CN117134658A - Electric tool system and control method thereof - Google Patents
Electric tool system and control method thereof Download PDFInfo
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- CN117134658A CN117134658A CN202210551974.3A CN202210551974A CN117134658A CN 117134658 A CN117134658 A CN 117134658A CN 202210551974 A CN202210551974 A CN 202210551974A CN 117134658 A CN117134658 A CN 117134658A
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- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000001514 detection method Methods 0.000 claims abstract description 167
- 238000005070 sampling Methods 0.000 claims description 13
- 230000008569 process Effects 0.000 claims description 9
- 230000000875 corresponding effect Effects 0.000 description 10
- 230000001276 controlling effect Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 230000000737 periodic effect Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 230000004044 response Effects 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/08—Reluctance motors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/08—Reluctance motors
- H02P25/0805—Reluctance motors whereby the speed is regulated by measuring the motor speed and comparing it with a given physical value
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/08—Arrangements for controlling the speed or torque of a single motor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/28—Arrangements for controlling current
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Electric Motors In General (AREA)
Abstract
The present disclosure relates to a power tool system and a control method thereof. The system comprises: the motor is connected with the tool body; the driving circuit comprises a power switch tube, and the power switch tube receives a control signal and controls the motor to work; the first detection circuit is connected with the power switch tube and is used for detecting and obtaining a first detection value used for representing current information passing through the power switch tube; the second detection circuit is connected with the motor and used for detecting a second detection value used for representing the rotating speed of the motor; the speed controller is connected with the second detection circuit and is used for receiving a set reference speed value and determining a set value according to the reference speed value and a second detection value; and the current controller forms the control signal provided for the power switch tube according to the set value and the first detection value. Therefore, the running speed of the motor can be kept in a stable range, and the stable speed is realized.
Description
Technical Field
The present application relates to the field of power tools, and in particular, to a power tool system and a control method thereof.
Background
Along with the gradual wide application of electric tools, the current power output requirements on the electric tools are higher and higher, power switch tubes are often adopted in motor drive circuits of the electric tools, and the running state of a motor is controlled by controlling the on-off states of the power switch tubes. However, the running speed of the motor in the current electric tool often has an unstable condition, so that the use effect of the electric tool is affected. Therefore, how to keep the motor in the electric tool running at a steady speed is one of the problems that are urgently needed in the art.
Disclosure of Invention
In view of the above, it is desirable to provide a power tool system and a control method thereof.
According to a first aspect of embodiments of the present disclosure, there is provided a power tool system comprising:
the motor is connected with the tool body;
the driving circuit comprises a power switch tube, and the power switch tube receives a control signal and controls the motor to work;
the first detection circuit is connected with the power switch tube and is used for detecting and obtaining a first detection value used for representing current information passing through the power switch tube;
the second detection circuit is connected with the motor and used for detecting a second detection value used for representing the rotating speed of the motor;
the speed controller is connected with the second detection circuit and is used for receiving a set reference speed value and determining a set value according to the reference speed value and a second detection value;
and the current controller is respectively connected with the first detection circuit, the speed controller and the driving circuit, and forms the control signal provided for the power switch tube according to the set value and the first detection value.
In one embodiment, the control signal provided by the current controller has a plurality of control periods, and in the current control period, if the set value is higher than the first detection value, the current controller controls the power switch tube to be opened in the remaining time of the current time interval until the power switch tube is controlled to be closed at the beginning of the latter control period; and if the set value is lower than or equal to the first detection value in the current control period, the current controller controls the power switch tube to keep the current state in the remaining time of the current time interval until the current state is in the next control period.
In one embodiment, the set value is higher than the first detection value, and the current controller outputs a control signal for reducing the duty ratio to the driving circuit; the set value is lower than the first detection value, and the current controller outputs a control signal for improving the duty ratio to the driving circuit.
