A method, components, apparatuses, and devices for starting an ec motor
By determining the position and speed of the EC motor rotor through discrete signal injection and back electromotive force, the problem of start-up delay in traditional EC motors is solved, achieving a high-efficiency and low-cost start-up process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANDREAS STIHL AG & CO KG
- Filing Date
- 2025-12-10
- Publication Date
- 2026-06-23
AI Technical Summary
Traditional EC motors require determining the initial position of the rotor during startup, resulting in response delays and time consumption. This is especially inconvenient when high starting torque is required, and the frequent use of sensors increases costs and maintenance expenses.
The rotor's position when stationary is determined by injecting discrete signals, the rotor is accelerated by a controlled rotating field, and the speed and position are determined by back electromotive force. The system then switches to a closed-loop operation mode, avoiding the traditional rotor alignment process.
It achieves high starting torque with no response delay, reduces the use of sensors, lowers costs and maintenance expenses, and improves starting efficiency and comfort.
Smart Images
Figure CN122268196A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for starting an EC motor and a component comprising an EC motor and a control device, wherein the control device is configured to perform the method. The invention also relates to an apparatus and device, each comprising the aforementioned component. Background Technology
[0002] Electric motor-driven equipment, particularly gardening equipment, devices for landscape maintenance or road maintenance, and agricultural or forestry equipment, typically requires high starting torque to drive the equipment used with it.
[0003] In traditional methods, starting a motor that requires a large starting torque (especially an EC motor) usually requires the use of special sensing systems such as Hall sensors to determine the initial position of the rotor, and then moving the rotor to a specified starting position in order to start acceleration from that starting position.
[0004] However, the rotor typically needs to be unloaded during initial positioning and alignment, which can impose certain limitations. Furthermore, the rotor alignment process before motor startup is relatively time-consuming, resulting in a response delay between the issuance of a motor power request (e.g., by the operator of the motor-driven equipment) and the provision of the required motor power. This delay can be uncomfortable for the operator. Summary of the Invention
[0005] According to a first aspect, the present invention provides a method for starting an EC motor, the motor having a stator and a rotor, the method comprising the following steps: a) Determine the first position of the rotor when it is stationary by injecting discrete signals; b) Achieving rotor acceleration through a controlled rotating field; c) Determine the rotor speed based on the back electromotive force (EMF) after reaching the predetermined rotating field frequency in step b); d) Compare the rotational speed measured in step c) with the first predetermined rotational speed value; and e) If the rotational speed measured in step c) is greater than the first predetermined rotational speed value: determine the second position of the rotor based on the back electromotive force, and switch to closed-loop operation mode based on the back electromotive force.
[0006] Therefore, this invention is based on a surprising discovery: by injecting discrete signals, the rotor position information required for proper energization of the motor coils can be determined particularly simply and reliably. Thus, it is no longer necessary to move the motor to a predetermined starting position. Instead, the rotor can accelerate directly from the initial (first) position by activating the coils associated with the first position.
[0007] Furthermore, the proposed method effectively eliminates response delays previously caused by rotor alignment. Additionally, the rotor does not need to be unloaded during startup. Therefore, even under conditions that traditionally require additional measures, the proposed method allows the motor to be easily started without auxiliary tools. For example, the proposed method can also be used to start the motor of gardening equipment where the motor-driven equipment has become stuck due to previous use, preventing the motor from running unloaded.
[0008] In this way, high starting torque can be achieved advantageously with no or at least significantly reduced response delay. Furthermore, when using discrete signal injection, rotor position can be determined with no or only a few sensors. For example, the use of Hall sensors is particularly reduced. Therefore, the cost and maintenance expenses of the corresponding motor are lowered.
[0009] Furthermore, by determining the rotor speed reached due to acceleration in step c), it is particularly simple and reliable to determine whether the expected rotor speed corresponding to the current rotating field frequency has been set. For this purpose, a threshold is defined using a first predetermined speed value. When the speed is higher than the threshold, in addition to determining the second position of the rotor, a closed-loop operation mode will be switched (particularly from acceleration of the rotor through a controlled rotating field).
[0010] By detecting the rotor's achieved speed, it can be identified whether the rotor accelerates too rapidly under a given load (e.g., through a change in the controlled rotational field frequency in step b). This test allows for an initial, advantageous attempt to start the rotor with lower current and / or power. Because operation can be performed with lower current (especially current amplitude) and / or power (especially power amplitude) (e.g., when the motor coils are energized), the electronic systems controlling the starting method and the motor itself can be preserved, and overheating can be avoided.
