Three-phase current overcurrent detection circuit and method for motor controller

Abstract

The invention discloses a motor controller three-phase current overcurrent detection circuit and method, and the circuit comprises a current sampling module which is used for sampling a three-phase current value of a motor controller in real time, and transmitting the sampled three-phase current value to a three-phase overcurrent comparison module; the three-phase overcurrent comparison module is used for comparing the sampled three-phase current values with set overcurrent values, when any forward current is larger than a forward overcurrent threshold value or any reverse current is smaller than a reverse overcurrent threshold value, an overcurrent signal is output, and the set overcurrent values comprise the forward overcurrent threshold value and the reverse overcurrent threshold value; and the MCU control module is used for executing an over-current protection action according to the over-current signal, generating a threshold value adjusting signal and transmitting the threshold value adjusting signal to the over-current threshold value setting module. According to the circuit and the method, the safety performance of the motor controller during operation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicle motor control, and in particular to a three-phase current overcurrent detection circuit and method for a motor controller. Background Art

[0002] In the field of new energy vehicle motor controllers, three-phase current overcurrent protection is a core function to ensure system safety. Existing technologies mainly rely on two solutions:

[0003] A purely software-based detection solution uses an ADC to acquire three-phase currents, then executes a threshold comparison algorithm in the MCU, which triggers protection. This solution suffers from software processing delays, resulting in delayed overcurrent response and inability to accurately, reliably, and in real-time monitor three-phase overcurrent. Furthermore, if the software algorithm malfunctions, it cannot accurately determine three-phase overcurrent, leading to the risk of false alarms and, in extreme operating conditions, power transistor burnout.

[0004] Resistor voltage divider hardware solution: A discrete resistor network is used to generate a fixed threshold voltage, which then generates a real-time comparator output overcurrent signal. However, the resistor temperature coefficient (±200ppm / °C) causes threshold drift (±5% over the full temperature range of -40°C to 125°C), and online calibration is not possible, posing the risk of false alarms or missed alarms.

[0005] More critically, both solutions lack a threshold setting verification mechanism. When resistors age or software algorithms are abnormal, the system cannot detect detection failures. These shortcomings lead to irreconcilable contradictions in the existing solutions in terms of real-time performance, accuracy, and reliability. Summary of the Invention

[0006] In order to solve the technical problems existing in the background technology, the present invention proposes a three-phase current overcurrent detection circuit and method for a motor controller.

[0007] The present invention proposes a three-phase current overcurrent detection circuit for a motor controller, comprising:

[0008] The current sampling module is used to sample the three-phase current values ​​of the motor controller in real time and transmit the sampled three-phase current values ​​to the three-phase overcurrent comparison module;

[0009] The three-phase overcurrent comparison module is used to compare the sampled three-phase current values ​​with the set overcurrent values. When the forward current of any one item is greater than the forward overcurrent threshold or the reverse current of any one item is less than the reverse overcurrent threshold, an overcurrent signal is output. The set overcurrent value includes the forward overcurrent threshold and the reverse overcurrent threshold.

[0010] The MCU control module is used to perform overcurrent protection actions according to the overcurrent signal, and is also used to generate a threshold adjustment signal and transmit the threshold adjustment signal to the overcurrent threshold setting module;

[0011] The overcurrent threshold setting module is used to receive the threshold adjustment signal in real time and convert the threshold adjustment signal into a corresponding DC threshold voltage to obtain a set overcurrent value.

[0012] Preferably, the overcurrent threshold setting module specifically includes:

[0013] A forward overcurrent threshold unit is configured to receive a forward overcurrent threshold signal corresponding to the threshold adjustment signal in real time, and convert the forward overcurrent threshold signal into a corresponding forward overcurrent threshold voltage;

[0014] The reverse overcurrent threshold unit is used to receive the reverse overcurrent threshold signal corresponding to the threshold adjustment signal in real time, and convert the reverse overcurrent threshold signal into the corresponding reverse overcurrent threshold voltage.