In one embodiment, the current controller includes a comparator, and the power tool system further includes a first preset value, the comparator being configured to compare the first detection value with a first preset value, the first preset value being greater than the set value;
the control signal provided by the current controller is provided with a plurality of control periods, the first detection value exceeds the first preset value in the current control period, and the current controller controls the power switch tube to be opened until the power switch tube is controlled to be closed at the beginning of the latter control period in the residual time of the current time interval.
In one embodiment, the current controller controls the motor to stop when the first detection value exceeds the first preset value for a preset period of time.
In one embodiment, the motor is a switched reluctance motor.
In one embodiment, the comparator includes a first input end, a second input end and an output end, the first input end is connected to the first detection circuit, the second input end is connected to the current controller, the current controller outputs the set value to the second input end, and the output end is connected to the current controller and is used for outputting the comparison result to the current controller.
In one embodiment, the comparator and the current controller are integrated in a main control chip, the main control chip comprises a plurality of pins, and the first detection circuit is connected with the pins corresponding to the comparator.
In one embodiment, a register is further connected between the current controller and the second input terminal.
According to a second aspect of the embodiments of the present disclosure, there is provided a control method of an electric tool system, wherein the electric tool system includes a motor, a driving circuit, a first detection circuit, a second detection circuit, a speed controller, and a current controller, the driving circuit includes a power switch tube, the power switch tube receives a control signal and controls the motor to operate, the first detection circuit is connected to the power switch tube, and is used for detecting a first detection value for obtaining current information representing passing through the power switch tube, the second detection circuit is connected to the motor, and is used for detecting a second detection value for representing a rotational speed of the motor, and the speed controller is connected to the second detection circuit, and is used for receiving a set reference speed value and determining a set value according to the reference speed value and the second detection value; the control method comprises the following steps:
receiving the first detection value of the first detection circuit and the set value of the speed controller;
and generating a control signal for the power switch tube according to the first detection value and the set value.
In one embodiment, the control signal includes a number of control cycles; the control method further includes:
in the current control period, if the set value is higher than the first detection value, the current controller controls the power switch tube to be opened in the remaining time of the current time interval until the power switch tube is controlled to be closed at the beginning of the next control period; and if the set value is lower than or equal to the first detection value in the current control period, the current controller controls the power switch tube to keep the current state in the remaining time of the current time interval until the current state is in the next control period.
According to the electric tool system and the control method thereof, the first detection value representing the current information of the power switch tube can be detected in real time through the detection circuit, the first detection value and the set value can be compared in real time through the comparator, the corresponding comparison result is output to the current controller, and the current controller forms a control signal for controlling the motor to work according to the set value and the first detection value, so that the speed value of the motor reaches the reference speed value, and the speed stabilization is realized.
Drawings
FIG. 1 is a schematic diagram of an embodiment of a power tool system according to an exemplary embodiment of the present application;
FIG. 2 is a schematic waveform diagram of a preset duty cycle and an actual duty cycle corresponding to a current limiting mode of a comparator according to the present application;
FIG. 3 is a schematic diagram of another embodiment of a power tool system according to an embodiment of the present application;
FIG. 4 is a schematic diagram of another embodiment of a power tool system according to an embodiment of the present application;
FIG. 5 is a block flow diagram of one implementation of a method of controlling a power tool system according to an embodiment of the present application;
fig. 6 is a flowchart of another implementation of a control method of an electric tool system according to an embodiment of the present application.
Reference numerals illustrate:
100. a motor; 200. a driving circuit; 300. a first detection circuit; 310. a detection element; 320. a signal processing element; 600. a second detection circuit; 800. a speed controller; 900. and a current controller.
Detailed Description
In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. The drawings illustrate preferred embodiments of the application. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The embodiment of the application provides an electric tool system, which is used for solving the problem of unstable motor rotation speed in the electric tool system.
Referring to fig. 1, the electric power tool system provided in the present embodiment includes a motor 100, a driving circuit 200, a first detection circuit 300, a second detection circuit 600, a speed controller 800, and a current controller 900.
