Method, device, controller and system for controlling synchronous motor of handheld electric tool

Abstract

The invention discloses a handheld electric tool synchronous motor control method, device, controller and system, and the method comprises the steps that the controller obtains the current operation parameters of a synchronous motor, and the operation parameters comprise a bus voltage value, a bus current value, a duty ratio and a commutation interval; the current input power is calculated according to the bus voltage value, the bus current value and the duty ratio, and the current rotating speed is calculated according to the commutation interval and the number of pole pairs of the synchronous motor; searching the current input power and the output torque corresponding to the rotating speed based on a set lookup table; based on the set output torque threshold value and the current output torque, the target operation state of the synchronous motor at the next moment is decided. According to the application, automatic shutdown can be performed in time when the set output torque value is reached, and the output torque value is smaller than the torque value when the output head is clamped and larger than the torque value when an operator normally uses a tool, so that the use requirement of the operator is met, and the operator is protected from being injured by the tool.

Description

Technical Field

[0001] The present application relates to the field of automatic control technology, and in particular to a method, device, controller and system for controlling a synchronous motor of a handheld electric tool. Background Art

[0002] Handheld power tools are increasingly used in various production fields and life scenarios, and the performance requirements for power tools are gradually increasing, such as the need for larger output torque to improve work efficiency. With the popularization of brushless motors, in order to meet the actual needs of operators, brushless synchronous motors are widely used in handheld power tools to improve the torque of handheld power tools.

[0003] Currently, for handheld power tools, during operation, as the torque increases, if the output head occasionally gets stuck, the operator needs to manually cut off the power supply in time to shut down the device.

[0004] However, due to excessive torque, the tool can easily get out of control, making it impossible for the operator to cut off the power supply in time, resulting in safety accidents. Summary of the invention

[0005] The purpose of this application is to provide a synchronous motor control method, device, controller and control system to achieve precise control of the operating state of the synchronous motor.

[0006] To achieve the above objectives, this application provides the following solutions: In a first aspect, the present application provides a method for controlling a synchronous motor of a handheld electric tool, the method being used for a controller in a handheld electric tool, the method comprising: The handheld electric tool controller obtains its current operating parameters, which include bus voltage value, bus current value, duty cycle and commutation interval; The current input power of the synchronous motor is calculated according to the bus voltage value, the bus current value and the duty cycle, and the current rotation speed is calculated according to the commutation interval and the number of pole pairs of the synchronous motor of the handheld electric tool; The controller searches for the output torque corresponding to the current input power and the speed based on a set lookup table, wherein the lookup table includes a correspondence between the input power and the speed of the synchronous motor and the output torque of the synchronous motor; Based on the set output torque threshold and the current output torque, the target operating state of the synchronous motor at the next moment is determined.

[0007] Optionally, in the handheld electric tool synchronous motor control method provided by the present application, the torque threshold includes a set shutdown output torque value and a limited output torque value, and the controller determines the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque, including: If the current output torque is greater than the set shutdown output torque value, determining the target operating state to be shutdown; Alternatively, if the current output torque is greater than the limited output torque value, the target operating state is determined to be to reduce the current output torque.

[0008] Optionally, the synchronous motor control method provided by the present application, when it is determined that the target operating state is shutdown, the method further includes: The controller generates a stop instruction and sends it to the motor drive module, so that the motor drive module responds to the stop instruction and controls the synchronous motor to stop running at the next moment.

[0009] Optionally, the handheld electric tool synchronous motor control method provided by the present application, when it is determined that the target operating state is to reduce the current output torque, the method further includes: The controller generates a control instruction and sends it to the motor drive module, so that the motor drive module responds to the control instruction, so that the synchronous motor reduces the duty cycle at the next moment and reduces the output torque.

[0010] Optionally, in the handheld electric tool synchronous motor control method provided in the present application, obtaining the current operating parameters of the synchronous motor includes: The controller obtains the current bus voltage value and the current state information of the start switch, wherein the state information indicates the current state of the controller; When the state information indicates that the controller is currently in an on state, determining whether an enable flag of the synchronous motor is set; When the enable flag is set, the current bus current value and the current duty cycle of the synchronous motor are obtained.

