Circuit protection control method and system for motor controller

Abstract

The present invention provides a circuit protection control method and system for a motor controller, comprising the following steps: calibrating a first braking torque-speed curve and a second braking torque-speed curve for the motor in the ASC and SPO states; calibrating a safety torque curve, wherein the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve and the second braking torque-speed curve intersect at a second intersection; determining a first speed threshold and a second speed threshold; detecting the current speed of the motor, and executing SPO protection when the current speed is less than or equal to the first speed threshold; executing ASC or SPO protection when the current speed is greater than the first speed threshold and less than the second speed threshold; executing ASC protection when the current speed is greater than or equal to the second speed threshold. After adopting the above technical solution, it is suitable for active safety control of motor controllers of various pure electric / hybrid vehicles, and provides flexible control logic for various operating conditions.

Description

Technical Field

[0001] The present invention relates to the field of motor control, and in particular to a circuit protection control method and system for a motor controller. Background Art

[0002] In new energy vehicle applications, the normal operation of the electric drive system composed of motors and motor controllers is extremely important. Once the electric drive system fails, it may cause device damage or even casualties. Therefore, in the event of a failure in the electric drive system, it is necessary to provide fault protection and enter active safety control to output zero torque or acceptable safety braking torque to slowly stop the vehicle, so that the driver can safely leave the lane. The two most common active safety control measures are SPO (Switching Pulse Off), which is a fully closed state, and ASC (Active Short Circuit), which is an active short circuit. SPO is implemented by disconnecting all switch tubes, and ASC is achieved by short-circuiting the upper bridge or the lower bridge to separate other high-voltage components such as batteries from the electric drive system.

[0003] In the SPO state, the back electromotive force of the permanent magnet synchronous motor increases with the speed. Excessive back electromotive force may reverse charge the battery through the rectifier diode of the three-phase bridge, causing damage to other devices; while ASC has a higher braking torque at medium and low speeds, affecting safe operation, and the short-circuit current generated in the ASC state is also a damage to the motor and motor controller.

[0004] In the prior art, the motor controller determines whether to enter the above two states by setting a fixed speed value. When the motor speed reaches or exceeds the fixed speed value, ASC is executed, and when it is lower than the fixed speed, SPO is executed. Therefore, it is impossible to ensure zero torque or safe braking torque under complex application conditions, especially in the medium speed range, and avoid damage to the device caused by excessive reverse charging voltage.

[0005] Therefore, a new circuit protection control method and system for a motor controller is needed to clarify the characteristics of ASC / SPO in the full speed range, combine the measured voltage, speed or other related variables, meet zero torque or control the braking torque within the safe torque under complex application conditions, and avoid device damage caused by excessive reverse charging voltage. Summary of the invention

[0006] In order to overcome the above technical defects, the purpose of the present invention is to provide a circuit protection control method and system for a motor controller, which is suitable for active safety control of motor controllers of various pure electric / hybrid vehicle models and provides flexible control logic for various operating conditions.

[0007] The present invention discloses a circuit protection control method for a motor controller, comprising the following steps:

[0008] Calibrate the relationship between the braking torque and the motor speed of a motor in an active short circuit and full shut-off state to form a first braking torque-speed curve and a second braking torque-speed curve;

[0009] Calibrate the safety torque curve of the motor within the braking torque-speed curve, so that the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve intersects with the second braking torque-speed curve at a second intersection;

[0010] Determine the motor speeds corresponding to the first intersection and the second intersection as the first speed threshold and the second speed threshold;

[0011] Detecting a current rotation speed of the motor, and comparing the current rotation speed with a first rotation speed threshold and / or a second rotation speed threshold;

[0012] When the current speed is less than or equal to the first speed threshold, the motor controller performs full shutdown protection on the motor;

[0013] When the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs active short circuit or full shutdown protection on the motor;

[0014] When the current rotation speed is greater than or equal to the second rotation speed threshold, the motor controller performs active short-circuit protection on the motor.

