Fault diagnosis method, system and equipment and computer readable storage medium

Abstract

The invention relates to the technical field of motor control, in particular to a fault diagnosis method, system and device and a computer readable storage medium, and the method comprises the steps: obtaining a current target value of a field weakening control process in a motor control system, comparing the current target value with a preset threshold value, and achieving the early monitoring of the whole-link fault of an FOC system; when it is detected that the current target value is smaller than the preset current threshold value, counting accumulation is carried out to obtain a count value, the count value is compared with a preset counter over-limit value, and anti-interference accurate judgment is achieved; and when the count value is greater than the preset counter over-limit value, determining that the motor control system has a fault, thereby realizing timely identification and response to a real fault, ensuring that only a continuously existing systematic fault is judged, breaking through the limitation that only a single-link fault can be monitored by depending on a special sensor traditionally, and improving the reliability of the motor control system. And the operation safety and stability of the motor control system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, and in particular to a fault diagnosis method, system, device and computer readable storage medium. BACKGROUND

[0002] The FOC (Field-Oriented Control) system of a permanent magnet synchronous motor is a core control unit in the fields of automobile driving and industrial frequency converters, and its running stability directly determines the safety and efficiency of the equipment, so the fault diagnosis function becomes a key component of the FOC system.

[0003] The current fault diagnosis processing mode is: for the faults of different links of the FOC system, corresponding additional special sensors and matching sampling circuits are configured - for example, a redundant current sensor needs to be installed to detect the fault of a current sensor, a spare encoder needs to be installed to diagnose the abnormality of a position sensor, and an independent sampling module needs to be additionally set to monitor the sampling failure of a bus voltage.

[0004] This mode is limited by the number of sensor configurations and cannot cover the links in the FOC system without special sensors (such as PWM drive chip failure and software signal processing module failure), is prone to fault misdiagnosis, and leads to abnormal operation of the equipment and even causes safety accidents, so it is urgent to break through the limitations of traditional dependence on additional special sensors and realize full-link fault monitoring of the FOC system, which is the goal to be achieved in the current FOC system fault diagnosis field.

[0005] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0006] The main purpose of the present application is to provide a fault diagnosis method, system, device and storage medium, which aims to break through the limitations of traditional dependence on additional special sensors and realize full-link fault monitoring of the FOC system.

[0007] To achieve the above purpose, the present application provides a fault diagnosis method, which comprises: Obtaining a current target value of a field weakening control process in a motor control system, and comparing the current target value with a preset threshold value; When it is detected that the current target value is less than the preset current threshold value, counting is accumulated to obtain a count value, and the count value is compared with a preset counter overflow value; When the count value is greater than the preset counter overflow value, it is determined that the motor control system has a fault.

[0008] In addition, to achieve the above purpose, the present application also provides a motor control system, which comprises a controller, and the controller comprises: The acquisition module is configured to acquire a current target value of a field weakening control process in the motor control system, and compare the current target value with a preset threshold value. The comparison module is configured to, when detecting that the current target value is less than the preset current threshold value, accumulate a count value, and compare the count value with a preset counter over-limit value. The determination module is configured to, when the count value is greater than the preset counter over-limit value, determine that the motor control system has a fault.

[0009] The various functional modules of the fault diagnosis device according to the present application implement the steps of the fault diagnosis method according to the present application when in operation.

[0010] In addition, to achieve the above-mentioned purpose, the present application also provides a fault diagnosis device, which comprises a memory, a processor, and a fault diagnosis program stored in the memory and executable on the processor, and the steps of the fault diagnosis method according to the present application are implemented when the fault diagnosis program is executed by the processor.

[0011] In addition, to achieve the above-mentioned purpose, the present application also provides a storage medium, which is a computer-readable storage medium, and a fault diagnosis program is stored on the computer-readable storage medium, and the steps of the fault diagnosis method according to the present application are implemented when the fault diagnosis program is executed by a processor.

[0012] The present application provides a fault diagnosis method, and the present application realizes early monitoring of full-link faults of a FOC system by acquiring a current target value of a field weakening control process in a motor control system and comparing the current target value with a preset threshold value; realizes accurate and anti-interference determination by accumulating a count value when detecting that the current target value is less than the preset current threshold value and comparing the count value with a preset counter over-limit value; and determines that the motor control system has a fault when the count value is greater than the preset counter over-limit value, thereby realizing timely identification and response to real faults, ensuring that only a persistent systematic fault is determined, breaking through the limitation of traditional methods that rely on special sensors to monitor only single-link faults, and improving the operational safety and stability of the motor control system. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a flowchart of the first embodiment of the fault diagnosis method according to the present application; Figure 2 is a logic diagram of field weakening over-limit determination according to the present application; Figure 3 is a structural diagram of a controller according to the embodiment of the present application; Figure 4 is a control flowchart of a permanent magnet synchronous motor FOC system according to the present application; Figure 5 is a structural schematic diagram of a fault diagnosis device involved in the embodiment scheme of the present application.

[0014] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings.

[0015] Explanation of reference numerals: 10, current controller; 20, first converter; 30, inverter; 40, position sensor; 50, second converter. DETAILED DESCRIPTION

[0016] The embodiment of the present application provides a fault diagnosis method, referring to Figure 1 , as shown in Figure 1 is a flowchart of the first embodiment of the fault diagnosis method of the present application.

[0017] The exemplary embodiments will be described in detail below, and examples are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0018] Permanent magnet synchronous motor has become the core power unit in the field of electric vehicles and other fields due to its high efficiency and wide range of weak magnetic speed regulation, and the reliability of its fault diagnosis is directly related to the safety of vehicle operation.

[0019] The current mainstream fault diagnosis technology has prominent limitations: on the one hand, it relies too much on sensor redundancy, such as the need for additional redundant encoders to detect the failure of the rotary transformer, and the need to rely on backup detection channels to diagnose current sensor faults, which directly increases the cost of hardware and signal processing; on the other hand, there is obvious delay in dynamic response, making it difficult to capture faults in time; more importantly, in the high-speed running scenario of deep weak magnetism, voltage saturation easily leads to loss of control of the current loop, and position error is easily masked by weak magnetic current compensation, making it difficult to effectively detect faults such as rotary transformer failure, forming a diagnostic blind area.

[0020] These problems seriously restrict the reliable application of permanent magnet synchronous motors in key working conditions such as high speed, and it is urgent to break through existing technologies to achieve low-cost and high-reliability fault diagnosis under all working conditions. The present application provides a fault diagnosis method, system, device and storage medium.

[0021] It should be noted that the execution subject of the present embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, a database system, etc., or a device capable of realizing the above functions, such as a fault diagnosis device. The present embodiment and each of the following embodiments will be described below with the fault diagnosis device as an example.

[0022] The fault diagnosis method of the present application comprises the following implementation steps S10 to S30.

[0023] Step S10: Obtain the current target value of the field weakening control process in the motor control system, and compare the current target value with a preset threshold value; Optionally, in this embodiment, as an example, the application scenario can be a permanent magnet synchronous motor FOC drive system of an electric vehicle. In this scenario, the motor needs to frequently operate in low-speed high-torque (such as starting and climbing) and high-speed field weakening (such as high-speed cruising) conditions, and the requirements for "low cost", "full working condition coverage" and "real-time" of fault diagnosis are prominent. At low speed, it is necessary to avoid torque out of control caused by current sensor failure. At high speed, it is necessary to prevent voltage overrun risks caused by position feedback error of the rotary transformer and abnormality of the bus voltage sampling. The traditional diagnosis scheme relying on redundant sensors will significantly increase the cost of the vehicle controller, and in the deep field weakening condition, the diagnosis blind area is easily formed due to voltage saturation. The technical scheme can be directly adapted to the FOC control logic of the scenario, without additional sensors. By monitoring the IdTgt overrun state of the FOC field weakening control loop, the core faults such as bus under-voltage, drive open circuit, current sensor failure, and position error in the field weakening area can be covered. At the same time, after fault determination, the active short-circuit protection special for the automobile scene is triggered, so that the vehicle can still be controlled to slow down when the FOC system fails.

