Electric-motor control method and control apparatus, and electronic device and storage medium

Abstract

The present application relates to an electric-motor control method applied to an electric tool, and an electric-motor control apparatus, an electronic device and a storage medium. The electric-motor control method comprises: controlling the output of an electric motor by means of a vector control strategy; and switching the operating mode of the electric motor on the basis of output requirements of the electric motor, wherein the switching mode comprises automatic switching and / or manual switching, and the electric motor at least comprises a first operating mode and a second operating mode. In the present application, an operating mode is switched on the basis of output requirements of an electric motor, different vector control strategies are used to meet the requirements of the electric motor for various rotation speeds and various torque outputs without incurring extra hardware costs, and the defect of the electric motor being under a small load at a high rotation speed is overcome; and the present application is applicable to a wide range of operating scenarios, thereby expanding the operation range of the electric motor, and maximizing the performance of the electric motor.

Description

Motor control methods, control devices, electronic equipment and storage media Technical Field

[0001] This invention relates to the field of power tool technology, and more specifically to a motor control method, control device, electronic device, and computer storage medium for power tools. Background Technology

[0002] Currently, many motor control applications use field weakening control to achieve a higher speed range above the rated speed. However, this sacrifices some torque, leading to a deterioration in the motor's torque response and a decrease in its load-carrying capacity. In other applications, overmodulation is used to achieve higher load-carrying capacity; however, this sacrifices some speed regulation range and results in larger low-order current harmonics, causing torque pulsation.

[0003] Power tools are often used under various working conditions, which place different demands on the output capacity of the motor. However, there is a certain contradiction between the motor's output speed and torque, which prevents the motor from fully utilizing its performance under different working conditions.

[0004] Therefore, it is necessary to design a motor control scheme to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application provides an improved solution: a motor control method for power tools, comprising:

[0006] Obtain the motor's output requirements;

[0007] The output of the motor is controlled by a vector control strategy, which includes at least a first vector control strategy and a second vector control strategy.

[0008] According to the output requirements and switching method of the motor, the working mode of the motor is switched and the output of the motor is adjusted. The switching method includes at least one of automatic switching and manual switching.

[0009] The motor includes at least a first operating mode and a second operating mode. In the first operating mode, the motor adopts a first vector control strategy and outputs a first speed and a first torque.

[0010] In the second operating mode, the motor adopts the second vector control strategy, and the motor outputs a second speed and a second torque; wherein the first vector control strategy and the second vector control strategy are different.

[0011] In an optional embodiment, the method provided in this application for obtaining the output demand of the motor includes:

[0012] Get the maximum values ​​of the motor speed and torque input by the user;

[0013] The input requirements for the motor are generated based on the maximum values ​​of the motor's speed and torque input by the user.

[0014] In an optional embodiment, the method provided in this application for obtaining the output demand of the motor includes:

[0015] The current and speed of the motor are monitored in real time;

[0016] The output requirements of the motor are determined based on the relationship between the current and the threshold current and the relationship between the rotational speed and the threshold rotational speed.

[0017] In an optional embodiment, when the motor is in the first operating mode, the first speed is the rated speed and the first torque is the rated torque in the method provided by this application.

[0018] In an optional embodiment, when the motor is in the second operating mode, the second vector control strategy provided in this application includes at least a vector control combining field weakening and overmodulation, the second speed is greater than the rated speed, and the second torque is greater than the rated torque.

[0019] In an optional embodiment, the motor in the method provided by this application further includes a third operating mode. When the motor is in the third operating mode, a third vector control strategy is adopted. The third vector control strategy includes at least field weakening vector control. The motor outputs a third speed and a third torque. The third speed is greater than the rated speed, and the third torque is the rated torque.

[0020] In an optional embodiment, the motor in the method provided by this application further includes a fourth operating mode. When the motor is in the fourth operating mode, a fourth vector control strategy is adopted. The fourth vector control strategy includes at least overmodulation vector control. The motor outputs a fourth speed and a fourth torque. The fourth speed is the rated speed, and the fourth torque is greater than the rated torque.

[0021] In an optional embodiment, the automatic switching method provided in this application specifically includes:

[0022] The current and speed of the motor are detected in real time, and the output requirements of the motor are determined based on the relationship between the current and the threshold current, and the relationship between the speed and the threshold speed.