[0015] Preferably, when the current speed is greater than the first speed threshold and less than the second speed threshold, the step of the motor controller performing active short circuit or full shutdown protection on the motor includes:

[0016] When the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs active short-circuit protection on the motor, or

[0017] When the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs full shutdown protection on the motor, or

[0018] When the current speed is greater than the first speed threshold and less than the second speed threshold, detecting the DC voltage of the motor, and comparing the DC voltage with the reverse charging voltage at the current speed of the motor;

[0019] When the DC voltage is less than or equal to the reverse charging voltage, the motor controller performs active short-circuit protection on the motor;

[0020] When the DC voltage is greater than or equal to the reverse charging voltage, the motor controller performs full shutdown protection on the motor.

[0021] Preferably, when the current speed is greater than the first speed threshold and less than the second speed threshold, before the step of detecting the DC voltage of the motor and comparing the DC voltage with the reverse charging voltage of the motor, the method further includes:

[0022] A voltage threshold is also provided in the motor controller;

[0023] Compare the reverse charging voltage of the motor with the voltage threshold;

[0024] When the reverse charging voltage is less than or equal to the voltage threshold, the motor controller performs full shutdown protection on the motor;

[0025] When the reverse charging voltage is greater than the voltage threshold, the DC voltage of the motor is detected and compared with the reverse charging voltage of the motor.

[0026] Preferably, the step of determining the motor speeds corresponding to the first intersection and the second intersection as the first speed threshold and the second speed threshold comprises:

[0027] Obtain a first motor speed and a second motor speed corresponding to the first intersection point and the second intersection point;

[0028] Acquire a first speed interval before and after the speed of the first motor and a second speed interval before and after the speed of the second motor based on a speed redundancy ratio;

[0029] The first speed interval and the second speed interval are defined as a first speed threshold and a second speed threshold.

[0030] Preferably, the method further comprises the following steps:

[0031] When the current speed jumps within or outside the first speed range, the motor controller is maintained to perform full shutdown protection on the motor;

[0032] When the current speed jumps within or outside the second speed range, the motor controller is maintained to perform active short-circuit protection on the motor.

[0033] Preferably, a time threshold is set in the motor controller, and when the motor controller performs full shutdown protection or active short-circuit protection on the motor, the time threshold will be maintained at least.

[0034] Preferably, the method further comprises the following steps:

[0035] Based on the change of the motor at different rotor temperatures, modifying the first braking torque-speed curve and the second braking torque-speed curve;

[0036] The first speed threshold value and the second speed threshold value are determined based on the rotor temperature.

[0037] The present invention also discloses a circuit protection control system of a motor controller. The motor controller is connected to a motor to control the working state of the motor. The motor controller includes:

[0038] A calibration module calibrates the relationship between the braking torque and the motor speed of the motor in the active short circuit and full shut-off states to form a first braking torque-speed curve and a second braking torque-speed curve and stores them, and the calibration module calibrates the safety torque curve of the motor in the braking torque-speed curve, so that the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve and the second braking torque-speed curve intersect at a second intersection;

[0039] A processing module determines that the motor speeds corresponding to the first intersection and the second intersection are the first speed threshold and the second speed threshold;

[0040] The control module detects the current speed of the motor and compares the current speed with a first speed threshold and / or a second speed threshold; when the current speed is less than or equal to the first speed threshold, the motor is fully shut down for protection; when the current speed is greater than the first speed threshold and less than the second speed threshold, the motor is actively short-circuited or fully shut down for protection; when the current speed is greater than or equal to the second speed threshold, the motor is actively short-circuited for protection.

[0041] Compared with the prior art, the above technical solution has the following beneficial effects:

[0042] 1. Optimize the entry conditions of ASC / SPO from two aspects: avoiding excessive braking torque and avoiding the influence of reverse EMF on the battery;

[0043] 2. Combine the measured voltage, speed and other conditions to flexibly determine the conditions for entering ASC / SPO to avoid excessive SPO back EMF causing reverse charging of the battery and causing other device problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic flow chart of a circuit protection control method for a motor controller in accordance with a preferred embodiment of the present invention;

[0045] Figure 2 A schematic diagram of a first braking torque-speed curve and a second braking torque-speed curve in accordance with a preferred embodiment of the present invention;

[0046] Figure 3 The figure is a flow chart of a circuit protection control method of a motor controller in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0047] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

[0048] Exemplary embodiments will be described in detail herein, examples of which 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 embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0049] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0050] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0051] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0052] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0053] In the following description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings. Therefore, "module" and "component" can be used interchangeably.

