by the MCU controller unit 14 is converted into an analog control signal by the PWM-to-DAC unit 15, enabling the electronic load unit 16 to accurately adjust its working state according to the amplitude of the analog signal, meeting the precise control requirements for energy release. That is, through the precise conversion of PWM to an analog signal, the power of the electronic load unit 16 can be adjusted more delicately, achieving more accurate consumption of the motor back-charge current energy, and further improving the performance and reliability of the protection circuit.

[0056] For the electronic load unit 16, the electronic load unit 16 receives the analog control signal output by the PWM-to-DAC unit 15 and adjusts its own working state according to this signal. The electronic load unit 16 is usually composed of power devices (such as MOSFETs, IGBTs, etc.) and resistors and other components. By controlling the on and off of the power devices, the current magnitude on the resistor is adjusted, thereby achieving energy consumption. Exemplarily, the on-resistance of the MOS transistor can be adjusted according to the analog control signal to form a discharge loop. Then the calculation formula for the discharge power is: P is the discharge power, Rload is the load impedance corresponding to the electronic load unit 16, and Vrectified is the voltage output by the rectification unit 11. When the amplitude of the analog control signal increases, the energy consumed by the electronic load unit 16 increases; conversely, the consumed energy decreases. At the same time, the electronic load unit 16 also receives the first DC voltage output by the rectification unit 11 and the second voltage output by the first buck unit 12 as the working power supply.

[0057] Among them, after the battery protection board is turned off, the back-charge current generated by the motor cannot be released through the battery circuit. The electronic load unit 16 can intervene in time to provide an effective drainage path for the back-charge current. By consuming the excess energy generated by the back-charge current, the voltage and current inside the controller are reduced, avoiding overvoltage breakdown of the core components of the controller (such as MOS transistors), and protecting the safety of the controller. Moreover, according to the intelligent regulation of the MCU controller unit 14, the electronic load unit 16 can dynamically adjust the energy consumption according to different working conditions. In special working conditions such as long downhill slopes, the energy consumption is increased to ensure the safety of the controller; in normal driving conditions, a low-power consumption state is maintained to reduce energy waste and improve the battery life of the electric vehicle.

[0058] In summary, in this application, after the rectification unit 11 rectifies the alternating current reversely charged from the three-phase lines of the motor into direct current, it is directly connected to the electronic load unit 16 to form a discharge channel independent of the battery circuit. Moreover, the rectified high-voltage direct current is step-down by the first step-down unit 12 (exemplarily, a BUCK structure) and the second step-down unit 13 (exemplarily, an LDO structure) to provide a stable power supply for the MCU controller and the electronic load, ensuring continuous operation even when the lithium battery protection board is turned off. That is, the reverse charging current forms a closed loop from the three-phase lines of the motor → the rectification unit 11 → the electronic load unit 16 → the ground wire, avoiding energy accumulation at both ends of the MOS tube, and using the reverse charging energy to supply power to its own circuit (without relying on the battery), ensuring that the system can still operate during the off period of the protection board, achieving "continuous protection even when powered off".

[0059] Meanwhile, through the dual-parameter acquisition of the throttle signal detection unit 17 and the battery voltage detection unit 18, false operation during normal deceleration or short downhill can be reduced. Exemplarily, the discharge can be triggered only when the following conditions are met simultaneously: (1) Throttle voltage ≤ 0.8V (the driver clearly intends to go downhill); (2) The output voltage of the rectification unit 11 > the threshold (the reverse charging current intensity reaches the standard); (3) Battery voltage < the safety upper limit (to avoid overcharging caused by discharge).

[0060] In addition, the PWM to DAC unit 15 converts the digital PWM signal output by the MCU into an analog voltage signal to linearly control the on-resistance of the electronic load. Thus, because the MCU monitors the discharge loop current and voltage in real time and dynamically adjusts the PWM duty cycle, it can be ensured that the discharge power matches the reverse charging energy.

[0061] Furthermore, the throttle signal detection unit 17 is connected in parallel with the original vehicle throttle wire, and the battery voltage detection unit 18 is connected in parallel with the original vehicle battery terminal, without interfering with the original vehicle signal transmission. Compared with the traditional scheme of modifying the original vehicle circuit (such as adding a relay or cutting off the original line), the maintenance cost can be reduced.

[0062] For the convenience of those skilled in the art to understand, an exemplary program in the MCU controller is given as follows:[[]]END]]

[0063] #include"CW32F030.h"

[0064] / / Define the ADC channel number

[0065] #define ADC_CHANNEL_SPEED_CONTROL 0

[0066] #define ADC_CHANNEL_MOTOR_PHASE 1

[0067] #define ADC_CHANNEL_BATTERY_VOLTAGE 2

[0068] / / Define the threshold

[0069] #define DOWNHILL_THRESHOLD_ADC_VALUE 128

[0070] #define HIGH_REVERSE_CURRENT_THRESHOLD 512

[0071] #define BATTERY_OVERVOLTAGE_THRESHOLD 3000

[0072] / / Function declarations

[0073] void ADC_Init(void);

[0074] uint16_t Get_ADC_Value(uint8_t channel);

[0075] void Analyze_Data(void);

[0076] uint8_t Check_Downhill_Condition(void);

[0077] void Generate_RES_in_Signal(void);

[0078] void Adjust_IS_PWM_IN_Signal(void);

[0079] / / Global variables for storing ADC acquisition values

[0080] uint16_t speed_control_adc_value;

[0081] uint16_t motor_phase_adc_value;

[0082] uint16_t battery_voltage_adc_value;

[0083] int main(void)