[0024] Optionally, FOC is a motor control strategy that achieves independent control of the magnetic field and torque by decomposing the motor stator current into the d-q synchronous rotating coordinate system; IdTgt (d-axis current target value) is the core instruction output by the field weakening control link, used to guide the adjustment of the d-axis current; Usref (maximum allowable voltage utilization rate): a pre-set voltage safety threshold, limiting the maximum available proportion of inverter output voltage (for example, it can be set to 95% of the bus voltage, to avoid voltage overrun and damage hardware); Us (actual voltage utilization rate): reflects the proportion of voltage resources currently consumed by the motor, calculated from the voltage components in the d-q coordinate system; ud (d-axis voltage component): the d-axis voltage instruction output by the current loop in the FOC system, used to control the d-axis current; uq (q-axis voltage component): the q-axis voltage instruction output by the current loop in the FOC system, directly affecting the motor torque output; PI controller (Proportional-Integral Controller): a control unit that achieves precise adjustment of the deviation by real-time response of the proportional link and elimination of steady-state error by the integral link; Field weakening table: a table storing the mapping relationship between "motor speed - basic field weakening current", providing a reference current for field weakening control at different speeds; Idref (basic field weakening current value): the field weakening current reference matched with the current running speed of the motor, obtained from the field weakening table, to ensure the initial stability of field weakening control; IdMin (d-axis current preset threshold): the negative safety limit of the d-axis current, used to determine whether IdTgt is abnormal, the value needs to be determined in combination with the motor magnetic steel demagnetization resistance and rated current (for example, it can be set to -150A for a certain type of motor, or adjusted as needed); Field weakening control: a control mechanism that releases voltage space by adjusting the d-axis current to weaken the permanent magnet magnetic field and reduce the back electromotive force when the motor runs at high speed in the FOC system.

[0025] Optionally, in the FOC motor control system, the d-axis current target value IdTgt of the field weakening control process is generated by relying on the existing field weakening control logic of the system: the actual voltage utilization rate Us is obtained by combining the voltage components in the d-q coordinate system in the FOC system, and the voltage state deviation formed by the pre-set maximum allowable voltage utilization rate Usref is processed by the deviation adjustment unit, and then the basic field weakening current reference adapted to the current motor speed is fused, to finally generate IdTgt for field weakening control; This process does not require additional hardware or complex control modules, directly reuses the existing field weakening control related links of FOC, can adapt to different speed and bus voltage scenarios, and reduces system cost.

[0026] Optionally, after generating IdTgt, it is compared with a preset negative d-axis current safety threshold IdMin, and whether the field weakening control state has an abnormal risk is determined according to the comparison result: if IdTgt is lower than IdMin, it indicates that the d-axis current has excessive demagnetization in the field weakening control process, prompting that the system may have a fault; if IdTgt is not lower than IdMin, it is determined that the field weakening control is currently in a normal state; since any link fault in the FOC system, such as bus voltage abnormality, current sensing failure, and position feedback error, will be conducted to IdTgt through voltage state deviation, causing IdTgt to be abnormally low, the comparison process can capture the FOC full-link fault precursor in time, realize early fault monitoring, and avoid the missed diagnosis problem caused by the limited coverage of the traditional scheme relying on special sensors.

[0027] Step S20: When it is detected that the current target value is less than the preset current threshold, a count value is obtained by counting accumulation, and the count value is compared with a preset counter over-limit value; Optionally, the count value is CNT (Count), which is the number of control periods or the time length when the current target value is less than the preset current threshold; the preset counter over-limit value (TIMOUT_VAL (Timeout Value)) is a preset counter determination threshold, which is used to distinguish between transient abnormality and continuous fault of IdTgt, and the value is determined based on the maximum transient interference time length of the system, for example, 5 FOC control periods, each period being 100 μs.

[0028] Optionally, in the field weakening control process of the permanent magnet synchronous motor FOC system, after the system generates IdTgt (d-axis current target value), IdTgt is compared with a preset current threshold IdMin (such as -150 A); if it is detected that IdTgt < IdMin, it indicates that the d-axis current target value has exceeded the negative safety range at this time, and the motor has an excessive demagnetization risk, and the system will immediately trigger the counter to start accumulation - every time a FOC control period (such as 100 μs) is passed, the count value CNT increases by 1; this counting accumulation process can effectively filter transient interference, such as temporary abnormality (such as lasting only 1 control period) of IdTgt caused by electromagnetic radiation and short-time load fluctuation during motor operation, at this time, CNT is only accumulated to 1, and will not reach the subsequent over-limit value, avoiding the mistake of judging the transient interference as a fault, and improving the anti-interference ability of fault determination.

[0029] Optionally, when the counter accumulates CNT, the system compares CNT with a pre-designed counter over-limit value TIMOUT_VAL (such as 5 control periods): if CNT≤TIMOUT_VAL, it means that the abnormal state of IdTgt lasts for a short time, and it is determined to be transient interference, without triggering a fault alarm; if CNT>TIMOUT_VAL, it means that IdTgt is continuously in an abnormal state of excessive demagnetization, at which time it is determined that the FOC system has a field weakening over-limit fault, and protection measures (such as reducing the motor speed and limiting the torque output) need to be started. Since the setting of TIMOUT_VAL fully covers the maximum transient interference time that the system may have (such as electromagnetic interference in an industrial scene usually not exceeding 3 control periods), this comparison process ensures that only a real and continuous fault is determined, avoiding the misjudgment problem of the traditional single threshold determination, further improving the reliability of fault diagnosis, ensuring the stable operation of the motor in critical working conditions such as high-speed field weakening, and especially suitable for scenes such as electric vehicles and industrial frequency converters that have high requirements for operation safety.

[0030] Step S30: When the count value is greater than the pre-designed counter over-limit value, it is determined that the motor control system has a fault.

[0031] Optionally, in the permanent magnet synchronous motor FOC system, the fault refers to the FOC system field weakening over-limit fault, which is caused by abnormality of system hardware (such as bus under-voltage, current sensor failure) or software (such as current loop control divergence) link, resulting in a fault state in which IdTgt continuously exceeds the safe range.

[0032] Optionally, when the accumulated count value CNT is greater than the pre-designed counter over-limit value TIMOUT_VAL (such as 5 FOC control periods), the system determines that the motor control system has a field weakening over-limit fault. The core basis of this determination logic is that the setting of TIMOUT_VAL has fully covered the maximum transient interference time that may occur in actual system operation (such as electromagnetic interference and short-term load fluctuation in an industrial scene usually not exceeding 3 control periods), and if CNT exceeds this value, it means that the abnormal state of IdTgt (d-axis current target value) is not transient interference, but is caused by continuous fault of the FOC system—for example, serious bus under-voltage will cause the voltage utilization rate Us to continuously exceed the allowed value Usref, and the field weakening control loop will continuously increase the negative amplitude of IdTgt, resulting in IdTgt continuously less than IdMin (such as -150A), and then CNT continuously accumulates and exceeds TIMOUT_VAL; for example, current sensor failure will distort the current feedback and cause the current loop control to diverge, which will also cause IdTgt to continuously abnormally, and eventually CNT will exceed the limit.