[0054] See also Figure 1 , is a flow chart of a circuit protection control method of a motor controller in accordance with a preferred embodiment of the present invention. In this embodiment, the circuit protection control method includes the following steps:

[0055] S100: Calibrate the relationship between the braking torque and the motor speed of a motor in an active short circuit and full shutdown state to form a first braking torque-speed curve and a second braking torque-speed curve

[0056] As mentioned above, in the event of a fault in the electric drive system, it is necessary to perform fault protection and enter active safety control. The two most common active protection measures are Switching Pulse Off (SPO) and Active Short Circuit (ASC). SPO is implemented by disconnecting all switching tubes; ASC is achieved by short-circuiting the upper bridge or the lower bridge to separate other high-voltage components such as the battery from the motor and controller. For a motor that needs to be controlled, calibrate the relationship between the braking torque and the motor speed of the motor in the ASC and SPO states. During the calibration, different motor speeds are used as the variables on the x-axis, and the braking torque is used as the variable on the y-axis, so as to calibrate the following: Figure 2 The first braking torque-speed curve and the second braking torque-speed curve are shown. That is to say, the first braking torque-speed curve and the second braking torque-speed curve respectively represent the braking torque that the motor will generate at different speeds under the ASC and SPO states. It can be seen from the first braking torque-speed curve that under the ASC state, as the motor speed increases, the braking torque will first rise and then decrease, and the braking torque is the largest in the low-speed area. It can be seen from the second braking torque-speed curve that under the SPO state, contrary to ASC, as the motor speed increases, the braking torque will continue to be close to 0, and as the motor speed continues to increase, if there is a reverse charging voltage, the braking torque will increase and change with the reverse charging situation. The first braking torque-speed curve and the second braking torque-speed curve are calibrated in the same coordinate axis to form a relationship between the braking torque and the motor speed.

[0057] It can be understood that the relationship between the back electromotive force and the motor speed of the above-mentioned motor in the fully closed state forms a back electromotive force-speed curve, and further calculation can form a back charging voltage-speed curve after the back electromotive force is rectified by a three-phase bridge.

[0058] S200: Calibrate the safety torque curve of the motor within the first braking torque-speed curve and the second braking torque-speed curve, so that the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve and the second braking torque-speed curve intersect at a second intersection.

[0059] A safety torque curve will be added to the first braking torque-speed curve and the second braking torque-speed curve in the same coordinate axis, and the safety torque value is defined according to the requirements of the vehicle manufacturer. Generally speaking, the safety torque value is a fixed value. Therefore, in the coordinate axis, the safety torque curve will be calibrated as a straight line almost parallel to the x-axis. As a result, the safety torque curve will intersect with the first braking torque-speed curve and the second braking torque-speed curve. And when the first braking torque-speed curve and the second braking torque-speed curve are originally calibrated, the above two will also intersect. On this basis, the intersection position of the safety torque curve and the first braking torque-speed curve is defined as the first intersection point, and the first braking torque-speed curve and the second braking torque-speed curve intersect at the second intersection point. It can be understood that due to the characteristics of the first braking torque-speed curve, it will intersect with the safety torque curve at two points. For this, the first intersection point along the direction of increasing motor speed can usually be selected as the first intersection point.

[0060] S300: Determine that the motor speeds corresponding to the first intersection point and the second intersection point are the first speed threshold and the second speed threshold

[0061] After having the above-mentioned first intersection and second intersection, the x-axis positions corresponding to the first intersection and the second intersection, that is, the corresponding motor speeds are defined as the first speed threshold and the second speed threshold respectively.

[0062] S400: Detecting the current speed of the motor and comparing the current speed with the first speed threshold and / or the second speed threshold

[0063] After obtaining the above-mentioned first speed threshold and second speed threshold, the current speed of the motor will be detected in real time, and the detection result will be compared with the first speed threshold and / or the second speed threshold. It can be understood that since the first speed threshold and the second speed threshold divide the motor speed into three gears, when comparing, it can be compared with the first speed threshold and the second speed threshold at the same time, or it can be compared with the first speed threshold and the second speed threshold in sequence to save control process. S410: When the current speed is less than or equal to the first speed threshold, the motor controller performs full shutdown protection on the motor.

