Electric mower

Abstract

The invention discloses an electric mower. The electric mower comprises a brushless motor; in the starting stage of the brushless motor, the controller is configured to obtain an initial sector in a plurality of motor sector positions where a rotor is located based on a pulse injection method; and acquiring the rotor position of the rotor in the initial sector based on a high-frequency signal injection method so as to control the brushless motor to start, the high-frequency signal comprises a periodic signal, and the positive half cycle of the periodic signal and the negative half cycle of the signal are different in amplitude. The position detection of the rotor of the electric mower is more accurate.

Description

Technical Field

[0001] This application relates to an outdoor garden power tool, specifically an electric lawnmower. Background Technology

[0002] An electric lawnmower is a mechanical tool used for trimming lawns, vegetation, etc. A lawnmower consists of a mowing element (such as a blade), a mowing motor, a walking mechanism, control components, and a power supply. The mowing motor is the main working component.

[0003] Lawn mower motor control primarily employs a field-oriented control (FOC) strategy. In FOC control, rotor position detection is necessary to ensure normal motor operation. Common rotor position detection methods include sensor-based and sensorless methods. Sensorless methods measure the back electromotive force (EMF), deduce the motor speed from this back EMF, and then determine the rotor position by comparing it to the actual speed. However, this method is prone to inaccuracies under varying load conditions.

[0004] This section provides background information related to this application, which is not necessarily prior art. Summary of the Invention

[0005] One object of this application is to solve or at least alleviate some or all of the aforementioned problems. Therefore, one object of this application is to provide an electric lawnmower with more accurate rotor position detection.

[0006] To achieve the above objectives, this application adopts the following technical solution: An electric lawnmower includes: a brushless motor for driving mowing blades or wheels; the brushless motor including a stator and a rotor having multiple windings; a drive circuit for supplying power to the brushless motor from a power supply mechanism; and a controller configured to receive at least one signal related to the phase current of the brushless motor, detect the angular position of the rotor based on the phase current of the brushless motor, and output a drive signal to the drive circuit based on the angular position of the rotor to control the operation of the brushless motor; during the start-up phase of the brushless motor, the controller is configured to: obtain an initial sector among multiple sector positions of the rotor based on a pulse injection method; and obtain the rotor position of the rotor in the initial sector based on a high-frequency signal injection method to control the start-up of the brushless motor; the high-frequency signal includes a periodic signal, wherein the positive half-cycle and the negative half-cycle of the periodic signal have different amplitudes.

[0007] In some embodiments, during the start-up phase of the brushless motor, the controller uses a flux linkage observer method to calculate the rotor position and speed of the brushless motor. When the speed is greater than or equal to a speed threshold and the start-up time is greater than or equal to a time threshold, the controller uses the rotor position estimated by the flux linkage observer method to control the brushless motor to commutate and enter the acceleration phase.

[0008] In some embodiments, the speed threshold is greater than or equal to 9% of the rated speed.

[0009] In some embodiments, the time threshold is greater than or equal to 500ms.

[0010] In some embodiments, during the startup phase, the controller is also configured to calculate the speed of the brushless motor using a flux linkage observer method, and control the brushless motor to enter a stall protection mode when the speed of the brushless motor is less than or equal to 0.5% of the rated speed and the startup time is greater than or equal to 2.5s.

[0011] In some embodiments, during the startup phase, the controller is also configured to calculate the speed of the brushless motor using a flux linkage observer method, and control the brushless motor to enter a stall protection mode when the speed of the brushless motor is less than or equal to 3% of the rated speed and the startup time is greater than or equal to 5 seconds.

[0012] In some embodiments, the amplitude of the positive half-cycle is set to the sum of the amplitude of the negative half-cycle and a preset DC bias.

[0013] In some embodiments, the electric lawnmower includes a push lawnmower, a lawnmower robot, and a manned lawnmower.

[0014] An electric lawnmower includes: a brushless motor for driving mowing blades or a drive wheel; the brushless motor includes a stator and a rotor having multiple windings; a drive circuit for supplying power to the brushless motor from a power supply mechanism; and a controller configured to receive at least one signal related to the phase current of the brushless motor, detect the angular position of the rotor based on the phase current of the brushless motor, and output a drive signal to the drive circuit based on the angular position of the rotor to control motor operation; during the start-up phase of the brushless motor, the controller is configured to: obtain an initial sector among multiple sector positions of the rotor based on a pulse injection method; and obtain the rotor position of the rotor in the initial sector based on a high-frequency signal injection method to control the start-up of the brushless motor; the high-frequency signal includes a periodic signal; during the high-frequency signal injection process, a DC bias is injected during the positive half-cycle or the negative half-cycle of the periodic signal of the phase current, such that the amplitude of the signal during the positive or negative half-cycle of the injected DC bias is greater than or equal to 10% and less than or equal to 20% of the bus voltage.

[0015] In some embodiments, the amplitude of the positive half-cycle of the periodic signal is set to the sum of the amplitude of the negative half-cycle and a preset DC bias.

[0016] The advantages of this application are: using pulse injection method to obtain the initial sector among multiple sector positions of the rotor, and using high-frequency signal injection method to accurately obtain rotor position information in low-speed or stationary states of the motor. During the high-frequency signal injection process, a DC bias is injected in the positive half-cycle or negative half-cycle of the periodic signal so that the amplitude of the signal in the positive or negative half-cycle of the injected DC bias is greater than or equal to 10% and less than or equal to 20% of the bus voltage, thereby increasing the ratio of the quadrature axis component iq and the direct axis component id of the rotor current of the lawnmower motor, and accurately obtaining rotor position information in low-speed or stationary states. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an outdoor walking device according to one embodiment of this application; Figure 2 This is a schematic diagram of the structure of an outdoor walking device as one embodiment of this application from another perspective; Figure 3 This is a schematic diagram illustrating the power supply mechanism adapted to different vehicles as one embodiment of this application; Figure 4 This is a schematic diagram of the walking mechanism and control mechanism as an embodiment of this application; Figure 5 This is a schematic diagram of a portion of the structure of the braking mechanism and the traveling mechanism as an embodiment of this application; Figure 6 This is a control block diagram of the brake mechanism and brake motor as an embodiment of this application; Figure 7 This is another control block diagram of the brake mechanism and brake motor as an embodiment of this application; Figure 8 This is a third control block diagram of the brake mechanism and brake motor as an embodiment of this application; Figure 9 This is a control block diagram of a sensing device, braking mechanism, and brake motor as an embodiment of this application; Figure 10 This is a flowchart of a control method for a manned lawnmower as an embodiment of this application; Figure 11 This is a schematic diagram of the structure of a human-computer interaction mechanism as an embodiment of this application; Figure 12 This is a block diagram of a human-computer interaction mechanism system as an embodiment of this application; Figure 13 This is a control principle diagram of an operating component as an embodiment of this application; Figure 14This is a schematic diagram of the structure of the operating circuit board as an embodiment of this application; Figure 15 This is a control block diagram of the operating component and the walking motor as an embodiment of this application; Figure 16 This is another control principle diagram of the operating element as one embodiment of this application; Figure 17 This is a schematic diagram of a lawn mowing component as one embodiment of this application; Figure 18 This is a schematic diagram of a lawnmower motor according to one embodiment of this application, showing the stator and rotor of the motor; Figure 19 This is a circuit diagram of a lawnmower motor as an embodiment of this application; Figure 20 This is a schematic diagram of the sector of the rotor of a lawnmower motor according to one embodiment of this application; Figure 21 This is a schematic diagram of the control circuit of a lawnmower motor as an embodiment of this application; Figure 22 This is a flowchart illustrating a control method for an electric lawnmower as an embodiment of this application; Figure 23 This is a flowchart illustrating another control method for an electric lawnmower as an embodiment of this application; Figure 24 This is a circuit diagram of the power supply circuit of an electric lawnmower as an embodiment of this application; Figure 25 This is a schematic diagram of the structure of a lawnmower motor according to one embodiment of this application, showing the motor housing and cables; Figure 26 This is a schematic diagram of a motor housing and cable seal of a lawnmower motor as an embodiment of this application; Figure 27 This is a schematic diagram of another motor housing and cable seal of a lawnmower motor as one embodiment of this application; Figure 28 This is a schematic diagram of a third type of motor housing and cable seal for a lawnmower motor, as one embodiment of this application; Figure 29 This is an internal schematic diagram of the third type of motor housing and cable seal of the lawn mowing motor as an embodiment of this application; Figure 30 This is a schematic diagram of a lawnmower motor as one embodiment of this application from another perspective; Figure 31a yes Figure 3 A perspective view of the first connector of the power supply mechanism and the battery pack. Figure 31byes Figure 3 A perspective view of the second connector of the power supply mechanism and the battery pack. Figure 32 This is a schematic diagram of the second connector and the third battery pack as one embodiment of this application; Figure 33 yes Figure 1 A 3D diagram of the power supply mechanism for outdoor walking equipment. Detailed Implementation

[0018] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0019] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0020] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0021] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0022] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, %, 1% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 1 degree, 1 degree or more) added to or subtracted from the indicated angle.

[0023] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0024] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0025] In this application, the terms "controller," "processor," "central processing unit," "CPU," and "MCU" are used interchangeably. When using the unit "controller," "processor," "central processing unit," "CPU," or "MCU" to perform a specific function, unless otherwise stated, these functions may be performed by a single or multiple of the aforementioned units.