[0033] Optionally, after determining the fault, the system can start protective measures (such as reducing motor speed, limiting torque output, or cutting off unnecessary loads) in time to avoid further expansion of the fault; this determination process ensures that only real and continuous systemic faults are identified, completely avoiding the problem of traditional single threshold determination that can easily misjudge transient interference as a fault, improving the accuracy of fault diagnosis; at the same time, by clearly defining the criteria for determining the existence of a fault, the system provides a reliable basis for subsequent protection mechanisms, effectively ensuring the safe operation of the motor in critical operating conditions such as high-speed field weakening, especially in scenarios such as electric vehicles and industrial frequency converters that require high system reliability, further improving the overall stability of the motor control system.

[0034] Optionally, in a permanent magnet synchronous motor FOC system, when the system detects that IdTgt is less than IdMin (such as -150A), a counter is started to accumulate to obtain a count value CNT; then CNT is compared with a pre-designed counter overrun value TIMOUT_VAL (such as 5 FOC control periods); if it is determined that CNT is less than or equal to TIMOUT_VAL, the system determines that the abnormal state of IdTgt is transient interference, and does not trigger a fault alarm or protective measures; by comparing CNT with TIMOUT_VAL, only continuous abnormality triggers protection, which not only ensures the sensitivity of the system to real faults, but also ensures the stability of normal operation.

[0035] Optionally, the setting of TIMOUT_VAL has fully covered the maximum transient interference duration that may occur in the actual operation of the system (such as electromagnetic interference in industrial scenarios, short-term load fluctuations in electric vehicles usually only last for 1-3 FOC control periods, i.e. 100μs-300μs); if CNT≤TIMOUT_VAL, it means that the abnormality of IdTgt does not exceed the interference tolerance range, and is not caused by continuous failure of the FOC system hardware (such as current sensor, bus voltage sampling circuit) or software (such as current loop control algorithm). For example, when an electric vehicle frequently starts and stops on a congested road, short-term load fluctuations may cause IdTgt to temporarily drop to -160A (less than IdMin-150A), but this abnormality only lasts for 2 FOC control periods (200μs), and CNT accumulates to 2, which is less than TIMOUT_VAL 5, so the system determines it as transient interference and does not trigger a fault response, thereby effectively avoiding the problem of "misjudging transient interference as a fault" - traditional single threshold determination (only detecting whether IdTgt is less than IdMin) is easy to trigger unnecessary protective measures (such as speed reduction, torque interruption) due to transient fluctuations, which can cause continuous interruption of motor operation and affect user experience (such as electric vehicle driving jerk).

[0036] In this embodiment, the current target value of the field weakening control process in the motor control system is obtained, and the current target value is compared with the preset threshold value, so as to realize early monitoring of the full-link fault of the FOC system; when it is detected that the current target value is less than the preset current threshold value, the counting value is obtained by counting accumulation, and the counting value is compared with the pre-designed counter overrun value, so as to realize accurate judgment of anti-interference; when the counting value is greater than the pre-designed counter overrun value, it is determined that the motor control system has a fault, and then timely identification and response to the real fault are realized, so as to ensure that only the persistent systematic fault is determined, break through the limitation of traditional dependence on special sensors that can only monitor single-link faults, and improve the operation safety and stability of the motor control system.

[0037] Further, based on the above, the second embodiment of the fault diagnosis method of the present application is proposed. In some feasible embodiments, the above step S10 further includes the following implementation steps B201-B203.

[0038] Step B201: Obtain the actual voltage utilization rate of the field weakening control process in the motor control system and the preset voltage safety threshold value, and obtain the first deviation value by subtracting the preset voltage safety threshold value from the actual voltage utilization rate; Step B202: Proportionally integrate the first deviation value to obtain the field weakening current adjustment amount; Step B203: Obtain the preset basic field weakening current value, add the field weakening current adjustment amount to the preset basic field weakening current value to generate the current target value.

[0039] Optionally, the actual voltage utilization rate Us is a parameter obtained by reflecting the voltage vector amplitude calculation logic based on the voltage component in the d-q synchronous rotating coordinate system in the permanent magnet synchronous motor FOC system, and is used to represent the actual proportion of the current output voltage of the inverter to the bus voltage; the preset voltage safety threshold value Usref is a preset maximum available proportion of the inverter output voltage, and the value is determined based on the bus voltage and the hardware withstand voltage characteristic, and in this embodiment, it is set to 95% of the bus voltage, such as (300V / √3)*95% voltage amplitude, which is used to limit the voltage output to avoid hardware overrun damage); the first deviation value ΔU is the difference between Usref and Us, which is used to reflect the deviation degree of the current voltage state from the safety threshold value, and provides a quantitative basis for the field weakening current adjustment; the proportional integral PI is a control algorithm, which realizes accurate adjustment of the deviation by real-time response of the proportional link and elimination of the steady-state error of the integral link; the field weakening current adjustment amount ΔI is obtained by processing the first deviation value. d, the d-axis current correction value obtained after PI adjustment, used to dynamically adjust the field weakening current according to the voltage deviation, balance the voltage utilization rate and the field weakening demand; the preset basic field weakening current value Idref, stored in the field weakening table (a table recording the mapping relationship of "motor speed-basic field weakening current"), the field weakening current reference value determined based on the current motor speed, providing an initial current reference for field weakening control at different speeds, for example, when the motor speed is 1000 rpm, Idref can be set to -50 A); the current target value IdTgt, the d-axis current instruction finally output by the field weakening control link, generated by superimposing the field weakening current adjustment amount and the basic field weakening current value, used to guide the FOC system to adjust the d-axis current and control the weakening degree of the motor magnetic field; Weak Magnetic Control: a control mechanism for maintaining stable high-speed operation by adjusting the d-axis current to weaken the permanent magnet magnetic field and reduce the back electromotive force to release voltage space in the FOC system when the motor runs at high speed; non-transitory computer readable storage medium: used to store software modules related to the field weakening control of the application, such as field weakening table data and PI control parameters, which can specifically use ROM, EEPROM or external solid state disk to support the operation unit (such as MCU) of the FOC controller to read and execute the control logic.

[0040] Optionally, in the field weakening control process of the permanent magnet synchronous motor FOC system, first, the actual voltage utilization rate Us and the preset voltage safety threshold Usref need to be obtained: Us is obtained by the calculation logic representing the voltage vector amplitude based on the d-axis voltage component ud and the q-axis voltage component uq output by the FOC system current loop, which can reflect the consumption state of the current voltage resource in real time; Usref is preset at 95% of the bus voltage (such as (300 / sqrt(3))*95% of the voltage amplitude), to ensure that the voltage output is always within the hardware safety range; the difference between the two is the first deviation ΔU, which accurately captures the voltage deviation by directly associating the voltage safety threshold with the actual running state - for example, when the motor runs at high speed (such as the speed rises to 3000 rpm), the back electromotive force rises, which will cause Us to exceed Usref, at this time, ΔU presents a negative deviation, which provides a clear quantitative signal for subsequent field weakening current adjustment, avoiding the risk of voltage overrun caused by the traditional field weakening control which only relies on the speed and lacks real-time voltage feedback, and improving the timeliness of voltage control.

