TWI723912B - Electric tool and its control method - Google Patents

Abstract

An electric tool includes a motor, a first circuit board, and a second circuit board. The first circuit board is provided with a first control device. The first control device is electrically connected to the motor. The second circuit board is electrically connected through a transmission line. Connected to the first circuit board, the transmission line group includes a command transmission line; the second circuit board is provided with a second control device. The control method of the electric tool includes: using the pulse width modulation signal generated by the second control device to represent different pulse signal frequencies as different rotation modes, and transmitting the pulse width modulation signal through the command transmission line, which is analyzed by the first control device The pulse width modulates the pulse signal frequency of the signal, and controls the motor in the corresponding rotation mode. In this way, the number of transmission lines in the transmission line group can be reduced.

Description

Electric tool and its control method

The present invention relates to electric tools; in particular, it refers to an electric tool that uses pulse width modulation signals to change the rotation mode and a control method thereof.

Figures 1 and 2 show a conventional electric tool 1, which includes a housing 10, a motor 14, an upper circuit board 16 and a lower circuit board 18. The housing 10 has a transmission portion 102 and a hand-held portion 104 , The transmission part 102 is provided with a motor 14 and a driving mechanism (not shown), the motor 14 is a three-phase DC brushless motor; the handheld part 104 is provided with an operation interface 12, the operation interface 12 for personnel to operate to generate an operation signal .

The upper circuit board 16 is arranged on the transmission part 102, and the upper circuit board 16 is arranged with six commutation switch elements 162, three Hall sensors 164, and the commutation switch element 162 is used to control the commutation of the motor. The sensor 164 senses the position of the rotor of the motor 14.

The lower circuit board 18 is disposed in the handle 104 of the casing 10, the lower circuit board 18 is electrically connected to the battery connection port 20 to receive power from the battery 22, and a controller 182 is disposed on the lower circuit board. The lower circuit board 18 is electrically connected to the operation interface 12 so that the controller 182 receives operation signals from the operation interface 12. The lower circuit board 18 is electrically connected to the upper circuit board 16 through a transmission line group 24. The transmission line group includes nine control signal transmission lines that transmit the control signals of the commutation switch elements 162, and transmit and transmit the output signals of the Hall sensors 164. Five position signal transmission lines. After the lower controller 182 receives the operation signal from the operation interface 12, it generates a control signal for controlling the commutation switching elements 162 according to the operation signal and the output signals of the Hall sensors from the five position signal transmission lines, and passes the nine control signals. The signal transmission line is transmitted to the commutation switching elements 162 of the upper circuit board 16 to control the commutation switching elements 162 to perform commutation and make the rotor of the motor 14 rotate.

Since the transmission line group 24 between the upper circuit board 16 and the lower circuit board 18 requires at least 14 transmission lines, the arrangement of 14 transmission lines in the limited space of the housing 10 will cause overcrowding, which is not conducive to the wiring of the transmission line group 24 during assembly. .

In view of this, the purpose of the present invention is to provide a transmission line group capable of reducing the number of transmission lines.

In order to achieve the above-mentioned object, the present invention provides an electric tool including a motor, a first circuit board and a second circuit board, wherein the first circuit board is provided with a first control device, and the first control device electrically Is electrically connected to the motor; the second circuit board is electrically connected to the first circuit board through a transmission line set, wherein the transmission line set includes a command transmission line; the second circuit board is provided with a second control device, the second control The device generates a pulse width modulation signal according to one of a plurality of different rotation modes, and transmits the pulse width modulation signal through the command transmission line, wherein the generated pulse width modulation signal has a plurality of different frequencies One of the pulse signal frequencies of, and the pulse signal frequencies respectively correspond to the rotation modes; the first control device receives the pulse width modulation signal, and analyzes the pulse width modulation signal to obtain a corresponding pulse Signal frequency, and control the corresponding action of the motor according to a rotation mode corresponding to the acquired pulse signal frequency.

The present invention also provides a control method of an electric tool, which includes the following steps:

Choose one of a plurality of different rotation modes;

The second control device generates a pulse width modulation signal according to the selected rotation mode, and transmits the pulse width modulation signal through the command transmission line, wherein the generated pulse width modulation signal has a plurality of different frequencies One of the pulse signal frequencies, and the pulse signal frequencies correspond to rotation modes respectively;

The first control device receives the pulse width modulation signal, analyzes the pulse width modulation signal to obtain a corresponding pulse signal frequency, and controls the motor corresponding to a rotation mode corresponding to the obtained pulse signal frequency Action.