[0084] {

[0085] / / Initialize basic configurations such as the system clock

[0086] / / Assume the system clock has been configured in the system initialization file

[0087] / / Initialize the ADC

[0088] ADC_Init();

[0089] while(1)

[0090] {

[0091] / / Obtain the ADC value of the speed control signal

[0092] speed_control_adc_value = Get_ADC_Value(ADC_CHANNEL_SPEED_CONTROL);

[0093] / / Obtain the ADC value of the motor phase line pulse voltage

[0094] motor_phase_adc_value = Get_ADC_Value(ADC_CHANNEL_MOTOR_PHASE);

[0095] / / Obtain the ADC value of the lithium battery supply voltage

[0096] battery_voltage_adc_value = Get_ADC_Value(ADC_CHANNEL_BATTERY_VOLTAGE);

[0097] / / Analyze the collected data

[0098] Analyze_Data();

[0099] / / Check if the long downhill condition is met

[0100] if(Check_Downhill_Condition())

[0101] {

[0102] / / Generate the RES-in signal to start the electronic load

[0103] Generate_RES_in_Signal();

[0104] / / Adjust the IS-PWM-IN signal to control the electronic load power

[0105] Adjust_IS_PWM_IN_Signal();

[0106] }

[0107] / / An appropriate delay can be added to avoid overly frequent sampling

[0108] for(volatile int i = 0; i < 100000; i++);

[0109] }

[0110] }

[0111] / / ADC initialization function

[0112] void ADC_Init(void)

[0113] {

[0114] / / Enable the ADC clock

[0115] RCC->AHBENR |= RCC_AHBENR_GPIOAEN_Msk;

[0116] RCC->APB1ENR |= RCC_APB1ENR_ADCEN_Msk;

[0117] / / Configure the GPIO pins corresponding to the ADC channels as analog inputs

[0118] GPIOA->ANALOG |= GPIO_ANALOG_ANALOG0_Msk | GPIO_ANALOG_ANALOG1_Msk | GPIO_ANALOG_ANALOG2_Msk;

[0119] / / Reset the ADC

[0120] ADC->CTR1 |= ADC_CTR1_RSTCAL_Msk;

[0121] while(ADC->CTR1 & ADC_CTR1_RSTCAL_Msk);

[0122] / / Calibrate the ADC

[0123] ADC->CTR1 |= ADC_CTR1_CAL_Msk;

[0124] while(ADC->CTR1 & ADC_CTR1_CAL_Msk);

[0125] / / ADC initialization settings

[0126] ADC->CTR1 &= ~ADC_CTR1_CONT_Msk; / / Single conversion mode

[0127] ADC->CTR1 &= ~ADC_CTR1_DMAC_Msk; / / Disable DMA

[0128] ADC->CTR2 &= ~ADC_CTR2_SCAN_Msk; / / Single-channel mode

[0129] ADC->SMPR = 0x07; / / Sampling time setting

[0130] / / Enable ADC

[0131] ADC->CTR1 |= ADC_CTR1_ADON_Msk;

[0132] }

[0133] / / Function to get ADC channel value

[0134] uint16_t Get_ADC_Value(uint8_t channel)

[0135] {

[0136] / / Select ADC channel

[0137] ADC->SQR3 = channel;

[0138] / / Start ADC conversion

[0139] ADC->CTR1 |= ADC_CTR1_SWSTART_Msk;

[0140] / / Wait for conversion to complete

[0141] while (!(ADC->SR & ADC_SR_EOC_Msk));

[0142] / / Read conversion result

[0143] return ADC->DR;

[0144] }

[0145] / / Data processing and analysis function

[0146] void Analyze_Data(void)

[0147] {

[0148] / / More complex data processing logic can be added here, such as filtering

[0149] / / Currently, simply get the acquired value

[0150] speed_control_adc_value = Get_ADC_Value(ADC_CHANNEL_SPEED_CONTROL);

[0151] motor_phase_adc_value = Get_ADC_Value(ADC_CHANNEL_MOTOR_PHASE);

[0152] battery_voltage_adc_value = Get_ADC_Value(ADC_CHANNEL_BATTERY_VOLTAGE);

[0153] }

[0154] / / Function to check long downhill condition

[0155] uint8_t Check_Downhill_Condition(void)

[0156] {

[0157] if(speed_control_adc_value <= DOWNHILL_THRESHOLD_ADC_VALUE &&

[0158] motor_phase_adc_value > HIGH_REVERSE_CURRENT_THRESHOLD &&

[0159] battery_voltage_adc_value > BATTERY_OVERVOLTAGE_THRESHOLD)

[0160] {

[0161] return 1;

[0162] }

[0163] return 0;

[0164] }

[0165] / / Function to generate RES-in signal

[0166] void Generate_RES_in_Signal(void)

[0167] {

[0168] / / Enable GPIO clock

[0169] RCC->AHBENR |= RCC_AHBENR_GPIOBEN_Msk;

[0170] / / Configure the GPIO pin as push - pull output

[0171] GPIOB->MODER &= ~GPIO_MODER_MODE0_Msk;

[0172] GPIOB->MODER |= GPIO_MODER_MODE0_0_Msk;

[0173] / / Output high level

[0174] GPIOB->BSRR = GPIO_BSRR_BS0_Msk;

[0175] }

[0176] / / Function to adjust the IS - PWM - IN signal

[0177] void Adjust_IS_PWM_IN_Signal(void)

[0178] {

[0179]

[0180] Next, the specific implementation manners of each rectification unit 11 will be described in detail by way of example.