[0041] Then, the first deviation ΔU is sent to the PI controller for proportional and integral adjustment to obtain the field weakening current adjustment amount ΔI dThe proportional part of the PI controller outputs a corresponding adjustment component in real time according to the deviation of ΔU (for example, when the negative deviation of ΔU increases, the proportional component also increases to speed up the adjustment); the integral part accumulates historical deviations and gradually eliminates steady-state errors (for example, when there is a small continuous deviation in ΔU, the integral component continuously corrects until the deviation approaches zero), so that this adjustment mode considers both dynamic response speed and steady-state control accuracy - when ΔU suddenly changes, the proportional part responds quickly to suppress the voltage from deviating further from the safety threshold; when ΔU is stable in a small deviation range, the integral part ensures that Us is eventually stable near Usref, avoiding voltage fluctuations caused by insufficient or excessive adjustment, and ensuring the stability of the field weakening control. Finally, the preset basic field weakening current value Idref (such as -60A when the speed is 3000 rpm) that matches the current speed of the motor is obtained from the field weakening table, and it is compared with the field weakening current adjustment amount ΔI d to generate the current target value IdTgt; the introduction of Idref provides a reasonable initial reference for field weakening control at different speeds: at low speed, the absolute value of Idref is small, avoiding excessive demagnetization of the motor magnetic steel; at high speed, the absolute value of Idref increases to meet the demand for weakening the magnetic field and releasing voltage space. The dynamic correction of ΔI d allows Idref to adapt to changes in voltage deviation in real time - for example, when Us exceeds Usref, ΔI d is negative, which increases the absolute value of IdTgt, further weakens the magnetic field to reduce the back electromotive force, and thus pulls Us back to the safe range, achieving dynamic balance between voltage and magnetic field.

[0042] In this embodiment, the entire process does not require additional voltage sensors or complex control hardware, but relies on the existing voltage component calculation, PI adjustment and field weakening table resources of the FOC system, effectively reducing the hardware cost of the system; at the same time, the generation of IdTgt combines the basic reference corresponding to the speed and the real-time adjustment of the voltage deviation, which can adapt to the field weakening demand of the motor in the full speed range, quickly respond to voltage abnormalities, ensure the stable operation of the FOC system in the high-speed field weakening working condition (such as high-speed cruising of electric vehicles), avoid faults caused by voltage out-of-limit or excessive demagnetization of the magnetic field, and improve the reliability and scene adaptability of the motor control system. The field weakening control logic of the present application is implemented by a software module stored in a non-transitory computer readable storage medium, which can be integrated into the MCU (Microcontroller Unit) of the FOC controller (such as a vehicle-mounted motor controller) for execution, further improving the engineering application value of the scheme.

[0043] Further, based on the above content, in some feasible embodiments, the above step A201 further includes the following implementation steps C201-C202 before step A201.

[0044] Step C201: Obtain the d-axis voltage component and the q-axis voltage component of the motor control system; Step C202: Input the d-axis voltage component and the q-axis voltage component into a preset voltage utilization rate calculation formula to obtain an actual voltage utilization rate; Optionally, the d-axis voltage component: ud, in the FOC system of the permanent magnet synchronous motor, is a d-axis voltage instruction output by a current loop, used to adjust the d-axis current to control the weakening or strengthening of the motor magnetic field, directly affecting the flux linkage state of the motor, such as the weakening demand of the magnetic field, which needs to be dynamically adjusted; the q-axis voltage component: uq, in the FOC system of the permanent magnet synchronous motor, is a q-axis voltage instruction output by a current loop, used to adjust the q-axis current to control the motor output torque, the q-axis current is linearly related to the torque, and the size of uq directly determines the torque output capability, such as the starting of an electric vehicle, which needs to increase uq to increase the torque; the preset voltage utilization rate calculation formula: the voltage vector amplitude operation logic pre-stored in the FOC controller, used to convert ud and uq in the d-q coordinate system into a parameter representing the overall voltage consumption state, and the operation logic is designed based on the mathematical characteristics of the voltage vector in the synchronous rotating coordinate system; the actual voltage utilization rate: Us, a parameter calculated by the preset formula, used to represent the actual proportion of the current output voltage of the inverter to the bus voltage, reflecting the voltage resource consumption state of the motor during operation, such as Us being too high, indicating that the voltage is close to the bus limit value, and the field weakening control needs to be started; FOC: field oriented control, by decomposing the motor stator current into the d-q synchronous rotating coordinate system, realizing the motor control strategy of independent control of magnetic field and torque; current loop: a closed-loop regulation unit in the FOC system, receiving d-axis and q-axis current instructions and feedback currents, outputting ud and uq through PI (Proportional-Integral) algorithm to ensure that the actual current tracks the target current); FOC controller (core hardware unit for implementing FOC strategy, integrating MCU, register, peripheral interface, etc., used to execute current regulation, coordinate transformation, voltage utilization rate calculation, etc.); MCU (Microcontroller Unit, microcontroller, operation core of FOC controller, used to execute preset voltage utilization rate calculation formula, control current loop output, etc. instructions, such as using 32-bit industrial MCU to ensure real-time operation).

[0045] Optionally, when the field-oriented control (FOC) system of the permanent magnet synchronous motor is running, first, the d-axis voltage component ud and the q-axis voltage component uq are obtained; the two voltage components are output by the current loop of the FOC system; the current loop generates ud (control magnetic field) and uq (control torque) through PI adjustment according to the deviation between the current instructions of the d-axis and the q-axis and the feedback current, and is temporarily stored in the voltage instruction register of the motor controller. The MCU of the motor controller directly reads ud and uq from the register without additional voltage sampling hardware, and reuses the output signals of the existing current loop of the FOC system, which reduces the hardware cost and circuit complexity, avoids electromagnetic interference caused by newly added hardware, and improves the stability of signal acquisition.

[0046] Optionally, after obtaining ud and uq, they are input into a preset voltage utilization rate calculation formula, wherein, in the present embodiment, the formula is The actual voltage utilization rate Us is obtained by the MCU performing the operation; the formula is designed based on the amplitude characteristics of the voltage vector in the d-q synchronous rotating coordinate system, which can convert ud and uq in the two-phase rotating coordinate system into a scalar parameter Us representing the overall voltage consumption; the MCU completes the operation in each FOC control period (such as 100 μs), ensuring that Us reflects the current voltage state of the motor in real time. For example, when the electric vehicle is cruising at high speed, the back electromotive force of the motor increases, which causes ud and uq to increase synchronously, and Us also increases. At this time, Us can be used to quickly judge whether the voltage is close to the bus safety threshold, providing accurate triggering basis for subsequent field weakening control, avoiding the hysteresis of traditional indirect estimation of voltage state depending on speed, ensuring the timeliness of voltage control in high-speed field weakening working conditions, and reducing the risk of voltage over-limit damage to the inverter.

[0047] In addition, the operation logic of the preset voltage utilization rate calculation formula is stored in a non-transitory computer readable storage medium, and the MCU can flexibly call or modify the formula parameters according to the parameters (such as rated voltage and rated current) of different motors, adapt to permanent magnet synchronous motors of different power levels such as 10 kW vehicle motors and 50 kW industrial motors, and improve the universality of the scheme; The present embodiment is automatically completed by the motor controller without human intervention, reduces human operation errors, ensures the consistency and accuracy of Us calculation, provides reliable voltage state basis for closed-loop control links such as field weakening control and fault diagnosis of the FOC system, and finally ensures the stable operation of the motor in the full speed range (especially in the high-speed field weakening working condition), thereby improving the reliability and adaptability of the motor control system.

[0048] Further, based on the above, in some feasible embodiments, the step C201 comprises the following implementation steps D301 to E304.