[0026] In this application, the terms "device," "module," or "unit" are used to describe devices that can be implemented in hardware or software to perform a specific function.

[0027] In this application, the terms “calculation,” “judgment,” “control,” “determine,” “identify,” etc., refer to the operation and process of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0028] like Figure 1 , Figure 2 and Figure 3 As shown, the outdoor walking device 100 disclosed in this application is specifically a wheeled work vehicle or outdoor work vehicle, such as an electric lawnmower 200 or an electric lawn mower, which can be operated by a user to mow lawns or other vegetation. Optionally, a manned lawnmower 200a can be operated by a user sitting or standing on it to mow lawns and other vegetation. In this specification, the directions forward, backward, left, right, up, and down are described as... Figure 1 The directions shown are defined as follows. When a user is riding on the outdoor walking device 100 located on the ground, the direction the user faces is defined as forward, the direction behind is defined as rear, the direction to the left is defined as left, the direction to the right is defined as right, the direction closest to the ground is defined as downward, and the direction furthest from the ground is defined as upward. Of course, the outdoor walking device 100 disclosed in this application also includes an all-terrain vehicle 100c (UTV, Utility Vehicle). In related technologies, the all-terrain vehicle 100c includes a four-wheeled all-terrain vehicle (ATV, All Terrain Vehicle), a multi-functional all-terrain vehicle, and a recreational vehicle. In addition, the outdoor walking device 100 disclosed in this application also includes a manned snowplow, a push lawnmower, a push snowplow 100d, and an electric motorcycle, etc.

[0029] The outdoor walking device 100 includes a vehicle body 10, a power supply mechanism 20, and a walking mechanism 40. The vehicle body 10 includes a frame 11 that extends substantially in a front-to-back direction. The frame 11 is used to mount the power supply mechanism 20 and the walking mechanism 40. The power supply mechanism 20 is used to provide electrical energy to the power unit 30.

[0030] The walking mechanism 40 includes at least a walking wheel set 41. The walking wheel set 41 includes walking wheels 411 and 412, which are connected to the vehicle body 10 to support the vehicle body 10 and drive the vehicle body 10 to move.

[0031] In this embodiment, the power supply mechanism 20 includes a battery pack 21 and a connector 22 for mounting the battery pack 21 to connect it to the outdoor walking device 100. The battery pack 21, in conjunction with a corresponding power circuit, supplies power to at least the power unit 30. The power unit 30 outputs power to drive the walking mechanism 40, enabling the outdoor walking device 100 to walk according to operation.

[0032] The battery pack 21 is detachably connected to the connector 22, which is detachably mounted to the outdoor mobility device 100 so that it can be removed to be adapted to other electrical devices. These other electrical devices include, but are not limited to, an all-terrain vehicle 100c, a push lawnmower, a push snow sweeper 100d, and a manned lawnmower 200a. See details... Figure 3 As shown, the power supply mechanism 20 of the outdoor walking equipment 100 can be detached and removed from the outdoor walking equipment 100, and then installed on the all-terrain vehicle 100c, the push lawnmower, the push snow sweeper 100d, the riding lawnmower 100a, and the standing lawnmower 100b to supply power to these electrical devices and enable the functions of the aforementioned power supply devices.

[0033] Continue as Figures 1 to 3 as well as Figures 5 to 9 , Figure 16 As shown, when the outdoor walking device 100 is specifically an electric lawnmower 200, the electric lawnmower 200 includes a mowing assembly 80, including mowing blades 81 and a mowing motor 82 for driving the mowing blades 81. This application discloses an electric lawnmower 200 including a push-type or rear-walking lawnmower, a manned lawnmower 200a, and a mowing robot.

[0034] In this embodiment, the electric lawnmower 200 is taken as an example as a manned lawnmower 200a. The manned lawnmower 200a includes: a vehicle body 10, a power supply mechanism 20, a mowing assembly 80, a walking mechanism 40, an operating mechanism 50, and a support mechanism 90. The vehicle body 10 includes a frame 11, which extends substantially in a front-rear direction. The frame 11 is used to mount the mowing assembly 80, the walking mechanism 40, the operating mechanism 50, and the support mechanism 90. The mowing assembly 80 includes mowing blades 81 and a mowing motor 82 for driving the mowing blades 81. The operating mechanism 50 includes an operating element 511. The operating element 511 is operated by a user to control the manned lawnmower 200a to move forward, backward, and turn. Exemplarily, the operating element 511 is a joystick. In some embodiments, the operating mechanism 50 may also include a steering wheel assembly. The support mechanism 90 is used to support the operator and is mounted on the vehicle body 10. Optionally, the support mechanism 90 includes a seat 91. Seat 91 is mounted to frame 11 for a user to sit on. In other alternative embodiments, support mechanism 90 also includes a platform for the user to stand on. Power supply mechanism 20 provides power to the mowing assembly 80 and walking mechanism 40, enabling the manned lawnmower 200a to be used as a power tool capable of carrying a person. Compared to fuel-powered manned lawnmowers 200a, electric manned lawnmowers 200a are more environmentally friendly and energy-efficient. In some embodiments, manned lawnmower 200a also includes a grass collection device for collecting grass clippings cut by mowing assembly 80. The grass collection device includes a grass basket assembly detachably mounted behind seat 91.

[0035] The walking mechanism 40 includes a walking wheel set 41 and a walking motor 42. The walking wheel set 41 includes a rear walking wheel 411 and a front walking wheel 412. The rear walking wheel 411 includes a left rear walking wheel 411L and a right rear walking wheel 411R. The front walking wheel 412 includes a left front walking wheel 412L and a right front walking wheel 412R. The walking motor 42 drives the rear walking wheel 411 or the front walking wheel 412 to rotate, thereby enabling the manned lawnmower 200a to walk. Optionally, the number of walking motors 42 can be one, two, three, or four. In this embodiment, there are two walking motors 42, which respectively drive the left rear walking wheel 411L and the right rear walking wheel 411R, allowing the manned lawnmower 200a to turn in directions other than the forward / backward direction. For ease of reference, the motor 42 that drives the left rear wheel 411L is designated as the first motor 42L, and the motor 42 that drives the right rear wheel 411R is designated as the second motor 42R.

[0036] like Figure 5 As shown, the manned lawnmower 200a also includes a braking mechanism 46, which performs braking actions to brake the walking mechanism 40. The braking mechanism 46 includes a braking state for braking the walking component and a releasing state for releasing the walking component. The braking mechanism 46 responds to a user's trigger command to enter the braking state and the releasing state. When the manned lawnmower 200a needs to adjust its operating speed due to road conditions or working conditions during operation, such as needing to brake and decelerate while going downhill or needing to pause briefly while going uphill, the user outputs a braking trigger command to cause the braking mechanism 46 to enter the braking state. The braking mechanism 46 then decelerates the walking mechanism 40 to a predetermined position and eventually stops at that position. The braking trigger command, depending on the user's trigger level, allows the braking mechanism 46 to perform both deceleration braking and complete stopping braking.

[0037] The braking mechanism 46 includes a pedal 461, a pull rope 463 connected to the pedal 461, and a brake 464. In this embodiment, the brake 464 is configured as a brake drum. The brake drum is connected to the travel mechanism 40 to reduce the rotational speed of the travel mechanism 40. The pull rope 463 connects the pedal 461 and the brake drum. Exemplarily, when the pedal 461 is operated by an operator, such as by pressing down to rotate it about the pedal pivot 462, or by pushing or rotating it to rotate it about the pedal pivot 462, the pull rope 463 is driven, thereby pulling the brake drum to brake the travel mechanism 40. In this embodiment, the brake drum is connected to the rear travel wheel 411. The working principle of the brake drum is prior art and will not be described separately here. The brake 464 can also be a disc brake, a band brake, a floating brake 4, etc.

[0038] The manned lawnmower 200a also includes a brake motor 465, which is connected to a brake mechanism 46. The brake motor 465 drives the brake mechanism 46 to switch between a braking state and a released state. The manned lawnmower 200a also includes a control mechanism 70 for controlling the operation of the manned lawnmower 200a. The control mechanism 70 includes a controller 72 and a detection component 74. In this embodiment, the controller 72 controls at least the operation of the walking mechanism 40 and the mowing assembly 80. Figure 6 As shown, the controller 72 is configured to, upon receiving an abnormal signal, control the brake motor 465 to operate, driving the brake mechanism 46 to switch from a released state (solid line position of pedal 461) to a braking state (dashed line position of pedal 461). The abnormal signal includes indications of an abnormality in at least one of the following: the walking mechanism 40, the mowing assembly 80, the power supply mechanism 20, or the control mechanism 70. In this embodiment, by configuring the brake motor 465, which can be controlled by the controller 72, to drive the brake mechanism 46 to switch between braking and released states, the manned lawnmower 200a can automatically brake under certain conditions. This prevents delayed braking due to special working conditions or operator skill issues, reducing potential harm to the operator. Meanwhile, in this embodiment, when the controller 72 detects an abnormality in at least one of the walking mechanism 40, the mowing assembly 80, the power supply mechanism 20, or the control mechanism 70, it can control the brake motor 465 to drive the brake mechanism 46 to brake the walking mechanism 40, thus ensuring the braking reliability of the brake mechanism 46 and preventing brake failure due to abnormalities. Through the dual protection of electronic control and mechanical operation, the driving safety of the manned lawnmower 200a is ensured.