The effect of the present invention is that the different pulse signal frequencies of the pulse width modulation signal generated by the second control device represent different rotation modes, and the first control device analyzes the pulse signal frequency of the pulse width modulation signal and uses The corresponding rotation mode controls the motor, so that the number of transmission lines in the transmission line group can be reduced, which is beneficial to the wiring of the transmission line group in the housing.

In order to explain the present invention more clearly, preferred embodiments are described in detail in conjunction with the drawings as follows. Please refer to Figures 3 and 4, which is a first preferred embodiment of the power tool 2 of the present invention. It includes a housing 30 and a motor 32 arranged in the housing 30, a first circuit board 36, and a first circuit board 36. Two circuit board 40, of which:

The rotating shaft 322 of the motor 32 is connected to a transmission member 34. The transmission member 34 uses an impact mechanism as an example in this embodiment, but is not limited to this, and may also be a clutch mechanism, a deceleration mechanism, and the like. The motor is a three-phase DC brushless motor in this embodiment.

A first control device 38 is provided on the first circuit board 36, and the first control device 38 is electrically connected to the motor 32. In this embodiment, the first control device 38 includes a plurality of commutation switching elements 382, a plurality of Hall sensors 384, and a first controller 386. The first controller 386 may be a microcontroller, The first controller 386 is electrically connected to the commutation switching elements 382 and the Hall sensors 384. In this embodiment, the commutation switching elements 382 are six MOSFETs and are electrically connected to the stator of the motor 32. , The Hall sensors 384 are three and each is used to sense the position of the rotor of the motor, and the output of each Hall sensor 384 is at a first voltage level and a second voltage level When the rotor rotates at 120 degrees, the Hall sensors output pulse waves in sequence to form a position signal in the form of pulse waves. In this embodiment, the first voltage level is taken as an example of a low voltage level, and the second voltage level is taken as an example of a high voltage level.

The first control device 38 includes a first storage unit 388. In this embodiment, the first storage unit 388 is a built-in memory of the first controller 386. The first storage unit 388 stores a plurality of control parameters. A controller 386 controls the commutation switching elements 382 according to the control parameters, thereby controlling the rotation of the shaft 322 of the motor 32. Each control parameter is used to control the motor to rotate in one of a plurality of different rotation modes. The rotation mode can be, for example, a forward rotation mode and a reverse rotation mode.

The second circuit board 40 is electrically connected to a battery 46 and an operation interface 48, and a second control device 42 and a display 44 are provided on the second circuit board 40. The battery 46 provides power to the second circuit board 40. The operation interface 48 is electrically connected to the second control device 42 and includes an activation switch 482 and a mode selector 484. The activation switch 482 is operated by the user to output an activation signal to the The second control device 42, the mode selector 484 can be a switch and is operated by the user to output a selection signal to the second control device 42. The second control device 42 includes a second controller 422 and a second storage unit 424. The second controller 422 can be a microcontroller and is electrically connected to the display 44. In this embodiment, the second storage unit 424 is a built-in memory of the second controller 422, and the second storage unit 424 stores a plurality of frequency parameters, and the frequency parameters respectively correspond to a plurality of different pulse signal frequencies. The second controller 422 can select a corresponding frequency parameter according to the selected signal, and generate a pulse width modulation signal having a specific frequency of the pulse signal according to the selected frequency parameter.

The second circuit board 40 is electrically connected to the first circuit board 36 through a transmission line set 50. The transmission lines of the transmission line set 50 include a power line 501, a ground line 502, a command transmission line 503, a brake signal line 504, and a The feedback signal line 505, a current signal line 506, and a speed signal line 507. The power line 501 and the ground line 502 are used to transmit power from the second circuit board 40 to the first circuit board 36. The second control device 42 and the first control device 38 communicate through the command transmission line 503, the brake signal line 504, the feedback signal line 505, the current signal line 506, and the speed signal line 507.

The second control device 42 transmits a pulse width modulation signal to the first control device 38 via the command transmission line 503 as a command for controlling the rotation mode of the motor 32. The aforementioned operation mode will be described in detail later.

