A method for detecting motor faults

Abstract

The present invention provides a method for detecting motor faults, comprising the following steps: obtaining calibrated current data for a motor winding, the calibrated current data including multiple sets of correspondences between calibrated current and time at different motor speeds; sending a detection pulse to the motor winding; detecting sampled currents of the motor windings at preset time intervals to obtain sampled current data, and determining the motor speed corresponding to the sampled current data; determining the calibrated current data corresponding to the sampled current data based on the motor speed corresponding to the sampled current data; determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibrated current data corresponding to the sampled current data; and determining that the motor is fault-free if the sampled current included in the sampled current data is within the current interval. This method can achieve high detection efficiency without disassembling the motor, and provides more accurate detection results.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a method for detecting motor faults. Background Art

[0002] Motors can experience a variety of faults during use, including short circuits between motor winding turns, severe carbon brush wear, or rusted motor terminals. A short circuit between motor winding turns generates a large current, rapidly heating the coil and exacerbating damage to the motor circuit. It can also reduce output power or magnetic field strength.

[0003] Currently, established offline testing methods for detecting inter-turn short circuits in motor windings include DC voltage drop, DC resistance, AC impedance, and power loss. However, these methods typically require the motor to be removed from the product for testing, resulting in low efficiency. Furthermore, these methods are performed while the motor is stationary, failing to consider the varying effects of centrifugal force, magnetic field, and other parameters on inter-turn short circuits at different motor speeds, leading to inaccurate test results. Summary of the Invention

[0004] The present invention provides a method for detecting motor faults, so as to solve the technical problems of low efficiency and inaccurate detection results in existing methods for detecting motor faults.

[0005] To solve the above technical problems, the present invention provides a method for detecting motor faults, comprising the following steps:

[0006] Acquire calibration current data of the motor winding, wherein the calibration current data includes a plurality of sets of corresponding relationships between calibration current and time at different motor speeds;

[0007] sending a detection pulse to the motor winding;

[0008] Detecting a sampled current of the motor winding at a preset time interval to obtain sampled current data, and determining a motor speed corresponding to the sampled current data, wherein the sampled current data includes a corresponding relationship between the sampled current and time;

[0009] Determining calibration current data corresponding to the sampled current data according to the motor speed corresponding to the sampled current data;

[0010] According to the current interval corresponding to the calibration current data corresponding to the sampled current data, it is determined whether the sampled current included in the sampled current data is within the current interval; if the sampled current included in the sampled current data is within the current interval, it is determined that the motor is not faulty; if the sampled current included in the sampled current data is not within the current interval, it is determined that the motor is faulty.

[0011] Optionally, the step of obtaining the calibrated current data of the motor winding specifically includes the following steps:

[0012] S11, electrically connecting the motor controller to the motor winding, and communicating with the motor controller to the host computer;

[0013] S12, set the motor speed to 0;

[0014] S13, using the host computer to send a calibration single pulse instruction to the motor controller;

[0015] S14, the motor controller includes a microcontroller unit and a power unit, the power unit includes a drive circuit, when the microcontroller unit receives the single pulse instruction, the microcontroller unit sends a first calibration pulse to the drive circuit, the drive circuit sends a second calibration pulse to the motor winding according to the first calibration pulse, the voltage of the second calibration pulse is greater than the voltage of the first calibration pulse;

[0016] S15. Detecting the calibrated current of the motor winding at preset time intervals, and determining a corresponding relationship between the calibrated current and time at each time point;

[0017] S16, using the dragging device to make the motor speed reach a first preset speed;

[0018] S17, repeating S13-S15, determining the corresponding relationship between the calibration current and time at each time point when the motor speed is at the first preset speed;

[0019] S18. Using the same principle as S16-S17, determine the corresponding relationship between the calibrated current and time at each time point when the motor speed is at a plurality of different preset speeds.

[0020] Optionally, the maximum speed among the multiple different preset speeds is equal to the rated speed of the motor; 0, the first preset speed, and the multiple different preset speeds are distributed in an arithmetic progression.

[0021] Optionally, the step of determining the motor speed corresponding to the sampled current data specifically includes:

[0022] The motor speed is collected while detecting the sampling current of the motor winding, and the average value of multiple motor speeds detected within the time period of the detection pulse is used as the motor speed corresponding to the sampling current data.

