Motor starting control method and device, medium, controller and program product

Abstract

The invention provides a motor starting control method and device, a medium, a controller and a program product, and the method comprises the steps: controlling a current vector applied to a q axis of a motor to be reduced according to an angle difference between a given coordinate system and an actual coordinate system in a state switching stage of motor starting; and when the angle difference between the given coordinate system and the actual coordinate system is smaller than a set value, switching from speed open-loop control to closed-loop control. According to the scheme provided by the invention, the situation of motor starting failure caused by current abrupt change and rotating speed abrupt change easily occurring in the motor starting switching process can be improved.

Description

Technical Field

[0001] The present invention relates to the field of control, and in particular to a motor startup control method, device, medium, controller and program product. A motor startup control method, device, computer-readable storage medium, controller and computer program product are specifically designed. Background Art

[0002] Permanent magnet synchronous motor (PMSM) has the advantages of high power density, good control performance, high power factor, and fast dynamic response. It is widely used in household appliances, industrial servos, electric vehicles and other fields. In the PMSM control system, the entire control process is a fusion of multiple algorithms, among which starting is the first step of control, especially the key link of low-speed and zero-speed starting. In order to achieve a smooth and impact-free starting process, accurate rotor position and speed information is required. This information can be obtained through position sensor control and position sensorless control. In view of cost considerations and the application scenario that does not require high sampling accuracy, most of them use position sensorless control. However, position sensorless control cannot accurately obtain the rotor position angle and speed when the motor is stationary, and the rotor needs to be forced to drag. During this process, the position sensorless estimator is also enabled. When the speed reaches a certain level, the observer can accurately observe the rotor position and speed information, and then switch from I / F control to position observerless control. However, there is an angle deviation between the actual position angle of the motor rotor and the I / F given position angle. If it is switched directly, the given q-axis current and the q-axis feedback current will not match during the switching process, causing motor speed oscillation and current mutation, which will lead to motor start-up failure. Summary of the invention

[0003] The main purpose of the present invention is to overcome the defects of the above-mentioned related technologies and provide a motor starting control method, device, medium, controller and program product to solve the problem of motor starting failure caused by sudden current and speed changes during motor starting switching in the related technologies.

[0004] On the one hand, the present invention provides a motor starting control method, comprising: in the state switching stage of the motor starting, controlling the current vector applied to the q-axis of the motor to decrease according to the angle difference between the given coordinate system and the actual coordinate system; when the angle difference between the given coordinate system and the actual coordinate system is less than a set value, switching from speed open-loop control to closed-loop control.

[0005] Optionally, controlling the current vector applied to the q-axis of the motor to decrease according to the angle difference between the given coordinate system and the actual coordinate system comprises: controlling the current vector applied to the q-axis of the motor according to the following formula:

[0006]

[0007] in, represents the current vector applied to the q axis of the motor, K represents the current reduction coefficient, K≤0, t 0 Indicates the time when the speed open-loop control starts to switch to the speed closed-loop control, t 1 Indicates the moment when the switch from speed open-loop control to speed closed-loop control is completed.

[0008] Optionally, the current reduction coefficient is determined according to the rotational speed of the motor and a maximum rotational speed and a minimum rotational speed allowed to switch from speed open-loop control to speed closed-loop control.

[0009] Optionally, the current reduction coefficient is determined according to the following formula based on the speed of the motor and the maximum speed and minimum speed allowed to switch from speed open-loop control to speed closed-loop control:

[0010]

[0011] Among them, ω s Indicates the speed of the motor during I / F startup, ω max and ω min They are the maximum speed and minimum speed that are allowed to switch from speed open-loop control to speed closed-loop control when there is no position sensor.

[0012] On the other hand, the present invention provides a motor starting control device, comprising: a control unit, used to control the reduction of the current vector applied to the q-axis of the motor according to the angle difference between the given coordinate system and the actual coordinate system during the state switching stage of the motor starting; a switching unit, used to switch from speed open-loop control to closed-loop control when the angle difference between the given coordinate system and the actual coordinate system is less than a set value.

[0013] Optionally, the control unit controls the current vector applied to the q-axis of the motor to decrease according to the angle difference between the given coordinate system and the actual coordinate system, including: controlling the current vector applied to the q-axis of the motor according to the following formula:

[0014]

[0015] in, represents the current vector applied to the q axis of the motor, K represents the current reduction coefficient, K≤0, t 0 Indicates the time when the speed open-loop control starts to switch to the speed closed-loop control, t 1 Indicates the moment when the switch from speed open-loop control to speed closed-loop control is completed.

