阅读说明：本技术 割草机控制方法、装置及割草机 (Mower control method and device and mower ) 是由 毕磊 于 2019-10-18 设计创作，主要内容包括：本发明公开一种割草机控制方法、装置及割草机,该割草机包括无刷三相电机和用于检测无刷三相电机转子位置的反电动势检测电路,该割草机控制方法包括：获取割草机静止时的电机转子初始位置；根据获取的电机转子初始位置控制无刷三相电机启动,并运行电机低速模式；在电机低速模式下,获取电机转子位置,并计算获得无刷三相电机的转速；若无刷三相电机的电机转速大于第一预设转速时,控制无刷三相电机运行电机正常模式；根据电机正常模式,若无刷三相电机的转速小于所述第二预设转速时,控制无刷三相电机返回电机低速模式；其中,电机正常模式的电机转速大于电机低速模式的电机转速。本发明技术方案提升割草机中无刷三相电机的运行可靠性。(The invention discloses a mower control method, a mower control device and a mower, wherein the mower comprises a brushless three-phase motor and a back electromotive force detection circuit for detecting the position of a rotor of the brushless three-phase motor, and the mower control method comprises the following steps: obtaining the initial position of a motor rotor when the mower is static; controlling the brushless three-phase motor to start according to the obtained initial position of the motor rotor, and operating a low-speed mode of the motor; in a low-speed mode of the motor, the position of a motor rotor is obtained, and the rotating speed of the brushless three-phase motor is obtained through calculation; if the motor rotating speed of the brushless three-phase motor is greater than a first preset rotating speed, controlling the brushless three-phase motor to operate in a motor normal mode; according to the normal mode of the motor, if the rotating speed of the brushless three-phase motor is less than the second preset rotating speed, controlling the brushless three-phase motor to return to the low-speed mode of the motor; and the motor rotating speed in the normal mode of the motor is greater than that in the low-speed mode of the motor. The technical scheme of the invention improves the operation reliability of the brushless three-phase motor in the mower.)

1. A mower control method for a mower including a brushless three-phase motor and a back electromotive force detection circuit for detecting a rotor position of the brushless three-phase motor, the mower control method comprising:

obtaining the initial position of a motor rotor when the mower is static;

controlling the brushless three-phase motor to start according to the obtained initial position of the motor rotor, and operating a motor low-speed mode;

under the low-speed mode of the motor, the position of a motor rotor is obtained, and the rotating speed of the brushless three-phase motor is obtained through calculation according to the position of the motor rotor;

if the motor rotating speed of the brushless three-phase motor is greater than a first preset rotating speed, controlling the brushless three-phase motor to operate in a motor normal mode;

according to the normal mode of the brushless three-phase motor for operating the motor, if the rotating speed of the brushless three-phase motor is less than the second preset rotating speed, controlling the brushless three-phase motor to return to the low-speed mode of the motor; the first preset rotating speed of the brushless three-phase motor is larger than the second preset rotating speed.

2. The mower control method of claim 1, wherein said step of obtaining an initial position of the motor rotor at rest of the mower comprises:

injecting pulse signals into U, V, W phase lines of the motor in pairs according to a preset sequence;

collecting bus currents IUV, IUW, IVW, IVU, IWU and IWV when UV, UW, VW, VU, WU and WV are injected into pulses;

calculating the time tUV, tUW, tVW, tVU, tWU, 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, IWU and IWV;

and calculating the initial position of the rotor of the motor according to the time difference among the time tUV, tUW, tVW, tVU, tWU and tWV.

3. The mower control method according to claim 2, wherein the injecting of pulse signals into the U, V, W three phase lines of the brushless three-phase motor in pairs according to the preset sequence is specifically: direct pulse injection detection and indirect high frequency signal injection detection.