[0023] Optionally, the calibration current data includes a plurality of calibration current curves, each calibration speed corresponding to a calibration current curve; and the step of determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data specifically includes the following steps:

[0024] S51, determining whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data; if the motor speed corresponding to the sampled current data is equal to the first calibrated speed corresponding to the calibrated current data, executing S52; if the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, executing S53;

[0025] S52, determining whether a sampled current curve corresponding to the sampled current data is within a preset percentage range of a calibration current curve corresponding to the first calibration speed; if the sampled current curve is above the preset percentage range of the calibration current curve corresponding to the first calibration speed, determining that an inter-turn short circuit occurs in the motor winding; if the sampled current curve is within the preset percentage range of the calibration current curve corresponding to the calibration motor speed, determining that the motor is normal;

[0026] S53. Determine a second calibrated speed and a third calibrated speed adjacent to the motor speed corresponding to the sampled current data, wherein the second calibrated speed is less than the motor speed corresponding to the sampled current data and less than the third calibrated speed; determine whether a sampled current curve corresponding to the sampled current data is within the range of a second calibrated current curve corresponding to the second calibrated speed and a third calibrated current curve corresponding to the third calibrated speed; if the sampled current curve is above the second calibrated current curve and the third calibrated current curve, determine that the motor winding is short-circuited; if the sampled current curve is between the second calibrated current curve and the third calibrated current curve, determine that the motor is normal.

[0027] Optionally, the motor is a brushed motor, and step S52 further includes: if the sampled current curve is below a preset percentage range of the calibration current curve corresponding to the first calibration speed, determining that the carbon brushes of the motor are excessively worn, the motor terminals are corroded, or the screws fixing the motor terminals are loose;

[0028] Step S53 further includes: if the sampling current curve is below the second calibration current curve and the third calibration current curve, determining that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose.

[0029] Optionally, the calibration circuit data includes a correspondence between multiple discrete calibration currents and multiple discrete time points, and each calibration speed corresponds to multiple discrete calibration currents and multiple discrete time points; the step of determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data specifically includes the following steps:

[0030] S501, determining whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data; if the motor speed corresponding to the sampled current data is equal to a fourth calibrated speed corresponding to the calibrated current data, executing S502; if the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, executing S503;

[0031] S502: Determine whether, at the same time point, the sampled current corresponding to the sampled current data is within a preset percentage range of the calibration current corresponding to the fourth calibration speed; if the sampled current is above the preset percentage range of the calibration current corresponding to the fourth calibration speed, determine that an inter-turn short circuit occurs in the motor winding; if the sampled current is within the preset percentage range of the calibration current corresponding to the fourth calibration speed, determine that the motor is normal;

[0032] S503. Determine a fifth calibrated speed and a sixth calibrated speed that are adjacent to the motor speed corresponding to the sampled current data, wherein the fifth calibrated speed is less than the motor speed corresponding to the sampled current data and is less than the sixth calibrated speed; determine whether, at the same time point, the sampled current corresponding to the sampled current data is between the fifth calibrated current corresponding to the fifth calibrated speed and the sixth calibrated current corresponding to the sixth calibrated speed; if the sampled current is above the fifth calibrated current and the sixth calibrated current, determine that the motor winding turns are short-circuited; if the sampled current is between the fifth calibrated current and the sixth calibrated current, determine that the motor is normal.

[0033] Optionally, the motor is a brushed motor, and step S502 further includes: if the sampled current is below a preset percentage range of a calibration current corresponding to the fourth calibration speed, determining that the carbon brushes of the motor are excessively worn, the motor terminals are corroded, or the screws fixing the motor terminals are loose;

[0034] Step S503 further includes: if the sampled current is lower than the fifth calibration current and the sixth calibration current, determining that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose.

[0035] Optionally, the step of sending a detection pulse to the motor winding specifically includes: sending a detection pulse to the motor winding when the motor is powered on and started.

[0036] Optionally, the step of sending a detection pulse to the motor winding specifically includes: sending a detection pulse to the motor winding after the motor is powered on and started, the motor speed is greater than 0, and the motor controller has not sent a control signal to the motor winding for a period of time exceeding a preset time. The present invention provides a method for detecting motor faults, which can determine whether the motor is faulty based on the calibrated current data and sampled current data of the motor winding. When the equipment containing the motor leaves the factory, it can determine whether the motor is faulty without disassembling the motor, and the detection efficiency is high. This method can detect motor faults while the motor is rotating, and uses the motor speed as a judgment condition for determining motor faults, resulting in more accurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of a method for detecting motor faults provided by one embodiment of the present invention.