[0181] Please refer to Figure 2 , based on the foregoing solution, in some implementation manners of the present application, the rectification unit 11 includes a diode D3, a diode D4, a diode D5, a diode D6, a diode D7, a diode D8, and a capacitor C5. Among them, the anodes of the diodes D3, D4, and D5 are all connected to the first end of the capacitor C5, the cathodes of the diodes D6, D7, and D8 are all connected to the second end of the capacitor C5, the anode of the diode D8 is connected to the cathode of the diode D3, the anode of the diode D7 is connected to the cathode of the diode D4, the anode of the diode D6 is connected to the cathode of the diode D5, the anode of the diode D8 is used to be connected to the U - phase line of the electric vehicle motor, the anode of the diode D7 is used to be connected to the V - phase line of the electric vehicle motor, and the anode of the diode D6 is used to be connected to the W - phase line of the electric vehicle motor.

[0182] In the above implementation, a full-bridge rectifier circuit is formed by six diodes and a capacitor, so that the three-phase alternating current generated by the motor can be converted into direct current. Among them, the capacitor C5 charges and stores energy during the rectification process, fills the troughs of the pulsating voltage, and makes the output voltage tend to be smooth. It should be noted that the UVW phases of the motor refer to the three-phase connection terminals of the motor, corresponding to three different connection terminals U, V, and W respectively.

[0183] Please refer to Figure 3 , based on the foregoing solution, in some implementations of the present application, the first buck unit 12 includes: a DC-DC buck chip U2, a diode D9, a resistor R25, a resistor R24, a resistor R23, an inductor L3, an inductor L4, a capacitor C6, a capacitor C7, and a capacitor C9. Among them, the pin VIN of the DC-DC buck chip U2 is connected to the cathode of the diode D6 through the inductor L3, the pin VIN of the DC-DC buck chip U2 is connected to the pin GND of the DC-DC buck chip U2 through the capacitor C6, the pin GND of the DC-DC buck chip U2 is connected to the pin FB of the DC-DC buck chip U2 through the resistor R25, the pin FB of the DC-DC buck chip U2 is connected to the pin VS of the DC-DC buck chip U2 after passing through the resistor R24 and the inductor L4, the pin IS of the DC-DC buck chip U2 is connected to the pin VS of the DC-DC buck chip U2 through the resistor R23, the pin VB of the DC-DC buck chip U2 is connected to the pin VC of the DC-DC buck chip U2 through the capacitor C7, the cathode of the diode D9 is connected to the pin VS of the DC-DC buck chip U2, and the cathode of the diode D9 is connected to the pin VS of the DC-DC buck chip U2 after passing through the capacitor C9 and the inductor L4.

[0184] In the above implementation, the VIN (input voltage pin) of the DC-DC buck chip U2 is connected to the cathode of the diode D6 through the inductor L3. The inductor L3 is used to smooth the input current and reduce the current ripple. At the same time, the VIN pin of the DC-DC buck chip U2 is connected to the GND (ground pin) through the capacitor C6. The capacitor C6 plays a role in input filtering, filtering out the high-frequency noise in the input voltage and providing a stable DC input voltage for the chip. Then, the GND pin of the DC-DC buck chip U2 is connected to the FB (feedback pin) through the resistor R25, forming part of the feedback network. The FB pin of the DC-DC buck chip U2 is connected to the VS (output voltage sampling pin) after passing through the resistor R24 and the inductor L4. The resistor R24 and the resistor R25 constitute a voltage division network, which is used to sample the output voltage and feed the sampled signal back to the DC-DC buck chip, so that the DC-DC buck chip can adjust the output voltage according to the feedback signal to achieve the voltage regulation function. The IS (current detection pin) of the DC-DC buck chip U2 is connected to the VS pin through the resistor R23. The resistor R23 is used to detect the output current. When the output current exceeds the set value, the chip can limit the current or provide protection through the internal circuit to prevent the circuit from being damaged due to overload. The VB (internal circuit power supply pin, which may be used for startup or internal circuit biasing in some chips) of the DC-DC buck chip U2 is connected to the VC through the capacitor C7. The capacitor C7 helps to stabilize the working voltage of the internal circuit of the chip and improve the stability and reliability of the circuit. The cathode of the diode D9 is connected to the VS pin. The diode D9 plays a freewheeling role, providing a path when the current in the inductor L4 tries to flow in the reverse direction, preventing the inductor from generating high-voltage spikes that may damage the chip or other components. At the same time, the VS pin of the DC-DC buck chip U2 is connected to itself after passing through the capacitor C9 and the inductor L4. The capacitor C9 and the inductor L4 together form an output filtering network, further smoothing the output voltage and reducing the ripple and noise of the output voltage.

[0185] In summary, it uses the DC-DC buck chip U2 to achieve efficient voltage conversion. Compared with linear regulators, it can significantly reduce energy loss and improve the power conversion efficiency. Moreover, through the feedback network and the output filtering network, this buck unit can provide a stable and low-ripple output voltage to meet the requirements of loads with high power quality. By adjusting the values of the feedback resistors (resistor R24 and resistor R25), the output voltage can be easily set to meet the voltage requirements of different loads. At the same time, the parameter selection of capacitors and inductors also has a certain degree of flexibility and can be optimized according to specific application scenarios.

[0186] Exemplarily, the model of the DC-DC buck chip U2 can be EG1198.