[0023] Based on the analysis of the motor's output requirements, the real-time current and speed of the motor are obtained;

[0024] Based on the real-time current and speed of the motor, a matching operating mode is determined, and the motor is automatically switched to the corresponding operating mode. The vector control strategy corresponding to the operating mode is then used to control the motor.

[0025] In an optional embodiment, the manual switching method provided in this application specifically includes:

[0026] The output requirements of the motor are manually identified.

[0027] Analyze the output requirements of the motor to determine the maximum speed and maximum torque required by the motor;

[0028] Select the corresponding operating mode based on the maximum speed and maximum torque, and generate an operating mode switching command;

[0029] The motor receives the working mode switching command, controls the motor to switch to the working mode, and uses the vector control strategy corresponding to the working mode to control the motor.

[0030] In an optional embodiment, the method provided in this application for switching the operating mode of the motor includes:

[0031] If the output demand of the motor is indicated as rated speed and rated torque, then the first operating mode is selected so that the motor adopts the first vector control strategy in the first operating mode;

[0032] If the output demand of the motor indicates high speed and high torque, select the second operating mode so that the motor adopts the second vector control strategy in the second operating mode;

[0033] If the output demand of the motor is indicated as high speed and rated torque, the third operating mode is selected so that the motor adopts the third vector control strategy in the third operating mode;

[0034] If the output demand of the motor is indicated as rated speed and high torque, the fourth operating mode is selected so that the motor adopts the fourth vector control strategy in the fourth operating mode.

[0035] This application also provides a motor control device, the control device comprising:

[0036] A detection unit used to detect the output requirements of a motor;

[0037] A working mode switching unit is used to switch the working mode according to the output demand of the motor. The working mode switching unit includes one of an automatic switching unit and a manual switching unit.

[0038] A processing unit that communicates with the operating mode switching unit and employs any of the motor control methods described above.

[0039] In an optional embodiment, the working mode switching unit in the method provided in this application includes an automatic switching unit and / or a manual switching unit.

[0040] In an optional embodiment, the detection unit in the apparatus provided in this application is used for:

[0041] Get the maximum values ​​of the motor speed and torque input by the user;

[0042] The input requirements for the motor are generated based on the maximum values ​​of the motor's speed and torque input by the user.

[0043] In an optional embodiment, the detection unit in the apparatus provided in this application is used for:

[0044] The current and speed of the motor are monitored in real time;

[0045] The output requirements of the motor are determined based on the relationship between the current and the threshold current, and the relationship between the rotational speed and the threshold rotational speed.

[0046] In an optional embodiment, when the motor is in the first operating mode, the first speed is the rated speed and the first torque is the rated torque in the device provided by this application.

[0047] In an optional embodiment, when the motor is in the second operating mode, the second vector control strategy of the device provided in this application includes at least vector control combining field weakening and overmodulation, the second speed is greater than the rated speed, and the second torque is greater than the rated torque.

[0048] In an optional embodiment, the motor in the device provided by this application further includes a third operating mode. When the motor is in the third operating mode, a third vector control strategy is adopted. The third vector control strategy includes at least field weakening vector control. The motor outputs a third speed and a third torque. The third speed is greater than the rated speed, and the third torque is the rated torque.

[0049] In an optional embodiment, the motor in the device provided by this application further includes a fourth operating mode. When the motor is in the fourth operating mode, a fourth vector control strategy is adopted. The fourth vector control strategy includes at least overmodulation vector control. The motor outputs a fourth speed and a fourth torque. The fourth speed is the rated speed, and the fourth torque is greater than the rated torque.

[0050] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the motor control method described in any of the preceding claims.

[0051] A computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the motor control method according to any one of the preceding claims.

[0052] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described motor control method.

[0053] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described motor control method.

