Motor startup control method, device, motor and storage medium

Abstract

The present invention discloses a motor startup control method, device, motor, and storage medium. The method includes: when the motor needs to be started, controlling the motor's enable signal to be equal to 1; when the motor's enable signal is equal to 1, obtaining the motor's rotational speed, recording it as the motor's current rotational speed; obtaining the motor's rotor position parameter at the current moment, recording it as the current rotor position parameter; and controlling the motor's startup based on the motor's current rotational speed and the motor's current rotor position parameter. This solution ensures the motor's normal operation when started with a tailwind by identifying the length of the rotor position signal based on setting a motor startup speed threshold.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and specifically relates to a motor startup control method, device, motor and storage medium, and more particularly to a high-speed motor startup control method, device, motor and storage medium. Background Art

[0002] In fan-type motor applications, there is a possibility that the load may be affected by external wind or the load may not stop rotating. If the power is turned on again, the initial speed of the motor may not be zero when it starts. This is called a tailwind start. However, tailwind start triggers overcurrent protection, causing the motor to shut down.

[0003] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a motor starting control method, device, motor and storage medium to solve the problem that the overcurrent protection will be triggered after the motor is started with a tailwind, thereby causing the motor to shut down, so as to achieve the effect of ensuring that the motor can operate normally when started with a tailwind by identifying the length of the rotor position signal on the basis of setting the motor starting speed threshold.

[0005] The present invention provides a motor startup control method, comprising: when the motor needs to be started, controlling an enable signal of the motor to be equal to 1; when the enable signal of the motor is equal to 1, obtaining the rotational speed of the motor, which is recorded as the current rotational speed of the motor; obtaining a rotor position parameter of the motor at a current moment, which is recorded as the current rotor position parameter; and controlling the startup of the motor according to the current rotational speed of the motor and the current rotor position parameter of the motor.

[0006] In some embodiments, the motor is controlled to start according to the current speed of the motor and the current rotor position parameters of the motor, including: determining whether the current speed of the motor is less than a set speed threshold; if the current speed of the motor is greater than or equal to the speed threshold, returning after a first set delay to continue determining whether the current speed of the motor is less than the set speed threshold; if the current speed of the motor is less than the speed threshold, controlling the motor to start according to the current rotor position parameters of the motor.

[0007] In some embodiments, the motor is controlled to start according to the current rotor position parameter of the motor, including: determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment; wherein the rotor position parameter of the motor at the previous moment is the rotor position parameter of the motor at the previous moment, recorded as the rotor position parameter at the previous moment; if the current rotor position parameter of the motor is not equal to the rotor position parameter of the motor at the previous moment, then returning after a second set time length to continue to determine whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment; if the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment, then controlling the motor to enter a preset startup subroutine to achieve startup control of the motor.

[0008] In some implementations, the current rotor position parameter of the motor and the rotor position parameter of the motor at a previous moment include: a rotor position signal length.

[0009] Matching the above method, the present invention provides a motor starting control device on the other hand, including: a control unit, configured to control the enable signal of the motor to be equal to 1 when the motor needs to be started; an acquisition unit, configured to obtain the speed of the motor when the enable signal of the motor is equal to 1, recorded as the current speed of the motor; obtain the rotor position parameter of the motor at the current moment, recorded as the current rotor position parameter; the control unit is also configured to control the starting of the motor according to the current speed of the motor and the current rotor position parameter of the motor.

[0010] In some embodiments, the control unit controls the start-up of the motor according to the current speed of the motor and the current rotor position parameters of the motor, including: determining whether the current speed of the motor is less than a set speed threshold; if the current speed of the motor is greater than or equal to the speed threshold, returning after a first set delay to continue determining whether the current speed of the motor is less than the set speed threshold; if the current speed of the motor is less than the speed threshold, controlling the start-up of the motor according to the current rotor position parameters of the motor.

[0011] In some embodiments, the control unit controls the start-up of the motor according to the current rotor position parameter of the motor, including: determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment; wherein the rotor position parameter of the motor at the previous moment is the rotor position parameter of the motor at the previous moment, recorded as the rotor position parameter at the previous moment; if the current rotor position parameter of the motor is not equal to the rotor position parameter of the motor at the previous moment, then returning after a second set time length to continue determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment; if the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment, then controlling the motor to enter a preset start-up subroutine to realize start-up control of the motor.

[0012] In some implementations, the current rotor position parameter of the motor and the rotor position parameter of the motor at a previous moment include: a rotor position signal length.

[0013] Matching the above device, the present invention further provides a motor, including: the above-mentioned motor starting control device.

[0014] In accordance with the above method, the present invention further provides a storage medium, which includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the above-mentioned motor startup control method.