The second control device 42 transmits a braking command via the braking signal line 504, and the first control device 38 controls the motor 32 to stop rotating according to the braking command.

The first control device 38 transmits a corresponding feedback signal via the feedback signal line 505. The feedback signal corresponds to the actuation state of the transmission member 34. For example, when the impact mechanism is activated, the feedback signal sent by the first control device 38 is A plurality of pulse waves represent the number of impacts of the impact mechanism. In one embodiment, the feedback signal line 505 may not be provided.

The first control device 38 detects the current when the motor 32 is running, and transmits a motor current signal through the current signal line 506.

The first controller 386 converts the position signals sensed by the three Hall sensors 384 into a rotation speed signal. The rotation speed signal is transmitted to the second control device 42 through the rotation speed signal line 507 for the second control device 42 to determine The speed of the motor 32. Please cooperate with FIG. 5, in this embodiment, when the output of each Hall sensor 384 is changed from the first voltage level V1 to the second voltage level V2, the first controller 386 changes the speed signal from A third voltage level V3 is changed to a fourth voltage level V4, and the output of the first controller 386 at each Hall sensor 384 is changed from the second voltage level V2 to the first voltage At the level V1, the rotation speed signal is changed from the fourth voltage level V4 to the third voltage level V3. In this embodiment, the third voltage level V3 is taken as an example of a low voltage level, and the fourth voltage level V4 is taken as an example of a high voltage level. In other words, every time the rotor rotates 120 degrees, the speed signal will have a pulse wave of one cycle. Every time the rotor rotates, the speed signal has a pulse wave of three cycles. The second control device 42 can be determined by the pulse wave cycle of the speed signal. Calculating the rotation speed of the rotor, thereby integrating the outputs of the three Hall sensors 384 into one, can effectively reduce the number of transmission lines in the transmission line group 50.

In an embodiment, the first controller 386 may also use the output of one of the Hall sensors 384 in the position signal as the rotational speed signal, and the second control device 42 uses the pulse output of a Hall sensor 384. The wave period calculates the speed of the rotor. In addition, if the second control device 42 does not need to obtain the rotational speed, the rotational speed signal line 507 may not be provided.

We can first define how the motor 32 should rotate in various rotation modes. For the convenience of description, take the rotation modes including a first rotation mode and a second rotation mode as an example. The first rotation mode is used to control the motor. 32 rotates in a first rotation direction D1, and the second rotation mode is used to control the motor 32 to rotate in a second rotation direction D2, the second rotation direction D2 is opposite to the first rotation direction D1.

After the definition of the rotation mode is completed, the frequency parameters in the second storage unit 424 are set in the second control device 42 to correspond to different rotation modes. For example, the frequency parameters include a first frequency parameter and a second frequency parameter. The first frequency parameter is used to generate a pulse width modulation signal with a pulse signal frequency of a first frequency, and the second frequency parameter is used to generate a pulse signal frequency with a pulse signal frequency. It is a pulse width modulation signal with a second frequency.

The control parameters in the first storage unit 388 are set in the first control device 38 to correspond to different pulse signal frequencies. For example, the control parameters include a first control parameter and a second control parameter. The first control parameter and the second control parameter correspond to the first frequency and the second frequency. The first control parameter is used to control the motor 32 along the first frequency. A rotation direction D1 rotates, and the second control parameter is used to control the motor 32 to rotate along the second rotation direction D2.

With the structure of the above-mentioned electric tool 2, the control method shown in FIG. 6 can be performed, which includes the following steps:

Step S11: Select one of the different rotation modes. In this embodiment, the user operates the operation interface 48 to select a corresponding rotation mode with the mode selector 484, the mode selector 484 outputs the corresponding selection signal to the second control device 42, and the second controller 422 transmits through the display 44 displays the information of the rotation mode. After the user presses the start switch 482, the following steps are performed.

Step S12: The second control device 42 generates a pulse width modulation signal according to the selected rotation mode, and transmits the pulse width modulation signal through the command transmission line 503.

In this embodiment, the second controller 422 selects a corresponding frequency parameter from the frequency parameters according to the selection signal, and generates the pulse width modulation signal with the corresponding pulse signal frequency according to the selected frequency parameter.

