Motor stall detection system and method

Abstract

The invention discloses a motor stall detection system and method, and relates to the technical field of motor control, and the system comprises a preset register group which is used for storing a preset number of continuous electrical half cycles; wherein the preset number of continuous electrical half cycles comprise the latest electrical half cycle; the calculation circuit is connected with the preset register block and is used for calculating an electrical cycle detection value according to all electrical half cycles in the preset register block; the stall fault judgment circuit is connected with the calculation circuit and is used for determining that the operation condition of the motor to be detected is a motor stall state when the electrical cycle detection value is greater than or equal to a stall threshold value; according to the method, the counter electromotive force between the rising current quadrant and the falling current quadrant can be compared through electrical cycle detection, so that the stall state of the motor is rapidly and conveniently detected, and the detection cost and the operation complexity are reduced; and the motor stall detection can be realized by adopting a digital circuit, the occupied area is small, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a motor stall detection system and method. Background Technology

[0002] Currently, the following relationship is known between motor current, back EMF, and torque load: When unloaded (i.e., torque load is 0), the back EMF and motor current have a 90° phase difference; as the torque load gradually increases, the phase difference between the two decreases; when fully loaded (maximum load), the back EMF and motor current are almost in phase. Therefore, most related technologies detect motor stalling by detecting the phase shift between the back EMF and motor current. However, detecting back EMF requires external analog circuitry, which is space-consuming, costly, and has high detection requirements.

[0003] Therefore, how to quickly and conveniently detect motor stall while reducing costs and computational complexity is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a motor stall detection system and method to quickly and conveniently detect motor stall, reducing costs and computational complexity.

[0005] To solve the above-mentioned technical problems, the present invention provides a motor stall detection system, characterized in that it includes: A preset register group is used to store a preset number of consecutive electrical half-cycles; wherein the preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; The computing circuit connected to the preset register group is used to calculate the electrical cycle detection value based on all electrical half cycles in the preset register group; The stall fault judgment circuit connected to the calculation circuit is used to determine that the operating condition of the motor under test is a motor stall state when the electrical cycle detection value is greater than or equal to the stall threshold.

[0006] In another aspect, the computing circuit includes: The average value calculation unit connected to the preset register group is used to calculate the average value of all electrical half cycles in the preset register group and store the average value as an electrical cycle detection value in the electrical cycle detection register.

[0007] On the other hand, the preset register group is specifically a shift register group used to store the latest preset number of electrical half cycles.

[0008] On the other hand, the shift register group includes four register groups for storing the latest four consecutive electrical half-cycles.

[0009] On the other hand, the system also includes: The stall threshold re-detection circuit connected to the preset register group is used to calculate the stall threshold based on the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation.

[0010] On the other hand, the system also includes: The re-detection judgment circuit, connected to the preset register group and the stall threshold re-detection circuit, is used to trigger the stall threshold re-detection circuit to start the stall threshold detection and calibration process when the change in the electrical half-cycle is detected to reach the threshold re-detection condition.

[0011] On the other hand, the re-detection determination circuit includes: The first counter is used to increment the count value of the first counter by 1 when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the change threshold; and to decrement the count value of the first counter by 1 when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not greater than the change threshold; wherein the current electrical half-cycle is the latest electrical half-cycle, and the previous electrical half-cycle is the electrical half-cycle preceding the current electrical half-cycle. A first comparison unit connected to the first counter and the stall threshold re-detection circuit is used to determine that the change in the electrical half-cycle has reached the threshold re-detection condition when the count value of the first counter reaches the first count threshold, trigger the stall threshold re-detection circuit to start the stall threshold detection and calibration process, and clear the count value of the first counter to zero.

[0012] On the other hand, the stall threshold re-detection circuit includes: The second counter is used to increment the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the first stable threshold when the motor is running normally; and to decrement the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the first stable threshold. The second comparison unit connected to the second counter is used to output a speed stabilization recording signal to the speed stabilization result register group when the count value of the second counter reaches the second count threshold. The speed stabilization result register group connected to the second comparison unit and the calculation circuit is used to store the current electrical cycle detection value output by the calculation circuit as the electrical cycle detection value of the motor under test when it is running at a steady speed, based on the speed stabilization recording signal. A third comparison unit connected to the second counter and the calculation circuit is used to output a stall count signal to the second counter if the current electrical cycle detection value output by the calculation circuit is less than the stall confirmation threshold after the motor under test stalls; wherein, the second counter is also used to count once every half electrical cycle according to the stall count signal; the second comparison unit is also used to output a stall record signal to the stall result register group when the count value of the second counter reaches the third count threshold; The stall result register group connected to the second comparison unit and the calculation circuit is used to store the current electrical cycle detection value output by the calculation circuit as the electrical cycle detection value of the motor under test when it is running at a steady speed, based on the stall recording signal. The stall threshold calculation unit, connected to the steady speed result register group and the stall result register group, is used to calculate the average value of the electrical cycle detection value of the motor under test during steady speed operation and the electrical cycle detection value during stall operation, so as to obtain the stall threshold. The second counter is further configured to increment the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the second stable threshold after the motor under test resumes normal operation; and decrement the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the second stable threshold. The second comparison unit is further configured to determine that the detection and calibration process of the stall threshold is completed when the count value of the second counter reaches the fourth count threshold.