4. The method of claim 1, wherein the step of controlling the brushless three-phase motor to return to the motor low-speed mode when the rotation speed of the brushless three-phase motor is less than the second predetermined rotation speed according to the normal motor operation mode of the brushless three-phase motor further comprises:

and under the normal mode of the brushless three-phase motor, if the rotating speed of the brushless three-phase motor is greater than or equal to a second preset rotating speed, continuing to operate under the normal mode of the motor.

5. The mower control method of claim 1, wherein said first predetermined speed of said brushless three-phase motor is in a range of 500RPM to 1000 RPM.

6. The mower control method of claim 1, wherein said second predetermined speed of said brushless three-phase motor is in a range of 300RPM to 800 RPM.

7. A mower control apparatus, characterized in that said mower control apparatus comprises a brushless three-phase motor controller and a mower control method according to any one of claims 1 to 6.

8. A mower control device as claimed in claim 7 wherein said brushless three phase motor control device comprises a controller, an inverter and a back EMF detection circuit;

the control end of the controller is connected with the controlled end of the inverter, the output end of the inverter is connected with the input end of the brushless three-phase motor, the acquisition end of the counter electromotive force detection circuit is connected with the input end of the brushless three-phase motor, and the output end of the counter electromotive force detection circuit is connected with the input end of the controller;

the back electromotive force detection circuit is used for detecting the rotor position of the brushless three-phase motor according to the input signal of the brushless three-phase motor and outputting a position detection signal to the controller;

the controller is used for processing the position detection signal and outputting a control signal to the inverter;

and the inverter is used for outputting preset alternating current according to the control signal so as to drive the brushless three-phase motor.

9. The mower control device of claim 8, wherein said back emf detection circuit comprises a comparator sampling circuit, an ADC sampling circuit, and a BEMF sampling circuit;

the comparator sampling circuit is used for collecting a back electromotive force signal of the brushless three-phase motor in a low-speed mode of the motor and outputting the back electromotive force signal to the controller;

the ADC sampling circuit is used for collecting a back electromotive force signal of the brushless three-phase motor in a low-speed mode of the motor and outputting the back electromotive force signal to the controller;

and the BEMF sampling circuit is used for collecting back electromotive force signals of the brushless three-phase motor in a motor normal mode and outputting the back electromotive force signals to the controller.

10. A lawnmower, characterized in that it comprises a mower control device according to any one of claims 7 to 9.

Technical Field

The invention relates to the technical field of motor control, in particular to a mower control method and device and a mower.

Background

At present, garden electric tools are widely applied, such as a mower, a trimmer and the like. The drive system of the existing garden electric tool generally adopts an inductive square wave scheme. The scheme has the problems of high motor rotating speed, complex working conditions and the like, so that hall devices are inaccurate in position detection, and the motor is large in running vibration. If a common non-inductive three-phase BLDC motor is adopted, the low-speed estimation position is inaccurate, large-torque starting cannot be provided, the motor cannot be applied to a mower, and the reliability of garden electric tools such as the mower and the trimmer is reduced.

Disclosure of Invention

The invention mainly aims to provide a mower control method and device and a mower, and aims to improve the operation reliability of a brushless three-phase motor in the mower.

In order to achieve the above object, the present invention provides a mower control method, the mower including a brushless three-phase motor and a back electromotive force detection circuit for detecting a rotor position of the brushless three-phase motor, the mower control method including:

obtaining the initial position of a motor rotor when the mower is static;

controlling the brushless three-phase motor to start according to the obtained initial position of the motor rotor, and operating a motor low-speed mode;

under the low-speed mode of the motor, the position of a motor rotor is obtained, and the rotating speed of the brushless three-phase motor is obtained through calculation according to the position of the motor rotor;

if the motor rotating speed of the brushless three-phase motor is greater than a first preset rotating speed, controlling the brushless three-phase motor to operate in a motor normal mode;

according to the normal mode of the brushless three-phase motor for operating the motor, if the rotating speed of the brushless three-phase motor is less than the second preset rotating speed, controlling the brushless three-phase motor to return to the low-speed mode of the motor; the first preset rotating speed of the brushless three-phase motor is larger than the second preset rotating speed.