Specifically, the motor 100 is connected to the tool body, and is used for driving the tool body to work; the driving circuit 200 comprises a power switch tube, and the power switch tube receives a control signal and controls the motor 100 to work; the first detection circuit 300 is connected with the power switch tube and is used for detecting and obtaining a first detection value used for representing current information passing through the power switch tube; a second detection circuit 600, connected to the motor 100, for detecting a second detection value indicative of the rotational speed of the motor; the speed controller 800 is connected to the second detection circuit, and is configured to receive a set reference speed value, and determine a set value according to the reference speed value and the second detection value. The reference speed value herein may include a target speed value that the motor is expected to maintain. For example, according to the actual work requirements, the motor rotation speed is required to be stabilized at 20000rpm (reference speed value), then this parameter is set in software. And a current controller 900 connected to the first detection circuit 300, the speed controller 800, and the driving circuit 200, wherein the current controller 900 forms the control signal provided to the power switching tube according to the set value and the first detection value. The tool body may include a tool body of an electric tool such as an angle grinder, an electric drill, an electric hammer, an electric wrench, or the like. The power switch tube can be a MOSFET, an IGBT and other power devices.
The motor 100 is connected to the tool body for providing a driving force to the tool body. Here, the motor may be a switched reluctance motor, a brushless motor, or the like. Taking an angle grinder as an example, a driving output shaft of the motor 100 is connected with a polishing disc of the angle grinder, and driving force is transmitted to the polishing disc through the driving output shaft to drive the polishing disc to rotate.
The driving circuit 200 is electrically connected to the motor 100 and is used for driving the motor 100. The driving circuit 200 may include a plurality of power switch tubes, where the gate end of each power switch tube is a control signal input end of the driving circuit 200, and is electrically connected to the output end of the current controller 900 in the main control chip, and the source drain electrode of each power switch tube is connected to the motor 100, and the power switch tube changes the on-off state of itself according to the control signal output by the current controller 900, so as to change the voltage condition on the motor 100, and further change the motor rotation speed, thereby controlling the working condition of the tool body.
The first detection circuit 300 is connected to the power switch tube and detects a first detection value representing current information passing through the power switch tube. Specifically, the first detection circuit 300 is connected to a circuit where the power switch tube is located, and the detected first detection value may represent current information passing through the power switch tube, and the first detection value may be a current value, a voltage value corresponding to the current value, or the like. In this embodiment, the first detection value is positively correlated with the current value flowing through the power switch tube, that is, the larger the first detection value is, the larger the current flowing through the power switch tube is.
In the above power tool system, the first detection circuit 300 may detect in real time a first detection value representing the current information passing through the power switch tube, the speed controller 800 is connected to the current controller 900, and the speed controller 800 is configured to receive a set reference speed value, where the reference speed value may include a target speed value that is desired to be maintained by the motor. The speed controller 800 determines a difference between the reference speed value and the actually detected second detection value as a variation amount, and superimposes the variation amount on the second detection value to obtain a set value. The further current controller 900 forms the control signal provided to the power switch tube according to the set value and the first detection value.
In one embodiment, the steady speed of the motor can be achieved by adjusting the closing/opening of the power switch tube. The control signal provided by the current controller 900 has a plurality of control periods, and in the current control period, if the set value is higher than the first detection value, the current controller controls the power switch tube to be opened in the remaining time of the current time interval until the power switch tube is controlled to be closed at the beginning of the subsequent control period. To reduce the supply of motor power, and to reduce the rotational speed to reach the reference speed value.
And if the set value is lower than or equal to the first detection value in the current control period, the current controller controls the power switch tube to keep the current state in the remaining time of the current time interval until the current state is in the next control period. To increase the supply of motor energy, and to increase the rotational speed to reach the reference speed value.
In this embodiment, the first detection value is consistent with the attribute of the set value. That is, if the first detection value is a current value, the set value may be directly the current value; if the first detection value is a voltage value, the set value is the voltage value.