[0013] On the other hand, the system also includes: An electrical half-cycle difference comparison circuit connected to the first counter, the second counter, and the preset register group is used to calculate the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle; output the comparison result of the absolute value and the change threshold to the first counter; and output the comparison result of the absolute value and the first stable threshold or the second stable threshold to the second counter.

[0014] Furthermore, the present invention also provides a method for detecting motor stall, comprising: Obtain the electrical half-cycle of the motor under test; The electrical cycle detection value is determined based on a preset number of consecutive electrical half-cycles; wherein the preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; and the preset number is a positive integer greater than or equal to 2. When the electrical cycle detection value is greater than or equal to the stall threshold, the operating condition of the motor under test is determined to be a motor stall state.

[0015] The present invention provides a motor stall detection system, comprising: a preset register group for storing a preset number of consecutive electrical half-cycles; wherein the preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; a calculation circuit connected to the preset register group for calculating an electrical cycle detection value based on all electrical half-cycles in the preset register group; and a stall fault judgment circuit connected to the calculation circuit for determining that the operating condition of the motor under test is a motor stall state when the electrical cycle detection value is greater than or equal to a stall threshold.

[0016] As can be seen, this invention utilizes a stall fault judgment circuit to determine the operating condition of the motor under test as a stall state when the electrical cycle detection value is greater than or equal to the stall threshold. It can use electrical cycle detection to compare the back electromotive force between the rising and falling current quadrants, thereby quickly and conveniently detecting the motor stall state, reducing detection costs and computational complexity. By using a preset number of consecutive electrical half-cycles stored in a preset register group to determine the electrical cycle detection value, it can prevent false detections caused by electrical half-cycle jitter, improving the accuracy of motor stall detection. Furthermore, this invention can use digital circuits to implement motor stall detection, occupying a small area and having low cost. In addition, this invention also provides a motor stall detection method, which also has the above-mentioned beneficial effects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a structural block diagram of a motor stall detection system provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of another motor stall detection system provided in an embodiment of the present invention; Figure 3 This is a circuit diagram of another motor stall detection system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the detection process of another motor stall detection system provided in an embodiment of the present invention; Figure 5 This is a flowchart of a motor stall detection method provided in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please refer to Figure 1 , Figure 1 This is a structural block diagram of a motor stall detection system provided in an embodiment of the present invention. The system may include: Preset register group 10 is used to store a preset number of consecutive electrical half-cycles; wherein the preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; The calculation circuit 20, which is connected to the preset register group 10, is used to calculate the electrical cycle detection value based on all electrical half cycles in the preset register group 10. The stall fault judgment circuit 30, which is connected to the calculation circuit 20, is used to determine the operating condition of the motor under test as a stall state when the electrical cycle detection value is greater than or equal to the stall threshold.

[0021] Understandably, the solution of detecting motor stall by detecting electromotive force requires the use of external analog circuits to detect back EMF, which is relatively space-consuming, costly, and has high detection requirements. While controlling the PWM (Pulse Width Modulation) turn-off time by detecting the PWM turn-off time can compare the back EMF between the rising and falling current quadrants, the detection of the PWM turn-off time is relatively complex and frequent. Therefore, this embodiment can compare the back EMF between the rising and falling current quadrants by detecting the electrical cycle, which greatly simplifies the logic operation process in the hardware circuit.

[0022] Correspondingly, the electrical half-cycle stored in the preset register group 10 in this embodiment can be the time for the motor under test to rotate 90°, that is, the full step of the motor under test can include 4 electrical half-cycles, and the full step is one rotation (360°) of the motor. Accordingly, the system provided in this embodiment may also include a data acquisition circuit connected to the preset register group 10, used to acquire the electrical half-cycle of the motor under test and store it in the preset register group 10; the data acquisition circuit can be implemented in the same or similar way as the detection and acquisition circuit of the electrical half-cycle of the motor in related technologies, and this embodiment does not impose any restrictions on it.

[0023] In this embodiment, the electrical cycle detection value can be a value used for motor stall detection. In this embodiment, the calculation circuit 20 can calculate the electrical cycle detection value based on all electrical half cycles (i.e., a preset number of consecutive electrical half cycles) in the preset register group 10. Compared with the scheme of directly using electrical half cycles for motor stall detection, it can avoid false detection caused by electrical half cycle jitter and improve the accuracy of motor stall detection; the preset number can be a positive integer greater than or equal to 2.

[0024] Correspondingly, regarding the specific circuit structure of the calculation circuit 20 in this embodiment, that is, the specific method by which the calculation circuit 20 calculates the electrical cycle detection value based on all electrical half-cycles in the preset register group 10, can be set by the designer according to the practical scenario and user needs. The calculation circuit 20 can calculate the sum of a preset number of consecutive electrical half-cycles and the quotient of a preset number to obtain the electrical cycle detection value; that is, the stall threshold can be the threshold corresponding to the electrical half-cycle. Figure 3 As shown, the calculation circuit 20 may include: an average value calculation unit connected to the preset register group 10 (electrical half-cycle register group 1-4), used to calculate the average value of all electrical half-cycles in the preset register group 10, and store the average value as an electrical cycle detection value in the electrical cycle detection register; that is, as Figure 2 and Figure 3 As shown, the electrical half-cycle average value calculation circuit may include a calculation circuit 20 and a preset register group 10. The calculation circuit 20 may also directly calculate the sum of a preset number of consecutive electrical half-cycles to obtain the electrical cycle detection value, i.e., the stall threshold may be the threshold corresponding to the preset number of electrical half-cycles. This embodiment does not impose any limitations on this.