[0016] Optionally, the current reduction coefficient is determined according to the rotational speed of the motor and a maximum rotational speed and a minimum rotational speed allowed to switch from speed open-loop control to speed closed-loop control.

[0017] Optionally, the current reduction coefficient is determined according to the following formula based on the speed of the motor and the maximum speed and minimum speed allowed to switch from speed open-loop control to speed closed-loop control:

[0018]

[0019] Among them, ω s Indicates the speed of the motor during I / F startup, ω max and ω min They are the maximum speed and minimum speed that are allowed to switch from speed open-loop control to speed closed-loop control when there is no position sensor.

[0020] Another aspect of the present invention provides a storage medium having a computer program stored thereon, wherein the program implements the steps of any of the aforementioned methods when executed by a processor.

[0021] In another aspect, the present invention provides a controller for a motor, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned methods when executing the program.

[0022] In another aspect, the present invention provides a controller for a motor, comprising any of the above-mentioned devices.

[0023] In yet another aspect, the present invention provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of any of the aforementioned methods are implemented.

[0024] According to the technical solution of the present invention, by controlling the trajectory of the given current vector reduction when the state is switched, the difference between the two coordinates is reduced to achieve smooth switching, thereby improving the current mutation and speed mutation that are prone to occur during the motor start-up switching process and ultimately lead to the failure of the motor start-up. Through the current drop fusion process of the present invention, there will be no current mutation during the switching process, the current drops smoothly, and the speed will not fluctuate greatly. The design of the current drop coefficient is related to the speed range allowed for switching, so that the switching accuracy is higher and there will be no fluctuations during switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0026] Figure 11 is a method schematic diagram of an embodiment of a motor startup control method provided by the present invention;

[0027] Figure 2a A schematic diagram of a rotor before starting according to an embodiment of the present invention is shown;

[0028] Figure 2b A schematic diagram of rotor positioning according to an embodiment of the present invention is shown;

[0029] Figure 3a The coordinate and current diagram of the initial stage of the I / F startup process is shown;

[0030] Figure 3b The coordinate and current diagram of the acceleration phase during the I / F startup process is shown;

[0031] Figure 3c The coordinate and current diagram of the switching process during I / F startup are shown;

[0032] Figure 3d The coordinates and current diagram of the switching completion during the I / F startup process are shown;

[0033] Figure 4a It shows the current variation trend during the process of speed open loop switching to speed closed loop;

[0034] Figure 4b It shows the speed change trend during the process of speed open loop switching to speed closed loop;

[0035] Figure 5 It is a method schematic diagram of a specific embodiment of the motor startup control method provided by the present invention;

[0036] Figure 6 It is a structural block diagram of an embodiment of the motor starting control device provided by the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] The present invention provides a motor starting control method. The control method is mainly used for permanent magnet synchronous motors. The motor is started by I / F starting, that is, it is started by I / F (current-frequency ratio control) control. The starting stage of the motor may specifically include: rotor positioning stage, open-loop acceleration stage and state switching stage. Due to its current closed-loop control, the current is controllable during starting, and overcurrent will not occur, thereby improving the reliability of control. I / F starting adopts current closed-loop speed open-loop control, and the speed and rotor position information used in the closed-loop control can be obtained by position-free sensor.

[0040] Figure 1 It is a method schematic diagram of an embodiment of a motor startup control method provided by the present invention.

[0041] like Figure 1 As shown, according to one embodiment of the present invention, the motor startup control method at least includes step S110 and step S120.

[0042] Step S110 , during the state switching stage of the motor starting, the current vector applied to the q-axis of the motor is controlled to decrease according to the angle difference between the given coordinate system and the actual coordinate system.

[0043] In the rotor positioning stage, in order to avoid positioning in the blind area, two positionings are performed, applying d-axis current id in the 0° and 90° directions respectively to position the rotor in a fixed position. Figure 2a A schematic diagram of a rotor before starting according to an embodiment of the present invention is shown. Figure 2b FIG. 2 shows a schematic diagram of rotor positioning according to an embodiment of the present invention. Figure 2a As shown in the figure, the rotor is in a random direction before starting. The rotor positioning before starting is to ensure that the rotor is in a certain position angle, because accurate rotor position angle is required in vector control, such as Figure 2b As shown, the rotor is positioned at phase A, and the rotor is positioned on the stator flux to ensure that the rotor position angle is a certain "0" degree before IF strong drag, and the given rotor position angle starts from "0" degree.

