WO2024140217A1 - Power tool, garden tool, and electric drill - Google Patents

Abstract

A power tool, a garden tool, and an electric drill. The power tool (10) comprises: a housing (11) forming an accommodating space: a motor (25) arranged in the accommodating space and comprising a stator and a rotor; a functional element (12) connected to an output shaft of the motor (25) and capable of being driven by the motor (25); a power supply device (21) for supplying electric energy to the power tool (10); a driver circuit (23) which comprises a plurality of switching elements and is configured to drive the motor (25); a detection module (24) for detecting working parameters of the motor (25); and a controller (22) at least electrically coupled to the driver circuit (23) and the parameter detection module, wherein the controller (22) comprises: a flux linkage and torque setting unit (221) configured to set target values of torque and stator flux linkage of the motor; a flux linkage and torque estimation unit (222) configured to calculate actual values of the torque and the stator flux linkage of the motor according to the working parameters; a flux linkage and torque comparison unit (223) configured to compare the target values with the actual values; and a voltage vector generation unit (224) configured to output a voltage vector according to the comparison result of the flux linkage and torque comparison unit (223) so as to control ON states of the switching elements in the driver circuit (23).

Description

Power tools, garden tools and drills

This application claims priority to the Chinese patent application filed with the China Patent Office on December 29, 2022, with application number 202211703952.0. The entire contents of the above application are incorporated by reference into this application.

Technical Field

The present application relates to an electric tool, for example, an electric tool, a garden tool and an electric drill.

Background technique

Power tools usually use traditional square wave modulation to drive the internal motor, or use current vector control (Field-Oriented Control, FOC) to control the rotation of the motor, or use a combination of the two to control the operation of the motor.

However, under the traditional square wave modulation control mode, in one electrical cycle, the brushless motor has only six states, or the stator current has six states (the three-phase bridge arm has six switching states). Each current state can be regarded as a vector torque synthesized in one direction. The six vectors are regularly converted step by step, thereby driving the rotor to rotate, and the motor rotor will rotate synchronously. The traditional square wave control is simple to implement, but because it only has six discrete, non-continuous vector torques, this will make the motor inefficient. FOC control involves complex coordinate transformations, which is not conducive to achieving rapid response in motor control.

This section provides background information related to the present application which is not necessarily prior art.

Summary of the invention

One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide an electric tool using a direct torque control motor.

An electric tool comprises: a shell, configured to form a accommodating space; a motor, arranged in the accommodating space, comprising a stator and a rotor; a functional element, connected to the output shaft of the motor and capable of being driven by the motor; a power supply device, configured to provide electric energy to the electric tool; a drive circuit, electrically connected to the motor to drive the motor, the drive circuit comprising a plurality of switch elements; a detection module, configured to detect the working parameters of the motor; a controller, electrically coupled to at least the drive circuit and the parameter detection module; wherein the controller comprises: a flux and torque setting unit, configured to set a target value of the torque and stator flux of the given motor; a flux and torque estimation unit, configured to calculate the actual value of the motor torque and the stator flux according to the working parameters; a flux and torque comparison unit, configured to compare the target value with the actual value; a voltage vector generation unit, configured to output a voltage vector according to the comparison result of the flux and torque comparison unit to control the conduction state of the switch elements in the drive circuit.

An electric tool comprises: a motor, comprising a stator and a rotor; a power supply device, configured to provide electric energy to the electric tool; an operating component, configured to obtain user input; a drive circuit, electrically connected to the motor to drive the motor, the drive circuit comprising a plurality of switch elements; a detection module, configured to detect working parameters of the motor; a controller, electrically coupled to at least the drive circuit, the detection module and the operating component; the controller is configured to: control the switch elements in the drive circuit to change the conduction state according to the user input and the working parameters to drive the motor to operate; wherein the torque response time of the controller is less than or equal to 10 milliseconds.

An electric tool comprises: a functional element; a motor configured to drive the functional element, the motor comprising a stator and a rotor; a power supply device configured to provide electrical energy to the electric tool; a drive circuit electrically connected to the motor and the power supply device, the drive circuit comprising a plurality of switch elements; a controller electrically connected to the drive circuit and configured to output a control signal to the drive circuit to control the plurality of switch elements; when the electric tool is in a first operating stage, the drive circuit is controlled in a first control manner; when the electric tool is in a second operating stage, the drive circuit is controlled in a second control manner; wherein the first control manner is different from the second control manner, and one of the first control manner and the second control manner is direct torque control.

A garden tool comprises: a functional element; an auxiliary element; a first motor, configured to drive the functional element; a second motor, configured to drive the auxiliary element; a power supply device, configured to provide electrical energy to the garden tool; a first drive circuit, electrically connected to the first motor and the power supply device, and configured to drive the first motor; a second drive circuit, electrically connected to the second motor and the power supply device, and configured to drive the second motor; a control component, electrically connected to the first drive circuit and the second drive circuit, and configured to output a control signal to control the first drive circuit and the second drive circuit; controlling the first drive circuit in a first control mode, and controlling the second drive circuit in a second control mode, the second control mode being different from the first control mode; at least one of the first control mode and the second control mode is direct torque control.

An electric tool comprises: a brushless motor; a drive circuit, wherein the drive circuit is configured to provide operating power to the brushless motor, and the inverter circuit comprises a plurality of switching elements; a detection module, wherein the detection module is configured to obtain the operating parameters of the brushless motor; and a controller, wherein the controller is electrically coupled to the drive circuit and the detection module respectively, and the controller adopts closed-loop control; the controller is configured to: determine a first load point based at least on user input, determine a first flux and torque setting method corresponding to the first load point; output an adapted voltage vector to control the on-off of the plurality of switching elements based on a target value given by the first flux and torque setting method and a difference between the operating parameters; determine a change from the first load point to a second load point; determine a second flux and torque setting method corresponding to the second load point; output an adapted voltage vector to control the on-off of the plurality of switching elements based on a target value given by the second flux and torque setting method and a difference between the operating parameters.

An electric tool comprises: a brushless motor including a rotor and a stator; a power supply device, the power supply device being configured to supply power to the brushless motor; a drive circuit, the drive circuit being configured to provide operating power to the brushless motor; a detection module being configured to detect operating parameters of the brushless motor; and a controller being electrically coupled to the detection module and the inverter circuit; the controller comprising: a flux setting unit, configured to output a reference value of the stator flux; a flux estimation unit, configured to estimate an actual value of the stator flux according to the operating parameters; the controller being configured to control the drive circuit to drive the brushless motor in a closed-loop control manner at least according to a comparison result of the reference value and the actual value of the stator flux; wherein, when a target speed of the brushless motor is greater than or equal to a first speed threshold, the flux setting unit is further configured to reduce the reference value of the stator flux.

An electric tool comprises: a brushless motor including a rotor and a stator; a drive circuit, the drive circuit being configured to provide operating power to the brushless motor; a battery pack, at least configured to power the drive circuit; a detection module, configured to detect operating parameters of the brushless motor; and a controller, the controller being electrically connected to the battery pack and the drive circuit, respectively; the controller comprising: a flux setting unit, configured to output a reference value of the stator flux; a flux estimation unit, configured to estimate an actual value of the stator flux based on the operating parameters; the controller being configured to control the drive circuit to drive the brushless motor in a closed-loop control manner, at least based on a comparison result of the reference value and the actual value of the stator flux; wherein, when the output voltage of the battery pack is less than or equal to a first voltage threshold, the flux setting unit is further configured to reduce the reference value of the stator flux.

An electric tool comprises: a motor, comprising a rotor and a stator; a power supply device, configured to provide electrical energy to the motor; a drive circuit, comprising a plurality of switching elements; a detection module, configured to detect the working parameters of the motor; a controller, electrically connected to the power supply device and the inverter circuit; the controller comprises: a torque setting unit, configured to output a reference value of the torque of the motor; a torque estimation unit, configured to estimate the actual value of the torque of the motor based on the working parameters of the motor; the controller is configured to generate a voltage vector control in a hysteresis control manner based on at least a comparison result between the reference value and the actual value of the torque of the motor to control the drive circuit to drive the motor; in response to a braking signal, the reference value of the torque output by the torque setting unit is less than or equal to zero, thereby controlling the drive circuit to brake the motor.

An electric tool comprises: a motor, comprising a rotor and a stator; a power supply device, configured to provide electric energy to the motor; a drive circuit, comprising a plurality of switching elements; a detection module, configured to detect the operating parameters of the motor; and a controller, electrically coupled to the power supply device and the drive circuit; wherein the controller is configured to: determine the target torque and target stator flux of the motor; estimate the actual torque and actual stator flux of the motor according to the operating parameters; calculate a torque difference according to the target torque and the actual torque of the motor; calculate a flux difference according to the target stator flux and the actual stator flux of the motor; output a control signal according to at least the flux difference and the torque difference; and increase the target stator flux in response to a deceleration signal output by the operating component.

An electric tool comprises: a motor, comprising a rotor and a stator; a power supply device, configured to provide electric energy to the motor; a drive circuit, comprising a plurality of switch elements, the plurality of switch elements comprising an upper switch element and a lower switch element; a detection module, configured to detect the working parameters of the motor; a controller, electrically connected to the power supply device and the drive circuit, and configured to: determine the target torque and target stator flux of the motor; obtain the actual torque and actual stator flux of the motor according to the working parameters; compare the target torque with the actual torque, compare the target stator flux with the actual stator flux, and generate a control signal to control the on and off of the plurality of switch elements according to the comparison result; and in response to a braking signal, control the motor braking by increasing the target stator flux, setting the target torque to a negative value, and opening all the switch elements in all the drive circuits.