[0025] Similarly, the specific structure of the preset register group 10 in this embodiment, i.e., the specific value of the preset quantity, can be set by the designer. For example, the preset quantity can be an integer multiple of 2 or 4, or other values ​​greater than 2. For example, the preset quantity can be 4, that is, the preset register group 10 can include 4 register groups to store 4 consecutive electrical half-cycles, so as to determine the electrical cycle detection value using the 4 electrical half-cycles corresponding to the full step of the motor, and ensure the detection accuracy.

[0026] Furthermore, to facilitate the storage and use of the latest preset number of consecutive electrical half-cycles, in this embodiment, the preset register group 10 can be a shift register group, so as to realize the storage of the latest preset number of electrical half-cycles by shifting. For example, such as Figure 3 and Figure 4As shown, when the preset quantity is 4, the shift register group can include 4 register groups to store the latest 4 consecutive electrical half-cycles; that is, the latest 4 consecutive electrical half-cycles will be shifted and stored into these 4 register groups in sequence. The 4 register groups are electrical half-cycle register group 1 (T1), electrical half-cycle register group 2 (T2), electrical half-cycle register group 3 (T3), and electrical half-cycle register group 4 (T4). The latest electrical half-cycle is Tn (it will be updated every electrical half-cycle. For example, the first electrical half-cycle will be stored in T1, the value in T4 will be discarded in the second electrical half-cycle, the value in T3 will be stored in T4, the value in T2 will be stored in T3, the value in T1 will be stored in T2, and then the second electrical half-cycle will be stored in T1, and so on for subsequent electrical half-cycles). The current electrical cycle detection value (T) output by the calculation circuit 20 is calculated. COIL ) can be the average of the electrical half-cycles in the four register groups, i.e., T COIL =(T1+T2+T3+T4) / 4; that is, the average value calculation unit can calculate the average value of the four electrical half cycles in the shift register group as the current electrical cycle detection value (current electrical cycle detection value).

[0027] It is understood that the stall threshold in this embodiment can be a pre-set threshold for detecting motor stall. The stall fault judgment circuit 30 in this embodiment can compare the current electrical cycle detection value with the stall threshold to determine the current operating status of the motor under test; for example... Figure 3 As shown, the stall fault detection circuit 30 may include: a stall fault comparison unit, used to detect the value (T) during an electrical cycle. COIL ) is greater than or equal to the stall threshold (T) TH When the operating condition of the motor under test is determined to be a motor stall state, a corresponding operating condition signal (COM_fault) is output, which is the signal of the motor stall state (e.g., 1); that is, COM_fault can represent T COIL With T TH The comparison results.

[0028] Correspondingly, such as Figure 3 As shown, the stall fault judgment circuit 30 may further include a fault circuit unit connected to the stall fault comparison unit, used to latch and report a fault based on the received motor stall state signal (e.g., setting the fault flag FAULT to 1); that is, when the operating condition of the motor under test is a motor stall state, the fault is latched and reported. Correspondingly, the fault circuit unit may also control the motor under test according to a preset stall control logic when the operating condition of the motor under test is a motor stall state, for example, immediately stopping the motor under test.

[0029] In this embodiment, the specific value of the stall threshold can be set by the designer according to the practical scenario and user needs. For example, the stall threshold can be a pre-set fixed value. To improve the accuracy of motor stall detection, the stall threshold can also be an automatically detected value; for example, the stall threshold can be calculated based on the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation. That is to say, the system provided in this embodiment can also include a stall threshold re-detection circuit connected to the preset register group 10, used to calculate the stall threshold based on the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation. For example, the stall threshold can be the electrical cycle detection value (T) of the motor under test during steady-speed operation. STAB ) and the electrical cycle detection value during stall operation (T) STALL The average value of ), i.e., the stall threshold T TH =(T STAB +T STALL ) / 2; In other words, the stall threshold detection circuit can calculate the average of the electrical cycle detection value of the motor under test when it is running at steady speed and the electrical cycle detection value when it is running at stall speed, and obtain the stall threshold.

[0030] Furthermore, to improve the accuracy of motor stall detection, this embodiment can also include a re-detection judgment circuit. This circuit can trigger the stall threshold re-detection circuit to initiate the stall threshold detection and calibration process by monitoring changes in the electrical half-cycle. For example, the re-detection judgment circuit can be connected to the preset register group 10 and the stall threshold re-detection circuit to trigger the stall threshold re-detection circuit to initiate the stall threshold detection and calibration process when a change in the electrical half-cycle is detected to meet the threshold re-detection condition.