[0038] Figure 2 This is a calibration current curve provided by an embodiment of the present invention under the second calibration pulse when the motor speed is 0 rpm, 200 rpm, and rated speed. DETAILED DESCRIPTION

[0039] To make the objectives, advantages, and features of the present invention more clearly apparent, a method for detecting motor faults according to the present invention is further described below in detail with reference to the accompanying drawings. It should be noted that the accompanying drawings are highly simplified and not to exact scale, and are only used to facilitate and clearly illustrate the objectives of the embodiments of the present invention.

[0040] In the description of the present invention, qualifiers such as "first" and "second" are added for convenience of description and reference and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features qualified with qualifiers such as "first" and "second" may explicitly or implicitly include one or more of such features.

[0041] like Figure 1 As shown, this embodiment provides a method for detecting motor faults. The execution subject of the method may be a motor controller, and the method includes the following steps:

[0042] S1. Acquire calibration current data of the motor winding, wherein the calibration current data includes a plurality of sets of corresponding relationships between calibration current and time at different motor speeds.

[0043] After the motor is assembled, the current of each motor can be calibrated, or the current of the sampled motors can be calibrated after sampling. The method for detecting motor faults provided by the present invention is applicable to brushed motors and brushless motors. In the specific implementation, the brushed motor is mainly used as the implementation object for specific description. The calibration current data can be in the form of a table or an image, and the calibration current data is the correspondence between the calibration current and time. The calibration circuit data can be stored in the motor controller. The same type of motor can directly use the calibration current data obtained by the previous calibration, that is, the calibration current data obtained by the previous calibration is directly stored in the motor controller of the same type, and the calibration current data is used as the reference current. In theory, the more calibration current data the calibration current data includes, the more accurate the detection result is. The correspondence between the calibration current and time at multiple groups of different motor speeds refers to the correspondence between the current and time obtained by current calibration of the motor at different motor speeds.

[0044] S2. Sending a detection pulse to the motor winding.

[0045] Optionally, when the motor winding does not receive other control signals, that is, when the current of the motor winding is zero, a detection pulse is sent to the motor winding. When the motor winding does not receive other control signals, it means that the motor controller does not control the rotation or braking of the motor, that is, the motor controller does not send a rotation signal or a braking signal to the motor winding. For example, when the motor controller is powered on and started, when the aerial work platform containing the motor is not powered on and moves under the push of an external force, or when other equipment containing the motor is free to slide when not powered on, the motor winding does not receive other control signals. The detection pulse is sent to the motor winding only when the motor winding does not receive other control signals in order to prevent signal interference when more than two signals are sent at the same time. The detection pulse can be sent to the motor winding by the motor controller, and the use of the motor controller originally configured for the motor can reduce the cost of the product. In other embodiments, a new controller can also be added to implement a method for detecting motor failure provided by the present invention.

[0046] In other embodiments, current may flow through the motor windings during the calibration process, as long as the currents in the motor windings during the detection process and the calibration process are equal or very close. In this case, a detection pulse may be sent to the motor windings when the current in the motor windings is equal to or very close to the current during the calibration process.

[0047] S3. Detecting the sampled current of the motor winding at preset time intervals to obtain sampled current data, and determining the motor speed corresponding to the sampled current data, wherein the sampled current data includes a corresponding relationship between the sampled current and time.

[0048] While the detection pulse is being transmitted, the current in the motor winding can be sampled once every 7 μs, ultimately forming two-dimensional data of current (i.e., sampling current) versus time. When current data is used, the data format of the sampling current is the same as the calibration current data, which can be in tabular or graphical form. For ease of description, the detected current is divided into calibration current and sampling current. The calibration current is the current detected during calibration, while the sampling current is the current detected in real time when a motor fault is detected.

[0049] S4. Determine calibration current data corresponding to the sampled current data according to the motor speed corresponding to the sampled current data.