[0044] After the rotor positioning is completed, it enters the open-loop acceleration stage, and the iq* current is applied to the q axis for forced starting. According to the motor characteristics and the load size before starting, the current iq* is given, and the rotor position angle θ is given. The maximum current applied to the q axis does not exceed a preset percentage of the rated current of the motor (the preset percentage is greater than 100%, for example, 120%). The iq* current can be given by a ramp, and the rotor position angle can be given according to θ=∫ωdt. When the given current iq* climbs to the target current according to the ramp, under the condition that the load does not change suddenly, the motor realizes the dynamic balance between the motor output torque and the load torque according to its own "torque-power angle self-balancing" characteristics under this current. The relationship between the actual motor coordinate system and the I / F given coordinate system during the starting process is as follows: Figure 3a , Figure 3b , Figure 3c and Figure 3d shown.

[0045] Figure 3a The coordinate and current diagram of the initial stage of the I / F startup process is shown. Figure 3b The coordinate and current diagram of the acceleration phase during the I / F startup process is shown. Figure 3c The coordinate and current diagram of the switching process during I / F startup are shown. Figure 3d The coordinates and current diagram of the switching completion during the I / F startup process are shown.

[0046] like Figure 3a As shown, in the initial stage, the given coordinate system (d*-q* coordinate system) is initially set to lag behind the actual coordinate system (dq coordinate system) by 90°, at which time the d axis coincides with the q* axis; Figure 3b As shown, during the acceleration phase, the given current vector Starting from the d-axis, the motor slowly accelerates its rotation as the given position angle changes. This will cause a phase difference Δθ between the given d*-q* coordinate system and the motor's real dq coordinate system. Wr is the speed of the rotor's actual coordinate system dq, and We* is the speed of the given coordinate system d*-q*. The phase difference will cause the current vector in the d*-q* coordinate system to generate a current component in the dq coordinate system, thereby generating an electromagnetic torque. When the electromagnetic torque is greater than the load torque, the motor starts to rotate. The torque expression is:

[0047]

[0048] It can be seen from formula (1) that when the angle difference Δθ between the two coordinates is equal to 0, the electromagnetic torque generated is the largest. At this time, the given coordinate system and the actual coordinate system completely coincide, thus realizing dual closed-loop FOC control.

[0049] The state switching stage is specifically when the speed of the motor increases to the set speed, switching from I / F control to position observer-free control. In the open-loop acceleration stage, in order to overcome the motor's own torque such as motor groove, friction and load torque, current is applied to the q-axis to generate electromagnetic torque; state switching means that when the speed increases to a certain stage, the position observer-free can accurately observe the rotor position and speed information, and at this time, the I / F control is switched to position observer-free control. The current loop always remains in a closed-loop state during the I / F startup process, which can effectively avoid excessive current damage to the motor caused by sudden load changes.

[0050] When the load does not change suddenly and the open loop accelerates to the set speed and current, the motor maintains a fixed angle difference Δθ between the given d*-q* coordinate system and the motor's real dq coordinate system based on its own "torque-power angle balance" characteristics. From formula (1), it can be seen that the electromagnetic torque is directly related to the given current vector and the angle difference between the two coordinate systems. When the given current vector decreases and the electromagnetic torque remains unchanged, the angle difference between the two coordinate systems will decrease. When the angle difference decreases to the range where the closed loop can be switched, the control mode is switched from speed open loop to closed loop to complete dual closed loop control.

[0051] Therefore, the current vector applied to the q-axis of the motor is reduced according to the angle difference between the given coordinate system and the actual coordinate system to reduce the angle difference Δθ between the two coordinates and achieve smooth switching. In a specific embodiment, the current vector applied to the q-axis of the motor is controlled according to the following formula (2):

[0052]

[0053] in, represents the current vector applied to the q axis of the motor, K represents the current reduction coefficient, K≤0, t 0 Indicates the time when the speed open-loop control starts to switch to the speed closed-loop control, t 1 Indicates the moment when the switch from speed open-loop control to speed closed-loop control is completed.