[0031] The specific circuit structure of the aforementioned re-detection judgment circuit, i.e., the specific method for detecting whether the change in the electrical half-cycle reaches the threshold re-detection condition, can be set by the designer according to the practical scenario and user needs. For example, the current electrical half-cycle (e.g., Figure 4 T1 in the middle) and the previous electrical half-cycle (such as T1 in the middle) and the previous electrical half-cycle (such Figure 4 The absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle (or the absolute value of the difference between the previous electrical half-cycle and the current electrical half-cycle) is taken as the change in electrical half-cycle. The absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle can be calculated. Here, the current electrical half-cycle is the latest electrical half-cycle stored in the preset register group 10, and the previous electrical half-cycle is the electrical half-cycle before the current electrical half-cycle, that is, the latest electrical half-cycle before the current electrical half-cycle. For example, the re-detection judgment circuit may include: a first counter, used to set the count value of the first counter (such as T2) when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the change threshold. Figure 3 and Figure 4 The first comparison unit, connected to the first counter and the stall threshold re-detection circuit, increments the CNTA value by 1; it is used to increment the CNTA value by 1 when the count value of the first counter reaches the first counting threshold (e.g., the first counter). Figure 3 When CNT_th1 is reached, the change in the electrical half-cycle is determined to meet the threshold re-detection condition, triggering the stall threshold re-detection circuit to start the stall threshold detection and calibration process, and resetting the count value of the first counter to zero; if Figure 3 As shown, the first comparison unit can be used when CNTA ≥ the first counting threshold (e.g., Figure 4 When the change in the electrical half-cycle reaches the threshold re-detection condition (64), a corresponding detection calibration signal (such as STAL_EN=1) is sent to the stall threshold re-detection circuit and the first counter to trigger the stall threshold re-detection circuit to start the stall threshold detection calibration process and clear the count value of the first counter to zero.

[0032] Correspondingly, when the absolute value of the first counter is not greater than the change threshold, the count value of the first counter can be decremented by 1; alternatively, when the absolute value is not greater than the change threshold, the count value of the first counter can be left unchanged and the system can wait directly for the triggering of the next electrical half-cycle. This embodiment does not impose any restrictions on this.

[0033] Accordingly, the system provided in this embodiment may further include an electrical half-cycle difference comparison circuit connected to the first counter and the preset register group 10, used to calculate the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle; and output the comparison result of the absolute value and the change threshold to the first counter, so that the first counter can adjust its own count value according to the comparison result. Figure 3 As shown, the electrical half-cycle difference comparison circuit may include a subtractor connected to the preset register group 10, used to calculate the absolute value of the difference between the current electrical half-cycle (T1) and the previous electrical half-cycle (T2); and an electrical half-cycle comparison unit connected to the subtractor and the first counter, used to output the comparison result (COM_A) of the absolute value (Tdout) and the change threshold (CNT_change) to the first counter.

[0034] The specific circuit structure of the stall threshold re-detection circuit, i.e., the specific threshold re-detection method in the stall threshold detection and calibration process, can be set by the designer according to the practical scenario and user requirements. Figure 3 As shown, the stall threshold re-detection circuit may include: a second counter, used to, during normal motor operation, if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than a first stability threshold, then increment the count value of the second counter (e.g., ...). Figure 4 The second comparison unit, connected to the second counter, is used to increment the count value of the second counter by 1 when the count value of the second counter reaches the second count threshold (CNT_th2, e.g., CNT_th). Figure 4 When 64 is reached, a speed stabilization recording signal (e.g., STAB_EN=1) is output to the speed stabilization result register group; the speed stabilization result register group, connected to the second comparison unit and the calculation circuit 20, is used to store the current electrical cycle detection value (T) output by the calculation circuit 20 according to the speed stabilization recording signal. COIL ) is used as the electrical cycle detection value (T) of the motor under test during steady-speed operation. STAB ); where the current electrical cycle detection value can be the electrical cycle detection value currently output by the calculation circuit 20, or it can be calculated separately using the contents of the preset register group 10; The third comparison unit, connected to the second counter and the calculation circuit 20, is used to, after controlling the motor under test to stall, if the current electrical cycle detection value (T) output by the calculation circuit 20 is... COIL ) less than the stall confirmation threshold (e.g., T) STAB If CNT_stall is reached, a stall count signal (e.g., COM_stall=1) is output to the second counter; the second counter is also used to count once every half electrical cycle according to the stall count signal, that is, to perform periodic counting with the electrical half cycle as the counting period; the second comparison unit is also used to count once when the count value of the second counter reaches the third counting threshold (CNT_th3, e.g., ...). Figure 4 When 32) is reached, a stall recording signal is output to the stall result register group (e.g., STALL_EN=1). The stall result register group, connected to the second comparison unit and the calculation circuit 20, is used to store the current electrical cycle detection value (T) output by the calculation circuit 20 based on the stall recording signal. COIL ) is used as the electrical cycle detection value (T) of the motor under test during steady-speed operation. STALL ); The stall threshold calculation unit, connected to the steady-speed result register group and the stall result register group, is used to calculate the average of the electrical cycle detection values ​​of the motor under test during steady-speed operation and the electrical cycle detection values ​​during stall operation, to obtain the stall threshold (T). TH ).

