CN110752801A - Grass trimmer control method and device and grass trimmer - Google Patents
Grass trimmer control method and device and grass trimmer Download PDFInfo
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- CN110752801A CN110752801A CN201910997934.XA CN201910997934A CN110752801A CN 110752801 A CN110752801 A CN 110752801A CN 201910997934 A CN201910997934 A CN 201910997934A CN 110752801 A CN110752801 A CN 110752801A
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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
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
- H02P6/17—Circuit arrangements for detecting position and for generating speed information
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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
- H02P6/20—Arrangements for starting
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Abstract
The invention discloses a grass trimmer control method, a grass trimmer control device and a grass trimmer, wherein the grass trimmer comprises a storage battery, a controller and a brushless direct current motor, the controller comprises a motor engine ME, an 8051 kernel, a motor position detector and a voltage acquisition circuit, the motor position detector is used for detecting the position of a motor rotor of the grass trimmer, the voltage acquisition circuit is used for acquiring the voltage value of the storage battery of the grass trimmer and the voltage value of a speed regulation signal of the brushless direct current motor, and the grass trimmer control method comprises the following steps: acquiring a voltage value of a storage battery and a voltage value of a speed regulation signal acquired by a voltage acquisition circuit; when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold value, controlling the brushless direct current motor to start; and acquiring the rotor position of the brushless direct current motor detected by the motor position detector, and controlling the motor engine ME to operate in a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor. The technical scheme of the invention improves the operation reliability of the grass trimmer.
Description
Technical Field
The invention relates to the technical field of motor control, in particular to a grass mower control method and device and a grass mower.
Background
A common grass mower uses a direct-current brush motor, the direct-current brush motor realizes the mutual conversion between direct-current quantity and alternating-current quantity in a winding by adopting sliding contact of an electric brush and a commutator, and the problems of spark generation, wireless interference, operation maintenance period, operation environment guarantee and the like are difficult to avoid. With the development of electronic technology, a brushless motor is produced, which replaces mechanical commutation with electronic commutation, avoids the sliding contact between the brush and the commutator, and has better operation reliability and speed regulation performance than the traditional direct current brush motor.
However, the traditional brushless motor driving algorithm is written by pure software, and for adopting a non-inductive FOC control mode, if a high-speed motor is to be driven, the main frequency of the MCU is required to be very high, and an external operational amplifier, a comparator and the like are required to be hung, so that the area of a control panel is increased, and the reliability is reduced; for the non-inductive square wave control mode, 60-degree commutation reference time, shielding follow current time, time from detecting position signals to commutation time, software control three-phase six-path PWM output and the like need to be acquired through a timer and interrupt matching mode, the software is complex in time sequence and long in processing time, external operational amplifiers, comparators and the like are needed, the number of components on the control panel is large, the area of the control panel is increased, and reliability is reduced.
Disclosure of Invention
The invention mainly aims to provide a grass trimmer control method and device and a grass trimmer, and aims to improve the operation reliability of the grass trimmer.
In order to achieve the above object, the present invention provides a control method of a grass trimmer, which comprises a storage battery, a controller and a brushless dc motor, wherein the controller comprises a motor engine ME, an 8051 core, a motor position detector for detecting the position of a motor rotor of the grass trimmer, and a voltage acquisition circuit for acquiring the voltage value of the storage battery of the grass trimmer and the voltage value of a speed regulation signal of the brushless dc motor, and the control method of the grass trimmer comprises:
acquiring a voltage value of a storage battery of the grass trimmer and a voltage value of a speed regulation signal of the brushless direct current motor, which are acquired by the voltage acquisition circuit;
when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold value, controlling the brushless direct current motor to start;
and acquiring the rotor position of the brushless direct current motor detected by the motor position detector, and controlling the motor engine ME to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor.
Optionally, when the voltage value of the speed regulation signal is greater than or equal to a preset startup threshold and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold, the step of controlling the brushless dc motor to start further includes:
and acquiring the initial position of the rotor of the brushless direct current motor detected by the motor position detector.
