CN213342062U - Electric tool - Google Patents
Electric tool Download PDFInfo
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- CN213342062U CN213342062U CN202022197037.1U CN202022197037U CN213342062U CN 213342062 U CN213342062 U CN 213342062U CN 202022197037 U CN202022197037 U CN 202022197037U CN 213342062 U CN213342062 U CN 213342062U
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- control module
- braking
- power tool
- motor
- switching tubes
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Abstract
The utility model discloses an electric tool. The method comprises the following steps: the control module controls at least two upper switching tubes or at least two lower switching tubes of the inverter circuit to be conducted at a first duty ratio smaller than one hundred percent for braking when detecting a turn-off signal of the operating switch, and the control module controls at least two upper switching tubes or at least two lower switching tubes of the inverter circuit to be conducted at one hundred percent for braking when detecting that the voltage detected by the peak voltage detection module is higher than an internally stored preset value. The utility model discloses a through controlling the braking, can realize slow braking, reduce the shut down noise, can prevent simultaneously that peak voltage from puncturing the switch tube, the instrument is longe-lived.
Description
[ technical field ] A method for producing a semiconductor device
The utility model relates to an electric tool, in particular to electric tool's control field.
[ background of the invention ]
The braking mode that brushless electric tool adopted usually has the short circuit braking, switch on inverter circuit's last switch tube or lower switch tube, make motor stator winding short circuit, the kinetic energy consumption of motor is on the stator winding of short circuit, brushless motor's kinetic energy is released fast, but the mode of direct brake is adopted to electric tool on the market, make brushless motor instantaneously produce very big braking torque, the reaction force that can lead to the instrument is big, consequently when the instrument shuts down, slow brake is carried out to it, switch tube or lower switch tube in the repeated break-make promptly, can play the effect of slow brake, the noise that reduces reaction force and instrument also consequently can be reduced, but the switch tube of relapse break-make, can make the winding both ends produce very high peak voltage, break down the switch tube easily, influence the instrument life-span.
In chinese utility model application No. CN210139370U, published in 2020, 03, 13, it is disclosed that when the switch is turned off, the control section continues to turn on at least one of the lower switching elements or at least one of the upper switching elements to perform the first braking control (duty ratio 100%), and when the rotational speed reaches a predetermined rotational speed or less, controls the switching elements to be repeatedly turned on and off to perform the second braking control (duty ratio 40%), until the motor stops, the initial braking force is large, the peak voltage is not controlled, the switching elements are easily broken down, and the tool life is short.
Therefore, there is a need for a power tool capable of suppressing the spike voltage to solve the above problems.
[ Utility model ] content
To the not enough of prior art, the utility model aims to provide an electric tool of increase of service life.
The utility model provides a prior art problem can adopt following technical scheme: the method comprises the following steps: the control circuit board comprises a control module, an inverter circuit connected between the control module and the motor and a spike voltage detection module connected between the power supply, the inverter circuit comprises a plurality of bridge arms, the bridge arms respectively comprise an upper switch tube and a lower switch tube, the operating switch sends a switching signal to the control module, the control module stores a preset value, when the control module detects a turn-off signal of the operating switch, the control module controls at least two upper switch tubes or at least two lower switch tubes of the inverter circuit to be conducted at a first duty ratio smaller than one hundred percent for braking, and when the voltage detected by the spike voltage detection module is higher than the preset value, the control module controls at least two upper switch tubes or at least two lower switch tubes to be conducted at a second duty ratio of one hundred percent, and (5) braking.
The further improvement scheme is as follows: the peak voltage detection module comprises a voltage division circuit connected between the power supplies, the voltage division circuit comprises a first resistor and a second resistor which are connected in series, the connection position of the first resistor and the second resistor is connected with the control module, and the control module detects the peak voltage.
The further improvement scheme is as follows: the inverter circuit comprises three bridge arms, each bridge arm comprises an upper switching tube and a lower switching tube, and the control module controls the three lower switching tubes to be conducted during braking.