Through the embodiment of the disclosure, the rotating speed of the motor can be always maintained above and below the reference speed value, and the speed stabilization is realized.
Specifically, a comparator or an AD software sample may be provided in the current controller 900, taking the comparator as an example, an input end of the comparator is connected to an output end of the first detection circuit 300, that is, the first detection circuit 300 may detect in real time to obtain a first detection value, and input the first detection value to the comparator, so long as the comparator is turned on, the comparator compares the first detection value with a set value, and outputs a corresponding comparison result, and the current controller 900 may control the power switch tube to be turned on or turned off according to the obtained comparison result, so as to implement control over the current, and further control the rotational speed of the motor, so that the rotational speed of the motor is stable. In addition, in the above process, the current controller 900 does not consume operation resources, ensures control without hysteresis, and improves the reliability of the electric tool system.
In this embodiment, the set value may be changed along with the change of the real-time rotation speed of the motor, for example, a reference speed value is preset according to the requirement, the real-time rotation speed difference is determined according to the difference between the fixed rotation speed value and the real-time rotation speed value of the motor, and then the real-time set value (may be a current value) is determined according to the real-time rotation speed difference, so as to compare the real-time set value with the real-time first detection value, so as to perform the subsequent control process.
For example, the first detection value is a current value a, the current set value is b, the upper limit value is h, the lower limit value is g, h is a positive number, and g is a negative number. During the operation of the electric tool, a is gradually increased, when the value of a-b exceeds h, the current value can be considered to exceed the current set value more, the motor rotating speed is too fast, and at the moment, the power switch tube can be controlled to be disconnected, so that the current provided by the bus to the motor is reduced, and the motor rotating speed is reduced; in the descending process, a is gradually reduced, when the value of a-b is reduced to g, the current value can be considered to be more than the current set value, the motor rotating speed is too slow, and at the moment, the power switch tube can be controlled to be closed, so that the current provided by the bus to the motor is increased, and the motor rotating speed is improved. The control process is repeatedly executed, so that the current value passing through the power switch tube can be stabilized within a certain range, and the running speed of the motor is controlled within a required range, thereby realizing the stable running of the motor.
In practical application, the larger the difference between the upper limit value and the lower limit value, the lower the control accuracy of the current, and conversely, the higher the control accuracy of the current. The set value can be determined according to actual demands, the larger the set value is, the larger the output torque of the motor is in the whole control process, and the damage to the power switch tube or the motor can be caused by the overlarge output torque, so that the set value can be reasonably set on the premise of meeting product working demands and avoiding damage to devices.
In one embodiment, the motor is a brushless motor, and the steady speed can be achieved by adjusting the duty cycle. The control signal includes a PWM signal. The set value is higher than the first detection value, and the current controller outputs a control signal for reducing the duty ratio to the driving circuit; the set value is lower than the first detection value, and the current controller outputs a control signal for improving the duty ratio to the driving circuit. If the set value is the same as the first detection value, the original control signal is kept to the driving circuit. In the embodiment of the disclosure, the duty ratio can be used as a control parameter of the current controller, and the effect of reducing the duty ratio is to gradually reduce the power, reduce the energy supply of the motor and reduce the rotating speed to reach the reference speed value. Increasing the duty cycle has the effect of increasing the power, increasing the power supply to the motor, and increasing the rotational speed to reach the reference speed value. In the embodiment of the application, the purpose of stabilizing the speed is realized by comparing the first detection value with the set value, and the first detection value can be compared with the first preset value to further realize current limitation and further improve the anti-blocking capability. Wherein the first preset value is greater than the set value. Specifically, a first preset value may be set, where the first preset value is a fixed value, and when it is determined that the first detection value exceeds the first preset value, the power switching tube may be controlled to be used for current limiting so as to improve the blocking capability.