[0011] Optionally, the handheld electric tool synchronous motor control method provided by the present application, when the state information indicates that the synchronous motor is currently in an off state, the method further includes: The controller generates a shutdown control instruction to stop the synchronous motor and set the enable flag.

[0012] Optionally, the handheld electric tool synchronous motor control method provided by the present application, when the enable flag is not set, the method further includes: The controller returns to execute the step of acquiring the bus voltage value of the synchronous motor and the status information of the starting switch.

[0013] In a second aspect, the present application provides a synchronous motor control device for a handheld electric tool, the device comprising: An acquisition module is used to acquire its current operating parameters, wherein the operating parameters include bus voltage value, bus current value, duty cycle and commutation interval; A calculation module, used for calculating the current input power of the synchronous motor according to the bus voltage value, the bus current value and the duty cycle, and calculating the current speed according to the commutation interval and the number of pole pairs of the synchronous motor; A search module, used to search for the current input power and the output torque corresponding to the speed based on a set lookup table, wherein the lookup table includes a corresponding relationship between the input power of the controller, the motor speed and the output torque of the synchronous motor; The decision module is used to determine the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque.

[0014] In a third aspect, the present application provides a handheld power tool controller, the controller comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the handheld power tool synchronous motor control method as described in the first aspect.

[0015] In a fourth aspect, the present application provides a handheld electric tool synchronous motor control system, the control system comprising: A synchronous motor, a power supply and a controller assembly; the controller assembly includes a motor drive module, a voltage sampling module, a current sampling module and the controller described in the third aspect; The voltage sampling module is used to collect the bus voltage value of the control system, the current sampling module is used to collect the bus current value of the control system, and the motor driving module is used to drive the synchronous motor; The controller is used to execute the handheld power tool synchronous motor control method as described in the first aspect.

[0016] According to the specific embodiments provided in this application, this application discloses the following technical effects: The present application provides a control method, device, controller and control system for a synchronous motor of a handheld power tool. The controller of the handheld power tool collects its current operating parameters including bus voltage value, bus current value, duty cycle and commutation interval in real time, and then determines the current input power and speed of the controller by processing the acquired operating parameters. Then, the current output torque of the synchronous motor of the handheld power tool is searched by setting a lookup table including the correspondence between input power, speed and output torque. Finally, the determined output torque is compared with the set torque threshold to implement a limited output torque control strategy or a set torque value shutdown function.

[0017] That is, through the control method provided in the embodiment of the present application, the synchronous motor in the handheld power tool can automatically shut down when the set output torque value is reached. The output torque value is less than the torque value when the output head is stuck, and greater than the torque value when the operator uses the tool normally. This can meet the operator's usage needs and protect the operator from tool damage. Therefore, when an abnormal situation occurs in the handheld power tool, it can automatically shut down or reduce the output torque, avoiding the need for manual operation by the operator and avoiding safety hazards after the operator is separated. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a schematic diagram of the structure of a synchronous motor control system for a handheld power tool according to some embodiments of the present application; Figure 2 A schematic flow chart of a synchronous motor control method for a handheld power tool according to some embodiments of the present application; Figure 3 A schematic flow chart of a synchronous motor control method for a handheld power tool according to some other embodiments of the present application; Figure 4 A flowchart of a synchronous motor control method for a handheld power tool according to some further embodiments of the present application; Figure 5 A flowchart of a synchronous motor control method for a handheld electric tool according to some embodiments of the present application; Figure 6 This is a schematic structural diagram of a synchronous motor control device for a handheld electric tool according to some embodiments of the present application; Figure 7 A schematic diagram of the structure of a central processing unit provided for some embodiments of the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0022] It can be understood that for handheld power tools, in order to improve their operating safety and prevent accidents caused by separation from the operator due to the inability to automatically stop or reduce the output torque in the event of an accident, this application proposes a control method for the synchronous motor of a handheld power tool. This method is used for the synchronous motor control system in the handheld power tool.

[0023] like Figure 1 The figure shows a schematic diagram of the structure of a synchronous motor control system. The synchronous motor can be a motor device installed in an electric device, such as a motor of a handheld electric tool, such as a water drill, etc. The control system can specifically include a controller assembly, a power supply and a synchronous motor. The controller assembly is electrically connected to the power supply and the synchronous motor.