[0049] Step D301: Obtain the d-axis reference current, q-axis reference current, and three-phase stator current of the motor control system; Step D302: Transform the three-phase stator current into the synchronous rotating coordinate system through coordinate transformation to obtain the d-axis feedback current and q-axis feedback current in the synchronous rotating coordinate system; Step D303: Calculate the deviation between the d-axis reference current and the d-axis feedback current to obtain the second deviation value, and calculate the deviation between the q-axis reference current and the q-axis feedback current to obtain the third deviation value; Step D304: Perform proportional integration on the second and third deviation values ​​to obtain the d-axis voltage component and the q-axis voltage component.

[0050] Optionally, the d-axis reference current (Idref), the target reference value of the d-axis current, is used to set the motor's magnetic field strength. It is determined by the "current command lookup table allocation" module based on the torque command and speed. For example, it is set to -50A during field weakening control to weaken the magnetic field, and to 0A during non-field weakening control to maintain the rated magnetic field. The q-axis reference current (Iqref), the target reference value of the q-axis current, directly determines the motor's output torque and is linearly related to the torque command. For example, when an electric vehicle requires 100 N·m of torque to start, Iqref is set to 80A. The three-phase stator currents: ia, ib, ic, are the actual currents flowing through the A, B, and C phase windings of the motor stator, reflecting the real-time operating status of the motor. They are collected by current sensors, and the sampling accuracy must meet ±1%FS to ensure feedback accuracy. The coordinate transformation: ABC→dq transformation, transforms the three-phase stationary coordinates... The logic for converting ia, ib, and ic in the abc coordinate system to current in the synchronous rotating coordinate system (dq) is as follows: The synchronous rotating coordinate system is synchronized with the motor rotor speed, the d-axis is aligned with the direction of the permanent magnet magnetic field, and the q-axis is perpendicular to the d-axis. The synchronous rotating coordinate system (dq coordinate system) rotates synchronously with the motor rotor. Through coordinate transformation, it converts the three-phase alternating current into DC components, achieving independent control of the magnetic field and torque. It is the core coordinate system of the FOC strategy. The d-axis feedback current (idfb) is the actual d-axis current value obtained after coordinate transformation, used to compare with Idref to form closed-loop control, reflecting the current actual magnetic field strength. The q-axis feedback current (idfb) is the actual q-axis current value obtained after coordinate transformation, used to compare with Iqref to form closed-loop control, reflecting the current actual torque output capability. The second deviation value is ΔI. d The difference between Idref and idfb, i.e., ΔI d =Idref-idfb), used to characterize the deviation between the magnetic field target and the actual state, providing a basis for d-axis voltage adjustment); the third deviation value: ΔI q The difference between Iqref and Iqfb, i.e., ΔI q= Iqref-Iqfb, for representing the deviation of torque target and actual state, providing the basis for q-axis voltage regulation; proportional integral: (PI, Proportional-Integral, a closed-loop control algorithm, the proportional element outputs the adjustment amount in real time according to the deviation, and the integral element accumulates the historical deviation to eliminate the steady-state error, which is used here to process ΔI d , ΔI q and output voltage components; current sensor: a hardware element for collecting ia, ib, and ic, such as a Hall current sensor, installed on the three-phase line between the inverter and the motor.

[0051] Optionally, in the operation of the permanent magnet synchronous motor FOC system, first, the d-axis reference current Idref, the q-axis reference current Iqref, and the three-phase stator currents ia, ib, and ic need to be obtained: Idref and Iqref are generated by the "current command lookup table distribution" module according to the torque command (such as the acceleration pedal signal of an electric vehicle) sent by the upper computer and the motor speed, ensuring that the magnetic field and torque meet the operation requirements (such as setting Idref to -80A to weaken the magnetic field and Iqref to 30A to maintain the cruise torque when cruising at high speed); ia, ib, and ic are collected in real time by the current sensor, and the sampling frequency is synchronized with the FOC control period (such as 100μs), providing real actual current signals for current closed-loop feedback. This acquisition process through the combination of "command generation + actual sampling" lays the foundation for subsequent closed-loop control, avoids control deviation caused by lack of actual current feedback, and improves control accuracy.

[0052] Optionally, ia, ib, and ic are converted into idfb and Iqfb in the synchronous rotating coordinate system through ABC→dq coordinate transformation: coordinate transformation is based on the real-time angle θ e of the motor rotor (collected by a position sensor such as a resolver), and through a pre-set transformation matrix (such as Clark transformation + Park transformation), the three-phase alternating ia, ib, and ic are converted into direct-current idfb and Iqfb.

[0053] This embodiment realizes "alternating signal direct current" through conversion, allowing the control of magnetic field (d-axis) and torque (q-axis) to be completely independent - adjusting Idref only affects the magnetic field, and adjusting Iqref only affects the torque, avoiding the coupling interference of magnetic field and torque in traditional three-phase control, and significantly improving the control flexibility and stability of the motor under different working conditions (such as starting, accelerating, and cruising).

[0054] Further, based on the above, in some possible embodiments, after the step of step S10, the following implementation steps E301 to E302 are further included.

[0055] Step E301: When the current target value is detected to be less than the preset current threshold value, the timing duration is accumulated, and the timing duration is compared with the preset timer overrun value; Step E302: When the timing duration is greater than the preset timer overrun value, it is determined that the motor control system has a fault.

[0056] Optionally, the timing duration: the length of time continuously accumulated from the first time when IdTgt is less than IdMin, used to record the duration of the abnormal state of IdTgt; the preset timer overrun value: TIMOUT DUR (Timer Timeout Duration: preset timer overrun value), a preset time threshold value used to distinguish whether the abnormality of IdTgt is a transient disturbance or a continuous fault, the value is determined based on the maximum transient disturbance duration of the system, such as 500 μs; the motor control system: refers to the permanent magnet synchronous motor FOC system, FOC (Field-Oriented Control, Field-Oriented Control), a system that realizes independent control of magnetic field and torque by decomposing stator current into d-q synchronous rotating coordinate system; fault: an abnormal state in the FOC system caused by hardware or software abnormalities, resulting in continuous exceeding of IdTgt in the safe range.

[0057] Optionally, in the permanent magnet synchronous motor FOC system, when IdTgt (current target value) is detected to be less than IdMin (preset current threshold value, such as -150 A), the system starts the timing module, and the timing duration is accumulated according to the system clock period (such as 100 μs) from the time when IdTgt first satisfies "less than IdMin"; if IdTgt is temporarily lower than IdMin due to electromagnetic radiation, short-time load fluctuation or other transient disturbances (such as only lasting for 100 μs), the timing duration is only accumulated to 100 μs, and this process can filter transient disturbances and avoid misjudgment as a fault, thereby improving the anti-interference ability of fault judgment.

[0058] Optionally, the system compares the accumulated timing duration with TIMOUT DUR (preset timer overrun value, such as 500 μs): if the timing duration ≤ TIMOUT DUR, it is determined to be a transient disturbance, and no fault alarm is triggered; if the timing duration > TIMOUT DUR, it means that IdTgt is continuously abnormal, and it is determined that the FOC system has a field weakening overrun fault, and protection measures (such as speed reduction, torque limiting) need to be started. Since MOUT DUR covers the maximum transient disturbance duration of the system (such as industrial electromagnetic interference usually ≤ 300 μs), this comparison ensures that only continuous faults are identified, avoids the misjudgment problem of traditional single threshold judgment, and improves the reliability of fault diagnosis.

[0059] The determination mode of the embodiment is suitable for scenarios such as electric vehicles and industrial frequency converters, and can avoid motor operation interruption (such as unexpected speed reduction of an electric vehicle) caused by misjudgment, thereby improving user experience and system stability; the timing and determination logic is implemented by a software module, stored in a non-transitory computer-readable storage medium, and executed by an MCU, without the need for additional hardware, thereby reducing system cost and complexity.