[0035] Furthermore, the second counter can also be used to increment the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the second stable threshold after the motor under test resumes normal operation; the second comparison unit is also used to increment the count value of the second counter by 1 when the count value of the second counter reaches the fourth counting threshold (CNT_th4, e.g., Figure 4When step 64) is completed, the stall threshold detection and calibration process is deemed complete. For example, setting the calibration end signal (STAL_OVER) to 1 indicates the stall threshold detection and calibration process is finished, avoiding any impact on subsequent stall detection. That is, the stall fault judgment circuit 30 can perform the detection of the motor's operating status only after the stall threshold detection and calibration process is completed (e.g., STAL_OVER=1). During the stall threshold re-detection, the stall protection may not function. Figure 3 As shown, the second counter can restart counting when STALL_EN=1 (i.e., when a stall recording signal is received). Figure 4 China T STALL = T COIL (The process of CNTB=0) is such that when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the second stable threshold after the motor under test resumes normal operation, the count value of the second counter is incremented by 1.

[0036] Correspondingly, the second counter can decrement its count by 1 when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the first stable threshold; alternatively, it can remain unchanged and wait for the triggering of the next electrical half-cycle. Similarly, the second counter can decrement its count by 1 when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the second stable threshold; alternatively, it can remain unchanged and wait for the triggering of the next electrical half-cycle.

[0037] Correspondingly, during the stall threshold detection and calibration process, the stall threshold re-detection circuit can control the stall protection to not function, such as controlling the stall fault judgment circuit 30 and / or the motor control circuit to not start, so as to avoid the false triggering of the stall protection.

[0038] Furthermore, during the stall threshold re-detection circuit triggering the stall threshold detection and calibration process, the re-detection judgment circuit can also re-trigger the stall threshold re-detection circuit when it detects that the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is greater than the re-detection threshold (such as the aforementioned change threshold), so as to re-perform the stall threshold detection and calibration process and improve the accuracy of the stall threshold.

[0039] The specific values ​​for the various thresholds mentioned above, such as the values ​​stored in the corresponding threshold registers, can be set by the designer according to the practical scenario and user needs. For example, the first stable threshold can be equal to the second stable threshold, and both can be 5% of the previous electrical half-cycle (e.g., ...). Figure 4 T2 in 5%), or 5% of the current electrical half-cycle, or other values. The change threshold can be 10% of the previous electrical half-cycle (e.g., 5%). Figure 4T2 in 10%), or 10% of the current electrical half-cycle, or other values; the stall confirmation threshold can be the electrical cycle detection value (T) of the motor under test when it is running at steady speed. STAB ) and preset percentage (CNT_stall, such as Figure 4 The product of 62.5% (of which), such as Figure 4 T in STAB 62.5%. The first to fourth counting thresholds can be 64, 64, 32, and 64 respectively, or other values ​​can be used. This embodiment does not impose any restrictions on this.

[0040] For example, such as Figure 4 As shown, the latest four consecutive electrical half-cycles are sequentially shifted and stored in four register groups of preset register group 10, namely T1, T2, T3, and T4, with the latest electrical half-cycle being Tn. The averaging circuit calculates the average value of the four electrical half-cycles in the shifted register group as the current electrical cycle detection value and stores it in the electrical cycle detection register. The electrical half-cycle difference comparison circuit calculates the absolute value of the difference between the previous electrical half-cycle and the current electrical half-cycle (i.e., the absolute value of the difference); when the absolute value of the difference is greater than 10% of the previous electrical half-cycle (indicating a change in motion state), the count value (CNTA) of the first counter is incremented by 1; otherwise, the first counter is decremented by 1. When the value in the first counter is greater than or equal to 64, the re-detection judgment circuit sets the stall threshold detection calibration signal (STAL_EN) to 1 to trigger the stall threshold re-detection circuit to start the stall threshold detection calibration process, that is, to enable the stall threshold re-detection function, and clears the value of the first counter to zero.

[0041] During stall threshold re-detection, the stall threshold re-detection circuit uses the electrical half-cycle difference comparison circuit to calculate the absolute value of the difference between the current and previous electrical half-cycles. If the absolute value of the difference is less than 5% of the previous electrical half-cycle (indicating speed stability), the count value (CNTB) of the second counter is incremented by 1; otherwise, the second counter is decremented by 1. The second comparison unit can store the value of the electrical cycle detection register into the speed stabilization result register T when the value in the second counter is greater than or equal to 64. STAB In the middle, the second counter is reset to zero. This causes the motor to stall, because when the motor stalls, the half-cycle value suddenly decreases, and in the current T... COIL <T STAB At 62.5%, the second counter counts once per electrical half-cycle. When the value in the second counter equals 32, T is reset. COIL The value is stored in the stall result register T STALLIn the middle, the second counter is cleared to zero. The stall threshold calculation unit calculates the stall threshold T. TH =(T STAB +T STALL ) / 2. To restore normal motor operation, the absolute value of the difference between the current and previous electrical half-cycles is calculated using the electrical half-cycle difference comparison circuit. If the absolute value of the difference is less than 5% of the previous electrical half-cycle, the second counter is incremented by 1; otherwise, the second counter is decremented by 1. When the value in the second counter equals 64, the stall threshold re-detection is confirmed to be complete (e.g., setting STAL_OVER=1), and the second counter is reset to zero. During the stall threshold re-detection, stall protection is inactive.