Optionally, the step of obtaining the initial position of the rotor of the motor when the mower is at rest comprises:

injecting pulse signals into U, V, W phase lines of the motor in pairs according to a preset sequence;

collecting bus currents IUV, IUW, IVW, IVU, IWU and IWV when UV, UW, VW, VU, WU and WV are injected into pulses;

calculating the time tUV, tUW, tVW, tVU, tWU, 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, IWU and IWV;

and calculating the initial position of the rotor of the motor according to the time difference among the time tUV, tUW, tVW, tVU, tWU and tWV.

Optionally, the injecting two pulse signals into the U, V, W phase lines of the brushless three-phase motor according to the preset sequence specifically includes: direct pulse injection detection and indirect high frequency signal injection detection.

Optionally, the step of controlling the brushless three-phase motor to return to the motor low-speed mode according to the normal mode of the brushless three-phase motor when the rotation speed of the brushless three-phase motor is less than the second preset rotation speed further includes:

and under the normal mode of the brushless three-phase motor, if the rotating speed of the brushless three-phase motor is greater than or equal to a second preset rotating speed, continuing to operate under the normal mode of the motor.

Optionally, the first preset rotation speed of the brushless three-phase motor ranges from 500RPM to 1000 RPM.

Optionally, the second preset rotation speed of the brushless three-phase motor ranges from 300RPM to 800 RPM.

The invention also provides a mower control device which comprises the brushless three-phase motor controller and the mower control method.

Optionally, the brushless three-phase motor control device comprises a controller, an inverter and a back electromotive force detection circuit;

the control end of the controller is connected with the controlled end of the inverter, the output end of the inverter is connected with the input end of the brushless three-phase motor, the acquisition end of the counter electromotive force detection circuit is connected with the input end of the brushless three-phase motor, and the output end of the counter electromotive force detection circuit is connected with the input end of the controller;

the back electromotive force detection circuit is used for detecting the rotor position of the brushless three-phase motor according to the input signal of the brushless three-phase motor and outputting a position detection signal to the controller;

the controller is used for processing the position detection signal and outputting a control signal to the inverter;

and the inverter is used for outputting preset alternating current according to the control signal so as to drive the brushless three-phase motor.

Optionally, the back electromotive force detection circuit includes a comparator sampling circuit, an ADC sampling circuit, and a BEMF sampling circuit;

the comparator sampling circuit is used for collecting a back electromotive force signal of the brushless three-phase motor in a low-speed mode of the motor and outputting the back electromotive force signal to the controller;

the ADC sampling circuit is used for collecting a back electromotive force signal of the brushless three-phase motor in a low-speed mode of the motor and outputting the back electromotive force signal to the controller;

and the BEMF sampling circuit is used for collecting back electromotive force signals of the brushless three-phase motor in a motor normal mode and outputting the back electromotive force signals to the controller.

The invention also provides a mower which comprises the mower control device.