[0064] When the comparison result is that the current speed is less than or equal to the first speed threshold, it means that the current speed of the motor is relatively small and falls into the area where the braking torque is relatively large in the ASC state and relatively small in the SPO state. In this regard, the motor controller will perform full-shutdown SPO protection on the motor, so that the control of the motor is such that its braking torque is relatively small and the braking torque is ensured to be less than the safety torque.

[0065] S420: When the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs active short circuit or full shutdown protection on the motor.

[0066] When the comparison result is that the current speed is greater than the first speed threshold and less than the second speed threshold, it means that the current speed is in the mid-range area. In this area, the braking torque in the ASC and SPO states is less than the safety torque. Therefore, in terms of the safety torque dimension, it is acceptable to select either ASC or SPO protection measures, and either one of them can be selected as the protection logic.

[0067] S430: When the current speed is greater than or equal to the second speed threshold, the motor controller performs active short-circuit protection on the motor

[0068] When the current speed is greater than or equal to the second speed threshold, it means that the current speed is relatively high and falls into a high-end area where the braking torque is relatively small in the ASC state and the reverse charging voltage is high in the SPO state, resulting in a relatively large braking torque. In this regard, the motor controller will perform ASC protection on the motor, so that the motor is controlled so that its braking torque is relatively small and the braking torque is ensured to be less than the safety torque.

[0069] In summary, in the present invention, a fixed speed is no longer used as a fixed standard for controlling the motor to enter the ASC and SPO states. Instead, the safety torque is used as a constant guarantee source, thereby avoiding the problem in the original solution that the safety torque cannot adapt to changes in fixed speeds for motors of different models and in different usage scenarios. In addition, further, for different types of motors, the calibrated curve is more personalized, and under different curves, intelligent switching of the ASC and SPO states can still be achieved under safe driving.

[0070] It is understandable that before the above steps S410-430, it is necessary to first determine the relationship between the reverse charging voltage and the speed in the SPO state, that is, to calibrate the reverse charging voltage value at different motor speeds in advance for subsequent comparison.

[0071] In a preferred embodiment, when the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs active short circuit or full shutdown protection on the motor in step S420, including:

[0072] S421: When the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs active short-circuit protection on the motor

[0073] As described above, when the current speed is in the mid-range, ASC and SPO can be selected to be executed. In this embodiment, the logic control of the protection measure is that when the current speed is in the mid-range, the selection process is skipped and the controller is directly selected to perform ASC protection on the motor, so as to save the intermediate program processing process.

[0074] On the other hand, S420 may include:

[0075] S421': When the current speed is greater than the first speed threshold and less than the second speed threshold, the motor controller performs full shutdown protection on the motor.

[0076] In this embodiment, the logic control of the protection measure is that when the current speed is in the middle range, the selection process is skipped and the controller is directly selected to perform SPO protection on the motor, which can also omit the intermediate program processing process.

[0077] S421”: When the current speed is greater than the first speed threshold and less than the second speed threshold, detecting the DC voltage of the motor, and comparing the DC voltage with the reverse charging voltage of the motor;

[0078] See also Figure 3 In another preferred embodiment, another judgment dimension is added to the logic control of the protection measures. Specifically, when the current speed is in the middle range, the DC voltage U real , the detected DC voltage U real It is understood that the motor reverse charging voltage is to the battery, and for the battery and other devices using the same power source, once the reverse charging voltage is too large, it may cause damage to other devices. Therefore, in this embodiment, the reverse charging voltage is used as the second judgment dimension.

[0079] S422”: When the DC voltage is less than or equal to the reverse charging voltage, the motor controller performs active short-circuit protection on the motor;

[0080] When the comparison result of the two is: the DC voltage is less than or equal to the reverse charging voltage, it means that if the SPO protection is executed, the reverse charging voltage generated by the motor is too large, which may cause impact on other devices. Then in step S422", the motor controller executes ASC protection on the motor and does not generate reverse charging voltage.

