Braking of a rotating brushless DC motor of an electrically driven machining device

Abstract

The invention relates to a method for braking a rotating brushless DC motor (2) of an electrically driven machining device (1), in particular for achieving a standstill of the DC motor (2), wherein the DC motor (2) can be controlled by means of a bridge circuit (3) of the machining device (1) to perform electronic commutation, - wherein the method comprises: - providing a rotational speed variable (nG) representative of a rotational speed (n) of the DC motor (2), in particular repeatedly, and - braking the rotating DC motor (2) by varying a duty cycle (D) of a pulse-duration modulation (PDM) when controlling the bridge circuit (3), wherein the duty cycle (D) has values between 0 and less than 1, depending on the provided rotational speed variable (nG), if the rotational speed (n) is greater than 0.

Description

[0001] Method for braking a rotating brushless DC motor of an electrically driven machining device and electrically driven machining device, and in particular battery, for carrying out the method

[0002] SCOPE OF APPLICATION AND STATE OF THE ART

[0003] The invention relates to a method for braking a rotating brushless DC motor of an electrically driven machining device and the electrically driven machining device, and in particular a battery, for carrying out the method.

[0004] TASK AND SOLUTION

[0005] The invention is based on the objective of providing a method for braking a rotating brushless DC motor of an electrically driven processing device and the electrically driven processing device, and in particular a battery, for carrying out the method, which, in particular, each have improved properties.

[0006] The invention solves this problem by providing a method and an electrically driven processing device, and in particular a battery, as described in the independent claims. Advantageous further developments and / or embodiments of the invention are described in the dependent claims.

[0007] The method according to the invention is for braking a rotating brushless DC motor of an electrically driven machine tool, in particular for bringing the DC motor to a standstill. The DC motor can be electronically commutated by means of a bridge circuit of the machine tool. The method comprises, in particular, the step of: braking the rotating DC motor by varying the duty cycle of a pulse duration modulation during or with the activation of the bridge circuit, wherein the duty cycle has, in particular, at least and / or different values ​​between 0 (0% or percent), in particular greater than 0, and less than 1 (100%), if the rotational speed of the DC motor is greater than 0.

[0008] Additionally, the method, in particular the step of providing a rotational speed value representative of the rotational speed, especially repeated several times. Braking is performed by varying the duty cycle depending on the provided rotational speed value, especially for values ​​greater than 0.

[0009] Furthermore, additionally or alternatively, the control is carried out in such a way that for a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a braking period, in particular until standstill, the value of a field-generating current is at most 2 times as large, in particular a maximum of 1.5 times as large, in particular a maximum equal to or smaller than the value of a torque-generating current.

[0010] Furthermore, or alternatively, the method, in particular the provision, includes the following step: acquiring a current value representative of the current of the DC motor, in particular repeatedly. Braking is performed by varying the duty cycle depending on the acquired current value. In particular, the speed value is provided depending on the acquired current value.

[0011] This allows for fast and / or simple braking, particularly avoiding excessive heat generation. Additionally or alternatively, this simplifies the process and, in particular, the processing equipment.

[0012] In particular, the process, braking, commutation, variation, control, provision and / or acquisition can be implemented automatically and / or by computer and / or carried out by means of the processing device.

[0013] The term "to take place" or the phrase "to be carried out" or "to be implemented" can be used synonymously with the phrase "to be executed".

[0014] The process can be continuous.

[0015] Braking can be electric.

[0016] The terms "deceleration" or "braking process" or the phrase "reducing the speed" can be used synonymously with the term "braking".

[0017] The term "reduce" or "lower" can be used synonymously with the term "lower".

[0018] The rotational speed can refer to the motor speed. The braking can refer to the braking of a rotor in a DC motor.

[0019] The term “EC motor” (abbreviation of English electronically commutated motor) can be used synonymously with the term “brushless DC motor” (abbreviation BLDC or BL motor).

[0020] The DC motor can be three-phase and / or a permanent magnet DC motor and / or a DC drive motor.

[0021] The DC motor can be used to drive a machining tool of the machining device.

[0022] The processing equipment can be ground-based and / or handheld, in particular hand-carried, and / or be a garden, forestry, construction, and / or soil cultivation tool. In particular, the hand-carried processing equipment can have a mass of a maximum of 50 kg (kilograms), in particular a maximum of 20 kg, in particular a maximum of 10 kg, in particular a maximum of 5 kg, and / or a minimum of 0.2 kg, in particular a minimum of 0.5 kg, in particular a minimum of 1 kg, in particular a minimum of 2 kg. Additionally or alternatively, the garden, forestry, construction, and / or soil cultivation tool can be a saw, in particular a chainsaw, or an angle grinder, or a brush cutter, or a lawnmower, or a drilling rig.