[0024] The controller assembly may include a central processing unit (ie, a controller), a voltage sampling module, a current sampling module, and a motor drive module.

[0025] The central processing unit in the controller assembly can be used to receive and process data from the voltage sampling module and the current sampling module, and then calculate the current input power of the controller based on the current motor operating status, the collected data of the current sampling module and the voltage sampling module. Finally, the current output torque of the synchronous motor can be obtained by looking up the configured lookup table based on the input power and speed, so as to achieve precise control of the output torque of the synchronous motor according to the current output torque and the set torque threshold.

[0026] That is, in the present application, for handheld power tools, in order to improve the safety of operation, a control method is provided, which can enable the synchronous motor in the handheld power tool to stop automatically and in time when the set output torque value is reached, or automatically reduce the output torque, so that the output torque value is less than the torque value when the output head is stuck, and greater than the torque value when the operator uses the tool normally, which can meet the operator's usage needs and protect the operator from tool damage.

[0027] In order to better understand the synchronous motor control method provided by the present application, it is described in detail below with reference to the accompanying drawings.

[0028] Figure 2 A schematic flow chart of a synchronous motor control method for a handheld power tool provided in some embodiments of the present application.

[0029] This method can be Figure 2 The controller shown in the figure is executed, and specifically can be executed by a central processing unit therein, and the method can specifically include the following steps: S110, the handheld electric tool controller obtains its current operating parameters, which include bus voltage value, bus current value, duty cycle and commutation interval.

[0030] S120, the controller calculates the current input power according to the current value, the voltage value and the duty cycle, and calculates the current rotation speed according to the commutation interval and the number of pole pairs of the synchronous motor.

[0031] S130, the controller searches for the output torque corresponding to the current input power and rotational speed based on a set lookup table, wherein the lookup table includes the correspondence between the input power and rotational speed of the controller and the output torque of the synchronous motor of the handheld power tool.

[0032] S140, the controller determines the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque.

[0033] Specifically, in an embodiment of the present application, during the operation of the synchronous motor of a handheld power tool, after the control system of the synchronous motor completes initialization and enters the working state, that is, during the operation of the synchronous motor, in order to be able to control the output torque of the synchronous motor of the handheld power tool in real time to avoid excessive output torque, which causes the synchronous motor to be out of the operator's control and causes a safety accident, the controller may perform the following steps.

[0034] Combination Figure 1 As shown, in order to ensure the safe operation of the synchronous motor, the controller can first obtain the current operating parameters, that is, the operating status data, through the configured sensors.

[0035] For example, the current bus voltage value of the synchronous motor can be obtained through the voltage sampling module, the current bus current value of the synchronous motor can be obtained through the current sampling module, and the current duty cycle can be obtained.

[0036] It is also possible to obtain the time interval t (unit: s) for the controller to control the synchronous motor drive module to perform electrical commutation for one electrical cycle, that is, the commutation interval.

[0037] Furthermore, the controller can calculate the current input power of the synchronous motor based on the current operating parameters, namely the bus voltage value, the bus current value and the duty cycle, that is, by calculating the product of the bus voltage value, the bus current value and the duty cycle to obtain the current input power of the controller.

[0038] Furthermore, the controller can calculate the current rotation speed according to the number of pole pairs of the synchronous motor at the current commutation interval.

[0039] It can be understood that for synchronous motors, the rotor speed is equal to the stator electrical commutation speed. The central processor is set to control the motor drive module to perform electrical commutation for an electrical cycle. The time interval t (unit s), the number of pole pairs of the synchronous motor is p (dimensionless), then the speed n (unit rpm) = 60 / (t*p), where 60 means one minute is 60 seconds.

[0040] Among them, 60 represents one minute, p is the number of pole pairs of the synchronous motor, and t is the electrical commutation period of the synchronous motor.

[0041] Furthermore, the current output torque of the synchronous motor can be determined based on the calculated input power and rotation speed and a set lookup table.

[0042] The lookup table may include a correspondence between the input power and rotation speed of the controller and the output torque of the synchronous motor.