The technical scheme of the invention is that the mower comprises a brushless three-phase motor and a back electromotive force detection circuit for detecting the position of a rotor of the brushless three-phase motor. In the scheme, the controller in the brushless three-phase motor acquires the initial position of the motor rotor when the mower is static through the back electromotive force detection circuit, and controls the brushless three-phase motor to start and operate the motor in a low-speed mode according to the acquired initial position of the motor rotor. And under the condition of the low-speed mode of the motor, the brushless three-phase motor controls the counter electromotive force detection circuit to obtain the current motor rotor position of the mower, and calculates the current rotor rotating speed of the brushless three-phase motor according to the current motor rotor position. Comparing the current rotating speed of a motor rotor with a first preset rotating speed, and controlling the brushless three-phase motor to operate in a motor normal mode when the motor rotating speed of the brushless three-phase motor is greater than the first preset rotating speed; and when the motor rotating speed of the brushless three-phase motor is less than or equal to a first preset rotating speed, controlling the brushless three-phase motor to keep operating in a motor low-speed mode. Under the condition that the brushless three-phase motor operates in a motor normal mode, comparing the current rotating speed of a motor rotor with a second preset rotating speed, and controlling the brushless three-phase motor to return to a motor low-speed mode to operate when the motor rotating speed of the brushless three-phase motor is lower than the second preset rotating speed; and when the motor rotating speed of the brushless three-phase motor is greater than or equal to a second preset rotating speed, controlling the brushless three-phase motor to continuously operate in a motor normal mode. In the scheme, the first preset rotating speed of the brushless three-phase motor is greater than the second preset rotating speed. The back electromotive force detection circuit is used for detecting the initial position and the current position of the rotor of the brushless three-phase motor, so that the position of the rotor of the brushless three-phase motor in the mower can be accurately detected relative to a rotor position detector with a Hall sensor, and the running noise of the brushless three-phase motor in the mower is reduced; meanwhile, the current rotating speed of the rotor in the brushless three-phase motor is compared with the preset rotating speed, so that the running stability of the brushless three-phase motor in the mower is improved. The technical scheme of the invention improves the operation reliability of the brushless three-phase motor in the mower.

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 lawn mower according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a mower control device according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a back electromotive force detection circuit in the mower control device according to an embodiment of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				10	Controller	41	Comparator sampling circuit
20	Inverter with a voltage regulator	42	ADC sampling circuit
				30	Brushless three-phase motor	43	BEMF sampling circuit
40	Counter electromotive force detection circuit

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 mower, which is applied to the mower, wherein the mower comprises a brushless three-phase motor and a counter electromotive force detection circuit for detecting the position of a rotor of the brushless three-phase motor, and the control method is widely applied to garden electric tools such as the existing mowers, trimmers and the like, and the motors in the mower have the problems of uneven magnetic steel installation or asymmetrical hall installation due to a plurality of pole pairs of the motors. If the motor in the mower adopts a sensible sine scheme, the problems of high motor rotating speed, complex working condition and the like are solved, so that the hall device position detection is inaccurate, and the motor has large running vibration. If the motor in the mower adopts a common non-inductive three-phase BLDC motor, the low-speed estimation position is inaccurate, large-torque starting cannot be provided, and the motor cannot be applied to the mower.

In order to solve the above problem, in an embodiment of the present invention, as shown in fig. 1, the lawn mower control method includes:

s100, acquiring an initial position of a motor rotor when the mower is static;

step S200, controlling the brushless three-phase motor to start according to the obtained initial position of the motor rotor, and operating a motor low-speed mode;

step S300, acquiring the position of a motor rotor in the low-speed mode of the motor, and calculating according to the position of the motor rotor to obtain the rotating speed of the brushless three-phase motor;

step S400, if the motor rotating speed of the brushless three-phase motor is greater than a first preset rotating speed, controlling the brushless three-phase motor to operate in a motor normal mode;

step S500, according to a normal mode of the brushless three-phase motor, if the rotating speed of the brushless three-phase motor is less than the second preset rotating speed, controlling the brushless three-phase motor to return to a low-speed mode of the motor; the first preset rotating speed of the brushless three-phase motor is larger than the second preset rotating speed.

In this embodiment, in order to solve among the lawn mower the more magnet steel that leads to of motor pole pair number uneven distribution or hall sensor installation asymmetry, traditional correlation technique can lead to hall sensor position detection inaccurate, arouses that the noise is big, and the vibration is big, inefficiency scheduling problem. This scheme acquires motor rotor initial position when the lawn mower is static through the brushless three-phase motor controller of lawn mower to control brushless three-phase motor and get into motor low-speed mode, the position of brushless three-phase motor rotor is estimated in real time to rethread back electromotive force detection circuitry, in order to control brushless three-phase motor, thereby promote the accuracy that brushless three-phase motor rotor position detected, reduce lawn mower motor noise and vibration, improved the efficiency of the brushless three-phase motor of lawn mower. Meanwhile, the brushless three-phase motor controller in the mower can calculate the real-time rotating speed of the brushless three-phase motor according to the estimated real-time position of the rotor of the brushless three-phase motor, and the controller compares the calculated real-time rotating speed with the preset rotating speed, so that the stability of the output electromagnetic torque of the brushless three-phase motor in the mower is realized, the electromagnetic noise and vibration of the mower are reduced, and the running stability of the brushless three-phase motor in the mower is improved.