Optionally, the lawn mower further includes a status indicator light, and when the voltage value of the speed regulation signal is greater than or equal to a preset startup threshold value and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold value, the step of controlling the brushless dc motor to start further includes:
and controlling the state indicator lamp to light green.
Optionally, after the step of obtaining the voltage value of the storage battery of the lawn mower and the voltage value of the speed regulation signal of the brushless dc motor, which are collected by the voltage collecting circuit, is performed, the method for controlling the lawn mower further includes:
when the voltage value of the speed regulating signal is smaller than a preset starting threshold value, controlling the state indicator lamp to light a yellow lamp;
and when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is less than an undervoltage protection threshold value, controlling the state indicator lamp to light a red lamp.
Optionally, the step of obtaining the rotor position of the brushless dc motor detected by the motor position detector, and controlling the motor engine ME to operate in the non-inductive FOC control mode or the non-inductive square wave control mode according to the rotor position of the brushless dc motor further includes:
when the brushless direct current motor rotor is detected to be in a static state, acquiring the position of the brushless direct current motor rotor detected by the motor position detector;
and controlling a motor engine ME to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor.
Optionally, the step of acquiring the rotor position of the brushless dc motor detected by the motor position detector when the rotor of the brushless dc motor is detected to be in a stationary state includes:
controlling to inject high-frequency voltage signals into U, V, W phase lines of the brushless direct current motor pairwise according to a preset sequence and a preset period;
collecting bus currents IUV, IUW, IVU, IVW, IWU and IWV when UV, UW, VU, VW, WU and WV are injected into pulses;
calculating the time tUV, tUW, tVU, tVW, tWU and tWV of the current from one end to the other end of each phase line of the motor according to the bus currents IUV, IUW, IVU, IVW, IWU and IWV;
and calculating the position of the rotor of the brushless direct current motor according to the time difference among the time tUV, tUW, tVU, tVW, tWU and tWV.
Optionally, the injecting, by the non-inductive FOC control, two high-frequency voltage signals into the U, V, W three phase lines of the brushless dc motor in a preset period according to a preset sequence specifically includes: direct pulse injection detection or indirect high frequency signal injection detection.
Optionally, the lawn mower further comprises a fault indicator light, and the control method of the lawn mower further comprises:
when overcurrent protection is triggered, the fault indicator lamp flickers once;
when locked-rotor protection is triggered, the fault indicator lamp flickers twice;
when the open-phase protection is triggered, the fault indicator lamp flickers for three times;
when the undervoltage protection is triggered, the fault indicator lamp flickers four times.
The invention also provides a grass trimmer control device, which comprises a controller, a memory, a processor and a grass trimmer control program which is stored on the memory and can run on the processor; the processor realizes the grass trimmer control method when executing the grass trimmer control program.
The invention also provides a grass trimmer, which comprises the grass trimmer control device.
According to the technical scheme, the controller of the grass trimmer integrates the motor engine ME and the 8051 kernel, the controller acquires the voltage value of the storage battery of the grass trimmer and the voltage value of the speed regulation signal of the brushless direct current motor, which are acquired by the voltage acquisition circuit, compares the acquired voltage value of the storage battery with the undervoltage protection threshold value, compares the acquired voltage value of the speed regulation signal with the preset starting threshold value, and controls the brushless direct current motor to start according to the comparison result of the voltage value of the storage battery and the voltage value of the speed regulation signal, so that the starting reliability of the brushless direct current motor is improved. Because the non-inductive FOC controller and the non-inductive square wave controller are integrated in the motor engine ME, the number and the area of components of the control circuit board in the brushless direct current motor are reduced, the reliability of the brushless direct current motor in the grass mower is further improved, and meanwhile, the cost is also reduced. After the brushless direct current motor is started, the position of the rotor of the brushless direct current motor detected by the motor position detector is obtained, and the motor engine ME is controlled to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the position of the rotor of the brushless direct current motor, so that the brushless direct current motor can perform non-inductive FOC control operation or non-inductive square wave control operation, and the operation reliability of the grass trimmer is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a schematic flow chart illustrating a method for controlling a lawnmower according to an embodiment of the present invention;
FIG. 2 is a block diagram of an embodiment of a non-inductive FOC controller in the lawn mower control method of the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 100 | |
500 | |
| 200 | |
600 | |
| 300 | |
700 | |
| 400 | Three-phase full- |
800 | Electric machine |
The implementation, functional features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides a control method of a grass trimmer.
