An overcurrent detection and protection circuit and system for an electric vehicle intelligent controller

Abstract

This invention discloses an overcurrent detection and protection circuit and system for an intelligent controller of an electric vehicle. The overcurrent detection and protection circuit includes a main control MCU circuit, a three-phase drive output circuit, a power switch circuit, a high-precision current sampling circuit, a hardware-based high-speed overcurrent detection circuit, a software-based graded current limiting and control circuit, a timing-based anti-misjudgment filtering circuit, a fault self-locking shutdown circuit, a temperature-linked protection circuit, and a power-off energy storage memory circuit. The three-phase drive output circuit is connected to the signal terminal of the main control MCU circuit, and the hardware-based high-speed overcurrent detection circuit is electrically connected to the output terminal of the current sampling circuit. This invention adopts a dual-path overcurrent protection architecture (hardware and software). The hardware circuit requires no MCU intervention, providing microsecond-level response to short-circuit ultra-high currents, completely solving the problems of delayed software protection response and easy device breakdown. The software-based graded current limiting adapts to common overload conditions, flexibly reducing power and clamping current, avoiding abrupt shutdowns and significantly improving riding smoothness.

Description

Technical Field

[0001] This invention relates to the field of controller overcurrent detection and protection circuit technology, specifically to an overcurrent detection and protection circuit and system for an intelligent controller of an electric vehicle. Background Technology

[0002] As the core of the vehicle's power drive, the electric vehicle controller is prone to overcurrent under conditions such as motor stall, starting shock, overload, phase line short circuit, and aging and leakage of the wiring. Excessive current can directly burn out the power MOSFET, driver chip, and PCB circuit, and is the main cause of controller damage. Therefore, a high-precision, high-response, and high-stability overcurrent detection and protection circuit is the key to ensuring the safe operation of electric vehicles. People usually connect the controller overcurrent detection and protection circuit in series on one side of the electric vehicle controller to detect the current passing through the controller in real time.

[0003] However, traditional controller overcurrent detection and protection circuits have the following drawbacks: Traditional controller overcurrent detection and protection circuits mostly rely on MCU software for single detection and protection, depending on program calculation and judgment. The response speed is slow, and it cannot block microsecond-level instantaneous short circuits and large impact currents in time, which can easily cause power devices to break down and burn out instantly. Summary of the Invention

[0004] The purpose of this invention is to provide an overcurrent detection and protection circuit and system for an intelligent controller of an electric vehicle, in order to solve the problem that most traditional controller overcurrent detection and protection circuits mentioned in the background art rely solely on MCU software for detection and protection, depend on program calculation and judgment, have a slow response speed, and cannot timely block microsecond-level instantaneous short circuits and impact currents, which can easily cause power devices to break down and burn out instantly.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an overcurrent detection and protection circuit for an electric vehicle intelligent controller, comprising an overcurrent detection and protection circuit. The overcurrent detection and protection circuit includes a main control MCU circuit, a three-phase drive output circuit, a power switch tube circuit, a high-precision current sampling circuit, a hardware ultra-fast overcurrent detection circuit, a software graded current limiting and control circuit, a timing anti-misjudgment filter circuit, a fault self-locking shutdown circuit, a temperature linkage protection circuit, and a power failure energy storage memory circuit. The three-phase drive output circuit is connected to the signal terminal of the main control MCU circuit, and the hardware high-speed overcurrent detection circuit is electrically connected to the output terminal of the current sampling circuit. The main control MCU circuit contains an MCU chip, which is an STM32F103C8T6. Pins 47, 8, 23, and 35 of the MCU chip are all grounded. The three-phase drive output circuit includes diode D1, capacitor C1, capacitor C2, capacitor C3, capacitor C4, resistor R1, resistor R2, and diode D2. The power switch circuit includes a resistor R4, a diode D3, a transistor Q1, a resistor R3, and a capacitor C5. The high-precision current sampling circuit includes an interface P1, resistors R5, R6, and R7, capacitors C6 and C7, and an amplifier U1A. The amplifier U1A is an LM2904D, and the interface P1 is an XH2.54-2P. The hardware-based high-speed overcurrent detection circuit includes an integrated circuit U1, resistors R8, R9, R10, and R11, transistors Q2 and Q3, and a capacitor C8. The software-defined hierarchical current limiting control circuit includes resistors R12, R13, R14, R15, and R16, capacitors C9 and C10, diode D4, transistor Q4, and transistor Q5. The timing misjudgment prevention filter circuit includes an inductor L1 and a capacitor C11. The temperature linkage protection circuit includes resistors R17, R18, and R19, and capacitor C12. The power-off energy storage memory circuit includes interface CN1, interface CN2, resistors R20, R21, R22, R23, R24, R25 and transistor Q5.