[0043] That is, it can be understood that in the embodiment of the present application, in order to find the current output torque according to the determined input power and speed, and then realize the precise control of the output torque, a lookup table can be configured in the central processing unit, that is, a lookup table of the corresponding relationship between the input power, speed and output torque of the synchronous motor of the controller can be established. Then, after the current input power of the controller is calculated through the steps provided above, the lookup table can be used to obtain the current output torque of the synchronous motor in the control system by looking up the table.

[0044] Finally, the determined output torque may be compared with a set torque threshold, and the target operating state of the synchronous motor at the next moment may be determined based on the comparison result.

[0045] For example, when the current output torque obtained through the lookup table is not greater than the set torque threshold, it means that the current operating state meets the requirements and can be maintained; or, if the current output torque is greater than the set torque threshold, it means that the output torque is too large and does not meet the current operating environment, such as the output traction force is too large, or the operating state is dangerous, then a shutdown command can be directly generated to stop the synchronous motor directly, or a control command can be generated to reduce the output torque to ensure that the output torque is within a normal range.

[0046] It can be understood that in the embodiment of the present application, the operating parameters including bus voltage value, bus current value, duty cycle and commutation interval are collected in real time by the central processing unit in the controller assembly of the handheld power tool, and then the current input power and speed of the controller are determined by processing the acquired operating parameters, and then the output torque is found by setting a lookup table including the correspondence between input power, speed and output torque, and finally the determined output torque is compared with the set torque threshold to implement the output torque control strategy or the set torque value shutdown function.

[0047] That is, the synchronous motor control method for handheld power tools provided in the embodiment of the present application can automatically shut down in time when the set output torque value is reached. The output torque value is smaller than the torque value when the output head is stuck, and larger than the torque value when the operator uses the tool normally, thereby meeting the operator's usage needs and protecting the operator from tool damage.

[0048] It can be understood that before executing the method, that is, when the device is just powered on, the initialization of the central processing unit may specifically include initializing the clock module, GPIO module, timer module, ADC module, comparator module, PWM module, DAC module, etc.

[0049] Optionally, in some embodiments of the present application, Figure 3 , Figure 4 and Figure 5 As shown, in S110, obtaining the current operating parameters can be specifically achieved through the following steps: S111, the controller obtains its current bus voltage value and the current state information of the starting switch of the synchronous motor, and the state information indicates the current state of the controller.

[0050] S112: When the status information indicates that the controller is currently in the on state, the controller determines whether the enable flag of the synchronous motor is set.

[0051] S113, when it is determined that the enable flag of the motor is set, the controller obtains the bus current value and the current duty cycle.

[0052] Specifically, during the operation of the synchronous motor, the control system is powered on and initialized. After entering the working state, the voltage of the bus voltage after passing through the voltage divider resistor can be sampled through a channel of the ADC module to calculate the bus voltage value.

[0053] Furthermore, the operation of the start switch by the operator can be read through the GPIO module to determine whether the start switch is closed. The specific process is to determine whether the start switch is closed by reading the data bit information of a channel of the GPIO.

[0054] When it is determined through judgment that the read data result indicates that the start switch is closed at this time, such as the read data result is 0, which means that the operator inputs a message for turning on the controller by operating the button of the start switch, the next step S112 can be entered.

[0055] It can be understood that if the reading result is 1, it means that the starting switch of the synchronous motor is not closed at this time. If the read data result is 1, the shutdown action can be executed directly and the motor operation enable flag can be set; at this point, the shutdown from no torque sensor to the set torque value is completed.

[0056] That is, the controller can generate a shutdown control instruction to shut down the synchronous motor, and can further set the enable flag.

[0057] Further, in S112, when the acquired status information indicates that the current start switch of the controller is in the on state, the controller can obtain its current enable flag, and then determine whether the motor operation enable flag is set. If the enable flag is set, it means that the motor is allowed to run. At this time, the motor will be started and step S113 will be performed. It is understood that if the motor enable flag is not set, it means that the motor is not allowed to run, and the process can return to the step of obtaining the bus voltage value of the synchronous motor and the state information of the start switch, that is, enter the obtaining step of step S111 again, and return to execute the next cycle.

[0058] Further, in S113, bus current data of the controller can be obtained by sampling another ADC channel, and the current value can be obtained through calculation; and the current operation status information can be obtained, including the dimensionless duty cycle value d of the operation.