[0011] Therefore, the proposed method enables the economical and efficient starting of EC motors with high starting torque, while providing the highest possible comfort for operators and reducing the load on the motor and electronic systems.
[0012] Based on the first position of the rotor determined in step a), one or more coils in the motor can be advantageously determined, for which the acceleration of the rotor (especially the acceleration in step b) must be at least temporarily energized (especially at the beginning stage of the acceleration in step b).
[0013] The discrete signal injection can apply a periodic high-frequency voltage signal to the motor coil and then determine the first position based on the generated high-frequency current.
[0014] The acceleration process described in step b) advantageously employs an open-loop operation mode. The acceleration process causes the rotor speed to rapidly increase, i.e., rise. For example, the speed change curve during the acceleration process can be calculated and / or determined before the acceleration process in step b) begins. For example, the speed change curve and its rising slope may depend on whether step b) is being performed for the first time or is being repeated a certain number of times. A detailed explanation of the repetition option will be provided below.
[0015] In the embodiments, the acceleration process described in step b) can be time-dependent or time-dependent. Particularly advantageously, the acceleration process described in step b) has different rates of rotational speed change in different time periods. For example, a squared rotational speed change can be performed in at least the first time period. Alternatively or supplemented, a linear rotational speed change can also be performed in at least the second time period.
[0016] In one embodiment, the rotor acceleration process described in step b) refers to adjusting the motor current based on the motor temperature, particularly the initial motor current during acceleration.
[0017] In one embodiment, the rotor acceleration process in step b) includes a control device that keeps the motor current amplitude constant. This allows for a rapid ramp-up of the rotational speed. Alternatively, the method can be adjusted to achieve a relatively smooth rotor start-up process, with a longer start-up time compared to a rapid ramp-up. To achieve a smooth rotor start-up, the rotor acceleration process in step b) can employ a variable motor current amplitude.
[0018] During the rotor acceleration process in step b), it is advantageous to employ a current frequency (If) starting method at least for a portion of the time and / or at least for a portion of the region. For example, open-loop operation can be performed entirely or partially using a current frequency starting method.
[0019] The advantage of accelerating the rotor by a controlled rotating field in step b) is that the frequency of the rotating field is increased at least in stages.
[0020] Alternatively, the acceleration process of the rotor described in step b) can be performed within a controlled rotating field over a specified time period. In particular, when step b) is repeated as detailed below, the specified time period will be adjusted, in particular, extended, compared to the previous execution of step b).
[0021] The frequency of the rotating field (of the controlled rotating field) is the same as the frequency of the controlled rotating field. The amplitude of the motor current depends in particular on the frequency of the rotating field.
[0022] The advantage of determining the rotor speed in step c) lies in the use of field-oriented control (FOC) with a flux observer. For example, determining the rotor speed in step c) may include determining one or more voltages induced in the motor's coils, especially after the coil current has been adjusted to zero.
[0023] For example, determining the rotor speed in step c) can be done using either a direct or indirect method of rotor speed measurement. For instance, the speed can be indirectly determined using the motor voltage. For example, the characteristic that there is usually a linear relationship between the voltage induced in the motor windings (motor voltage) and the rotational speed (back electromotive force voltage) can be utilized. Furthermore, those skilled in the art will know that since there is a known correlation between rotational speed and angular velocity, angular velocity can also be measured instead of rotational speed.
[0024] In one embodiment, the determination of the rotor speed based on the back electromotive force in step c) is initiated after the acceleration process in step b). However, in some embodiments, the determination of the rotor speed based on the back electromotive force in step c) may also be initiated at least partially synchronously with the rotor acceleration process in step b). In other words, steps b) and c) at least partially overlap, thus representing at least partially parallel steps.
[0025] The term "back EMF" refers to the reverse electromotive force, a concept that is common knowledge to those skilled in the art.
[0026] In particular, during the switch to closed-loop operation in step e), information on the first rotor position and / or the second rotor position is included. Therefore, the switch can be implemented based on the corresponding rotor position.
[0027] Specifically, in step e), after switching to closed-loop operation, the third position of the rotor is continuously determined based on the back electromotive force. For example, the continuous determination of the rotor's third position may include or manifest as the periodic repetition of the determination of the rotor's third position. Therefore, the determination of the rotor's third position can be completed within a specified time interval.