[0039] In this embodiment, a transmission assembly 466 is provided between the brake motor 465 and the pedal 461. The brake motor 465 is connected to the travel mechanism 40 to drive the pedal 461 to rotate around the pedal pivot 462 by a preset angle, thereby driving the pull rope 463 to drive the brake drum to brake the travel mechanism 40. By mechanically driving the brake mechanism 46 through the brake motor 465, automatic braking is achieved, and the braking control is more stable.

[0040] like Figure 7 As shown, in some embodiments, to reduce the computational complexity of controller 72 and thus its computational load, dual controllers 72 are used for control. For example, controller 72 employs a dual-MCU configuration. Controller 72 includes a first controller 72a for controlling the operation of the walking motor 42 or the lawnmower motor 82. A second controller 72b is used to control the operation of the brake motor 465. It is understood that the first controller 72a and the second controller 72b can be located on the same control circuit board, or they can be located on two separate control circuit boards.

[0041] The control mechanism 70 also includes a communication component 78, which is used to enable communication between the first controller 72a and the second controller 72b. Exemplary communication protocols include asynchronous serial communication, serial bus communication, or parallel communication. These communication protocols do not affect the substance of this application.

[0042] like Figure 7 As shown, in some embodiments, to ensure the reliability and anti-interference capability of automatic braking control, the power supply mechanism 20 includes an independent power source that independently powers the brake motor 465. For ease of reference, the power supply mechanism 20 includes at least a first battery pack 21a and a second battery pack 21b, wherein the first battery pack 21a powers at least the travel motor 42, and the second battery pack 21b powers at least the brake motor 465. The first battery pack 21a and the second battery pack 21b are different. For example, the first battery pack 21a and the second battery pack 21b are not the same battery pack 21 or the same battery pack group. For example, the nominal voltage, nominal capacity, or discharge capability of the first battery pack 21a and the second battery pack 21b are different. For example, the cell material or cell type of the first battery pack 21a and the second battery pack 21b are different. For example, the energy of the first battery pack 21a and the second battery pack 21b are different. The energy of the first battery pack 21a is greater than the energy of the second battery pack 21b. The first battery pack 21a is a battery pack with an energy of 1.5 kWh or greater. In some embodiments, the first battery pack 21a has an energy of 3 kWh or more. In some embodiments, the first battery pack 21a has an energy of 4 kWh or more. In some embodiments, the second battery pack 21b has an energy of 0.1 kWh or more. In some embodiments, the second battery pack 21b has an energy of 0.4 kWh or more. In some embodiments, the second battery pack 21b has an energy of 0.6 kWh or more. Of course, the energy of the first battery pack 21a and the second battery pack 21b can be the same or different. In this embodiment, the first battery pack 21a is a lithium iron phosphate cell, and the second battery pack 21b can be a lithium battery cell, or alternatively, nickel-cadmium batteries, graphene, or other materials can be used to achieve different combinations of battery characteristics. In some embodiments, the first battery pack 21a can also be a supercapacitor, also known as an electrochemical capacitor. In some embodiments, the rated voltage of the first battery pack 21a and the second battery pack 21b is greater than or equal to 40V and less than or equal to 80V. The first battery pack 21a can provide electrical energy to the second battery pack 21b to charge it. When the first battery pack 21a is in a discharging state, it can charge the second battery pack 21b.

[0043] like Figure 8As shown, in some embodiments, the walking motor 42 and the brake motor 465 use the same battery pack 21, but different power supply circuits. For example, the walking motor 42 is powered by a first power supply circuit 79a, and the brake motor 465 is powered by a second power supply circuit 79b. The first power supply circuit 79a and the second power supply circuit 79b are different. In some embodiments, the walking motor 42 and the brake motor 465 are powered by different battery packs and power supply circuits. For example, the first battery pack 21a powers the walking motor 42 through the first power supply circuit 79a, and the second battery pack 21b powers the brake motor 465 through the second power supply circuit 79b. By powering the brake motor 465 with a separate power supply, even if the walking motor 42 or the lawnmower motor 82 experiences an abnormal power outage, the driving force of the brake motor 465 on the brake mechanism 46 remains unaffected.

[0044] In this embodiment, the abnormal signals of the control mechanism 70 include: abnormal control of the travel motor 42, such as the first travel motor 42L and / or the second travel motor 42R issuing signals of over-temperature, over-voltage, over-current, or abnormality of the detection component 74. It also includes: other signals indicating the need for braking, such as the support mechanism 90, for example, the seat 91 switch being released.

[0045] Abnormal conditions of the power supply mechanism 20 include: the power supply mechanism 20 failing to discharge or having an excessively low or high discharge voltage, or an excessively high or low discharge current. In some embodiments, abnormal conditions of the power supply mechanism 20 may also include: the power supply mechanism 20 disconnecting the current circuit, for example, including powering off according to an operator's instruction, or the power supply mechanism 20 entering a protection program and having its current circuit disconnected by the control mechanism 70, such as overcurrent protection, overvoltage protection, or overtemperature protection.

[0046] like Figure 9As shown, in some embodiments, the manned lawnmower 200a further includes a sensing device 92, which is configured to sense obstacles in the direction of travel of the manned lawnmower 200a. The sensing device 92 is communicatively connected to the controller 72. The controller 72 is configured to change the operating state of the travel motor 42 based on the feedback signal from the sensing device 92, thereby changing the direction of the manned lawnmower 200a, or to control the brake motor 465 to drive the brake mechanism 46 from a released state to a braking state based on the feedback signal from the sensing device 92. By setting the sensing device 92 and controlling the brake motor 465 according to the signal from the sensing device 92, when an obstacle is sensed in the direction of travel, the sensing device 92 sends a feedback signal to the controller 72, and the controller 72 controls the travel motor 42 and the brake motor 465 according to the feedback signal. The control method can be selected according to the actual situation. If the obstacle is stationary and the manned lawnmower 200a is in motion, the controller 72 controls the brake motor 465 of the manned lawnmower 200a to gradually brake the walking mechanism 40, causing the walking mechanism 40 to slow down and stop before colliding with the obstacle, thus avoiding a collision. Alternatively, the controller 72 controls the walking motor 42 of the manned lawnmower 200a to steer before colliding with the obstacle, thus avoiding a collision. If the obstacle is in motion, the controller 72 controls the manned lawnmower 200a to steer, thus avoiding a collision, achieving automatic obstacle avoidance. This solves the problem of collisions caused by the user's failure to operate in time to avoid obstacles. The sensing device 924 can be an infrared sensor capable of detecting obstacles; or it can be a distance sensor capable of detecting the distance to the obstacle.

[0047] like Figure 10 As shown, based on the same concept, this application also provides a control method for a manned lawnmower 200a. The method includes the following steps: S701: The controller receives an abnormal signal indicating an abnormal condition of at least one of the following: the walking mechanism, the mowing assembly, the power supply mechanism, or the control mechanism.

[0048] S702: The brake motor operates to drive the brake mechanism to switch from the release state to the braking state.

[0049] S703: Braking mechanism, braking travel mechanism.

[0050] In this embodiment, the controller 72 is further configured to: when the brake motor 465 drives the brake mechanism 46 into a braking state, upon receiving a start-allowed signal from the travel motor 42, control the brake motor 465 to rotate to release the force applied to the brake mechanism 46, thereby disengaging the automatic braking control and causing the brake mechanism 46 to switch from a braking state to a released state.

[0051] In this embodiment, when the controller 72 determines that there are no abnormal outputs from the following components, the controller 72 issues a start-allow signal for the walking motor 42, including: no abnormalities in the first walking motor 42L and the second walking motor 42R, the operating element 511 being in a start-allowed state, the seat 91 being in a start-allowed state, the switch assembly 61b (start switch or key) being in a start-allowed state, and the parking brake mechanism 44 being in an unlocked state. The controller 72 issues the start-allow signal. That is, when all the above conditions are met, the controller 72 issues a start-allow signal, and upon receiving the start signal, the controller 72 drives the walking motor 42 and / or the lawnmower motor to start.

[0052] See Figure 2 and Figures 11 to 12 As shown, in this embodiment, the manned lawnmower 200a further includes a human-machine interaction mechanism 60. In this embodiment, the outdoor walking device 100 includes a display device 60a for providing feedback, i.e., information prompts, to the user. The display device 60a can be, for example, an audio prompter, a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, or an organic electroluminescent (EL) display. The display device 60a includes a display screen 61, a switch assembly 61b, and a plurality of operation buttons 61c. In some embodiments, the display device 60a includes a touchscreen or a control screen, such that the switch assembly 61b and the plurality of operation buttons 61c are all integrated onto the screen. The touchscreen or control screen includes resistive, capacitive, infrared, and surface acoustic wave touchscreens. In this embodiment, the display screen 61 reflects the operating status of the outdoor walking device 100 on the display interface 61a. The display interface 61a is understood as the display area directly observed by the user.

[0053] The display interface 61a can display different status information as needed. For example, it can display the walking speed of the walking mechanism 40, the rotation speed of the working elements, the energy efficiency status of the outdoor walking device 100, the remaining power of the battery pack 21, and information such as normal braking or release status. It can also display parking or stopping prompts, parking release or start prompts, etc., based on user operation commands.