[0042] After the stall threshold is re-detected, during subsequent operation, the stall fault detection circuit 30 will detect a T fault. COIL >=T TH When a motor stall is detected, the fault will be latched and reported (FAULT=1). The motor control circuit can also be used to immediately stop the motor after a fault occurs. The electrical half-cycle difference comparison circuit can increment the count value of the first counter by 1 when the absolute value of the difference between the previous electrical half-cycle and the current electrical half-cycle is greater than 10% of the previous electrical half-cycle, so as to recalibrate the stall threshold detection in subsequent cycles.

[0043] In this embodiment, the stall fault judgment circuit 30 determines the motor's operating condition as a stall state when the electrical cycle detection value is greater than or equal to the stall threshold. It can use electrical cycle detection to compare the back EMF between the rising and falling current quadrants, thereby quickly and conveniently detecting the motor stall state, reducing detection costs and computational complexity. By using a preset number of consecutive electrical half-cycles stored in the preset register group 10 to determine the electrical cycle detection value, it can prevent false detections caused by electrical half-cycle jitter and improve the accuracy of motor stall detection. Furthermore, this invention can use digital circuits to detect motor stall, occupying a small area and having low cost.

[0044] Corresponding to the above system embodiments, this invention also provides a motor stall detection method. The motor stall detection method described below and the motor stall detection system described above can be referred to each other.

[0045] Please refer to Figure 5 , Figure 5 This is a flowchart illustrating a motor stall detection method provided in an embodiment of the present invention. The method may include: Step 101: Obtain the electrical half-cycle of the motor to be tested.

[0046] It is understood that the electrical half-cycle in this embodiment can be the time it takes for the motor under test to rotate 90°, that is, the full step of the motor under test can include 4 electrical half-cycles, and the full step is one rotation (360°) of the motor. The specific method for obtaining the electrical half-cycle of the motor under test in this step can be set by the designer, such as using the same or similar method as the electrical half-cycle detection method of motor in related technologies. This embodiment does not impose any restrictions on this.

[0047] Step 102: Determine the electrical cycle detection value based on a preset number of consecutive electrical half cycles.

[0048] The preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; the preset number is a positive integer greater than or equal to 2.

[0049] In some embodiments, after step 101, the electrical half-cycle can be stored in a shift register group; wherein, the shift register group is used to store the latest preset number of electrical half-cycles; correspondingly, in this step, all electrical half-cycles in the shift register group can be used to determine the electrical cycle detection value.

[0050] In some embodiments, this step may calculate the sum of a preset number of consecutive electrical half-cycles and the quotient of a preset number to obtain the electrical cycle detection value.

[0051] Step 103: When the electrical cycle detection value is greater than or equal to the stall threshold, the operating condition of the motor under test is determined to be a motor stall state.

[0052] It is understood that the stall threshold in this embodiment can be a pre-set threshold for detecting motor stall. The specific value of the stall threshold in this embodiment can be set by the designer, such as a pre-set fixed value. To improve the accuracy of motor stall detection, the stall threshold can also be an automatically detected value; for example, the stall threshold can be calculated based on the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation. For instance, the stall threshold can be the electrical cycle detection value (T) of the motor under test during steady-speed operation. STAB ) and the electrical cycle detection value during stall operation (T) STALL The average value of ), i.e., the stall threshold T TH =(T STAB +T STALL ) / 2. In other words, the method provided in this embodiment may also include a stall threshold detection and calibration process, such as calculating the stall threshold based on the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation.

[0053] Furthermore, to improve the accuracy of motor stall detection, this embodiment can also trigger a stall threshold detection and calibration process by monitoring changes in the electrical half-cycle. This allows for adjustment and updating of the stall threshold when significant changes in the electrical half-cycle occur, ensuring the accuracy of motor stall detection. For example, after step 101, the method provided in this embodiment can trigger the stall threshold detection and calibration process when a change in the electrical half-cycle reaches the threshold re-detection condition.

[0054] Correspondingly, the specific settings for the aforementioned threshold re-detection conditions, i.e., the specific method for detecting whether the change in the electrical half-cycle reaches the threshold re-detection condition, can be set by the designer according to the practical scenario and user needs. For example, the current electrical half-cycle (e.g., Figure 2 T1 in the middle) and the previous electrical half-cycle (such as T1 in the middle) and the previous electrical half-cycle (such Figure 2 The absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle (or the absolute value of the difference between the previous electrical half-cycle and the current electrical half-cycle) is taken as the change in electrical half-cycle. The absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle can be calculated. Here, the current electrical half-cycle is the latest electrical half-cycle, and the previous electrical half-cycle is the electrical half-cycle before the current electrical half-cycle, that is, the latest electrical half-cycle before the current electrical half-cycle. If the absolute value is greater than the change threshold, the count value of the first counter ( Figure 2 The count value of the first counter is incremented by 1; if the count value of the first counter reaches the first counting threshold, it is determined that the change of the electrical half-cycle has reached the threshold re-detection condition, triggering the stall threshold detection and calibration process, and the count value of the first counter is cleared to zero.