[0006] Furthermore, the main control MCU circuit is the core control unit of the circuit, used to output PWM drive signals, acquire real-time current conditions, run graded overcurrent protection algorithms, and execute current limiting and shutdown logic; the three-phase drive output circuit is used to amplify and isolate the drive signal to drive the power switch circuit at the back end; the power switch circuit is used to realize the three-phase commutation and power output of the motor; the high-precision current sampling circuit is used to synchronously acquire the total bus current and three-phase current, and output accurate analog sampling signals; the hardware ultra-fast overcurrent detection circuit operates independently of the main control MCU, used to identify instantaneous short circuits and ultra-large impact overcurrent faults at the microsecond level, and directly output hardware shutdown signals; the software graded current limiting and control circuit has built-in multi-level overcurrent thresholds, used to target minor overloads, moderate overcurrents, and continuous overloads. The operating condition execution software features flexible current limiting and power reduction adjustment to avoid frequent shutdowns; a timing-based anti-misjudgment filter circuit is used to filter and judge instantaneous current spikes and interference pulses, distinguishing between real overcurrent faults and electromagnetic interference false anomalies, and preventing false protection triggering; a fault self-locking shutdown circuit is used to identify severe short circuits and continuous overcurrent faults, triggering hardware self-locking to lock the drive output, preventing secondary damage caused by repeated start-stop cycles due to faults; a temperature-linked protection circuit is used to collect the temperature of power devices in real time, realizing overcurrent and high-temperature linked protection, and preventing high current temperature rise from burning out devices; a power-off energy storage memory circuit has a built-in supercapacitor energy storage unit, providing short-term power supply after the vehicle is powered off, and retaining overcurrent fault type, current peak value, fault timing and protection records, enabling accurate tracing of overcurrent faults.

[0007] Furthermore, one end of diode D1 is connected to one end of capacitor C1, one end of capacitor C3, and one end of diode D2; the other end of capacitor C1 is connected to the other end of capacitor C2; the other end of capacitor C3 is connected to one end of capacitor C4 and one end of resistor R1; the other end of diode D2 is connected to one end of resistor R2; and the other ends of capacitor C2, capacitor C4, resistor R1, and resistor R2 are all grounded.

[0008] Furthermore, one end of resistor R3 is connected to one end of diode D3, the other end of diode D3 is connected to the drain of transistor Q1, the gate of transistor Q1 is connected to one end of resistor R4 and one end of capacitor C5, and the other end of capacitor C5 and the source of transistor Q1 are both grounded. The high-precision current sampling circuit uses a low-temperature drift precision sampling resistor paired with a high-speed operational amplifier to simultaneously collect the total bus current and the three-phase independent phase current. The current sampling resolution is ≤0.1A, the sampling frequency is ≥20kHz, and it accurately captures instantaneous current fluctuations and slight overload conditions.

[0009] Furthermore, pins 2 and 1 of amplifier U1A are both connected to one end of resistor R7, and the other end of resistor R7 is connected to one end of capacitor C7. Pin 3 of amplifier U1A is connected to one end of capacitor C6 and one end of resistor R6. The other end of resistor R6 is connected to one end of resistor R5 and pin 2 of interface P1. Pin 1 of interface P1, the other end of resistor R5, the other end of capacitor C6, and the other end of capacitor C7 are all grounded. The high-precision current sampling circuit uses a low-temperature drift precision sampling resistor paired with a high-speed operational amplifier to simultaneously acquire the total bus current and the three-phase independent phase current. The current sampling resolution is ≤0.1A, and the sampling frequency is ≥20kHz, accurately capturing instantaneous current fluctuations and slight overload conditions.

