Control method of permanent magnet synchronous motor operation based on sensorless vector control

Abstract

The present invention discloses a control method for the operation of a permanent magnet synchronous motor based on sensorless vector control, which is characterized in that: when the motor is running, upon receiving a shutdown control signal sent by an external device, a microprocessor MCU does not directly block PWM pulse processing on an inverter, but continues to output pulses to the inverter for speed reduction processing, and constantly detects the control signal sent by the external device; during the speed reduction processing, when the real-time operating speed Vi of the motor is greater than or equal to a set speed Vref and the microprocessor MCU re-obtains a new starting control signal, the motor is controlled to move from the current real-time operating speed Vi to a target speed V or a target torque T corresponding to the re-obtained new starting control signal; when the real-time operating speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks PWM pulse processing; after the speed reduction processing, the microprocessor MCU is shut down and the pulses are blocked, so that the torque of the motor pre-positioning can smoothly stop the load, avoid jitter, setbacks, noise, etc., reduce current impact, and extend the life of the motor.

Description

Technical field:

[0001] The invention relates to a method for controlling the operation of a permanent magnet synchronous motor based on sensorless vector control. Background technology:

[0002] Permanent magnet synchronous motors with Hall sensors constantly sense rotor position and speed, ensuring stable and reliable control. However, the introduction of Hall sensors increases the motor's size and cost. Furthermore, the addition of Hall sensors requires additional wiring, which can easily cause interference and reduce motor performance. Furthermore, Hall sensors require precise installation, significantly increasing the complexity of the motor's production process. Therefore, adopting Hall sensor-free control strategies is highly practical. Currently, many manufacturers are gradually promoting Hall sensor-free permanent magnet synchronous motors, addressing the drawbacks of Hall sensor-based systems and significantly expanding the application range of permanent magnet synchronous motors. However, information such as the motor's rotor position is estimated using complex algorithms, placing high demands on the reliability of the control algorithms.

[0003] Permanent magnet synchronous motor control based on sensorless vector control generally adopts pre-positioning to improve starting torque, especially for large inertia loads. However, the pre-positioning method enables the permanent magnet synchronous motor to continue rotating for a long time when the operation control signal from the external device is disconnected (equivalent to shutdown). If the operation start control signal is restored during this process, it is equivalent to restarting the permanent magnet synchronous motor while it is still rotating, which is very likely to trigger overcurrent or abnormal conditions such as setbacks and noise. In extreme cases, components may be damaged. To solve the above problems, the current practices are: 1. Wait until the load stops rotating completely before starting the permanent magnet synchronous motor. However, due to the large inertia of the load, it takes a long time to stop completely. The user experience is extremely bad; 2. Directly turn off the pulse. After the operation control signal sent by the external device is restored, it will be started directly in the pre-positioning mode regardless of the current load status. In this way, after turning off the pulse, due to the large load inertia, the permanent magnet synchronous motor has to continue to rotate. If it is started in the pre-positioning mode when the rotation speed is high, an impact voltage will be generated, which can easily damage the switching device. At the same time, if the permanent magnet synchronous motor is started directly from the pre-position when rotating at high speed, it will cause a large current impact, and the permanent magnet synchronous motor will have problems such as jitter, jerking, and noise. In this way, it is necessary to increase the hardware redundancy design, but the problems such as jitter, jerking, and noise can never be completely solved, and there is also the possibility of the permanent magnet synchronous motor failing to start. Summary of the invention:

[0004] The purpose of the present invention is to provide a control method for the operation of a permanent magnet synchronous motor based on sensorless vector control, which can solve the problem in the prior art that when the permanent magnet synchronous motor receives a shutdown control signal from an external device during operation, the microprocessor MCU directly blocks the pulse output and obtains a new start control signal to start the motor directly in a pre-positioning manner regardless of the current load state. In this approach, after blocking the pulse, due to the large load inertia, the permanent magnet synchronous motor has to continue to rotate. If the motor is started at a high rotation speed, an impact voltage will be generated, which is very likely to damage the switching device. At the same time, if the permanent magnet synchronous motor is started directly from the pre-position when it is rotating at high speed, it will cause a large current impact, and the permanent magnet synchronous motor will have technical problems such as jitter, setbacks, and noise.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] The control method of the permanent magnet synchronous motor operation based on sensorless vector control is characterized in that: when the motor is running, upon receiving a shutdown control signal from an external device, the microprocessor MCU does not directly block PWM pulse processing on the inverter, but continues to output pulses to the inverter for speed reduction processing, and constantly detects the control signal sent by the external device. During the speed reduction processing, when the real-time operating speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new starting control signal, the motor is controlled to move from the current real-time operating speed Vi to the target speed V or target torque T corresponding to the regained new starting control signal; when the real-time operating speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks PWM pulse processing.

[0007] When the real-time running speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing, and the motor continues to rotate with inertia and constantly detects the control signal sent by the external device. If the microprocessor MCU regains a new start control signal at this time, the microprocessor MCU will turn on all the lower bridge switches of the inverter, and the motor will enter the energy consumption braking mode for a duration of t1. Then the microprocessor MCU will energize the coil windings of each phase of the motor in a specific sequence to lock the rotor position for a duration of t2. Then it will regain a new start control signal to control the motor to enter the sensorless starting operation state again.

[0008] The above-mentioned motor is a three-phase permanent magnet synchronous motor, including coil windings U, V, and W. During the process of blocking the PWM pulse processing by the microprocessor MCU, if the microprocessor MCU regains a new start control signal at this time, the microprocessor MCU turns on the three lower bridge switches Q4, Q5, and Q6 of the inverter, and the motor enters the energy consumption braking mode for a duration of t1. Then, the microprocessor MCU will energize the three-phase coil windings U, V, and W of the motor in a specific order to lock the rotor position for a duration of t2.

[0009] When the motor receives a stop control signal from an external device, the microprocessor MCU controls the motor to decelerate. During the deceleration process, a timing time t3 is set at the same time. The microprocessor MCU starts timing from the receipt of the stop control signal. When the duration of the stop control signal is greater than or equal to the timing time t3, the microprocessor MCU forcibly blocks the PWM pulse signal.

[0010] The above-mentioned set rotation speed Vref is a value in the range of 200 rpm to 400 rpm.

[0011] The above-mentioned movement of the motor from the real-time running speed Vi to the speed V corresponding to the regained gear signal refers to accelerating or decelerating at a certain step distance V0 on the basis of the real-time running speed Vi to move closer to the speed V.

[0012] The above-mentioned certain step size V0 is determined according to the rotational inertia of the motor and the difference between the real-time running speed Vi and the speed V corresponding to the regained gear signal.

[0013] Compared with the prior art, the present invention has the following effects:

[0014] 1) Through the technical solution of the present invention, when a shutdown control signal is received from an external device, the microprocessor MCU does not directly block the PWM pulse processing of the inverter, but continues to output pulses to the inverter for deceleration processing, and constantly detects the control signal sent by the external device. During the deceleration process, when the real-time operating speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new starting control signal, the motor is controlled to move from the current real-time operating speed Vi to the target speed V or target torque T corresponding to the regained new starting control signal; when the real-time operating speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing. In large inertia load applications, the permanent magnet synchronous motor can quickly respond and start again smoothly when a new starting control signal is restored, when starting and stopping frequently, when switching gears, etc., to avoid abnormal conditions such as jitter, setbacks, and noise, and can reduce current shock, effectively protect switching devices, extend the service life of the permanent magnet synchronous motor, and greatly improve user experience;

[0015] 2) Other advantages of the present invention are described in detail in the embodiment section. Description of the drawings:

[0016] Figure 1 is a three-dimensional diagram of a permanent magnet synchronous motor provided in Embodiment 1 of the present invention;

[0017] Figure 2 is a three-dimensional diagram of a motor controller for a permanent magnet synchronous motor provided in Embodiment 1 of the present invention;

[0018] Figure 3 is a cross-sectional view of a permanent magnet synchronous motor provided in Embodiment 1 of the present invention;

[0019] Figure 4 This is a schematic diagram of the control principle of the permanent magnet synchronous motor controller provided in the first embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of the principle of a position sensorless vector controlled permanent magnet synchronous motor provided in Example 1 of the present invention.