[0054] Compared with the prior art, the present invention has the following beneficial effects: The motor control method for power tools provided in this application switches the working mode according to the output demand of the motor and adopts different vector control strategies to meet the requirements of the motor for multiple speeds and multiple torque outputs without increasing the additional hardware cost. It overcomes the defect of the motor having a small load at high speeds, is suitable for a wider range of working scenarios, expands the operating range of the motor, gives full play to the performance of the motor, and effectively saves costs. Attached Figure Description

[0055] Figure 1 is a schematic flowchart of a motor control method provided in this application;

[0056] Figure 2 is a schematic diagram of a first vector control strategy adopted when a motor is in a first working mode, as provided in this application;

[0057] Figure 3 is a schematic diagram of a second vector control strategy used when a motor is in a second working mode, as provided in this application;

[0058] Figure 4 is a schematic diagram of the output waveform provided in this application when the input is a step response;

[0059] Figure 5 is a schematic diagram of a motor coordinate vector provided in this application;

[0060] Figure 6 is a schematic diagram of a third vector control strategy used when a motor is in the third working mode, as provided in this application;

[0061] Figure 7 is a schematic diagram of an SVPWM voltage vector provided in this application;

[0062] Figure 8 is a schematic diagram of a fourth vector control strategy used when a motor is in the fourth working mode, as provided in this application;

[0063] Figure 9 is a flowchart illustrating an automatic switching of working modes provided in this application;

[0064] Figure 10 is a schematic diagram of a motor control device provided in this application. Detailed Implementation

[0065] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0066] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," and "rear" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0067] In many motor control applications, field weakening control is used to achieve higher speed ranges above the rated speed. However, this sacrifices some torque, leading to a deterioration in the motor's torque response and reduced load-carrying capacity. In other applications, over-modulation is used to achieve higher load-carrying capacity; however, this sacrifices some speed regulation range and results in larger low-order current harmonics, causing torque ripple. Therefore, a control method is needed to overcome the motor's limitation of low load capacity at high speeds and to meet the motor's requirements for various speeds and torque outputs.

[0068] The present invention solves the problems of the prior art by adopting the following technical solution: a motor control method for power tools, as shown in Figure 1, comprising:

[0069] The output of the motor is controlled by a vector control strategy, which includes at least a first vector control strategy and a second vector control strategy.

[0070] The operating mode of the motor is switched according to the output requirements of the motor. The switching method includes automatic switching and / or manual switching. The motor includes at least a first operating mode and a second operating mode. In the first operating mode, the motor adopts the first vector control strategy and outputs a first speed and a first torque. In the second operating mode, the motor adopts the second vector control strategy and outputs a second speed and a second torque. The first vector control strategy and the second vector control strategy are different.

[0071] When the motor is in the first operating mode, the first speed output by the motor is the rated speed, and the first torque output by the motor is the rated torque.

[0072] Furthermore, the rated speed and rated torque mentioned above are fixed characteristic parameters of the motor and are related to the motor's performance.

[0073] The first speed is the maximum speed that the motor can output in the first working mode, and the first torque is the maximum torque that the motor can output in the first working mode. The motor can output the first speed and the first torque simultaneously.

[0074] Specifically, as shown in Figure 2, a schematic diagram of the first vector control strategy is given when the motor is in the first operating mode, with a given speed ω. ref The difference between the feedback speed ω and the speed ω is used as the input to the speed regulator, and its output is the q-axis current setpoint i. qref With feedback i q The difference is taken as i q The input and output of the current regulator are V. q The given i of the d-axis current dref =0 and feedback i d The difference is taken as i d The input of the current regulator. Its output is V. d V d and V q Both are used as inputs to the inverse Park transform, and their output is V. α and V β The output is then sent to the three-phase inverter via the SVPWM (Space Vector Pulse Width Modulation) module, and the three-phase inverter output drives the motor. The motor's position signal is obtained from a position sensor and processed by a speed calculation module to obtain the feedback speed ω. The three-phase current i is obtained through sampling. A i B i C The output i is obtained after Clarke transformation. α i β After undergoing Park transformation, the output i d i q .

[0075] The first working mode described above is applicable to rated load and rated speed conditions. When the load characteristics and speed requirements of the motor are not high, the first vector control strategy is adopted to perform vector control on the motor in a simple and efficient manner to execute the corresponding work.

[0076] When the motor is in the second operating mode, the second vector control strategy includes at least vector control combining field weakening and overmodulation, the second speed output by the motor is greater than the rated speed, and the second torque output by the motor is greater than the rated torque.

[0077] The second speed is the maximum speed that the motor can output in the second operating mode, and the second torque is the maximum torque that the motor can output in the second operating mode. The motor can output the second speed and the second torque simultaneously.