[0059] Optionally, in some embodiments of the present application, in S140, when the operating state of the synchronous motor at the next moment is determined using the determined output torque and the set torque threshold, the synchronous motor is controlled to stop running at the next moment or the output torque of the synchronous motor at the next moment is controlled.

[0060] The target operating state may include stopping operation or a target output torque.

[0061] That is, this step may specifically include: The torque threshold includes a set shutdown output torque value and a limited output torque value. Based on the set output torque threshold and the current output torque, determining the target operating state of the synchronous motor at the next moment includes: If the current output torque is greater than the set shutdown output torque value, the target operating state is determined to be shutdown; Or if the current output torque is greater than the limited output torque value, the target operating state is determined to be to reduce the current output torque.

[0062] Specifically, if the current output torque is greater than the set shutdown output torque value, the target operating state can be determined to be shutdown, that is, the shutdown operation can be performed at the next moment, such as Figure 4 shown.

[0063] Or if the current output torque is greater than the limited output torque value, the target operating state is determined to be to reduce the current output torque, that is, the operation of reducing the output torque can be performed at the next moment, such as Figure 5 shown.

[0064] Among them, the set shutdown output torque value or the limited output torque value range can be 20~28Nm.

[0065] It can be understood that the actual data can be flexibly adjusted according to the actual situation, and the embodiments of the present application are not limited to this.

[0066] Correspondingly, in some embodiments, Figure 4 As shown, when it is determined that the target operating state is shutdown, the method further includes: The controller generates a stop instruction and sends it to the motor drive module, so that the motor drive module responds to the stop instruction and controls the synchronous motor to stop running at the next moment.

[0067] For example, Figure 4 As shown, the current output torque is compared with the torque threshold, that is, the set shutdown output torque value. If the current output torque is greater than the set shutdown output torque value, a shutdown command can be generated according to the comparison result and sent to the motor drive module, so that the motor drive module responds to the control command and the synchronous motor stops running at the next moment.

[0068] Furthermore, during the control process, the central processing unit in the controller may also clear the enable flag of the synchronous motor and enter the next cycle again, that is, enter S110, to ensure the safety of the synchronous motor.

[0069] It can be understood that, if the current output torque is not greater than the set shutdown output torque value through comparison, the operation continues and enters the next cycle again, namely S110.

[0070] For example, Figure 5 As shown, in some embodiments, when it is determined that the target operating state is to reduce the output torque, the method further includes: The controller generates a control instruction and sends it to the motor drive module, so that the motor drive module responds to the control instruction, so that the synchronous motor reduces the duty cycle at the next moment and finally reduces the output torque.

[0071] For example, Figure 5 As shown, the current output torque is compared with the torque threshold, that is, the set limit output torque value. If the current output torque is greater than the set limit output torque value, the controller can generate a control instruction based on the comparison result and send it to the motor drive module, so that the motor drive module responds to the control instruction, so that the synchronous motor reduces the duty cycle at the next moment, thereby reducing the output torque.

[0072] Furthermore, in the above control process, when the method is executed, the central processing unit in the controller can also clear the enable flag of the synchronous motor and enter the next cycle again, that is, enter S110, to ensure the safety of the synchronous motor.

[0073] It can be understood that the synchronous motor control method for handheld power tools provided in the present application can be specifically applied to various types of handheld power tools, and can be specifically applied to water drills.

[0074] In practice, water drills have large torque, and handheld water drills are used directly by people, so protective measures are difficult to implement.

[0075] When the controller provided by the present application is used to execute the control method, the water drill does not need to be adjusted in speed after entering the steady-state operation. The output speed (motor speed) is automatically adjusted according to the load size, power and current limit.

[0076] That is, an appropriate protective torque can be set. The torque value is generally smaller than the holding force of a person. If the torque value is exceeded, the machine will be shut down directly to avoid injury to the user.

[0077] In order to better understand the protection of the tool by the control method of the present application, the test results of Table 1 and Table 2 are used to illustrate below.

[0078] Table 1 shows the operation test results of the water drill without the protection mechanism of the present application.

[0079] Table 1

[0080] It can be seen from Table 1 that when the torque protection value is not set, the tool torque, that is, the output torque reaches 25.86 Nm. That is, in the actual operation process, when the output torque is under this condition, if an accident such as a chuck occurs, there will be a very large safety hazard.