[0015] Preferably, the forward overcurrent threshold unit includes a resistor R3, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a capacitor C3, a capacitor C4, and a capacitor C5, one end of the resistor R5 is electrically connected to one end of the resistor R6, the other end of the resistor R5 is connected to the power supply VDD1, the other end of the resistor R6 is electrically connected to one end of the capacitor C3, the other end of the capacitor C3 is grounded, one end of the capacitor C3 is electrically connected to one end of the resistor R7, the other end of the resistor R7 is electrically connected to one end of the capacitor C4, the other end of the capacitor C4 is grounded, one end of the capacitor C4 is electrically connected to one end of the resistor R3, one end of the capacitor C4 is electrically connected to one end of the capacitor C5, the other end of the capacitor C5 is grounded, the other end of the resistor R3 is electrically connected to one end of the capacitor C1, the other end of the capacitor C1 is grounded, and one end of the resistor R5 is connected to the forward overcurrent threshold signal.

[0016] Preferably, the reverse overcurrent threshold unit includes a resistor R10, a resistor R11, a resistor R12, a resistor R15, a capacitor C7, a capacitor C8, a capacitor C9, and a capacitor C10, one end of the resistor R15 is electrically connected to one end of the resistor R11, the other end of the resistor R15 is grounded, the other end of the resistor R11 is electrically connected to one end of the capacitor C8, the other end of the capacitor C8 is grounded, one end of the capacitor C8 is electrically connected to one end of the resistor R12, the other end of the resistor R12 is electrically connected to one end of the capacitor C9, the other end of the capacitor C9 is grounded, one end of the capacitor C9 is electrically connected to one end of the resistor R10, the other end of the resistor R10 is electrically connected to one end of the capacitor C7, the other end of the capacitor C7 is grounded, one end of the resistor R10 is electrically connected to one end of the capacitor C10, the other end of the capacitor C10 is grounded, and one end of the resistor R15 is connected to the reverse overcurrent threshold signal.

[0017] Preferably, the three-phase overcurrent comparison module specifically includes:

[0018] a reverse overcurrent threshold comparison unit, configured to compare the sampled three-phase current value with the reverse overcurrent threshold value at the same phase input, the reverse overcurrent threshold comparison unit comprising a first input resistor (R1, R2, R4) and a first group of operational amplifiers (U1A, U1B, U2A);

[0019] a forward overcurrent threshold comparison unit, configured to compare the sampled three-phase current value with the forward overcurrent threshold value at an inverting terminal input, the forward overcurrent threshold comparison unit comprising a second group of operational amplifiers (U1C, U1D, U2B) and a second input resistor (R13, R14, R16);

[0020] Among them, the output ends of the first group of operational amplifiers (U1A, U1B, U2A) and the second group of operational amplifiers (U1C, U1D, U2B) are connected in parallel to output overcurrent signals; the power supply voltage of the first group of operational amplifiers (U1A, U1B, U2A) and the second group of operational amplifiers (U1C, U1D, U2B) are both the controller system power supply VDD1.

[0021] Preferably, in the reverse overcurrent threshold comparison unit, the three-phase sampling current signals (IU_A, IV_A, IW_A) corresponding to the sampled three-phase current values ​​are respectively connected to the non-inverting input terminals of the first group of operational amplifiers (U1A, U1B, U2A) through the first input resistors (R1, R2, R4); the inverting input terminals of the first group of operational amplifiers (U1A, U1B, U2A) are connected to the threshold adjustment signal corresponding to the reverse overcurrent threshold.

[0022] Preferably, in the forward overcurrent threshold comparison unit, the three-phase sampling current signals corresponding to the sampled three-phase current values ​​are respectively connected to the inverting input terminals of the second group of operational amplifiers (U1C, U1D, U2B) through the second input resistors (R13, R14, R16); the non-inverting input terminals of the second group of operational amplifiers (U1C, U1D, U2B) are connected to the threshold adjustment signal corresponding to the forward overcurrent threshold.