In one embodiment, the current controller includes a comparator, and the power tool system further includes a first preset value, the comparator being configured to compare the first detection value with a first preset value, the first preset value being greater than the set value; the control signal provided by the current controller has a plurality of control periods. And in the current control period, the first detection value exceeds the first preset value, and in the remaining time of the current time interval, the current controller controls the power switch tube to be opened until the power switch tube is controlled to be closed at the beginning of the next control period. That is, if the current is too large in the current control period, the power switch tube keeps the off state in the rest time of the current control period, and the periodic control of the power switch tube is restored at the coming time of the next control period; or the power switch tube is kept in the off state in a plurality of subsequent control periods, for example, the power switch tube is kept in the off state in 2 subsequent control periods, when the 3 rd control period comes, the periodic control on the power switch tube is recovered, or the power switch tube is kept in the off state in 4 subsequent control periods, and when the 5 th control period comes, the periodic control on the power switch tube is recovered. In practical applications, the time interval may be set according to practical requirements, which is not listed here.
When the current is too high, the periodic control of the power switch tube is recovered after the power switch tube is disconnected for a period of time, so that the current can be ensured not to be too high again in a short time, and the periodic control of the power switch tube is prevented from being influenced by frequently controlling the disconnection of the power switch tube, thereby influencing the normal operation of the electric tool.
In one embodiment, the current controller may further determine that the first detection value exceeds the first preset value and lasts for a preset period of time, and if the preset period of time is continued, the current controller may stop supplying power to the motor, i.e. control the motor to stop. Wherein, judge the duration of presetting, help avoiding misjudgement, improve the accuracy of control. The preset time period may be set to 5 seconds, 6 seconds, 8 seconds, etc., preferably 5 seconds.
In this embodiment, by comparing the first detection value with the set value and the first preset value by the comparator and controlling the power switch tube by the current controller according to the comparison result, good steady speed control and current limiting can be implemented on the operation of the electric tool, and meanwhile, compared with the traditional software control mode, the hardware control mode adopted in this embodiment effectively reduces the processing time and resources consumed inside the current controller, and avoids the problems of larger current fluctuation, overlarge current and damage to the power switch tube and the motor caused by control lag.
In one embodiment, referring to fig. 4, the comparator 410 includes a first input terminal, a second input terminal and an output terminal, the first input terminal is connected to the first detection circuit 300, the second input terminal is connected to the current controller 900, the current controller 900 outputs a set value to the second input terminal, and the output terminal of the comparator 410 is connected to the current controller 900 for outputting a comparison result to the current controller 900.
That is, a first input terminal of the comparator is connected to an output terminal of the first detection circuit 300, receives a first detection value output by the first detection circuit 300, a second input terminal of the comparator is connected to an output terminal of the current controller 900, receives a set value output by the current controller 900, compares the first detection value and the set value inside the comparator, and outputs a comparison result to the current controller 900 through the output terminal.
Fig. 2 is a waveform diagram corresponding to current limiting implemented by the hardware control method in the present embodiment. Referring to fig. 2, each PWM control period includes alternating high-level signals and low-level signals (preset duty ratio), and during the high-level signals of the 2 nd PWM control period, the actual duty ratio is immediately set low at the moment when the current exceeds the limit value, and no response delay problem occurs. It can be seen that the response speed of the hardware current limiting scheme in this embodiment is faster.
Meanwhile, as can be seen from fig. 2, the current controller 900 switches the current high level signal to a low level, i.e. turns off the power switch tube, and keeps the low level state of the control signal in the remaining time of the 2 nd PWM control period until the 3 rd PWM control period arrives, and the current controller 900 resumes the switching control of the high and low level signal to the power switch tube. Similarly, the power switch tube is controlled in the following way.
In one embodiment, referring to fig. 4, a register 430 is further connected between the current controller 900 and the second input terminal, and the current controller 900 configures a first preset value in the register 430.
The current controller 900 may configure the first preset value in the register 430 in advance, and in practical application, the register 430 outputs the first preset value to the comparator to provide a comparison object, which is easy to implement.