The further improvement scheme is as follows: a zero-crossing detection circuit is connected between the motor and the control module, the control module detects the rotating speed of the motor according to the zero-crossing detection circuit, when the operation switch is switched off, the motor has a stop rotating speed, and the first duty ratio is in positive correlation with the stop rotating speed.
The further improvement scheme is as follows: the first duty cycle is fixed.
The further improvement scheme is as follows: the first duty cycle is 50%.
The further improvement scheme is as follows: the first duty cycle is gradually increased.
The further improvement scheme is as follows: the switch tube is an MOS tube.
The further improvement scheme is as follows: the motor is a brushless motor.
Compared with the prior art, the utility model discloses following beneficial effect has: when the control module detects a turn-off signal of the operating switch, the control module controls at least two upper switching tubes or at least two lower switching tubes of the inverter circuit to be switched on at a first duty ratio smaller than one hundred percent for braking, and when the voltage detected by the peak voltage detection module connected between the power supplies is higher than a preset value stored in the controller, the control module controls the at least two upper switching tubes or the at least two lower switching tubes to be switched on at a second duty ratio of one hundred percent for braking. Through changing brake signal, make the instrument slowly brake, reduce the shut down noise, can prevent simultaneously that spike voltage from puncturing the switch tube, the instrument is longe-lived.
[ description of the drawings ]
The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings:
fig. 1 is an overall structural view of the electric power tool of the present invention;
fig. 2 is a circuit diagram of the electric power tool of the present invention;
fig. 3 is a timing chart of the brake control and the peak voltage according to the first embodiment of the present invention;
fig. 4 is a timing chart of brake control and peak voltage according to the second embodiment of the present invention.
The meaning of the reference symbols in the figures:
1. casing 2, battery package 3, operating switch 4, motor 5, control module 6, inverter circuit 7, peak voltage detection module 8, zero cross detection circuit
[ detailed description ] embodiments
The present invention will be described in further detail with reference to the accompanying drawings and embodiments.
Referring to fig. 1 and 2, for the purpose of the present invention, an electric tool includes a housing 1, a battery pack 2 connected to the housing 1, an operation switch 3 installed on the housing 1, a motor 4 installed in the housing 1, and a control circuit board, the battery pack 2 is used as a power supply to supply power to the electric tool, the control circuit board includes a control module 5, an inverter circuit 6 connected between the control module 5 and the motor 4, and a peak voltage detection module 7 connected between the power supplies, the inverter circuit 6 includes a plurality of bridge arms, the plurality of bridge arms respectively include an upper switch tube and a lower switch tube, the operation switch 3 is electrically connected to the control module 5, when the control module 5 receives an off signal of the operation switch 3, the control module controls at least two upper switch tubes or at least two lower switch tubes of the inverter circuit 6 to be turned on at a first duty ratio smaller than one hundred percent, and performing braking, wherein when the voltage detected by the spike voltage detection module 7 is higher than a preset value stored in the control module 5, the control module 5 controls at least two upper switching tubes or at least two lower switching tubes of the inverter circuit 6 to be switched on at a second duty ratio of one hundred percent, so as to perform braking.
Referring to fig. 2, which is a circuit diagram of the electric tool of the present invention, the inverter circuit 6 includes a first bridge arm, a second bridge arm, and a third bridge arm connected between the positive electrode and the negative electrode of the power supply, and the first bridge arm is composed of a first switch tube Q1 (also called an upper switch) and a fourth switch tube Q4 (also called a lower switch) connected in series; the second bridge arm consists of a second switching tube Q2 (also called an upper switch) and a fifth switching tube Q5 (also called a lower switch) which are connected in series; the third bridge arm is composed of a third switch tube Q3 (also called an upper switch) and a sixth switch tube Q6 (also called a lower switch) which are connected in series, and each upper switch tube and each lower switch tube are respectively connected with diodes D1-D6 in a reverse parallel mode; the motor 4 is a brushless motor, the brushless motor includes a first phase winding U, a second phase winding V, and a third phase winding W, each phase winding is connected end to end, and each phase winding has one end led out to connect a midpoint of the first bridge arm, a midpoint of the second bridge arm, and a midpoint of the third bridge arm, of course, the windings of the motor 4 may also be star-connected. Meanwhile, a zero-crossing detection circuit 8 is connected between the three-phase winding of the motor 4 and the control module 5, and the control module 5 detects the rotating speed of the motor 4 according to the zero-crossing detection circuit 8. The spike voltage detection module 7 comprises a voltage dividing circuit connected between the power supplies, the voltage dividing circuit comprises a first resistor R1 and a second resistor R2 which are connected in series, the connection position of the first resistor R1 and the second resistor R2 is connected to the control module 5, and the control module 5 detects spike voltage.