For example, the first frequency parameter is "21K", and the second frequency parameter is "10K". Please refer to FIG. 7. When the mode selector 484 selects the first rotation mode, the second controller 422 follows The selected first frequency parameter generates a pulse width modulation signal with a first frequency (21KHz). Please cooperate with FIG. 8, when the mode selector 484 selects the second rotation mode, the second controller 422 generates a pulse width modulation signal with a second frequency (10KHz) according to the selected second frequency parameter.

Step S13: The first control device 38 receives the pulse width modulation signal, analyzes the waveform of the pulse width modulation signal to obtain the pulse signal frequency, and controls the rotation mode according to a rotation mode corresponding to the obtained pulse signal frequency Motor 32.

In this embodiment, the first controller 386 analyzes the rising edge of a pulse in one cycle of the pulse width modulation signal and the rising edge of a pulse in the next cycle, and according to the rising edges of the two pulses The reciprocal of a time difference (that is, the first time difference T1 in FIG. 7 and FIG. 8) between, obtains a corresponding pulse signal frequency.

After acquiring the pulse signal frequency of the pulse width modulation signal, the first control device 38 selects the corresponding one from the control parameters in the first storage unit 388 according to the acquired pulse signal frequency to control the motor 32 Corresponding actions.

For example, the first controller 386 receives the pulse width modulation signal of FIG. 7 and obtains the pulse signal frequency as the first frequency (21KHz), and the first controller 386 is based on the first control parameter corresponding to the first frequency The commutation switching elements 382 are controlled to control the motor 32 to rotate along the first rotation direction D1. Similarly, when the first controller 386 receives the pulse width modulation signal of FIG. 8 and obtains the pulse signal frequency as the second frequency (10KHz), the first controller 386 controls according to the second control parameter corresponding to the second frequency The commutation switching elements 382 further control the motor 32 to rotate along the second rotation direction D2.

In the above, the different pulse signal frequencies of the pulse width modulation signal generated by the second control device 42 represent different rotation modes, and the pulse width modulation signal is transmitted through a command transmission line 503, which is analyzed by the first control device 38 The pulse width modulates the pulse signal frequency of the signal and controls the motor 32 in a corresponding rotation mode. In this way, the number of transmission lines in the transmission line group 50 can be reduced, and the wiring of the transmission line group 50 in the housing 30 is facilitated.

Figure 9 shows the power tool 3 of the second preferred embodiment of the present invention. It is based on the first embodiment. The difference is that the start switch 482 includes a speed selector 482a. When the user presses the start switch 482 , According to the depth of the pressing, the rotation speed selector 482a is also triggered to generate a corresponding rotation speed selection signal and transmit it to the second control device 42.

The second control device 42 generates a plurality of different rotation speed values from the rotation speed selection signal of the rotation speed selector 482a according to the depth of pressing the start switch 482. In one embodiment, the speed selector 482a can also be independent of the start switch 482, allowing the user to select the speed value and output the corresponding speed selection signal.

The second storage unit 424 of the second control device 42 stores a plurality of proportional value parameters, and the proportional value parameters respectively correspond to a plurality of different duty ratios. When the pulse width modulation signal is generated, it can be based on a proportional value Refer to change the duty cycle of the pulse width modulation signal.

The first storage unit 388 stores a plurality of rotation speed parameters, each of the rotation speed parameters is used by the first control device 38 to control the rotation speed of the motor 32 when the motor 32 rotates, and the rotation speed parameters correspond to different rotation speeds of the motor 32 respectively.

We can first define that the proportional value parameters of the second storage unit 424 correspond to the rotation speed values, and the proportional value parameters of the first storage unit 388 correspond to the duty ratios and correspond to the rotation speed values. The higher the duty cycle, the faster the rotation speed.

Fig. 10 shows the control method of the electric tool 3 according to the second preferred embodiment of the present invention, which has substantially the same steps as the first embodiment, except that:

Step S21: Select one of a plurality of different rotation modes. This step is the same as step S11 of the first embodiment. After the user presses the start switch 482, the following steps are performed.

Step S22: The second control device 42 generates a pulse width modulation signal according to the selected rotation mode, and adjusts the duty cycle of the pulse width modulation signal to one of a plurality of different ratios according to different rotation speed values, and The pulse width modulation signal is transmitted via the command transmission line 503.