[0023] Preferably, it also includes:

[0024] An alarm module is used to trigger an alarm in response to the overcurrent signal. The alarm module includes a current limiting resistor R8 and a light-emitting diode LED1. The output end of the overcurrent signal is electrically connected to the negative pole of the light-emitting diode LED1, the positive pole of the light-emitting diode LED1 is electrically connected to one end of the current limiting resistor R8, and the other end of the current limiting resistor R8 is connected to the power supply VDD2.

[0025] Preferably, it also includes:

[0026] The MCU control module is also used to retrieve the forward overcurrent threshold and reverse overcurrent threshold generated by the overcurrent threshold setting module in real time, and calculate the deviation between the retrieved forward overcurrent threshold and reverse overcurrent threshold and the target forward overcurrent threshold and reverse overcurrent threshold. When the deviation exceeds the preset range, the threshold adjustment is triggered.

[0027] The present invention proposes a method for detecting three-phase current overcurrent in a motor controller, which is applied to any one of the above-mentioned three-phase current overcurrent detection circuits in the motor controller. The method comprises:

[0028] Calculate the target overcurrent value based on the real-time operating conditions of the motor controller and generate a PWM signal with the corresponding duty cycle;

[0029] The PWM signal is converted into a DC threshold voltage through the overcurrent threshold setting module to obtain the set overcurrent value;

[0030] When receiving the overcurrent signal output by the three-phase overcurrent comparison module, the overcurrent protection action is executed according to the overcurrent signal, and the power tube drive is turned off within a preset time.

[0031] The present invention proposes a three-phase current overcurrent detection circuit and method for a motor controller. By monitoring the three-phase current in real time to see if it is overcurrent, the circuit promptly reports the overcurrent fault when the three-phase current is overcurrent, and makes timely adjustments, thereby protecting the motor controller from damage due to overcurrent. Flexible configuration of the overcurrent threshold facilitates timely adaptation to different operating conditions of the motor controller, expanding the scope of application of the overcurrent detection circuit. The overcurrent point recovery and verification function ensures that there will be no false alarms, no alarms, or unsuccessful overcurrent point settings due to deviations in the overcurrent point settings, thereby improving the safety performance of the motor controller during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the circuit architecture of a three-phase current overcurrent detection circuit for a motor controller proposed by the present invention;

[0033] Figure 2 This is a structural diagram of an embodiment of a three-phase overcurrent comparison module of a three-phase current overcurrent detection circuit of a motor controller proposed by the present invention;

[0034] Figure 3 This is a structural schematic diagram of an embodiment of an overcurrent threshold setting module of a three-phase current overcurrent detection circuit of a motor controller proposed by the present invention;

[0035] Figure 4 This is a schematic diagram of the working process of a three-phase current overcurrent detection method for a motor controller proposed by the present invention. DETAILED DESCRIPTION

[0036] Reference Figure 1-4The present invention proposes a three-phase current overcurrent detection circuit for a motor controller, comprising:

[0037] The current sampling module is used to sample the three-phase current values ​​of the motor controller in real time and transmit the sampled three-phase current values ​​to the three-phase overcurrent comparison module.

[0038] The three-phase overcurrent comparison module is used to compare the sampled three-phase current values ​​with the set overcurrent values. When the forward current of any item is greater than the forward overcurrent threshold or the reverse current of any item is less than the reverse overcurrent threshold, an overcurrent signal is output. The set overcurrent value includes the forward overcurrent threshold and the reverse overcurrent threshold.