[0021] Figure 6 1 is a diagram showing the relationship between various coordinate systems for the vector control of a permanent magnet synchronous motor provided in the first embodiment of the present invention;

[0022] Figure 7 This is a principle block diagram of a motor controller for a permanent magnet synchronous motor provided in the first embodiment of the present invention;

[0023] Figure 8 This is a control flow chart of the permanent magnet synchronous motor provided in the first embodiment of the present invention;

[0024] Figure 9 Schematic diagram of the connection between the permanent magnet synchronous motor and external equipment according to the first embodiment of the present invention;

[0025] Figure 10 This is a flow chart of a method for controlling the operation of a permanent magnet synchronous motor based on sensorless vector control provided in the first embodiment of the present invention;

[0026] Figure 11 This is a control flow chart for re-obtaining a new start control signal during the pulse blocking process in the first embodiment of the present invention;

[0027] Figure 12 This is a schematic diagram of the connection between a permanent magnet synchronous motor and external equipment according to a second embodiment of the present invention;

[0028] Figure 13 This is a circuit block diagram of a motor controller for a permanent magnet synchronous motor according to a second embodiment of the present invention. Specific implementation method:

[0029] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0030] like Figures 1 to 3 As shown, it is assumed that the present invention is a three-phase permanent magnet synchronous motor, which consists of a motor controller 2 and a motor monomer 1. The motor monomer 1 includes a stator assembly 12, a rotor assembly 13 and a housing assembly 11. The stator assembly 13 is installed on the housing assembly 11, and the rotor assembly 13 is sleeved on the inner side or the outer side of the stator assembly 12. The motor controller 2 includes a control box 22 and a control circuit board 21 installed in the control box 22. The control circuit board 21 generally includes a power supply circuit, a microprocessor MCU, a bus voltage detection circuit, and an inverter. The power supply circuit supplies power to each circuit part. The bus voltage detection circuit inputs the DC bus voltage Uabc to the microprocessor MCU. The microprocessor MCU controls the inverter. The inverter controls the on and off of the coil windings of each phase of the stator assembly 12. The stator assembly 12 includes a stator core and three-phase coil windings U, V, and W.

[0031] Assume that the phase current detection circuit of a three-phase brushless DC permanent magnet synchronous motor inputs the phase currents ia and ib of two of the stator coil windings into a microprocessor (MCU). Based on the relationship between ia, ib, and ic, the phase current ic can be calculated. The MCU can also calculate the q-axis current iq from these phase currents ia, ib, and ic. This information is documented in textbooks and will not be described here. The AC input (AC INPUT) passes through a full-wave rectifier circuit composed of diodes D7, D8, D9, and D10, and outputs a DC bus voltage Vbus at one end of capacitor C1. This DC bus voltage Vbus is related to the input AC voltage. The MCU then inputs a PWM signal to the inverter. The inverter consists of electronic switches Q1, Q2, Q3, Q4, Q5, and Q6. The control terminals of these switches are controlled by six PWM pulse signals (P1, P2, P3, P4, P5, and P6) output by the MCU, respectively. There are three upper bridge switching tubes Q1, Q2, Q3 and three lower bridge switching tubes Q4, Q5, Q6.