A power tool comprises: a motor, comprising a stator and a rotor; a power supply device, configured to provide electrical energy to the motor; a drive circuit, electrically connected to the motor to drive the motor, the drive circuit comprising a plurality of switch elements; a detection module, configured to obtain working parameters of the motor; and a controller, configured to control the drive circuit and configured to: set a reference value of the stator flux and a reference value of the torque of the motor; estimate actual values of the stator flux and the torque of the motor according to the working parameters of the motor; predict predicted values of the stator flux and the torque of the motor at the next moment at least according to the actual values of the stator flux and the torque of the motor; compare the predicted value of the stator flux with the reference value of the stator flux to obtain a flux difference; compare the predicted value of the torque of the motor with the reference value of the torque of the motor to obtain a torque difference; generate a control signal at least according to the flux difference and the torque difference to control the conduction state of the plurality of switch elements.

An electric tool comprises: a motor, comprising a stator and a rotor; a power supply device, configured to provide electrical energy to the motor; a drive circuit, electrically connected to the motor to drive the motor, the drive circuit comprising a plurality of switch elements; a controller, configured to control the drive circuit; the controller comprises: a torque difference calculation unit, configured to calculate the torque difference according to the target torque and actual torque of the motor; a flux difference calculation unit, configured to calculate the flux difference according to the target stator flux and actual stator flux of the motor; a voltage vector generation unit, configured to generate a control signal according to at least the torque difference, the flux difference and the angular position of the rotor, the control signal being used to control the plurality of switch elements; and at least one control method selected from sliding mode control, fuzzy logic control and artificial neural network control is used to adaptively adjust the target torque and the target stator flux.

An electric drill comprises: a functional element; a motor, configured to drive the functional element to rotate, the motor comprising a stator and a rotor; a power supply module, configured to supply power to the motor; a drive circuit, electrically connected to the motor and the power supply module, the drive circuit comprising a plurality of switch elements; a detection module, configured to detect operating parameters of the motor; a controller, electrically coupled to the drive circuit and the detection module, and configured to: set a target torque and a target stator flux of the motor; estimate an actual torque and an actual stator flux of the motor according to the operating parameters; calculate a torque difference according to the target torque and the actual torque of the motor; and calculate a torque difference according to the target stator flux and the actual stator flux of the motor. Calculate the flux difference; generate a control signal to control the drive circuit at least according to the flux difference and the torque difference; and control the motor to stop rotating when the actual torque of the motor is greater than or equal to the target torque.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an appearance structure diagram of an electric drill in one embodiment;

FIG2 is a block diagram of a circuit system of an electric tool in one embodiment;

FIG3 is a circuit diagram of a driving circuit in the circuit system shown in FIG2 ;

FIG4 is a block diagram of a circuit system of an electric tool in one embodiment;

FIG5 is a schematic diagram of a space voltage vector in one embodiment;

FIG6 is a diagram of a switch state selection table in one embodiment;

FIG. 7 is a schematic diagram showing the relationship between the stator flux and the motor speed in a control mode in an embodiment;

FIG8 is a block diagram of a circuit system of an electric tool in one embodiment;

FIG9 is a block diagram of a circuit system of an electric tool in one embodiment;

FIG10 is a block diagram of a circuit system of an electric tool according to an embodiment;

FIG. 11 is a block diagram of a circuit system of an electric tool according to an embodiment.

Detailed ways

Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above drawings.

In this application, the terms "comprises", "includes", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

In this application, the term "and/or" is a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/" in this application generally indicates that the related objects before and after are in an "and/or" relationship.

In the present application, the terms "connect", "combine", "couple", and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, direct connection refers to two parts or components being connected together without the need for an intermediate piece, and indirect connection refers to two parts or components being connected to at least one intermediate piece respectively, and the two parts or components being connected via the intermediate piece. In addition, "connect" and "couple" are not limited to physical or mechanical connection or coupling, and may include electrical connection or coupling.

In the present application, it will be understood by those of ordinary skill in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerances caused by manufacturing, assembly, and use associated with a specific value, etc. Such terms should also be considered to disclose a range defined by the absolute values of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values that do not use relative terms should also be disclosed as specific values with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

In this application, it will be understood by those skilled in the art that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limitations on the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element. It should also be understood that the directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, the bottom can include directly below, lower left, lower right, lower front, and lower back, etc.

In this application, the terms "controller", "processor", "central processing unit", "CPU", and "MCU" are interchangeable. When a unit "controller", "processor", "central processing unit", "CPU", or "MCU" is used to perform a specific function, unless otherwise specified, these functions can be performed by a single unit or multiple units.

In the present application, the terms “device”, “module” or “unit” may be implemented in the form of hardware or software to achieve specific functions.

In this application, the terms "calculate", "judge", "control", "determine", "identify", etc. refer to the operation of a computer system or similar electronic computing device (e.g., controller, processor, etc.) and process.

The power tool in the present application can be a handheld power tool, such as a drill, a pruning machine, a sander, etc. Alternatively, the power tool can also be a bench-type tool, such as a table saw, a miter saw, etc. Alternatively, the power tool can also be a hand-push power tool, such as a hand-push lawn mower, a hand-push snow blower. Alternatively, the power tool can also be a riding power tool, such as a riding lawn mower, a riding vehicle, an all-terrain vehicle, etc. Alternatively, the power tool can also be a robot tool, such as a lawn mowing robot, a snow sweeping robot, etc. In some embodiments, the power tool can be an electric drill, an electric light, an electric car, etc. In some embodiments, the power tool can also be a garden tool, such as a pruning machine, a hair dryer, a lawn mower, a chain saw, etc. Alternatively, the power tool can also be a decoration tool, such as a screwdriver, a nail gun, a circular saw, a sander, etc. In some embodiments, the power tool can also be a vegetation care tool, such as a lawn mower, a lawn mower, a pruning machine, a chain saw, etc. Alternatively, the power tool can also be a cleaning tool, such as a hair dryer, a snow blower, a cleaning machine, etc. Alternatively, the power tool may also be a drilling tool, such as a drill, a screwdriver, a wrench, an electric hammer, etc. Alternatively, the power tool may also be a sawing tool, such as a reciprocating saw, a jig saw, a circular saw, etc. Alternatively, the power tool may also be a bench tool, such as a bench saw, a miter saw, a metal cutter, an electric milling machine, etc. Alternatively, the power tool may also be a grinding tool, such as an angle grinder, a sander, etc. Alternatively, the power tool may also be other tools, such as a fan, etc. Of course, the load may also include other types of household electrical appliances. As long as these power tools can adopt the substantive content of the technical solution disclosed below, they can fall within the protection scope of this application.

1 , the electric tool 10 is described by taking an electric drill as an example. The electric tool 10 mainly includes: a housing 11, a functional element 12, a grip 13, an operating assembly 14, a motor 15, and a power supply device 16. Of course, the electric drill also includes a transmission mechanism, a drill bit, a circuit board, etc. (not exposed in the perspective of FIG. 1 ).

The housing 11 is formed with a grip 13 for a user to grip. Of course, the grip 13 can be a separate part. The housing 11 constitutes the main body of the power tool 10 and is configured to accommodate a motor 15, a transmission mechanism, and other electronic components such as a circuit board. The front end of the housing 11 is configured to mount a functional element 12.

The functional element 12 is configured to realize the function of the electric tool 10, and the functional element 12 is driven by the motor 15. For different electric tools 10, the functional elements are different. Exemplarily, for a grinding tool, the functional element 12 can be a grinding piece, such as a grinding disc or sandpaper, etc., for a cutting tool, the functional element 12 can be a cutting piece, such as a chain, a knife disc or a blade or a mowing rope, etc., for a cleaning tool, the functional element 12 can be a cleaning piece or a blowing and suction piece, such as a cleaning brush head, a hair dryer, etc., for a fastening tool, the functional element 12 can be a solid piece, such as a sleeve or a batch head, etc. In this embodiment, for an electric drill, the functional element 12 is a drilling piece, such as a drill bit (not shown), which is configured to realize the drilling function. The drill bit is operably connected to the motor 15, for example, the drill bit is electrically connected to the motor 15 through an output shaft and a transmission mechanism.

The operating component 14 can be operated by the user to control the operation of the power tool 10. Generally, the operating component 14 can be operated directly or indirectly by the user. In one embodiment, the operating component 14 can be a speed control component. Mechanism. The user can directly manually press or rotate or slide the part of the speed regulating mechanism 14 for user operation to control the operation of the power tool 10. The speed regulating mechanism 14 is at least configured to set the target speed of the motor 15, that is, the speed regulating mechanism 14 is configured to achieve speed regulation of the motor 15. The speed regulating mechanism 14 can be but not limited to a trigger, a knob, a switch, a sliding rheostat, etc. In the present embodiment, the speed regulating mechanism 14 is configured as a trigger structure. The above is only an exemplary description and does not constitute a limitation of the present application. In one embodiment, the operating component 14 may also include an Internet of Things module, which can communicate wirelessly with other external devices, so that the user can indirectly control the operation of the power tool 10 through other external devices. Exemplarily, the Internet of Things module can communicate with smart terminal devices such as smart phones using wireless communication methods such as Bluetooth and Wireless Fidelity (WiFi), so that the user can non-contactly control the power tool 10 or remotely control the power tool 10 based on the terminal application installed in the smart phone.