[0023] The phrase "until the standstill" can be used synonymously with the phrase "to achieve the standstill".

[0024] The term "switching bridge" can be used synonymously with the term "bridge circuit".

[0025] The bridge circuit can be three-phase and / or a B6 bridge circuit, in particular with B6 diodes, and / or have three push-pull stages and / or, in particular, exactly three high-side switches and, in particular, exactly three low-side switches. In particular, the high-side switches and the low-side switches can be transistors, in particular semiconductor switches, and / or MOSFETs and / or IGBTs. Additionally or alternatively, the bridge circuit, in particular the high-side switches and the low-side switches, can have diodes, in particular protection diodes, in particular freewheeling diodes, connected in parallel in reverse bias to the high-side switches and the low-side switches.

[0026] Commutation can be block commutation and / or brushless and / or sensorless. The terms "control," "monitoring," or "switching" can be used synonymously with "controlling."

[0027] The terms "include" or "have" can be used synonymously with the term "exhibits".

[0028] The terms “change”, “place” or “specify” or the phrase “determine and adapt” can be used synonymously with the term “vary”.

[0029] The variation can be repeated several times.

[0030] The duty cycle can be variable.

[0031] The term "pulse width modulation" can be used synonymously with the term "pulse duration modulation".

[0032] The duty cycle can have at least three, and in particular at least ten, values ​​greater than 0 and less than 1.

[0033] The term "amount" can be used synonymously with the term "value".

[0034] The term "higher" can be used synonymously with the term "larger".

[0035] The term "lower" can be used synonymously with the term "smaller".

[0036] The term "like" can be used synonymously with the term "as".

[0037] The terms "if" or "while" can be used synonymously with the term "if".

[0038] The provision may involve determination, in particular recording, and in particular be.

[0039] At least three, in particular at least ten, in particular different, values ​​of the rotational speed can be provided.

[0040] The rotational speed can be physical.

[0041] The term "characteristic" can be used synonymously with the term "representative". The rotational speed can be the rotational speed.

[0042] Repeatedly can be regular, continuous and / or ongoing.

[0043] The wording “based on 1 can be used synonymously with the phrase "depending on".

[0044] Braking can be performed in conjunction with the provisioning process.

[0045] The phrase “at the same time as” or the term “during” can be used synonymously with the phrase “at the same time as”.

[0046] The control can take the form of vector positioning or control.

[0047] The term "field-oriented" can be used synonymously for the term component "vector-".

[0048] The term "high" can be used synonymously with the term "large".

[0049] The term "measuring" can be used synonymously with the term "recording".

[0050] At least three, in particular at least ten, in particular different, values ​​of the current quantity can be recorded.

[0051] The current quantity can be physical.

[0052] The current quantity can be the current.

[0053] The current can be a motor current, in particular a stator current of a stator of a DC motor.

[0054] Braking can be performed in sync with the detection.

[0055] The process, particularly braking, can be executed by triggering a braking event. Regular commutation can be switched off or terminated before and / or after the braking event. This allows phases, especially those of a DC motor, to be floating.

[0056] Furthermore, reference is made to the specialist literature.

[0057] Alternatively, when braking by reducing the speed and / or over a range of speed or speed magnitude, the duty cycle can have a fixed value and / or not be varied.

[0058] Alternatively or additionally, braking can be performed by varying the duty cycle over time, particularly using a lookup table. Specifically, the duty cycle can be increased when braking by reducing the rotational speed.

[0059] Alternatively or additionally, the provision can include: Detecting a back-EMF (back electromotive force) quantity representative of a back-EMF caused, in particular induced, by the rotating DC motor, especially repeatedly. The speed quantity can be provided as a function of the detected force quantity. In particular, the force quantity can be the force and / or a voltage, especially a generator voltage.

[0060] Alternatively or additionally, the provision can include: acquiring a rotor position value representative of the position of one, in particular the, rotor of the DC motor, especially repeatedly and / or by means of a sensor, in particular a Hall sensor. The provision of the rotational speed value can be implemented depending on the acquired rotor position value.