[0054] For example, the display interface 61a should at least provide feedback on the power-on status of the brake motor 465, the working status of the brake mechanism 46, and any abnormal warnings for the brake motor 465, such as braking abnormality warnings and release abnormality warnings. These abnormality alarm prompts include the display interface 61a displaying illuminated icons, flashing icons, or special colors. It also includes displaying special codes, special symbols, and other alarm content that can be identified according to the instruction manual.

[0055] In some embodiments, the controller 72 is further configured to, when the brake motor 465 drives the brake mechanism 46 into a braking state, control the brake motor 465 to rotate to release the force applied to the brake mechanism 46 upon receiving a drive signal from the travel motor 42. In some embodiments, when the travel motor 42 receives a drive signal, the travel motor 42 starts to rotate, and the brake motor 465 automatically releases the force applied to the brake mechanism 46, thus automatically releasing the brake.

[0056] like Figures 1 to 4 ,as well as Figures 13 to 15 As shown, the manned lawnmower 200a of this application is equipped with two sets of control lever assemblies, left and right, and the steering and straight-line speed of the vehicle are controlled according to the tilt angle of the two sets of control lever assemblies 51.

[0057] In this embodiment, the walking wheel assembly 41 includes a left walking wheel (see...). Figure 4 The front left-side travel wheel 412L and rear left-side travel wheel 411L (shown) and the right-side travel wheel (see...) Figure 4 The front right travel wheel 412R and the rear right travel wheel 411R are shown; the travel motor 42 includes a first travel motor 42L and a second travel motor 42R for driving the left travel wheel and the right travel wheel, respectively.

[0058] The joystick assembly can be gripped by the user via a left operating element 511L and a right operating element 511R. The first travel motor 42L and the second travel motor 42R are independently controlled by the operation of the corresponding left operating element 511L and right operating element 511R. In this embodiment, the right operating element 511R is used as an example, and the right operating element 511R will be referred to as operating element 511 in subsequent embodiments, but this is not intended to limit the scope of this application.

[0059] The manned lawnmower 200a also includes a position detection device 52. The position detection device 52 includes a first sensor 521 for detecting the position of the operating member 511. The first sensor 521 emits a first output signal. It also includes a detection calibration device 53, which includes a second sensor 531 for detecting the position of the operating member 511 and emitting a second output signal. The controller 72 is configured to: control the operation of the travel motor 42 based on the first output signal to at least change the speed and direction of the manned lawnmower 200a; and control the travel motor 42 to stop or enter a speed-limited mode when the ratio of the first output signal to the second output signal exceeds a preset range. In this embodiment, the position detection device 52 and the detection calibration device 53 are used on one side of the operating member 511 to detect the position of the operating member 511 while calibrating the detection data. When the difference between the detection data and the calibration data exceeds a preset value, it indicates an anomaly in the detection data. The controller 72 controls the travel motor 42 to stop or enter a speed-limited mode. This anomaly detection method is robust and reliable. The proportional relationship that needs to be explained includes the ratio of the first output signal to the second output signal, or the relative magnitude of the first output signal to the second output signal, or the difference between the first output signal and the second output signal.

[0060] like Figure 14 As shown, the control mechanism 70 of the manned lawnmower 200a includes an operation circuit board 54. A first sensor 521 and a second sensor 531 are respectively mounted on both sides of the operation circuit board 54 and arranged opposite to each other. In this embodiment, the operation circuit board 54 includes a printed circuit board (PCB) and a flexible printed circuit board (FPC). The first sensor 521 includes a non-contact sensor, such as a Hall sensor. A first magnet 511c, which is detected by the magnetic field sensor, is disposed on the operating member 511. The first sensor 521 detects changes in the magnetic field of the first magnet 511c and sends a first output signal representing the position of the operating member 511 to the controller 72. The second sensor 531 includes a non-contact sensor, such as a Hall sensor. The second sensor 531 detects changes in the magnetic field of the first magnet 511c. By detecting changes in the magnetic field of the first magnet 511c, the second sensor 531 sends a second output signal representing the position of the operating member 511 to the controller 72. The controller 72 determines that the first sensor 521 of the position detection device 52 has detected an abnormality by determining that the ratio between the first output signal and the second output signal exceeds a preset range. The controller 72 then controls the walking motor 42 to stop or operate at a limited speed. Other exemplary sensors include potentiometers.

[0061] like Figure 15As shown, in this embodiment, the controller 72 includes a first regulated voltage source 54a that supplies power to the first sensor 521 and a second regulated voltage source 54b that supplies power to the second sensor 531. The first regulated voltage source 54a and the second regulated voltage source 54b are isolated from each other and from the rest of the controller 72 circuitry. By using redundant regulated voltage sources, if one of the first regulated voltage source 54a and the second regulated voltage source 54b fails, the manned lawnmower 200a will still be able to operate in a safe mode.

[0062] In this embodiment, the controller 72 includes multiple control chips, meaning that the controller 72 employs dual-MCU or multi-MCU control. For example, the controller 72 includes a first controller 72a that controls the walking motor 42, a third controller 72c that calculates the ratio between the first and second output signals and sends the result to the first controller 72a, and a fourth controller 72d that adjusts the voltage source. It is understood that the multiple controllers 72 can be mounted on a single circuit board or on multiple circuit boards.

[0063] In this embodiment, the controller 72 controlling the walking motor 42 to stop includes: the controller 72 directly sending a control signal to the walking motor 42, causing the walking motor 42 to stop through the switching state of the drive circuit 73b. It also includes the controller 72 controlling the brake motor 465 and the brake mechanism 46, braking the walking motor 42 through the brake mechanism 46. Alternatively, the parking brake mechanism 44 can be used to brake the output shaft 423 of the walking motor 42, thereby braking the walking motor 42.

[0064] In speed-limited mode, controller 72 is configured to limit the speed of travel motor 42 to less than or equal to the first speed when the target speed indicated by operating element 511 is greater than the first speed. This ensures that travel motor 42 travels at a low speed for operations such as returning home or entering a maintenance station.

[0065] In this embodiment, the human-machine interaction mechanism 60 is used to output an alarm signal to the user when the ratio of the first output signal and the second output signal exceeds a preset range. Depending on the human-machine interaction mechanism 60, the alarm signal includes audible prompts (including buzzers, warning sounds, or voice prompts), photoelectric prompts (including flashing and special color changes), and markings and special code displays.

[0066] In this embodiment, the right operating member 511R and the left operating member 511L have the same structure and control method, ensuring the robustness of the detection data of the operating mechanism 50.

[0067] like Figure 16As shown, this application also discloses an outdoor walking device 100, including a working attachment for performing the functions of the outdoor walking device 100. The outdoor walking device 100 also includes a position detection device 52. The position detection device 52 includes a first sensor 521 for detecting the position of an operating component 511. The first sensor 521 emits a first output signal. It also includes a detection calibration device 53 for detecting the position of the operating component 511 and emitting a second output signal. A controller 72 is configured to control the operation of the walking motor 42 based on the first output signal to change the speed or direction of the outdoor walking device 100; and to output an alarm signal to the user when at least one of the following occurs: an abnormal first output signal, an abnormal second output signal, or an abnormal ratio between the first and second output signals. This allows the user to promptly detect abnormalities in the detection components or detection data and take appropriate action, ensuring driving safety. In this embodiment, the working attachment includes a mowing assembly 80, which includes a mowing blade 81 and a mowing motor 82 for driving the mowing blade 81. Figure 3 As shown, in some embodiments, the working attachments include a snow-shoveling mechanism 80d, and the outdoor walking device 100 is a snow sweeper 100d.

[0068] In this embodiment, when the controller 72 determines that either the first sensor 521 or the second sensor 531 emits an abnormal signal, the other sensor takes over the operation of the sensor that malfunctioned and emits the detection result in the form of a signal.

[0069] like Figure 17 The diagram illustrates the structure of the mowing assembly 80 and its control method. This application discloses an electric lawnmower 200. The electric lawnmower 200 disclosed in this application includes a push-type or walk-behind lawnmower, a manned lawnmower 200a, and a mowing robot.

[0070] like Figures 17 to 19As shown, the electric lawnmower 200 includes a mowing assembly 80, including mowing blades 81 and a mowing motor 82 for driving the mowing blades 81. A power supply mechanism 20 supplies power to at least the mowing motor 82. In this embodiment, the mowing motor 82 is configured as an electric motor, such as a brushless motor. In this embodiment, an internal rotor brushless motor is used as an example; the term "mowing motor" will be used hereinafter to refer to the mowing motor 82, but this should not be construed as a limitation of this application. The mowing motor 82 is a three-phase brushless motor, including a stator 826 and a rotor 827. The stator 826 includes a stator core 826a and coil windings 826b. The mowing motor 82 includes electronically commutated three-phase stator windings U, V, and W. In some embodiments, the three-phase stator windings U, V, and W are connected in a star configuration; in other embodiments, they are connected in a delta configuration. However, it must be understood that other types of brushless motors are also within the scope of this disclosure. Brushless motors may include fewer or more than three phases.