[0050] It is possible to first determine whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data. If the motor speed corresponding to the sampled current data is equal to a certain calibrated speed corresponding to the calibrated current data, then the calibrated current data corresponding to the certain calibrated speed is the calibrated current data corresponding to the sampled current data. If the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, then the calibrated current data corresponding to two adjacent calibrated speeds of the motor speed corresponding to the sampled current data can be the calibrated current data corresponding to the sampled current data. The calibrated speed is the speed of the motor during current calibration.

[0051] S5. Determine whether the sampled current contained in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data; if the sampled current contained in the sampled current data is within the current interval, determine that the motor is not faulty; if the sampled current contained in the sampled current data is not within the current interval, determine that the motor is faulty. When both the calibration current data and the sampled current data are in graphical form, determine whether the motor is faulty based on whether the curve corresponding to the sampled current data is within the range of two curves corresponding to the calibration current data; if so, determine that the motor is faulty; if not, determine that the motor is faulty. When both the calibration current data and the sampled current data are in tabular form, determine whether the motor is faulty based on whether the sampled current corresponding to the sampled current data is within the two discrete calibration current ranges corresponding to the calibration current data at the same time point; if so, determine that the motor is faulty; if not, determine that the motor is faulty.

[0052] A method for detecting motor faults provided in this embodiment can determine whether the motor has a fault based on the calibrated current data and sampled current data of the motor winding. When the equipment containing the motor leaves the factory, it can be determined whether the motor has a fault without disassembling the motor, and the detection efficiency is high. This method can detect motor faults while the motor is rotating, and uses the motor speed as a judgment condition for determining motor faults, so the detection result is more accurate.

[0053] Optionally, the step of obtaining the calibrated current data of the motor winding specifically includes the following steps:

[0054] S11, electrically connecting the motor controller to the motor windings, and establishing a communication connection between the motor controller and a host computer, wherein the host computer can be set in a computer to facilitate operation of the host computer.

[0055] S12: Set the motor speed to 0.

[0056] S13, using the host computer to send a calibration single pulse instruction to the motor controller.

[0057] S14. The motor controller includes a microcontroller unit and a power unit. The power unit includes a drive circuit. When the microcontroller unit receives the single pulse instruction, the microcontroller unit sends a first calibration pulse to the drive circuit. The drive circuit sends a second calibration pulse to the motor winding according to the first calibration pulse. The voltage of the second calibration pulse is greater than the voltage of the first calibration pulse. The relationship between the first calibration pulse and the second calibration pulse is that a low voltage is used to control a high voltage. The first calibration pulse is a low voltage, and the second calibration pulse is a high voltage compared to the first calibration pulse. The first calibration pulse can be a low-voltage pulse of about 70us. The pulse time of the second calibration pulse is equal to the pulse time of the first pulse. The pulse time is the duration of the pulse. The voltage of the second calibration pulse is greater than the voltage of the first calibration pulse. In this way, a larger current can be detected, which is consistent with the current size when the motor is working normally. The second calibration pulse can refer to Figure 2 As shown in the pulse curve below the middle curve 3.

[0058] S15. Detect the calibrated current of the motor winding at preset time intervals and determine the corresponding relationship between the calibrated current and time at each time point. Starting from sending the first calibration pulse, the motor controller's onboard motor winding current detection module samples the current in the motor winding once every 7 μs, ultimately forming two-dimensional data of current and time, and storing this data in the brushed motor controller's storage medium.

[0059] S16: Using a dragging device to make the motor speed reach a first preset speed. The motor can be dragged by a motor test bench to make the motor reach different preset speeds.

[0060] S17, repeating S13-S15, determining the corresponding relationship between the calibration current and time at each time point when the motor speed is at the first preset speed;

[0061] S18. Using the same principle as S16-S17, determine the corresponding relationship between the calibrated current and time at each time point when the motor speed is at a plurality of different preset speeds.

[0062] This embodiment provides a method for calibrating the current in a motor winding. Ideally, for the same second calibration pulse, the current in the motor winding is maximum when the motor speed is zero. As the motor speed increases, the current in the motor winding decreases due to the back electromotive force in the motor winding. However, actual measurement results may have some deviation. Using actual measurement results as calibration current data can make the detection results more accurate.

[0063] Optionally, after step S18, the following steps are further included:

[0064] S19. Compare the calibrated current at each time point with the pre-stored current threshold range. If the calibrated current at each time point is within the current threshold range, the calibrated current data is determined to be correct; if there is at least one time point where the calibrated current is not within the current threshold range, the calibrated current data is determined to be incorrect, and S12-S18 are re-executed.