In the present embodiment, regarding the brushless three-phase motor in the mower, it can be understood that the mower adopts a dc power input, and converts the dc power into an ac power through an inverter, so as to input the dc power into the brushless three-phase motor. The brushless three-phase motor is a three-phase alternating current motor with rotor position feedback, and the electronic commutator replaces a mechanical commutator, so that the brushless direct current motor has good speed regulation performance of the direct current motor, and has the advantages of simple structure, no commutation spark, reliable operation and easy maintenance of the alternating current motor.

It should be noted that, in the related art, the brushless dc motor having the hall needs to be matched with the hall sensor, which is relatively complex, and brings adverse factors to the reliability and the manufacturing process of the motor, for example: the installation hall sensor can increase the volume of motor, if the signal transmission line of sensor is more, that causes the interference to the motor very easily, and the operational environment and the temperature of motor reduce hall sensor's reliability, if the installation to hall sensor is inaccurate in addition, can cause the runnability problem of motor.

Aiming at the problems, the Hall-free direct current brushless motor runs stably and is reliable to start, a rotor Hall sensor is not directly used, but a rotor position signal is needed to control the phase change of the motor in the running process of the motor, and the position signal detection of the rotor mostly adopts the detection of stator voltage, current and the like to estimate the position of the rotor. In the scheme, the brushless three-phase motor does not have a Hall sensor in the mower, and the position and speed data of the rotor in the brushless three-phase motor are estimated by detecting the voltage, the current and the like of the stator, so that the use of the sensor in the mower is reduced, and the cost of the mower is reduced.

In this embodiment, the position of the rotor is estimated by detecting the stator voltage, the stator current, and the like, that is, the back electromotive force signal of the brushless three-phase motor is collected by the back electromotive force detection circuit, so as to detect the current input by the brushless three-phase motor to obtain the position signal of the rotor. It can be understood that the counter electromotive force detection circuit detects zero-crossing points of counter electromotive forces of the phases of the brushless three-phase motor, so that several key positions of a rotor of the brushless three-phase motor can be obtained to realize the phase change control of the brushless direct-current motor without the hall sensor. Furthermore, the input voltage of the brushless three-phase motor is controlled to control the rotation of the rotor of the brushless three-phase motor, so that the rotating speed of the rotor of the brushless three-phase motor can reach the maximum rotating speed which can be reached by mechanical design, the torque of the brushless three-phase motor after starting is improved, and the running reliability of the brushless three-phase motor is improved.

It should be noted that, in the present embodiment, the first preset rotation speed is greater than the second preset rotation speed, so that a preset hysteresis rotation speed exists in the operation process of the brushless three-phase motor of the lawn mower, where the preset hysteresis rotation speed may be 200RPM, 250RPM, 300RPM, and the like, and is not limited herein. When the preset hysteresis rotation speed is 200RPM, namely, the brushless three-phase motor in the mower is in operation, the preset hysteresis rotation speed is 200 revolutions per minute. Through the arrangement of the preset hysteresis rotating speed, the brushless three-phase motor in the mower is prevented from always circulating.