In one embodiment, the comparator and the current controller are integrated in a main control chip, the main control chip includes a plurality of pins, and the first detection circuit 300 is connected to the pin corresponding to the comparator 410. The comparator 410 and the current controller 900 are integrated in the same main control chip, so that the integration level of the electric tool system is improved, signal transmission between the comparator 410 and the current controller 900 is facilitated, and the signal transmission efficiency is improved. The main control chip comprises a plurality of pins for external connection, wherein the output end of the comparator 410 is connected with the pins for external connection on the main control chip, namely, the output end of the comparator is led out so as to be connected with the output end of the detection circuit.
In one embodiment, when the comparator determines that the comparison result between the first detection value and the set value or the first preset value is a preset result, an interrupt signal is output to the current controller 900, and the current controller 900 controls the power switch to be turned on or off when receiving the interrupt signal, where the preset result includes any one or more of that the difference between the first detection value and the set value exceeds the upper limit value, that the difference between the first detection value and the set value exceeds the lower limit value, and that the first detection value exceeds the first preset value.
That is, when the current controller 900 receives the interrupt signal from the comparator during the process of controlling the driving circuit 200 according to the preset control signal, the current controller stops controlling the driving circuit 200 according to the original control signal, and directly outputs a signal for opening or closing the power switch in the driving circuit 200. That is, the current controller 900 does not need to perform internal operations, thereby saving internal resources and providing control efficiency.
Wherein the interrupt signal may comprise a high level signal. For example, when the comparison result is that the first detection value exceeds the first preset value, a high level signal is output to the current controller 900, and the current controller 900 controls the power switch to be turned off.
Of course, the comparator may output other types of interrupt signals, as long as the current controller 900 is able to close or open the power switch tube at the first time when receiving the signals.
In addition, in the actual control process, the comparator also compares the first detection value with a second preset value, and the controller can stop supplying power to the motor when the first detection value exceeds the second preset value. The second preset value is generally greater than the first preset value for short-circuit protection.
In one embodiment, referring to fig. 3, the first detection circuit 300 includes a detection element 310 and a signal processing element 320. The detection element 310 is connected in series between the power switch tube and the comparator, and samples in real time to obtain a first detection value; the signal processing element 320 is connected to the detecting element 310 and the comparator, respectively, and processes the first detection value and outputs the processed first detection value to the comparator. The first detection value is obtained by sampling the detection element 310 in real time, and the first detection value is processed by the signal processing element 320 and then output to the comparator, so that the comparator can directly compare and analyze the processed data.
The processing of the first detection value by the signal processing element 320 may include a de-interference processing to filter the interference signal output by the detection element 310, so as to improve the accuracy of the data input to the comparator.
In one embodiment, referring to fig. 4, the first detection circuit 300 includes a detection element 310 and a signal processing unit 320. The detection element 310 comprises a sampling resistor and the signal processing element 320 comprises an operational amplifier. That is, the current information is detected by connecting the sampling resistor in series to the output line of the power switching transistor, which is simple and low-cost. The first detection value can be amplified by a set multiple through the operational amplifier, so that interference signals are avoided.
In one embodiment, the first detection value may be a voltage value at two ends of the sampling resistor, and the set value and the first preset value may be voltage values, where the first preset value may be a product of a resistance value of the sampling resistor and a current limit value of the power switch tube.
When a sampling resistor is used as the current detecting element 310, the voltage value across the sampling resistor is obtained to characterize the current flowing through the sampling resistor (the ratio of the voltage value to the resistance value of the sampling resistor), that is, the current flowing through the power switch tube. The first preset value is the product of the current limit value of the power switch tube and the resistance value of the sampling resistor, and the comparator compares the product with the voltage values at two ends of the sampling resistor, namely, the comparison of the current passing through the power switch tube and the current limit value is equivalent. For example, when the voltage values at two ends of the sampling resistor exceed the first preset value, the current passing through the power switch tube is determined to exceed the current limit value, and then a corresponding comparison result is output, so that the current controller 900 performs current limiting, otherwise, the normal control of the current controller 900 on the driving circuit 200 is maintained.