[0054] From equation (1), we can see that the actual electromagnetic torque and the given current vector in the given coordinate system are It is directly related to the angle difference between the two coordinate systems. To ensure that the electromagnetic torque remains unchanged, the current vector In order to ensure that the required electromagnetic torque remains unchanged, the angle difference between the two coordinate systems will decrease. It is assumed that at t 0 At time t, the speed is switched to closed loop. 1 The switching is completed at the moment, and the current vector change during this process can be expressed as formula (2).

[0055] Among them, the current drop coefficient k iThat is, the change process of the current vector, the current drop coefficient can be a constant. In a preferred embodiment, the current drop coefficient is determined according to the speed of the motor and the maximum speed and minimum speed that allow switching from speed open-loop control to speed closed-loop control. In a specific implementation, the current drop coefficient is determined according to the magnitude relationship between the motor speed and the maximum speed, the minimum speed, and the average of the maximum speed and the minimum speed. For example, the change law of the current drop coefficient K can be expressed as:

[0056]

[0057] Current drop factor k i According to the maximum speed and minimum speed setting allowed for closed loop switching, ω s Indicates the motor speed during I / F startup, ω max and ω min They are the maximum speed and minimum speed that are allowed to switch from speed open-loop control to speed closed-loop control when there is no position sensor.

[0058] Step S120: When the angle difference between the given coordinate system and the actual coordinate system is less than a set value, the speed open-loop control is switched to the closed-loop control.

[0059] Specifically, the current vector applied to the q-axis of the motor is reduced according to the angle difference control between the given coordinate system and the actual coordinate system, and the angle difference between the two coordinates gradually decreases as the current gradually decreases, and finally switches to dual closed-loop vector control.

[0060] like Figure 3c , Figure 3d As shown, during the switching process, when the given current vector When the angle difference Δθ decreases, the angle difference Δθ between the two coordinate systems will decrease. When the angle difference Δθ decreases to the range where the closed loop can be switched (less than the set value), the control mode switches from speed open loop to closed loop. When the switching is completed, the angle difference Δθ between the given coordinate system and the actual coordinate system is equal to 0. At this time, the given coordinate system and the actual coordinate system completely coincide, thereby realizing dual closed-loop FOC control.

[0061] Figure 4a The current change trend during the speed open loop switching speed closed loop is shown. Figure 4b The figure shows the speed change trend during the speed open-loop switching speed closed-loop process. Through the current drop fusion process of the present invention, there will be no current mutation during the switching process, the current drops smoothly, and the speed does not fluctuate greatly. Figure 4a As shown, the horizontal axis represents time t, unit: s (seconds), the vertical axis represents the current iq* applied to the q axis, unit: A (ampere), the t0 period is the current drop process, the t1 period is the closed loop switching process, and the t2 period is the closed loop operation process; Figure 4b As shown in the figure, the horizontal axis represents time t, unit: s (seconds), the vertical axis represents the motor speed We, unit: r / min (revolutions / minute), the t0 period is the positioning stage, the t1 period is the IF forced drag process, the t3 period is the closed loop switching process, and the t4 period is the closed loop operation. Figure 4a and Figure 4b It expresses different meanings.

[0062] In this process, the angle difference Δθ between the two coordinates also decreases, and decreases to the designed switching threshold, completing the state switching and double closed-loop operation control. s ) is related to the speed difference allowed for switching, which allows for higher switching accuracy and eliminates fluctuations during switching.

[0063] In order to clearly illustrate the technical solution of the present invention, the execution process of the motor startup control method provided by the present invention is described below with reference to a specific embodiment.

[0064] Figure 5 FIG. 1 is a schematic diagram of a specific embodiment of the motor startup control method provided by the present invention. Figure 5 As shown, the rotor is positioned before starting, and the q-axis current is applied during starting to perform current closed-loop control. When the speed reaches the set speed and the q-axis current reaches the set current, the q-axis current is reduced to determine whether the angle difference between the given coordinate system and the real coordinate system is less than the set value. When it is determined that the angle difference between the given coordinate system and the real coordinate system is less than the set value, the speed open-loop control is switched to the speed closed-loop control, and the start-up is successful.