[0060] Further, based on the content of any of the above embodiments, in some feasible embodiments, the step S20 includes the following implementation steps F41-F42.

[0061] Step F41: when the current target value is first detected to be less than the preset current threshold, start counting the number of times that the current target value is less than the preset current threshold in a preset time period; Step F42: compare the number of times with a preset number of times, wherein the preset number of times is a number threshold corresponding to a preset timer overflow value.

[0062] Optionally, the preset time period is a pre-set statistical time window for limiting the statistical range of the number of times of IdTgt abnormalities, to avoid fault delay determination caused by long-time statistics; in the embodiment, the preset time period is set to 500 microseconds, corresponding to 5 control periods of the FOC system, and each control period is 100 microseconds; the number of times is the cumulative number of times that IdTgt is less than IdMin in the preset time period, reflecting the frequency of the abnormal state of IdTgt; the preset number of times is a number threshold corresponding to a preset timer overflow value, for distinguishing whether the abnormality of IdTgt is sporadic interference or a persistent fault; in the embodiment, the preset number of times is set to 5, matching the 5 control periods of the preset time period, that is, the preset timer overflow value is 5; the preset timer overflow value is a TIMOUT_VAL (Timer Timeout Value: pre-set counting threshold), for defining the critical value of “abnormal number of times reaching the fault standard”; in the embodiment, the preset timer overflow value is set to 5, consistent with the number of control periods in the preset time period; and the FOC control period is the time interval for executing current regulation and coordinate transformation of the FOC system once; in the embodiment, the FOC control period is set to 100 microseconds, to ensure control real-time performance.

[0063] Optionally, during the operation of the permanent magnet synchronous motor FOC system, when the MCU first detects that IdTgt (target current value) is less than IdMin (preset current threshold, such as -150A), it immediately activates the statistical function: taking the FOC control cycle (100μs) as the unit, within a preset time period (500μs), after each IdTgt detection, if it is determined that IdTgt is still less than IdMin, the count is incremented by 1. For example, if IdTgt is lower than IdMin for only one control cycle due to high-frequency electromagnetic interference in the industrial environment, the count is only incremented to 1, not reaching the preset number (5 times). In this case, it is determined to be an occasional interference, and no fault alarm is triggered. This "time period limit + count statistics" method, compared with single detection or simple timing, can more accurately filter instantaneous fluctuations in a short period of time, avoid misjudging faults due to occasional interference, and improve the anti-interference capability of fault judgment.

[0064] Optionally, after the statistics are completed, the MCU will compare the number of occurrences with the preset number (5 times, i.e., the preset counter over-limit value of 5): if the number of occurrences is less than or equal to the preset number, it means that the abnormality of IdTgt has not formed a continuous state within the preset time period, and it is judged as normal fluctuation, and the system continues to operate normally; if the number of occurrences is greater than the preset number, it means that IdTgt is continuously abnormal within the preset time period, and it is determined that there is a weak magnetic over-limit fault in the FOC system, and protection measures need to be activated immediately (such as reducing the motor speed to a safe range and limiting torque output); since the preset number and the preset time period are strictly matched (5 times corresponds to 5 control cycles), it ensures that only "continuous and frequent" abnormalities will be judged as faults, avoiding the misjudgment problem of "single abnormality is an alarm" in traditional systems, especially suitable for scenarios with stringent requirements for fault diagnosis reliability, such as high-speed cruising of electric vehicles, and ensuring the stable operation of the motor under critical operating conditions.

[0065] Meanwhile, the statistical and comparison logic is implemented through a software module and stored in a non-transitory computer-readable storage medium. It is executed directly by the MCU without the need for additional hardware such as an independent counter chip, effectively reducing system hardware costs and circuit complexity. Furthermore, the preset time period and preset number of times can be flexibly adjusted according to motor parameters (such as rated speed and anti-interference capability). For example, it can be set to 500μs / 5 times when adapting to a 10kW automotive motor, and 1ms / 10 times when adapting to a 50kW industrial motor, improving the versatility of the solution.

[0066] Optionally, such as Figure 2 As shown, Figure 2 This is the logic diagram for determining the weak magnetic field over-limit in this application. In the diagram, the d-axis voltage component ud and the q-axis voltage component uq are first processed by...

[0067] The actual voltage utilization rate Us is obtained, and the Us is subtracted from the voltage utilization rate reference value Usref by means of a minus sign, and the obtained deviation is input into a PI controller (proportional integral controller); the output of the PI controller is added to the d-axis reference current Idref obtained by means of a field weakening table query by means of a plus sign, to generate a d-axis current target value IdTgt; then, the IdTgt enters a comparison module and is compared with a d-axis current minimum value IdMin by means of a less-than sign: if IdTgt<IdMin, a counter CNT is triggered to count; the count value of the counter CNT is compared with a pre-designed counter over-limit value (TIMOUT_VAL) by means of a greater-than sign: if the count value is greater than (TIMOUT_VAL), a field weakening over-limit fault signal is output, indicating that the system has a field weakening over-limit fault.

[0068] The embodiment ensures the timeliness of fault diagnosis, and takes into account the anti-interference capability and cost control, and finally improves the reliability and engineering application value of the motor control system.

[0069] In addition, the application also provides a fault diagnosis system, and the motor control system comprises a controller, please refer to Figure 3 , Figure 3 is a structural schematic diagram of the controller involved in the embodiment scheme of the application. The controller provided by the application comprises: The acquisition module H01 is configured to acquire a current target value in a field weakening control process of the motor control system, and compare the current target value with a preset threshold value; The comparison module H02 is configured to, when detecting that the current target value is less than the preset current threshold value, count to obtain a count value, and compare the count value with a pre-designed counter over-limit value; The determination module H03 is configured to, when the count value is greater than the pre-designed counter over-limit value, determine that the motor control system has a fault.

[0070] The fault diagnosis system provided by the application adopts the fault diagnosis method in the above embodiment, and can solve the technical problem that the traditional dependence on additional special sensors cannot be broken through. Compared with the prior art, the fault diagnosis system provided by the application has the same beneficial effects as the fault diagnosis device and method provided by the above embodiment, and other technical features in the fault diagnosis device are the same as the features disclosed in the previous embodiment method, which will not be described here.

[0071] Further, based on the above motor control system, another embodiment of the motor control system of the application is proposed, please refer to Figure 4 , Figure 4 is a control flow diagram of a permanent magnet synchronous motor FOC system involved in the application, and the motor control system comprises: A current controller 10, a first end of the current controller 10 is connected with the input port, a second end of the current controller 10 is connected with the controller; A first converter 20, a first end of the first converter 20 is connected with the second end of the current controller 10; An inverter 30, a first end of the inverter 30 is connected with a second end of the first converter 20; A second converter 50, a first end of the second converter 50 is connected with a third end of the current controller 10, a second end of the second converter 50 is connected with a second end of the inverter 30, a third end of the second converter 50 is connected with a third end of the first converter 20; A position sensor 40, a first end of the position sensor 40 is connected with the motor, a second end of the position sensor 40 is connected with the third end of the first converter 20 and the third end of the second converter 50.