[0055] Correspondingly, for cases where the absolute value is not greater than the change threshold, the designer can set it themselves. For example, when the absolute value is not greater than the change threshold, the count value of the first counter can be decremented by 1; or when the absolute value is not greater than the change threshold, the count value of the first counter can be left unchanged, and the process can end or wait for the next electrical half-cycle.

[0056] The detection and calibration process for the aforementioned stall threshold can be customized by the designer based on practical scenarios and user needs. For example, the electrical cycle detection values ​​of the motor under test during steady-speed operation and during stall operation can be obtained. The stall threshold can then be calculated using these two values. For instance, during normal motor operation, if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the first stability threshold, then the count value of the second counter (such as...) will be... Figure 2 Increment the count value of the second counter (CNTB) by 1; where the current electrical half-cycle is the latest electrical half-cycle, and the previous electrical half-cycle is the electrical half-cycle preceding the current electrical half-cycle; if the count value of the second counter reaches the second counting threshold (e.g. Figure 2(64) Then, based on a preset number of consecutive first electrical half-cycles, determine the electrical cycle detection value of the motor under test during steady-speed operation, and clear the count value of the second counter to zero; wherein, the preset number of consecutive first electrical half-cycles is the current electrical half-cycle and the historical number of electrical half-cycles before the current electrical half-cycle; the historical number is the preset number minus 1; control the motor under test to stall, and calculate the current electrical cycle detection value based on a preset number of consecutive second electrical half-cycles; wherein, the preset number of consecutive second electrical half-cycles is the current electrical half-cycle and the historical number of electrical half-cycles before the current electrical half-cycle; if the current electrical cycle detection value is less than the stall confirmation threshold, control the second counter to count cyclically according to electrical half-cycles, and when the count value of the second counter reaches the third counting threshold (e.g. Figure 2 When (32) is reached, the current electrical cycle detection value is determined as the electrical cycle detection value of the motor under test during stall operation, and the count value of the second counter is cleared to zero; the average value of the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation is calculated to obtain the stall threshold; the motor under test is controlled to resume normal operation. If the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the second stable threshold, the count value of the second counter is incremented by 1; if the count value of the second counter reaches the fourth counting threshold (e.g., ... Figure 2 If 64 is selected, then the detection and calibration process for determining the stall threshold is complete.

[0057] Correspondingly, for the case where the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the first stability threshold, the designer can set this value, such as decrementing the count value of the second counter by 1; alternatively, the count value of the second counter can remain unchanged, ending the current process or waiting for the next electrical half-cycle. Similarly, for the case where the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the second stability threshold, the designer can set this value, such as decrementing the count value of the second counter by 1; alternatively, the count value of the second counter can remain unchanged, ending the current process or waiting for the next electrical half-cycle.

[0058] Correspondingly, during the stall threshold detection and calibration process, the stall protection can be controlled to not function, such as not performing step 103 or the motor stall processing process, in order to avoid the erroneous triggering of the stall protection.

[0059] Furthermore, during the stall threshold detection and calibration process, if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is greater than the re-detection threshold (such as the aforementioned change threshold), the stall threshold detection and calibration process can be re-triggered to improve the accuracy of the stall threshold.

[0060] It should be noted that the method provided in this embodiment can be implemented by a processor executing a corresponding computer program, or by a hardware logic circuit (such as a digital circuit) structure (such as the structure provided in the previous system embodiment). This embodiment does not impose any restrictions on this.

[0061] In this embodiment, the present invention determines the operating condition of the motor under test as a stall state when the electrical cycle detection value is greater than or equal to the stall threshold. It can use electrical cycle detection to compare the back EMF between the rising and falling current quadrants, thereby quickly and conveniently detecting the stall state of the motor, reducing detection costs and computational complexity. Furthermore, by determining the electrical cycle detection value based on a preset number of consecutive electrical half-cycles, it can prevent false detections caused by electrical half-cycle jitter and improve the accuracy of detecting motor stall.

[0062] Corresponding to the system and method embodiments above, this invention also provides a motor stall detection device. The motor stall detection device described below can be referred to in conjunction with the motor stall detection system and motor stall detection method described above.

[0063] Please refer to Figure 4 , Figure 4 This is a schematic diagram of a motor stall detection device provided in an embodiment of the present invention. The device may include: The motor stall detection system provided in the above system embodiments; Alternatively, a memory and a processor; wherein the memory is used to store a computer program; and the processor is used to implement the steps of the motor stall detection method provided in the above method embodiments when executing the computer program.

[0064] Corresponding to the above method embodiments, this invention also provides a computer program product. The computer program product described below can be referred to in correspondence with the motor stall detection method described above.

[0065] A computer program product includes a computer program / instructions that, when executed by a processor, implement the steps of the motor stall detection method provided in the above-described method embodiments.

[0066] Corresponding to the above method embodiments, this invention also provides a computer-readable storage medium, the computer-readable storage medium described below corresponding to the motor stall detection method described above.

[0067] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the motor stall detection method described in the above method embodiments.

[0068] The computer-readable storage medium can specifically be a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, or any other readable storage medium capable of storing program code.