[0065] The pre-stored current threshold range is the winding current of the motor winding under normal circumstances, which is pre-estimated based on the second calibration pulse and the resistance of the motor winding. If the calibration current detected during the calibration process is greater than the maximum value of the current threshold range, it means that the motor winding turns have been short-circuited during the calibration and need to be recalibrated. If the calibration current detected during the calibration process is less than the minimum value of the current threshold range, it means that the motor has serious carbon brush wear, or rust on the motor terminals, or loose screws and other poor contact problems during the calibration, and recalibration is also required. If the calibration current at each time point is within the current threshold range, it is determined that the calibration current data is correct and no recalibration is required. The calibration current data obtained in this calibration can be used as a reference current. The step of reviewing the calibration current data provided in this embodiment can prevent the calibration current data from being inaccurate and affecting the subsequent motor fault detection.

[0066] Optionally, the maximum speed among the multiple different preset speeds is equal to the rated speed of the motor; 0, the first preset speed, and the multiple different preset speeds are distributed in an arithmetic progression.

[0067] In actual use, the current calibration of the motor rotor speeds of 0rpm, 200rpm, 400rpm, 600rpm, ..., rated speed can be carried out in sequence, and finally a set of curve clusters are obtained. The theoretical calibration current curve is as follows Figure 2 As shown, Curves 1, 2, and 3 represent the calibration current curves for motor speeds of 0 rpm, 200 rpm, and rated speed, respectively. Curve 2 lies between Curves 1 and 3. That is, at the same point in time, Curve 1 has the highest calibration current, while Curve 3 has the lowest. However, in practice, due to differences in motor assembly and materials, Curve 2 may lie below Curve 3. While calibration current curves for other speeds are theoretically also between Curves 1 and 3, this is not always the case in practice. Therefore, calibrating multiple sets of calibration current curves can improve detection effectiveness and reliability. Figure 2 Curve 1, curve 2, and curve 3 are represented by line segments, which are actually curves drawn through the corresponding relationship between multiple calibration currents and time points.

[0068] This embodiment provides a method for detecting motor faults, which performs current calibration on detection pulses of different speeds, taking into account the data discreteness caused by differences in circuit parameters of individual products, greatly improving the effectiveness and reliability of this method and providing a reliable data source for determining motor faults.

[0069] Optionally, the step of determining the motor speed corresponding to the sampled current data specifically includes:

[0070] While detecting the sampled current of the motor winding, the motor speed is collected, and the average of the multiple motor speeds detected during the duration of the detection pulse is used as the motor speed corresponding to the sampled current data. The motor speed obtained in this manner can better reflect the motor speed during the sampling process of the sampled current data. In other embodiments, the motor speed at the beginning of current sampling or at the end of current sampling can also be used as the motor speed corresponding to the sampled current.

[0071] Optionally, the calibration current data includes a plurality of calibration current curves, each calibration speed corresponding to a calibration current curve; and the step of determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data specifically includes the following steps:

[0072] S51. Determine whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data. If the motor speed corresponding to the sampled current data is equal to the first calibrated speed corresponding to the calibrated current data, execute S52; if the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, execute S53.

[0073] S52. Determine whether the sampled current curve corresponding to the sampled current data is within a preset percentage range of the calibration current curve corresponding to the first calibration speed; if the sampled current curve is above the preset percentage range of the calibration current curve corresponding to the first calibration speed, determine that the motor winding has a short circuit; if the sampled current curve is within a preset percentage range of the calibration current curve corresponding to the calibration motor speed, determine that the motor is normal. The preset percentage can be approximately ±10%. Figure 2 As shown, if the motor speed corresponding to the sampled current data is equal to the motor speed corresponding to curve 2 (i.e., the calibrated speed), curve 2 can be moved up and down by 10% as a reference range. If the sampled current curve is above curve 2 after moving up by 10%, it is determined that the motor winding turns are short-circuited; if the sampled current curve is within the range after curve 2 moves up and down by 10%, it is determined that the motor is normal.