[0065] The present invention also provides a motor starting control device. The control device is mainly used for permanent magnet synchronous motors. The motor is started by I / F starting, that is, it is started by I / F (current-frequency ratio control) control method. The starting stage of the motor can specifically include: rotor positioning stage, open-loop acceleration stage and state switching stage. Due to its current closed-loop control, the current is controllable during starting, and overcurrent will not occur, thereby improving the reliability of control. I / F starting adopts current closed-loop speed open-loop control, and the speed and rotor position information used in the closed-loop control can be obtained by position-free sensor.

[0066] Figure 6 FIG. 1 is a structural block diagram of an embodiment of a motor start control device provided by the present invention. Figure 6 As shown, the motor startup control device 100 includes: a control unit 110 and a switching unit 120 .

[0067] The control unit 110 is used to control the current vector applied to the q-axis of the motor to decrease according to the angle difference between the given coordinate system and the actual coordinate system during the state switching stage of the motor starting.

[0068] In the rotor positioning stage, in order to avoid positioning in the blind area, two positionings are performed, applying d-axis current id in the 0° and 90° directions respectively to position the rotor in a fixed position. Figure 2a A schematic diagram of a rotor before starting according to an embodiment of the present invention is shown. Figure 2b FIG. 2 shows a schematic diagram of rotor positioning according to an embodiment of the present invention. Figure 2a As shown in the figure, the rotor is in a random direction before starting. The rotor positioning before starting is to ensure that the rotor is in a certain position angle, because accurate rotor position angle is required in vector control, such as Figure 2b As shown, the rotor is positioned at phase A, and the rotor is positioned on the stator flux to ensure that the rotor position angle is a certain "0" degree before IF strong drag, and the given rotor position angle starts from "0" degree.

[0069] After the rotor positioning is completed, it enters the open-loop acceleration stage, and the iq* current is applied to the q axis for forced starting. According to the motor characteristics and the load size before starting, the current iq* is given, and the rotor position angle θ is given. The maximum current applied to the q axis does not exceed a preset percentage of the rated current of the motor (the preset percentage is greater than 100%, for example, 120%). The iq* current can be given by a ramp, and the rotor position angle can be given according to θ=∫ωdt. When the given current iq* climbs to the target current according to the ramp, under the condition that the load does not change suddenly, the motor realizes the dynamic balance between the motor output torque and the load torque according to its own "torque-power angle self-balancing" characteristics under this current. The relationship between the actual motor coordinate system and the I / F given coordinate system during the starting process is as follows: Figure 3a , Figure 3b , Figure 3c and Figure 3d shown.

[0070] like Figure 3a As shown, in the initial stage, the given coordinate system (d*-q* coordinate system) is initially set to lag behind the actual coordinate system (dq coordinate system) by 90°, at which time the d axis coincides with the q* axis; Figure 3b As shown, during the acceleration phase, the given current vector Starting from the d-axis, the motor slowly accelerates its rotation as the given position angle changes. This will cause a phase difference Δθ between the given d*-q* coordinate system and the motor's real dq coordinate system. Wr is the speed of the rotor's actual coordinate system dq, and We* is the speed of the given coordinate system d*-q*. The phase difference will cause the current vector in the d*-q* coordinate system to generate a current component in the dq coordinate system, thereby generating an electromagnetic torque. When the electromagnetic torque is greater than the load torque, the motor starts to rotate. The torque expression is:

[0071]

[0072] It can be seen from formula (1) that when the angle difference Δθ between the two coordinates is equal to 0, the electromagnetic torque generated is the largest. At this time, the given coordinate system and the actual coordinate system completely coincide, thus realizing dual closed-loop FOC control.

[0073] The state switching stage is specifically when the speed of the motor increases to the set speed, switching from I / F control to position observer-free control. In the open-loop acceleration stage, in order to overcome the motor's own torque such as motor groove, friction and load torque, current is applied to the q-axis to generate electromagnetic torque; state switching means that when the speed increases to a certain stage, the position observer-free can accurately observe the rotor position and speed information, and at this time, the I / F control is switched to position observer-free control. The current loop always remains in a closed-loop state during the I / F startup process, which can effectively avoid excessive current damage to the motor caused by sudden load changes.

[0074] When the load does not change suddenly and the open loop accelerates to the set speed and current, the motor maintains a fixed angle difference Δθ between the given d*-q* coordinate system and the motor's real dq coordinate system based on its own "torque-power angle balance" characteristics. From formula (1), it can be seen that the electromagnetic torque is directly related to the given current vector and the angle difference between the two coordinate systems. When the given current vector decreases and the electromagnetic torque remains unchanged, the angle difference between the two coordinate systems will decrease. When the angle difference decreases to the range where the closed loop can be switched, the control mode is switched from speed open loop to closed loop to complete dual closed loop control.