In an embodiment of the present invention, the control method is applied to a grass trimmer, the grass trimmer includes a storage battery, a controller and a brushless dc motor, the controller includes a motor engine ME, an 8051 kernel, a motor position detector for detecting a position of a motor rotor of the grass trimmer, and a voltage collecting circuit for collecting a voltage value of the storage battery of the grass trimmer and a voltage value of a speed regulation signal of the brushless dc motor, as shown in fig. 1, the control method includes:
step S100, acquiring a voltage value of a storage battery of the grass trimmer and a voltage value of a speed regulation signal of the brushless direct current motor, which are acquired by the voltage acquisition circuit;
step S200, when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold value, controlling the brushless direct current motor to start;
step S300, obtaining the rotor position of the brushless direct current motor detected by the motor position detector, and controlling the motor engine ME to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor.
In this embodiment, the motor engine ME is integrated on the brushless dc motor controller, and can implement the non-inductive FOC control and the non-inductive square wave control of the brushless dc motor. Meanwhile, the 8051 controller is also integrated on the controller of the brushless direct current motor, and the position of a motor rotor detected by the position detector in the brushless direct current motor, the motor rotating speed, the storage battery voltage value, the speed regulation signal voltage value, the preset starting threshold value, the undervoltage protection threshold value and other parameters can be configured, so that the integration level of the controller in the brushless direct current motor is improved, and compared with the interconnection among independent modules in the related art, the complexity of wiring is reduced, the size of a control circuit board is reduced, and the running reliability of the brushless direct current motor is improved.
In this embodiment, the motor of the grass mower in the grass mower control method may be a brushless dc motor, and it can be understood that the brushless dc motor is input by a dc power supply, and an inverter converts dc power into ac power, and meanwhile, because a mechanical commutator is replaced by an electronic commutator, the brushless dc motor has good speed regulation performance of the dc motor, and also has the advantages of simple structure, no commutation spark, reliable operation and easy maintenance of the ac motor.
In this embodiment, the voltage acquisition circuit may acquire the voltage value of the storage battery and the voltage value of the speed control signal of the brushless dc motor through the ADC sampling circuit, or may acquire the voltage value of the storage battery and the voltage value of the speed control signal of the brushless dc motor through the resistance voltage division circuit. In the scheme, the voltage value of the storage battery of the grass trimmer and the voltage value of the speed regulation signal of the brushless direct current motor, which are acquired by the voltage acquisition circuit, are acquired through the controller, the acquired voltage value of the storage battery is compared with the undervoltage protection threshold value, the acquired voltage value of the speed regulation signal is compared with the preset starting threshold value, and when the acquired voltage value of the speed regulation signal is greater than or equal to the preset starting threshold value and the acquired voltage value of the storage battery is greater than or equal to the undervoltage protection threshold value, the controller controls the brushless direct current motor to start.
In this embodiment, the motor position detector detects the position of the rotor of the brushless dc motor through back electromotive force detection, for example, in the related art, a three-phase back electromotive force detection circuit may be formed by a resistor, a capacitor, a comparator, and the like to obtain a sector where the rotor of the brushless dc motor is located, that is, a position where the rotor of the brushless dc motor is located. It can be understood that the motor position detector may obtain an initial position of the rotor of the brushless dc motor, and may also obtain a current position of the rotor of the brushless dc motor, where the current position of the rotor is a real-time position during an operation process after the brushless dc motor is started. And controlling a motor engine ME in the brushless direct current motor to operate a non-inductive FOC control mode or a non-inductive square wave control mode through the position of a motor rotor detected by a motor position detector in the brushless direct current motor. The reliability of the brushless direct current motor in the grass mower is improved by integrating the non-inductive FOC controller and the non-inductive square wave controller into the motor engine ME in the brushless direct current motor.