[0032] exist Figure 4The microprocessor MCU has multiple gear input signals, Tap1, Tap2, ..., Tapn, where n is an integer. Each gear input signal is connected to a gear detection circuit via a switch. The microprocessor MCU uses these gear detection circuits to detect each gear input signal. In the figure, the gear input signals Tap1, Tap2, ..., Tapn correspond to switches K1, K2, ..., Kn, respectively. For example, when switch K1 is closed, the gear input signal Tap1 is detected by the gear detection circuit connected to it and then sent to the microprocessor MCU. The microprocessor MCU then controls the motor to operate at the set speed based on the motor speed corresponding to this gear signal. For example, the motor speed corresponding to gear input signal Tap1 is 700 rpm, the motor speed corresponding to gear input signal Tap2 is 800 rpm, the motor speed corresponding to gear input signal Tap3 is 900 rpm, and the motor speed corresponding to gear input signal Tapn is 1400 rpm. The motor's microprocessor (MCU) selects different speeds based on the various gear input signals, controlling the motor to operate at the speed corresponding to the gear input signal. When all gear input signals are deactivated (i.e., all switches are disconnected), the motor's microprocessor (MCU) blocks the pulse signal output, shutting off the inverter's electronic switches Q1, Q2, Q3, Q4, Q5, and Q6. This condition is known in the industry as a pulse-blocked shutdown.

[0033] In the case of multiple gear input signals, when all switches K1, K2...Kn are disconnected, all gear input signals Tap1, Tap2...Tapn are equivalent to being disconnected from the microprocessor MCU. The signal at this time can be called a shutdown control signal sent by an external device; when one of the switches K1, K2...Kn is closed, one of the gear input signals Tap1, Tap2...Tapn is input to the microprocessor MCU, which is equivalent to the microprocessor MCU regaining a new start control signal.

[0034] like Figure 5 As shown in the figure, the basic working principle of the position sensorless vector controlled permanent magnet synchronous motor is briefly described (the textbook has a detailed description). The permanent magnet synchronous motor is regarded as the result of the interaction between the rotating magnetic field of the stator and the rotating magnetic field of the rotor. There are two coordinate systems in the figure, one is the rotor rotating coordinate system dq axis; the other is the stator stationary coordinate system ABC coordinate system (which can be converted into a stationary coordinate system with αβ perpendicular to each other, see Figure 6 As shown); the rotor can be regarded as rotating at a speed wr due to the action of the excitation current if, and the stator can be regarded as rotating at a speed ws due to the action of the excitation current is. The resultant vector of the stator in the figure is S; according to the calculation formula of the electromagnetic torque:

[0035] Electromagnetic torque T = K × iq; where K is a coefficient and iq is the q-axis current component of vector S.

[0036] like Figure 6 As shown in the figure, the stator stationary coordinate system ABC is replaced by a mutually perpendicular coordinate system αβ. The stator stationary coordinate system is the coordinate system of αβ, and the rotor rotating coordinate system is the dq coordinate system. The angle between the αβ coordinate system and the dq coordinate system is θ.

[0037] like Figure 7 The figure shows the hardware control block diagram of the position sensorless vector controlled permanent magnet synchronous motor. Figure 8 This is a software flowchart for a sensorless vector-controlled permanent magnet synchronous motor. The microprocessor MCU calculates the q-axis current iq and d-axis current id based on the phase currents ia, ib, and ic, and uses the position and speed observer to estimate the real-time motor speed Vi. Assuming the motor's gear input signal selects the speed Vsp, the motor's microprocessor MCU controls the motor based on the selected speed Vsp. If the real-time speed Vi does not reach the selected speed Vsp, the torque iq_in is adjusted to increase or decrease the speed until the real-time speed Vi reaches the selected speed Vsp.

[0038] like Figure 9 、 Figure 10 and Figure 11 As shown in the figure, a control method for the operation of a permanent magnet synchronous motor based on sensorless vector control is provided. When the motor is running, it receives a shutdown control signal from an external device. The microprocessor MCU does not directly block the PWM pulse processing of the inverter, but continues to output pulses to the inverter for speed reduction processing, and constantly detects the control signal sent by the external device. During the speed reduction processing, when the real-time operating speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new starting control signal, the motor is controlled to move from the current real-time operating speed Vi to the target speed V or target torque T corresponding to the regained new starting control signal; when the real-time operating speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing.