[0061] In one embodiment of the invention, the provision comprises: acquiring, in particular at least two, in particular exactly three, and / or all, phase current quantities representative of, in particular at least two, in particular exactly three, and / or all, phase currents of the DC motor, in particular time profiles of the phase current quantities. Providing the speed quantity as a function of, or by providing, a time duration quantity representative of a time interval between points in time at which the values ​​of the acquired phase current quantities are equal, in particular large. This enables a particularly efficient, in particular calibration-free and / or computationally intensive, provision of the speed quantity. In particular, the phase current quantities can be the phase currents. Additionally or alternatively, the provision can be automatic and / or computer-implemented and / or performed by means of the processing device.Furthermore, or alternatively, at least three, and in particular at least ten, and in particular different, values ​​of the duration parameter can be provided. Furthermore, or alternatively, the duration parameter can be the duration itself. Furthermore, or alternatively, the duration can be the shortest possible duration. Furthermore, or alternatively, the time points can be the next possible time points. Furthermore, or alternatively, the curves can intersect at the specified time points, and / or the time points can be intersection points of the curves. Furthermore, or alternatively, this can be referred to as sector analysis. For further details, please refer to the relevant literature.

[0062] Alternatively or additionally, the speed value can be provided as a function of an angular value representative of an angle across, in particular, two, detected phase current values. Specifically, the angular value can be the angle. Additionally or alternatively, this can be referred to as step time detection.

[0063] Alternatively or additionally, the provision of the rotational speed can be implemented as a function of the provision of an angular velocity quantity representative of an angular velocity over a time interval between zero crossings of the measured phase current quantities. In particular, the angular velocity quantity can be the angular velocity.

[0064] In a further development or embodiment of the invention, the method, in particular the following step, comprises: controlling the bridge circuit with a fixed value for the duty cycle of the pulse duration modulation to provide the rotational speed and / or the current, and, prior to braking, varying the duty cycle depending on the provided rotational speed and / or the current. This enables particularly accurate provision of the rotational speed and / or accurate current measurement. In particular, the fixed value can be between 0, especially 0.6, and 1, especially 0.75. Additionally or alternatively, the fixed value can be preset. In particular, preset can be factory preset. Additionally or alternatively, the terms "determined," "stored," or "pre-programmed" can be used synonymously with "preset."Additionally or alternatively, the varied duty cycle can have a value that is less than, equal to, or greater than the fixed value.

[0065] In a further development of the invention, the method, in particular the step of, involves: controlling a brake switch of the processing device, which differs from the bridge circuit, into a closed switching state, in particular at or in conjunction with the provision of the rotational speed and / or the detection of the current, and at or in conjunction with braking such that a load applies stress to and decelerates the DC motor. This enables particularly rapid braking. In particular, the control can be automatic and / or computer-implemented and / or carried out by means of the processing device. Additionally or alternatively, the brake switch can be electrical, in particular a transistor, in particular a MOSFET. Furthermore, the term "continuous" can be used synonymously with "continuously" or "permanently".Furthermore, or alternatively, the term "consumer" can be used synonymously with the term "load". Furthermore, or alternatively, the load can be electrical and / or different from the bridge circuit and / or the DC motor. Furthermore, or alternatively, the method, in particular the step of, can include: actuating the brake switch to an open switching state after braking, in particular until standstill, and / or, if the rotational speed is zero, in such a way, in particular continuously, that the load does not stress and decelerate the DC motor. Furthermore, or alternatively, the closed switching state can be an on switching state and / or a conductive switching state. Furthermore, or alternatively, the open switching state can be an off switching state and / or a non-conductive or isolating switching state.

[0066] In one embodiment of the invention, the load includes a braking resistor of the processing device. In particular, a brake series circuit of the brake switch and the brake resistor is connected in parallel to the bridge circuit, specifically either on an input side or an output side. Additionally or alternatively, the load includes a battery. In particular, a brake series circuit of the brake switch and the battery is connected in parallel to the bridge circuit on the input side. This enables absorption and / or recuperation, especially of energy from the DC motor, into the brake resistor and / or the battery, for which information about the battery may be required. In particular, the brake resistor can be electrical, especially resistive, and / or have a value, especially a fixed value, especially greater than 0.Additionally or alternatively, the brake series circuit can be connected in series on the input side in an intermediate circuit and / or in parallel with buffer capacitors of the processing device. Furthermore, additionally or alternatively, the brake series circuit can be connected in series on the output side with phases of the DC motor. Furthermore, additionally or alternatively, the connection can be direct and / or fixed or permanent. Furthermore, additionally or alternatively, the term "electrically arranged" can be used synonymously with "connected in series." Furthermore, additionally or alternatively, the braking resistor can be mechanically or geometrically arranged in a cooling airflow, particularly in the vicinity of electronics, especially the bridge circuit and / or control electronics, on a module of the electronics, and / or on a metal housing.Additionally or alternatively, in the brake circuit, the brake switch and the brake resistor can be connected in series. Additionally or alternatively, in the brake circuit, the brake switch and the battery can also be connected in series. The term "battery" can be used synonymously with "accumulator." The battery can be rechargeable and / or replaceable and / or a battery pack and / or a traction battery, particularly for supplying the machine tool with drive current and / or direct current. Additionally or alternatively, energy can be recuperated into the brake resistor, especially if it cannot be guaranteed that the specified braking duration can be maintained through recuperation into the battery. For further information, please refer to the relevant technical literature.