[0072] Optionally, the current controller 10 is a control unit for closed-loop regulation of the current signal, receives an input instruction and a feedback signal, outputs a regulated current control signal, and ensures that the motor current tracks a target value; the first converter 20 is a Clark-Park converter, which realizes current / voltage conversion from a three-phase stationary coordinate system to a synchronous rotating coordinate system, and provides a coordinate conversion basis for field-oriented control (FOC); the inverter 30 is a power electronic device that converts direct-current power into three-phase alternating-current power, receives a control signal of the first converter 20, and drives the motor stator winding to control the motor magnetic field and torque; the second converter 50 is a Park-Clark converter, which realizes current / voltage inversion from a synchronous rotating coordinate system to a three-phase stationary coordinate system, and converts d-q axis voltage instructions into three-phase voltage instructions to control the inverter 30; the position sensor 40 is a rotary transformer or an encoder, which is installed at the shaft end of the motor, detects the position and speed signal of the motor rotor in real time, and provides a rotor angle basis for coordinate conversion; the input port is an interface for receiving external control instructions or reference signals, which can receive torque and speed instructions of the upper computer, and provides control targets for the current controller 10; the controller is a hardware unit integrated with an MCU, which executes current closed-loop algorithms and coordinate conversion logic, and is the control center of the system; the motor is a permanent magnet synchronous motor in this embodiment, which realizes electrical energy and mechanical energy conversion through electromagnetic interaction between the stator winding and the rotor permanent magnet, and is an executive mechanism of the system.

[0073] Optionally, in the field-oriented control (FOC) system of the permanent magnet synchronous motor, the input port receives an external control instruction (such as a torque instruction corresponding to the acceleration pedal of an electric vehicle) and transmits it to the first end of the current controller 10; the second end of the current controller 10 is connected to the first end of the first converter 20, and the third end is connected to the first end of the second converter 50; the current controller 10 outputs d-axis and q-axis current control signals based on the input instruction and the feedback current signal, one of which is sent to the first converter 20, and the other is sent to the second converter 50.

[0074] Optionally, the second end of the first converter 20 is connected to the first end of the inverter 30, and the third end is connected to the second end of the position sensor 40 and the third end of the second converter 50; the first converter 20 receives the d-q axis current control signal of the current controller 10, and combines the motor rotor angle feedback by the position sensor 40 (the position sensor 40 detects the motor rotor to ensure the synchronization of coordinate transformation), converts the d-q axis current control signal into a three-phase current instruction and transmits it to the inverter 30; the inverter 30 drives the internal power switch device based on the three-phase current instruction, converts the DC bus power into three-phase alternating current input to the motor stator winding, and controls the motor magnetic field and torque.

[0075] Optionally, the second end of the second converter 50 is connected to the second end of the inverter 30, for receiving the three-phase current (or voltage) feedback signal output by the inverter 30; the second converter 50 converts the three-phase feedback signal into a d-q axis feedback signal in combination with the rotor angle of the position sensor 40 and transmits it to the third end of the current controller 10; the current controller 10 compares the d-q axis control signal with the feedback signal, generates a deviation and performs proportional integral adjustment, realizes current closed-loop control, and ensures that the motor current accurately tracks the target value.

[0076] Optionally, the first end of the position sensor 40 is connected to the motor, which detects the motor rotor position and speed in real time, provides rotor angle information for coordinate transformation of the first converter 20 and the second converter 50, and ensures the accuracy of "field orientation" in the FOC strategy - only accurate rotor angle detection can accurately align the d-axis with the direction of the permanent magnet magnetic field, and the q-axis can be perpendicular to the d-axis, thereby realizing independent control of the magnetic field and torque.

[0077] This embodiment achieves precise FOC control of a permanent magnet synchronous motor through a closed-loop link of "input port - current controller - converter - inverter - position sensor": the closed-loop regulation of the current controller ensures current tracking accuracy, the coordinate transformation of the first and second converters decouples the magnetic field and torque, the power electronic conversion of the inverter provides driving power to the motor, and the angle feedback of the position sensor ensures the synchronization of coordinate transformation. For example, in electric vehicle scenarios, this structure allows the motor to respond quickly to torque commands during start-up (without jerking), accurately control the field weakening current during high-speed cruising (improving range), and simultaneously prevent current over-limit damage to the motor or inverter. The entire control logic software module is stored in a non-transitory computer-readable storage medium and executed by the controller MCU, eliminating the need for additional complex hardware, reducing system cost and complexity, and the synergistic effect of each module improves the dynamic responsiveness and control accuracy of the motor control system, making it suitable for scenarios with stringent motor control requirements, such as industrial drives and electric vehicles. Optionally, the current controller 10 includes a "current loop" module: an adjustment unit that uses closed-loop control to make the actual current track the target current; a first converter 20: a "dq→αβ" coordinate transformation module, a conversion unit that converts voltage in a rotating coordinate system to voltage in a stationary coordinate system, where the α and β axes are the coordinate axes of a two-phase stationary coordinate system; a coordinate transformation module; an inverter 30: a power electronic device that converts DC power to three-phase AC power; a position sensor 40: such as a resolver, i.e., a rotary transformer, a sensor used to accurately measure the rotor position; and a second converter 50: an "abc→dq" coordinate transformation module, a conversion unit that converts current in a three-phase stationary coordinate system to current in a rotating coordinate system.

[0078] like Figure 4 As shown, Figure 4 The control flowchart of the permanent magnet synchronous motor FOC system involved in this application is as follows: Specifically, the host computer (the upper-level control device that issues control commands, such as the vehicle controller of an automobile) sends a torque command Teref (the target value of the desired motor output torque). After inputting into the "current command lookup table allocation" module (a functional module that converts the torque command into the corresponding current command according to a preset "torque-current" mapping table), it outputs the d-axis current command Idref (the target current of the excitation axis, used to adjust the motor magnetic field) and the q-axis current command Iqref (the target current of the torque axis, which directly affects the motor output torque). These two current commands enter the current controller 10, and after current loop adjustment (usually through PI control, i.e., proportional-integral control, to quickly eliminate current deviation to achieve tracking), it outputs the d-axis voltage ud (the voltage command of the excitation axis) and the q-axis voltage uq (the voltage command of the torque axis). Subsequently, ud and uq are correlated with the angle θ. e (The real-time position and angle of the motor rotor are used for coordinate system synchronization.) Input the first converter 20 to obtain the α-axis voltage. β-axis voltage and input the two voltages into a "SVPWM (Space Vector Pulse Width Modulation: a modulation technology for realizing efficient driving of a motor by controlling a voltage vector trajectory)" module; the SVPWM module outputs six complementary PWM signals (pulse width modulation signals for controlling the size of a voltage by adjusting the pulse width) to an inverter 30 (a power electronic device for converting a direct-current power supply into a three-phase alternating-current power supply), and the inverter 30 converts the direct-current voltage into a three-phase alternating-current voltage to drive a motor (here, a permanent magnet synchronous motor, a synchronous motor using a permanent magnet to generate a magnetic field) to operate; three-phase currents ia, ib, and ic (currents in A, B, and C three-phase windings of a stator of the motor) output by the motor when operating are input into a second converter 50 (a conversion unit for converting currents in a three-phase stationary coordinate system into currents in a rotating coordinate system), and the module simultaneously receives an angle θ e , and outputs a feedback d-axis current idfb (an actual current of an excitation axis) and a q-axis current iqfb (an actual current of a torque axis) back to the current controller 10 to form a current closed-loop control (to ensure that the actual current is consistent with the command current by adjusting the output in real time through feedback); at the same time, a position sensor 40 (such as a resolver, a sensor for accurately measuring the rotor position) collects an actual angle θ s of the motor and feeds it back to the first converter 20 and other links to provide a synchronous rotating angle reference for coordinate transformation, guarantee the accuracy of coordinate transformation in FOC control, and then realize accurate regulation and control of the torque and speed of the permanent magnet synchronous motor to support efficient and stable operation of the motor in scenarios such as electric vehicles.