[0015] Therefore, the solution of the present invention, on the basis of setting the motor starting speed threshold, by identifying the length of the rotor position signal, performs real-time detection of the speed and position sensor signal after the motor is powered on. When the speed is less than or equal to a certain speed and the length of the position sensor signal is uniform, the drive signal is output to the corresponding winding according to the rotor position to ensure that the motor can operate normally when started with a tailwind; thus, by identifying the length of the rotor position signal on the basis of setting the motor starting speed threshold, the motor can operate normally when started with a tailwind.

[0016] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a flow chart of an embodiment of a method for controlling the start-up of a motor according to the present invention;

[0019] Figure 21. A flow chart of an embodiment of a method for controlling the start-up of a motor according to motor speed and rotor position parameters in the present invention;

[0020] Figure 3 1 is a flow chart of an embodiment of a method for controlling the start-up of a motor according to rotor position parameters in the present invention;

[0021] Figure 4 Schematic diagram of the structure of an embodiment of a motor starting control device of the present invention;

[0022] Figure 5 This is a schematic diagram of the internal mechanism of the motor running at speed when power is not supplied;

[0023] Figure 6 Schematic diagram of the principle of triggering overcurrent protection during downwind starting of the motor, where (a) is a schematic diagram of the internal mechanism of motor operation, and (b) is a schematic diagram of the principle of triggering overcurrent protection;

[0024] Figure 7 Schematic diagrams of the waveforms of the HALL signal and excitation voltage when the motor is running under different working conditions, where (a) is the waveform diagram when the motor is running at a constant speed, and (b) is the waveform diagram when the speed fluctuates;

[0025] Figure 8 It is a waveform diagram of the HALL signal in the low speed section;

[0026] Figure 9 1 is a flowchart of the improved motor starting method of the present invention.

[0027] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0028] 102 - acquisition unit; 104 - control unit. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Figure 5 This is a schematic diagram of the internal mechanism of the motor running at speed when the power is not on. For permanent magnet fans such as brushless DC motors, when the motor rotates, the stator winding coil cuts the rotor magnetic field generated by the rotation of the permanent magnet, which will generate a back electromotive force proportional to the motor speed. For details, please refer to Figure 5 Example shown.

[0031] Figure 6 The schematic diagram of the principle of triggering overcurrent protection when the motor starts downwind, where (a) is the schematic diagram of the internal mechanism of the motor operation, and (b) is the schematic diagram of the principle of triggering overcurrent protection. When the motor is still rotating after power failure, the stator winding is energized. Due to the starting excitation voltage, the power tube turn-on voltage drop and the winding resistance R s are very small, so the current through the winding will suddenly change during startup, which is likely to trigger the overcurrent protection function of the motor control board. For details, please refer to Figure 6 (a) and Figure 6 In the example shown in (b), the device cannot be restarted in a short period of time, affecting the user experience.

[0032] exist Figure 5 ,as well as Figure 6 In the example shown in (a), the middle rectangle is the motor rotor, the two outer circles represent the windings on both sides of the armature teeth, × represents current inflow, · represents current outflow, and the solid lines with arrows are the magnetic field lines of the rotor; Figure 6 The upper part of (b) is a schematic diagram of a single comparator, where CMPIN+ is the non-inverting input signal, CMPIN- is the inverting input signal, and CMPOUT is the output signal. The lower part is a schematic diagram of the corresponding relationship between the comparator input and output signals.

[0033] To address the above problem, in some solutions, after determining that the motor is started with a tailwind, the motor is started according to the tailwind starting voltage (V1), which is lower than the static starting voltage (V0). Different starting voltages actually correspond to different starting speeds, that is, the tailwind starting speed is lower than the static starting speed; in other solutions, by setting three speed frequency thresholds, such as the first speed frequency threshold f4, the second speed frequency threshold f5, and the third speed frequency threshold f6, four starting conditions are divided, and different starting strategies are proposed for each starting condition.

[0034] It can be seen from these solutions that most of the existing technical solutions for downwind starting in the fan field adopt corresponding starting strategies by real-time detection of the motor speed. For example, if the initial speed of the motor is less than a certain speed threshold, the motor is first dragged to a certain speed before switching to closed-loop control. If the initial speed is greater than the speed threshold, the motor is first braked to reduce its speed before switching to open-loop starting. The speed of this type of motor can usually meet customer needs at a few thousand rpm. However, in new fan applications such as vacuum cleaners and hair dryers, the required speed is as high as hundreds of thousands rpm. The potential in the motor stator winding is high for a period of time after shutdown. At the same time, due to the presence of cogging torque in the permanent magnet motor, the motor output torque will be less than the load torque, and the speed will fluctuate greatly. This situation will cause the current commutation to be incorrect after startup, and then trigger the overcurrent protection shutdown, making the downwind starting algorithm invalid.

[0035] Therefore, the problem of high-speed motor failure to start under downwind conditions needs to be solved urgently. High-speed motors generally refer to motors with speeds exceeding 10,000 r / min.

[0036] According to an embodiment of the present invention, a method for starting and controlling a motor is provided. Figure 1 FIG2 is a flow chart of an embodiment of the method of the present invention. The motor startup control method may include steps S110 to S130.