[0067] In a further development of the invention, the method, in particular the step of, actuating a source switch of the processing device, which is connected in series on an input side of the bridge circuit, into an open switching state before and concurrently with, in particular, the provision of the rotational speed and / or the detection of the current, and braking such that, in particular continuously, a drive current source is electrically disconnected from the bridge circuit. This enables braking. In particular, the actuating can be automatic and / or computer-implemented and / or carried out by means of the processing device. Additionally or alternatively, the source switch can be electrical, in particular a transistor, in particular a MOSFET. Furthermore, additionally or alternatively, the term "main switch" can be used synonymously with the term "source switch".Furthermore, or alternatively, the source switch can be different from the bridge circuit and / or the DC motor and / or the brake switch, and in particular from the load, especially comprising the braking resistor. Furthermore, or alternatively, the source switch can be connected between the drive current source and the bridge circuit, and in particular from the brake switch and / or the load, especially comprising the braking resistor, and / or an intermediate circuit and / or buffer capacitors of the machining tool. Furthermore, or alternatively, the drive current source can be a battery and / or be replaceable and / or supply the machining tool with drive current and / or DC current.Furthermore, or alternatively, the drive current source can be different from the bridge circuit and / or the DC motor and / or the brake switch, and in particular from the load, especially comprising the braking resistor. Furthermore, or alternatively, the method can include, in particular, the step of: switching the source switch to a closed state after braking, in particular until standstill, and / or, if the rotational speed is zero, in such a way, in particular continuously, that the drive current source is electrically connected to the bridge circuit. For further details, please refer to the relevant technical literature.

[0068] In a further development of the invention, the control of the bridge circuit comprises: Either, in particular, controlling all and / or the high-side switches of the bridge circuit to a closed switching state with a given duty cycle, in particular simultaneously, and thereby, in particular, continuously preventing all and / or the low-side switches of the bridge circuit from being controlled to a closed switching state. Or, alternatively, in particular, controlling all the low-side switches to the closed switching state with a given duty cycle, in particular simultaneously, and thereby, in particular, continuously preventing all the high-side switches from being controlled to the closed switching state. Or, alternatively...Alternatively, in particular all those that drive high-side switches to the closed state with a given duty cycle, especially simultaneously, and in time with this, in particular all those that drive low-side switches, especially continuously, not to the closed state, and in particular alternately or in time before and / or after this, in particular all those that drive low-side switches to the closed state with a given duty cycle, especially simultaneously, and in time with this, in particular all those that drive high-side switches, especially continuously, not to the closed state. In other words: Either clocking the high-side switches, and in particular not the low-side switches. Or clocking the low-side switches, and in particular not the high-side switches. Or clocking the high-side switches, and in particular not the low-side switches, and in particular alternating with this, clocking the low-side switches, and in particular not the high-side switches.In other words: Rectify via the diodes, especially the B6 diodes, and pulse the switching via the braking resistor. This, particularly the alternating switching, allows for good thermal distribution. Specifically, the phrase "to an open switching state" can be used synonymously with "not to a closed switching state."

[0069] In one embodiment of the invention, the control is performed alternately after an equal plurality of periods, in particular a minimum of 2 and / or a maximum of 8, in particular 4, periods. This allows for particularly simple control of the processing device. In particular, the plurality can be fixed, in particular predetermined. Additionally or alternatively, the periods can be periods of pulse duration modulation. Furthermore, additionally or alternatively, the term "clock" can be used synonymously with the term "period". Alternatively, the control can be performed alternately after, in particular exactly or only, 1 period or after each clock.