[0078] Specifically, as shown in Figure 3, a schematic diagram of the second vector control strategy is given when the motor is in the second operating mode. In the figure, ω ref ω is the speed setpoint; ω is the speed feedback output i through the speed regulator. qref1 ; For torque setting; the MTPA (Maximum Torque per Ampere) reference current calculation module is mainly used for switching between four modes: normal vector control mode, overmodulation, field weakening, and a combination of overmodulation and field weakening. Its inputs are three values: i after field weakening processing. dFW Torque setpoint Speed ​​error and i qref1 The output is i qref2 and i dref respectively with feedback i q and i d The difference is calculated, and the output passes through a PI (Proportional-Integral) current controller module to output V. q and V d After inverse Park transform, the output V is... α and V β Then, the modulus of the sum of its squares is compared with the modulated output V. αom and V βom The modulo difference of the sum of the squares of the two yields ΔV; this is then processed by the field weakening control module to output i. dFW V αom and V βom The voltage output after SVPWM modulation is sufficient for motor operation; the position sensor obtains the angle; Clarke transform and Park transform the i A i B i C Change to i α i β When transformed into i d i q .

[0079] The transfer function of the first-order inertial element, which includes a proportional element, in the field weakening control module is as follows:

[0080] Figure 4 shows a schematic diagram of the output waveform when the input is a step response.

[0081] The field weakening control module uses a first-order inertial element and a limiting element, where K p It mainly affects the utilization rate of steady-state bus voltage and reduces K. p It can increase the utilization rate of steady-state bus voltage, but if it is too small, it will reduce the available voltage in the current closed loop, affecting the current response; t p It mainly affects the transient response of field weakening control, reducing t p A smaller value can improve response, but too small a value will cause fluctuations in the weak magnetic current. Therefore, it can be said that fast torque response and high efficiency are contradictory. If the torque response requirement is reduced, K can be appropriately reduced. p This improves the bus voltage utilization rate and the efficiency of the field weakening control area.

[0082] Specifically, in the second vector control strategy, the voltage threshold is replaced by an overmodulated output, and the integral element is replaced by a first-order inertial element. In actual operation, K is adjusted... p and t T The value is used to adjust the interaction effect of magnetic weakening and overmodulation.

[0083] For example, K can be reduced when the load is only slightly above the rated load. p This improves bus voltage utilization and the efficiency of the field weakening control region. When the speed significantly exceeds the rated speed, t can be appropriately reduced. T Reasonable design of K p and t T This allows for maintaining the motor's high speed and high torque requirements as much as possible. Generally, a smaller K value is preferred. p The value should be set to maximize the utilization rate of the steady-state bus voltage, and then a suitable t should be selected. T To meet the combined requirements of field weakening control and overmodulation for speed and torque response.

[0084] In the aforementioned second vector control strategy, a vector control combining field weakening and overmodulation is employed, enabling the motor to simultaneously output a second speed exceeding the rated speed and a second torque exceeding the rated torque. In this embodiment, the second speed and second torque are not specific numerical values; the second speed refers to the output speed exceeding the rated speed, and the second torque refers to the output torque exceeding the rated torque. In this second operating mode, the motor can simultaneously achieve outputs exceeding both the rated speed and rated torque, expanding the motor's operating range, overcoming the motor's limitation of low load capacity at high speeds, fully utilizing the motor's performance, and meeting the demands of operating conditions with high load characteristics and high speed requirements.

[0085] Furthermore, the motor also includes a third operating mode. When the motor is in the third operating mode, a third vector control strategy is adopted. The third vector control strategy includes at least field weakening vector control. The motor outputs a third speed and a third torque. The third speed is greater than the rated speed, and the third torque is the rated torque.

[0086] The third speed is the maximum speed that the motor can output in the third operating mode, and the third torque is the maximum torque that the motor can output in the third operating mode. The motor can output both the third speed and the third torque simultaneously.

[0087] Specifically, the basic principle of field weakening can be understood through the following steady-state electrical balance equation of a permanent magnet synchronous motor:

[0088] Among them, u d u q These are the voltage components along the d-axis and q-axis, respectively; i d i q These are the current components along the d-axis and q-axis, respectively; R s L is the internal resistance of the motor. s ω is the inductance of the motor; e This refers to the motor's rotational speed; For the magnetic flux of the motor; u s The output voltage value is the bus voltage modulated by PWM, and its value cannot exceed the bus voltage.