[0037] In step S110 , when the motor needs to be started, an enable signal of the motor is controlled to be equal to 1.

[0038] At step S120, when the motor enable signal is equal to 1, the motor speed is obtained, which is recorded as the current motor speed. The rotor position parameter of the motor at the current moment is obtained, which is recorded as the current rotor position parameter. The rotor position parameter is, for example, a rotor position signal.

[0039] In step S130 , the motor is controlled to start according to the current rotation speed of the motor and the current rotor position parameters of the motor.

[0040] In the related solutions, the downwind starting solutions in the field of wind turbines mostly adopt corresponding starting strategies by real-time detection of motor speed, such as: if the initial speed of the motor is less than a certain speed threshold, the motor is first dragged to a certain speed and then closed-loop control is switched on; if the initial speed is greater than the speed threshold, the motor is first braked to reduce its speed and then open-loop start is switched on. The solution of the present invention provides a starting control method for a high-speed motor. On the basis of setting a motor starting speed threshold, the rotor position parameters are identified, such as by using an internal counter of a main control chip to identify the rotor position parameters, and the speed and position sensor signal of the motor after power-on are detected in real time. When the speed is less than or equal to a certain speed (such as a motor with a maximum speed of 100krpm is decelerated to 6krpm after power-off) and the position sensor signal length is uniform (T1 and T2 have no obvious difference), the drive signal is output to the corresponding winding according to the rotor position to ensure that the motor can operate normally when starting downwind, and avoid the problem of incorrect commutation and starting failure caused by large jitter of the motor speed due to cogging torque.

[0041] Setting the motor starting speed threshold depends primarily on the starting current. Motor controllers typically include overcurrent protection, which triggers a shutdown when the starting current is too high. Different control schemes and controller parameter settings affect the starting current, so the speed threshold needs to be determined through multiple starting current measurements.

[0042] The rotor position signal length refers to the high and low level signals when the Hall position sensor signal is sent to the chip for relevant calculation. The length of the high and low level signals is identified by the chip's internal counter, that is, the length is the count value, not the signal directly fed back to the chip by the sensor.

[0043] Drive signals are output to the corresponding windings based on the rotor position. For example, for a single-phase motor, the motor drive topology is an H-bridge, consisting of four switches. The high and low periods of the HALL signal each account for half of the entire electrical cycle. When the HALL signal is high, the U-phase upper and V-phase lower switches are turned on. When the HALL signal is low, the U-phase lower and V-phase upper switches are turned on.

[0044] In some embodiments, the specific process of controlling the motor startup according to the current rotational speed of the motor and the current rotor position parameters of the motor in step S130 is described in the following exemplary embodiments.

[0045] The following combination Figure 2 The flowchart of an embodiment of controlling the motor startup according to the motor speed and rotor position parameters in the method of the present invention further illustrates the specific process of controlling the motor startup according to the motor speed and rotor position parameters in step S130, including: steps S210 to S230.

[0046] Step S210 , determining whether the current rotation speed of the motor is less than a set rotation speed threshold.

[0047] Step S220: If the current speed of the motor is greater than or equal to the speed threshold, the process returns after a delay of a first set time period to continue determining whether the current speed of the motor is less than the set speed threshold.

[0048] Step S230: If the current rotational speed of the motor is less than the rotational speed threshold, the motor is controlled to start according to the current rotor position parameter of the motor.

[0049] Considering that the high-speed motor still has a high speed for a period of time after power failure, the rotation of the motor will form a back electromotive force proportional to the speed in the winding. If the power is turned on again at this time, due to the starting excitation voltage, the power tube conduction voltage drop and the winding resistance R sare relatively small, and a relatively large current (much larger than the normal operating current) will be formed in the winding at the moment of starting. Therefore, the solution of the present invention provides a starting control method for a high-speed motor, which sets a starting speed threshold when starting with the wind at a high speed, and starts the motor when the motor enable signal is turned on and the starting speed is less than or equal to the threshold, thereby avoiding the motor from triggering overcurrent protection shutdown due to excessive starting current, and solving the problem of motor shutdown caused by triggering overcurrent protection after the high-speed motor is started with the wind. In this way, by setting the speed threshold, it is ensured that the high-speed motor can avoid triggering overcurrent protection by detecting the speed in real time after starting with the wind.

[0050] When the motor starts with the wind at high speed, Figure 6 As shown in (a), the winding coil cuts the rotor magnetic field to generate a back electromotive force proportional to the speed, and the motor starting excitation voltage is small, the power tube conduction voltage drop is approximately 0, and the winding resistance R s Generally, it is very small, so the current flowing through the winding will increase rapidly at the moment of starting. When the motor starting threshold is set high, the large current will increase the voltage across the current sampling resistor of the control board, such as Figure 6 As shown in (b), this signal passes through a software / hardware amplifier and is then input to the comparator's non-inverting terminal, CMPIN+. When CMPIN+ exceeds the overcurrent protection threshold, CMPIN-, at the comparator's inverting terminal, the comparator's output, CMPOUT, is high, triggering the hardware overcurrent protection function. For example, when the comparator's output, CMPOUT, is high, it triggers an MCU comparator interrupt, immediately initiating the overcurrent protection routine and causing the motor to fail to start with a tailwind. Therefore, a reasonable starting speed threshold must be set in the high-speed range to ensure a proper tailwind start of the motor.