[0010] Furthermore, pin 1 of integrated circuit U1 is connected to one end of resistor R10, the source of transistor Q2, and the drain of transistor Q3. The gate of transistor Q2 is connected to one end of resistor R8, and the gate of transistor Q3 is connected to one end of resistor R9. Pin 5 of integrated circuit U1 is connected to one end of resistor R11, and the other end of resistor R11 is connected to one end of capacitor C8. Pin 8 of integrated circuit U1 is connected to the other end of resistor R10. The other end of capacitor C8, pin 2 of integrated circuit U1, pin 3 of integrated circuit U1, and the source of transistor Q3 are all grounded. The hardware ultra-fast overcurrent detection circuit consists of a high-speed voltage comparator, a reference voltage threshold circuit, and a fast latch output unit. It requires no MCU operation intervention and has a response time ≤2μs. When a short-circuit instantaneous ultra-large overcurrent is detected, the three-phase drive output is directly cut off, realizing hardware ultra-fast hard protection.

[0011] Furthermore, the collector of transistor Q4 is connected to one end of resistor R14, one end of capacitor C9, and one end of resistor R12. The base of transistor Q4 is connected to the other end of resistor R14, one end of diode D4, one end of resistor R16, and the drain of transistor Q5. The other end of resistor R16 is connected to one end of capacitor C10. The gate of transistor Q5 is connected to one end of resistor R15. The other end of resistor R15, the other end of diode D4, the emitter of transistor Q4, and the other end of capacitor C9 are all connected to one end of resistor R13. The other end of resistor R13 is grounded. The software-graded current limiting control circuit sets three levels of overcurrent thresholds. Level 1 performs dynamic power reduction current limiting for minor overloads, Level 2 performs constant current clamping for moderate overcurrents, and Level 3 performs delayed shutdown in conjunction with hardware circuitry for severe overcurrents, achieving flexible protection while balancing riding smoothness and equipment safety.

[0012] Furthermore, one end of the inductor L1 is connected to one end of the capacitor C11. The timing-based anti-misjudgment filtering circuit adopts timing delay judgment and multiple sampling verification logic to automatically filter instantaneous interference spikes with a duration less than a preset threshold, and only judges continuous overcurrent as a real overcurrent fault, effectively avoiding protection false triggering caused by electromagnetic interference and road bumps.

[0013] Furthermore, one end of resistor R19 is connected to one end of resistor R18 and one end of resistor R17, and the other end of resistor R18 is connected to one end of capacitor C12. The other ends of capacitor C12 and resistor R19 are both grounded. The temperature linkage protection circuit has a thermal sampling unit set close to the power MOSFET and rectifier device to monitor the device temperature rise in real time under overcurrent conditions. When the current exceeds the standard and the temperature rise is too fast, the power reduction protection is activated in advance to avoid the controller being burned out by the superposition of high current and high temperature.

[0014] Furthermore, pin 2 of interface CN1 is connected to one end of resistor R20 and one end of resistor R21, pin 2 of interface CM2 is connected to one end of resistor R22 and one end of resistor R23, the other ends of resistors R21 and R23 are both connected to the collector of transistor Q5, the base of transistor Q5 is connected to one end of resistor R24 ​​and one end of resistor R25, and the other end of resistor R25 and the emitter of transistor Q5 are both grounded. The power-off energy storage memory circuit maintains continuous power supply for more than 200ms after the vehicle is powered off, and automatically stores data such as overcurrent peak current, fault occurrence time, overcurrent duration, and protection action type, providing data support for fault diagnosis and circuit optimization.