In this embodiment, the motor 15 may be a brushless motor. In one embodiment, the motor 15 may be an inner rotor motor. In one embodiment, the motor 15 may be an outer rotor motor. In one embodiment, the motor 15 may be a brushless motor.

The power supply device 16 is configured to provide electrical energy to the power tool 10. In the present embodiment, the power tool 10 electric drill is powered by the battery pack 16. Optionally, the power tool 10 further includes a battery pack coupling portion 17, configured to connect the battery pack 16 to the electric drill. In other embodiments, the power supply device 16 may also be an AC power supply. In other embodiments, the power tool 10 is powered by an AC power supply, which may be 120V or 220V AC mains electricity. The power supply device 16 includes a power conversion unit, which is connected to the AC power and configured to convert the AC power into electrical energy that can be used by the power tool 10.

In another embodiment of the present application, a handheld power tool includes a motor having a stator and a rotor; a motor drive shaft or output shaft driven by the motor rotor; a tool accessory shaft configured to support a tool accessory; and a transmission device configured to connect the motor output shaft to the tool accessory shaft to transmit the torque output by the motor to a functional element of the tool. The motor output shaft can be coaxial, substantially parallel, substantially perpendicular, or inclined with the axis of the functional element, without limitation.

In another embodiment of the present application, a garden tool, such as a vehicle-type lawn mower, includes a main body, at least one drive wheel or drive wheel group supported by the main body; a drive device, such as a motor, that provides torque to the at least one drive wheel or drive wheel group; and a circuit system that controls the motor drive operation, as will be described below.

Referring to FIG. 2 , a circuit system 20 of an embodiment of the electric tool 10 includes a power supply device 21, a controller 22, a drive circuit 23, a detection module 24, and a motor 25. The controller 22 may include a flux and torque setting unit 221, a flux and torque estimation unit 222, a flux and torque comparison unit 223, and a voltage vector generation unit 224. In some embodiments, the flux and torque setting unit 221 may also be referred to as a torque and flux setting unit or may be divided into two sub-units, namely, a flux setting unit and a torque setting unit. In addition, the flux and torque estimation unit 222 and the flux and torque comparison unit 223 may also adopt the above-mentioned Different descriptions may be used in different implementations of the present application.

In order to distinguish different embodiments, the present application may use different numbers for the same components in different embodiments, but they can be understood as the same components. For example, the power supply device 16 in Figure 1 and the power supply device 21 in Figure 2 both represent the power supply device of the power tool 10.

The power supply device 21 is configured to supply power to the power tool 10. In some embodiments, the power supply device 21 outputs direct current, and the power supply device 21 includes a battery pack. In other embodiments, the power supply device 21 outputs alternating current, and the alternating current power supply can be a 120V or 220V AC mains power supply. The alternating current is converted into electric energy that can be used by the power tool 10 by rectifying, filtering, dividing, and reducing the voltage of the AC signal output by the AC power supply through a hardware circuit. In this embodiment, the power tool 10 is powered by a battery pack, and the power supply device 21 includes a battery pack.

The detection module 24 can detect the working parameters of the motor 25, such as detecting at least one of the phase current, phase voltage, speed, torque, number of revolutions, rotor position, stator resistance and the like of the motor 25.

The drive circuit 23 may also be referred to as an inverter. The drive circuit 23 is electrically connected to the controller 22 and the motor 25, and can drive the motor 25 to run according to the control signal of the controller 22. For a three-phase motor, the drive circuit 23 is electrically connected to the three-phase winding of the motor 25, and is configured to transfer the current from the power supply device 21 to the stator winding to drive the motor 25 to rotate. In one embodiment, as shown in Figure 3, the drive circuit 23 includes a plurality of switch elements Q1, Q2, Q3, Q4, Q5, and Q6. Among them, Q1, Q3, and Q5 are high-side switch elements, and Q2, Q4, and Q6 are low-side switch elements. Any one-phase stator winding of the motor 25 is connected to a high-side switch element and a low-side switch element. The gate terminal of each switch element in the drive circuit 23 is electrically connected to the controller 22, and is configured to receive a control signal from the controller 22. The drain or source of each switch element is connected to the stator winding of the motor 25. The switch elements Q1-Q6 receive control signals from the controller 22 to change their respective conduction states, thereby changing the current loaded by the power supply device 21 on the stator winding of the motor 25. In one embodiment, the drive circuit 23 can be a three-phase bridge driver circuit including six controllable semiconductor power devices (such as field effect transistors (Field Effect Transistor, FET), bipolar junction transistors (Bipolar Junction Transistor, BJT), insulated gate bipolar transistors (Insulate-Gate Bipolar Transistor, IGBT), etc.). It can be understood that the above-mentioned switch elements can also be any other type of solid-state switches, such as insulated gate bipolar transistors (IGBT), bipolar junction transistors (BJT), etc.

In order to drive the motor 25 to rotate, the drive circuit 23 has multiple drive states, and the speed or direction of the motor 25 can be different in different drive states. In one embodiment, the drive circuit 23 usually has at least six drive states, and each switching of the drive state corresponds to a phase switching action of the motor. In one embodiment, the controller 22 can output a pulse width modulation signal to control the drive circuit 22 to switch the drive state, thereby changing the working state of the motor 25.

In this embodiment, the controller 22 can output a voltage vector to the drive circuit 23, directly The conduction state of the switch element in the circuit 23 is controlled. Among them, the voltage vector can be a space vector pulse width modulation (SVPWM) waveform of the voltage generated by the controller 22. In one embodiment, the controller 22 can calculate and control the torque of the motor 25 in the stator coordinate system. There is no need to decompose the current of the motor into torque and flux components, which eliminates the need for rotation transformation and current control, so that the torque control response time of the controller 22 is shorter and the complexity of motor control is reduced. In this embodiment, the mode in which the controller 22 directly controls the torque of the motor 25 can be called direct torque control (Direct Torque Control, DTC). In this embodiment, the torque response time in the direct torque control process is less than or equal to 10ms, for example, it can be 10ms, 9ms, 8ms, 7ms, 6ms, 5ms, 4ms, 3ms, 2ms, 1ms, etc.

2 and 4 , the flux linkage and torque setting unit 221 in the controller 22 can set the target value of the torque of the motor 25 and the target value of the stator flux The so-called target value can also be called a reference value, which can be the output torque and stator flux that the user expects the motor 25 in the tool to achieve when operating the power tool 10, and can also be understood as the user input generated by the user operating the operating component 14. Exemplarily, when the operating component 14 is a trigger, the user input is the stroke of the trigger, and the stroke of the trigger corresponds to the target value of the torque and stator flux that the motor 25 should output, or when the operating component 14 is a speed knob, the user inputs the gear position of the unadjusted knob, and the motor 25 has different torques and stator fluxes at different gears. In this embodiment, the target value of the stator flux is the amplitude of the stator flux. In this embodiment, the target value of the torque of the motor 25 can be obtained by the proportional-integral (PI) operation of the target speed, that is, after the user inputs the target speed, the flux and torque setting unit 221 determines the target value of the torque of the motor 25 through the PI operation. In one embodiment, the user can also directly set the target value of the torque of the motor 25 through the operating component 14. For example, in a riding electric device, the user directly sets the target torque by operating the pedal.

The flux and torque estimation unit 222 can estimate the actual value Te of the torque of the motor 25 _and the actual value of the stator flux according to the working parameters of the motor 25 detected by the detection module 24. The actual value of the stator flux also refers to the actual amplitude of the stator flux. In this embodiment, the flux and torque estimation unit 222 can estimate the actual value of the stator flux according to the stator resistance _Rs of the motor 25. In a specific implementation, the stator flux vector can be obtained by integrating the back electromotive force:

Among them, Rs _is the stator internal resistance, is the stator terminal voltage, is the stator flux, Is _is the stator current of the motor.

From the above formula, we can know that the back electromotive force of the stator winding can be expressed by the formula When the motor 25 is running at high speed, the back electromotive force of the stator winding is large, so even if There is a large deviation, and it will not affect the reverse current. The back electromotive force has a significant impact on the stator flux, and thus the impact on the stator flux is not significant. On the contrary, when the motor 25 is running at a low speed, the back electromotive force is small. If the deviation of the internal resistance R _s is large, it will have a significant impact on the back electromotive force, thereby affecting the accuracy of the stator flux calculation. In other words, the calculation of the stator flux at low speed is more critical. In order to obtain good performance at rest and low speed, a low-pass filter with a cutoff frequency of ω _f can be introduced to eliminate the integral drift caused by DC offset and measurement. The stator flux can thus be expressed as:

Where ω _{s is} the frequency of stator flux rotation. It can be seen from formula (3) that at low speed, the stator internal resistance is dominant. In fact, if the estimated stator internal resistance is greater than the actual resistance, the time constant of the following differential equation (4) obtained from formula (1) is negative, which will cause the motor 25 to lose control.