[0039] In this embodiment, the three-phase overcurrent comparison module specifically includes:

[0040] A reverse overcurrent threshold comparison unit is used to compare the sampled three-phase current value with the reverse overcurrent threshold at the same phase input, and the reverse overcurrent threshold comparison unit includes a first input resistor (R1, R2, R4) and a first group of operational amplifiers (U1A, U1B, U2A);

[0041] A forward overcurrent threshold comparison unit is used to compare the sampled three-phase current value with the forward overcurrent threshold at the inverting terminal input. The forward overcurrent threshold comparison unit includes a second group of operational amplifiers (U1C, U1D, U2B) and a second input resistor (R13, R14, R16);

[0042] Among them, the output ends of the first group of operational amplifiers (U1A, U1B, U2A) and the second group of operational amplifiers (U1C, U1D, U2B) are connected in parallel to output overcurrent signals; the power supply voltage of the first group of operational amplifiers (U1A, U1B, U2A) and the second group of operational amplifiers (U1C, U1D, U2B) are both the controller system power supply VDD1.

[0043] Specifically, in the reverse overcurrent threshold comparison unit, the three-phase sampling current signals (IU_A, IV_A, IW_A) corresponding to the sampled three-phase current values ​​are respectively connected to the non-inverting input terminals of the first group of operational amplifiers (U1A, U1B, U2A) through the first input resistors (R1, R2, R4); the inverting input terminals of the first group of operational amplifiers (U1A, U1B, U2A) are connected to the threshold adjustment signal corresponding to the reverse overcurrent threshold.

[0044] Specifically, in the forward overcurrent threshold comparison unit, the three-phase sampling current signals corresponding to the sampled three-phase current values ​​are respectively connected to the inverting input terminals of the second group of operational amplifiers (U1C, U1D, U2B) through the second input resistors (R13, R14, R16); the non-inverting input terminals of the second group of operational amplifiers (U1C, U1D, U2B) are connected to the threshold adjustment signal corresponding to the forward overcurrent threshold.

[0045] In this embodiment, if Figure 2 As shown, the three-phase current sampled in real time is connected to the non-inverting inputs of operational amplifiers U1A, U1B, and U2A through first input resistors R1, R2, and R4, respectively. The reverse overcurrent threshold IUVW_N_REF is connected to the inverting inputs of operational amplifiers U1A, U1B, and U2A, respectively. The three-phase current sampled in real time is connected to the inverting inputs of operational amplifiers U1C, U1D, and U2B through second input resistors R13, R14, and R16, respectively. The forward overcurrent threshold IUVW_P_REF is connected to the non-inverting inputs of operational amplifiers U1C, U1D, and U2B, respectively. The outputs of operational amplifiers U1A, U1B, U2A, U1C, U1D, and U2B are connected together to output an overcurrent signal OC. The operational amplifiers are powered by the controller system architecture power supply VDD1. The alarm module consists of VDD2, current-limiting resistor R8, and LED1. When the value of any of the three-phase currents is higher than IUVW_P_REF or lower than IUVW_N_REF, the OC outputs a low level, the LED lights up, indicating the alarm status, and outputs the result to the MCU control module.

[0046] The MCU control module is used to perform overcurrent protection actions according to the overcurrent signal, and is also used to generate a threshold adjustment signal and transmit the threshold adjustment signal to the overcurrent threshold setting module.

[0047] In this embodiment, it also includes:

[0048] The MCU control module is also used to retrieve the forward overcurrent threshold and reverse overcurrent threshold generated by the overcurrent threshold setting module in real time, and calculate the deviation between the retrieved forward overcurrent threshold and reverse overcurrent threshold and the target forward overcurrent threshold and reverse overcurrent threshold. When the deviation exceeds the preset range, the threshold adjustment is triggered.

[0049] Specifically, the deviation between the actual voltage and the target voltage is calculated, and if the deviation exceeds ±2%, the PWM duty cycle is recalibrated.

[0050] The overcurrent threshold setting module is used to receive the threshold adjustment signal in real time and convert the threshold adjustment signal into a corresponding DC threshold voltage to obtain a set overcurrent value.

[0051] In this embodiment, the overcurrent threshold setting module specifically includes:

[0052] A forward overcurrent threshold unit is configured to receive a forward overcurrent threshold signal corresponding to the threshold adjustment signal in real time, and convert the forward overcurrent threshold signal into a corresponding forward overcurrent threshold voltage;

[0053] The reverse overcurrent threshold unit is used to receive the reverse overcurrent threshold signal corresponding to the threshold adjustment signal in real time, and convert the reverse overcurrent threshold signal into the corresponding reverse overcurrent threshold voltage.