[0051] In some embodiments, the specific process of controlling the motor startup according to the current rotor position parameters of the motor in step S230 is described in the following exemplary embodiments.

[0052] The following combination Figure 3 The flowchart of an embodiment of controlling the motor startup according to the rotor position parameters in the method of the present invention further illustrates the specific process of controlling the motor startup according to the rotor position parameters in step S230, including: steps S310 to S330.

[0053] Step S310: Determine whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the last moment, wherein the rotor position parameter of the motor at the last moment is the rotor position parameter of the motor at the last moment, which is recorded as the rotor position parameter at the last moment.

[0054] In step S320, if the current rotor position parameter of the motor is not equal to the rotor position parameter of the motor at the previous moment, the process returns after a second set delay to continue determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment.

[0055] Step S330 : If the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment, the motor is controlled to enter a preset starting subroutine to implement starting control of the motor.

[0056] Figure 7 The waveform diagrams of the HALL signal (i.e., Hall signal) and excitation voltage when the motor is running under different working conditions are shown below. (a) is a waveform diagram when the motor is running at a constant speed, and (b) is a waveform diagram when the speed fluctuates. Figure 7 In the example shown, α is the lead angle, that is, the excitation voltage leads the phase current.

[0057] Figure 8 It is the waveform diagram of the HALL signal in the low speed section. Figure 8 In the example shown, T is the HALL signal period, T1 is the upper half period, T2 is the lower half period, box 1 represents the starting speed threshold, and box 2 is a schematic diagram of the uneven HALL signal length caused by speed jitter (i.e., there is a significant difference between T1 and T2).

[0058] Taking into account the inherent cogging torque in the permanent magnet motor and the periodic change of the electromagnetic torque during the rotation process, when the motor loses power to a medium or low speed, its output torque and load torque will lose balance, causing the speed to jitter significantly and the position sensor signal length to be uneven. If the power is turned on again at this time, due to the discrete characteristics of the controller MCU, it uses the position sensor signal at the current sampling moment to estimate the commutation signal at the next sampling moment, which is very likely to cause a commutation error. Therefore, the solution of the present invention identifies the length of the position sensor signal when starting with the wind in the medium and low speed section, and starts the motor when the length of the position sensor signal is uniform, thereby avoiding the motor triggering the overcurrent protection shutdown due to a commutation error, and solves the problem of misidentification of the position sensor signal caused by the speed jitter caused by the cogging torque when the high-speed motor is started with the wind, and then the problem of startup failure. In this way, by identifying the length of the position sensor signal (such as the Hall signal of the Hall sensor), the high-speed motor can obtain the correct commutation signal when starting with the wind, avoiding the problem of startup failure caused by a commutation error.

[0059] Since the solution of the present invention involves a high-speed motor using a permanent magnet motor, its rotor is composed of permanent magnets and an iron core. Even if the stator winding is not energized, there will be interaction between the permanent magnets and the iron core to generate cogging torque. When the motor is started with the wind at a low speed, the motor will be under the influence of the electromagnetic torque (which changes periodically) generated by the combined magnetic field of the stator and rotor, the cogging torque and the load torque. The motor output torque will be less than the load torque, which will cause the high-speed motor to have speed jitter when it is decelerated to a low speed after power failure. The HALL signal waveform is as follows: Figure 7 As shown in (b), if the starting speed threshold is set at Figure 8 In the middle frame 2, the motor is started after the software determines that the motor enable signal is turned on and the starting speed is less than or equal to the speed threshold. Since the motor control system is essentially a computer control system, the control command signals are all discrete quantities. It uses the overly wide / narrow HALL signal at the current moment to estimate the commutation signal acting on the motor winding at the next moment, which will cause incorrect current commutation after startup, thereby triggering overcurrent protection shutdown and speed startup failure.

[0060] Of course, in non-permanent magnet motor applications, if the speed jitter triggers the overcurrent protection shutdown, the failure of tailwind start can still be avoided by identifying whether the HALL signal length is uniform.

[0061] Therefore, the improved technical solution of the present invention sets a belt speed starting speed threshold and uses an algorithm to determine whether the length of the HALL signal is uniform to achieve motor belt speed starting. When the motor start signal is enabled, the initial motor speed is less than or equal to the speed threshold, and the HALL signal length is uniform, the motor can start normally. Specifically, the algorithm compares the length of the HALL signal at the current moment with that at the previous moment to determine whether they are equal.