[0074] S53, determining a second calibrated speed and a third calibrated speed adjacent to the motor speed corresponding to the sampled current data, wherein the second calibrated speed < the motor speed corresponding to the sampled current data < the third calibrated speed; judging whether the sampled current curve corresponding to the sampled current data is within the range of the second calibrated current curve corresponding to the second calibrated speed and the third calibrated current curve corresponding to the third calibrated speed; if the sampled current curve is above the second calibrated current curve and the third calibrated current curve, judging that the motor winding is short-circuited; if the sampled current curve is between the second calibrated current curve and the third calibrated current curve, judging that the motor is normal. Reference Figure 2 As shown, if the motor speed corresponding to the sampled current data is not equal to the calibrated speed corresponding to any curve, and the motor speed corresponding to the sampled current data is between the calibrated speed corresponding to curve 1 and the calibrated speed corresponding to curve 2, then curve 1 can be used as the second calibrated current and curve 2 can be used as the third calibrated current. The method for detecting motor faults provided in this embodiment can quickly and intuitively determine whether there is a short circuit between motor winding turns, thereby improving detection efficiency.

[0075] Optionally, the motor is a brushed motor, and step S52 further includes: if the sampled current curve is below a preset percentage range of the calibration current curve corresponding to the first calibration speed, determining that the carbon brushes of the motor are excessively worn, the motor terminals are corroded, or the screws fixing the motor terminals are loose;

[0076] Step S53 further includes: if the sampling current curve is below the second calibration current curve and the third calibration current curve, determining that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose.

[0077] The method for detecting motor faults provided in this embodiment can also detect the conditions of the motor's carbon brushes, motor terminals, and screws fixing the motor terminals.

[0078] Optionally, the calibration circuit data includes a correspondence between multiple discrete calibration currents and multiple discrete time points, and each calibration speed corresponds to multiple discrete calibration currents and multiple discrete time points; the step of determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data specifically includes the following steps:

[0079] S501. Determine whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data. If the motor speed corresponding to the sampled current data is equal to the fourth calibrated speed corresponding to the calibrated current data, execute S502; if the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, execute S503.

[0080] S502: Determine whether the sampled current corresponding to the sampled current data is within a preset percentage range of the calibration current corresponding to the fourth calibration speed at the same time point; if the sampled current is above the preset percentage range of the calibration current corresponding to the fourth calibration speed, determine that the motor winding has a short circuit; if the sampled current is within the preset percentage range of the calibration current corresponding to the fourth calibration speed, determine that the motor is normal. Assume that the calibration current data includes a one-to-one correspondence between 10 current values ​​and 10 time points when the motor speed is 200 rpm; the motor speed corresponding to the sampled current is also 200 rpm, and 10 sampled current values ​​are collected at the same time point, then the sampled current at the same time point can be compared with the preset percentage of the calibration current to determine whether the motor has a fault.

[0081] S503. Determine a fifth calibrated speed and a sixth calibrated speed that are adjacent to the motor speed corresponding to the sampled current data, wherein the fifth calibrated speed is less than the motor speed corresponding to the sampled current data and is less than the sixth calibrated speed; determine whether, at the same time point, the sampled current corresponding to the sampled current data is between the fifth calibrated current corresponding to the fifth calibrated speed and the sixth calibrated current corresponding to the sixth calibrated speed; if the sampled current is above the fifth calibrated current and the sixth calibrated current, determine that the motor winding turns are short-circuited; if the sampled current is between the fifth calibrated current and the sixth calibrated current, determine that the motor is normal.

[0082] This embodiment provides a method for detecting motor faults that can quickly determine whether a short circuit exists between motor winding turns, improving detection efficiency. For example, at the same time, the calibrated currents corresponding to the fifth and sixth calibrated speeds are 21A and 26A, respectively. A sampled current of 40A indicates a short circuit between motor winding turns; a sampled current of 23A indicates a normal motor condition.

[0083] Optionally, the motor is a brushed motor, and step S502 also includes: if the sampling current is below the preset percentage range of the calibration current corresponding to the fourth calibration speed, it is determined that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose; step S503 also includes: if the sampling current is below the fifth calibration current and the sixth calibration current, it is determined that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose.

[0084] The method for detecting motor faults provided in this embodiment can also detect the conditions of the motor's carbon brushes, motor terminals, and screws fixing the motor terminals.