[0081] Table 2 shows the operation test results of the water drill using the protection mechanism of the present application.

[0082] Table 2

[0083] It can be seen from Table 2 above that when the torque protection value is set to 20 Nm and the dynamometer verification is performed again, when the torque reaches 19.88 Nm, the torque protection shutdown will be triggered, achieving the effect of high torque protection for handheld tools.

[0084] It can be understood that the handheld power tool motor control method provided in the embodiment of the present application collects the current operating parameters including bus voltage value, bus current value, duty cycle and commutation interval in real time through the central processing unit, and then determines the current input power and speed by processing the acquired operating parameters, and then searches for the output torque of the synchronous motor through a lookup table including the correspondence between input power, speed and output torque, and finally compares the determined output torque with the set torque threshold to implement the output torque control strategy or the set torque value shutdown function.

[0085] That is, through the control method provided in the embodiment of the present application, the machine can be automatically shut down in time when the set output torque value is reached. The output torque value is less than the torque value of the output head stuck, and greater than the torque value when the operator uses the tool normally, which can meet the operator's use needs and protect the operator from tool damage. On the other hand, the present application also provides a handheld electric tool synchronous motor control device, such as Figure 6 As shown, the device comprises: An acquisition module 210 is used to acquire its current operating parameters, wherein the operating parameters include bus voltage value, bus current value, duty cycle and commutation interval; A calculation module 220, configured to calculate the current input power of the synchronous motor according to the bus voltage value, the bus current value and the duty cycle, and calculate the current speed according to the commutation interval and the number of pole pairs of the synchronous motor; A search module 230, configured to search for the current input power and the output torque corresponding to the speed based on a set search table, wherein the search table includes a corresponding relationship between the input power of the controller, the motor speed, and the output torque of the synchronous motor; The decision module 240 is used to determine the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque.

[0086] Optionally, in the synchronous motor control device provided by the present application, the torque threshold includes setting a shutdown output torque value and a limited output torque value, and the decision module is specifically used for: If the current output torque is greater than the set shutdown output torque value, the target operating state is determined to be shutdown; Or if the current output torque is greater than the limited output torque value, the target operating state is determined to be to reduce the current output torque.

[0087] Optionally, the synchronous motor control device provided by the present application, when determining that the target operating state is shutdown, the device further includes: The first generating module 250 is used to generate a stop instruction and send it to the motor driving module, so that the motor driving module responds to the stop instruction and controls the synchronous motor to stop running at the next moment.

[0088] Optionally, the synchronous motor control device provided by the present application, when determining that the target operating state is to reduce the current output torque, the device further includes: The second generating module 260 is used to generate a control instruction and send it to the motor driving module, so that the motor driving module responds to the control instruction and reduces the output torque of the synchronous motor after reducing the duty cycle at the next moment.

[0089] Optionally, in the synchronous motor control device provided by the present application, the acquisition module is specifically used for: Obtain the bus voltage value of the synchronous motor and the status information of the start switch, where the status information indicates whether the synchronous motor is currently turned on or off; When the status information indicates that the synchronous motor is currently in the on state, determining whether an enable flag of the synchronous motor is set; When the enable flag is set, the current bus current value and the current duty cycle of the synchronous motor are obtained.

[0090] Optionally, in the synchronous motor control device provided by the present application, when the state information indicates that the synchronous motor is currently in a closed state, the acquisition module is further used to: A stop control instruction is generated to stop the synchronous motor and set the enable flag.

[0091] Optionally, in the synchronous motor control device provided by the present application, when the enable flag is not set, the acquisition module is further used to: Return to the step of obtaining the bus voltage value of the synchronous motor and the status information of the start switch.

[0092] In an exemplary embodiment, a controller is provided, wherein a central processing unit is configured. The central processing unit may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 7As shown. The central processing unit includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the central processing unit is used to provide computing and control capabilities. The memory of the central processing unit includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the central processing unit is used to store video tag processing data. The input / output interface of the central processing unit is used to exchange information between the processor and an external device. The communication interface of the central processing unit is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a synchronous motor control method is implemented.