[0054] Specifically, the forward overcurrent threshold unit includes a resistor R3, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a capacitor C3, a capacitor C4, and a capacitor C5. One end of the resistor R5 is electrically connected to one end of the resistor R6, and the other end of the resistor R5 is connected to the power supply VDD1. The other end of the resistor R6 is electrically connected to one end of the capacitor C3, and the other end of the capacitor C3 is grounded. One end of the capacitor C3 is electrically connected to one end of the resistor R7, and the other end of the resistor R7 is electrically connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded. One end of the capacitor C4 is electrically connected to one end of the resistor R3, one end of the capacitor C4 is electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is grounded. The other end of the resistor R3 is electrically connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded. One end of the resistor R5 is connected to the forward overcurrent threshold signal.

[0055] Specifically, the reverse overcurrent threshold unit includes a resistor R10, a resistor R11, a resistor R12, a resistor R15, a capacitor C7, a capacitor C8, a capacitor C9, and a capacitor C10. One end of the resistor R15 is electrically connected to one end of the resistor R11, and the other end of the resistor R15 is grounded. The other end of the resistor R11 is electrically connected to one end of the capacitor C8, and the other end of the capacitor C8 is grounded. One end of the capacitor C8 is electrically connected to one end of the resistor R12, and the other end of the resistor R12 is electrically connected to one end of the capacitor C9, and the other end of the capacitor C9 is grounded. One end of the capacitor C9 is electrically connected to one end of the resistor R10, and the other end of the resistor R10 is electrically connected to one end of the capacitor C7, and the other end of the capacitor C7 is grounded. One end of the resistor R10 is electrically connected to one end of the capacitor C10, and the other end of the capacitor C10 is grounded. One end of the resistor R15 is connected to the reverse overcurrent threshold signal.

[0056] In this embodiment, if Figure 1 and Figure 3 As shown in the figure, the MCU control module uses the inputs PWMOCREFP and PWMOCREFN to smoothly output the forward overcurrent threshold value IUVW_P_REF and the reverse overcurrent threshold value IUVW_N_REF through the overcurrent threshold setting module. The MCU control module sets the thresholds, adjusting the duty cycle of the waveforms input to MCU_PWM1 and MCU_PWM2 based on the real-time sampled current values. This allows the overcurrent point values ​​to be adjusted in real time according to the current operating conditions, enabling real-time and accurate detection of three-phase overcurrent. The overcurrent point settings are then accurately confirmed to the MCU via the outputs IUVW_P_REF_MCU and IUVW_N_REF_MCU, ensuring that no false alarms, no alarms, or unsuccessful overcurrent point settings occur.

[0057] In this embodiment, it also includes: an alarm module for triggering an alarm in response to an overcurrent signal, the alarm module includes a current limiting resistor R8 and a light-emitting diode LED1, the output end of the overcurrent signal is electrically connected to the negative pole of the light-emitting diode LED1, the positive pole of the light-emitting diode LED1 is electrically connected to one end of the current limiting resistor R8, and the other end of the current limiting resistor R8 is connected to the power supply VDD2.

[0058] In this embodiment, if Figure 1-3 As shown in the figure, when IU_A<IUVW_N_REF or IV_A<IUVW_N_REF or IW_A<IUVW_N_REF or IU_A>IUVW_P_REF or IV_A>IUVW_P_REF or IW_A>IUVW_P_REF, the OC output is low level L, the alarm LED1 lights up, and the three-phase current is overcurrent. When IU_A>IUVW_N_REF and IV_A>IUVW_N_REF and IW_A>IUVW_N_REF and IU_A<IUVW_P_REF and IV_A<IUVW_P_REF and IW_A<IUVW_P_REF, the OC output is high level H, the alarm LED1 does not light up, and the three-phase current is not overcurrent.