[0015] An overcurrent detection and protection circuit system for an electric vehicle intelligent controller includes an overcurrent detection and protection circuit system. The overcurrent detection and protection circuit system includes a current full-domain monitoring module, a hardware and software dual-path protection module, an overcurrent fault graded early warning module, a temperature linkage control module, a fault data tracing module, and a vehicle interaction module. The current full-domain monitoring module realizes synchronous real-time monitoring of bus current and three-phase current; The hardware and software dual-path protection module achieves dual protection: instantaneous short-circuit hardware high-speed protection and continuous overload software flexible current limiting. The overcurrent fault classification and early warning module outputs instrument prompts, audible and visual alarms, and pushes multi-level early warnings to the background for different levels of overcurrent faults. The temperature linkage control module realizes dual-parameter linkage protection of current and temperature to avoid the risk of high temperature and high current superposition. The fault data tracing module relies on the power failure memory unit to retain all overcurrent fault data and supports fault review. The vehicle interaction module is linked with the throttle, brakes, and instrument panel to achieve vehicle-wide linkage for overcurrent fault speed reduction, shutdown, and status display.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This circuit adopts a dual-path overcurrent protection architecture of hardware and software. The hardware circuit does not require MCU intervention and responds to short-circuit ultra-large current in microseconds, completely solving the problems of delayed response and easy device breakdown in traditional software protection. The software graded current limiting adapts to normal overload conditions, flexibly reduces power and clamps current, avoids abrupt shutdown, and greatly improves riding smoothness. 2. The system adopts synchronous full-area sampling of busbar and three-phase current. Compared with single busbar current sampling, it can accurately identify single-phase current abnormality, three-phase current imbalance, local leakage and hidden overcurrent faults, and provides full monitoring coverage without blind spots, resulting in higher fault identification accuracy. 3. The addition of a timing-based anti-misjudgment filter circuit and multiple sampling verification logic effectively filters out false current signals caused by electromagnetic interference, instantaneous spikes during start-up, and road bumps, preventing false protection triggers, solving the problems of frequent vehicle stalls and unexplained shutdowns, and significantly improving operational stability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overcurrent detection and protection circuit of the present invention; Figure 2 This is a circuit diagram of the main control MCU circuit of the present invention; Figure 3 This is a circuit diagram of the three-phase drive output circuit of the present invention; Figure 4 This is a circuit diagram of the power switch transistor circuit of the present invention; Figure 5 This is a circuit diagram of the high-precision current sampling circuit of the present invention; Figure 6 This is a circuit diagram of the hardware-based high-speed overcurrent detection circuit of the present invention; Figure 7 This is a circuit diagram of the software-graded current limiting and control circuit of the present invention; Figure 8 This is a circuit diagram of the timing misjudgment prevention filter circuit of the present invention; Figure 9 This is a circuit diagram of the temperature-linked protection circuit of the present invention; Figure 10 This is a circuit diagram of the power-off energy storage memory circuit of the present invention; Figure 11 This is a schematic diagram of the overcurrent detection and protection circuit system of the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1-11 This invention provides an overcurrent detection and protection circuit for an electric vehicle intelligent controller, including an overcurrent detection and protection circuit. The overcurrent detection and protection circuit includes a main control MCU circuit, a three-phase drive output circuit, a power switch tube circuit, a high-precision current sampling circuit, a hardware ultra-fast overcurrent detection circuit, a software graded current limiting and control circuit, a timing anti-misjudgment filter circuit, a fault self-locking shutdown circuit, a temperature linkage protection circuit, and a power failure energy storage memory circuit. The three-phase drive output circuit is connected to the signal terminal of the main control MCU circuit, and the hardware high-speed overcurrent detection circuit is electrically connected to the output terminal of the current sampling circuit. The main control MCU circuit contains an MCU chip, which is an STM32F103C8T6. Pins 47, 8, 23, and 35 of the MCU chip are all grounded. The three-phase drive output circuit includes diode D1, capacitors C1, C2, C3, and C4, resistors R1 and R2, and diode D2. The power switch circuit includes a resistor R4, a diode D3, a transistor Q1, a resistor R3, and a capacitor C5. The high-precision current sampling circuit includes interface P1, resistors R5, R6, and R7, capacitors C6 and C7, and amplifier U1A. Amplifier U1A is LM2904D and interface P1 is XH2.54-2P. The hardware-based high-speed overcurrent detection circuit includes an integrated circuit U1, resistors R8, R9, R10, and R11, transistors Q2 and Q3, and capacitor C8. The software-graded current limiting control circuit includes resistors R12, R13, R14, R15, and R16, capacitors C9 and C10, diode D4, transistor Q4, and transistor Q5. The timing misjudgment prevention filter circuit contains an inductor L1 and a capacitor C11; The temperature-linked protection circuit includes resistors R17, R18, and R19, and capacitor C12. The power-off energy storage memory circuit includes interface CN1, interface CN2, resistors R20, R21, R22, R23, R24, R25 and transistor Q5.