Among them, σ is the influence factor, _Ls is the stator inductance, _Lr is the rotor inductance, _Lm is the magnetizing inductance, is the rotor flux. As can be seen from the above formula, the accuracy of stator internal resistance detection directly affects the determination of the actual value of the stator flux of the motor at low speed. In one embodiment, the detection module 24 can be a resistance observer or an inductance observer. The use of a resistance observer can more accurately observe the stator resistance of the motor 25. In one embodiment, the power tool 10 can also be provided with a resistance cooling device, which is configured to dissipate heat from the stator of the motor 25.

In one embodiment, a fuzzy controller can also be used to estimate the magnitude of the stator internal resistance in real time through fuzzy control, and the working parameters of the motor 25 can be updated in real time with the real-time internal resistance value. For example, the phase and amplitude errors between the estimated stator flux and the stator flux after filtering can be used as input variables of the fuzzy controller. The output variable of the fuzzy controller is the rate of change generated by fuzzy reasoning and defuzzification. The accuracy of the internal resistance estimation can be ensured by continuously iterating the change amount until it is stable and the final change amount is zero.

The flux and torque comparison unit 223 can compare the above target value and the actual value to determine the difference between the actual stator flux and the target stator flux, and the difference between the actual torque and the target torque. In this embodiment, the flux and torque comparison unit 223 may include at least one hysteresis comparator. When the error between the actual value and the target value is within the tolerance range of the hysteresis comparator, the output of the comparator remains unchanged. Once this range is exceeded, the hysteresis comparator gives a corresponding value. In a specific implementation, the hysteresis comparator can perform hysteresis processing on the torque difference to obtain a torque control signal; the flux estimation value is compared with the given flux, and the flux control signal is obtained through the hysteresis comparator.

The voltage vector generating unit 224 can output a voltage vector according to the comparison result output by the flux linkage and torque comparing unit 223, that is, output an SVPWM signal to control the drive circuit 23 to change the conduction state. In a motor modulation cycle, that is, a 360° commutation cycle, the motor commutates once every 60° rotation of the rotor, and the interval from one commutation of the motor 25 to the next commutation is defined as the commutation interval. Each commutation interval corresponds to a sector interval shown in FIG5. Each sector interval corresponds to a switching state, and the space voltage vector can be understood as making the drive circuit 23 change its conduction state. The driving circuit 23 has voltage signals with different switch states. In this embodiment, the voltage vector generating unit 224 can actually include a DTC switch table as shown in FIG. 6, that is, a switch state selection table. represents the difference between the actual value and the target value of the stator flux, ΔT represents the difference between the actual value and the target value of the torque of the motor 25, and u0-u7 represents eight switching states, where u0 and u7 are both zero vectors, and their corresponding switching states are (0,0,0) or (1,1,1). In this embodiment, after determining the voltage vector, the voltage vector generating unit 224 can generate an SVPWM waveform through the inverter to control the operation of the motor 25.

In this embodiment, it can be considered that the controller 22 can generate a voltage vector control motor 25 in a hysteresis control manner according to the comparison result of the actual torque value and the target value, and the comparison result of the actual stator flux value and the target value.

When the power tool 10 is working in the light load stage, it can have a higher speed, and when working in the heavy load stage, it may require a larger output torque. That is to say, the controller 22 can control the motor 25 to change the output torque or change the speed according to the load condition of the power tool 10. In the vector control technology of the permanent magnet synchronous motor or the DC motor, the direct axis component will form two regions of magnetization (Id>0) and weak magnetization (Id<0) of the permanent magnet during movement. In the weak magnetization area, the DC component in the stator current of the motor will form a demagnetization effect, which can realize the weak magnetization high-speed operation of the motor 25.

In the direct torque control of the motor 25, a field weakening method can also be used to increase the speed of the motor 25. However, unlike the field weakening in the vector control method, in the direct torque control, the field weakening effect substantially the same as that in the appropriate control can be achieved by reducing the target value of the stator flux.

In one implementation, the controller 22 can reduce the reference value or target value of the stator flux when the target speed of the motor 25 is greater than or equal to the first speed threshold. Generally, the first speed threshold can be a higher speed value, which can be the highest speed that the power tool 10 can reach when not using weak magnetic field speed-up. The first speed thresholds corresponding to different types of power tools 10 may be different. For example, the first speed threshold of an electric drill may be 27000RPM. In one embodiment, after the electric drill adopts direct torque control and weak magnetic field speed-up, the speed can reach 35000RPM. In other words, when the target speed to be reached by the motor 25 is relatively large, the speed of the motor 25 can be increased by weak magnetic field so that the motor 25 can reach the target speed, and when the target speed is relatively small, weak magnetic field speed-up may not be used. The following describes the effect of using weak magnetic field acceleration in the DTC control method in combination with the planned change relationship between the stator flux and the speed of the motor 25. Referring to Figure 7, it is assumed that before time t1, the motor 25 runs stably at a speed of 1200 rpm. At time t1, the user operates the operating component 14 to give a target speed of 2200 rpm. Then, from time t1, the controller 22 starts to control the motor 25 to increase its speed. Assuming that at time t2, the speed of the motor 25 reaches the first speed threshold corresponding to the power tool 10, the controller 22 starts to reduce the target value of the stator flux, and controls the motor 25 to continue to accelerate in a weak magnetic field manner, and reaches the target speed of 2200 rpm at time t3.

When the operating component 14 of the electric tool 10 is a trigger, generally, as the trigger travel increases, the electric The larger the target speed of the motor 25 is, the greater the target speed of the motor 25 is. Therefore, in the second half of the trigger stroke, the target speed that the motor 25 needs to reach will be greater than or equal to the first speed threshold, and the controller 22 needs to reduce the target value of the stator flux to enhance the weak magnetic effect of the stator winding and increase the speed of the motor 25. In some special tools, the target speed that the motor 25 needs to reach may be smaller as the trigger stroke increases, and weak magnetic acceleration is required in the first half of the trigger stroke.

If the power supply device 21 is a battery pack or other energy storage device, as the battery pack is continuously discharged, its voltage will continue to decrease. After the voltage of the battery pack is lower than the rated voltage or lower than other preset values, the input power of the power tool 10 will decrease, and the speed of the motor 25 will decrease when the load remains unchanged. In this case, in order to increase the speed of the motor 25, the controller 22 can reduce the target value of the stator flux to enhance the weak magnetic effect of the stator winding and increase the speed of the motor 25. In one embodiment, when the output voltage of the battery pack is less than or equal to the first voltage threshold, the flux and torque setting unit 221 can reduce the target value of the stator flux to increase the speed of the motor 25. Among them, the first voltage threshold can be the rated voltage of the battery pack or the undervoltage threshold of the battery pack.

In one embodiment, the controller 22 can reasonably adjust the target value of the stator flux of the motor 25 according to the load condition of the tool to control the torque or speed actually output by the motor 25. For example, under light load conditions, the motor 25 can work at a high speed, while under heavy load conditions, the motor 25 needs to work at a low speed and high torque. That is to say, under light load conditions, the flux and torque setting unit 221 in the controller 22 can reduce the target value of the stator flux to increase the speed of the motor 25. Conversely, if the target value of the stator flux is increased and the weak magnetic effect is reduced, the speed of the motor 25 can also be reduced, or the torque of the motor 25 can be increased.

In one embodiment, the controller 22 can also increase the torque of the motor 25 by reducing the weak magnetic effect. In one embodiment, under heavy load conditions, the flux linkage and torque setting unit 221 can increase the target value of the stator flux linkage to increase the torque of the motor 25. For example, when the electric drill is drilling a hole in soft wood, the weak magnetic method can be used to increase the speed of the motor 25. When drilling hard materials such as steel plates, a larger output torque is required, and the weak magnetic effect can be reduced to increase the torque of the motor 25.

In one embodiment, the power tool 10 may be provided with a working condition identification module that can identify the current working condition of the power tool 10. Exemplarily, the working condition identification module can identify the working condition by identifying the output power of the motor 25, or by identifying the working condition through user input, or by identifying the working condition through the actual rotation speed of the motor 25.

When the speed of the motor 25 is increased, there will be some problems, such as the working noise of the power tool 10 will be greater. The controller 22 can balance the decibel of the noise and the speed of the motor 25 and set a speed. When the power tool 10 works at the set speed, the decibel of the noise is within the range that the human ear can tolerate. The flux and torque setting unit 221 can increase the target value of the stator flux and reduce the speed of the motor 25 so that the final speed of the motor 25 is basically consistent with the set speed.

In one embodiment, the controller 22 reduces the target value of the stator flux to control the motor flux weakening speed. During the process, the permanent magnet enters the weak magnetic field area, and the nonlinearity of the permanent magnet and silicon steel sheet of the motor 25 increases, which will cause the control accuracy of the motor 25 to decrease, thereby increasing the harmonics. In this embodiment, the controller 22 can reduce the weak magnetic field effect by increasing the target value of the stator flux, so that the motor 25 can work in the linear area as much as possible, thereby reducing harmonic interference and ensuring the control accuracy of the motor 25. In one embodiment, the controller 22 can detect the nonlinearity of the flux of the permanent magnet and silicon steel sheet of the motor 25, and increase the stator flux target value accordingly, so as to avoid the stator flux target value increasing too much to brake the motor 25, and at the same time avoid the stator flux target value increasing too little to achieve the effect of eliminating harmonics.