[0075] Therefore, the current vector applied to the q-axis of the motor is reduced according to the angle difference between the given coordinate system and the actual coordinate system to reduce the angle difference Δθ between the two coordinates and achieve smooth switching. In a specific embodiment, the current vector applied to the q-axis of the motor is controlled according to the following formula (2):

[0076]

[0077] in, represents the current vector applied to the q axis of the motor, K represents the current reduction coefficient, K≤0, t 0 Indicates the time when the speed open-loop control starts to switch to the speed closed-loop control, t 1 Indicates the moment when the switch from speed open-loop control to speed closed-loop control is completed.

[0078] From equation (1), we can see that the actual electromagnetic torque and the given current vector in the given coordinate system are It is directly related to the angle difference between the two coordinate systems. To ensure that the electromagnetic torque remains unchanged, the current vector In order to ensure that the required electromagnetic torque remains unchanged, the angle difference between the two coordinate systems will decrease. It is assumed that at t 0 At time t, the speed is switched to closed loop. 1The switching is completed at the moment, and the current vector change during this process can be expressed as formula (2).

[0079] Among them, the current drop coefficient k i That is, the change process of the current vector, the current drop coefficient can be a constant. In a preferred embodiment, the current drop coefficient is determined according to the speed of the motor and the maximum speed and minimum speed that allow switching from speed open-loop control to speed closed-loop control. In a specific implementation, the current drop coefficient is determined according to the magnitude relationship between the motor speed and the maximum speed, the minimum speed, and the average of the maximum speed and the minimum speed. For example, the change law of the current drop coefficient K can be expressed as:

[0080]

[0081] Current drop factor k i According to the maximum speed and minimum speed setting allowed for closed loop switching, ω s Indicates the motor speed during I / F startup, ω max and ω min They are the maximum speed and minimum speed that are allowed to switch from speed open-loop control to speed closed-loop control when there is no position sensor.

[0082] The switching unit 120 is used to switch from speed open-loop control to closed-loop control when the angle difference between the given coordinate system and the actual coordinate system is less than a set value.

[0083] Specifically, the current vector applied to the q-axis of the motor is reduced according to the angle difference control between the given coordinate system and the actual coordinate system, and the angle difference between the two coordinates gradually decreases as the current gradually decreases, and finally switches to dual closed-loop vector control.

[0084] like Figure 3c , Figure 3d As shown, during the switching process, when the given current vector When the angle difference Δθ decreases, the angle difference Δθ between the two coordinate systems will decrease. When the angle difference Δθ decreases to the range where the closed loop can be switched (less than the set value), the control mode switches from speed open loop to closed loop. When the switching is completed, the angle difference Δθ between the given coordinate system and the actual coordinate system is equal to 0. At this time, the given coordinate system and the actual coordinate system completely coincide, thereby realizing dual closed-loop FOC control.

[0085] Figure 4a The current change trend during the speed open loop switching speed closed loop is shown. Figure 4b The figure shows the speed change trend during the speed open-loop switching speed closed-loop process. Through the current drop fusion process of the present invention, there will be no current mutation during the switching process, the current drops smoothly, and the speed does not fluctuate greatly. Figure 4aAs shown, the horizontal axis represents time t, unit: s (seconds), the vertical axis represents the current iq* applied to the q axis, unit: A (ampere), the t0 period is the current drop process, the t1 period is the closed loop switching process, and the t2 period is the closed loop operation process; Figure 4b As shown in the figure, the horizontal axis represents time t, unit: s (seconds), the vertical axis represents the motor speed We, unit: r / min (revolutions / minute), the t0 period is the positioning stage, the t1 period is the IF forced drag process, the t3 period is the closed loop switching process, and the t4 period is the closed loop operation. Figure 4a and Figure 4b It expresses different meanings.

[0086] In this process, the angle difference Δθ between the two coordinates also decreases, and decreases to the designed switching threshold, completing the state switching and double closed-loop operation control. s ) is related to the speed difference allowed for switching, which allows for higher switching accuracy and eliminates fluctuations during switching.