In the above embodiment, the non-inductive FOC control mode in which the motor engine ME operates, that is, the non-inductive FOC controller integrated in the motor engine ME operates the non-inductive magnetic field orientation control algorithm, that is, the vector control algorithm, is to control the exciting current and the torque current of the motor according to the magnetic field orientation principle by measuring and controlling the stator current vector of the motor, so as to make the three-phase ac motor equivalent to dc motor control. The field orientation control is understood that the rotor field orientation is a control mode similar to that of a direct current motor, and a coordinate transformation method is utilized to decompose a stator current of the alternating current motor into a field component current (namely, an excitation current) and a torque component current (namely, a load current) and respectively control the field component current and the torque component current, namely, the flux current component and the torque current component are completely decoupled, so that the dynamic performance similar to that of a direct current speed regulating device is obtained. Furthermore, the non-inductive FOC controller obtains the target working current of the motor of the grass trimmer and converts a three-phase static coordinate system into a two-phase rotating coordinate system through coordinate transformation, so that the three-phase alternating-current coupled stator current is converted into mutually orthogonal torque and excitation components which are independently decoupled, and the aim of directly controlling the torque by controlling the torque current similarly to a separately excited direct-current motor is achieved.
In the present embodiment, as shown in fig. 2, the non-inductive FOC controller in the mower controller includes a PI controller 100, a first coordinate inverter 200, a second coordinate inverter 300, a three-phase full-bridge inverter 400, a first coordinate converter 500, a second coordinate converter 600, and a rotor position estimator 700; wherein the content of the first and second substances,
a reference current is input to a first end of the PI controller 100, a second end of the PI controller 100 is connected to a first end of the first coordinate inverter 200, a second end of the first coordinate inverter 200 is connected to a first end of the second coordinate inverter 300, a second end of the second coordinate inverter 300 is connected to a first end of the three-phase full-bridge inverter 400, a second end of the three-phase full-bridge inverter 400 is connected to the motor 800, a first end of the first coordinate converter 500 is connected between a second end of the three-phase full-bridge inverter 400 and the motor 800, a second end of the first coordinate converter 500 is connected to a first end of the second coordinate converter 600, a second end of the second coordinate converter 600 is connected to a first end of the PI controller 100, the first coordinate inverter 200 is connected to the second coordinate converter 600, and a first end of the rotor position estimator 700 is connected to the first coordinate inverter 200 and the second coordinate converter 200 The rotor position estimator 700 is connected between the second terminal of the first coordinate transformer 500 and the first terminal of the second coordinate transformer 600, 600.
In the embodiment, for a non-inductive FOC controller in a grass trimmer controller, a first coordinate inverter 200 is PARK inverse transformation in the non-inductive FOC controller, a three-phase full-bridge inverter is three-phase full-bridge inversion in the non-inductive FOC controller, a second coordinate inverter 300 is SVPWM transformation in the non-inductive FOC controller, a first coordinate converter 500 is CLARKE transformation in the non-inductive FOC controller, a second coordinate converter 600 is PARK transformation in the non-inductive FOC controller, the three-phase full-bridge inverter 400 and the motor 800 have automatic acquisition of motor running phase currents, the phase currents comprise Ia, Ib and Ic, it can be understood that the automatic acquisition can be different sampling modes including single resistance sampling, double resistance sampling, three resistance sampling and power device internal resistance sampling, coordinate axis transformation in the non-inductive FOC controller comprises the first coordinate converter 500 and the second coordinate converter 600, coordinate axis transformation in the non-inductive FOC controller includes CLAE transformation and PARK transformation, the CLAK transformation is used for transforming three-phase rotating current, 58Ib, Ia and IQ signals, 35 and upright current signals, 3535, a QREQ signal feedback coordinate axis is used for obtaining a rotating current feedback signal used for feeding back a rotor shaft voltage signal, a rotating current signal, a QREQ signal used for feeding back a vertical rotating axis signal for obtaining a rotating coordinate signal, a rotating coordinate signal used for a rotating axis signal for controlling a rotating shaft, a rotating shaft controlling a rotating shaft, a rotating shaft controlling a rotating shaft, a rotating shaft rotating.