Based on the embodiment, the technical scheme of the invention adopts the mower to comprise the brushless three-phase motor and the back electromotive force detection circuit for detecting the rotor position of the brushless three-phase motor. In the scheme, the controller in the brushless three-phase motor acquires the initial position of the motor rotor when the mower is static through the back electromotive force detection circuit, and controls the brushless three-phase motor to start and operate the motor in a low-speed mode according to the acquired initial position of the motor rotor. And under the condition of the low-speed mode of the motor, the brushless three-phase motor controls the counter electromotive force detection circuit to obtain the current motor rotor position of the mower, and calculates the current rotor rotating speed of the brushless three-phase motor according to the current motor rotor position. Comparing the current rotating speed of a motor rotor with a first preset rotating speed, and controlling the brushless three-phase motor to operate in a motor normal mode when the motor rotating speed of the brushless three-phase motor is greater than the first preset rotating speed; and when the motor rotating speed of the brushless three-phase motor is less than or equal to a first preset rotating speed, controlling the brushless three-phase motor to keep operating in a motor low-speed mode. Under the condition that the brushless three-phase motor operates in a motor normal mode, comparing the current rotating speed of a motor rotor with a second preset rotating speed, and controlling the brushless three-phase motor to return to a motor low-speed mode to operate when the motor rotating speed of the brushless three-phase motor is lower than the second preset rotating speed; and when the motor rotating speed of the brushless three-phase motor is greater than or equal to a second preset rotating speed, controlling the brushless three-phase motor to continuously operate in a motor normal mode. In the scheme, the first preset rotating speed of the brushless three-phase motor is greater than the second preset rotating speed. The back electromotive force detection circuit is used for detecting the initial position and the current position of the rotor of the brushless three-phase motor, so that the position of the rotor of the brushless three-phase motor in the mower can be accurately detected relative to a rotor position detector with a Hall sensor, and the running noise of the brushless three-phase motor in the mower is reduced; meanwhile, the current rotating speed of the rotor in the brushless three-phase motor is compared with the preset rotating speed, so that the running stability of the brushless three-phase motor in the mower is improved. The technical scheme of the invention improves the operation reliability of the brushless three-phase motor in the mower.

In one embodiment, the step of obtaining the initial position of the rotor of the motor when the mower is at rest comprises:

injecting pulse signals into U, V, W phase lines of the motor in pairs according to a preset sequence;

collecting bus currents IUV, IUW, IVW, IVU, IWU and IWV when UV, UW, VW, VU, WU and WV are injected into pulses;

calculating the time tUV, tUW, tVW, tVU, tWU, 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, IWU and IWV;

and calculating the initial position of the rotor of the motor according to the time difference among the time tUV, tUW, tVW, tVU, tWU and tWV.

In this embodiment, the back electromotive force detection circuit has a motor position detection algorithm, and the obtaining of the initial position of the rotor of the brushless three-phase motor by the motor position detection algorithm is to inject pulse signals into each phase of the stator of the motor by using some salient poles of the dc brushless motor, that is, the phenomenon of unbalance of inductances between phases of the stator of the motor due to different positions of the rotor of the motor, and observe the feedback difference caused by the unbalance of the inductances, so as to obtain the position information of the rotor of the motor when the rotor is stationary. It is understood that the position information obtained when the motor rotor is stationary is the initial position of the motor rotor obtained by the back electromotive force detection circuit.

In this embodiment, the brushless three-phase motor controller injects a pulse signal into each phase of the motor, and the method for acquiring the initial position information of the rotor when the motor is stationary may be a direct pulse injection detection method or an indirect high-frequency signal injection detection method.

Further, the direct pulse injection detection method is to supply the same short-time current or voltage signals to three phases of the brushless three-phase motor stator, namely, to inject a series of pulse signals to the motor stator winding, observe the voltage or current signal difference fed back by the motor stator, then determine the corresponding motor three-phase inductance difference according to the signal difference, and finally estimate and obtain the position information of the motor rotor, thereby achieving higher position detection accuracy and simultaneously saving detection elements in the motor. The indirect high-frequency signal injection detection method is to inject specific high-frequency voltage or current into the brushless three-phase motor, detect current or voltage signals corresponding to the brushless three-phase motor, and estimate the salient pole position of the motor through algorithm transformation in the controller, so as to estimate the position information of the motor rotor, thereby realizing speed and position control with high precision and high dynamic performance. It is understood that the indirect high frequency signal injection detection method may be a rotating high frequency voltage signal injection method and a pulsating high frequency voltage signal injection method, which are not limited herein.