[0089] Analysis of the above equation shows that when the motor operates at a certain speed and load torque, the voltage value u required for motor operation is... s It was then fixed. s byu d u q The sum of squares and modulo is obtained as u. q It accounts for a large proportion, u q Two of these parameters are related to rotational speed, and both of them consume electricity as rotational speed increases. To maintain u... s To achieve the goal of keeping the motor's operating speed unchanged and increasing it, the only option is to reduce the magnetic flux.

[0090] Figure 5 shows the motor coordinate vector diagram. The direction of the d-axis current is along the rotor position. When the d-axis current is positive, it increases the magnetic flux linkage. When the d-axis current is negative, the flux linkage will decrease. Furthermore, when the d-axis current is negative, the inductance L can also be reduced. s The voltage drop across is negative, effectively reducing u s Therefore, in practical applications, applying a negative current along the d-axis is the most effective way to reduce magnetic flux and increase the motor's operating speed.

[0091] Figure 6 shows a schematic diagram of the third vector control strategy when the motor is in the third operating mode. In the figure, V ref The voltage threshold value for enabling field weakening control; and Difference followed by integration Output limiting.

[0092] Normal operating mode: When below the rated speed, Less than V ref The difference is positive, and after integration, i dFW It's still a positive value, but since the maximum amplitude limit is 0, then i at this time... dFW =0, which is the same as the first vector control strategy in the first working mode mentioned above.

[0093] When the motor switches from normal operating mode to the third operating mode and adopts the third vector control strategy, i.e., field weakening control: when the motor increases from rated speed, Greater than V ref The difference is negative, and after integration, i dFW The output starts to show negative values, i dFW The output begins to slowly deflect towards a negative current, when i dFW When the voltage becomes negative, the magnetic flux is weakened, and the voltage consumed decreases. It gets smaller and eventually equals V. ref The difference becomes 0, the integral has no effect, i dFW When the magnetic field stabilizes at a negative value, the weak magnetic effect remains stable.

[0094] When the motor switches from the third operating mode to the normal operating mode: in the field weakening state, Approximately equal to V ref When the motor decelerates from high speed to rated speed, Starting less than V ref The difference becomes positive, and the negative d-axis current obtained after integration begins to gradually approach zero through the accumulation of positive values, as long as... Always less than V ref At that time, the effect of integration will inevitably cause the negative current on the d-axis to eventually become 0.

[0095] In this embodiment, the third speed is not a specific value; it refers to an output speed greater than the rated speed. In the third operating mode, the motor can output both rated torque and speed exceeding the rated speed, making it suitable for applications with low load characteristics but high speed requirements.

[0096] Furthermore, the motor also includes a fourth operating mode. When the motor is in the fourth operating mode, a fourth vector control strategy is adopted. The fourth vector control strategy includes at least overmodulation vector control. The motor outputs a fourth speed and a fourth torque. The fourth speed is the rated speed, and the fourth torque is greater than the rated torque.

[0097] The fourth speed is the maximum speed that the motor can output in the fourth operating mode, and the fourth torque is the maximum torque that the motor can output in the fourth operating mode. The motor can output both the fourth speed and the fourth torque simultaneously.

[0098] Figure 7 shows the SVPWM (Space Vector Pulse Width Modulation) voltage vector diagram. V1, V2, V3, V4, V5, and V6 represent the voltage vectors under six switching states of the inverter. They are interconnected to form a regular hexagon. The area inside the inscribed circle of the hexagon is the linear modulation region, and the area between the inscribed and circumscribed circles is the overmodulation region. If the reference voltage vector exceeds the linear modulation region in SVPWM modulation, the normal SVPWM modulation method will no longer be used; this region is called the overmodulation region. In engineering applications, to improve the utilization rate of the DC bus and increase the output voltage amplitude of the inverter, an overmodulation algorithm can be used to transition the inverter from the linear modulation region to a six-step stepped waveform operating state, controlling the inverter's voltage output in the overmodulation region. The introduction of SVPWM overmodulation technology in motor control improves the utilization rate of the DC bus voltage, resulting in a certain increase in the stator output voltage. This is significant for improving the motor's instantaneous overload capacity, accelerating the motor start-up process, and for field weakening control of the motor.