In this embodiment, the second controller 422 selects a corresponding one of the frequency parameters from the frequency parameters according to the selection signal, and according to the depth at which the user presses the start switch 482, the rotation speed selection signal generates among the rotation speed values According to the generated rotation speed value, the second storage unit 424 selects a corresponding proportional value parameter. Then, the pulse width modulation signal with the corresponding pulse signal frequency is generated according to the selected frequency parameter, and the pulse width modulation signal with the corresponding duty ratio is generated according to the selected ratio parameter.

Taking the first frequency parameter "21K" as an example, one of the proportional value parameters is "23" as an example. Please refer to Fig. 11. When the mode selector 484 selects the first rotation mode, the second controller 422 selects The first frequency parameter generates a pulse width modulation signal with the first frequency (21KHz), and the corresponding proportional value parameter (such as "23") is selected according to the current rotation speed selection signal corresponding to the rotation speed value, and the corresponding duty cycle is generated as twenty three%. Please refer to Figure 12. One of the proportional value parameters is "60" as an example. When the depth of pressing the start switch is deeper and reaches the speed value of the corresponding proportional value parameter "60", the second controller corresponds to the current speed selection signal Select the corresponding proportional value parameter (such as "60") for the rotation speed value, and then change the duty cycle of the pulse width modulation signal to 60%.

Similarly, when the mode selector 484 selects the second rotation mode, the second controller 422 generates a pulse width modulation signal with a second frequency according to the selected second frequency parameter, and selects the rotation speed corresponding to the signal according to the current rotation speed Value selects the corresponding proportional value parameter and generates the duty cycle.

Step S23: The first control device 38 receives the pulse width modulation signal, analyzes the waveform of the pulse width modulation signal to obtain the pulse signal frequency and the duty ratio, and according to the obtained pulse signal frequency corresponding to The rotation mode controls the motor 32, and the rotation speed of the motor 32 is controlled according to the obtained duty ratio.

In conjunction with FIGS. 11 and 12, the first controller 386 analyzes the reciprocal of the first time difference T1 from the rising edge of a pulse in one cycle of the pulse width modulation signal to the rising edge of a pulse in the next cycle Obtain a corresponding pulse signal frequency. The first controller 386 analyzes a second time difference T2 between the rising edge and the falling edge of a pulse of one cycle of the pulse width modulation signal, and then according to the ratio of the second time difference T2 to the first time difference T1 Obtain the duty cycle.

After the first controller 386 obtains the pulse signal frequency and duty cycle of the pulse width modulation signal, the first controller 386 obtains the pulse signal frequency from the control parameters in the first storage unit 388 Select the corresponding one and select the corresponding one of the rotational speed parameters according to the current duty cycle, so as to control the action of the motor according to the selected rotation mode and control the motor 32 to generate the corresponding rotation mode according to the selected rotational speed parameter. Rotating speed.

For example, the first controller 386 receives the pulse width modulation signal of FIG. 11, and obtains the pulse signal frequency as the first frequency (21KHz) and the duty cycle is 23%. The first controller 386 is based on the first frequency The corresponding first control parameter and a rotation speed parameter corresponding to the duty ratio of 23% are used to control the commutation switching elements 382, thereby controlling the motor 32 to rotate along the first rotation direction D1 and have a corresponding rotation speed.

As shown in Fig. 13, during the rotation process, if the user changes the depth of pressing the start switch 482 to reach the speed value corresponding to the proportional value parameter "60", the second controller 422 corresponds to the current speed selection signal Select the proportional value parameter for the speed value of, and change the duty cycle of the pulse width modulation signal to 60%, then the first controller will be based on the first control parameter corresponding to the first frequency and the duty cycle will be 60% A corresponding rotation speed parameter controls the commutation switching elements 382, and then controls the motor 32 to rotate along the first rotation direction D1 and have a correspondingly higher rotation speed.

Similarly, if the pulse signal frequency of the pulse width modulation signal received by the first controller is the second frequency, the commutation is controlled according to the second control parameter and a rotation speed parameter corresponding to the current duty cycle The switch element 382 further controls the motor 32 to rotate along the second rotation direction D2 and at a corresponding rotation speed.

According to the above, the second embodiment of the present invention can also reduce the number of transmission lines in the transmission line group 50 by commanding the transmission line 503 to transmit the pulse width modulation signal, and can also use the duty cycle of the pulse width modulation signal to adjust the rotation speed at the same time. Use additional transmission lines to transmit speed life.