[0062] The current rotor position parameters of the motor and the rotor position parameters of the motor at the previous moment include the rotor position signal length. Hall effect sensors are commonly used in motor control systems to detect the motor's rotor position. The signals fed back from the Hall effect IC to the main control chip are high and low level signals. In the embodiments of the present invention, expressions such as "rotor position signal," "Hall effect position signal," "Hall effect sensor signal," and "position sensor signal" all refer to the signals fed back from the Hall effect IC to the main control chip.

[0063] Figure 9 FIG. 1 is a flow chart of the improved starting method for the motor of the present invention. Figure 9 As shown, the solution of the present invention provides an improved starting method for a motor, comprising:

[0064] Step 1: Set the motor enable signal to 1.

[0065] Motor enable, in simple terms, is an "allow" signal, and feed enable is a signal that allows feeding, which means that the motor can only rotate when the feed enable signal is valid.

[0066] The solution of the present invention is mainly aimed at high-speed fan applications. The fan control system is mostly a speed regulation system (inner loop current loop, outer loop speed loop). In applications such as vacuum cleaners and hair dryers, the motor speed is high (tens of thousands of rpm); the electronic control system in machine tools is generally a servo system (current loop, speed loop, position loop), and the motor speed is relatively low, so it can be started normally using a conventional startup control algorithm.

[0067] Step 2: Determine whether the current motor speed is less than the set speed threshold. If so, proceed to step 3; otherwise, continue to step 2.

[0068] Step 3: Determine whether the current HALL signal length is equal to the HALL signal length at the previous moment: if so, enter the startup subroutine; otherwise, continue to execute step 3 after a delay.

[0069] In the solution of the present invention, when the motor is started with a tailwind in a high-speed section, the motor starts when the speed is less than or equal to the starting speed threshold. When the motor is started with a tailwind in a low-speed section, the motor starts when the length of the rotor position signal is uniform. Compared with related solutions, the solution of the present invention does not require the setting of multiple speed thresholds, and the algorithm structure is simpler. It also avoids the problem of tailwind start-up failure caused by speed jitter by identifying whether the length of the rotor position signal is uniform. The solution is simpler and can effectively avoid the problem of tailwind start-up failure caused by speed jitter triggering overcurrent protection. The algorithm is easy to implement and has significant results.

[0070] The technical solution of this embodiment detects the motor speed and position sensor signal in real time after power-on by setting a motor startup speed threshold and identifying the length of the rotor position signal. When the speed is less than or equal to a certain speed and the position sensor signal length is uniform, a drive signal is output to the corresponding winding based on the rotor position to ensure normal operation of the motor during a downwind start. Thus, by setting a motor startup speed threshold and identifying the length of the rotor position signal, normal operation of the motor during a downwind start is ensured.

[0071] According to an embodiment of the present invention, a motor startup control device corresponding to the motor startup control method is also provided. Figure 4 FIG2 is a schematic structural diagram of an embodiment of the device of the present invention. The motor start control device may include: an acquisition unit 102 and a control unit 104 .

[0072] The control unit 104 is configured to control the motor's enable signal to be equal to 1 when the motor needs to be started. The specific functions and processing of the control unit 104 are shown in step S110 .

[0073] The acquisition unit 102 is configured to acquire the motor speed, which is recorded as the current motor speed, when the motor enable signal is equal to 1. The acquisition unit 102 is configured to acquire the motor rotor position parameter at the current moment, which is recorded as the current rotor position parameter. The specific functions and processing of the acquisition unit 102 are described in step S120.

[0074] The control unit 104 is further configured to control the motor to start according to the current speed of the motor and the current rotor position parameter of the motor. The specific functions and processing of the control unit 104 are also shown in step S130.

[0075] In the related solutions, the downwind starting solutions in the field of wind turbines mostly adopt corresponding starting strategies by real-time detection of motor speed, such as: if the initial speed of the motor is less than a certain speed threshold, the motor is first dragged to a certain speed and then closed-loop control is switched on; if the initial speed is greater than the speed threshold, the motor is first braked to reduce its speed and then open-loop start is switched on. The solution of the present invention provides a starting control device for a high-speed motor. On the basis of setting a motor starting speed threshold, the device identifies the rotor position parameters, such as identifying the rotor position parameters through the internal counter of the main control chip, and performs real-time detection of the speed and position sensor signal after the motor is powered on. When the speed is less than or equal to a certain speed (such as a motor with a maximum speed of 100krpm is powered off and slowed down to 6krpm) and the position sensor signal length is uniform (T1 and T2 have no obvious difference), the drive signal is output to the corresponding winding according to the rotor position to ensure that the motor can operate normally when it is started downwind, and avoid the problem of incorrect commutation and starting failure caused by large jitter of the motor speed due to the cogging torque.

[0076] Drive signals are output to the corresponding windings based on the rotor position. For example, for a single-phase motor, the motor drive topology is an H-bridge, consisting of four switches. The high and low periods of the HALL signal each account for half of the entire electrical cycle. When the HALL signal is high, the U-phase upper and V-phase lower switches are turned on. When the HALL signal is low, the U-phase lower and V-phase upper switches are turned on.