[0020] In operation, the main control MCU circuit serves as the core control unit, responsible for outputting PWM drive signals, acquiring real-time current conditions, running graded overcurrent protection algorithms, and executing current limiting and shutdown logic. The three-phase drive output circuit amplifies and isolates the drive signal, driving the downstream power switch circuit. The power switch circuit enables three-phase commutation and power output for the motor. The high-precision current sampling circuit synchronously acquires the total bus current and three-phase current, outputting accurate analog sampling signals. The hardware-based high-speed overcurrent detection circuit operates independently of the main control MCU, identifying instantaneous short circuits and massive overcurrent surges at the microsecond level, directly outputting hardware shutdown signals. The software-based graded current limiting and control circuit incorporates multiple overcurrent thresholds to address minor overloads, moderate overcurrents, and continuous overloads. The system features flexible current limiting and power reduction via software to prevent frequent shutdowns; a timing-based anti-misjudgment filter circuit to filter and judge instantaneous current spikes and interference pulses, distinguishing between genuine overcurrent faults and false electromagnetic interference anomalies, and preventing false protection triggering; a fault self-locking shutdown circuit to identify severe short circuits and persistent overcurrent faults, triggering hardware self-locking to prevent secondary damage caused by repeated start-stop cycles; a temperature-linked protection circuit to collect the temperature of power devices in real time, achieving overcurrent and high-temperature linked protection, preventing high current temperature rise from burning out devices; and a power-off energy storage memory circuit with a built-in supercapacitor energy storage unit to provide short-term power supply after the vehicle is powered off, retaining overcurrent fault types, current peak values, fault timing, and protection records, enabling accurate tracing of overcurrent faults.

[0021] One end of diode D1 is connected to one end of capacitor C1, one end of capacitor C3, and one end of diode D2. The other end of capacitor C1 is connected to the other end of capacitor C2. The other end of capacitor C3 is connected to one end of capacitor C4 and one end of resistor R1. The other end of diode D2 is connected to one end of resistor R2. The other ends of capacitor C2, capacitor C4, resistor R1, and resistor R2 are all grounded.

[0022] One end of resistor R3 is connected to one end of diode D3, the other end of diode D3 is connected to the drain of transistor Q1, the gate of transistor Q1 is connected to one end of resistor R4 and one end of capacitor C5, and the other end of capacitor C5 and the source of transistor Q1 are both grounded.

[0023] In use, the high-precision current sampling circuit uses a low-temperature drift precision sampling resistor paired with a high-speed operational amplifier to simultaneously collect the total bus current and the three independent phase currents. The current sampling resolution is ≤0.1A and the sampling frequency is ≥20kHz, accurately capturing instantaneous current fluctuations and slight overload conditions.

[0024] Pins 2 and 1 of amplifier U1A are both connected to one end of resistor R7. The other end of resistor R7 is connected to one end of capacitor C7. Pin 3 of amplifier U1A is connected to one end of capacitor C6 and one end of resistor R6. The other end of resistor R6 is connected to one end of resistor R5 and pin 2 of interface P1. Pin 1 of interface P1, the other end of resistor R5, the other end of capacitor C6, and the other end of capacitor C7 are all grounded.

[0025] In use, the high-precision current sampling circuit uses a low-temperature drift precision sampling resistor paired with a high-speed operational amplifier to simultaneously collect the total bus current and the three independent phase currents. The current sampling resolution is ≤0.1A and the sampling frequency is ≥20kHz, accurately capturing instantaneous current fluctuations and slight overload conditions.

[0026] One terminal of integrated circuit U1 is connected to one end of resistor R10, the source of transistor Q2, and the drain of transistor Q3. The gate of transistor Q2 is connected to one end of resistor R8, and the gate of transistor Q3 is connected to one end of resistor R9. One terminal of integrated circuit U1 is connected to one end of resistor R11. The other end of resistor R11 is connected to one end of capacitor C8. One terminal of integrated circuit U1 is connected to the other end of resistor R10. The other end of capacitor C8, one terminal of integrated circuit U1, one terminal of integrated circuit U1, and the source of transistor Q3 are all grounded.

[0027] In use, the hardware-based ultra-fast overcurrent detection circuit consists of a high-speed voltage comparator, a reference voltage threshold circuit, and a fast latching output unit. It requires no MCU operation intervention and has a response time of ≤2μs. When a short-circuit instantaneous ultra-large overcurrent is detected, it directly cuts off the three-phase drive output to achieve hardware-based ultra-fast hard protection.