[0085] Optionally, the step of sending a detection pulse to the motor winding specifically includes sending a detection pulse to the motor winding when the motor is powered on. When the motor is powered on, the motor controller has not yet controlled the motor speed. At this time, the motor controller can send the detection pulse to the motor winding to detect whether the motor is faulty when the motor is powered on.

[0086] Optionally, the step of sending a detection pulse to the motor winding specifically includes sending a detection pulse to the motor winding after the motor is powered on and the motor speed is greater than 0 and the motor controller has not sent a control signal to the motor winding for a period exceeding a preset time. After the motor controller has not sent a control signal to the motor winding for a period exceeding the preset time, the motor controller is in an idle state. At this time, if the device including the motor is free-coasting downhill, the motor controller can send a detection pulse to the motor winding to detect whether the motor is faulty while it is rotating.

[0087] Optionally, the pulse time of the second calibration pulse is 20-500 μs, and the voltage range of the second calibration pulse is 15-100 V.

[0088] The second calibration pulse provided in this embodiment is easy to obtain and does not cause high voltage damage to the motor of the existing aerial work platform.

[0089] To sum up, the present invention provides a method for detecting motor faults, which can determine whether the motor is faulty based on the calibrated current data and sampled current data of the motor winding. When the equipment containing the motor leaves the factory, it can be determined whether the motor is faulty without disassembling the motor, and the detection efficiency is high. This method can perform fault detection on the motor while the motor is rotating, and the motor speed is used as a judgment condition for judging motor faults, and the detection result is more accurate.

[0090] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in this field based on the above disclosure are within the scope of protection of the present invention.

Claims

1. A method for detecting motor failure, characterized in that: The following steps are involved: Acquire calibration current data of the motor winding, wherein the calibration current data includes a plurality of sets of corresponding relationships between calibration current and time at different motor speeds; sending a detection pulse to the motor winding; Detecting a sampled current of the motor winding at a preset time interval to obtain sampled current data, and determining a motor speed corresponding to the sampled current data, wherein the sampled current data includes a corresponding relationship between the sampled current and time; Determining calibration current data corresponding to the sampled current data according to the motor speed corresponding to the sampled current data; According to the current interval corresponding to the calibration current data corresponding to the sampled current data, determining whether the sampled current included in the sampled current data is within the current interval; If the sampled current included in the sampled current data is within the current interval, it is determined that the motor has no fault; if the sampled current included in the sampled current data is not within the current interval, it is determined that the motor has a fault; The step of obtaining the calibrated current data of the motor winding specifically includes the following steps: S11, electrically connecting the motor controller to the motor winding, and communicating with the motor controller to the host computer; S12, set the motor speed to 0; S13, using the host computer to send a calibration single pulse instruction to the motor controller; S14, the motor controller includes a microcontroller unit and a power unit, the power unit includes a drive circuit, when the microcontroller unit receives the single pulse instruction, the microcontroller unit sends a first calibration pulse to the drive circuit, the drive circuit sends a second calibration pulse to the motor winding according to the first calibration pulse, the voltage of the second calibration pulse is greater than the voltage of the first calibration pulse; S15. Detecting the calibrated current of the motor winding at preset time intervals, and determining a corresponding relationship between the calibrated current and time at each time point; S16, using the dragging device to make the motor speed reach a first preset speed; S17, repeating S13-S15, determining the corresponding relationship between the calibration current and time at each time point when the motor speed is at the first preset speed; S18. Using the same principle as S16-S17, determine the corresponding relationship between the calibrated current and time at each time point when the motor speed is at a plurality of different preset speeds.

2. A method for detecting motor failure according to claim 1, characterized in that: The maximum speed among the multiple different preset speeds is equal to the rated speed of the motor; the motor speed is 0, the first preset speed, and the multiple different preset speeds are distributed in an arithmetic progression.

3. A method for detecting motor failure according to claim 1, characterized in that: The step of determining the motor speed corresponding to the sampled current data specifically includes: The motor speed is collected while detecting the sampling current of the motor winding, and the average value of multiple motor speeds detected within the time period of the detection pulse is used as the motor speed corresponding to the sampling current data.