[0028] Therefore, the current position value of the rotor can be effectively used in subsequent measures. A new value for the third position can be obtained with each new measurement.
[0029] The first position can be the angular position of the rotor. The second position can be the angular position of the rotor. The third position can be the angular position of the rotor.
[0030] When the rotational speed measured in step c) is greater than the first predetermined rotational speed value, advantageously only the second position is needed. However, it is particularly advantageous that the second position can be determined in step c) based on data that is the same as (especially simultaneously with) the rotor rotational speed. Therefore, the engine starts up faster, resulting in particularly high efficiency. Thus, in an alternative embodiment, it can be specified that the determination of the rotor's second position is not performed in step e), but is determined in step c), particularly based on the back electromotive force, simultaneously with and / or based on data that is the same as the rotor rotational speed. Then, step c) is as follows: after reaching the rotational field frequency specified in step b), the rotor rotational speed and the rotor's second position are determined based on, particularly a single, back electromotive force. At this point, step e) can be optionally: if the rotational speed determined in step c) is greater than the first predetermined rotational speed value: switch to closed-loop operation mode based on the back electromotive force. For this alternative embodiment, all the advantages and alternatives described are equally applicable unless otherwise indicated. This embodiment will be described again below in a separate aspect.
[0031] Controlled rotating field specifically refers to an open-loop control (also referred to here as open-loop operation mode), achieved particularly by applying current, defining angles, and / or adjusting the amplitude of the motor current. The applied current specifically refers to the current flowing into the motor (motor phase). Depending on the internal wiring, the current may be distributed to different winding ends.
[0032] The amplitude of motor current specifically refers to the motor current component i that forms the magnetic field. d The motor current component i that generates torque q The combined amplitude of the motor current. For example, the motor current amplitude can be determined based on the phase current. and Calculations yielded this result. The amplitude of the motor current. Current and It can be calculated using the following formula: Since there are no (actual) d and q currents in open-loop operation, it is more advantageous to use the phase current relationship for analysis.
[0033] Especially in closed-loop operation mode, which specifically features or manifests as closed-loop current regulation, the rotor angle of the motor is known. For example, this mode can be used for coordinate transformation of the motor current. In open-loop operation mode, especially when employing or manifesting as open-loop current control, the rotor angle of the motor is typically assumed (e.g., an "up" angle derived from the open-loop rise). However, this angle is not necessarily consistent with the current rotor angle of the motor.
[0034] Closed-loop operation can also be called closed-loop current control. In particular, closed-loop operation encompasses field-oriented control (FOC).
[0035] For example, closed-loop operation may include: initializing the flux observer based on the rotor position, particularly the second position of the rotor; and driving the rotor operation through field-oriented control (FOC).
[0036] As an alternative or supplement, the discrete signal injection in step a) may also include a specified and / or limited number of pulses.
[0037] The advantage lies in pre-defining the shape, duration (especially half-width), and / or phase sequence of each pulse. In various embodiments, each pulse has the same configuration. The advantage is that the time interval between consecutive pulses is predetermined.
[0038] For example, the discrete signal injection in step a) has 1 to 100 pulses.
[0039] For example, the discrete signal injection in step a) has at least one, in particular exactly one, INFORM pulse. INFORM stands for indirect flux detection of online reactance measurement, which is well known to those skilled in the art.
[0040] As an alternative or supplementary option, step b) may also include: rotor acceleration, wherein the motor current is adjustable and the amplitude of the motor current varies with the controlled rotating field, wherein the amplitude of the motor current is kept in particular constant.
[0041] The method described above enables motor acceleration in a particularly reliable and relatively simple manner.
[0042] As an alternative or supplementary option, step c) may also include: determining the rotor speed after a specified time based on the back electromotive force.
[0043] Specifically, the specified time refers to the time elapsed since the acceleration start in step b).
[0044] Therefore, step c) of determining the rotor speed based on the back electromotive force will be performed after the predetermined rotational frequency described in step b) is reached and a specified time is reached, i.e., after both conditions are met. Specifically, the predetermined rotational frequency is reached after the specified time. Therefore, the specified time corresponds to the duration required to reach the predetermined rotational frequency.
[0045] In step b), determining the rotational speed based on the specified time allows for further refinement of the starting conditions for speed measurement. By refining the time, the rotational speed can be determined particularly easily and reliably from the moment the initial acceleration process is completed as planned or should have been completed. This method enables the acceleration process to be executed with high reliability.