[0187] Please refer to Figure 3, based on the foregoing solution, in some implementation manners of the present application, the second step-down unit 13 includes: a linear voltage regulator chip U5, an inductor L5, a capacitor C8, a capacitor C10, and a capacitor C11. Among them, the VIN pin of the linear voltage regulator chip U5 is connected to the VS pin of the DC-DC step-down chip U2 through the inductor L4. The capacitors C8, C10, and C9 are connected in parallel in pairs. The VIN pin of the linear voltage regulator chip U5 is connected to the GND pin of the linear voltage regulator chip U5 through the capacitor C10 and the inductor L5. The VOUT pin of the linear voltage regulator chip U5 is connected to the GND pin of the linear voltage regulator chip U5 through the capacitor C11.

[0188] In the above implementation manner, the VIN (input voltage pin) of the linear voltage regulator chip U5 is connected to the VS (output voltage sampling pin, serving as the front-stage output terminal here) of the previous-stage DC-DC step-down chip U2 through the inductor L4. The inductor L4 has played a certain filtering role in the first step-down unit 12. This connection enables the second step-down unit 13 to receive the voltage signal from the first step-down unit 12. At the same time, the inductor L4 can perform preliminary smoothing processing on the input signal to reduce high-frequency interference. The capacitors C8, C10, and C9 are connected in parallel and are connected near the VIN pin to further filter the input voltage and filter out high-frequency noise and ripple. At the same time, the VIN pin of the linear voltage regulator chip U5 is connected to the GND (ground pin) of the linear voltage regulator chip U5 through the capacitor C10 and the inductor L5. The inductor L5 and the parallel capacitors C8 and C10 together form an input filter network. The inductor L5 can further smooth the input current and reduce the impact of current mutation on the chip. The capacitor is responsible for filtering out noises of different frequencies and providing a stable and clean input voltage for the chip. The VOUT (output voltage pin) of the linear voltage regulator chip U5 is connected to the GND pin of the linear voltage regulator chip U5 through the capacitor C11. The capacitor C11 serves as an output filter capacitor to filter the voltage output by the linear voltage regulator chip U5, reduce the ripple and noise of the output voltage, and make the output voltage more stable, meeting the requirements of the subsequent load for the power quality.

[0189] Exemplarily, the model of the second step-down unit 13 can adopt AMS1117-3.3, so as to be able to accurately regulate the input voltage, and the ripple and noise of the output voltage are extremely low, effectively avoiding interference to the subsequent load circuit caused by voltage fluctuation.

[0190] Please refer to Figure 4, based on the foregoing solution, in some implementation manners of the present application, the MCU controller unit 14 includes: a processor chip U4 of the CW32F003E4P7 model, a capacitor C12, a resistor R26, a light-emitting diode LED1, and a terminal block H2 (used as a download interface). Among them, the pin VSS of the processor chip U4 is connected to the pin VDD of the processor chip U4 through the capacitor C12, the pin VDD of the processor chip U4 is connected to the pin VOUT of the linear voltage regulator chip U5, the terminal 1 of the terminal block H2 is connected to the pin VDD of the processor chip U4, the terminal 2 of the terminal block H2 is connected to the pin PA02 of the processor chip U4, the terminal 3 of the terminal block H2 is connected to the pin PA05 of the processor chip U4, the pin VDD of the processor chip U4 is connected to the anode of the light-emitting diode LED1 through the resistor R26, and the cathode of the light-emitting diode LED1 is connected to the pin PB05 of the processor chip U4.

[0191] Please refer to Figure 5 , based on the foregoing solution, in some implementation manners of the present application, the PWM to DAC unit 15 includes: a capacitor C13, a capacitor C14, a capacitor C15, a resistor R27, and a resistor R28. Among them, one end of the capacitor C13 is connected to the pin PB02 of the processor chip U4, and the other end is grounded through the resistor R27, the resistor R28, and the capacitor C15, and the common end of the resistor R27 and the resistor R28 is grounded through the capacitor C14.

[0192] In the above implementation, one end of the capacitor C13 is connected to the pin PB02 of the processor chip U4. The pin PB02 serves as the output pin of the PWM signal, introducing the PWM signal generated by the MCU into the PWM-to-DAC unit 15. The other end of the capacitor C13 serves as the starting point of the signal processing path and is connected to the subsequent resistor and capacitor network. The capacitor C13 plays a certain coupling role here, coupling the PWM signal output by the MCU controller unit 14 into the subsequent conversion circuit, and at the same time having a certain inhibitory effect on the high-frequency interference in the signal, reducing the noise introduced during signal transmission. The other end of the capacitor C13 is grounded through the resistors R27, R28 and the capacitor C15. The resistors R27 and R28 are connected in series and together with the capacitor C15 form a second-order RC low-pass filter network. The PWM signal is a digital pulse signal that contains rich high-frequency harmonic components. Through this RC low-pass filter network, the high-frequency part of the PWM signal can be effectively filtered out, and only its DC component (average value) is retained, thereby realizing the conversion of the PWM signal to an analog voltage signal. The resistance values of the resistors R27 and R28 will affect the cut-off frequency and output impedance of the filter, and thus affect the quality and driving ability of the converted analog voltage signal. The common end of the resistors R27 and R28 is grounded through the capacitor C14. The capacitor C14 and the resistors R27, R28 form an additional filter branch to further filter and smooth the signal. It can filter out some specific frequency noises that are not completely filtered out in the main RC filter network, improve the purity of the output analog voltage signal, and reduce the impact of ripple and noise on the subsequent circuit.

[0193] Compared with dedicated DAC chips, the PWM-to-DAC unit 15 only uses simple and low-cost components such as capacitors and resistors, greatly reducing the hardware cost. The circuit structure of this unit is simple and clear, consisting of only a few capacitors and resistors, with a small number of components and clear connection relationships. This simple circuit structure not only reduces the complexity of hardware design, reduces the mutual interference between components, but also improves the reliability and stability of the circuit. At the same time, the simple circuit is also convenient for troubleshooting and maintenance, reducing the maintenance cost of the product.