[0077] In some embodiments, the control unit 104 controls the motor to start according to the current speed of the motor and the current rotor position parameter of the motor, including:

[0078] The control unit 104 is further configured to determine whether the current speed of the motor is less than a set speed threshold. The specific functions and processing of the control unit 104 are also shown in step S210.

[0079] The control unit 104 is further configured to, if the current speed of the motor is greater than or equal to the speed threshold, return after a first set delay to continue determining whether the current speed of the motor is less than the set speed threshold. The specific functions and processing of the control unit 104 are further described in step S220.

[0080] The control unit 104 is further configured to control the motor to start according to the current rotor position parameter of the motor if the current speed of the motor is less than the speed threshold. The specific functions and processing of the control unit 104 are also shown in step S230.

[0081] Considering that the high-speed motor still has a high speed for a period of time after power failure, the rotation of the motor will form a back electromotive force proportional to the speed in the winding. If the power is turned on again at this time, due to the starting excitation voltage, the power tube conduction voltage drop and the winding resistance R s are relatively small, and a relatively large current (much larger than the normal operating current) will be formed in the winding at the moment of starting. Therefore, the solution of the present invention provides a starting control device for a high-speed motor, which sets a starting speed threshold when starting with the wind at a high speed, and starts the motor when the motor enable signal is turned on and the starting speed is less than or equal to the threshold, thereby avoiding the motor from triggering overcurrent protection shutdown due to excessive starting current, and solving the problem of motor shutdown caused by triggering overcurrent protection after the high-speed motor is started with the wind. In this way, by setting the speed threshold, it is ensured that the high-speed motor can avoid triggering overcurrent protection by detecting the speed in real time after starting with the wind.

[0082] When the motor starts with the wind at high speed, Figure 6 As shown in (a), the winding coil cuts the rotor magnetic field to generate a back electromotive force proportional to the speed, and the motor starting excitation voltage is small, the power tube conduction voltage drop is approximately 0, and the winding resistance R s Generally, it is very small, so the current flowing through the winding will increase rapidly at the moment of starting. When the motor starting threshold is set high, the large current will increase the voltage across the current sampling resistor of the control board, such as Figure 6 As shown in (b), this signal passes through a software / hardware amplifier and is then input to the comparator's non-inverting terminal, CMPIN+. When CMPIN+ exceeds the overcurrent protection threshold, CMPIN-, at the comparator's inverting terminal, the comparator's output, CMPOUT, is high, triggering the hardware overcurrent protection function. For example, when the comparator's output, CMPOUT, is high, it triggers an MCU comparator interrupt, immediately initiating the overcurrent protection routine and causing the motor to fail to start with a tailwind. Therefore, a reasonable starting speed threshold must be set in the high-speed range to ensure a proper tailwind start of the motor.

[0083] In some embodiments, the control unit 104 controls the motor to start according to the current rotor position parameter of the motor, including:

[0084] The control unit 104 is further configured to determine whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at a previous moment. The rotor position parameter of the motor at a previous moment is the rotor position parameter of the motor at the previous moment, which is recorded as the rotor position parameter at the previous moment. The specific functions and processing of the control unit 104 are further described in step S310.

[0085] The control unit 104 is further configured to, if the current rotor position parameter of the motor is not equal to the rotor position parameter of the motor at a previous moment, return after a second set delay to continue determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at a previous moment. The specific functions and processing of the control unit 104 are further described in step S320.

[0086] The control unit 104 is further configured to control the motor to enter a preset startup subroutine if the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at a previous moment, thereby controlling the motor to start the motor. The specific functions and processing of the control unit 104 are further described in step S330.

[0087] Figure 7 The waveform diagrams of the HALL signal (i.e., Hall signal) and excitation voltage when the motor is running under different working conditions are shown below. (a) is a waveform diagram when the motor is running at a constant speed, and (b) is a waveform diagram when the speed fluctuates. Figure 7 In the example shown, α is the lead angle, that is, the excitation voltage leads the phase current.

[0088] Figure 8 It is the waveform diagram of the HALL signal in the low speed section. Figure 8 In the example shown, T is the HALL signal period, T1 is the upper half period, T2 is the lower half period, box 1 represents the starting speed threshold, and box 2 is a schematic diagram of the uneven HALL signal length caused by speed jitter (i.e., there is a significant difference between T1 and T2).

[0089] Taking into account the inherent cogging torque in the permanent magnet motor and the periodic change of the electromagnetic torque during the rotation process, when the motor loses power to a medium or low speed, its output torque and load torque will lose balance, causing the speed to jitter significantly and the position sensor signal length to be uneven. If the power is turned on again at this time, due to the discrete characteristics of the controller MCU, it uses the position sensor signal at the current sampling moment to estimate the commutation signal at the next sampling moment, which is very likely to cause a commutation error. Therefore, the solution of the present invention identifies the length of the position sensor signal when starting with the wind in the medium and low speed section, and starts the motor when the length of the position sensor signal is uniform, thereby avoiding the motor triggering the overcurrent protection shutdown due to a commutation error, and solves the problem of misidentification of the position sensor signal caused by the speed jitter caused by the cogging torque when the high-speed motor is started with the wind, and then the problem of startup failure. In this way, by identifying the length of the position sensor signal (such as the Hall signal of the Hall sensor), the high-speed motor can obtain the correct commutation signal when starting with the wind, avoiding the problem of startup failure caused by a commutation error.