[0059] Reference Figure 1-4 The present invention proposes a motor controller three-phase current overcurrent detection method, which is applied to any of the motor controller three-phase current overcurrent detection circuits described above. The method comprises the following steps:

[0060] S1. Calculate the target overcurrent value based on the real-time working condition of the motor controller and generate a PWM signal with a corresponding duty cycle;

[0061] S2. Convert the PWM signal into a DC threshold voltage through the overcurrent threshold setting module to obtain the set overcurrent value;

[0062] S3. When receiving the overcurrent signal output by the three-phase overcurrent comparison module, the overcurrent protection action is executed according to the overcurrent signal, and the power tube drive is turned off within a preset time.

[0063] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A three-phase current overcurrent detection circuit for a motor controller, characterized in that: include: The current sampling module is used to sample the three-phase current values ​​of the motor controller in real time and transmit the sampled three-phase current values ​​to the three-phase overcurrent comparison module; The three-phase overcurrent comparison module is used to compare the sampled three-phase current values ​​with the set overcurrent values. When the forward current of any one item is greater than the forward overcurrent threshold or the reverse current of any one item is less than the reverse overcurrent threshold, an overcurrent signal is output. The set overcurrent value includes the forward overcurrent threshold and the reverse overcurrent threshold. The MCU control module is used to perform overcurrent protection actions according to the overcurrent signal, and is also used to generate a threshold adjustment signal and transmit the threshold adjustment signal to the overcurrent threshold setting module; The overcurrent threshold setting module is used to receive the threshold adjustment signal in real time and convert the threshold adjustment signal into a corresponding DC threshold voltage to obtain a set overcurrent value.

2. The motor controller three-phase current overcurrent detection circuit according to claim 1, characterized in that: The overcurrent threshold setting module specifically includes: A forward overcurrent threshold unit is configured to receive a forward overcurrent threshold signal corresponding to the threshold adjustment signal in real time, and convert the forward overcurrent threshold signal into a corresponding forward overcurrent threshold voltage; The reverse overcurrent threshold unit is used to receive the reverse overcurrent threshold signal corresponding to the threshold adjustment signal in real time, and convert the reverse overcurrent threshold signal into the corresponding reverse overcurrent threshold voltage.

3. The motor controller three-phase current overcurrent detection circuit according to claim 2, characterized in that: The forward overcurrent threshold unit includes a resistor R3, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a capacitor C3, a capacitor C4, and a capacitor C5. One end of the resistor R5 is electrically connected to one end of the resistor R6, and the other end of the resistor R5 is connected to the power supply VDD1. The other end of the resistor R6 is electrically connected to one end of the capacitor C3, and the other end of the capacitor C3 is grounded. One end of the capacitor C3 is electrically connected to one end of the resistor R7, and the other end of the resistor R7 is electrically connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded. One end of the capacitor C4 is electrically connected to one end of the resistor R3, one end of the capacitor C4 is electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is grounded. The other end of the resistor R3 is electrically connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded. One end of the resistor R5 is connected to the forward overcurrent threshold signal.

4. The motor controller three-phase current overcurrent detection circuit according to claim 2, characterized in that: The reverse overcurrent threshold unit includes a resistor R10, a resistor R11, a resistor R12, a resistor R15, a capacitor C7, a capacitor C8, a capacitor C9, and a capacitor C10. One end of the resistor R15 is electrically connected to one end of the resistor R11, and the other end of the resistor R15 is grounded. The other end of the resistor R11 is electrically connected to one end of the capacitor C8, and the other end of the capacitor C8 is grounded. One end of the capacitor C8 is electrically connected to one end of the resistor R12, and the other end of the resistor R12 is electrically connected to one end of the capacitor C9, and the other end of the capacitor C9 is grounded. One end of the capacitor C9 is electrically connected to one end of the resistor R10, and the other end of the resistor R10 is electrically connected to one end of the capacitor C7, and the other end of the capacitor C7 is grounded. One end of the resistor R10 is electrically connected to one end of the capacitor C10, and the other end of the capacitor C10 is grounded. One end of the resistor R15 is connected to the reverse overcurrent threshold signal.