[0046] As an alternative or supplementary option, step c) may also include: determining the rotor speed based on the set motor voltage, especially reducing the motor current amplitude in time before determining the speed.
[0047] For example, by using zero-current control with a set motor voltage, the motor voltage (the voltage induced in the windings) can be determined more robustly and accurately.
[0048] Alternatively, the method states that zero-current control is performed sequentially between step b) and step c).
[0049] For example, zero-current control can be manifested by adjusting the motor current in the three motor phases to 0A.
[0050] Step c) particularly includes adjusting the motor current amplitude to a set value of zero, and / or reducing the motor current to zero or near zero, particularly by adjusting the motor current amplitude to a set value of zero.
[0051] As an alternative or supplementary option, step c) may also include: determining the rotor speed by measuring the motor voltage under no-load conditions.
[0052] This provides a particularly simple yet reliable method for measuring rotational speed.
[0053] This can be achieved by running the rotor under no-load conditions and measuring the motor voltage during this period. For example, the motor voltage could be the induced voltage during no-load conditions.
[0054] When no voltage is applied to the motor phase, the rotor is in an unloaded state.
[0055] Alternatively or as a supplement, it may be stipulated that if the rotational speed measured in step c) is less than the first predetermined rotational speed value, then step f) which needs to be performed after step d) includes: braking the rotor and repeating steps a) to d).
[0056] Therefore, if the rotational speed measured in step c) is lower than the first predetermined rotational speed value, i.e., the rotor fails to reach the expected rotational speed corresponding to the rotational field frequency present in step c) in the corresponding embodiment, the starting process can be attempted again by restarting after braking the rotor, especially using adjusted motor parameters. For example, a higher current (especially current amplitude) and / or power (especially power amplitude) can be used at this time (e.g., when energizing the motor coils). In this case, it is appropriate not to perform step e).
[0057] In some embodiments, it is specified that steps a) to d) are repeated promptly after rotor braking, and step e) is performed if necessary.
[0058] Repeating step b), especially repeating steps a) to d), can reduce motor shock compared to the previous step b). This is because when repeating step b), especially when repeating steps a) to d), it is possible to easily adjust the acceleration and / or shock of the speed increase.
[0059] In particular, it can be specified that when repeating step b), the controlled rotating field and / or the motor current amplitude and / or motor temperature related to the frequency of the rotating field are adjusted compared to the previous step b).
[0060] As an alternative or supplementary option, step f) may also include: braking by short-circuit braking.
[0061] Therefore, the rotor braking in step f) may include performing short-circuit braking, in particular for a specified duration.
[0062] For example, braking can be performed for a predetermined duration. In an embodiment, rotor braking includes braking the rotor to a stop. For example, a longer predetermined duration can be selected. This allows for reliable stopping.
[0063] As an alternative or supplementary option, step f) may also include: braking until the rotor speed is lower than a second predetermined speed value.
[0064] Therefore, it is possible to establish clearly defined conditions with particular reliability so that the steps can be repeated.
[0065] The second predetermined speed value is at most 20% of the rotor rated speed and / or the first predetermined speed value, and at least 10% of the rotor rated speed and / or the first predetermined speed value.
[0066] As an alternative or supplementary option, step f) may also include: determining the rotational speed based on the amplitude and / or frequency of the motor current.
[0067] For example, the specified duration can be determined based on the engine speed. Therefore, the braking duration set for higher engine speeds can be longer than the braking time set for lower engine speeds. As a result, braking can be performed very efficiently as part of the starting process.
[0068] As an alternative or supplement, it may also be specified that, when performing step b), the amplitude of the controlled rotating field and / or the motor current is adjusted, in particular, according to the frequency of the rotating field, compared to the previous step b).
[0069] For example, by adjusting the amplitude of the controlled rotating field and / or the motor current, it is particularly simple and reliable to respond to situations where a higher load than expected is encountered, and under these conditions, to allow the rotor to start up fully on the next startup (or after one or more repetitions). This solution is particularly useful, for example, in the case of motor-driven jamming devices (such as the resin-coated blades of hedge trimmers).
[0070] By adjusting the parameters, when repeating step b), the rotor can achieve a better start-up effect with less impact and / or lower acceleration compared to the previous step b).
[0071] For example, when repeating step b), a controlled rotating field can be generated at a reduced rate of change of the rotating field frequency compared to the previous step b). This allows for a degree of safer "carrying" of higher loads.