In one embodiment, the controller 22 can also adjust the target value of the stator flux based on the current operating conditions, noise decibels, harmonic size and other conditions of the power tool 10, so that the power tool 10 can meet the balance between noise and operating comfort under any operating conditions.

In one embodiment, the power tool 10 needs to increase the speed under some conditions, and needs to increase the output power under some conditions. In order to adapt to the different needs of the tool, the controller 22 can switch the control mode, for example, the control mode can be switched according to the change of the load point of the motor 25. Among them, the load point can be determined according to the application conditions of the target torque or target speed of the motor 25 input by the user, for example, high speed and low torque, high speed and high torque, low speed and low torque, and low torque and high torque. Among them, high and low in the embodiment of the present application are relative concepts rather than absolute values. The method of dividing the high and low speeds or torques corresponding to different power tools 10 is also different, and no absolute definition is made here.

Referring to the circuit system 30 shown in FIG8 , it includes: a power supply device 31, a controller 32, a drive circuit 33, and a motor 34. The controller 32 includes a flux estimation unit 321, a torque estimation unit 322, a torque setting unit 323, a flux setting unit 324, a speed regulator 325, a maximum torque flux ratio controller 326, a torque comparison unit 327, a flux comparison unit 328, and a switch table 329.

In this embodiment, the flux estimation unit 321 and the torque estimation unit 322 have the same function as the flux and torque estimation unit 222 in the above embodiment, and both determine the actual value _Te of the torque of the motor 25 and the actual value of the stator flux according to the working parameters of the motor 25. The two estimation units can be estimated by the same method as the flux and torque estimation unit 222, which will not be described in detail here. In an optional embodiment, the flux estimation unit 321 and the torque estimation unit 322 can also be combined into one estimation unit.

The torque setting unit 323 can determine the target value of the torque of the motor 25 according to the user input. The flux setting unit 324 can also determine the target value of the stator flux according to the user input. Exemplarily, the user input may be that the user operates the operating component to reach the corresponding target speed of the motor 25 in any state.

The speed regulator 325 can determine the target value of the torque of the motor 34 according to the actual speed n of the motor 34 and a given value of the speed of the motor 34 , ie, the target value n ^* .

The maximum torque flux ratio controller 326 can set the minimum stator flux ratio value that can enable the motor 34 to rotate at the target torque according to the target value of the torque of the motor 34. In torque control, in order to achieve a certain torque output, the stator flux may not be a uniquely determined value, that is, the stator flux values within a certain range can make the motor 34 have the same output torque. The maximum torque flux ratio controller 326 can control the motor 34 to output a certain torque with the minimum stator flux, thereby ensuring that the motor 34 has the maximum power.

Different from the above-mentioned embodiment, the circuit system 30 in this embodiment also includes a first switch S1 and a second switch S2. The controller 32 can determine the load point according to the user input, and then control the two switches S1 and S2 to change the switch state according to the load point or the change of the load point. For example, when the controller 32 determines that the power tool 10 is at the first load point according to the user input, the two switches S1 and S2 can be controlled to be in the first switch state, that is, switch S1 is connected to the torque setting unit 323, and S2 is connected to the flux setting unit 324. In this switch state, the controller 32 can set the target value of the torque by the torque setting unit 323 in the first torque and flux setting mode. The target value of the stator flux is given by the flux setting unit 324. In the first torque and flux setting mode, the controller 32 can increase the field weakening effect by reducing the stator flux target value, thereby increasing the speed of the motor 34. That is, the first torque and flux setting mode is consistent with the torque and flux setting mode in the above embodiment.

When the controller 32 determines that the power tool 10 changes from the first load point to the second load point, the two switches S1 and S2 can be controlled to switch to the second switch state, that is, S1 is connected to the speed regulator 325, and S2 is connected to the maximum torque flux ratio controller 326. The controller 32 can set the target value of the torque and stator flux in the second torque and flux setting method. In a specific implementation, the speed regulator 325 can set the target value of the motor torque according to the actual speed and target torque of the motor 34. The maximum torque flux ratio controller 326 can determine the minimum stator flux that enables the motor 34 to have the target torque according to the target torque and use it as the target value of the stator flux. Output to the flux comparison unit 328.

When the controller 32 determines that the power tool 10 changes from the second load point to the first load point, the two switches S1 and S2 can be controlled to switch to the first switch state, and the target values of the torque and stator flux are given in the first torque and flux setting method.

In this embodiment, the torque comparison unit 327 can compare the target value and the actual value of the torque to determine the difference between the two, and the flux comparison unit 328 can compare the target value and the actual value of the stator flux to determine the difference between the two. The controller 32 can determine the corresponding voltage vector in the switch table 329 corresponding to the two differences, and then generate an SVPWM control signal to control the operation of the motor 34.

This embodiment does not specifically limit the application conditions corresponding to the first load point and the second load point. For example, the first load point may be an application condition of high speed and low torque, the second load point may be an application condition of low speed and high torque, the change from the first load point to the second load point may be a change from a high speed and low torque application condition to a low speed and high torque application condition, and the change from the second load point to the first load point may be a change from a low speed and high torque application condition to a high speed and low torque application condition.

In the second torque and flux setting mode, the target value of the stator flux is less than or equal to the base value of the stator flux. The so-called reference value can be understood as the setting value of the stator flux in the factory setting parameters of the power tool 10. In the first torque and flux given mode, the target value of the stator flux is greater than or equal to the above reference value.

In this embodiment, the first torque and flux setting method can also be called weak magnetic setting, that is, a setting method for weak magnetic control of the motor, and the second torque and flux setting method can be called maximum torque flux ratio method, that is, a setting method that can ensure that the motor 34 has maximum output power.

The motor control also includes braking control of the motor 34. Generally, the motor braking can include coasting braking to disconnect the power supply, short-circuiting braking in which the upper switch element of the driving circuit is fully opened or the lower switch element is fully opened to short-circuit the winding of the motor 34, and negative torque braking in which the motor 34 is controlled to output negative torque.

In the control system 20 shown in FIG4 , the controller 22 can respond to the braking signal to make the target value or reference value of the torque output by the flux linkage and torque setting unit 221 less than or equal to zero, that is, control the motor 25 to brake with negative torque. Alternatively, in response to the braking signal, the flux linkage and torque setting unit 221 increases the target value of the stator flux linkage to reduce the weak magnetic effect and gradually reduce the speed of the motor 25 to zero.

In the control system 30 shown in FIG8 , the controller 32 can respond to the braking signal so that the target value or reference value of the torque output by the torque setting unit 323 is less than or equal to zero, that is, the motor 34 is controlled to brake with negative torque. In one embodiment, in response to the braking signal, the controller 32 can also cause the flux setting unit 324 to increase the target value of the stator flux, thereby reducing the weak magnetic effect and gradually reducing the speed of the motor 34 to zero. In the control system 30 shown in FIG8 , when the controller 32 responds to the braking signal, switches S1 and S2 are in the first switching state, and the speed regulator 325 and the maximum torque flux ratio controller 326 are disconnected from the electrical connection in the control system 30.

In this embodiment, the user can input a braking signal through the operating component 14, such as a switch disconnection operation or a knob reset to an initial position or a trigger reset to an initial position.

In one embodiment, different braking methods can be used in different stages of braking, for example, a sliding braking control method is used in the initial stage of braking, and then the given value of the stator flux is increased to quickly reduce the speed of the motor, or the target of the stator flux is set to a value less than or equal to zero to brake with negative torque. This application does not limit the division of braking stages and the braking methods used in different stages.

For ease of description, the following motor braking control is described by taking the control system 30 shown in FIG8 as an example. In this embodiment, in response to the braking signal, the reference value of the torque output by the torque setting unit 323 is less than or equal to zero, thereby controlling the motor 34 to brake.

Although negative torque can quickly brake the motor 34 , there are also some problems. For example, negative torque braking will cause the bus voltage of the motor 34 to rise, which will cause the motor 34 to heat up severely or damage the electronic components in the control system 30 that are energized for a long time.

In order to avoid the above problem, the target torque output by the torque setting unit 323 is less than or equal to zero. In the process of braking the motor 34 with negative torque, the controller 32 can detect the DC bus voltage value of the power tool 10. When the voltage is greater than or equal to the first voltage threshold, the target value of the stator flux output by the flux setting unit 324 can be increased, so that the kinetic energy of the brake is quickly dissipated in the motor 34 while maintaining precise torque control. Among them, the first voltage threshold can be a threshold range of the DC bus voltage, for example, it can be any value within plus or minus 10% of the power supply voltage. In this embodiment, the motor 34 is a low-power motor, and the impedance of the motor 34 is related to the corresponding rated current. The flux braking effect on the low-power motor is more obvious. The output power of the exemplary motor 34 is less than or equal to 15kw, for example, it can be 15kw, 10kw, 8kw, 5kw, etc.

In one embodiment, as shown in FIG9 , the control system 40 includes a power supply device 41, a controller 42, a detection module 43, a drive circuit 44, and a motor 45. In this embodiment, the control system 40 also includes a brake resistor 46, and a switch device 47. Among them, the controller 42 is consistent with the controller 32 or 22 in the above-mentioned embodiment, and may also include a torque and flux setting unit, a torque and flux estimation unit, a torque and flux comparison unit, and a switch table. Here, the unit modules in the controller 42 are not introduced in detail. The detection module 43 can detect the voltage on the DC bus of the power tool 10 and output it to the controller 42.