[0071] The electric lawnmower 200 also includes a control mechanism 70, which includes a drive circuit and a controller. For ease of distinction, the part controlling the lawnmower motor 82 is referred to as the lawnmower drive circuit 73c and the lawnmower controller 72e. The lawnmower controller 72e is used to control the operation of the lawnmower motor 82. The lawnmower drive circuit 73c is connected to the lawnmower controller 72e. The lawnmower drive circuit 73c is used to supply power to the lawnmower motor 82 from the power supply mechanism 20. For example, the lawnmower drive circuit 73c includes multiple power transistors (e.g., Q1, Q2, Q3, Q4, Q5, and Q6). The power transistors change their on / off state according to the control signal output by the lawnmower controller 72e, thereby changing the voltage and / or current state applied to the lawnmower motor 82 by the power supply mechanism 20 (battery pack 21) to control the operation of the lawnmower motor 82. The lawnmower drive circuit 73c can be a three-phase bridge driver circuit comprising six controllable semiconductor power devices (such as field-effect transistors (FETs), bipolar junction transistors (BJTs), insulated-gate bipolar transistors (IGBTs), etc.). It is understood that the aforementioned switching elements can also be any other type of solid-state switch, such as IGBTs, BJTs, etc.

[0072] In this embodiment, the lawn mower controller 72e is configured to: receive at least one signal related to the phase current of the lawn mower motor 82; determine the angular position of the rotor 827 based on the phase current of the lawn mower motor 82; and output a drive signal based on the angular position of the rotor 827 to apply to the lawn mower drive circuit 73c to control the operation of the lawn mower motor 82. During the startup phase of the lawn mower motor 82, the controller 72 obtains the initial sector among multiple sector positions of the rotor 827 based on a pulse injection method, and obtains the rotor 827 position in the initial sector based on a high-frequency signal injection method to control the startup state of the lawn mower motor 82. The high-frequency signal includes a periodic signal, wherein the amplitudes of the positive half-cycle and the negative half-cycle of the periodic signal are different.

[0073] Optionally, a current detection component 84e is also included to detect the phase current of the stator winding 421 in the motor in real time. The lawnmower controller 72e can also calculate the motor speed based on the phase current; for example, the motor speed can be estimated based on relevant parameters of the phase current, such as frequency.

[0074] During the mowing operation of the electric lawnmower 200, the process from the shutdown state to the point where the lawnmower motor 82 reaches the required speed is the start-up phase. The shutdown state of the lawnmower motor 82 is defined as when its speed is zero or nearly zero. The required speed of the lawnmower motor 82 is either a preset speed for mowing operations or a speed set by the user. In some embodiments, the speed of the lawnmower motor 82 is a set value, meaning the operator cannot set or select the speed or speed range of the lawnmower motor 82. The required speed of the lawnmower motor 82 is the aforementioned set value. Optionally, the required speed of the lawnmower motor 82 is its rated speed to ensure efficient and safe operation. In some embodiments, the speed of the lawnmower motor 82 is a speed or speed range that the user can set. For example, the lawnmower motor 82 includes a high-speed gear and a low-speed gear. The high-speed gear corresponds to a first rated speed under a first load, and the low-speed gear corresponds to a second rated speed under a second load.

[0075] In this embodiment, taking the rotational speed of the lawnmower motor 82 as a set value as an example, the starting phase of the lawnmower motor 82 is the process from the stopped state to the lawnmower motor 82 reaching its rated speed. If the rotational speed of the lawnmower motor 82 is directly increased to the rated speed during the starting phase, and if the amount of grass to be mowed is large, causing the starting load of the lawnmower motor 82 to exceed the preset value, it may easily lead to excessive current in the lawnmower motor 82, and may also cause the lawnmower motor 82 to fail to start.

[0076] The startup phase also includes an initial phase and an acceleration phase. In the initial phase, the lawnmower motor 82 maintains a low speed to induce rotation along with the mowing element. In this embodiment, the lawnmower motor 82 employs sensorless control, and the mowing controller 72e detects the angular position of the rotor 827 based on at least one signal related to the phase current of the lawnmower motor 82. In this embodiment, the lawnmower motor 82 is a three-phase brushless motor, and the mowing drive circuit 73c is a three-phase inverter bridge driver circuit, wherein the three-phase inverter bridge circuit includes three high-side FETs and three low-side FETs. The gates of the high-side FETs are driven by drive signals UH, VH, and WH, and the gates of the low-side FETs are driven by drive signals UL, VL, and WL. The drains of the high-side FETs are coupled to the sources of the low-side FETs to output power signals PU, PV, and PW for driving the lawnmower motor 82. Figure 20 As shown, the lawnmower motor 82 is divided into six sectors in the circumferential direction of the stator 826 at π / 3 electrical degrees. That is to say, the motor needs to perform a commutation operation every π / 3 electrical degrees. Or, the 360-degree rotation of the rotor 827 of the lawnmower motor 82 can be divided into 6 sectors, each sector being 60 degrees. In each sector, only one high-side switch and one low-side switch are active.

[0077] In this embodiment, during the initial stage of the startup phase, the mowing controller 72e obtains the initial sector among multiple sector positions of the rotor 827 based on a pulse injection method. Optionally, during Initial Position Detection (IPD), the mowing controller 72e sequentially injects a series of voltage pulses into each sector of the motor. After each voltage pulse injection, the mowing controller 72e measures the current through a preset resistor. The sector corresponding to the position of the rotor 827 generates the largest induced current in response to the voltage pulse. Therefore, the sector corresponding to the larger current measurement is identified by the mowing controller 72e as the initial position of the rotor 827. Exemplarily, the width of the preset voltage pulse and the setting position of the preset resistor are preset according to different motor rated parameters, and vary depending on the embodiment; no specific limitation is made here.

[0078] After determining the initial sector of the rotor 827 of the lawnmower motor 82, the lawnmower controller 72e obtains the angular position of the rotor 827 in the initial sector based on a high-frequency signal injection method. The high-frequency signal includes a periodic signal, with different amplitudes for the positive and negative half-cycles. This increases the saliency ratio of the rotor 827 of the lawnmower motor 82. During the high-frequency signal injection process, a DC bias is injected during either the positive or negative half-cycle of the phase current periodic signal, ensuring that the amplitude of the injected DC bias signal during either the positive or negative half-cycle is greater than or equal to 10% and less than or equal to 20% of the bus voltage. This increases the ratio of the quadrature-axis component iq to the direct-axis component id of the rotor 827 current.

[0079] In this embodiment, the high-frequency signal injection method can accurately obtain the position information of the rotor 827 when the motor is at low speed or stationary. The lawnmower controller 72e outputs a high-frequency electrical signal to be applied to the three-phase stator 421 winding of the motor, and obtains the response signal output by the stator 421 winding based on the high-frequency electrical signal. The so-called response signal can be a high-frequency phase current signal with a high-frequency amplitude. Optionally, the controller 72 can estimate the position of the rotor 827 based on the relative relationship between the response signal and the preset rotor 827 position. For example, the controller 72 can estimate the position of the rotor 827 based on the relative relationship between the high-frequency amplitude of the response signal and the preset rotor 827 position. It should be noted that since the component iq of the high-frequency response signal on the quadrature axis is correlated with the rotor 827 position error, when the amplitude of the high-frequency response signal converges to zero, the corresponding preset rotor 827 position will also converge to obtain the true rotor 827 position. In this application, the direction of the rotor 827 position is defined as the direct axis (d-axis), and the direction perpendicular to the direct axis is defined as the quadrature axis (q-axis).

[0080] like Figure 21 As shown, in this embodiment, the lawnmower motor 82 is controlled using field-oriented control (FOC) mode. The FOC vector control mode includes a current loop and a speed loop. The lawnmower controller is configured to obtain the three-phase currents (e.g., Iu, Iv, Iw) of the lawnmower motor 82 in a three-phase stationary coordinate system (the current vectors of two phases of the three-phase coil can be sampled first, and the last phase can be calculated using Kirchhoff's current law). After Clark transformation, two orthogonal time-varying current vectors I_α and I_β are obtained. After Park transformation, two-phase DC currents, the q-axis current iq and the d-axis current id, are obtained, with the q-axis current iq and d-axis current id perpendicular to each other. The target q-axis current iq is obtained based on the actual current of the lawnmower motor 82 through decoupling. * and d-axis target current id *The q-axis current iq and the target q-axis current iq are controlled using a PI control method. * The deviation between them, and the d-axis current id and the d-axis target current id * The deviation between the two phases is adjusted to output voltage vectors, namely the target voltage Uq on the q-axis and the target voltage Ud on the d-axis. Further, the obtained voltage vectors are inversely transformed to a two-phase stationary coordinate system using Park transformation to obtain two-phase DC voltages Uu and Uv. Then, using space vector pulse width modulation (PWM) technology, the two-phase AC voltages are converted into three-phase AC voltages (Uu, Uv, and Uw). These three-phase AC voltages are the target voltages applied to the mowing motor 82. The controller can generate PWM signals based on the acquired target voltages to control the on / off state of the switching elements in the drive circuit, causing the mowing motor 82 to operate according to the set control mode. In this embodiment, a PI controller is integrated. The PI controller has a proportional term P and an integral term I, and the proportional term P of the PI controller can be adjusted according to the set control mode. In the speed loop, a speed and position detection module is used to obtain the speed feedback value ω and the rotor angle feedback θ.