[0194] Please refer to Figure 6, based on the foregoing solution, in some implementation manners of the present application, the electronic load unit 16 includes: comparator U1.1, comparator U3.2, triode Q2, triode Q3, triode Q4, triode Q5, MOS transistor Q1, MOS transistor Q6, inductor L1, inductor L2, resistor R1, resistor R9, resistor R7, resistor R8, resistor R5, resistor R6, resistor R4, resistor R3, resistor R2, resistor R22, resistor R21, resistor R20, resistor R18, resistor R19, resistor R16, resistor R17, resistor R14, resistor R15, capacitor C10, capacitor C18 and capacitor C4. Among them, the non-inverting input terminal of comparator U1.1 is connected to the common terminal of resistor R28 and capacitor C15. The non-inverting input terminal of comparator U1.1 is connected to the output terminal of comparator U1.1 through the parallel-connected capacitor C18 and resistor R1. The power input terminal of comparator U1.1 is connected to the pin VS of DC-DC buck chip U2 through inductor L4. The power input terminal of comparator U1.1 is grounded through capacitor C10. The inverting input terminal of comparator U1.1 is grounded through resistor R9 and resistor R2. The output terminal of comparator U1.1 is connected to the base of triode Q2. The base of triode Q2 is connected to the emitter of triode Q2 through resistor R8. The base of triode Q2 is connected to the pin PB03 of processor chip U4 through resistor R7. The collector of triode Q2 is connected to the base of triode Q3 through resistor R4. The base of triode Q3 is connected to the emitter of triode Q3 through resistor R6. The emitter of triode Q3 is connected to the pin VS of DC-DC buck chip U2 through inductor L4. The collector of triode Q3 is connected to the gate of MOS transistor Q1 through resistor R4. The gate of MOS transistor Q1 is connected to the source of MOS transistor Q1 through resistor R3. The drain of MOS transistor Q1 is connected to the cathode of diode D6. The drain of MOS transistor Q1 is grounded through resistor R2 and inductor L1.The non-inverting input terminal of comparator U3.2 is connected to the common terminal of resistor R28 and capacitor C15. The non-inverting input terminal of comparator U3.2 is connected to the output terminal of comparator U3.2 through the parallel-connected capacitor C15 and resistor R4. The inverting input terminal of comparator U3.2 is grounded through resistor R14 and resistor R22. The output terminal of comparator U3.2 is connected to the base of transistor Q5. The base of transistor Q5 is connected to the emitter of transistor Q5 through resistor R16. The base of transistor Q5 is connected to pin PB03 of processor chip U4 through resistor R17. The collector of transistor Q5 is connected to the base of transistor Q4 through resistor R19. The base of transistor Q4 is connected to the emitter of transistor Q4 through resistor R18. The emitter of transistor Q4 is connected to pin VS of DC-DC buck chip U2 through inductor L4. The collector of transistor Q4 is connected to the gate of MOS transistor Q6 through resistor R20. The gate of MOS transistor Q6 is connected to the source of MOS transistor Q6 through resistor R21. The drain of MOS transistor Q6 is connected to the cathode of diode D6. The drain of MOS transistor Q6 is grounded through resistor R22 and inductor L2.

[0195] In the above implementation, the inverting input terminal of comparator U1.1 is grounded through resistor R9 and resistor R2. Resistor R9 and resistor R2 form a voltage division circuit to set a reference threshold voltage for comparator U1.1. When the reference signal voltage at the non-inverting input terminal is higher than the threshold voltage at the inverting input terminal, comparator U1.1 outputs a high level; otherwise, it outputs a low level. The output terminal of comparator U1.1 is connected to the base of transistor Q2 to introduce the output signal of the comparator into transistor Q2 for amplification. The base of transistor Q2 is connected to the emitter of transistor Q2 through resistor R8 to stabilize the operating point of the transistor. At the same time, the base of transistor Q2 is connected to pin PB03 of processor chip U4 through resistor R7. Processor chip U4 can output a control signal through pin PB03 to intervene in the conduction state of transistor Q2 to achieve flexible control of the circuit. The collector of transistor Q2 is connected to the base of transistor Q3 through resistor R4 to further transmit the amplified signal to transistor Q3 for secondary amplification. The base of transistor Q3 is connected to the emitter of transistor Q3 through resistor R6 to stabilize its operating point. The emitter of transistor Q3 is connected to pin VS of DC-DC buck chip U2 through inductor L4 to obtain power. The collector of transistor Q3 is connected to the gate of MOS transistor Q1 through resistor R4 to send the amplified drive signal to the gate of MOS transistor Q1 to control the conduction degree of MOS transistor Q1.

[0196] The gate of MOS transistor Q1 is connected to the source of MOS transistor Q1 through resistor R3. Resistor R3 serves to limit current and stabilize the gate voltage, preventing damage to the MOS transistor due to excessive gate voltage. When the drive signal output by transistor Q3 acts on the gate of MOS transistor Q1, it controls the conduction and cutoff of MOS transistor Q1, thereby controlling the magnitude of the load current. The drain of MOS transistor Q1 is connected to the cathode of diode D6, and diode D6 serves to prevent current backflow and protect circuit components. The drain of MOS transistor Q1 is grounded through resistor R2 and inductor L1. Resistor R2 acts as a sampling resistor, converting the load current into a voltage signal for feedback control; inductor L1 serves to smooth the current and reduce current fluctuations.