[0070] Alternatively, the control can be performed alternately after a specific time period, such as every 100 ms (milliseconds).

[0071] Alternatively, the control can be performed alternately and randomly.

[0072] In a further development of the invention, the control of the bridge circuit is carried out with exactly one or only one control pattern and / or not dependent on a rotor position parameter, representative of a position of one, in particular the, rotor of the DC motor and / or not with a counter-current braking control pattern. This enables a particularly high degree of simplicity in the method, and in particular in the processing device. In particular, the control pattern can be fixed, in particular predetermined, especially with a fixed period or a constant frequency of periods of pulse duration modulation. Additionally or alternatively, the term "commutation pattern" can be used synonymously with the term "control pattern". Furthermore, additionally or alternatively, the term "free" can be used synonymously with the formulation "not dependent". The rotor position parameter can be the position.Furthermore, or alternatively, the term "position" can be used synonymously with the term "location". Furthermore, or alternatively, the position can be a rotor position and / or an angular position. Furthermore, or alternatively, the processing device may or may not have a Hall sensor for the position. Furthermore, or alternatively, the term "without" can be used synonymously with "not with". Furthermore, or alternatively, a counter-current braking control pattern may require the position. Furthermore, or alternatively, at least one pulse and at least one pause in the control of the bridge circuit may or may not be synchronized, especially not with the rotational speed. For further information, please refer to the relevant technical literature.

[0073] In a further development of the invention, during braking by reducing the rotational speed, the duty cycle, in particular a value of the duty cycle, particularly from the value of the varied duty cycle, up to 1, particularly including, particularly if the rotational speed is greater than 0, particularly only, is increased, particularly monotonically and / or continuously, particularly continuously differentiable and / or without interruption. This enables the speed and / or simplicity of braking. In particular, a duty cycle having the value 1 can mean that all three phases are connected together, which corresponds to a short circuit, and / or that the control of the bridge circuit is carried out with a short-circuit braking control pattern. Additionally or alternatively, the duty cycle can have the value 1 from or upon reaching or falling below a limit value, in particular a predetermined, by the rotational speed.Furthermore, or alternatively, when braking by reducing the engine speed, the duty cycle may or may not need to be reduced. Furthermore, or alternatively, the phrase "without jumps" or the term "continuously variable" can be used synonymously with the term "continuously variable." Furthermore, or alternatively, the duty cycle can be increased based on an assignment, particularly a predefined one, such as a curve and / or a characteristic curve and / or a lookup table.

[0074] In a further development of the invention, the control of the bridge circuit is implemented such that a braking torque is maximally high, and in particular approximately constant, over a minimum of 60%, in particular 80%, and in particular 90% of a rotational speed range. This enables exceptionally fast braking. Specifically, the rotational speed range can extend from a braking start greater than 0 to a braking end equal to 0 and / or be a range of values. Additionally or alternatively, the control can be in the form of a control or regulation to achieve the maximum braking torque. Furthermore, additionally or alternatively, "approximately constant" can mean a deviation or variation of a maximum of 40%, in particular 20%, and in particular 10% of the braking torque from a maximum braking torque averaged over the range.

[0075] In a further development of the invention, the method comprises, in particular, the following steps: Detecting a number, in particular a plurality, of braking events, in particular until standstill, in particular within a specific time period, and / or a temperature value representative of a component of the processing device during braking, in particular during and / or after braking. Preventing an increase in rotational speed, in particular from zero, depending on whether a limit value is reached or exceeded by the detected number and / or the detected temperature value, in particular after braking. This prevents overheating of the component. In particular, the detection and / or the preventing function can be implemented automatically and / or by computer and / or by means of the processing device. Additionally or alternatively, the time period can be fixed, in particular predetermined.Furthermore, or alternatively, the temperature parameter can be the temperature itself. Furthermore, or alternatively, the component can include the braking resistance, in particular the braking resistance. Furthermore, or alternatively, the term "starting process" can be used synonymously with the phrase "increasing the speed." Furthermore, or alternatively, the term "threshold value" can be used synonymously with the term "limit value." Furthermore, or alternatively, the limit value can be fixed, in particular predetermined, and / or greater than 0. Furthermore, or alternatively, the locking mechanism can include: activating the brake switch in the closed switching state after braking in such a way, in particular continuously, that the load stresses and decelerates the DC motor.Furthermore, or alternatively, the locking mechanism can include: activating the source switch in the open switching state after braking, in particular continuously, such that the drive current source is electrically disconnected from the bridge circuit. Furthermore, or alternatively, the method, in particular the step of: enabling the increase in rotational speed depending on whether the limit value is undershot by the detected number and / or the detected temperature parameter, in particular after braking.