[0039] When the real-time running speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing. The motor continues to rotate with inertia and constantly detects the control signal sent by the external device. If the microprocessor MCU regains a new start control signal at this time, the microprocessor MCU will turn on all the lower bridge switches of the inverter, and the motor will enter the energy consumption braking mode for a duration of t1. Then the microprocessor MCU will energize the coil windings of each phase of the motor in a specific sequence to lock the rotor position for a duration of t2. Then it will regain a new start control signal and enter the sensorless starting and running motor state.

[0040] The above-mentioned motor is a three-phase permanent magnet synchronous motor, including coil windings U, V, and W. When the microprocessor MCU is blocking the PWM pulse processing, if the microprocessor MCU regains a new start control signal at this time, the microprocessor MCU turns on the three lower bridge switches Q4, Q5, and Q6 of the inverter, and the motor enters the energy consumption braking mode with a duration of t1 (for example, 1 second). Then, the microprocessor MCU will energize the three-phase coil windings U, V, and W of the motor in a specific order to lock the rotor position, with a duration of t2 (for example, 2 seconds).

[0041] When the motor receives a stop control signal from an external device, the microprocessor MCU controls the motor to decelerate. During the deceleration process, a timing time t3 (for example, 3 seconds) is set at the same time. The microprocessor MCU starts timing from the receipt of the stop control signal. When the duration of the stop control signal is greater than or equal to the timing time t3, the microprocessor MCU forcibly blocks the PWM pulse signal.

[0042] The above-mentioned set rotation speed Vref is a value in the range of 200 rpm to 400 rpm; specifically, the set rotation speed Vref is 300 rpm.

[0043] Through the above scheme, when all gear signals are removed (that is, when all switches K1, K2...Kn are disconnected, all gear input signals Tap1, Tap2...Tapn are equivalent to being disconnected from the microprocessor MCU), this scheme continues to output pulses to the inverter for controllable speed reduction processing. When the real-time operating speed Vi of the motor is less than the set speed Vref (for example, when Vref = 300 rpm), the microprocessor MCU performs pulse blocking processing to stop the motor at low speed, respond quickly to adapt to large inertia loads, and provide high user experience. Although the load inertia is large, at speeds of 300 rpm and below, the pre-positioned torque is completely The load can be stopped without causing abnormalities such as jitter and noise. The startup process at this time is the same as the normal startup process in a stationary state, ensuring a smooth startup. During the microprocessor MCU's pulse blocking process, even if a new gear position signal is received (i.e., when one of the switches K1, K2, ... Kn is closed, one of the gear input signals Tap1, Tap2, ... Tapn is input to the microprocessor MCU, which is equivalent to the microprocessor MCU re-receiving a new start control signal), no processing is performed until the motor completely stops. Only then is the motor restarted according to the new gear position signal using the pre-positioned start method. However, if the motor's real-time operating speed Vi is greater than or equal to the set speed Vref during the deceleration process and the microprocessor MCU re-receives the gear position signal, the motor is controlled to move from the real-time operating speed Vi to the speed V corresponding to the re-received gear position signal. This eliminates the need for direct pre-positioned startup at high speed according to traditional motor gear switching methods. This avoids abnormalities such as jitter, jerking, and noise, reduces current surges, effectively protects switching components, and extends the service life of the permanent magnet synchronous motor. In large inertia load applications, the permanent magnet synchronous motor can respond quickly and start again smoothly in situations such as gear signal recovery, frequent start and stop, and gear switching, avoiding abnormal conditions such as jitter, setbacks, and noise, and reducing current shocks. It can effectively protect switching devices, extend the service life of the permanent magnet synchronous motor, and greatly improve user experience.