[0197] Comparator U3.2, transistor Q5, transistor Q4, MOS transistor Q6, and related resistors and inductors form another load control channel that is symmetric to the circuit related to U1.1. Its working principle is similar to that of the circuit related to U1.1. By setting different reference thresholds through different voltage-dividing resistors (resistors R14 and R22), the conduction degree of MOS transistor Q6 can be independently controlled to achieve the adjustment of the load current of the other path. The two load channels can work independently or cooperatively, providing different load current combinations according to actual requirements.

[0198] In summary, by comparing the analog voltage signal output by the front-stage PWM to DAC unit 15 with the set reference threshold through a comparator, and then through the amplification and drive of transistors and MOS transistors, the conduction degree of the MOS transistor can be precisely controlled, thereby achieving precise adjustment of the load current. This precise control ability enables the electronic load unit 16 to simulate various different load characteristics and meet the requirements for load current accuracy in different test and application scenarios.

[0199] Please refer to Figure 7 Based on the foregoing solution, in some implementation manners of the present application, the throttle signal detection unit 17 includes: a terminal block J4, a diode D10, a capacitor C17, a capacitor C16, a resistor R29, a resistor R30, and a resistor R31. Among them, the terminal block J4 is used to connect to the throttle signal line of the electric vehicle. Terminal 2 of the terminal block J4 is connected to terminal 3 of the terminal block J4 through resistor R30. Terminal 2 of the terminal block J4 is connected to terminal 3 of the terminal block J4 through resistor R29 and capacitor C17. The common terminal of resistor R29 and capacitor C17 is connected to pin PA06 of the processor chip U4. Terminal 1 of the terminal block J4 is grounded through capacitor C16. Terminal 1 of the terminal block J4 is connected to pin VOUT of the linear voltage regulator chip U5 through resistor R31. The anode of diode D10 is connected to pin VOUT of the linear voltage regulator chip U5, and the cathode of diode D10 is connected to terminal 1 of the terminal block J4.

[0200] The terminal block J4 serves as the interface between the throttle signal and the detection unit, and its terminals are used to connect to the throttle signal wires of the electric vehicle. It should be noted that the throttle signal wires output an analog voltage signal that varies with the rotation angle of the throttle, and this signal reflects the rider's intention to control the speed of the electric vehicle. Terminal 1 of the terminal block J4 is connected to the pin VOUT of the linear voltage regulator chip U5 through the resistor R31. The linear voltage regulator chip U5 provides a stable operating voltage for the throttle signal wires to ensure that the throttle can output signals normally. At the same time, the anode of the diode D10 is connected to the pin VOUT of the linear voltage regulator chip U5, and the cathode is connected to terminal 1 of the terminal block J4. The diode D10 plays a reverse protection role to prevent damage to the linear voltage regulator chip U5 caused by abnormal external voltages (such as accidental reverse connection of the throttle signal wires). Terminal 1 of the terminal block J4 is grounded through the capacitor C16. The capacitor C16 filters the power supply output by the linear voltage regulator chip U5, filtering out high-frequency noise and ripple in the power supply, providing a clean and stable power supply environment for the throttle signal wires, and improving the accuracy of the throttle signal. Terminals 2 and 3 of the terminal block J4 are the output terminals of the throttle signal. Terminal 2 is connected to terminal 3 through the resistor R30, and at the same time, terminal 2 is also connected to terminal 3 through the resistor R29 and the capacitor C17. These two paths form a collection network for the throttle signal. The resistor R30 plays a certain current limiting and voltage dividing role, while the resistor R29 and the capacitor C17 form an RC filter circuit. The common terminal of the resistor R29 and the capacitor C17 is connected to the pin PA06 of the processor chip U4, sending the filtered throttle signal into the processor chip. The RC filter circuit can effectively filter out high-frequency interference and noise in the throttle signal, making the signal received by the processor chip smoother and more stable, thereby improving the accuracy and reliability of the throttle signal detection.

[0201] In summary, by filtering the throttle signal through the RC filter circuit, high-frequency noise and interference in the signal can be effectively removed, making the throttle signal received by the processor chip cleaner and more stable. The reverse protection function of the diode D10 can effectively prevent damage to the linear voltage regulator chip U5 caused by accidental reverse connection of the throttle signal wires or other abnormal voltage conditions, protecting the power supply part of the entire detection unit, improving the reliability and stability of the circuit, and reducing the risk of circuit failures.

[0202] Please refer to Figure 8, based on the foregoing solution, in some implementation manners of the present application, the battery voltage detection unit 18 includes: a capacitor C2, a resistor R32, a resistor R33, a resistor R34, and a resistor R35. Among them, one end of the resistor R35 is grounded and used to connect to the negative electrode of the power supply battery of the electric vehicle, and the other end is sequentially connected to the positive electrode of the power supply battery of the electric vehicle through the resistor R34, the resistor R33, and the resistor R32. The capacitor C2 is connected in parallel with the resistor R35, and the common terminal of the resistor R35 and the resistor R34 is connected to the pin PA04 of the processor chip U4.