[0093] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present application, and does not constitute a limitation on the central processing unit to which the scheme of the present application is applied. The specific central processing unit may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0094] In an exemplary embodiment, a central processing unit, namely a controller, is also provided, which includes a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0095] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0096] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0097] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0098] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0099] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for controlling a synchronous motor of a handheld electric tool, characterized in that: The method is used for a controller in a handheld electric tool, and the method comprises: The handheld electric tool controller obtains its current operating parameters, which include bus voltage value, bus current value, duty cycle and commutation interval; The controller calculates the current input power according to the bus voltage value, the bus current value and the duty cycle, and calculates the current rotation speed according to the commutation interval and the number of pole pairs of the synchronous motor of the handheld electric tool; The controller searches for the output torque corresponding to the current input power and the rotational speed based on a set lookup table, wherein the lookup table includes a correspondence between the input power of the controller, the rotational speed, and the output torque of the synchronous motor; The controller determines the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque, and the target operating state includes shutting down and reducing the current output torque.

2. The handheld electric tool synchronous motor control method according to claim 1, characterized in that: The torque threshold includes a set shutdown output torque value and a limited output torque value. The controller determines the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque, including: If the current output torque is greater than the set shutdown output torque value, determining the target operating state to be shutdown; Alternatively, if the current output torque is greater than the limited output torque value, the target operating state is determined to be to reduce the current output torque.

3. The handheld electric tool synchronous motor control method according to claim 2, characterized in that: When it is determined that the target operating state is shutdown, the method further includes: The controller generates a stop instruction and sends it to the motor drive module, so that the motor drive module responds to the stop instruction and controls the synchronous motor to stop running at the next moment.

4. The handheld electric tool synchronous motor control method according to claim 2, characterized in that: When it is determined that the target operating state is to reduce the current output torque, the method further includes: The controller generates a control instruction and sends it to the motor drive module, so that the motor drive module responds to the control instruction, so that the synchronous motor reduces the duty cycle at the next moment and reduces the output torque.

5. The handheld electric tool synchronous motor control method according to claim 2, characterized in that: The controller obtains its current operating parameters including: The controller obtains the current bus voltage value and the current state information of the start switch, wherein the state information indicates the current state of the controller; When the state information indicates that the controller is currently in an on state, determining whether an enable flag of the synchronous motor is set; When the enable flag is set, the current bus current value and the current duty cycle of the synchronous motor are obtained.

6. The synchronous motor control method for handheld electric tools according to claim 5, characterized in that: When the state information indicates that the synchronous motor is currently in a closed state, the method further includes: The controller generates a shutdown control instruction to stop the synchronous motor and set the enable flag.

7. The handheld electric tool synchronous motor control method according to claim 5, characterized in that: When the enable flag is not set, the method further includes: The controller returns to execute the step of acquiring the bus voltage value of the synchronous motor and the status information of the starting switch.

8. A synchronous motor control device for a handheld electric tool, characterized in that: The device comprises: An acquisition module is used to acquire its current operating parameters, wherein the operating parameters include bus voltage value, bus current value, duty cycle and commutation interval; A calculation module, used for calculating the current input power of the synchronous motor according to the bus voltage value, the bus current value and the duty cycle, and calculating the current speed according to the commutation interval and the number of pole pairs of the synchronous motor; A search module, used to search for the current input power and the output torque corresponding to the speed based on a set lookup table, wherein the lookup table includes a correspondence between the input power of the controller, the motor speed, and the output torque of the synchronous motor; The decision module is used to decide the target operating state of the synchronous motor at the next moment based on the set output torque threshold and the current output torque, and the target operating state includes shutting down and reducing the current output torque.

9. A handheld electric tool controller, characterized in that: The controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to implement the handheld power tool synchronous motor control method according to any one of claims 1-7.

10. A synchronous motor control system for a handheld electric tool, characterized in that: The control system comprises: A synchronous motor, power supply and controller assembly for a handheld power tool; the controller assembly comprises a motor drive module, a voltage sampling module, a current sampling module and the handheld power tool controller as claimed in claim 9; The voltage sampling module is used to collect the bus voltage value of the control system, the current sampling module is used to collect the bus current value of the control system, and the motor driving module is used to drive the synchronous motor; The controller is used to execute the handheld power tool synchronous motor control method as described in any one of claims 1-7.

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