In one embodiment, the power tool system further includes a power module for providing power to the driving circuit 200, and a rectifying module connected between the power module and the driving circuit for converting ac power to dc power.
In one embodiment, a control method of a power tool system is provided, which may be used to control the aforementioned power tool system. The electric tool system comprises a motor, a driving circuit, a detection circuit and a comparator, wherein the driving circuit comprises a power switch tube, and the power switch tube receives a control signal and controls the motor to work.
Referring to fig. 5, the control method of the electric tool system provided in the present embodiment includes:
step S410, receiving the first detection value of the first detection circuit and a set value determined by the speed controller according to a reference speed value and a second detection value;
and step S420, generating a control signal for the power switch tube according to the first detection value and the set value.
In one embodiment, the control signal has a number of control cycles; referring to fig. 6, a control method step S420 of the electric tool system provided in the present embodiment includes:
step S430, in the current control period, if the set value is higher than the first detection value, the current controller controls the power switch tube to be opened in the remaining time of the current time interval until the power switch tube is controlled to be closed at the beginning of the latter control period;
and step S440, if the set value is lower than or equal to the first detection value in the current control period, the current controller controls the power switch tube to keep the current state in the remaining time of the current time interval until the current state is in the next control period.
According to the control method of the electric tool system, the first detection value representing the current information of the power switch tube can be detected in real time through the detection circuit, the first detection value and the set value can be compared in real time through the comparator, the corresponding comparison result is output to the current controller, the current controller can control the power switch tube to be opened when the difference value between the first detection value and the set value exceeds the upper limit value, and the power switch tube to be closed when the difference value between the first detection value and the set value exceeds the lower limit value, so that the running speed of the motor can be kept in a stable range, and the stable speed is realized. Compared with software current limiting, the control method does not need to set an internal program to calculate and compare the data detected by the detection circuit, so that the processing time and the resources consumed by the current controller are effectively reduced.
The control method of the electric tool system provided in this embodiment belongs to the same inventive concept as the electric tool system provided in the foregoing embodiment, and the specific content of the control method may be referred to the description of the corresponding embodiment of the electric tool system, which is not repeated here.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (11)
1. A power tool system, the power tool system comprising:
the motor is connected with the tool body;
the driving circuit comprises a power switch tube, and the power switch tube receives a control signal and controls the motor to work;
the first detection circuit is connected with the power switch tube and is used for detecting and obtaining a first detection value used for representing current information passing through the power switch tube;
the second detection circuit is connected with the motor and used for detecting a second detection value used for representing the rotating speed of the motor;
the speed controller is connected with the second detection circuit and is used for receiving a set reference speed value and determining a set value according to the reference speed value and a second detection value;
and the current controller is respectively connected with the first detection circuit, the speed controller and the driving circuit, and forms the control signal provided for the power switch tube according to the set value and the first detection value.
2. The power tool system of claim 1, wherein the control signal provided by the current controller has a plurality of control cycles, and the current controller controls the power switch to be turned off until the power switch is controlled to be turned on at the beginning of a subsequent control cycle during the remaining time of the current time interval if the set value is higher than the first detection value during the current control cycle; and if the set value is lower than or equal to the first detection value in the current control period, the current controller controls the power switch tube to keep the current state in the remaining time of the current time interval until the current state is in the next control period.
3. The power tool system of claim 1, wherein the set point is higher than the first detection value, and the current controller outputs a control signal to decrease the duty cycle to the drive circuit; the set value is lower than the first detection value, and the current controller outputs a control signal for improving the duty ratio to the driving circuit.
4. The power tool system of claim 1, wherein the current controller includes a comparator, the power tool system further comprising a first preset value, the comparator for comparing the first detection value with a first preset value, the first preset value being greater than the set value;
the control signal provided by the current controller is provided with a plurality of control periods, the first detection value exceeds the first preset value in the current control period, and the current controller controls the power switch tube to be opened until the power switch tube is controlled to be closed at the beginning of the latter control period in the residual time of the current time interval.