[0203] In the above implementation manner, one end of the resistor R35 is grounded and connected to the negative electrode of the power supply battery of the electric vehicle, and the other end is sequentially connected to the positive electrode of the battery through the resistor R34, the resistor R33, and the resistor R32. These four resistors form a series voltage-dividing resistor network, whose function is to reduce the high voltage of the battery proportionally to a voltage range that the processor chip can safely receive and process. The capacitor C2 is connected in parallel with the resistor R35. The capacitor C2 has a filtering effect, and in the circuit, it can absorb the high-frequency noise and ripple in the circuit. Since there may be certain fluctuations in the output voltage of the battery or noise is generated due to external electromagnetic interference, these noises will be superimposed on the voltage signal after voltage division, affecting the accurate detection of the battery voltage by the processor chip U4. The capacitor C2 can bypass these noises, making the voltage signal transmitted to the pin PA04 of the processor chip U4 more stable and accurate, and reducing the measurement error. The common terminal of the resistor R35 and the resistor R34 is connected to the pin PA04 of the processor chip U4, and the voltage signal at this common terminal is the battery voltage sampling signal after voltage division and filtering processing. The processor chip reads this voltage signal through the pin PA04 and uses the internal analog-to-digital converter (ADC) to convert the analog voltage signal into a digital signal for subsequent operations and processing, such as calculating the remaining power of the battery, determining whether the battery is overcharged or over-discharged, etc.

[0204] The embodiment of the present application further provides a protection device for an electric vehicle controller, which is a protection circuit of an electric vehicle controller as described above. It can be made into a protection device for an electric vehicle controller by encapsulating the circuit board provided with the protection circuit of the electric vehicle controller into a housing, which is beneficial for users to use and is convenient and fast.

[0205] For those skilled in the art, it is obvious that the present application is not limited to the details of the above-described exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present application is defined by the appended claims rather than the above description. Accordingly, all changes that fall within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present application. Any reference signs in the claims should not be construed as limiting the claims concerned.

Claims

1. A protection circuit for an electric vehicle controller, characterized in that It includes a rectification unit, a first step-down unit, a second step-down unit, an MCU controller unit, a PWM-to-DAC unit, and an electronic load unit connected in series in sequence, and also includes a throttle signal detection unit and a battery voltage detection unit respectively connected to the MCU controller unit; the output end of the rectification unit is connected to the electronic load unit, and the output end of the first step-down unit is connected to the electronic load unit; wherein, the input end of the rectification unit is used to be connected to the three-phase lines of the electric vehicle motor, the input end of the throttle signal detection unit is used to be connected to the throttle signal line of the electric vehicle, and the battery voltage detection unit is used to be connected to the output end of the power supply battery of the electric vehicle.

2. The circuit according to claim 1, wherein The rectification unit includes diode D3, diode D4, diode D5, diode D6, diode D7, diode D8, and capacitor C5; wherein, the anodes of diode D3, diode D4, and diode D5 are all connected to the first end of capacitor C5, the cathodes of diode D6, diode D7, and diode D8 are all connected to the second end of capacitor C5, the anode of diode D8 is connected to the cathode of diode D3, the anode of diode D7 is connected to the cathode of diode D4, the anode of diode D6 is connected to the cathode of diode D5, the anode of diode D8 is used to be connected to the U-phase line of the electric vehicle motor, the anode of diode D7 is used to be connected to the V-phase line of the electric vehicle motor, and the anode of diode D6 is used to be connected to the W-phase line of the electric vehicle motor.

3. The circuit according to claim 2, wherein The first step-down unit includes: DC-DC step-down chip U2, diode D9, resistor R25, resistor R24, resistor R23, inductor L3, inductor L4, capacitor C6, capacitor C7, and capacitor C9; wherein, the VIN pin of the DC-DC step-down chip U2 is connected to the cathode of diode D6 through the inductor L3, the VIN pin of the DC-DC step-down chip U2 is connected to the GND pin of the DC-DC step-down chip U2 through the capacitor C6, the GND pin of the DC-DC step-down chip U2 is connected to the FB pin of the DC-DC step-down chip U2 through the resistor R25, the FB pin of the DC-DC step-down chip U2 is connected to the VS pin of the DC-DC step-down chip U2 after passing through the resistor R24 and the inductor L4, the IS pin of the DC-DC step-down chip U2 is connected to the VS pin of the DC-DC step-down chip U2 through the resistor R23, the VB pin of the DC-DC step-down chip U2 is connected to the VC pin of the DC-DC step-down chip U2 through the capacitor C7, the cathode of diode D9 is connected to the VS pin of the DC-DC step-down chip U2, and the cathode of diode D9 is connected to the VS pin of the DC-DC step-down chip U2 after passing through the capacitor C9 and the inductor L4.

4. The circuit according to claim 3, characterized in that, The second step-down unit includes: linear voltage regulator chip U5, inductor L5, capacitor C8, capacitor C10, and capacitor C11; Among them, the pin VIN of the linear voltage regulator chip U5 is connected to the pin VS of the DC-DC buck chip U2 through the inductor L4. The capacitors C8, C10, and C9 are connected in parallel in pairs. The pin VIN of the linear voltage regulator chip U5 is connected to the pin GND of the linear voltage regulator chip U5 after passing through the capacitor C10 and the inductor L5. The pin VOUT of the linear voltage regulator chip U5 is connected to the pin GND of the linear voltage regulator chip U5 through the capacitor C11.

5. The circuit according to claim 4, characterized in that, The MCU control unit includes: a processor chip U4 of the CW32F003E4P7 model, a capacitor C12, a resistor R26, a light-emitting diode LED1, and a terminal block H2; Among them, the pin VSS of the processor chip U4 is connected to the pin VDD of the processor chip U4 through the capacitor C12. The pin VDD of the processor chip U4 is connected to the pin VOUT of the linear voltage regulator chip U5. The terminal 1 of the terminal block H2 is connected to the pin VDD of the processor chip U4. The terminal 2 of the terminal block H2 is connected to the pin PA02 of the processor chip U4. The terminal 3 of the terminal block H2 is connected to the pin PA05 of the processor chip U4. The pin VDD of the processor chip U4 is connected to the anode of the light-emitting diode LED1 through the resistor R26. The cathode of the light-emitting diode LED1 is connected to the pin PB05 of the processor chip U4.