[0090] Since the solution of the present invention involves a high-speed motor using a permanent magnet motor, its rotor is composed of permanent magnets and an iron core. Even if the stator winding is not energized, there will be interaction between the permanent magnets and the iron core to generate cogging torque. When the motor is started with the wind at a low speed, the motor will be under the influence of the electromagnetic torque (which changes periodically) generated by the combined magnetic field of the stator and rotor, the cogging torque and the load torque. The motor output torque will be less than the load torque, which will cause the high-speed motor to have speed jitter when it is decelerated to a low speed after power failure. The HALL signal waveform is as follows: Figure 7 As shown in (b), if the starting speed threshold is set at Figure 8 In the middle frame 2, the motor is started after the software determines that the motor enable signal is turned on and the starting speed is less than or equal to the speed threshold. Since the motor control system is essentially a computer control system, the control command signals are all discrete quantities. It uses the overly wide / narrow HALL signal at the current moment to estimate the commutation signal acting on the motor winding at the next moment, which will cause incorrect current commutation after startup, thereby triggering overcurrent protection shutdown and speed startup failure.

[0091] Of course, in non-permanent magnet motor applications, if the speed jitter triggers the overcurrent protection shutdown, the failure of tailwind start can still be avoided by identifying whether the HALL signal length is uniform.

[0092] Therefore, the improved technical solution of the present invention sets a belt speed starting speed threshold and uses an algorithm to determine whether the length of the HALL signal is uniform to achieve motor belt speed starting. When the motor start signal is enabled, the initial motor speed is less than or equal to the speed threshold, and the HALL signal length is uniform, the motor can start normally. Specifically, the algorithm compares the length of the HALL signal at the current moment with that at the previous moment to determine whether they are equal.

[0093] The current rotor position parameter of the motor and the rotor position parameter of the motor at the previous moment include: a rotor position signal length.

[0094] Figure 9 Schematic diagram of the program flow of the improved starting device of the motor of the present invention. Figure 9 As shown, the solution of the present invention provides an improved starting device for a motor, comprising:

[0095] Step 1: Set the motor enable signal to 1.

[0096] Motor enable, in layman's terms, is a "permit" signal. Feed enable is also a signal that allows feed, meaning the motor can only rotate when the feed enable signal is valid. Typical CNC systems connect the motor's feed enable signal in series with the emergency stop switch and travel limit switches. When the emergency stop switch is pressed or the motor exceeds its travel range, the feed enable signal is disconnected, preventing the motor from continuing to rotate, thereby protecting the machine tool from operating within a safe range.

[0097] Step 2: Determine whether the current motor speed is less than the set speed threshold. If so, proceed to step 3; otherwise, continue to step 2.

[0098] Step 3: Determine whether the current HALL signal length is equal to the HALL signal length at the previous moment: if so, enter the startup subroutine; otherwise, continue to execute step 3 after a delay.

[0099] In the solution of the present invention, when the motor is started with a tailwind in a high-speed section, the motor starts when the speed is less than or equal to the starting speed threshold. When the motor is started with a tailwind in a low-speed section, the motor starts when the length of the rotor position signal is uniform. Compared with related solutions, the solution of the present invention does not require the setting of multiple speed thresholds, and the algorithm structure is simpler. It also avoids the problem of tailwind start-up failure caused by speed jitter by identifying whether the length of the rotor position signal is uniform. The solution is simpler and can effectively avoid the problem of tailwind start-up failure caused by speed jitter triggering overcurrent protection. The algorithm is easy to implement and has significant results.

[0100] Since the processing and functions implemented by the device of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0101] By adopting the technical solution of the present invention, the speed and position sensor signal of the motor after power-on are detected in real time by identifying the length of the rotor position signal on the basis of setting the motor starting speed threshold. When the speed is less than or equal to a certain speed and the position sensor signal length is uniform, the drive signal is output to the corresponding winding according to the rotor position to ensure that the motor can operate normally when started with a tailwind, ensuring that the high-speed motor can avoid triggering overcurrent protection by detecting the speed in real time after starting with a tailwind.

[0102] According to an embodiment of the present invention, a motor corresponding to a starting control device for the motor is further provided. The motor may include: the starting control device for the motor described above.