In one embodiment, the first preset rotation speed of the brushless three-phase motor ranges from 500RPM to 1000 RPM. It is understood that the first preset rotation speed may be 500RPM, 700RPM, 1000RPM, etc., without limitation thereto. The second preset rotating speed of the brushless three-phase motor ranges from 300RPM to 800 RPM. It is understood that the second preset rotation speed may be 300RPM, 500RPM, 8000RPM, etc., without limitation thereto.

It should be noted that, when the preset hysteresis rotation speed is 200RPM, the first preset rotation speed is 500RPM, and the second preset rotation speed is 300 RPM. The control method of the mower is that the brushless three-phase motor is controlled to operate in a motor normal mode when the rotating speed of the brushless three-phase motor is greater than 500RPM, and the brushless three-phase motor is controlled to keep the motor low-speed mode to operate when the rotating speed of the brushless three-phase motor is less than or equal to 500 RPM. When the brushless three-phase motor is in the normal mode operation of the motor, the rotating speed of the brushless three-phase motor is less than 300RPM, the brushless three-phase motor is controlled to return to the low-speed mode operation of the motor, and when the brushless three-phase motor is in the normal mode operation of the motor, the rotating speed of the brushless three-phase motor is greater than or equal to 300RPM, the brushless three-phase motor is controlled to continuously keep the normal mode operation of the motor.

In order to solve the above problems, the present invention further provides a mower control device including a brushless three-phase motor controller and the mower control method as described above. Since the mower control device adopts all technical solutions of all the embodiments, at least all the beneficial effects brought by the technical solutions of the embodiments are achieved, and no further description is given here.

In one embodiment, as shown in fig. 2, the brushless three-phase motor control device includes a controller 10, an inverter 20, and a back electromotive force detection circuit 40;

the control end of the controller 10 is connected to the controlled end of the inverter 20, the output end of the inverter 20 is connected to the input end of the brushless three-phase motor 30, the collecting end of the counter electromotive force detection circuit 40 is connected to the input end of the brushless three-phase motor 30, and the output end of the counter electromotive force detection circuit 40 is connected to the input end of the controller 10;

the back electromotive force detection circuit 40 is configured to detect a rotor position of the brushless three-phase motor 30 according to an input signal of the brushless three-phase motor 30, and output a position detection signal to the controller 10;

the controller 10 is configured to process the position detection signal and output a control signal to the inverter 20;

the inverter 20 is configured to output a preset ac power according to the control signal to drive the brushless three-phase motor 30.

It is understood that the brushless three-phase motor control device is also provided with a power circuit for outputting direct current power, and the power circuit can supply power to the controller and the inverter in the control device.

In this embodiment, as shown in fig. 3, the back electromotive force detection circuit 40 includes a comparator sampling circuit 41, an ADC sampling circuit 42, and a BEMF sampling circuit 43;

the comparator sampling circuit 41 is configured to collect a back electromotive force signal of the brushless three-phase motor 30 in a motor low-speed mode, and output the back electromotive force signal to the controller 10;

the ADC sampling circuit 42 is configured to collect a back electromotive force signal of the brushless three-phase motor 30 in a motor low-speed mode, and output the back electromotive force signal to the controller 10;

the BEMF sampling circuit 43 is configured to collect a back electromotive force signal of the brushless three-phase motor 30 in the motor normal mode, and output the back electromotive force signal to the controller 10.

In addition, in order to solve the above problems, the present invention further provides a lawn mower including the lawn mower control device, and since the lawn mower adopts all the technical solutions of all the above embodiments, at least all the advantageous effects brought by the technical solutions of the above embodiments are provided, and no further description is given here.

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.