It should be noted that the rotor position estimator may be an anti-tangential method, a PLL phase-locked loop method, or the like, so as to obtain the motor angle signal θ and the angular velocity signal Speed, thereby filtering the high-frequency noise of the motor of the lawn mower, enabling the brushless dc motor to start smoothly, and improving the operational reliability of the brushless dc motor in the lawn mower.
In the above embodiment, the motor engine ME operates in the non-inductive square wave control mode, i.e. in the six-step control without hall, and in one power cycle, the brushless dc motor has only six transition states, or the stator current of the brushless dc motor has six states (i.e. the three-phase bridge arm has six switch states). Each current state can be regarded as a vector moment in one direction, six vectors are regularly converted step by step, the rotation direction of the vectors determines the rotation direction of the brushless direct current motor, the rotation direction of the brushless direct current motor is clockwise or anticlockwise, and the rotor of the brushless direct current motor can rotate synchronously. In a non-inductive square wave control mode, two quantities are mainly controlled, one is a tube opening state corresponding to the position of a motor rotor, and the position of the brushless direct current motor rotor is obtained through a back electromotive force signal so as to determine the tube opening state; and the second is the control of PWM duty ratio, and the current of the brushless direct current motor is controlled by controlling the size of the duty ratio, thereby controlling the torque and the rotating speed of the brushless direct current motor.
In the embodiment, for a non-inductive square wave controller in a grass trimmer controller, the controller in the brushless direct current motor forcibly pulls the motor in a software reversing mode, hardware for switching to a motor engine ME is automatically reversed by software reversing when the back electromotive force zero-crossing points of the brushless direct current motor are detected for multiple times, the motor engine ME can automatically record the time of two adjacent back electromotive force zero-crossing points as a 60-degree time reference, an initial follow current shielding angle is preset for the motor engine ME according to an 8051 kernel, and the reversing angle is delayed after the back electromotive force zero-crossing points of the brushless direct current motor are detected, so that follow current shielding time and delayed reversing time can be obtained, the motor engine ME automatically starts a comparator corresponding to the current suspension for back electromotive force zero-crossing point detection after the follow current shielding time is ended, and the motor engine ME automatically delays the set reversing angle after the back electromotive force zero-crossing points of the brushless direct current, and when the delay time is over, the reversing is automatically carried out.
It is understood that the zero crossing of the back electromotive force of the brushless dc motor is detected, that is, the motor position detector detects the position of the rotor of the brushless dc motor. The non-inductive square wave controller integrated with the grass trimmer controller realizes automatic recording of 60-degree phase change reference time, automatic shielding of follow current time, automatic recording of phase change time from detection of rotor position signals and automatic control of three-phase six-path PWM output.
It should be noted that the storage battery can supply power to the controller and the brushless direct current motor to ensure that the grass trimmer can work normally.
In the above embodiment, as for the grass mower control method, in the technical scheme of the invention, the controller of the grass mower integrates the motor engine ME and the 8051 kernel, and the controller acquires the voltage value of the storage battery of the grass mower and the voltage value of the speed regulation signal of the brushless dc motor, which are acquired by the voltage acquisition circuit, compares the acquired voltage value of the storage battery with the undervoltage protection threshold, compares the acquired voltage value of the speed regulation signal with the preset startup threshold, and controls the brushless dc motor to start up according to the comparison result of the voltage value of the storage battery and the voltage value of the speed regulation signal, so that the starting reliability of the brushless dc motor is improved. Because the non-inductive FOC controller and the non-inductive square wave controller are integrated in the motor engine ME, the number and the area of components of the control circuit board in the brushless direct current motor are reduced, the reliability of the brushless direct current motor in the grass mower is further improved, and meanwhile, the cost is also reduced. After the brushless direct current motor is started, the position of the rotor of the brushless direct current motor detected by the motor position detector is obtained, and the motor engine ME is controlled to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the position of the rotor of the brushless direct current motor, so that the brushless direct current motor can perform non-inductive FOC control operation or non-inductive square wave control operation, and the operation reliability of the grass trimmer is improved.