[0081] S423”: When the DC voltage is greater than or equal to the reverse charging voltage, the motor controller performs full shutdown protection on the motor.

[0082] On the other hand, when the comparison result of the two is: the DC voltage is greater than or equal to the reverse charging voltage, it means that if the SPO protection is executed, the motor back electromotive force will not actually reverse charge to the battery to raise the DC voltage, and will not cause impact on other devices. Then in step S423", the motor controller performs SPO protection on the motor, while ensuring that the braking torque is less than the safety torque, and at the same time avoiding damage to the motor electronic control by the ASC short-circuit current.

[0083] Furthermore, in the above judgment logic, when the current speed is greater than the first speed threshold and less than the second speed threshold, the step S421" of detecting the DC voltage of the motor and comparing the DC voltage with the reverse charging voltage of the motor also includes:

[0084] S420"-1: A voltage threshold is also set in the motor controller;

[0085] Considering that electrical appliances such as other electronic devices themselves have an acceptable voltage threshold, before using DC voltage as a judgment dimension, there is a premise, that is, the voltage threshold of the electrical appliance itself, which can be obtained from the electronic devices on the mainboard and stored in the motor controller.

[0086] S420"-2: Compare the reverse charging voltage of the motor with the voltage threshold;

[0087] When the comparison result of the current speed with the first speed threshold and the second speed threshold is: the current speed is greater than the first speed threshold and less than the second speed threshold, the back charging voltage of the motor will be detected in this embodiment. The detection method is to obtain the back electromotive force-speed curve of the motor in the SPO state in advance. After obtaining the current speed of the motor, the back electromotive force is queried and calculated in the back electromotive force-speed curve to obtain the corresponding back charging voltage through three-phase rectification, and compared with the voltage threshold.

[0088] S420"-3: When the reverse charging voltage is less than or equal to the voltage threshold, the motor controller performs full shutdown protection on the motor;

[0089] The comparison result of the above steps is: when the reverse charging voltage is less than or equal to the voltage threshold, it means that no matter what the relationship between the reverse charging voltage and the DC voltage is, the reverse charging voltage in the current state will not cause damage to the electrical appliance, and the motor controller can perform SPO protection on the motor.

[0090] S420"-4: When the reverse charging voltage is greater than the voltage threshold, detect the DC voltage of the motor and compare the DC voltage with the reverse charging voltage of the motor.

[0091] The comparison result of the above steps is: when the reverse charging voltage is greater than the voltage threshold, step S421" is executed to compare the DC voltage with the reverse charging voltage of the motor.

[0092] Through the above configuration, with the help of multi-layer comparison of voltage thresholds and DC voltages, the state of the motor can be controlled based on different usage requirements, such as meeting the normal use of electronic devices and saving energy by reverse charging of the motor.

[0093] In another preferred embodiment, the step S300 of determining the motor speeds corresponding to the first intersection point and the second intersection point as the first speed threshold and the second speed threshold includes:

[0094] S310: Obtain a first motor speed and a second motor speed corresponding to the first intersection and the second intersection;

[0095] After the first braking torque-speed curve and the second braking torque-speed curve are obtained through calibration, the x-axis values ​​of the first intersection and the second intersection obtained as described above correspond to the first motor speed and the second motor speed.

[0096] S320: Acquire a first speed interval before and after the speed of the first motor and a second speed interval before and after the speed of the second motor based on a speed redundancy ratio;

[0097] A speed redundancy ratio is preset in the motor controller, such as 5%, 10%, 15%, etc. The speed redundancy ratio will expand the values ​​of the first speed threshold and the second speed threshold. It is suggested that at the two specific speeds of the first motor speed and the second motor speed, the first speed interval and the second speed interval before and after the two data are calculated respectively, for example, the first motor speed*(1-speed redundancy ratio) is the lower limit of the first speed interval, and the first motor speed*(1+speed redundancy ratio) is the upper limit of the first speed interval.