[0079] Optionally, compared with the prior art, the fault diagnosis system provided in the application has the same beneficial effects as the fault diagnosis device and method provided in the above-mentioned embodiments, and other technical features in the fault diagnosis device are the same as the features disclosed in the last embodiment method, which will not be repeated here.

[0080] In addition, the application also provides a fault diagnosis device. Please refer to Figure 5 , Figure 5 , which is a structural schematic diagram of the fault diagnosis device involved in the embodiment scheme of the application. The device of the embodiment of the application can be a device for locally running the fault diagnosis method.

[0081] The application provides a fault diagnosis device, which comprises at least one processor and a memory in communication connection with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the fault diagnosis device method in Embodiment I.

[0082] The following will be described with reference to Figure 5 ,Figure 5 This is a schematic diagram of the structure of a fault diagnosis device according to an embodiment of this application, showing a structural schematic diagram suitable for implementing the fault diagnosis device of this application. The fault diagnosis device in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), vehicle terminals (such as vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 5 The fault diagnosis device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0083] like Figure 5 As shown, the fault diagnosis device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the fault diagnosis device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following devices may be connected to the I / O interface 1006: input devices 1007 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; storage devices 1003 including, for example, magnetic tape, hard disk, etc.; and communication devices 1009. Communication device 1009 allows the fault diagnosis device to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows a fault diagnosis device with various devices, it should be understood that it is not required to implement or possess all of the devices shown. More or fewer devices may be implemented or possessed alternatively.

[0084] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program codes for executing the method shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network through a communication device, or installed from the storage device 1003, or installed from the ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiments disclosed in the present application are executed.

[0085] The fault diagnosis device provided in the present application adopts the fault diagnosis method in the above-mentioned embodiments, and can solve the technical problem of low efficiency of the fault diagnosis device. Compared with the prior art, the fault diagnosis device provided in the present application has the same beneficial effects as the fault diagnosis method provided in the above-mentioned embodiments, and other technical features in the fault diagnosis device are the same as the features disclosed in the previous embodiment method, which will not be described here.

[0086] In addition, the present application provides a computer readable storage medium. The computer readable storage medium stores a fault diagnosis program, and the fault diagnosis program is executed by a processor to implement the steps of the above-mentioned fault diagnosis method.

[0087] It should be noted that in this paper, the term "including" "containing" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or system. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or system including the element.

[0088] The above-mentioned serial numbers of the embodiments of the present application are only for description, not representing the advantages and disadvantages of the embodiments.

[0089] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment method can be realized by means of software and necessary general hardware platform, of course, it can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a computer readable storage medium (such as a ROM / RAM, a magnetic disk, an optical disk) as described above, and includes a plurality of instructions for causing an apparatus (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in the embodiments of the present application.

[0090] The preferred embodiments of the present application have been described above with the illustrated embodiments, and are not intended to limit the scope of patent protection for the present application. Any equivalent structure or equivalent process variations, which directly or indirectly incorporate the contents of the specification and drawings of the present application, are also intended to be included within the scope of patent protection for the present application.

Claims

1. A failure diagnosis method characterized by comprising: The method is applied to a motor control system, and the method comprises: obtaining a current target value of a field weakening control process in the motor control system, and comparing the current target value with a preset threshold value; when it is detected that the current target value is less than the preset current threshold value, performing count accumulation to obtain a count value, and comparing the count value with a preset counter over-limit value; when the count value is greater than the preset counter over-limit value, determining that the motor control system has a fault.

2. The failure diagnosing method according to Claim 1, wherein Before the step of obtaining the current target value of the field weakening control process in the motor control system, and comparing the current target value with a preset threshold value, the method further comprises: obtaining an actual voltage utilization rate of the field weakening control process in the motor control system and a preset voltage safety threshold value, and obtaining a first deviation value by subtracting the actual voltage utilization rate from the preset voltage safety threshold value; performing proportional integration on the first deviation value to obtain a field weakening current adjustment amount; obtaining a preset basic field weakening current value, adding the field weakening current adjustment amount to the preset basic field weakening current value to generate the current target value.

3. The failure diagnosing method according to claim 2, wherein Before the step of obtaining the actual voltage utilization rate of the field weakening control process in the motor control system and the preset voltage safety threshold value, the method further comprises: obtaining a d-axis voltage component and a q-axis voltage component of the motor control system; inputting the d-axis voltage component and the q-axis voltage component into a preset voltage utilization rate calculation formula to obtain the actual voltage utilization rate.

4. The failure diagnosing method according to claim 3, wherein The step of obtaining the d-axis voltage component and the q-axis voltage component in the synchronous rotating coordinate system further comprises: obtaining a d-axis reference current and a q-axis reference current of the motor control system and three-phase stator currents; converting the three-phase stator currents to the synchronous rotating coordinate system through coordinate transformation to obtain a d-axis feedback current and a q-axis feedback current in the synchronous rotating coordinate system; calculating a second deviation value by calculating a deviation between the d-axis reference current and the d-axis feedback current, and calculating a third deviation value by calculating a deviation between the q-axis reference current and the q-axis feedback current; performing proportional integration on the second deviation value and the third deviation value to obtain the d-axis voltage component and the q-axis voltage component.

5. The method of claim 1, wherein the step of diagnosing the fault comprises the step of: After the step of obtaining the current target value of the field weakening control process in the motor control system, and comparing the current target value with a preset threshold value, the method further comprises: ​ when it is detected that the current target value is less than the preset current threshold value, performing timing accumulation to obtain a timing duration, and comparing the timing duration with a preset timer over-limit value; when the timing duration is greater than the preset timer over-limit value, determining that the motor control system has a fault.

6. The failure diagnosing method according to Claim 1, wherein The step of, when it is detected that the current target value is less than the preset current threshold value, performing count accumulation to obtain a count value, and comparing the count value with a preset counter over-limit value, comprises: when the current target value is detected to be less than the preset current threshold value for the first time, starting to count a number of times that the current target value is less than the preset current threshold value in a preset time period; comparing the number of times with a preset number of times, wherein the preset number of times is a number of times threshold value corresponding to the preset counter over-limit value.

7. An electric motor control system characterized by comprising: The motor control system comprises a controller, the controller comprising: an acquisition module configured to acquire a current target value of a field weakening control process in the motor control system, and compare the current target value with a preset threshold value; a comparison module configured to, when detecting that the current target value is less than the preset threshold value, perform counting accumulation to obtain a count value, and compare the count value with a preset counter over-limit value; a determination module configured to, when the count value is greater than the preset counter over-limit value, determine that the motor control system has a fault.

8. The motor control system of claim 7, wherein, The motor control system further comprises: a current controller, a first end of the current controller being connected with an input port, and a second end of the current controller being connected with the controller; a first converter, a first end of the first converter being connected with a second end of the current controller; an inverter, a first end of the inverter being connected with a second end of the first converter; a second converter, a first end of the second converter being connected with a third end of the current controller, a second end of the second converter being connected with a second end of the inverter, and a third end of the second converter being connected with a third end of the first converter; a position sensor, a first end of the position sensor being connected with a motor, and a second end of the position sensor being connected with the third end of the first converter and the third end of the second converter.

9. A failure diagnosing apparatus characterized by comprising: The fault diagnosis device comprises a memory, a processor, and a fault diagnosis program stored on the memory and executable on the processor, and the processor implements the steps of the fault diagnosis method according to any one of claims 1 to 7 when executing the fault diagnosis program.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a fault diagnosis program, and the fault diagnosis program implements the steps of the fault diagnosis method according to any one of claims 1 to 7 when executed by a processor.

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