[0069] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The methods, devices, computer program products, and computer-readable storage media disclosed in the embodiments are described simply because they correspond to the systems disclosed in the embodiments; relevant details can be found in the method section.

[0070] The present invention provides a detailed description of a motor stall detection system and method. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely illustrative and are intended to help understand the method and core concepts of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A motor stall detection system, characterized in that, include: A preset register group is used to store a preset number of consecutive electrical half-cycles; wherein the preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; The computing circuit connected to the preset register group is used to calculate the electrical cycle detection value based on all electrical half cycles in the preset register group; The stall fault judgment circuit connected to the calculation circuit is used to determine that the operating condition of the motor under test is a motor stall state when the electrical cycle detection value is greater than or equal to the stall threshold.

2. The motor stall detection system according to claim 1, characterized in that, The computing circuit includes: The average value calculation unit connected to the preset register group is used to calculate the average value of all electrical half cycles in the preset register group and store the average value as an electrical cycle detection value in the electrical cycle detection register.

3. The motor stall detection system according to claim 1, characterized in that, The preset register group is specifically a shift register group, used to store the latest preset number of electrical half cycles.

4. The motor stall detection system according to claim 3, characterized in that, The shift register group comprises four register groups for storing the latest four consecutive electrical half-cycles.

5. The motor stall detection system according to any one of claims 1 to 4, characterized in that, Also includes: The stall threshold re-detection circuit connected to the preset register group is used to calculate the stall threshold based on the electrical cycle detection value of the motor under test during steady-speed operation and the electrical cycle detection value during stall operation.

6. The motor stall detection system according to claim 5, characterized in that, Also includes: The re-detection judgment circuit, connected to the preset register group and the stall threshold re-detection circuit, is used to trigger the stall threshold re-detection circuit to start the stall threshold detection and calibration process when the change in the electrical half-cycle is detected to reach the threshold re-detection condition.

7. The motor stall detection system according to claim 6, characterized in that, The re-detection judgment circuit includes: The first counter is used to increment the count value of the first counter by 1 when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the change threshold; and to decrement the count value of the first counter by 1 when the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not greater than the change threshold; wherein the current electrical half-cycle is the latest electrical half-cycle, and the previous electrical half-cycle is the electrical half-cycle preceding the current electrical half-cycle. A first comparison unit connected to the first counter and the stall threshold re-detection circuit is used to determine that the change in the electrical half-cycle has reached the threshold re-detection condition when the count value of the first counter reaches the first count threshold, trigger the stall threshold re-detection circuit to start the stall threshold detection and calibration process, and clear the count value of the first counter to zero.

8. The motor stall detection system according to claim 7, characterized in that, The stall threshold re-detection circuit includes: The second counter is used to increment the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the first stable threshold when the motor is running normally; and to decrement the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the first stable threshold. The second comparison unit connected to the second counter is used to output a speed stabilization recording signal to the speed stabilization result register group when the count value of the second counter reaches the second count threshold. The speed stabilization result register group connected to the second comparison unit and the calculation circuit is used to store the current electrical cycle detection value output by the calculation circuit as the electrical cycle detection value of the motor under test when it is running at a steady speed, based on the speed stabilization recording signal. A third comparison unit connected to the second counter and the calculation circuit is used to output a stall count signal to the second counter if the current electrical cycle detection value output by the calculation circuit is less than the stall confirmation threshold after the motor under test stalls; wherein, the second counter is also used to count once every half electrical cycle according to the stall count signal; the second comparison unit is also used to output a stall record signal to the stall result register group when the count value of the second counter reaches the third count threshold; The stall result register group connected to the second comparison unit and the calculation circuit is used to store the current electrical cycle detection value output by the calculation circuit as the electrical cycle detection value of the motor under test when it is running at a steady speed, based on the stall recording signal. The stall threshold calculation unit, connected to the steady speed result register group and the stall result register group, is used to calculate the average value of the electrical cycle detection value of the motor under test during steady speed operation and the electrical cycle detection value during stall operation, so as to obtain the stall threshold. The second counter is further configured to increment the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is less than the second stable threshold after the motor under test resumes normal operation; and decrement the count value of the second counter by 1 if the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle is not less than the second stable threshold. The second comparison unit is further configured to determine that the detection and calibration process of the stall threshold is completed when the count value of the second counter reaches the fourth count threshold.

9. The motor stall detection system according to claim 8, characterized in that, Also includes: An electrical half-cycle difference comparison circuit connected to the first counter, the second counter, and the preset register group is used to calculate the absolute value of the difference between the current electrical half-cycle and the previous electrical half-cycle; and output the comparison result of the absolute value and the change threshold to the first counter; The comparison result between the absolute value and the first stable threshold or the second stable threshold is output to the second counter.

10. A method for detecting motor stall, characterized in that, include: Obtain the electrical half-cycle of the motor under test; The electrical cycle detection value is determined based on a preset number of consecutive electrical half-cycles; wherein the preset number of consecutive electrical half-cycles includes the latest electrical half-cycle; and the preset number is a positive integer greater than or equal to 2. When the electrical cycle detection value is greater than or equal to the stall threshold, the operating condition of the motor under test is determined to be a motor stall state.

Images