[0098] S330: Define the first speed range and the second speed range as the first speed threshold and the second speed threshold

[0099] After obtaining the first speed range and the second speed range, they are defined as the first speed threshold and the second speed threshold respectively, so that the first speed threshold and the second speed threshold are expanded to range data, avoiding the ping-pong effect caused by repeated jumps of the ASC and SPO states when the current speed changes near the first speed threshold.

[0100] Furthermore, the circuit protection control method further includes the following steps:

[0101] S500: When the current speed jumps within or outside the first speed range, the motor controller is maintained to perform full shutdown protection on the motor;

[0102] S600: When the current speed jumps within or outside the second speed range, the motor controller is maintained to perform active short-circuit protection on the motor.

[0103] That is to say, if the current speed repeatedly changes when the first speed threshold and the second speed threshold are within the interval range, the ASC or SPO protection measures executed by the motor controller on the motor will be maintained even if the above judgment control logic is violated. Furthermore, a time threshold is set in the motor controller. When the motor controller executes ASC or SPO protection on the motor, it will be maintained for at least the time threshold, regardless of the current speed, braking torque or DC voltage changes within the time threshold, to prevent damage to the motor when the protection measures are repeatedly switched.

[0104] In other embodiments, other auxiliary parameters, such as rotor temperature, may be added to the calibration of the first braking torque-speed curve and the second braking torque-speed curve, so that the first braking torque-speed curve and the second braking torque-speed curve more accurately describe the condition of the motor. Specifically, the circuit protection control method also includes the following steps: based on the changes of the motor at different rotor temperatures, correcting the first braking torque-speed curve and the second braking torque-speed curve; determining the first speed threshold and the second speed threshold based on the rotor temperature. Or when referring to other parameters, it can be considered that when the DC voltage is very low, even if there is a reverse charging voltage, it will only cause a certain degree of voltage increase and will not cause damage to the device. Under the condition, SPO can also be selected to avoid damage to the motor electronic control by the ASC short-circuit current; when the device has a high pressure-bearing capacity, SPO can also be allowed to increase the voltage to a certain extent.

[0105] The present invention also discloses a circuit protection control system of a motor controller. The motor controller is connected to a motor to control the working state of the motor. The motor controller includes: a calibration module, which calibrates the relationship between the braking torque and the motor speed of the motor in the active short circuit and full-off state to form a first braking torque-speed curve and a second braking torque-speed curve and stores them, and the calibration module calibrates the safety torque curve of the motor in the braking torque-speed curve, so that the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve and the second braking torque-speed curve intersect at a second intersection. In addition, the relationship between the back electromotive force and the motor speed of the motor in the full-off state is formed into a back electromotive force -speed curve, and further calculation can form a back-electromotive force after three-phase bridge rectification-back charging voltage-speed curve and store it for subsequent comparison with the DC voltage; a processing module determines that the motor speeds corresponding to the first intersection and the second intersection are the first speed threshold and the second speed threshold; a control module detects the current speed of the motor and compares the current speed with the first speed threshold and / or the second speed threshold; when the current speed is less than or equal to the first speed threshold, the motor is fully shut down for protection; when the current speed is greater than the first speed threshold and less than the second speed threshold, the motor is actively short-circuited or fully shut down for protection; when the current speed is greater than or equal to the second speed threshold, the motor is actively short-circuited for protection.

[0106] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A circuit protection control method for a motor controller, characterized in that: The following steps are involved: Calibrate the relationship between the braking torque and the motor speed of a motor in an active short circuit and full shut-off state to form a first braking torque-speed curve and a second braking torque-speed curve; Calibrate the safety torque curve of the motor within the first braking torque-speed curve and the second braking torque-speed curve, so that the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve and the second braking torque-speed curve intersect at a second intersection; Determine that the motor speeds corresponding to the first intersection and the second intersection are a first speed threshold and a second speed threshold; Detecting a current rotation speed of the motor, and comparing the current rotation speed with the first rotation speed threshold and / or the second rotation speed threshold; When the current rotation speed is less than or equal to the first rotation speed threshold, the motor controller performs full shutdown protection on the motor; When the current speed is greater than a first speed threshold and less than a second speed threshold, the motor controller performs active short circuit or full shutdown protection on the motor; When the current rotation speed is greater than or equal to the second rotation speed threshold, the motor controller performs active short-circuit protection on the motor; When the current speed is greater than the first speed threshold and less than the second speed threshold, the step of the motor controller performing active short circuit or full shutdown protection on the motor includes: When the current speed is greater than a first speed threshold and less than a second speed threshold, detecting a DC voltage of the motor, and comparing the DC voltage with a reverse charging voltage of the motor at the current speed; When the DC voltage is less than or equal to the reverse charging voltage, the motor controller performs active short-circuit protection on the motor; When the DC voltage is greater than or equal to the reverse charging voltage, the motor controller performs full shutdown protection on the motor.