[0081] like Figure 21 As shown, a high-frequency square wave voltage signal is injected onto the d-axis of the synchronously rotating dq coordinate system. Optionally, the frequency of the injected high-frequency square wave signal is usually an integer multiple of the pulse width modulation (PWM) switching frequency. For example, a positive square wave voltage is injected during the positive half-cycle of the d-axis, and a negative square wave voltage is injected during the negative half-cycle. The amplitude of the injected square wave voltage signal is greater than or equal to 7% and less than or equal to 15% of the bus voltage. Since the position of rotor 827 is observed based on the salient pole characteristics when the motor is at low speed or stationary, it is necessary to amplify the salient pole characteristic of the motor to improve the accuracy of rotor 827 position observation. The air gap of a salient pole motor is non-uniform, that is, the effective air gap of the direct axis (d-axis) and the quadrature axis (q-axis) is different. The influence of the quadrature-direct axis armature reaction reactance on motor performance is called the salient pole effect. The salient pole ratio is commonly expressed as the ratio of the quadrature axis inductance Lq to the direct axis inductance Ld. In this embodiment, during the high-frequency signal injection process, a DC bias is injected during the positive or negative half-cycle of the phase current periodic signal. This ensures that the amplitude of the signal during the positive or negative half-cycle of the injected DC bias voltage is greater than or equal to 10% and less than or equal to 20% of the bus voltage, thereby enhancing the saliency effect of the motor and increasing the saliency ratio. Optionally, the amplitude of the injected DC bias signal is greater than or equal to 0 and less than or equal to 10% of the bus voltage. In this embodiment, the amplitude of the positive half-cycle of the periodic signal is set to the sum of the amplitude of the negative half-cycle and the preset DC bias.

[0082] In this embodiment, the controller 72 is further configured to calculate the position and speed of the rotor 827 of the mowing motor 82 using a flux linkage observer method. When the speed is greater than or equal to a speed threshold and the start-up time is greater than or equal to a time threshold, the controller controls the mowing motor 82 to commutate to enter the acceleration phase based on the rotor 827 position estimated by the flux linkage observer method. The mowing controller 72e obtains the angular position of the rotor 827 in the initial sector using a high-frequency signal injection method, and simultaneously estimates the rotor 827 position and speed using the flux linkage observer method. Based on the rotor 827 speed and time, it determines whether the motor can enter the acceleration phase to further increase the speed to or near the rated speed. In this embodiment, the speed and position detection module uses a flux linkage observer method to calculate the rotor 827 angle feedback θ and speed feedback value ω of the mowing motor 82.

[0083] Optionally, the speed threshold is greater than or equal to 9% of the rated speed. Optionally, the speed threshold is greater than or equal to 10% of the rated speed. Optionally, the speed threshold is greater than or equal to 11% of the rated speed. Optionally, the speed threshold is greater than or equal to 12% of the rated speed. Optionally, the speed threshold is greater than or equal to 13% of the rated speed. Optionally, the speed threshold is greater than or equal to 14% of the rated speed. Optionally, the speed threshold is greater than or equal to 15% of the rated speed. Optionally, the time threshold is greater than or equal to 500ms. Optionally, the time threshold is greater than or equal to 400ms. Optionally, the time threshold is greater than or equal to 300ms. Optionally, the time threshold is greater than or equal to 200ms. Optionally, the time threshold is greater than or equal to 100ms. Optionally, the time threshold is greater than or equal to 50ms. In this embodiment, during the start-up phase of the mowing motor 82, the lawn mower controller 72e uses a flux linkage observer to calculate the position and speed of the rotor 827 of the mowing motor 82. When the speed is greater than or equal to 9% of the rated speed and the start-up time is greater than or equal to 500ms, the controller controls the commutation of the mowing motor 82 based on the rotor 827 position estimated by the flux linkage observer to enter the acceleration phase, thereby accelerating the speed of the mowing motor 82 to the rated speed or close to the rated speed.

[0084] Optionally, the controller 72 is further configured to control the mower motor 82 to enter a stall protection mode when the speed of the mower motor 82 calculated using the flux linkage observer method is less than or equal to 0.5% of the rated speed and the start-up time is greater than or equal to 2.5 seconds. Optionally, the controller 72 is further configured to control the mower motor 82 to enter a stall protection mode when the speed of the mower motor 82 calculated using the flux linkage observer method is less than or equal to 3% of the rated speed and the start-up time is greater than or equal to 5 seconds. When the amount of grass to be mowed is relatively large, causing the starting load of the mower motor 82 to exceed a preset value, the mower motor 82 may fail to reach the preset speed within the preset start-up time. In this case, the controller 72 determines that the load on the mower motor 82 is too high. Forcibly accelerating the mower motor 82 at this time would cause excessive current in the mower motor 82, damaging it. To protect the mowing motor 82, a flux linkage observer is used to determine if the motor's speed and start-up time meet the conditions for stalling. In this case, the mowing controller 72e controls the mowing motor 82 to enter a stall protection mode. Optionally, the stall protection mode includes the mowing controller 72e controlling the mowing motor 82 to slow down or stop, and the mowing controller 72e controlling the mowing motor 82 to intermittently stop and start.

[0085] Optionally, based on the rotational speed and time of the rotor 827, after determining that the motor can enter the acceleration phase to further increase the rotational speed to or near the rated speed, the lawn mower controller 72e switches to a high-frequency signal injection method based on the rotational speed change of the lawn mower motor 82 to obtain the position of the rotor 827 and then controls the operation of the lawn mower motor 82 according to the position of the rotor 827.

[0086] like Figure 22 As shown, based on the same concept, this application also provides a control method for an electric lawnmower 200. The method includes the following steps: S801: The lawnmower motor is on.

[0087] S802: The initial sector is obtained from the multiple sector positions of the rotor based on the pulse injection method.

[0088] S803: The rotor position in the initial sector is obtained based on the high-frequency signal injection method.

[0089] High-frequency signals include periodic signals, and the amplitudes of the positive half-cycle and the negative half-cycle of the periodic signal are different. During the high-frequency signal injection process, a DC bias is injected into the positive half-cycle or the negative half-cycle of the phase current periodic signal so that the amplitude of the signal in the positive or negative half-cycle of the injected DC bias is greater than or equal to 10% of the bus voltage and less than or equal to 20% of the bus voltage.

[0090] S804: Controls the start of the lawnmower motor based on the rotor position.

[0091] like Figure 23 As shown, based on the same concept, this application also provides another control method for an electric lawnmower 200. The method includes the following steps: S901: The lawnmower motor is turned on, entering the initial stage of the startup phase.

[0092] During the mowing operation of the electric lawnmower 200, the process from the time the mowing motor 82 is stopped until it reaches the required speed is called the start-up phase. The stopping state of the mowing motor 82 is defined as when its speed is zero or nearly zero. The start-up phase also includes an initial phase and an acceleration phase. In the initial phase, the mowing motor 82 maintains a low speed to induce rotation along with the mowing components.

[0093] S902: Based on the rated parameters of different motors, preset the width of the voltage pulse and the preset position of the resistor.

[0094] S903: Inject a high-frequency square wave voltage signal on the d-axis. Inject a DC bias during the positive half-cycle or negative half-cycle of the periodic signal. The amplitude of the DC bias signal is greater than or equal to 0 and less than or equal to 10% of the bus voltage.

[0095] The lawnmower controller 72e uses a pulse injection method to determine the initial sector among multiple sector positions of the rotor 827. Optionally, during Initial Position Detection (IPD), the lawnmower controller 72e sequentially injects a series of voltage pulses into each sector of the motor. After each voltage pulse injection, the lawnmower controller 72e measures the current through a preset resistor. The sector corresponding to the rotor 827 position generates the largest induced current in response to the voltage pulse. Therefore, the sector corresponding to the larger current measurement is identified by the lawnmower controller 72e as the initial position of the rotor 827.

[0096] Using a high-frequency signal injection method, the position information of rotor 827 can be accurately obtained when the motor is at low speed or stationary. During the high-frequency signal injection process, a DC bias is injected during the positive or negative half-cycle of the phase current cycle signal. This ensures that the amplitude of the injected DC bias voltage signal during the positive or negative half-cycle is greater than or equal to 10% and less than or equal to 20% of the bus voltage, thereby enhancing the salient pole effect of the motor and increasing the salient pole ratio. Optionally, the amplitude of the injected DC bias signal is greater than or equal to 0 and less than or equal to 10% of the bus voltage.

[0097] S904: The rotor position and rotor speed estimated using the flux linkage observer method.

[0098] The lawnmower controller 72e obtains the angular position of rotor 827 in the initial sector based on the high-frequency signal injection method. At the same time, it uses the magnetic flux observer method to estimate the position and speed of rotor 827. Based on the speed and time of rotor 827, it determines whether the motor can enter the acceleration phase to further increase the speed to the rated speed or close to the rated speed.

[0099] S905: The engine speed is less than or equal to 0.5% of the rated speed and the start-up time is greater than or equal to 2.5 seconds. If yes, proceed to S906; otherwise, proceed to S907.

[0100] S906: Stall protection mode.

[0101] The stall protection mode includes the lawn mower controller 72e controlling the lawn mower motor 82 to slow down or stop, and the lawn mower controller 72e controlling the lawn mower motor 82 to intermittently stop and start.