In an embodiment, when the voltage value of the speed regulation signal is greater than or equal to a preset startup threshold and the voltage value of the storage battery is greater than or equal to an under-voltage protection threshold, the step of controlling the brushless dc motor to start further includes:
and acquiring the initial position of the rotor of the brushless direct current motor detected by the motor position detector.
In this embodiment, the motor position detection algorithm is run in the motor position detector, and the motor position detection algorithm is used to obtain the initial position of the motor rotor, where the high-frequency voltage signal is injected into each phase of the brushless dc motor stator to observe the feedback difference caused by the unbalanced inductance of the phases by using the salient polarity of the brushless dc motor, that is, the phenomenon of unbalanced inductance between phases of the motor stator due to different positions of the brushless dc motor rotor, so as to obtain the current static position information of the brushless dc motor rotor. It is understood that the initial position of the motor rotor when the motor rotor is currently stationary is obtained here, i.e. the initial position of the motor rotor obtained by the motor position detector. Thereby improving the starting stability of the grass trimmer.
In an embodiment, the lawn mower further includes a status indicator, and the step of controlling the brushless dc motor to start when the voltage value of the speed regulation signal is greater than or equal to a preset startup threshold and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold further includes:
and controlling the state indicator lamp to light green.
In this embodiment, after the step of obtaining the voltage value of the storage battery of the lawn mower and the voltage value of the speed control signal of the brushless dc motor, which are collected by the voltage collecting circuit, is performed, the method for controlling the lawn mower further includes:
when the voltage value of the speed regulating signal is smaller than a preset starting threshold value, controlling the state indicator lamp to light a yellow lamp;
and when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is less than an undervoltage protection threshold value, controlling the state indicator lamp to light a red lamp.
It can be understood that, because the controller obtains the voltage value of the storage battery and compares the voltage value with the undervoltage protection threshold value in the lawn mower, after the controller obtains the voltage value of the speed regulating signal and compares the voltage value with the preset starting threshold value, when the voltage value of the speed regulating signal is greater than or equal to the preset starting threshold value and the voltage value of the storage battery is greater than or equal to the undervoltage protection threshold value, the controller controls the status indicator lamp to light green, namely, the controller controls the brushless direct current motor to start. And when the voltage value of the speed regulating signal is smaller than the preset starting threshold value, controlling the state indicating lamp to light a yellow lamp, namely, indicating that the acquired voltage value of the speed regulating signal of the brushless direct current motor does not reach the preset starting threshold value, and the brushless direct current motor does not act. And when the voltage value of the speed regulating signal is greater than or equal to the preset starting threshold value and the voltage value of the storage battery is smaller than the undervoltage protection threshold value, controlling the state indicator lamp to light a red lamp, namely, indicating that the acquired voltage value of the storage battery of the brushless direct current motor does not reach the undervoltage protection threshold value, and the brushless direct current motor does not act. Therefore, the reliability of the operation of the brushless direct current motor in the grass trimmer is improved.
In an embodiment, the step of obtaining the rotor position of the brushless dc motor detected by the motor position detector and controlling the motor engine ME to operate in the non-inductive FOC control mode or the non-inductive square wave control mode according to the rotor position of the brushless dc motor further includes:
when the brushless direct current motor rotor is detected to be in a static state, acquiring the position of the brushless direct current motor rotor detected by the motor position detector;
and controlling a motor engine ME to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor.
It can be understood that, when the brushless dc motor rotor is detected to be in a static state, the motor rotor position of the lawn mower detected by the motor position detector is obtained, that is, the target current of the brushless dc motor is preset to 0, if the brushless dc motor is in a static state, the current flowing through the brushless dc motor is almost 0, at this time, the motor position detector detects the position of the motor rotor, and the motor engine ME in the brushless dc motor is controlled to operate in the non-inductive FOC control mode or the non-inductive square wave control mode according to the position of the motor rotor when the brushless dc motor is in a static state.