[0028] The collector of transistor Q4 is connected to one end of resistor R14, one end of capacitor C9, and one end of resistor R12. The base of transistor Q4 is connected to the other end of resistor R14, one end of diode D4, one end of resistor R16, and the drain of transistor Q5. The other end of resistor R16 is connected to one end of capacitor C10. The gate of transistor Q5 is connected to one end of resistor R15. The other end of resistor R15, the other end of diode D4, the emitter of transistor Q4, and the other end of capacitor C9 are all connected to one end of resistor R13. The other end of resistor R13 is grounded.

[0029] When in use, the software-based graded current limiting and control circuit sets three levels of overcurrent thresholds. Level 1 for minor overloads implements dynamic power reduction and current limiting; Level 2 for moderate overcurrents implements constant current clamping; and Level 3 for severe overcurrents, in conjunction with hardware circuit delay shutdown, achieves flexible protection while balancing riding smoothness and equipment safety.

[0030] One end of inductor L1 is connected to one end of capacitor C11.

[0031] In use, the timing-based anti-misjudgment filter circuit adopts timing delay judgment and multiple sampling verification logic to automatically filter instantaneous interference spikes with a duration less than the preset threshold, and only judges continuous excessive current as a real overcurrent fault, effectively avoiding protection false triggering caused by electromagnetic interference and road bumps.

[0032] One end of resistor R19 is connected to one end of resistor R18 and one end of resistor R17. The other end of resistor R18 is connected to one end of capacitor C12. The other ends of capacitor C12 and resistor R19 are both grounded.

[0033] During use, the temperature linkage protection circuit is equipped with a thermal sampling unit closely attached to the power MOSFET and rectifier device. Under overcurrent conditions, it monitors the temperature rise of the device in real time. When the current exceeds the limit and the temperature rises too quickly, the power reduction protection is activated in advance to avoid the controller being burned out by the superposition of high current and high temperature.

[0034] Pin 2 of interface CN1 is connected to one end of resistor R20 and one end of resistor R21. Pin 2 of interface CM2 is connected to one end of resistor R22 and one end of resistor R23. The other ends of resistors R21 and R23 are both connected to the collector of transistor Q5. The base of transistor Q5 is connected to one end of resistor R24 ​​and one end of resistor R25. The other end of resistor R25 and the emitter of transistor Q5 are both grounded.

[0035] When in use, the power-off energy storage memory circuit maintains continuous power supply for more than 200ms after the vehicle is powered off, and automatically stores data such as overcurrent peak current, fault occurrence time, overcurrent duration, and protection action type, providing data support for fault diagnosis and circuit optimization.

[0036] An overcurrent detection and protection circuit system for an electric vehicle intelligent controller includes an overcurrent detection and protection circuit system. The overcurrent detection and protection circuit system includes a full-domain current monitoring module, a hardware and software dual-path protection module, an overcurrent fault graded early warning module, a temperature linkage control module, a fault data tracing module, and a vehicle interaction module. The current full-domain monitoring module enables synchronous real-time monitoring of bus current and three-phase current; The hardware and software dual-path protection module achieves dual protection: instantaneous short-circuit hardware high-speed protection and continuous overload software flexible current limiting. The overcurrent fault classification and early warning module outputs instrument prompts, audible and visual alarms, and pushes multi-level early warnings to the background for different levels of overcurrent faults. The temperature-linked control module enables dual-parameter protection based on current and temperature, avoiding the risk of combined high temperature and high current. The fault data tracing module relies on the power failure memory unit to retain all overcurrent fault data and supports fault review; The vehicle interaction module is linked with the throttle, brakes, and instrument panel to achieve vehicle-wide linkage for overcurrent fault speed reduction, shutdown, and status display.