6. The circuit according to claim 5, characterized in that, The PWM to DAC unit includes: a capacitor C13, a capacitor C14, a capacitor C15, a resistor R27, and a resistor R28; Among them, one end of the capacitor C13 is connected to the pin PB02 of the processor chip U4, and the other end is grounded after passing through the resistor R27, the resistor R28, and the capacitor C15. The common end of the resistor R27 and the resistor R28 is grounded through the capacitor C14.

7. The circuit according to claim 6, characterized in that, The electronic load unit includes: a comparator U1.1, a comparator U3.2, a triode Q2, a triode Q3, a triode Q4, a triode Q5, a MOS tube Q1, a MOS tube Q6, an inductor L1, an inductor L2, a resistor R1, a resistor R9, a resistor R7, a resistor R8, a resistor R5, a resistor R6, a resistor R4, a resistor R3, a resistor R2, a resistor R22, a resistor R21, a resistor R20, a resistor R18, a resistor R19, a resistor R16, a resistor R17, a resistor R14, a resistor R15, a capacitor C10, a capacitor C18, and a capacitor C4; Among them, the non-inverting input terminal of the comparator U1.1 is connected to the common terminal of the resistor R28 and the capacitor C15. The non-inverting input terminal of the comparator U1.1 is connected to the output terminal of the comparator U1.1 through the parallel-connected capacitor C18 and resistor R1. The power input terminal of the comparator U1.1 is connected to the pin VS of the DC-DC buck chip U2 through the inductor L4. The power input terminal of the comparator U1.1 is grounded through the capacitor C10. The inverting input terminal of the comparator U1.1 is grounded through the resistor R9 and the resistor R2. The output terminal of the comparator U1.1 is connected to the base of the triode Q2. The base of the triode Q2 is connected to the emitter of the triode Q2 through the resistor R8. The base of the triode Q2 is connected to the pin PB03 of the processor chip U4 through the resistor R7. The collector of the triode Q2 is connected to the base of the triode Q3 through the resistor R4. The base of the triode Q3 is connected to the emitter of the triode Q3 through the resistor R6. The emitter of the triode Q3 is connected to the pin VS of the DC-DC buck chip U2 through the inductor L4. The collector of the triode Q3 is connected to the gate of the MOS transistor Q1 through the resistor R4. The gate of the MOS transistor Q1 is connected to the source of the MOS transistor Q1 through the resistor R3. The drain of the MOS transistor Q1 is connected to the cathode of the diode D6. The drain of the MOS transistor Q1 is grounded through the resistor R2 and the inductor L1; The non-inverting input terminal of the comparator U3.2 is connected to the common terminal of the resistor R28 and the capacitor C15. The non-inverting input terminal of the comparator U3.2 is connected to the output terminal of the comparator U3.2 through the parallel-connected capacitor C15 and resistor R4. The inverting input terminal of the comparator U3.2 is grounded through the resistor R14 and the resistor R22. The output terminal of the comparator U3.2 is connected to the base of the triode Q5. The base of the triode Q5 is connected to the emitter of the triode Q5 through the resistor R16. The base of the triode Q5 is connected to the pin PB03 of the processor chip U4 through the resistor R17. The collector of the triode Q5 is connected to the base of the triode Q4 through the resistor R19. The base of the triode Q4 is connected to the emitter of the triode Q4 through the resistor R18. The emitter of the triode Q4 is connected to the pin VS of the DC-DC buck chip U2 through the inductor L4. The collector of the triode Q4 is connected to the gate of the MOS transistor Q6 through the resistor R20. The gate of the MOS transistor Q6 is connected to the source of the MOS transistor Q6 through the resistor R21. The drain of the MOS transistor Q6 is connected to the cathode of the diode D6. The drain of the MOS transistor Q6 is grounded through the resistor R22 and the inductor L2.

8. The circuit according to claim 5, wherein The throttle signal detection unit includes: a terminal block J4, a diode D10, a capacitor C17, a capacitor C16, a resistor R29, a resistor R30, and a resistor R31; Among them, the terminal block J4 is used to connect to the throttle signal wire of the electric vehicle. Terminal 2 of the terminal block J4 is connected to terminal 3 of the terminal block J4 through the resistor R30. Terminal 2 of the terminal block J4 is connected to terminal 3 of the terminal block J4 after passing through the resistor R29 and the capacitor C17. The common terminal of the resistor R29 and the capacitor C17 is connected to pin PA06 of the processor chip U4. Terminal 1 of the terminal block J4 is grounded through the capacitor C16. Terminal 1 of the terminal block J4 is connected to pin VOUT of the linear voltage regulator chip U5 through the resistor R31. The anode of the diode D10 is connected to pin VOUT of the linear voltage regulator chip U5, and the cathode of the diode D10 is connected to terminal 1 of the terminal block J4.

9. The circuit according to claim 5, characterized in that, The battery voltage detection unit includes: a capacitor C2, a resistor R32, a resistor R33, a resistor R34, and a resistor R35; Among them, one end of the resistor R35 is grounded and used to connect to the negative electrode of the power supply battery of the electric vehicle, and the other end is used to connect to the positive electrode of the power supply battery of the electric vehicle after passing through the resistor R34, the resistor R33, and the resistor R32 in sequence. The capacitor C2 is connected in parallel with the resistor R35. The common terminal of the resistor R35 and the resistor R34 is connected to pin PA04 of the processor chip U4.

10. A protection device for an electric vehicle controller, characterized in that, It includes a protection circuit for an electric vehicle controller as described in any one of claims 1-9.

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