The rotation modes in the foregoing embodiments may further include other rotation modes, and are not limited to the first rotation mode and the second rotation mode.

The above are only the preferred and feasible embodiments of the present invention. Any equivalent changes made by applying the specification of the present invention and the scope of the patent application should be included in the patent scope of the present invention.

[Traditional] 1: power tools 10: Shell 102: Transmission Department 104: Handheld 12: Operation interface 14: Motor 16: upper circuit board 162: Commutation switching element 164: Hall sensor 18: Lower circuit board 182: Controller 20: Battery port 22: battery 24: Transmission line group [this invention] 2, 3: Power tools 30: shell 32: Motor 322: Hinge 34: Transmission parts 36: The first circuit board 38: The first control device 382: Commutation switching element 384: Hall sensor 386: first controller 388: first storage unit 40: second circuit board 42: Second control device 422: second controller 424: second storage unit 44: display 46: battery 48: Operation interface 482: Start switch 482a: Speed selector 484: Mode selector 50: Transmission line group 501: Power cord 502: Ground Wire 503: command transmission line 504: Brake signal cable 505: feedback signal line 506: Current signal line 507: Speed signal line D1: The first direction of rotation D2: The second direction of rotation S11~S13, S21~S23: steps V1: the first voltage level V2: second voltage level V3: third voltage level V4: The fourth voltage level

Figure 1 is a schematic diagram of a conventional electric tool. Figure 2 is a system block diagram of a conventional electric tool. Fig. 3 is a schematic diagram of the electric tool according to the first preferred embodiment of the present invention. Fig. 4 is a system block diagram of the above-mentioned preferred embodiment. FIG. 5 is a waveform diagram of the output and speed signals of the three Hall sensors in the above preferred embodiment. Fig. 6 is a flow chart of the control method of the electric tool in the above preferred embodiment. FIG. 7 is a waveform diagram of the pulse width modulation signal of the electric tool of the above-mentioned preferred embodiment. FIG. 8 is a waveform diagram of the pulse width modulation signal of the electric tool of the above-mentioned preferred embodiment. Fig. 9 is a schematic diagram of a power tool according to a second preferred embodiment of the present invention. Fig. 10 is a flow chart of the control method of the electric tool in the above preferred embodiment. FIG. 11 is a waveform diagram of the pulse width modulation signal of the electric tool of the above preferred embodiment. FIG. 12 is a waveform diagram of the pulse width modulation signal of the electric tool of the above-mentioned preferred embodiment. FIG. 13 is a waveform diagram of the pulse width modulation signal of the electric tool of the above preferred embodiment.

2: power tools

30: shell

32: Motor

322: Hinge

34: Transmission parts

36: The first circuit board

38: The first control device

40: second circuit board

42: Second control device

44: display

48: Operation interface

D1: The first direction of rotation

D2: The second direction of rotation

Claims (16)