[0099] Figure 8 shows a schematic diagram of the fourth vector control strategy used when the motor is in the fourth operating mode. The fourth vector control strategy specifically includes: given speed ω ref The difference between the feedback speed ω and the speed ω is used as the input to the speed regulator, and its output is the q-axis current setpoint i. qref With feedback i q The difference is taken as i q The input and output of the current regulator are V. q The given i of the d-axis current dref =0 and feedback i d The difference is taken as i d The input of the current regulator. Its output is V. d V d and V q Both are used as inputs to the inverse Park transform, and their output is V. α and V β After passing through the modulation module, V is output.αom V βom The output is then sent to the three-phase inverter via the SVPWM module, and the three-phase inverter output drives the motor. The motor's position signal is obtained from a position sensor and processed by a speed calculation module to obtain the feedback speed ω. The three-phase current i is obtained through sampling. A i B i C The output i is obtained after Clarke transformation. α i β After undergoing Park transformation, the output i d i q The condition for switching to this mode is V. α and V β The synthesized vector extends beyond the linear working region.

[0100] In this embodiment, the fourth torque is not a specific value; it refers to the torque output exceeding the rated torque. In the fourth operating mode, the motor can achieve both rated speed output and torque output exceeding the rated torque, making it suitable for applications with high load characteristics but low speed requirements.

[0101] Furthermore, the motor's operating mode can be switched according to the motor's output requirements, with switching methods including automatic switching and manual switching.

[0102] When automatic switching is used, the current and speed of the motor are detected in real time. Based on the relationship between the current and the threshold current, and the relationship between the speed and the threshold speed, the output demand of the motor is determined. Based on the output demand, the motor is automatically switched to the corresponding working mode, and the vector control strategy corresponding to the working mode is used to control the motor.

[0103] Figure 9 shows a flowchart of the automatic switching of working modes. The automatic switching specifically includes: real-time detection of the motor's q-axis current i. q And the rotational speed ω, determine the current i q With threshold current Rotational speed ω and threshold rotational speed ω * The size relationship.

[0104] when ω≤ω * When the motor's operating mode is switched to the first operating mode, the first vector control strategy is adopted;

[0105] when ω>ω * When the motor's operating mode is switched to the second operating mode, the second vector control strategy is adopted.

[0106] when ω>ω *When the motor's operating mode is switched to the third operating mode, the third vector control strategy is adopted;

[0107] when ω≤ω * When the motor's operating mode is switched to the fourth operating mode, the fourth vector control strategy is adopted.

[0108] Specifically, threshold current and threshold rotational speed ω * These are preset values; no specific values ​​are set in this manual. In actual situations, these values ​​should be adjusted according to the characteristics of the motor.

[0109] By automatically switching working modes, it is intelligent and efficient, eliminating the need for users to make judgments based on actual working conditions, simplifying user operations and improving user experience.

[0110] When manual switching is used, the operator identifies the output requirements of the motor, determines the maximum speed and maximum torque required by the motor, selects the corresponding working mode based on the maximum speed and maximum torque, and generates a working mode switching command. The motor receives the working mode switching command and controls the motor to switch to the working mode, and uses the vector control strategy corresponding to the working mode to control the motor.

[0111] Specifically, when using power tools, if the usage scenario requires rated speed and rated torque, that is, when the requirements for speed and load are not high, the user can select the first working mode, and the motor adopts the first vector control strategy in the first working mode.

[0112] When the application scenario requires high speed and high torque, that is, when both speed and load requirements are high, the user can select the second working mode, in which the motor adopts the second vector control strategy.

[0113] When the application scenario requires high speed and rated torque, that is, when the speed requirement is high and the load requirement is not high, the user can select the third working mode. In the third working mode, the motor adopts the third vector control strategy.

[0114] When the application scenario requires rated speed and high torque, that is, when the speed requirement is not high but the load requirement is high, the user can select the fourth working mode. In the fourth working mode, the motor adopts the fourth vector control strategy.

[0115] Furthermore, a working mode switching unit can be set on the power tool, which may include buttons, a touch screen, etc. The user operates the working mode switching unit to select the working mode to meet different working conditions.