In an embodiment, the step of obtaining the rotor position of the brushless dc motor detected by the motor position detector when the rotor of the brushless dc motor is detected to be in a stationary state includes:
controlling to inject high-frequency voltage signals into U, V, W phase lines of the brushless direct current motor pairwise according to a preset sequence and a preset period;
collecting bus currents IUV, IUW, IVU, IVW, IWU and IWV when UV, UW, VU, VW, WU and WV are injected into pulses;
calculating the time tUV, tUW, tVU, tVW, tWU and tWV of the current from one end to the other end of each phase line of the motor according to the bus currents IUV, IUW, IVU, IVW, IWU and IWV;
and calculating the position of the rotor of the brushless direct current motor according to the time difference among the time tUV, tUW, tVU, tVW, tWU and tWV.
In this embodiment, the direct pulse injection detection method is to inject a series of high frequency voltage signals into the stator winding of the brushless dc motor in sequence, and U, V, W three phase lines are connected with each other, the current signals obtained by each energization of the operational amplifier circuit are amplified and then compared with the negative terminal of the comparator to detect the time taken by the current from one end of the phase line to the other end of the phase line, and the difference between the voltage or current signals fed back by the stator of the brushless dc motor is observed, and then the corresponding difference between the three-phase inductances of the motor is determined according to the signal difference, and finally the position information of the rotor of the motor is estimated, so that the grass trimmer can know the angle of the current rotor in advance when starting, and prevent the brushless dc motor from generating large current when starting and further damaging the controller and the brushless dc motor, the reliability of the brushless direct current motor is improved.
Further, the motor position detector injects a high-frequency voltage signal into each phase of the motor, and the method for acquiring the initial position information of the rotor when the motor is currently stationary may be a direct pulse injection detection method or an indirect high-frequency signal injection detection method.
In one embodiment, the lawn mower further comprises a fault indicator light, and the control method of the lawn mower further comprises the following steps:
when overcurrent protection is triggered, the fault indicator lamp flickers once;
when locked-rotor protection is triggered, the fault indicator lamp flickers twice;
when the open-phase protection is triggered, the fault indicator lamp flickers for three times;
when the undervoltage protection is triggered, the fault indicator lamp flickers four times.
The grass trimmer has the advantages that the grass trimmer has overcurrent protection, locked rotor protection, open-phase protection, undervoltage protection and the like, and when the fault indicator lamp flickers once in the running process of the brushless direct current motor in the grass trimmer, the grass trimmer is indicated to trigger the overcurrent protection; when the fault indicator lamp flickers twice, the grass trimmer is indicated to trigger locked-rotor protection; when the fault indicator light flickers for three times, the grass trimmer is indicated to trigger open-phase protection; when the fault indicator light flickers for four times, the grass trimmer triggers the undervoltage protection. Therefore, the safety of the grass trimmer in the operation process is improved, and the operation reliability of the grass trimmer is improved.
In addition, the invention also provides a grass trimmer control device, which comprises a controller, a memory, a processor and a grass trimmer control program which is stored on the memory and can run on the processor; the processor realizes the grass trimmer control method when executing the grass trimmer control program. Because the lawn mower control device adopts all technical schemes of all the embodiments, the lawn mower control device at least has all the beneficial effects brought by the technical schemes of the embodiments, and details are not repeated.
In addition, the invention also provides a grass trimmer, which comprises the grass trimmer control device, and the grass trimmer adopts all the technical schemes of all the embodiments, so that the grass trimmer at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted.