4. A method for detecting motor failure according to claim 1, characterized in that: The calibration current data includes a plurality of calibration current curves, each calibration speed corresponding to a calibration current curve; the step of determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data specifically includes the following steps: S51, determining whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data; if the motor speed corresponding to the sampled current data is equal to the first calibrated speed corresponding to the calibrated current data, executing S52; if the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, executing S53; S52, determining whether a sampled current curve corresponding to the sampled current data is within a preset percentage range of a calibration current curve corresponding to the first calibration speed; if the sampled current curve is above the preset percentage range of the calibration current curve corresponding to the first calibration speed, determining that an inter-turn short circuit occurs in the motor winding; if the sampled current curve is within the preset percentage range of the calibration current curve corresponding to the calibration motor speed, determining that the motor is normal; S53. Determine a second calibrated speed and a third calibrated speed adjacent to the motor speed corresponding to the sampled current data, wherein the second calibrated speed is less than the motor speed corresponding to the sampled current data and less than the third calibrated speed; determine whether a sampled current curve corresponding to the sampled current data is within the range of a second calibrated current curve corresponding to the second calibrated speed and a third calibrated current curve corresponding to the third calibrated speed; if the sampled current curve is above the second calibrated current curve and the third calibrated current curve, determine that the motor winding is short-circuited; if the sampled current curve is between the second calibrated current curve and the third calibrated current curve, determine that the motor is normal.

5. A method for detecting motor failure according to claim 4, characterized in that: The motor is a brushed motor, and step S52 further includes: if the sampled current curve is below a preset percentage range of the calibration current curve corresponding to the first calibration speed, determining that the carbon brushes of the motor are excessively worn, the motor terminals are corroded, or the screws fixing the motor terminals are loose; Step S53 further includes: if the sampling current curve is below the second calibration current curve and the third calibration current curve, determining that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose.

6. A method for detecting motor failure according to claim 1, characterized in that: The calibration circuit data includes a correspondence between a plurality of discrete calibration currents and a plurality of discrete time points, and each calibration speed corresponds to a plurality of discrete calibration currents and a plurality of discrete time points; the step of determining whether the sampled current included in the sampled current data is within the current interval corresponding to the calibration current data corresponding to the sampled current data specifically includes the following steps: S501, determining whether the motor speed corresponding to the sampled current data is equal to any calibrated speed corresponding to the calibrated current data; if the motor speed corresponding to the sampled current data is equal to a fourth calibrated speed corresponding to the calibrated current data, executing S502; if the motor speed corresponding to the sampled current data is not equal to any calibrated speed corresponding to the calibrated current data, executing S503; S502: Determine whether, at the same time point, the sampled current corresponding to the sampled current data is within a preset percentage range of the calibration current corresponding to the fourth calibration speed; if the sampled current is above the preset percentage range of the calibration current corresponding to the fourth calibration speed, determine that an inter-turn short circuit occurs in the motor winding; if the sampled current is within the preset percentage range of the calibration current corresponding to the fourth calibration speed, determine that the motor is normal; S503. Determine a fifth calibrated speed and a sixth calibrated speed that are adjacent to the motor speed corresponding to the sampled current data, wherein the fifth calibrated speed is less than the motor speed corresponding to the sampled current data and is less than the sixth calibrated speed; determine whether, at the same time point, the sampled current corresponding to the sampled current data is between the fifth calibrated current corresponding to the fifth calibrated speed and the sixth calibrated current corresponding to the sixth calibrated speed; if the sampled current is above the fifth calibrated current and the sixth calibrated current, determine that the motor winding turns are short-circuited; if the sampled current is between the fifth calibrated current and the sixth calibrated current, determine that the motor is normal.

7. A method for detecting motor failure according to claim 6, characterized in that: The motor is a brushed motor, and step S502 also includes: if the sampled current is below a preset percentage range of the calibration current corresponding to the fourth calibration speed, it is determined that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose; step S503 also includes: if the sampled current is below the fifth calibration current and the sixth calibration current, it is determined that the carbon brushes of the motor are worn beyond the standard, the motor terminals are corroded, or the screws fixing the motor terminals are loose.

8. A method for detecting motor failure according to claim 1, characterized in that: The step of sending a detection pulse to the motor winding specifically includes: sending a detection pulse to the motor winding when the motor is powered on and started.

9. A method for detecting motor failure according to claim 1, characterized in that: The step of sending a detection pulse to the motor winding specifically includes: sending a detection pulse to the motor winding after the motor is powered on and started, the motor speed is greater than 0, and the motor controller does not send a control signal to the motor winding for more than a preset time.

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