[0044] The motor's movement from the real-time operating speed Vi to the speed V corresponding to the recovered gear signal refers to accelerating or decelerating the real-time operating speed Vi toward the speed V at a predetermined step size V0. Specifically, when the motor's real-time operating speed Vi is greater than the speed V corresponding to the recovered gear signal, the real-time operating speed Vi decelerates toward the speed V at a predetermined step size V0. When the motor's real-time operating speed Vi is less than the speed V corresponding to the recovered gear signal, the real-time operating speed Vi accelerates toward the speed V at a predetermined step size V0. The five gear input signals in Table 1 can be understood as new start-up control signals.

[0045] For example, see Table 1 for the motor's gear input signal and corresponding speed:

[0046]

[0047]

[0048] Table 1

[0049] For example, assuming the motor has 5 gears, namely Tap1, Tap2, Tap3, Tap4 and Tap5, and the speeds corresponding to the 5 gears are as shown in Table 1, then the motor's microprocessor MCU is connected to the 5 gear detection circuits, such as Figure 4 As shown in the figure, the motor's microprocessor MCU continuously checks whether the five gear detection circuits have gear input signals. When the motor is running in gear 3, the motor speed corresponding to the gear input signal Tap3 is 900 rpm. After the gear input signal Tap3 is removed, the motor speed is reduced from 900 rpm to 300 rpm. If the microprocessor MCU does not regain the corresponding gear signal during the speed reduction process, the motor speed will drop to 300 rpm. The microprocessor MCU then performs pulse blocking processing, causing the motor to stop directly. If the gear signal is regained during the pulse blocking process, although the load inertia is large, the pre-positioned torque can completely stop the load at speeds of 300 rpm and below, without any abnormalities such as jitter or noise. At this time, the startup process is the same as the normal startup from a standstill, ensuring a smooth startup.

[0050] If the microprocessor MCU regains the corresponding 1st gear input signal Tap1 after the motor stops, the motor will be started according to the pre-position start mode and the motor will restart, and the speed of the motor will rise to 600 rpm and then run stably;

[0051] When the motor is running in the 3rd gear, the motor speed corresponding to the 3rd gear input signal Tap3 is 900 rpm. After the 3rd gear input signal Tap3 is removed, the motor speed is reduced from 900 rpm to 300 rpm. Assume that when the motor speed drops to 800 rpm, the 1st gear input signal Tap1 is restored. Since the motor speed corresponding to the 1st gear input signal Tap1 is 600 rpm, which is lower than the current motor speed of 800 rpm, the motor continues to reduce speed until the speed drops to 600 rpm, so that the motor runs stably at 600 rpm.

[0052] When the motor is running in the 3rd gear, the motor operating speed corresponding to the 3rd gear input signal Tap3 is 900 rpm. After the 3rd gear input signal Tap3 is removed, the motor operating speed is reduced from 900 rpm to 300 rpm. Assume that when the motor operating speed drops to 800 rpm, the 5th gear input signal Tap5 is restored. Since the motor operating speed corresponding to the 5th gear input signal Tap5 is 1150 rpm, which is higher than the current motor operating speed of 800 rpm, the motor accelerates until the operating speed rises to 1150 rpm, so that the motor runs stably at a speed of 1150 rpm.

[0053] Through the above scheme, when the permanent magnet synchronous motor is in the deceleration stage, if the gear signal of the permanent magnet synchronous motor is restored, the microprocessor MCU adjusts the speed of the motor according to the regained gear signal, so that the permanent magnet synchronous motor can respond quickly and start smoothly again in situations such as gear signal recovery, frequent start and stop, and gear switching, avoiding abnormal conditions such as jitter, setbacks, and noise, and reducing current shock, which can effectively protect switching devices, extend the service life of the permanent magnet synchronous motor, and greatly improve user experience.