An electric tool comprising: A motor A first circuit board is provided with a first control device, and the first control device is electrically connected to the motor; A second circuit board is electrically connected to the first circuit board through a transmission line group, wherein the transmission line group includes a command transmission line; the second circuit board is provided with a second control device, and the second control device is in a plurality of One of the different rotation modes generates a pulse width modulation signal, and transmits the pulse width modulation signal through the command transmission line, wherein the frequency of the pulse width modulation signal generated is a plurality of different pulse signal frequencies One of them, and the pulse signal frequencies correspond to the rotation modes respectively; The first control device receives the pulse width modulation signal, analyzes the pulse width modulation signal to obtain a corresponding pulse signal frequency, and controls the motor corresponding to a rotation mode corresponding to the obtained pulse signal frequency Action. The electric tool according to claim 1, wherein each cycle of the pulse width modulation signal generated by the second control device has a duty cycle, and the second control device adjusts the duty cycle according to a plurality of different rotation speed values. The duty ratio is one of a plurality of different ratios; the first control device analyzes the pulse width modulation signal to obtain the duty ratio, and further controls the rotation speed of the motor according to the obtained duty ratio. The electric tool according to claim 2, wherein the rotation modes include a first rotation mode and a second rotation mode, the pulse signal frequency corresponding to the first rotation mode is a first frequency, and the second rotation mode The corresponding pulse signal frequency is a second frequency; the second control device generates the corresponding pulse width modulation signal according to the first rotation mode or the second rotation mode, and adjusts the pulse width modulation signal according to a rotation speed value The ratio of the duty cycle of the variable signal; the first control device controls the motor according to the pulse signal frequency of the pulse width modulation signal, wherein, when the pulse signal frequency is the first frequency, the pulse width modulation signal The duty cycle is to control the motor to rotate in a first rotation direction according to the rotation speed value; when the pulse signal frequency is the second frequency, the duty cycle of the signal is modulated according to the pulse width, and the motor is controlled to rotate according to the rotation speed value. A second rotation direction rotates, and the second rotation direction is opposite to the first rotation direction. The electric tool according to claim 1, wherein the rotation modes include a first rotation mode and a second rotation mode, the pulse signal frequency corresponding to the first rotation mode is a first frequency, and the second rotation mode The corresponding pulse signal frequency is a second frequency; the second control device generates the corresponding pulse width modulation signal according to the first rotation mode or the second rotation mode; the first control device modulates according to the pulse width The pulse signal frequency of the signal controls the motor, wherein when the pulse signal frequency is a first frequency, the motor is controlled to rotate in a first rotation direction; when the pulse signal frequency is a second frequency, the motor is controlled to move along a first rotation direction Two rotation directions rotate, and the second rotation direction is opposite to the first rotation direction. The electric tool according to claim 1, wherein the second control device has a second storage unit, the second storage unit stores a plurality of frequency parameters, and the frequency parameters correspond to the pulse signal frequencies and the rotations respectively mode; The first control device has a first storage unit, and the first storage unit stores a plurality of control parameters, the control parameters respectively corresponding to pulse signal frequencies and corresponding to rotation modes; The second control device selects the corresponding frequency parameter according to one of the rotation modes, and generates the pulse width modulation signal with the corresponding pulse signal frequency according to the selected frequency parameter; The first control device selects a corresponding control parameter according to an acquired pulse signal frequency, and controls the corresponding action of the motor according to the selected control parameter. The electric tool according to claim 5, wherein the second storage unit stores a plurality of proportional value parameters, and the proportional value parameters respectively correspond to a plurality of different duty ratios and correspond to a plurality of different rotational speed values; The first storage unit stores a plurality of rotational speed parameters, and the rotational speed parameters correspond to duty ratios and rotational speed values; The second control device selects a corresponding proportional value parameter according to a rotation speed value, and generates the pulse width modulation signal with a corresponding duty cycle according to the selected proportional value parameter; The first control device analyzes the pulse width modulation signal to obtain a duty ratio, selects a corresponding rotation speed parameter according to the obtained duty ratio, and controls the motor to generate a corresponding rotation speed according to the selected rotation speed parameter. The electric tool according to claim 2, wherein the first control device analyzes the rising edge of a pulse wave in one cycle of the pulse width modulation signal and the rising edge of a pulse wave in the next cycle according to two The reciprocal of a first time difference between the rising edges of the pulse wave obtains a corresponding pulse signal frequency; wherein the first control device analyzes the pulse width modulation signal from the rising edge to the falling edge of a pulse wave in one cycle A second time difference between the two, and the duty cycle is obtained according to the ratio of the second time difference to the first time difference. The electric tool according to claim 1, wherein the first control device analyzes the rising edge of a pulse wave in one cycle of the pulse width modulation signal and the rising edge of a pulse wave in the next cycle according to two The reciprocal of the time difference between the rising edges of the pulse wave obtains a corresponding pulse signal frequency. A control method of an electric tool, wherein the electric tool comprises a motor, a first circuit board and a second circuit board, the first circuit board is provided with a first control device, wherein the first control device is electrically connected to the