Referring to fig. 3, in order to show a timing chart of the braking control and the peak voltage according to the first embodiment of the present invention, when the operating switch 3 is turned off, the motor 4 has a stop rotation speed, when the operating switch 3 is turned off at t0, the control module 5 detects an off signal of the operating switch 3, first, the control module 5 turns off six switching tubes of the inverter circuit 6 and starts braking, the control module 5 stores therein duty ratios corresponding to different rotation speeds, the first duty ratio is positively correlated with the stop rotation speed, that is, the stop rotation speed is high, the first duty ratio is high, the stop rotation speed is low, the first duty ratio is low, the control module 5 controls three lower switching tubes Q4, Q5, and Q6 to be turned on at a first duty ratio smaller than one hundred percent, and the lower switching tubes Q4, Q5, and Q6 can realize slow braking of the motor 4 through repeated on-off and on of the first duty ratio, the first duty ratio of the present embodiment is fixed to 50%. Since the lower switching tubes Q4, Q5, and Q6 are repeatedly turned on and off, and the current of the motor winding cannot suddenly change, when the lower switching tubes Q4, Q5, and Q6 are turned off, a high induced electromotive force is formed at both ends of the motor winding, which easily causes the breakdown of the switching tubes, so a preset value U1 is further stored in the control module 5, the control module 5 compares the voltage value of the second resistor R2 with the preset value U1, the voltage value is in direct proportion to the induced electromotive force at both ends of the motor winding, the induced electromotive force is high, the voltage value is high, when the voltage U2 reaches the preset value U1 at time t1, the control module 5 controls the three lower switching tubes Q4, Q5, and Q6 to brake at a duty ratio of 100%, at this time, the three-phase winding of the motor 4 consumes energy through a short-circuit formed by the three lower switching tubes Q4, Q5, and Q6, therefore, the quick braking is realized, and meanwhile, the voltage at two ends of the winding is pulled down, so that the switch tube can be prevented from being broken down. In this embodiment, since the withstand voltage of the switching tube is 40V, the induced electromotive force is set to 35V, that is, the corresponding preset value U1 is set to 27V. Certainly, two or three of the upper switch tubes can be conducted to brake or two of the lower switch tubes can be conducted to brake during braking, the control can realize slow braking, reduce tool noise, prevent spike voltage from puncturing the switch tubes and prolong the service life of the tool.
As shown in fig. 4, in order to provide a timing chart of braking control and spike voltage according to the second embodiment of the present invention, when the operating switch 3 is turned off at t0, the control module 5 turns off six switching tubes of the inverter circuit 6 and starts braking, the first duty ratio is gradually increased, the control module 5 detects the rotation speed of the motor to maintain the upper switching tube turned off and repeatedly turns on and off the three lower switching tubes Q4, Q5 and Q6, the motor 4 starts slow braking, of course, the first duty ratio is gradually decreased, when the time t1, the voltage detected by the spike voltage detecting module 7 reaches the preset value U1, the control module 5 controls the three lower switching tubes Q4, Q5 and Q6 to brake at a duty ratio of 100%, so as to achieve fast braking, and the control can achieve slow braking, reduce tool noise, and prevent spike voltage from breaking through the switching tubes, the service life of the tool is prolonged.