[0116] For example, when the given speed is less than or equal to the rated speed and the given torque is less than or equal to the rated torque, the user selects the first working mode. For instance, if the above control method is applied to a chainsaw, the chainsaw does not have high requirements for speed and torque when cutting small pieces of wood. The user can select the first working mode through the working mode switching unit to perform vector control of the motor in a simple and efficient way to execute the corresponding work.

[0117] When the given speed is greater than the rated speed and the given torque is greater than the rated torque, the user selects the second working mode. For example, when using a chainsaw to cut a large tree, the user can select the second working mode through the working mode switching unit. The vector control, which combines field weakening and overmodulation, keeps the motor in a state of high speed and high torque, avoiding stalling and easily cutting the log.

[0118] When the given speed is greater than the rated speed and the given torque is less than or equal to the rated torque, the user selects the third working mode. For example, when the above motor control method is applied to a hair dryer, the load requirement is small, but the speed requirement is high. The user selects the third working mode through the working mode switching unit, which uses weak magnetic vector control to allow the motor to run above the rated speed and increase the air volume.

[0119] When the given speed is less than or equal to the rated speed and the given torque is greater than the rated torque, the user selects the fourth working mode. For example, when the above motor control method is applied to a lawnmower, the lawnmower wheels are stuck in the dimpled grass, and the torque requirement is higher. The user selects the fourth working mode through the working mode switching unit, which uses overmodulated vector control to increase the output torque of the lawnmower's walking motor, allowing the lawnmower to easily cross the dimpled section of the road.

[0120] The motor control method provided in this application is not limited to the above examples. The four working modes provided by the above control method can be selected according to the actual situation, and one or more of them can be combined according to the working conditions. This application does not set any restrictions on the selection and combination of working modes.

[0121] As can be seen from the above, the motor control method disclosed in this invention switches the working mode according to the output demand of the motor and adopts different vector control strategies to meet the requirements of the motor for multiple speeds and multiple torque outputs without increasing the additional hardware cost. It overcomes the defect of the motor having a small load at high speeds, is suitable for a wider range of working scenarios, expands the operating range of the motor, gives full play to the performance of the motor, and effectively saves costs.

[0122] This application also discloses a motor control device, as shown in FIG10, the control device comprising:

[0123] A detection unit used to detect the output requirements of a motor;

[0124] Working mode switching unit for switching the working mode according to the output demand of the motor;

[0125] A processing unit that communicates with the working mode switching unit and employs the above-described motor control method.

[0126] Furthermore, the working mode switching unit includes an automatic switching unit and / or a manual switching unit.

[0127] When the working mode switching unit is set to an automatic switching unit, the working mode switching unit can be a hardware device with computing capabilities, such as a controller. The detection unit detects the current and speed of the motor in real time, determines the output demand of the motor based on the relationship between the current and the threshold current, and the relationship between the speed and the threshold speed, and automatically switches to the corresponding working mode according to the output demand, and uses the vector control strategy corresponding to the working mode to control the motor.

[0128] When the operating mode switching unit is set to a manual switching unit, the operating mode switching unit can be a button, touch screen, etc., for the user to select. The user identifies the output requirements of the motor, determines the maximum speed and maximum torque required by the motor, selects the corresponding operating mode based on the maximum speed and maximum torque, and generates an operating mode switching command. The motor receives the operating mode switching command and controls the motor to switch to the selected operating mode, using the vector control strategy corresponding to that operating mode to control the motor.

[0129] Specifically, when using power tools, if the usage scenario requires rated speed and rated torque, that is, when the requirements for speed and load are not high, the user selects the first working mode through the working mode switching unit, and the motor adopts the first vector control strategy in the first working mode.

[0130] When the application scenario requires high speed and high torque, that is, when both speed and load requirements are high, the user can select the second working mode through the working mode switching unit, and the motor adopts the second vector control strategy in the second working mode.

[0131] When the application scenario requires high speed and rated torque, that is, when the speed requirement is high and the load requirement is not high, the user selects the third working mode through the working mode switching unit. In the third working mode, the motor adopts the third vector control strategy.