[0072] For example, when repeating step b), the amplitude of the motor current can be increased and / or decreased compared to the previous step b). This allows for a degree of safer "carrying" of higher loads. Therefore, it is possible to start with a lower current and then set a higher current as needed.
[0073] Low current has many advantages as described above, which can effectively reduce the thermal load on electronic systems and / or motors.
[0074] Optionally, when repeating step b), the rotor speed can be determined based on the back electromotive force after a new specified time has been reached, compared to the previous step b). Therefore, there is a difference in the time required to determine the speed during the first measurement and the repeat.
[0075] In the multiple repetitions of step b), in at least one of the at least one further repetitions, the controlled rotating field and / or motor current amplitude are advantageously adjusted, wherein the absolute changes of the parameters are different in each case, especially the rate of change of the rotating field frequency and / or the rate of change of the motor current amplitude.
[0076] As an alternative or supplement, it may also be stipulated that, when repeating step b), the controlled rotating field and / or motor current amplitude, which depend particularly on the frequency of the rotating field, are adjusted in progressively larger increments compared to the previous step b).
[0077] In other words, with each repetition of step b), the amplitude of the controlled rotating field and / or the motor current is adjusted. Therefore, the motor can be started particularly efficiently.
[0078] According to a second aspect, the present invention provides a method for starting an EC motor, the motor having a stator and a rotor, the method comprising the following steps: a) Determine the first position of the rotor when it is stationary by injecting discrete signals; b) Achieving rotor acceleration through a controlled rotating field; c) After the predetermined rotational field frequency is reached in step b), the rotor speed and the second position of the rotor are determined based on the back electromotive force, especially a single back electromotive force. d) Compare the rotational speed measured in step c) with the first predetermined rotational speed value; and e) If the rotational speed measured in step c) is greater than the first predetermined rotational speed value: switch to closed-loop operation mode based on back electromotive force.
[0079] Therefore, the main feature that distinguishes the method described in the second aspect of the present invention from the method described in the first aspect is that the determination of the second position of the rotor is not performed in step e), but is completed in step c). Therefore, the motor starts up faster, thereby achieving particularly high efficiency.
[0080] With respect to the method described in the second aspect of the invention, all advantages and options described for the method described in the first aspect apply, unless otherwise indicated. Therefore, reference may be made to the foregoing embodiments in this regard.
[0081] According to a third aspect, the present invention provides a component comprising an EC motor having a stator and a rotor, and a control device electrically connected to or connectable to the EC motor, wherein the control device is configured to perform a method according to the first and / or second aspects of the present invention.
[0082] All the advantages of the methods described in the first and / or second aspects of the present invention also apply to the components described in the third aspect. Therefore, reference may be made to the foregoing embodiments in this regard.
[0083] The features described in the methods of the first and / or second aspects of the present invention may also be provided in the components, either alone or in any combination, especially in the control device, unless otherwise indicated.
[0084] In particular, the control device is configured to perform the methods according to the first and / or second aspects of the invention. Furthermore, the control device can interact with other components of the motor, such as the rotor and stator. The control device can establish an effective connection with the rotor and / or stator.
[0085] For example, the control device can be implemented through software, hardware, or a combination of both. The control device can be a data processing device. The control device can replace or supplement any combination of a memory, processor, receiving device, transmitting device, or such devices. The control device can replace or supplement providing and / or possessing the availability and / or having all the aforementioned devices, particularly all necessary resources, such as resources existing in the form of software and / or hardware resources.
[0086] The control device is suitable for establishing an electrical connection and / or data technology connection with the motor.
[0087] The control device is preferably equipped with an interface for receiving sensor signals and / or sending commands, as well as tools for processing, evaluating and / or analyzing the corresponding signals.
[0088] According to a fourth aspect, the present invention provides a gardening device, an apparatus for garden maintenance or road maintenance stations, and / or an agricultural or forestry apparatus, each of which comprises components according to a third aspect of the invention, wherein (i) the gardening device or apparatus is operable by a battery, and / or (ii) the gardening device or apparatus is designed as a hedge trimmer, rotary shears, grass shears, hedge cutter, pruning shears, high branch saw, blower, cleaning device (especially a pressure washer), vacuuming device, spraying and / or misting device, saw, wood cutter, pruning shears, multi-tool, shrub cutter, rock cutter, or cutting grinder.