5. The power tool system of claim 4, wherein the current controller controls the motor to stop when the first detection value exceeds the first preset value for a preset period of time.
6. The power tool system of claim 4, wherein the comparator includes a first input terminal, a second input terminal, and an output terminal, the first input terminal being connected to the first detection circuit, the second input terminal being connected to the current controller, the current controller outputting the set value to the second input terminal, the output terminal being connected to the current controller for outputting the comparison result to the controller.
7. The power tool system of claim 6, wherein the comparator and the current controller are integrated in a main control chip, the main control chip comprises a plurality of pins, and the first detection circuit is connected to the pins corresponding to the comparator.
8. The power tool system of claim 6, wherein a register is further connected between the current controller and the second input.
9. The power tool system of claim 1, wherein the first detection circuit comprises:
the detection element is connected in series between the power switch tube and the current controller and is used for sampling in real time to obtain the first detection value;
and the signal processing element is respectively connected with the detection element and the current controller, processes the first detection value and outputs the processed first detection value to the current controller.
10. The control method of the electric tool system is characterized in that the electric tool system comprises a motor, a driving circuit, a first detection circuit, a second detection circuit, a speed controller and a current controller, wherein the driving circuit comprises a power switch tube, the power switch tube receives a control signal and controls the motor to work, the first detection circuit is connected with the power switch tube and is used for detecting and obtaining a first detection value used for representing current information passing through the power switch tube, the second detection circuit is connected with the motor and is used for detecting a second detection value used for representing the rotating speed of the motor, and the speed controller is connected with the second detection circuit and is used for receiving a set reference speed value and determining a set value according to the reference speed value and the second detection value; the control method comprises the following steps:
receiving the first detection value of the first detection circuit and the set value of the speed controller;
and generating a control signal for the power switch tube according to the first detection value and the set value.
11. The method of claim 10, wherein the control signal comprises a number of control cycles; the control method further includes:
in the current control period, if the set value is higher than the first detection value, the current controller controls the power switch tube to be opened in the remaining time of the current time interval until the power switch tube is controlled to be closed at the beginning of the next control period; and if the set value is lower than or equal to the first detection value in the current control period, the current controller controls the power switch tube to keep the current state in the remaining time of the current time interval until the current state is in the next control period.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210551974.3A CN117134658A (en) | 2022-05-20 | 2022-05-20 | Electric tool system and control method thereof |
| PCT/CN2023/094742 WO2023222026A1 (en) | 2022-05-20 | 2023-05-17 | Power tool system and control method therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210551974.3A CN117134658A (en) | 2022-05-20 | 2022-05-20 | Electric tool system and control method thereof |
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| CN117134658A true CN117134658A (en) | 2023-11-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210551974.3A Pending CN117134658A (en) | 2022-05-20 | 2022-05-20 | Electric tool system and control method thereof |
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| CN (1) | CN117134658A (en) |
| WO (1) | WO2023222026A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102710190A (en) * | 2012-06-11 | 2012-10-03 | 成都伟瓦节能科技有限公司 | Working speed control method for switched reluctance motor |
| CN103312245B (en) * | 2013-06-24 | 2016-08-10 | 珠海格力电器股份有限公司 | Motor controller and motor control method |
| TWM576750U (en) * | 2017-07-25 | 2019-04-11 | 美商米沃奇電子工具公司 | Electrical composition, electric device system, battery pack, electric motor, motor assembly and electric motor assembly |
| CN110718995B (en) * | 2019-10-25 | 2021-04-06 | 华中科技大学 | Current detection method and detection system for multi-phase switched reluctance motor |
| CN111917355B (en) * | 2020-07-30 | 2022-04-05 | 南京凌鸥创芯电子有限公司 | Motor speed regulation system and method for massage application |
| EP4311101A4 (en) * | 2021-05-12 | 2024-09-18 | Nanjing Chervon Ind Co Ltd | Power tool and control method therefor |
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