Motor; the second circuit board is electrically connected to the first circuit board through a transmission line set, wherein the transmission line set includes a command transmission line; the second circuit board is provided with a second control device; the control method includes the following steps: Choose one of a plurality of different rotation modes; The second control device generates a pulse width modulation signal according to the selected rotation mode, and transmits the pulse width modulation signal through the command transmission line, wherein the generated pulse width modulation signal has a plurality of different frequencies One of the pulse signal frequencies, and the pulse signal frequencies correspond to rotation modes respectively; The first control device receives the pulse width modulation signal, analyzes the pulse width modulation signal to obtain a corresponding pulse signal frequency, and controls the motor corresponding to a rotation mode corresponding to the obtained pulse signal frequency Action. The control method of an electric tool according to claim 9, wherein each cycle of the pulse width modulation signal generated by the second control device has a duty cycle, and the second control device depends on a plurality of different rotation speed values The duty ratio is adjusted to one of a plurality of different ratios; the first control device analyzes the pulse width modulation signal to obtain the duty ratio, and further controls the motor to change the rotation speed according to the obtained duty ratio. The control method of an electric tool according to claim 10, wherein the rotation modes include a first rotation mode and a second rotation mode; the second control device is the first rotation mode or the second rotation mode according to the selected rotation mode The second rotation mode generates the corresponding pulse width modulation signal, and adjusts the duty cycle ratio of the pulse width modulation signal according to a rotation speed value, wherein the pulse signal frequency corresponding to the first rotation mode is a first A frequency, the pulse signal frequency corresponding to the second rotation mode is a second frequency; the first control device controls the motor according to the pulse signal frequency of the pulse width modulation signal, wherein, when the pulse signal frequency is the first At the frequency, the duty ratio of the signal is modulated according to the pulse width, and the motor is controlled to rotate in a first rotation direction at the speed value; when the pulse signal frequency is the second frequency, the duty ratio of the signal is modulated according to the pulse width The idle ratio controls the motor to rotate in a second rotation direction according to the rotation speed value, and the second rotation direction is opposite to the first rotation direction. The control method of an electric tool according to claim 9, wherein the rotation modes include a first rotation mode and a second rotation mode; the second control device is the first rotation mode or the second rotation mode according to the selected rotation mode The second rotation mode generates the corresponding pulse width modulation signal, wherein the pulse signal frequency corresponding to the first rotation mode is a first frequency, and the pulse signal frequency corresponding to the second rotation mode is a second frequency; The first control device controls the motor according to the pulse signal frequency of the pulse width modulation signal, wherein when the pulse signal frequency is the first frequency, the motor is controlled to rotate in a first rotation direction according to the rotation speed; When the pulse signal frequency is the second frequency, the motor is controlled to rotate in a second rotation direction according to the rotation speed value, and the second rotation direction is opposite to the first rotation direction. The control method of an electric tool according to claim 9, wherein the step of generating the pulse width modulation signal by the second control device includes: According to the selected rotation mode, a corresponding one is selected from a plurality of frequency parameters, wherein the frequency parameters correspond to the pulse signal frequencies and correspond to the rotation modes; and Generate the pulse width modulation signal with the corresponding pulse signal frequency according to the selected frequency parameter; Wherein, the step of controlling the motor by the first control device according to a rotation mode corresponding to the acquired pulse signal frequency includes: According to an acquired pulse signal frequency, the corresponding one is selected from a plurality of control parameters, wherein the control parameters correspond to the pulse signal frequencies and the rotation modes respectively; and Control the corresponding action of the motor according to the selected control parameter. The control method of an electric tool according to claim 13, wherein the step of generating the pulse width modulation signal by the second control device further includes: According to one of the plurality of speed values, the corresponding one is selected from the plurality of proportional value parameters, wherein the proportional value parameters correspond to a plurality of different duty ratios; Generate the pulse width modulation signal with the corresponding duty cycle according to the selected proportional value parameter; Wherein, the step of controlling the motor by the first control device according to a rotation mode corresponding to the acquired pulse signal frequency further includes: Analyze the pulse width modulation signal to obtain the duty cycle; Select the corresponding one from a plurality of speed parameters according to the obtained duty ratio; According to the selected speed parameter, the motor is controlled to produce the corresponding speed when it is actuated. The control method of an electric tool according to claim 10, wherein the first control device analyzes the rising edge of a pulse wave in one cycle of the pulse width modulation signal and the rising edge of a pulse wave in the next cycle, and A corresponding pulse signal frequency is obtained according to the reciprocal of a first time difference between the rising edges of the two pulses; wherein the first control device analyzes the rising edge of a pulse of one cycle of the pulse width modulation signal to A second time difference between the falling edges, and the duty cycle is obtained according to the ratio of the second time difference to the first time difference. The control method of an electric tool according to claim 9, wherein the first control device analyzes the rising edge of a pulse wave in one cycle of the pulse width modulation signal and the rising edge of a pulse wave in the next cycle, and According to the reciprocal of the time difference between the rising edges of the two pulse waves, a corresponding pulse signal frequency is obtained.

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