[0089] All the advantages of the methods described in the first and / or second aspects of the present invention also apply to the devices and apparatus described in the fourth aspect of the present invention. Therefore, reference may be made to the foregoing embodiments in this regard. Attached Figure Description
[0090] Other features and advantages of the present invention will be illustrated by the specific embodiments shown in the following description and accompanying drawings. Illustrations: Figure 1 This is a flowchart of a method according to the first aspect of the present invention; Figure 2 This is a flowchart of a method according to a second aspect of the present invention; Figure 3 A schematic diagram of components according to a third aspect of the present invention; and Figure 4 This is a schematic diagram of a gardening device and / or apparatus according to the fourth aspect of the present invention. Detailed Implementation
[0091] Figure 1 A flowchart of a method 100 according to a first aspect of the present invention is shown. This method is used to start an EC motor having a stator and a rotor.
[0092] In step 101, the first position of the rotor when it is stationary is determined by injecting discrete signals. The first position can be an angle of the rotor.
[0093] For example, discrete signal injection can be achieved using INFORM pulses.
[0094] In step 103, the rotor is accelerated by a controlled rotating field.
[0095] The acceleration process can employ an open-loop operation mode. In this mode, the rotor speed will increase dramatically, i.e., rise rapidly. For example, the speed change curve can be calculated before acceleration begins. For example, the speed change curve and the rising process may depend on how many times step 103 is repeated. For example, the acceleration process is time-dependent. In this case, different rates of change can be specified for different time periods. For example, a linear rate of change can be provided over a time range.
[0096] In step 105, after the predetermined rotational field frequency in step 103 is reached, the rotor speed is determined based on the back electromotive force.
[0097] In step 107, the rotational speed determined in step 105 is compared with the first predetermined rotational speed value.
[0098] If the rotational speed measured in step 105 is greater than the first predetermined rotational speed value, then the second position of the rotor is determined in step 109 based on the back electromotive force, and the operation mode is switched to closed loop based on the back electromotive force.
[0099] The second position can be an angle of the rotor.
[0100] For example, during closed-loop operation, the flux observer can be initialized based on the second position of the rotor, and the rotor can be operated through field-oriented control (FOC).
[0101] Optionally, if the rotational speed measured in step 105 is less than a first predetermined rotational speed value, the rotor may be braked in step 111 after step 107, and steps 101 to 107 may be repeated. Subsequently, based on the rotational speed determined in step 105, the rotor may be operated according to step 109, or the rotor may be braked again in step 111, and optionally the cycle of steps 101 to 107 may be repeated at least once.
[0102] Figure 2 A flowchart of a method 200 according to a second aspect of the present invention is shown. This method is also used to start an EC motor having a stator and a rotor. The method is combined with that according to a first aspect of the present invention. Figure 1 The process described in flowchart 100 is very similar. Steps 201, 203, 207 and 211 correspond to steps 101, 103, 107 and 111, respectively.
[0103] However, in step 205, after the predetermined rotational field frequency is reached in step 203, the rotor speed and the second position of the rotor will be determined based on the back electromotive force, especially the single back electromotive force.
[0104] The second position can be an angle of the rotor.
[0105] If the rotational speed measured in step 205 is greater than the first predetermined rotational speed value, then the operation mode is switched to closed-loop mode in step 209 based on the back electromotive force.
[0106] In other words, the determination of the second position of the rotor is now completed in step 205, rather than in step 209.
[0107] Figure 3 A schematic diagram of component 301 according to a third aspect of the present invention is shown.
[0108] The component 301 has an EC motor 303. The EC motor has a stator 305 and a rotor 307. The EC motor 301 is electrically connected to a control device 309.
[0109] The control device 309 is configured to perform the method according to the first and / or second aspects of the present invention. Therefore, the control device 309 is capable of starting the motor 303 in an optimal manner. For example, the starting can be performed according to the first aspect of the present invention, referring to... Figure 1 The method described in flowchart 100, or the method employed according to the second aspect of the present invention, with reference to Figure 2 The method described in flowchart 200 is used to achieve this.
[0110] Figure 4 A schematic diagram of a gardening device and / or apparatus 311 according to a fourth aspect of the present invention is shown.
[0111] The device or apparatus 311 has a component 313 according to the third aspect of the invention. For example, component 313 may be the same as component 301.
[0112] For example, the device can be used in landscape maintenance or road maintenance stations, and / or as an agricultural and forestry device. For example, device 311 may be hedge trimmers or chainsaws.