[0054] The certain step size V0 is determined based on the motor's rotational inertia and the difference between the real-time running speed Vi and the speed V corresponding to the regained gear signal. Specifically, the step size V0 is determined based on the motor's rotational inertia and the difference between the real-time running speed Vi and the speed V corresponding to the regained gear signal. Among them, K is a coefficient, which can be obtained through experiments, Vi is the real-time operating speed, V is the speed corresponding to the gear signal, and G is the motor rotational inertia. The coefficient K can be obtained through experimental means, and the value of the step size V0 is determined according to the motor rotational inertia and the actual value of the real-time operating speed Vi and the speed V corresponding to the regained gear signal, so that the step size V0 can be automatically adjusted to a reasonable value, so that the permanent magnet synchronous motor can better match the appropriate step size V0 for acceleration or deceleration, so that the permanent magnet synchronous motor can respond quickly and start smoothly again when the gear signal is restored, frequent start and stop, gear switching, etc., and can effectively improve the success rate of the permanent magnet synchronous motor restarting.

[0055] Assuming that the step size V0 in this embodiment is 10 rpm, the motor increases or decreases the speed by 10 rpm based on the real-time running speed Vi, so that the real-time running speed Vi is accelerated or decelerated to approach the speed V.

[0056] When all gear signals are removed, the microprocessor MCU continues to output pulses to the inverter for controllable speed reduction, that is, the speed reduction step V10 is set according to the difference between the current real-time running speed Vi of the motor and the set speed Vref, V10 = (Vi-Vref) / T, where T is the set time.

[0057] The speed reduction process refers to decelerating the motor toward the set speed Vref at a certain step distance V0 based on the real-time running speed Vi, until the real-time running speed Vi of the motor is less than the set speed Vref, at which time the microprocessor MCU performs pulse blocking processing. In this embodiment, the set speed Vref is obtained by experimental means, and the real-time running speed Vi is measured by a speed observer.

[0058] Example 2:

[0059] This embodiment is an improvement on the first embodiment. The improvement is that a VSP speed control circuit is used to replace the multi-way gear detection circuit and multiple switches. Figure 12 and Figure 13 As shown, the external device outputs a VSP signal to the permanent magnet synchronous motor with sensorless vector control. The VSP signal output by the external device is in the range of 0-10VDC, and its signal type is shown in Table 2. When the VSP signal is equal to 0V, it is regarded as a shutdown control signal. When the motor is running, it receives a shutdown control signal from the external device. The microprocessor MCU does not directly block the PWM pulse processing of the inverter, but continues to output pulses to the inverter for speed reduction processing and constantly detects the control signal sent by the external device. During the speed reduction processing, when the real-time running speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new start control signal, the motor is controlled to move from the current real-time running speed Vi to the target speed V or target torque T corresponding to the regained new start control signal; when the real-time running speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing. There are many new start control signals, 0.5V-2V is a start control signal; 2V-4V is a start control signal; 4V-6V is a start control signal; 6V-8V is a start control signal; 8V-10V is a start control signal;

[0060]

[0061]

[0062] Table 2

[0063] Similarly, a VSP speed control circuit can also be used to select the torque of the motor operation, as shown in Table 3. For example, when the VSP signal is equal to 0V, it is regarded as a shutdown control signal. During the operation of the motor, when it receives a shutdown control signal from an external device, the microprocessor MCU does not directly block the PWM pulse processing of the inverter, but continues to output pulses to the inverter for speed reduction processing, and constantly detects the control signal sent by the external device. During the speed reduction processing, when the real-time running speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new start control signal, the motor is controlled to move from the current real-time running speed Vi to the target torque T corresponding to the regained new start control signal; when the real-time running speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing. There are multiple new starting control signals. 0.5V-2V is a starting control signal corresponding to 20 N / m of torque; 2V-4V is also a starting control signal, corresponding to 40 N / m of torque; 4V-6V is also a starting control signal, corresponding to 60 N / m of torque; 6V-8V is also a starting control signal, corresponding to 80 N / m of torque; 8V-10V is also a starting control signal, corresponding to 100 N / m of torque.