The brake resistor 46 can be electrically disconnected from the stator winding of the motor 45 through the switch device 47. In the present embodiment, the controller 42 responds to the brake signal, and the torque and flux setting unit controls the given value of the torque of the motor 45 to be less than or equal to zero, so as to brake the motor 45 with a negative torque. When the bus DC voltage of the power tool 10 is greater than or equal to the first voltage threshold, the controller 42 can control the switch device 47 to turn on, so that the brake resistor 46 is connected to the power bus 48, and the bus voltage is consumed by resistive heating. When the DC bus voltage is less than the first voltage threshold, the controller 42 can control the switch device 47 to disconnect, so as to disconnect the brake resistor 47 from the power bus 48. In the present embodiment, the size and power of the brake resistor 46 need to be large enough to dissipate the power generated during braking in the form of heat.

In one embodiment, as shown in FIG10 , the control system 50 includes a power supply device 51, a controller 52, a detection module 53, a drive circuit 54, and a motor 55. In this embodiment, the control system 50 also includes a supercapacitor 56 and a control switch 57 that can control whether the supercapacitor 56 is connected to the power bus 58. In the process of controlling the negative torque braking of the motor 55, the controller 52 can control the control switch 57 to be in a closed state, and the supercapacitor 56 is connected to the power bus 58 to absorb the energy during the braking process. When the motor 55 is operating normally, the controller 52 can control the control switch 57 to be disconnected so that the supercapacitor 56 is no longer connected to the circuit.

In one embodiment, the electric tool 10 can be a fixed torque electric drill, that is, the output torque of the electric drill during operation cannot exceed a preset constant torque, i.e., a target torque, and the drill will stop when the torque exceeds the preset constant torque. The direct torque control in the present application can compare the actual torque of the motor 55 estimated by the torque estimation unit 222 with the set target value. If the actual value is greater than or equal to the comparison value, the controller 52 controls the motor 55 to stop running. The way in which the controller 52 controls the motor 55 to stop rotating can include at least one of the sliding braking, negative torque braking, or short-circuit braking in the above-mentioned embodiments, which will not be described in detail here.

In one embodiment, a method for optimizing the accuracy of direct torque control is also provided. For ease of description, the control system 20 shown in FIG. 4 is used as an example in the following motor control. In this embodiment, the flux and torque setting unit 221 can set the target value of the stator flux and torque, i.e., the reference value, according to the user input, and the flux and torque estimation unit 222 can estimate the actual value of the stator flux and torque according to the working parameters of the motor 25. After determining the reference value and the actual value, the controller 22 does not immediately calculate the difference and generate the voltage vector, but predicts the predicted value of the stator flux and the motor torque at the next moment based on the current actual value, and replaces the actual value with the target value by the predicted value, and then generates the voltage vector according to the difference. In one embodiment, the voltage vector generating unit 224 can select a voltage vector or a switch state to input the driving circuit 23 in turn according to the space voltage vector diagram shown in FIG5 or the DTC switch state selection table shown in FIG6 to control the rotation of the motor 25. The detection module 24 can detect the working parameters of the motor 25, and then the flux and torque estimation unit 222 determines a corresponding set of torque and stator flux prediction values according to the current working parameters, until all the voltage vectors in the switch table control the operation of the motor 25 and obtain the prediction value. The controller 22 can determine a set of prediction values closest to the reference value among all the prediction values corresponding to all the voltage vectors, and compare the closest prediction value with the target value to make a difference, and determine the voltage vector for controlling the operation of the motor 25 according to the comparison result to control the operation of the motor 25. In one embodiment, after the controller 22 determines a set of prediction values closest to the reference value among all the prediction values corresponding to all the voltage vectors, it can directly use the voltage vector corresponding to the set of prediction values as the voltage vector for controlling the operation of the motor 25, and control the operation of the motor 25.

In this embodiment, the method by which the controller 22 determines the predicted value can be called an enumeration method, that is, all voltage vectors in the voltage vector table are used as control quantities to control the voltage operation and obtain the predicted value. In other embodiments, other prediction methods can also be used to obtain the predicted values of the torque and stator flux of the motor 25, and the predicted values are compared with the target values of the motor torque and stator flux, that is, the reference values, as actual values, and the motor 25 is controlled to work according to the comparison results.

In some embodiments, the voltage vector generation unit in the controller can also use at least one control method of sliding mode control, fuzzy logic control, and artificial neural network control to adaptively adjust the target torque and target stator flux values to optimize the accuracy of determining the voltage vector and improve the control accuracy of the motor operation using direct torque control.

In one embodiment, at different stages of the motor operation, the control system can use different control methods to drive the motor. Exemplarily, when the power tool is in the first operating stage, the controller drives the motor in a first control method, and when the power tool is in the second operating stage, the controller controls the drive circuit to drive the motor in a second control method. Among them, one of the first control method or the second control method is the direct torque control described in the above embodiment, and the other control method is different from the direct torque control method. That is to say, at different stages of the power tool, direct torque control and other control methods can be used in combination to control the operation of the motor, such as direct torque control and vector control combined or. The controller can determine whether the power tool is in the first operating stage or the second operating stage based on the load-related parameters of the motor. Operation stage. For example, the controller can determine the current working stage of the power tool based on at least one parameter such as the phase current, voltage, speed, torque or acceleration of the motor. In one embodiment, the controller can also determine the working stage of the power tool based on the parameters of the power supply device. For example, the controller can determine the current working stage of the power tool based on at least one of the temperature, voltage or current of the battery pack. In one embodiment, the working stage of the power tool can be understood as the working condition of the power tool, such as a light load condition, a medium load condition, a heavy load condition, a no-load condition, or a rated load condition, etc., which are not listed here one by one.

In one embodiment, there may be more than one motor in the power tool, such as a push power tool, such as a push lawn mower, a push snow blower; or a riding power tool, such as a riding lawn mower, a riding vehicle, an all-terrain vehicle, etc.; or a robot tool, such as a lawn mowing robot, a snow blower robot, etc. In one embodiment, the power tool is a garden tool, for example, including at least one of a self-propelled machine, a riding machine, an intelligent robot, a push machine, a backpack machine, a handheld machine, and a wheeled machine. In some large power tools, a first motor may be provided to provide driving force for the walking wheel, and a second motor may be provided to provide power for the functional element. The types of the two motors may be the same or different, for example, one motor is a hub motor and the other is a power assist motor that transmits driving force through a gearbox.

The two motors in the garden tool can correspond to different drive circuits respectively. The control system 60 shown in FIG. 11 includes: a power supply device 61, a control component 62, a first drive circuit 63, a first motor 64, a second drive circuit 65, and a second motor 66. The first drive circuit 63 is electrically connected to the first motor 64 to drive the first motor 64, and the second drive circuit 65 is electrically connected to the second motor 66 to drive the second motor 66. The control component 62 in the control system 60 can control the first drive circuit 63 in a first control mode and control the second drive circuit 65 in a second control mode, wherein at least one of the two control modes is direct torque control. In this embodiment, the control component 62 can include two controllers, namely a first controller 621 and a second controller 622. The two controllers can have the same hardware configuration or different hardware configurations. For example, both controllers can use a dedicated control chip (for example, a microcontroller unit (MCU)), or can integrate a random access memory (ROM) or a read-only memory (RAM) or other memory or an integrated timer.

The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims (73)

1. An electric tool, comprising:

   A housing is configured to form a receiving space:

   A motor, arranged in the accommodation space, comprising a stator and a rotor;

   a functional element connected to the output shaft of the motor and capable of being driven by the motor;

   a power supply device, configured to provide electrical energy to the electric tool;

   A driving circuit, electrically connected to the motor to drive the motor, the driving circuit comprising a plurality of switching elements;

   A detection module, configured to detect operating parameters of the motor;

   A controller, electrically coupled to at least the driving circuit and the parameter detection module;

   Wherein, the controller comprises:

   The flux and torque setting unit is set to set the target value of the torque and stator flux of the given motor;

   a flux and torque estimation unit configured to calculate the torque of the motor and the actual value of the stator flux according to the operating parameters;

   a flux and torque comparison unit, configured to compare the target value with the actual value;

   The voltage vector generating unit is configured to output a voltage vector according to the comparison result of the flux linkage and torque comparing unit to control the conduction state of the switch element in the driving circuit.
2. The electric tool according to claim 1, wherein the detection module includes a resistance observer, which is configured to observe the stator resistance; and the flux and torque estimation unit is configured to calculate the actual value of the stator flux based on the stator resistance.
3. The electric tool according to claim 1, wherein the voltage vector generating unit is configured to obtain the voltage vector by looking up a table according to the comparison result.
4. The power tool according to claim 1, wherein the torque response time is less than or equal to 10 ms.
5. The electric tool according to claim 2, further comprising a resistance cooling device configured to dissipate heat for the stator.
6. The electric tool according to claim 1 further includes an operating component configured to obtain user input; the flux and torque setting unit is configured to set target values of the torque and stator flux of the motor according to the user input.
7. The power tool according to claim 6, wherein the operating assembly includes a speed regulating mechanism.
8. The electric tool according to claim 7, wherein the speed regulating mechanism comprises a switch, a trigger, At least one of a knob and a sliding mechanism.
9. The electric tool according to claim 1, wherein the functional element comprises at least one of a grinding piece, a drilling piece, a cutting piece, a blowing and suction piece, a cleaning piece, and a fastener.
10. The power tool of claim 1, wherein the power supply device comprises a battery pack removably connected to the power tool.
11. An electric tool, comprising:

    An electric motor, including a stator and a rotor;

    A power supply device, configured to provide electrical energy to the electric tool;

    Operation component, set to obtain user input;

    A driving circuit, electrically connected to the motor to drive the motor, the driving circuit comprising a plurality of switching elements;

    A detection module, configured to detect operating parameters of the motor;

    a controller, electrically coupled to at least the driving circuit, the detection module and the operating component;

    The controller is configured to: control the switch element in the drive circuit to change the conduction state according to the user input and the operating parameter, so as to drive the motor to operate;

    Wherein, the torque response time of the controller is less than or equal to 10 milliseconds.
12. The power tool according to claim 11, wherein the controller uses direct torque control.
13. The electric tool according to claim 11, wherein the operating component includes at least one of a power switch, a gear selection switch, and an intelligent detection element.
14. The electric tool according to claim 11, wherein the controller comprises: a flux setting unit, configured to output a reference value of the stator flux; a flux estimation unit, configured to estimate an actual value of the stator flux according to the operating parameters; the controller is also configured to control the drive circuit to drive the motor in a closed-loop control manner at least based on a comparison result between the reference value and the actual value of the stator flux.
15. The electric tool according to claim 11, wherein the controller comprises: a torque setting unit, configured to output a reference value of the torque of the motor; a torque estimation unit, configured to estimate the actual value of the torque of the motor based on the working parameters of the motor; the controller is also configured to generate a voltage vector control circuit to drive the motor in a hysteresis control manner based on at least a comparison result between the reference value and the actual value of the torque of the motor.
16. The power tool according to claim 11, wherein the torque response time of the controller is less than or equal to 5 milliseconds.
17. An electric tool, comprising:

    Functional elements;

    A motor, configured to drive the functional element, the motor comprising a stator and a rotor;

    a power supply device, configured to provide electrical energy to the electric tool;

    A drive circuit, electrically connected to the motor and the power supply device, wherein the drive circuit includes a plurality of switch elements;

    a controller electrically connected to the drive circuit and configured to output a control signal to the drive circuit to control the plurality of switch elements; control the drive circuit in a first control manner when the power tool is in a first operation stage; and control the drive circuit in a second control manner when the power tool is in a second operation stage;

    The first control mode is different from the second control mode, and one of the first control mode and the second control mode is direct torque control.
18. The electric tool according to claim 17, wherein the controller is further configured to determine whether the electric tool is in the first operating stage or the second operating stage according to load-related parameters of the motor.
19. The electric tool according to claim 18, wherein the load-related parameters of the motor include at least one of the current, rotational speed, torque and acceleration of the motor.
20. The electric tool according to claim 17, wherein the controller is further configured to determine whether the electric tool is in the first operating stage or the second operating stage according to relevant parameters of the power supply device.
21. The electric tool according to claim 20, wherein the relevant parameters of the power supply device include at least one of temperature, voltage, and current of the power supply device.
22. The electric tool according to claim 17, wherein the functional element comprises at least one of a grinding piece, a drilling piece, a cutting piece, a blowing and suction piece, a cleaning piece, and a fastener.
23. The power tool according to claim 17, wherein the motor comprises an inner rotor motor or an outer rotor motor.
24. A garden tool, comprising:

    Functional elements;

    Auxiliary components;

    A first motor, configured to drive the functional element;

    a second motor configured to drive the auxiliary element;

    A power supply device, configured to provide electrical energy to the garden tool;

    a first drive circuit, electrically connected to the first motor and the power supply device, and configured to drive the first motor;

    a second drive circuit, electrically connected to the second motor and the power supply device, and configured to drive the second motor;

    A control component is electrically connected to the first drive circuit and the second drive circuit, and is configured to output a control signal to control the first drive circuit and the second drive circuit; control the first drive circuit in a first control mode, and control the second drive circuit in a second control mode, wherein the second control mode is different from the first control mode; and at least one of the first control mode and the second control mode is direct torque control.
25. The garden tool of claim 24, wherein the auxiliary element comprises a travel wheel set.
26. According to the garden tool of claim 25, wherein the walking wheel set comprises at least a driving wheel; and the first motor or the second motor is further configured to drive the driving wheel to rotate.
27. The garden tool according to claim 24, wherein the second motor is any one of a hub motor and a power-assisted motor.
28. The garden tool according to claim 24 further comprises at least one of a self-propelled machine, a riding machine, an intelligent robot, a push machine, a backpack machine, a handheld machine and a wheeled machine.
29. The garden tool according to claim 24, wherein the control assembly comprises a first controller and a second controller, the first controller is configured to control the first drive circuit, and the second controller is configured to control the second drive circuit.
30. The garden tool according to claim 29, wherein the hardware configurations of the first controller and the second controller are different.
31. An electric tool, comprising:

    Brushless Motor;

    a drive circuit configured to provide operating power to the brushless motor, the inverter circuit comprising a plurality of switching elements;

    A detection module, configured to obtain operating parameters of the brushless motor; and

    A controller, the controller is electrically coupled to the driving circuit and the detection module respectively, and the controller adopts closed-loop control;

    The controller is configured to: determine a first load point based at least on a user input, determine a load point corresponding to the The invention relates to a method for determining a first flux and torque given mode for the first load point; outputting an adapted voltage vector to control the on-off of the plurality of switch elements based on a target value given by the first flux and torque given mode and a difference between the operating parameters; determining a change from the first load point to a second load point; determining a second flux and torque given mode corresponding to the second load point; and outputting an adapted voltage vector to control the on-off of the plurality of switch elements based on a target value given by the second flux and torque given mode and a difference between the operating parameters.
32. The electric tool according to claim 31, wherein in the second flux and torque setting mode, the target value of the stator flux is less than or equal to the reference value of the stator flux.
33. The electric tool according to claim 31, wherein the second flux and torque setting method sets target values of the torque and stator flux of the motor according to the maximum torque flux ratio.
34. The electric tool according to claim 31, wherein in the first flux and torque setting mode, the target value of the stator flux is greater than or equal to the reference value of the stator flux.
35. The electric tool according to claim 31, wherein the controller is further configured to: determine the change from the second load point to the first load point; determine a first flux and torque given mode corresponding to the first load point, and based on the difference between the target value given by the first flux and torque given mode and the operating parameter, output an adapted voltage vector to control the on and off of the multiple switching elements.
36. The electric tool according to claim 31, wherein the controller is further configured to determine the first load point and the second load point based on at least one of the rotational speed and the torque of the brushless motor input by the user.
37. The power tool according to claim 31 further includes an operating component configured to obtain user input.
38. The power tool according to claim 37, wherein the operating assembly includes a speed regulating mechanism.
39. The power tool according to claim 38, wherein the speed regulating mechanism comprises at least one of a switch, a trigger, a knob, and a sliding mechanism.
40. An electric tool, comprising:

    A brushless motor, including a rotor and a stator;

    a power supply device, the power supply device being configured to supply power to the brushless motor;

    a drive circuit configured to provide operating power to the brushless motor;

    A detection module, configured to detect operating parameters of the brushless motor; and

    a controller, the controller being electrically coupled to the detection module and the inverter circuit;

    The controller comprises:

    A flux setting unit, configured to output a reference value of the stator flux;

    a flux estimation unit, configured to estimate an actual value of the stator flux according to the operating parameters;

    The controller is configured to control the drive circuit to drive the brushless motor in a closed-loop control manner at least according to a comparison result between a reference value and an actual value of the stator flux;

    Wherein, when the target speed of the brushless motor is greater than or equal to a first speed threshold, the flux setting unit is further configured to reduce a reference value of the stator flux.
41. The power tool according to claim 40 further includes an operating component configured to obtain user input; the controller is also configured to determine the target rotational speed based on the user input.
42. The power tool according to claim 41, wherein the operating component includes a trigger; and the user input is the travel of the trigger.
43. The power tool according to claim 41, wherein the operating component includes a speed control knob; and the user input is the gear position of the speed control knob.
44. The electric tool according to claim 41, wherein the operating component includes an Internet of Things module; and the user input is a remote control instruction obtained by the Internet of Things module.
45. The electric tool according to claim 40 further includes a noise identification module, which is configured to identify the working noise of the brushless motor; when the working noise is greater than or equal to a noise threshold, the flux setting unit is also configured to increase the reference value of the stator flux.
46. The power tool according to claim 40, wherein the brushless motor comprises an inner rotor motor or an outer rotor motor.
47. An electric tool, comprising:

    A brushless motor, including a rotor and a stator;

    a drive circuit configured to provide operating power to the brushless motor;

    a battery pack, configured at least to supply power to the drive circuit;

    A detection module, configured to detect operating parameters of the brushless motor; and

    A controller, the controller being electrically connected to the battery pack and the drive circuit respectively;

    The controller comprises:

    A flux setting unit, configured to output a reference value of the stator flux;

    a flux estimation unit, configured to estimate an actual value of the stator flux according to the operating parameters;