[0132] When the application scenario requires rated speed and high torque, that is, when the speed requirement is not high but the load requirement is high, the user selects the fourth working mode through the working mode switching unit. In the fourth working mode, the motor adopts the fourth vector control strategy.

[0133] Therefore, the motor control device provided in this application can automatically switch or manually switch the working mode according to the output demand of the motor, and adopt different vector control strategies to meet the requirements of the motor for multiple speeds and multiple torque outputs without increasing the additional hardware cost. It is suitable for a variety of working scenarios, gives full play to the performance of the motor, expands the extreme working conditions of the motor, and improves the user experience.

[0134] This application also discloses an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program to implement the aforementioned motor control method. This electronic device is a computing device such as a server, desktop computer, tablet computer, cloud server, and mobile terminal. The memory can be a hard disk or RAM within the electronic device, or an external USB flash drive, plug-in hard disk, smart media card (SMC), secure digital card (SD), or flash card. The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0135] This application also discloses a computer-readable medium storing a computer program that, when executed by a processor, implements the aforementioned motor control method. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0136] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (tools), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0137] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0138] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0139] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A motor control method for power tools, characterized in that, The motor control method includes: acquiring the motor's output requirements; The output of the motor is controlled by a vector control strategy, which includes at least a first vector control strategy and a second vector control strategy; the operating mode of the motor is switched and the output of the motor is adjusted according to the output requirements and switching method of the motor, which includes at least one of automatic switching and manual switching. The motor includes at least a first operating mode and a second operating mode. In the first operating mode, the motor outputs a first speed and a first torque based on the first vector control strategy. In the second operating mode, the motor outputs a second speed and a second torque based on the second vector control strategy; wherein the first vector control strategy and the second vector control strategy are different.

2. The motor control method according to claim 1, characterized in that, The acquisition of the motor's output requirements includes: Get the maximum values ​​of the motor speed and torque input by the user; The input requirements for the motor are generated based on the maximum values ​​of the motor's speed and torque input by the user.

3. The motor control method according to claim 1, characterized in that, The acquisition of the motor's output requirements includes: The current and speed of the motor are monitored in real time; The output requirements of the motor are determined based on the relationship between the current and the threshold current and the relationship between the rotational speed and the threshold rotational speed.

4. The motor control method according to claim 1, characterized in that, When the motor is in the first operating mode, the first speed is the rated speed and the first torque is the rated torque.

5. The motor control method according to claim 1, characterized in that, When the motor is in the second operating mode, the second vector control strategy includes at least vector control combining field weakening and overmodulation, the second speed is greater than the rated speed, and the second torque is greater than the rated torque.

6. The motor control method according to claim 1, characterized in that, The motor in the method further includes a third operating mode. When the motor is in the third operating mode, a third vector control strategy is adopted. The third vector control strategy includes at least field weakening vector control. The motor outputs a third speed and a third torque. The third speed is greater than the rated speed, and the third torque is the rated torque.

7. The motor control method according to claim 1, characterized in that, The motor also includes a fourth operating mode. When the motor is in the fourth operating mode, a fourth vector control strategy is adopted. The fourth vector control strategy includes at least overmodulation vector control. The motor outputs a fourth speed and a fourth torque. The fourth speed is the rated speed, and the fourth torque is greater than the rated torque.

8. The motor control method according to claim 3, characterized in that, The automatic switching method includes: Analyze the output requirements of the motor to obtain the real-time current and speed of the motor; Based on the real-time current and speed of the motor, a matching operating mode is determined, and the motor is automatically switched to the corresponding operating mode. The motor is then controlled using the vector control strategy corresponding to the operating mode.

9. The motor control method according to claim 2, characterized in that, The manual switching method includes: Analyze the output requirements of the motor to determine the maximum speed and maximum torque required by the motor; Select the corresponding operating mode based on the maximum speed and maximum torque, and generate an operating mode switching command; The motor receives the working mode switching command, controls the motor to switch to the working mode, and uses the vector control strategy corresponding to the working mode to control the motor.

10. A motor control device, characterized in that, The control device includes: A detection unit used to detect the output requirements of a motor; A working mode switching unit is used to switch the working mode according to the output demand of the motor. The working mode switching unit includes at least one of an automatic switching unit and a manual switching unit. The processing unit communicates with the working mode switching unit and employs the motor control method described in any one of claims 1-9.

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