[0064] When the VSP signal is a starting control signal of 2V-4V, the motor is controlled to run at a torque of 40 N / m. During the operation of the motor, when the VSP signal is equal to 0V, it is deemed to have received a shutdown control signal. The microprocessor MCU does not directly block the PWM pulse processing of the inverter, but continues to output pulses to the inverter for speed reduction processing. During the speed reduction process, when the real-time running speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new starting control signal (for example, the new starting control signal VSP is a starting control signal of 4V-6V, the motor is controlled from the current real-time running speed Vi to the control motor to run at a torque of 60 N / m. Other controls are not described in detail here.

[0065]

[0066]

[0067] Table 3

[0068] Furthermore, when an external device controls a sensorless vector-controlled permanent magnet synchronous motor using a PWM signal, the principle is similar to that of a VSP speed regulation signal, as shown in Table 4 and not described in detail here.

[0069] PWM signal Torque (N / m) Signal Type 0V 0 Shutdown control signal 10 pulses 20 Start control signal 20 pulses 40 Start control signal 30 pulses 60 Start control signal 40 pulses 80 Start control signal 50 pulses 100 Start control signal

[0070] Table 4

[0071] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited thereto. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention are equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A control method for a permanent magnet synchronous motor based on sensorless vector control, characterized in that When the motor is running and receives a shutdown control signal from an external device, the microprocessor MCU does not directly block the PWM pulse processing of the inverter, but continues to output pulses to the inverter for speed reduction processing and constantly detects the control signal sent by the external device. During the speed reduction process, when the real-time running speed Vi of the motor is greater than or equal to the set speed Vref and the microprocessor MCU regains a new start control signal, it controls the motor from the current real-time running speed Vi to the target speed V or target torque T corresponding to the regained new start control signal; When the real-time running speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing; When the real-time running speed Vi of the motor is less than the set speed Vref, the microprocessor MCU blocks the PWM pulse processing. The motor continues to rotate with inertia and constantly detects the control signal sent by the external device. If the microprocessor MCU regains a new start control signal at this time, the microprocessor MCU will turn on all the lower bridge switches of the inverter, and the motor will enter the energy consumption braking mode for a duration of t1. Then the microprocessor MCU will energize the coil windings of each phase of the motor in a specific sequence to lock the rotor position for a duration of t2. Then it will regain a new start control signal to control the motor to enter the sensorless starting state again.

2. The method for controlling the operation of a permanent magnet synchronous motor based on sensorless vector control according to claim 1, characterized in that: The motor is a three-phase permanent magnet synchronous motor, including coil windings U, V, and W. When the microprocessor MCU blocks the PWM pulse processing, if the microprocessor MCU regains a new start control signal at this time, the microprocessor MCU turns on the three lower bridge switches Q4, Q5, and Q6 of the inverter, and the motor enters the dynamic braking mode for a duration of t1. Then, the microprocessor MCU will energize the three-phase coil windings U, V, and W of the motor in a specific sequence to lock the rotor position for a duration of t2.

3. The method for controlling the operation of a permanent magnet synchronous motor based on sensorless vector control according to claim 1, characterized in that: When the motor receives a stop control signal from an external device, the microprocessor MCU will control the motor to decelerate. During the deceleration process, a timing time t3 is set at the same time. The microprocessor MCU starts timing from the receipt of the stop control signal. When the duration of the stop control signal is greater than or equal to the timing time t3, the microprocessor MCU forcibly blocks the PWM pulse signal.

4. The control method for the operation of a permanent magnet synchronous motor based on sensorless vector control according to claim 1, 2 or 3, characterized in that : Set the speed Vref to a value in the range of 200 rpm to 400 rpm.

5. The control method for the operation of a permanent magnet synchronous motor based on sensorless vector control according to claim 1, 2 or 3, characterized in that The motor moves from the real-time running speed Vi to the speed V corresponding to the regained gear signal, which means accelerating or decelerating at a certain step distance V0 on the basis of the real-time running speed Vi to move closer to the speed V.

6. The control method for the operation of a permanent magnet synchronous motor based on sensorless vector control according to claim 5 is characterized in that A certain step size V0 is determined based on the motor's rotational inertia and the difference between the real-time running speed Vi and the speed V corresponding to the regained gear signal.

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