[0037] In this invention, the main control MCU circuit is the core control unit, used to output PWM drive signals, acquire real-time current conditions, run graded overcurrent protection algorithms, and execute current limiting and shutdown logic; the three-phase drive output circuit amplifies and isolates the drive signal to drive the downstream power switch circuit; the power switch circuit is used to realize the three-phase commutation and power output of the motor; the high-precision current sampling circuit is used to synchronously acquire the total bus current and three-phase current, and output accurate analog sampling signals; the hardware ultra-fast overcurrent detection circuit operates independently of the main control MCU, used for microsecond-level identification. For instantaneous short circuits and massive overcurrent surges, a hardware shutdown signal is directly output. The software-based tiered current limiting and control circuit incorporates multiple overcurrent thresholds to implement flexible software current limiting and power reduction for minor, moderate, and sustained overload conditions, preventing frequent shutdowns. A timing-based anti-misjudgment filter circuit filters and judges instantaneous current spikes and interference pulses, distinguishing between genuine overcurrent faults and false electromagnetic interference anomalies to prevent false protection triggering. A fault-locking shutdown circuit identifies severe short circuits and sustained overcurrent surges, triggering a hardware-based self-locking drive output to prevent further shutdowns. Repeated start-stop cycles can cause secondary damage; the temperature-linked protection circuit collects the temperature of power devices in real time, realizing overcurrent and high-temperature linkage protection to prevent high current overheating from burning out devices; the power-off energy storage memory circuit has a built-in supercapacitor energy storage unit, providing short-term power supply after the vehicle is powered off, and retaining overcurrent fault types, current peaks, fault sequences, and protection records to achieve accurate tracing of overcurrent faults. After the equipment powers on and initializes and self-tests normally, the main control MCU outputs a PWM drive signal based on the throttle signal to drive the power circuit, ensuring smooth motor operation; high-precision current during operation... The sampling circuit collects current data in real time across the entire domain; the hardware-based high-speed overcurrent detection circuit constantly monitors extreme short-circuit faults; and the software-based graded current limiting circuit dynamically regulates overload conditions. The timing-based anti-misjudgment circuit filters out false interference signals, and the temperature linkage circuit synchronously monitors the temperature rise. In case of minor overload, the power is flexibly reduced; in case of moderate overcurrent, the current is clamped; and in case of severe short circuit, the hardware is rapidly shut down and self-locked. After a fault occurs, the power-off memory unit automatically retains the fault data, allowing maintenance personnel to quickly trace the source and repair it. The entire process achieves full-scenario, high-precision, high-reliability, and blind-spot-free overcurrent detection and intelligent protection for the electric vehicle controller.

[0038] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An overcurrent detection and protection circuit for an electric vehicle intelligent controller, comprising an overcurrent detection and protection circuit, Its features are: The overcurrent detection and protection circuit includes a main control MCU circuit, a three-phase drive output circuit, a power switch tube circuit, a high-precision current sampling circuit, a hardware ultra-fast overcurrent detection circuit, a software graded current limiting and control circuit, a timing anti-misjudgment filter circuit, a fault self-locking shutdown circuit, a temperature linkage protection circuit, and a power failure energy storage memory circuit. The three-phase drive output circuit is connected to the signal terminal of the main control MCU circuit, and the hardware high-speed overcurrent detection circuit is electrically connected to the output terminal of the current sampling circuit. The main control MCU circuit contains an MCU chip, which is an STM32F103C8T6. Pins 47, 8, 23, and 35 of the MCU chip are all grounded. The three-phase drive output circuit includes diode D1, capacitor C1, capacitor C2, capacitor C3, capacitor C4, resistor R1, resistor R2, and diode D2. The power switch circuit includes a resistor R4, a diode D3, a transistor Q1, a resistor R3, and a capacitor C5. The high-precision current sampling circuit includes an interface P1, resistors R5, R6, and R7, capacitors C6 and C7, and an amplifier U1A. The amplifier U1A is an LM2904D, and the interface P1 is an XH2.54-2P. The hardware-based high-speed overcurrent detection circuit includes an integrated circuit U1, resistors R8, R9, R10, and R11, transistors Q2 and Q3, and a capacitor C8. The software-defined hierarchical current limiting control circuit includes resistors R12, R13, R14, R15, and R16, capacitors C9 and C10, diode D4, transistor Q4, and transistor Q5. The timing misjudgment prevention filter circuit includes an inductor L1 and a capacitor C11. The temperature linkage protection circuit includes resistors R17, R18, and R19, and capacitor C12. The power-off energy storage memory circuit includes interface CN1, interface CN2, resistors R20, R21, R22, R23, R24, R25 and transistor Q5.

2. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: One end of diode D1 is connected to one end of capacitor C1, one end of capacitor C3 and one end of diode D2. The other end of capacitor C1 is connected to the other end of capacitor C2. The other end of capacitor C3 is connected to one end of capacitor C4 and one end of resistor R1. The other end of diode D2 is connected to one end of resistor R2. The other ends of capacitor C2, capacitor C4, resistor R1 and resistor R2 are all grounded.

3. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: One end of the resistor R3 is connected to one end of the diode D3, the other end of the diode D3 is connected to the drain of the transistor Q1, the gate of the transistor Q1 is connected to one end of the resistor R4 and one end of the capacitor C5, and the other end of the capacitor C5 and the source of the transistor Q1 are both grounded.

4. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: Pin 2 and pin 1 of amplifier U1A are both connected to one end of resistor R7. The other end of resistor R7 is connected to one end of capacitor C7. Pin 3 of amplifier U1A is connected to one end of capacitor C6 and one end of resistor R6. The other end of resistor R6 is connected to one end of resistor R5 and pin 2 of interface P1. Pin 1 of interface P1, the other end of resistor R5, the other end of capacitor C6, and the other end of capacitor C7 are all grounded.

5. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: One end of the integrated circuit U1 is connected to one end of resistor R10, the source of transistor Q2, and the drain of transistor Q3. The gate of transistor Q2 is connected to one end of resistor R8, and the gate of transistor Q3 is connected to one end of resistor R9. One end of the integrated circuit U1 is connected to one end of resistor R11, and the other end of resistor R11 is connected to one end of capacitor C8. One end of the integrated circuit U1 is connected to the other end of resistor R10. The other end of capacitor C8, one end of the integrated circuit U1, one end of the integrated circuit U1, and the source of transistor Q3 are all grounded.

6. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: The collector of transistor Q4 is connected to one end of resistor R14, one end of capacitor C9, and one end of resistor R12. The base of transistor Q4 is connected to the other end of resistor R14, one end of diode D4, one end of resistor R16, and the drain of transistor Q5. The other end of resistor R16 is connected to one end of capacitor C10. The gate of transistor Q5 is connected to one end of resistor R15. The other end of resistor R15, the other end of diode D4, the emitter of transistor Q4, and the other end of capacitor C9 are all connected to one end of resistor R13. The other end of resistor R13 is grounded.

7. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: One end of the inductor L1 is connected to one end of the capacitor C11.

8. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: One end of resistor R19 is connected to one end of resistor R18 and one end of resistor R17. The other end of resistor R18 is connected to one end of capacitor C12. The other end of capacitor C12 and the other end of resistor R19 are both grounded.

9. The overcurrent detection and protection circuit for an electric vehicle intelligent controller according to claim 1, characterized in that: Pin 2 of interface CN1 is connected to one end of resistor R20 and one end of resistor R21. Pin 2 of interface CM2 is connected to one end of resistor R22 and one end of resistor R23. The other ends of resistors R21 and R23 are both connected to the collector of transistor Q5. The base of transistor Q5 is connected to one end of resistor R24 ​​and one end of resistor R25. The other end of resistor R25 and the emitter of transistor Q5 are both grounded.

10. An overcurrent detection and protection circuit system for an electric vehicle intelligent controller according to any one of claims 1-9, comprising an overcurrent detection and protection circuit system, Its features are: The overcurrent detection and protection circuit system includes a current full-domain monitoring module, a hardware and software dual-path protection module, an overcurrent fault graded early warning module, a temperature linkage control module, a fault data tracing module, and a vehicle interaction module. The current full-domain monitoring module realizes synchronous real-time monitoring of bus current and three-phase current; The hardware and software dual-path protection module achieves dual protection: instantaneous short-circuit hardware high-speed protection and continuous overload software flexible current limiting. The overcurrent fault classification and early warning module outputs instrument prompts, audible and visual alarms, and pushes multi-level early warnings to the background for different levels of overcurrent faults. The temperature linkage control module realizes dual-parameter linkage protection of current and temperature to avoid the risk of high temperature and high current superposition. The fault data tracing module relies on the power failure memory unit to retain all overcurrent fault data and supports fault review. The vehicle interaction module is linked with the throttle, brakes, and instrument panel to achieve vehicle-wide linkage for overcurrent fault speed reduction, shutdown, and status display.

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