The utility model discloses a when control module 5 detected operating switch 3's turn-off signal, switching tube or at least two lower switching tubes switched on with being less than hundred percent's first duty cycle on two at least of control inverter circuit 6, brakies, when the voltage of connecting the peak voltage detection module 7 detection between the power is higher than the default of the inside storage of controller, control module 5 controls switching tube or at least two lower switching tubes switched on with hundred percent's second duty cycle on two at least, brakies. Through changing brake signal, make the instrument slowly brake, reduce the shut down noise, can prevent simultaneously that spike voltage from puncturing the switch tube, the instrument is longe-lived.
The present invention is not limited to the above-described embodiments. It will be readily appreciated by those skilled in the art that many other alternatives to the power tool may be made without departing from the spirit and scope of the invention. The protection scope of the present invention is subject to the content of the claims.
Claims (9)
1. A power tool, comprising: the control circuit board comprises a control module, an inverter circuit connected between the control module and the motor and a peak voltage detection module connected between the power supply, the inverter circuit comprises a plurality of bridge arms, the bridge arms respectively comprise an upper switch tube and a lower switch tube, and the operation switch sends a switching signal to the control module; the method is characterized in that: the control module stores a preset value, when the control module detects a turn-off signal of the operating switch, the control module controls at least two upper switching tubes or at least two lower switching tubes of the inverter circuit to be switched on at a first duty ratio smaller than one hundred percent for braking, and when the voltage detected by the peak voltage detection module is higher than the preset value, the control module controls at least two upper switching tubes or at least two lower switching tubes to be switched on at a second duty ratio of one hundred percent for braking.
2. The power tool of claim 1, wherein: the peak voltage detection module comprises a voltage division circuit connected between the power supplies, the voltage division circuit comprises a first resistor and a second resistor which are connected in series, the connection position of the first resistor and the second resistor is connected with the control module, and the control module detects the peak voltage.
3. The power tool of claim 2, wherein: the inverter circuit comprises three bridge arms, each bridge arm comprises an upper switching tube and a lower switching tube, and the control module controls the three lower switching tubes to be conducted during braking.
4. The power tool of claim 3, wherein: a zero-crossing detection circuit is connected between the motor and the control module, the control module detects the rotating speed of the motor according to the zero-crossing detection circuit, when the operation switch is switched off, the motor has a stop rotating speed, and the first duty ratio is in positive correlation with the stop rotating speed.
5. The power tool of claim 4, wherein: the first duty cycle is fixed.
6. The power tool of claim 5, wherein: the first duty cycle is 50%.
7. The power tool of claim 4, wherein: the first duty cycle is gradually increased.
8. The electric power tool according to claim 6 or 7, characterized in that: the switch tube is an MOS tube.
9. The electric power tool according to claim 6 or 7, characterized in that: the motor is a brushless motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022197037.1U CN213342062U (en) | 2020-09-29 | 2020-09-29 | Electric tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022197037.1U CN213342062U (en) | 2020-09-29 | 2020-09-29 | Electric tool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213342062U true CN213342062U (en) | 2021-06-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022197037.1U Active CN213342062U (en) | 2020-09-29 | 2020-09-29 | Electric tool |
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| Country | Link |
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| CN (1) | CN213342062U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024016536A1 (en) * | 2022-07-20 | 2024-01-25 | 江苏东成工具科技有限公司 | Braking system and method for brushless direct current motor |
| WO2024093817A1 (en) * | 2022-10-31 | 2024-05-10 | 江苏东成工具科技有限公司 | Braking control method and control device, and computer-readable medium |
-
2020
- 2020-09-29 CN CN202022197037.1U patent/CN213342062U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024016536A1 (en) * | 2022-07-20 | 2024-01-25 | 江苏东成工具科技有限公司 | Braking system and method for brushless direct current motor |
| WO2024093817A1 (en) * | 2022-10-31 | 2024-05-10 | 江苏东成工具科技有限公司 | Braking control method and control device, and computer-readable medium |
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