[0103] Since the processing and functions implemented by the motor of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0104] By adopting the technical solution of the present invention, the speed and position sensor signal of the motor after power-on are detected in real time by identifying the length of the rotor position signal on the basis of setting the motor starting speed threshold. When the speed is less than or equal to a certain speed and the position sensor signal length is uniform, a drive signal is output to the corresponding winding according to the rotor position to ensure that the motor can operate normally when starting with a tailwind, avoiding the problem of incorrect commutation and starting failure caused by large jitter of the motor speed due to the slot torque.

[0105] According to an embodiment of the present invention, a storage medium corresponding to the motor startup control method is also provided, wherein the storage medium includes a stored program, wherein when the program is run, the device where the storage medium is located is controlled to execute the motor startup control method described above.

[0106] Since the processing and functions implemented by the storage medium of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0107] By adopting the technical solution of the present invention, the speed and position sensor signal of the motor after power-on are detected in real time by identifying the length of the rotor position signal on the basis of setting the motor starting speed threshold. When the speed is less than or equal to a certain speed and the position sensor signal length is uniform, the drive signal is output to the corresponding winding according to the rotor position to ensure that the motor can operate normally when starting with a tailwind, avoiding the problem of starting failure caused by commutation errors.

[0108] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0109] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims.

Claims

1. A motor startup control method, characterized in that: include: When the motor needs to be started, the enable signal for controlling the motor is equal to 1; When the enable signal of the motor is equal to 1, obtaining the rotation speed of the motor, which is recorded as the current rotation speed of the motor; Obtaining a rotor position parameter of the motor at a current moment, recorded as a current rotor position parameter; The current rotor position parameters of the motor include: rotor position signal length; Controlling the start of the motor according to the current speed of the motor and the current rotor position parameter of the motor; and ensuring normal operation of the motor when starting with a tailwind by identifying the length of the rotor position signal based on a set speed threshold; The step of controlling the motor to start according to the current rotor position parameter of the motor includes: Determining whether a current rotor position parameter of the motor is equal to a rotor position parameter of the motor at a previous moment; wherein the rotor position parameter of the motor at a previous moment is a rotor position parameter of the motor at a previous moment, recorded as the rotor position parameter at a previous moment; If the current rotor position parameter of the motor is not equal to the rotor position parameter of the motor at the previous moment, returning after a second set time to continue determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment; If the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment, the motor is controlled to enter a preset starting subroutine to implement starting control of the motor.

2. The motor startup control method according to claim 1, characterized in that: Controlling the motor to start according to the current speed of the motor and the current rotor position parameter of the motor includes: Determining whether the current speed of the motor is less than a set speed threshold; If the current speed of the motor is greater than or equal to the speed threshold, the process returns after a first set delay to continue determining whether the current speed of the motor is less than the set speed threshold; If the current rotational speed of the motor is less than the rotational speed threshold, the motor is controlled to start according to the current rotor position parameter of the motor.

3. The motor startup control method according to claim 1, characterized in that: in, The rotor position parameters of the motor at the last moment include: the rotor position signal length.

4. A motor starting control device, characterized in that: include: a control unit, configured to control an enable signal of the motor to be equal to 1 when the motor needs to be started; an acquiring unit, configured to acquire a rotational speed of the motor when an enable signal of the motor is equal to 1, and record the obtained rotational speed as a current rotational speed of the motor; Obtaining a rotor position parameter of the motor at a current moment, recorded as a current rotor position parameter; The current rotor position parameters of the motor include: rotor position signal length; The control unit is further configured to control the start of the motor according to the current speed of the motor and the current rotor position parameter of the motor; and to ensure that the motor can operate normally when started with a tailwind by identifying the length of the rotor position signal based on a set speed threshold; The control unit controls the motor to start according to the current rotor position parameter of the motor, including: Determining whether a current rotor position parameter of the motor is equal to a rotor position parameter of the motor at a previous moment; wherein the rotor position parameter of the motor at a previous moment is a rotor position parameter of the motor at a previous moment, recorded as the rotor position parameter at a previous moment; If the current rotor position parameter of the motor is not equal to the rotor position parameter of the motor at the previous moment, returning after a second set time to continue determining whether the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment; If the current rotor position parameter of the motor is equal to the rotor position parameter of the motor at the previous moment, the motor is controlled to enter a preset starting subroutine to implement starting control of the motor.

5. The motor starting control device according to claim 4, characterized in that: The control unit controls the motor to start according to the current rotation speed of the motor and the current rotor position parameter of the motor, including: Determining whether the current speed of the motor is less than a set speed threshold; If the current speed of the motor is greater than or equal to the speed threshold, the process returns after a first set delay to continue determining whether the current speed of the motor is less than the set speed threshold; If the current rotational speed of the motor is less than the rotational speed threshold, the motor is controlled to start according to the current rotor position parameter of the motor.

6. The motor starting control device according to claim 4, characterized in that: in, The rotor position parameters of the motor at the last moment include: the rotor position signal length.

7. A motor, characterized in that: include: The starting control device for a motor according to any one of claims 4 to 6.

8. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is executed, the device where the storage medium is located is controlled to execute the motor startup control method according to any one of claims 1 to 3.

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