[0102] S907: The engine speed is less than or equal to 3% of the rated speed and the start-up time is greater than or equal to 5 seconds. If yes, proceed to S906; otherwise, proceed to S908.

[0103] When the amount of grass to be mowed is large, causing the starting load of the mowing motor 82 to exceed a preset value, the mowing motor 82 may fail to reach the preset speed within the preset starting time. In this case, the controller 72 determines that the load on the mowing motor 82 is too high. Forcing the mowing motor 82 to accelerate under these conditions would cause excessive current and damage it. To protect the mowing motor 82, a flux linkage observer is used. Once the speed and starting time of the mowing motor 82 meet the conditions for motor stall, the mowing controller 72e controls the mowing motor 82 to enter a stall protection mode.

[0104] S908: The engine speed is greater than or equal to 9% of the rated speed and the start-up time is greater than or equal to 500ms. If yes, then execute S910; otherwise, execute S909.

[0105] S909: Timer reset.

[0106] S910: The rotor position and rotor speed are estimated using the flux linkage observer method.

[0107] The position of rotor 827, estimated using the flux linkage observer method, controls the commutation of lawnmower motor 82 to enter the acceleration phase, thereby accelerating the speed of lawnmower motor 82 to or near the rated speed.

[0108] S911: The engine speed is less than or equal to 10% of the rated speed and the start-up time is greater than or equal to 100ms. If yes, then execute S906; otherwise, execute S912.

[0109] S912: The engine speed is less than or equal to 12% of the rated speed and the start-up time is greater than or equal to 200ms. If yes, then execute S909; otherwise, execute S904.

[0110] In this embodiment, as mentioned above, the lawn mower controller 72e utilizes field-oriented control (FOC) for the lawn mower motor 82. The FOC vector control mode includes a current loop and a speed loop. Exemplarily, the current loop includes a bus current loop and a phase current loop. The loops are closed-loop feedback.

[0111] In this embodiment, once the speed of the mowing motor 82 reaches or is at least close to the rated speed, it is determined that the mowing motor 82 has completed its startup and entered the operating state. Optionally, the startup completion and operating state of the mowing motor 82 can be determined based on a combination of the operating time and speed of the mowing motor 82. Optionally, the startup completion and operating state of the mowing motor 82 can be determined based on the output torque and related parameters of the mowing motor 82.

[0112] Once the lawnmower motor 82 has started, the lawnmower controller 72e determines that the load on the lawnmower motor 82 exceeds a preset load threshold based on the current loop exceeding a preset threshold, and the controller 72 enters the overcurrent protection program. In this embodiment, after the lawnmower controller 72e determines that the phase current and bus current of the lawnmower motor 82 exceed the phase current threshold and bus current threshold respectively, the lawnmower controller 72e controls the three-phase short-circuit braking of the lawnmower motor 82. Optionally, when the current in the phase current is greater than or equal to the hardware overcurrent threshold and the time exceeds 4μs, the lawnmower controller 72e controls the three-phase short-circuit braking of the lawnmower motor 82. Optionally, when the current in the bus current is greater than or equal to the software overcurrent threshold and the time exceeds 3s, the lawnmower controller 72e controls the three-phase short-circuit braking of the lawnmower motor 82. Optionally, when the starting time of the mowing motor 82 is greater than or equal to 5 seconds and the speed is less than 3% of the rated speed, or when the starting time of the mowing motor 82 is greater than or equal to 2.5 seconds and the speed is less than 0.5% of the rated speed, the mowing controller 72e controls the three-phase short-circuit braking of the mowing motor 82.

[0113] like Figure 24As shown, a PTO switch 85 is provided on the power supply branch of the lawn mower controller 72e. The PTO switch 85 is a switch used to control the auxiliary power output device. The lawn mower controller 72e is configured to power on when the PTO switch 85 is turned on, applying a drive signal to the drive circuit 73c to control the operation of the lawn mower motor 82. The first terminal of the PTO switch 85 is electrically connected to the power supply mechanism 20 via a DC / DC voltage conversion module, and the second terminal of the PTO switch 85 is used to control the power supply Vp. The power supply mechanism 20 outputs VHM via a switching transistor to power the drive circuit 73c and the lawn mower controller 72e on the control board. By setting the PTO switch to control the power-on and start-up of the lawn mower controller 72e, there is no need to detect the switch signal of the control board.

[0114] In this embodiment, after the mower controller 72e determines that the phase current and bus current of the mower motor 82 exceed the phase current threshold and bus current threshold respectively, the mower controller 72e initiates the overcurrent protection program. The mower controller 72e controls the three-phase short-circuit braking of the mower motor 82 until the mower motor 82 stops, and the PTO is operated to the open position to exit the overcurrent protection program. Optionally, operating the speed control switch cannot exit the overcurrent protection state.

[0115] For example, when the phase current threshold is less than or equal to 203A, or when the phase current value is greater than the phase current threshold, the mowing controller 72e limits the output torque of the mowing motor 82, and the speed of the mowing motor 82 decreases. Optionally, when the mowing controller 72e determines that the load of the mowing motor 82 is greater than the output torque of the mower, the mowing controller 72e controls the mowing motor 82 to slow down; when the mowing controller 72e determines that the load of the mowing motor 82 is less than or equal to the output torque of the mower, the mowing controller 72e controls the mowing motor 82 to speed up.

[0116] For example, when the bus current exceeds the bus current threshold, the mower controller 72e actively reduces the target speed of the mower motor 82. The greater the bus current exceeds the bus current threshold, the lower the given target speed. When the bus current is less than or equal to the bus current threshold, the user-input target speed is maintained. By adding a bus current loop to the speed loop control strategy, the target speed of the mower motor 82 is jointly determined based on the bus current and the user input.

[0117] like Figures 25 to 26As shown, the lawnmower motor 82 includes a motor housing 821 and a cable 822. The motor housing 821 includes a motor housing body 821a and a motor housing cover 821d. A wiring harness hole 821g is formed on the motor to allow the cable 822 to pass through. In this embodiment, the motor housing body 821a includes a support portion 821e for accommodating the cable 822. The support portion 821e has an opening on the side where the cable 822 extends, facilitating mold manufacturing.

[0118] The support portion 821e is provided with a wire harness hole 821g, and the support portion 821e has a certain length along the axial direction of the wire harness outlet. A waterproof sleeve 825 is fitted onto the cable 822. For example, two waterproof sleeves 825 are provided on the cable 822 and respectively fit into both ends of the support portion 821e, that is, one waterproof sleeve 825 is provided on the side of the support portion 821e near the inside of the motor housing 821, and the other waterproof sleeve 825 is provided on the side of the support portion 821e near the outside. The outer periphery of the waterproof sleeve 825 is provided with a fitting structure that mates with the support portion 821e. Optionally, the outer periphery of the waterproof sleeve 825 is provided with a flange 8251, and the inner side of the support portion 821e is provided with a groove 821f at a relatively opposite position.

[0119] The motor housing 821a and the motor housing cover 821d are connected by fasteners or a fastening structure. The motor housing cover 821d is plate-shaped, and an opening is provided on one side of the motor housing 821a, which needs to be covered and sealed by the motor cover. A sealing groove 821c is provided circumferentially along the opening of the motor housing 821a, and an O-ring 824 is embedded in the sealing groove 821c. After the motor cover is pressed against the O-ring 824, the O-ring 824 fills the sealing groove 821c, achieving a waterproof seal between the motor cover and the motor housing 821a.

[0120] The O-ring 824 extends into the support portion 821e and extends between the two waterproof sleeves 825. To ensure waterproofing, waterproof sealant 828 is injected between the two waterproof sleeves 825. This multi-layer waterproofing design ensures the waterproofing effect of the lawnmower motor 82.

[0121] like Figure 27 As shown, another sealing method is used for the cable of the lawnmower motor 82. A cover plate 821h is provided on the opening of the support part 821e on the motor housing 821. The cover plate 821h is used to cover the opening, and the wire harness hole 821g is formed on the cover plate 821h. A sealing gasket 823 is provided between the cover plate 821h and the support part 821e.

[0122] In this embodiment, a bidirectional terminal assembly 831 is formed or connected to the cover plate 821h. The bidirectional terminal assembly 831 includes a male connector and a female connector. A sealed space is formed between the cover plate 821h and the sealing gasket 823 and the motor housing 821a. One end of the bidirectional terminal assembly 831 is located inside the motor housing 821a, and the other end is located on the outside, connecting to the lawnmower controller 72e. The connector of the bidirectional terminal assembly 831 inside the motor housing 821a is connected to the motor cable.

[0123] like Figures 28 to 29 The diagram illustrates another sealing method for the cable of the lawnmower motor 82. A cable harness hole 821g is provided on the support portion 821e of the motor housing 821 to allow external cables to pass through. A waterproof gland 841 is fitted onto the external cable, sealing the connection to the cable harness hole 821g. The external cable and the internal cable 822 are fixedly mounted on a terminal block 842, which is secured within the motor housing 821a by screws and located within its accommodating space. Terminal blocks 842 have terminals, and the external cable and internal cable 822 are secured to the terminals with nuts to complete the electrical connection.