2. The circuit protection control method according to claim 1, characterized in that: When the current speed is greater than the first speed threshold and less than the second speed threshold, before the step of detecting the DC voltage of the motor and comparing the DC voltage with the reverse charging voltage of the motor, the method further includes: The motor controller is also provided with a voltage threshold; comparing the reverse charging voltage of the motor with the voltage threshold; When the reverse charging voltage is less than or equal to the voltage threshold, the motor controller performs full shut-down protection on the motor; When the reverse charging voltage is greater than the voltage threshold, the DC voltage of the motor is detected, and the DC voltage is compared with the reverse charging voltage of the motor.

3. The circuit protection control method according to claim 1, characterized in that: The step of determining that the motor speeds corresponding to the first intersection and the second intersection are the first speed threshold and the second speed threshold comprises: Acquire a first motor speed and a second motor speed corresponding to the first intersection point and the second intersection point; Acquire a first speed interval before and after the speed of the first motor and a second speed interval before and after the speed of the second motor based on a speed redundancy ratio; The first speed interval and the second speed interval are defined as a first speed threshold and a second speed threshold.

4. The circuit protection control method according to claim 3, characterized in that: The following steps are also included: When the current speed jumps within or outside the first speed range, maintaining the motor controller to perform full shutdown protection on the motor; When the current speed changes within or outside the second speed range, the motor controller is maintained to perform active short-circuit protection on the motor.

5. The circuit protection control method according to claim 4, characterized in that: The motor controller is provided with a time threshold. When the motor controller performs full shutdown protection or active short circuit protection on the motor, the time threshold will be maintained at least.

6. The circuit protection control method according to claim 1, characterized in that: The following steps are also included: Based on the change of the motor at different rotor temperatures, modifying the first braking torque-speed curve and the second braking torque-speed curve; The first speed threshold value and the second speed threshold value are determined based on the rotor temperature.

7. A circuit protection control system for a motor controller, wherein the motor controller is connected to a motor to control the working state of the motor, characterized in that: The motor controller comprises: a calibration module, calibrating the relationship between the braking torque and the motor speed of the motor in the active short-circuit and full-off states to form a first braking torque-speed curve and a second braking torque-speed curve and storing them, and the calibration module calibrates the safety torque curve of the motor within the first braking torque-speed curve and the second braking torque-speed curve, so that the safety torque curve intersects with the first braking torque-speed curve at a first intersection, and the first braking torque-speed curve and the second braking torque-speed curve intersect at a second intersection; A processing module, determining that the motor speeds corresponding to the first intersection and the second intersection are a first speed threshold and a second speed threshold; A control module detects a current speed of the motor and compares the current speed with the first speed threshold and / or the second speed threshold; when the current speed is less than or equal to the first speed threshold, performs full-off protection on the motor; when the current speed is greater than the first speed threshold and less than the second speed threshold, performs active short-circuit or full-off protection on the motor; when the current speed is greater than or equal to the second speed threshold, performs active short-circuit protection on the motor; When the current speed is greater than the first speed threshold and less than the second speed threshold, the step of the motor controller performing active short circuit or full shutdown protection on the motor includes: When the current speed is greater than a first speed threshold and less than a second speed threshold, detecting a DC voltage of the motor, and comparing the DC voltage with a reverse charging voltage of the motor at the current speed; When the DC voltage is less than or equal to the reverse charging voltage, the motor controller performs active short-circuit protection on the motor; When the DC voltage is greater than or equal to the reverse charging voltage, the motor controller performs full shutdown protection on the motor.

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