The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A control method of a grass trimmer is applied to the grass trimmer and is characterized in that the grass trimmer comprises a storage battery, a controller and a brushless direct current motor, the controller comprises a motor engine ME, an 8051 kernel, a motor position detector for detecting the position of a motor rotor of the grass trimmer and a voltage acquisition circuit for acquiring the voltage value of the storage battery of the grass trimmer and the voltage value of a speed regulation signal of the brushless direct current motor, and the control method of the grass trimmer comprises the following steps:
acquiring a voltage value of a storage battery of the grass trimmer and a voltage value of a speed regulation signal of the brushless direct current motor, which are acquired by the voltage acquisition circuit;
when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold value, controlling the brushless direct current motor to start;
and acquiring the rotor position of the brushless direct current motor detected by the motor position detector, and controlling the motor engine ME to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor.
2. The method for controlling a lawn mower according to claim 1, wherein said step of controlling said brushless dc motor to start when said speed-adjusting signal voltage value is greater than or equal to a preset start-up threshold and said battery voltage value is greater than or equal to an undervoltage protection threshold further comprises:
and acquiring the initial position of the rotor of the brushless direct current motor detected by the motor position detector.
3. The method of claim 1, wherein the lawn mower further comprises a status indicator, and the step of controlling the brushless dc motor to start when the voltage value of the speed regulation signal is greater than or equal to a preset start-up threshold and the voltage value of the storage battery is greater than or equal to an undervoltage protection threshold further comprises:
and controlling the state indicator lamp to light green.
4. The method of claim 3, wherein after the step of obtaining the voltage value of the battery of the lawnmower and the voltage value of the speed signal of the brushless DC motor, the voltage acquisition circuit acquires, the method further comprises:
when the voltage value of the speed regulating signal is smaller than a preset starting threshold value, controlling the state indicator lamp to light a yellow lamp;
and when the voltage value of the speed regulating signal is greater than or equal to a preset starting threshold value and the voltage value of the storage battery is less than an undervoltage protection threshold value, controlling the state indicator lamp to light a red lamp.
5. The method of claim 1, wherein said step of obtaining the rotor position of the brushless dc motor detected by the motor position detector and controlling the motor engine ME to operate in either the non-inductive FOC control mode or the non-inductive square wave control mode according to the rotor position of the brushless dc motor further comprises:
when the brushless direct current motor rotor is detected to be in a static state, acquiring the position of the brushless direct current motor rotor detected by the motor position detector;
and controlling a motor engine ME to operate a non-inductive FOC control mode or a non-inductive square wave control mode according to the rotor position of the brushless direct current motor.
6. The lawnmower control method according to claim 5, wherein the step of acquiring the position of the rotor of the brushless dc motor detected by the motor position detector when the rotor of the brushless dc motor is detected to be in a stationary state comprises:
controlling to inject high-frequency voltage signals into U, V, W phase lines of the brushless direct current motor pairwise according to a preset sequence and a preset period;
collecting bus currents IUV, IUW, IVU, IVW, IWU and IWV when UV, UW, VU, VW, WU and WV are injected into pulses;
calculating the time tUV, tUW, tVU, tVW, tWU and tWV of the current from one end to the other end of each phase line of the motor according to the bus currents IUV, IUW, IVU, IVW, IWU and IWV;
and calculating the position of the rotor of the brushless direct current motor according to the time difference among the time tUV, tUW, tVU, tVW, tWU and tWV.
7. The mower control method according to claim 6, wherein the non-inductive FOC control injects two high-frequency voltage signals into U, V, W phase lines of the brushless DC motor in a preset sequence and in a preset period, specifically: direct pulse injection detection or indirect high frequency signal injection detection.
8. The method of claim 1, wherein the lawnmower further comprises a fault indicator, the method further comprising:
when overcurrent protection is triggered, the fault indicator lamp flickers once;
when locked-rotor protection is triggered, the fault indicator lamp flickers twice;
when the open-phase protection is triggered, the fault indicator lamp flickers for three times;
when the undervoltage protection is triggered, the fault indicator lamp flickers four times.
9. A grass trimmer control device is characterized by comprising a controller, a memory, a processor and a grass trimmer control program which is stored on the memory and can run on the processor; the processor, when executing the lawnmower control program, implements the lawnmower control method according to any one of claims 1 to 8.
10. A lawnmower, characterized in that it comprises a lawnmower control apparatus according to claim 9.
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