5. The motor controller three-phase current overcurrent detection circuit according to claim 1, characterized in that: The three-phase overcurrent comparison module specifically includes: a reverse overcurrent threshold comparison unit, configured to compare the sampled three-phase current value with the reverse overcurrent threshold value at the same phase input, the reverse overcurrent threshold comparison unit comprising a first input resistor (R1, R2, R4) and a first group of operational amplifiers (U1A, U1B, U2A); a forward overcurrent threshold comparison unit, configured to compare the sampled three-phase current value with the forward overcurrent threshold value at an inverting terminal input, the forward overcurrent threshold comparison unit comprising a second group of operational amplifiers (U1C, U1D, U2B) and a second input resistor (R13, R14, R16); Among them, the output ends of the first group of operational amplifiers (U1A, U1B, U2A) and the second group of operational amplifiers (U1C, U1D, U2B) are connected in parallel to output overcurrent signals; the power supply voltage of the first group of operational amplifiers (U1A, U1B, U2A) and the second group of operational amplifiers (U1C, U1D, U2B) are both the controller system power supply VDD1.

6. The motor controller three-phase current overcurrent detection circuit according to claim 5, characterized in that: In the reverse overcurrent threshold comparison unit, the three-phase sampling current signals (IU_A, IV_A, IW_A) corresponding to the sampled three-phase current values ​​are respectively connected to the non-inverting input terminals of the first group of operational amplifiers (U1A, U1B, U2A) through the first input resistors (R1, R2, R4); the inverting input terminals of the first group of operational amplifiers (U1A, U1B, U2A) are connected to the threshold adjustment signals corresponding to the reverse overcurrent threshold.

7. The motor controller three-phase current overcurrent detection circuit according to claim 5, characterized in that: In the forward overcurrent threshold comparison unit, the three-phase sampling current signals corresponding to the sampled three-phase current values ​​are respectively connected to the inverting input terminals of the second group of operational amplifiers (U1C, U1D, U2B) through second input resistors (R13, R14, R16); the non-inverting input terminals of the second group of operational amplifiers (U1C, U1D, U2B) are connected to the threshold adjustment signals corresponding to the forward overcurrent threshold.

8. The motor controller three-phase current overcurrent detection circuit according to claim 1, characterized in that: Also includes: An alarm module is used to trigger an alarm in response to the overcurrent signal. The alarm module includes a current limiting resistor R8 and a light-emitting diode LED1. The output end of the overcurrent signal is electrically connected to the negative pole of the light-emitting diode LED1, the positive pole of the light-emitting diode LED1 is electrically connected to one end of the current limiting resistor R8, and the other end of the current limiting resistor R8 is connected to the power supply VDD2.

9. The motor controller three-phase current overcurrent detection circuit according to claim 1, characterized in that: Also includes: The MCU control module is also used to retrieve the forward overcurrent threshold and reverse overcurrent threshold generated by the overcurrent threshold setting module in real time, and calculate the deviation between the retrieved forward overcurrent threshold and reverse overcurrent threshold and the target forward overcurrent threshold and reverse overcurrent threshold. When the deviation exceeds the preset range, the threshold adjustment is triggered.

10. A method for detecting three-phase overcurrent in a motor controller, characterized in that: The method applied to the motor controller three-phase current overcurrent detection circuit according to any one of claims 1 to 9 includes: Calculate the target overcurrent value based on the real-time operating conditions of the motor controller and generate a PWM signal with the corresponding duty cycle; The PWM signal is converted into a DC threshold voltage through the overcurrent threshold setting module to obtain the set overcurrent value; When receiving the overcurrent signal output by the three-phase overcurrent comparison module, the overcurrent protection action is executed according to the overcurrent signal, and the power tube drive is turned off within a preset time.

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