[0113] The features disclosed in the foregoing specification, drawings and claims, whether present individually or in any combination, can serve as core elements of the various embodiments of the present invention.
[0114] Figure Labels 100 Flowchart 101 Determine the first position of the motor rotor 103 Rotor Acceleration 105. Determine the rotor speed. 107. Compare the measured rotational speed with the predetermined rotational speed value. 109 Determine the second position of the rotor and switch to closed-loop operation mode. 111 Rotor Brake 200 Flowchart 201 Determine the first position of the motor rotor 203 Rotor Acceleration 205 Determine the rotor speed and second position 207. Compare the measured rotational speed with the predetermined rotational speed value. 209 Switch to closed-loop operation mode 211 Rotor Braking Component 301 303 EC motor 305 stator 307 Rotor 309 Control device 311 Equipment and apparatus 313 components
Claims
1. A method for starting an EC motor (303), the motor having a stator (305) and a rotor (307), the method comprising the steps of: a) Determine the first position (101) of the rotor (307) when it is stationary by injecting discrete signals; b) Accelerating the rotor (307) (103) through a controlled rotating field; c) Determine the rotational speed (105) of the rotor (307) based on the back electromotive force after reaching the predetermined rotational field frequency in step b); d) Compare the rotational speed determined in step c) with the first predetermined rotational speed value (107); and e) If the rotational speed determined in step c) is greater than the first predetermined rotational speed value: determine the second position of the rotor (307) based on the back electromotive force, and switch to closed-loop operation mode (109) based on the back electromotive force.
2. The method according to claim 1, wherein the discrete signal injection in step a) comprises a predetermined number and / or a limited number of pulses.
3. The method according to any one of the preceding claims, wherein step b) comprises: The rotor (307) is accelerated, wherein the motor current is adjustable and the amplitude of the motor current varies with the controlled rotating field, wherein the amplitude of the motor current is particularly constant.
4. The method according to any one of the preceding claims, wherein step c) comprises: The rotational speed of the rotor (307) after a specified time is determined based on the back electromotive force.
5. The method according to any one of the preceding claims, wherein step c) comprises: The rotational speed of the rotor (307) is determined based on the set motor voltage, and in particular, the amplitude of the motor current is reduced in a timely manner before the rotational speed is determined.
6. The method according to any one of the preceding claims, wherein step c) comprises: The rotational speed of the rotor (307) is determined by measuring the motor voltage under no-load conditions.
7. The method according to any one of the preceding claims, wherein, If the rotational speed determined in step c) is lower than the first predetermined rotational speed value, then step f) performed after step d) includes: braking (111) the rotor (307) and repeating steps a) to d).
8. The method of claim 7, wherein step f) comprises: Braking is achieved through short-circuit braking (111).
9. The method according to any one of claims 7 to 8, wherein step f) comprises: Braking (111) until the rotational speed of the rotor (307) is lower than the second predetermined rotational speed value.
10. The method according to any one of claims 7 to 9, wherein step f) comprises: The rotational speed is determined based on the amplitude of the motor current and / or the frequency of the motor current.
11. The method according to any one of claims 7 to 10, wherein, when repeating step b), the amplitude of the controlled rotating field and / or, in particular, the motor current, which depends on the frequency of the rotating field, is adjusted relative to the previous step b).
12. The method according to any one of claims 7 to 11, wherein, when repeating step b), the amplitude of the controlled rotating field and / or, in particular, the motor current, which depends on the frequency of the rotating field, is gradually adjusted in increasing increments compared to the previous step b).
13. A component (301) comprising an EC motor (303) having a stator (305) and a rotor (307), and a control device (309) electrically connected to or electrically connectable to the EC motor (303), wherein the control device (309) is configured to perform the method according to any one of the preceding claims.
14. A gardening device (311), an apparatus (311) for garden maintenance or road maintenance stations, and / or an agricultural or forestry apparatus (311), each comprising the component (301) according to claim 13, wherein (i) the gardening device (311) or apparatus (311) is operable by a battery, and / or (ii) the gardening device (311) or apparatus (311) is designed as a hedge trimmer, rotary shears, grass shears, hedge cutter, pruning shears, high branch saw, blower, cleaning device (especially a pressure washer), vacuuming device, spraying and / or misting device, saw, wood cutter, pruning shears, multi-tool, shrub cutter, rock cutter, or cutting grinder.