[0124] like Figure 30 As shown, a waterproof and breathable valve 438 is provided on the motor housing cover 821d. Its specific structure is similar to the connection method of the travel motor 42, and will not be described in detail here. like Figure 17 As shown, in this embodiment, the mowing assembly 80 includes multiple mowing blades 81 and mowing motors 82 for driving the mowing blades 81 respectively; that is, multiple mowing motors 82 are also provided. In some embodiments, the multiple mowing motors 82 adopt the same structure. The multiple mowing motors 82 are circuit controlled by the same mowing controller 72e. In some embodiments, the multiple mowing motors 82 are each circuit controlled by an independent mowing controller 72e; that is, multiple MUCs are used and placed on different control circuit boards 71.

[0125] like Figure 31a , Figure 31b and Figure 33As shown, in some embodiments, the connectors of the power supply mechanism 20 include a first connector 22a and a second connector 22b with different external shapes. Specifically, the first connector 22a is configured to electrically connect one battery pack 21, and the second connector 22b is configured to electrically connect at least two battery packs 21. The external dimensions of the second connector 22b are larger than those of the first connector 22a. Thus, by providing connectors 22 with different external shapes for mounting the battery packs 21, the power requirements of different outdoor walking devices 100 can be met. For example, for a push lawnmower or snowplow 100d, the power supply mechanism 20 can use the first connector 22a to mount the battery pack. For an all-terrain vehicle 100c, multiple first connectors 22a with battery packs 21 mounted can be used, or one or more second connectors 22b with at least two battery packs 21 mounted can be used, or a combination of first connectors 22a and second connectors 22b can be used. In this way, by combining the power consumption needs of the outdoor walking device 100 with its own spatial characteristics, the connectors for installing the battery pack are reasonably selected and arranged, which improves the versatility of the power supply mechanism 20 among various power-consuming devices, thereby making the application scenarios of the power supply mechanism 20 wider and providing convenience for users.

[0126] In some embodiments, the connector 22 may be a battery compartment with a receiving space and a joint, or other type of structure for mounting the battery pack 21 to the manned lawnmower 200a. Hereinafter, the battery compartment 22 is used in place of the connector 22; however, the connector may also have other external features, such as a base.

[0127] The battery pack 21 as a whole meets the IPX7 waterproof and dustproof requirements, while the battery compartment meets the IPX5 waterproof requirements. The average discharge current of the battery pack 21 is greater than or equal to 30A, for example, 30A, 35A, 40A, etc. Optionally, the rated output current of the battery pack 21 can be greater than or equal to 120A or the instantaneous peak current can be approximately 350A.

[0128] In this embodiment, the weight of the battery pack 21 is greater than or equal to 9 kg. In one embodiment, the weight of the battery pack 21 is greater than or equal to 10 kg, or greater than or equal to 11 kg, or greater than or equal to 12 kg, or greater than or equal to 13 kg, or greater than or equal to 14 kg, or greater than or equal to 15 kg, for example, the weight of the battery pack 21 is 9 kg, 10 kg, or 15 kg, etc. The nominal voltage of the battery pack 21 is approximately 56 V, for example, it can be 54 V or 58 V, etc. In one embodiment, the nominal voltage of the battery pack 21 is greater than or equal to 56 V, or the nominal voltage of the battery pack 21 is greater than or equal to 50 V, or the nominal voltage of the battery pack 21 is greater than or equal to 48 V, or the nominal voltage of the battery pack 21 is greater than or equal to 40 V. The capacity of the battery pack 21 is greater than or equal to 20 Ah. In one embodiment, the capacity of the battery pack 21 is greater than or equal to 30 Ah, or the capacity of the battery pack 21 is greater than or equal to 40 Ah, or the capacity of the battery pack 21 is greater than or equal to 50 Ah. For example, it can be 20Ah, 30Ah, 40Ah, 50Ah, etc. The capacity-to-weight ratio of the battery pack 21 is greater than or equal to 2Ah / kg, for example, 2Ah / kg, 4Ah / kg, 5Ah / kg, etc. Optionally, the energy of the battery pack 21 is greater than or equal to 2kW·h. In one embodiment, the energy of the battery pack 21 is greater than or equal to 3kW·h, or greater than or equal to 4kW·h, or greater than or equal to 5kW·h. For example, the energy of the battery pack 21 can be 2kW·h, 3kW·h, 4kW·h, 5kW·h, etc. In some embodiments, the battery pack 21 disclosed in this application may include lithium iron phosphate cells. In some embodiments, the battery pack 21 may also be a supercapacitor, also known as an electrochemical capacitor.

[0129] In some embodiments, see Figure 32 As shown, the second battery compartment 22b can also accommodate a third battery pack 21c, which is different from the battery pack 21. Specifically, two third battery packs 21c are installed to and electrically connected to the adapter 21d, and the adapter 21d is electrically connected to the joint of the second battery compartment 22b. The energy of the third battery pack 21c is greater than or equal to 0.1 kWh and less than 2 kWh. Optionally, the third battery pack 21c is a battery pack 21 with an energy greater than or equal to 0.1 kWh. In some embodiments, the third battery pack 21c is a battery pack 21 with an energy greater than or equal to 0.4 kWh. In some embodiments, the third battery pack 21c is a battery pack 21 with an energy greater than or equal to 0.6 kWh. In this embodiment, the third battery pack 21c is a lithium-ion battery cell, but nickel-cadmium batteries, graphene, and other materials can also be used to achieve different combinations of battery characteristics.

[0130] See also Figure 33As shown, the power supply mechanism 20 also includes a power management module 23. The power management module 23 includes a housing 231. All signal interfaces 232 and high-current interfaces 233 are directly integrated into the housing 231, eliminating the need for additional wiring harnesses and ensuring that the power management module 23 achieves an IPX5 waterproof rating. Specifically, the high-current interface 232 has wire terminal caps added to its wire ends and waterproof rubber sleeves added to its terminals.

[0131] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. An electric lawnmower, comprising: A brushless motor is used to drive lawn mowing blades or wheels; the brushless motor includes a stator and a rotor with multiple windings. A drive circuit is used to supply power from the power supply mechanism to the brushless motor; and The controller is configured to receive at least one signal related to the phase current of the brushless motor, detect the angular position of the rotor based on the phase current of the brushless motor, and output a drive signal to the drive circuit based on the angular position of the rotor to control the operation of the brushless motor. During the start-up phase of the brushless motor, the controller is configured to: The initial sector among the multiple sector positions of the rotor is obtained based on the pulse injection method; as well as The rotor position in the initial sector is obtained using a high-frequency signal injection method to control the start-up of the brushless motor; The high-frequency signal includes a periodic signal, wherein the amplitudes of the positive half-cycle and the negative half-cycle of the periodic signal are different.

2. The electric lawnmower according to claim 1, characterized in that, During the start-up phase of the brushless motor, the controller uses a flux linkage observer to calculate the rotor position and speed of the brushless motor. When the speed is greater than or equal to a speed threshold and the start-up time is greater than or equal to a time threshold, the controller uses the rotor position estimated by the flux linkage observer to control the brushless motor to commutate and enter the acceleration phase.

3. The electric lawnmower according to claim 2, characterized in that, The speed threshold is greater than or equal to 9% of the rated speed.

4. The electric lawnmower according to claim 2, characterized in that, The time threshold is greater than or equal to 500ms.

5. The electric lawnmower according to claim 2, characterized in that, During the startup phase, the controller is also configured to calculate the speed of the brushless motor using a flux linkage observer method, and to control the brushless motor to enter a stall protection mode when the speed of the brushless motor is less than or equal to 0.5% of the rated speed and the startup time is greater than or equal to 2.5s.

6. The electric lawnmower according to claim 2, characterized in that, During the startup phase, the controller is also configured to calculate the speed of the brushless motor using a flux linkage observer method, and to control the brushless motor to enter a stall protection mode when the speed of the brushless motor is less than or equal to 3% of the rated speed and the startup time is greater than or equal to 5 seconds.

7. The electric lawnmower according to claim 1, characterized in that, The amplitude of the positive half-cycle is set to the sum of the amplitude of the negative half-cycle and the preset DC bias.

8. The electric lawnmower according to claim 1, characterized in that, The electric lawnmowers include push lawnmowers, lawnmower robots, and manned lawnmowers.

9. An electric lawnmower, comprising: A brushless motor for driving lawn mowing blades or drive wheels; the brushless motor includes a stator and a rotor having multiple windings; A drive circuit is used to supply power from the power supply mechanism to the brushless motor; and The controller is configured to receive at least one signal related to the phase current of the brushless motor, detect the angular position of the rotor based on the phase current of the brushless motor, and output a drive signal to the drive circuit based on the angular position of the rotor to control the operation of the motor. During the start-up phase of the brushless motor, the controller is configured to: The initial sector among the multiple sector positions of the rotor is obtained based on the pulse injection method; as well as The rotor position in the initial sector is obtained using a high-frequency signal injection method to control the start-up of the brushless motor; the high-frequency signal includes a periodic signal. During the high-frequency signal injection process, a DC bias is injected during the positive half-cycle or negative half-cycle of the phase current periodic signal, so that the amplitude of the signal during the positive or negative half-cycle of the injected DC bias is greater than or equal to 10% of the bus voltage and less than or equal to 20% of the bus voltage.

10. The electric lawnmower according to claim 9, characterized in that, The amplitude of the positive half-cycle of the periodic signal is set to the sum of the amplitude of the negative half-cycle and the preset DC bias.

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