    The controller is configured to control the drive circuit to drive the brushless motor in a closed-loop control manner at least according to a comparison result between a reference value and an actual value of the stator flux;

    Wherein, when the output voltage of the battery pack is less than or equal to a first voltage threshold, the flux setting unit is further configured to reduce a reference value of the stator flux.
48. The electric tool according to claim 47, wherein the controller is further configured to output a voltage vector based at least on a comparison result between a reference value and an actual value of the stator flux to control a conduction state of a switching element in the drive circuit.
49. The electric tool according to claim 47, wherein the controller is further configured to look up a switching table based on at least a comparison result between a reference value and an actual value of the stator flux to obtain a voltage vector and control a conduction state of a switching element in the drive circuit.
50. According to the electric tool according to claim 47, the controller further includes: a torque setting unit, configured to output a reference value of the torque of the motor; a torque estimation unit, configured to estimate the actual value of the torque of the motor based on the working parameters of the motor; the controller is also configured to generate a voltage vector control circuit to drive the motor in a hysteresis control manner based on at least a comparison result between the reference value and the actual value of the torque of the motor.
51. The electric tool according to claim 50, wherein the controller is further configured to output the voltage vector based on a comparison result between a reference value and an actual value of the stator flux, and based on a comparison result between a reference value and an actual value of the torque of the motor.
52. An electric tool, comprising:

    An electric motor, including a rotor and a stator;

    a power supply device configured to provide electrical energy to the motor;

    A driving circuit including a plurality of switching elements;

    A detection module, configured to detect the working parameters of the motor;

    a controller, electrically connected to the power supply device and the inverter circuit;

    The controller comprises:

    A torque setting unit, configured to output a reference value of the torque of the motor;

    a torque estimation unit, configured to estimate an actual value of the torque of the motor according to the working parameters of the motor;

    The controller is configured to generate a voltage vector to control the drive circuit to drive the motor in a hysteresis control manner at least according to a comparison result between a reference value and an actual value of the torque of the motor;

    In response to the braking signal, the reference value of the torque output by the torque setting unit is less than or equal to zero, thereby controlling the drive circuit to brake the motor.
53. The electric tool according to claim 52, wherein the controller further comprises: a magnetic flux A stator unit is configured to output a reference value of the stator flux; a flux estimation unit is configured to estimate an actual value of the stator flux according to the working parameters of the motor; and the controller is further configured to control the drive circuit to drive the motor in a hysteresis control manner according to a comparison result between the reference value and the actual value of the stator flux.
54. The electric tool according to claim 53, wherein the controller is further configured to output a voltage vector based on a comparison result between a reference value and an actual value of the stator flux and a comparison result between a reference value and an actual value of the torque of the motor to control the drive circuit to brake the motor.
55. The electric tool according to claim 52, wherein when the DC bus voltage of the electric tool is greater than or equal to a first voltage threshold, the reference value output by the flux given unit increases.
56. The electric tool according to claim 52 further includes a braking resistor, which is configured to be electrically connected to the stator winding of the motor in a detachable manner via a switching device, and when the DC bus voltage of the electric tool is greater than or equal to a first voltage threshold, the controller is configured to turn on the switching device to connect the braking resistor to the power bus.
57. The electric tool according to claim 52 further includes a supercapacitor, and during the braking process of the drive motor, the current generated by the rotation of the rotor flows to the supercapacitor.
58. An electric tool, comprising:

    An electric motor, including a rotor and a stator;

    a power supply device configured to provide electrical energy to the motor;

    A driving circuit including a plurality of switching elements;

    A detection module, configured to detect the working parameters of the motor;

    a controller electrically coupled to the power supply device and the drive circuit;

    Wherein, the controller is configured as:

    Determining a target torque and a target stator flux of the motor;

    estimating the actual torque and the actual stator flux of the motor according to the operating parameters;

    Calculating a torque difference according to the target torque of the motor and the actual torque;

    Calculating a flux difference according to a target stator flux of the motor and the actual stator flux;

    outputting a control signal at least according to the flux difference and the torque difference;

    In response to the deceleration signal output by the operating component, the target stator flux is increased.
59. The electric tool according to claim 58, wherein the output power of the motor is less than or equal to 15kw.
60. The electric tool according to claim 58 further includes an operating component configured to obtain user input; and a flux and torque setting unit configured to set target values of the torque and stator flux of the motor based on the user input.
61. The power tool according to claim 60, wherein the operating assembly includes a speed regulating mechanism.
62. The electric tool according to claim 61, wherein the speed regulating mechanism comprises at least one of a switch, a trigger, a knob, and a sliding mechanism.
63. An electric tool, comprising:

    An electric motor, including a rotor and a stator;

    a power supply device configured to provide electrical energy to the motor;

    A driving circuit, comprising a plurality of switch elements, wherein the plurality of switch elements include an upper switch element and a lower switch element;

    A detection module, configured to detect the working parameters of the motor;

    A controller is electrically connected to the power supply device and the driving circuit and is configured to:

    Determining a target torque and a target stator flux of the motor;

    Acquiring the actual torque and the actual stator flux of the motor according to the operating parameters;

    Comparing the target torque with the actual torque, comparing the target stator flux with the actual stator flux, and generating a control signal to control the on and off of the plurality of switch elements according to the comparison result;

    In response to the braking signal, the motor braking is controlled by increasing the target stator flux, setting the target torque to a negative value, and opening all the switch elements in all the drive circuits.
64. The power tool according to claim 63, wherein the braking response time of the controller is less than or equal to 10 ms.
65. An electric tool, comprising:

    An electric motor, including a stator and a rotor;

    a power supply device, configured to provide electrical energy to the motor;

    A driving circuit, electrically connected to the motor to drive the motor, the driving circuit comprising a plurality of switching elements;

    A detection module, configured to obtain operating parameters of the motor; and

    A controller is provided to control the driving circuit and is configured to:

    Setting a reference value of the stator flux and a reference value of the torque of the motor;

    estimating actual values of the stator flux and the torque of the motor according to the operating parameters of the motor;

    Predicting predicted values of the stator flux and the torque of the motor at a next moment based at least on actual values of the stator flux and the torque of the motor;

    Comparing the predicted value of the stator flux with the reference value of the stator flux to obtain a flux difference;

    Comparing the predicted value of the torque of the motor with the reference value of the torque of the motor to obtain a torque difference;

    A control signal is generated at least according to the flux difference and the torque difference to control the conduction state of the plurality of switch elements.
66. According to the electric tool according to claim 65, the controller is further configured to: calculate multiple predicted values of the stator flux and the torque of the motor at the next moment based on the actual values of the stator flux and the torque of the motor and the multiple switching states of the drive circuit; and select the switching state among the multiple switching states that minimizes the difference between the predicted values of the stator flux and the torque of the motor and the reference values of the stator flux and the torque of the motor to control the multiple switching elements.
67. The electric tool according to claim 65, wherein the controller is further configured to obtain a voltage vector by looking up the table according to the flux difference and the torque difference to control the conduction state of the multiple switching elements.
68. An electric tool, comprising:

    An electric motor, including a stator and a rotor;

    a power supply device, configured to provide electrical energy to the motor;

    A driving circuit, electrically connected to the motor to drive the motor, the driving circuit comprising a plurality of switching elements;

    A controller configured to control the drive circuit;

    The controller comprises:

    a torque difference calculation unit, configured to calculate a torque difference according to a target torque and an actual torque of the motor;

    a flux difference calculation unit configured to calculate a flux difference according to a target stator flux and an actual stator flux of the motor;

    A voltage vector generating unit is configured to generate a control signal based on at least the torque difference, the flux difference and the angular position of the rotor, wherein the control signal is used to control the multiple switching elements; and to adaptively adjust the target torque and the target stator flux by using at least one control method selected from sliding mode control, fuzzy logic control and artificial neural network control.
69. The electric tool according to claim 68, wherein the voltage vector generating unit is further configured to calibrate the voltage vector by using at least one of sliding mode control, fuzzy logic control, and artificial neural network control. The control signal is output after the torque difference or the flux difference is corrected.
70. An electric drill, comprising:

    Functional elements;

    A motor, configured to drive the functional element to rotate, the motor comprising a stator and a rotor;

    A power supply module, configured to supply power to the motor;

    A drive circuit, electrically connected to the motor and the power supply module, wherein the drive circuit includes a plurality of switch elements;

    A detection module, configured to detect operating parameters of the motor;

    A controller is electrically coupled to the driving circuit and the detection module and is configured to:

    Setting a target torque and a target stator flux of the motor;

    estimating the actual torque and the actual stator flux of the motor according to the operating parameters;

    Calculating a torque difference according to the target torque of the motor and the actual torque;

    Calculating a flux difference according to a target stator flux of the motor and the actual stator flux;

    generating a control signal to control the drive circuit at least according to the flux difference and the torque difference;

    When the actual torque of the motor is greater than or equal to the target torque, the motor is controlled to stop rotating.
71. The electric drill according to claim 70 further includes an operating component configured to obtain user input, and the controller is configured to set the target torque or the target stator flux based on the user input.
72. An electric drill according to claim 71, wherein the operating component includes a torque adjustment device for a user to operate to set a desired torque; and the controller is configured to determine the target torque based on the desired torque.
73. The electric drill according to claim 70, wherein the torque response time of the motor is less than or equal to 2 ms.