[0087] The present invention also provides a storage medium corresponding to the motor startup control method, on which a computer program is stored, and when the program is executed by a processor, the steps of any of the above methods are implemented.

[0088] The present invention also provides a motor controller corresponding to the motor startup control method, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned methods when executing the program.

[0089] The present invention also provides a motor controller corresponding to the motor starting control device, including any of the motor starting control devices described above.

[0090] The present invention also provides a computer program product corresponding to the motor startup control method, comprising a computer program, and when the computer program is executed by a processor, the steps of any of the aforementioned methods are implemented.

[0091] Accordingly, the solution provided by the present invention reduces the difference between the two coordinates by controlling the trajectory of the given current vector reduction when the state is switched, thereby achieving smooth switching and improving the situation in which the motor startup switching process is prone to current mutation and speed mutation, which ultimately leads to motor startup failure. Through the current drop fusion process of the present invention, there will be no current mutation during the switching process, the current drops smoothly, and there will be no large fluctuations in speed. The design of the current drop coefficient is related to the speed range allowed for switching, so that the switching accuracy is higher and there will be no fluctuations during switching.

[0092] The solution provided by the present invention optimizes state switching to allow the motor to smoothly complete the transition from speed open-loop control to speed closed-loop control, which can not only meet the rapidity of startup, but also effectively avoid current overshoot during the switching process that may cause motor startup failure.

[0093] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present invention and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0094] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0095] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0096] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the relevant technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0097] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A motor startup control method, characterized in that: include: In the state switching stage of the motor starting, the current vector applied to the q-axis of the motor is controlled to decrease according to the angle difference between the given coordinate system and the actual coordinate system; When the angle difference between the given coordinate system and the actual coordinate system is less than a set value, the speed open-loop control is switched to the closed-loop control.

2. The method according to claim 1, characterized in that Controlling the reduction of the current vector applied to the q-axis of the motor according to the angle difference between the given coordinate system and the actual coordinate system includes: The current vector applied to the q-axis of the motor is controlled according to the following formula: in, represents the current vector applied to the q-axis of the motor, K represents the current reduction coefficient, K≤0, t0 represents the moment when the speed open-loop control starts to switch to the speed closed-loop control, and t1 represents the moment when the speed open-loop control is switched to the speed closed-loop control.

3. The method according to claim 2, characterized in that The current reduction coefficient is determined according to the rotation speed of the motor and the maximum rotation speed and the minimum rotation speed allowed to switch from the speed open-loop control to the speed closed-loop control.

4. The method according to claim 3, characterized in that The current reduction coefficient is determined according to the motor speed and the maximum speed and minimum speed allowed to switch from speed open-loop control to speed closed-loop control according to the following formula: Among them, ω s Indicates the speed of the motor during I / F startup, ω max and ω min They are the maximum speed and minimum speed that are allowed to switch from speed open-loop control to speed closed-loop control when there is no position sensor.

5. A motor starting control device, characterized in that: include: A control unit, configured to control the current vector applied to the q-axis of the motor to decrease according to the angle difference between the given coordinate system and the actual coordinate system during the state switching stage of the motor starting; The switching unit is used to switch from speed open-loop control to closed-loop control when the angle difference between the given coordinate system and the actual coordinate system is less than a set value.

6. The device according to claim 5, characterized in that The control unit controls the current vector applied to the q-axis of the motor to decrease according to the angle difference between the given coordinate system and the actual coordinate system, including: The current vector applied to the q-axis of the motor is controlled according to the following formula: in, represents the current vector applied to the q-axis of the motor, K represents the current reduction coefficient, K≤0, t0 represents the moment when the speed open-loop control starts to switch to the speed closed-loop control, and t1 represents the moment when the speed open-loop control is switched to the speed closed-loop control.

7. The device according to claim 6, characterized in that The current reduction coefficient is determined according to the rotation speed of the motor and the maximum rotation speed and the minimum rotation speed allowed to switch from speed open-loop control to speed closed-loop control.

8. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps of any method described in claims 1-4 are implemented.

9. A controller for a motor, characterized in that: The invention comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the method described in any one of claims 1 to 4 are implemented, or the invention comprises a startup control device described in any one of claims 5 to 7.

10. A computer program product, characterized in that The invention comprises a computer program, which implements the steps of the method according to any one of claims 1 to 4 when being executed by a processor.

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