[0076] The electrically driven processing device according to the invention, and in particular the battery according to the invention, is specifically designed to carry out the method as described above. The processing device, and in particular the battery, can offer the same advantage(s) as described above for the method. In particular, the execution can be automatic. Additionally or alternatively, the terms "configured," "set up," or "provided for," or the English phrase "programmed to perform the function(s) of," can be used synonymously with the term "designed." Furthermore, additionally or alternatively, the processing device can include a control device, in particular an electrical one, for controlling the process, a supply device, in particular an electrical one, for supplying the process, and / or a detection device, in particular an electrical one, for detection.Furthermore, additionally or alternatively, the processing device, in particular the control device, the provision device and / or the acquisition device, may include a computing device and / or a processor and / or a microcontroller and / or a storage device and / or a computer.

[0077] BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Further advantages and aspects of the invention will become apparent from the claims and from the description of exemplary embodiments of the invention, which are explained below with reference to the figures. These figures show:

[0079] Fig. 1 shows a schematic perspective view of an electrically driven processing device according to the invention, and in particular of a battery according to the invention, for carrying out a method according to the invention for braking a rotating brushless DC motor of the processing device,

[0080] Fig. 2 shows a schematic view, in particular a circuit diagram or a

[0081] Circuit diagram of the processing device, and in particular of the battery,

[0082] Fig. 3 shows a flowchart or process diagram of the procedure,

[0083] Fig. 4 schematically shows graphs of a speed value representative of a DC motor speed and a duty cycle of a pulse duration modulation when controlling a bridge circuit of the processing device for electronic commutation of the DC motor as a function of the speed value over time.

[0084] Fig. 5 schematically shows graphs of the duty cycle of pulse duration modulation in the

[0085] Controlling the bridge circuit over time,

[0086] Fig. 6 schematically shows graphs of a field-generating current and a torque-generating current due to the control over time.

[0087] Fig. 7 schematically shows a graph of a braking torque for braking by actuation over time, and

[0088] Fig. 8 schematically shows a graph of phase current quantities representative of

[0089] Phase currents of the DC motor over time lead to a variation in the duty cycle, in particular to the provision of the speed magnitude.

[0090] DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0091] Figures 1 to 8 show an electrically driven machining device 1 according to the invention, and in particular a battery 7 according to the invention, for carrying out a method according to the invention for braking a rotating brushless DC motor 2 of the electrically driven machining device 1, in particular for bringing the DC motor 2 to a standstill. The DC motor 2 can be electronically commutated by means of a bridge circuit 3 of the machining device 1, in particular controlled as shown in Figure 2. The method comprises: braking the rotating DC motor 2 by varying a duty cycle D of a pulse duration modulation (PDM) when controlling the bridge circuit 3, wherein the duty cycle D has values ​​between 0 and less than 1 if the rotational speed n of the DC motor 2 is greater than 0, as shown in Figures 4 and 5.

[0092] The method additionally comprises: providing a rotational speed value nG representative of the rotational speed n, in particular repeatedly. Braking is performed by varying the duty cycle D as a function of the provided rotational speed value nG, as shown in the embodiments in Fig. 4 above and below.

[0093] Furthermore, additionally or alternatively, the control is carried out such that for a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a braking duration ZDb, in particular until standstill, the value of a field-generating current Id is at most 2 times as large, in particular a maximum of 1.5 times as large, in particular a maximum of equal to or smaller than the value of a torque-generating current Iq, as shown in Fig. 6.

[0094] Furthermore, or alternatively, the method, in particular the provision, comprises: acquiring a current value IG representative of a current I of the DC motor 2, in particular repeatedly, as shown in Fig. 8. Braking is performed by varying the duty cycle D as a function of the acquired current value IG. In particular, the provision of the speed value nG is performed as a function of the acquired current value IG.

[0095] In detail, the provision involves: Acquiring phase current quantities IGu, IGv, IGw representative of phase currents lu, Iv, Iw of the DC motor 2, in particular the time profiles of the phase current quantities IGu, IGv, IGw. Providing the speed quantity nG as a function of a time duration quantity ZDG representative of a time duration ZD between time points ZP, at which the values ​​of the acquired phase current quantities IGu, IGv, IGw are equal.

[0096] Furthermore, the method features: controlling the bridge circuit 3 with a fixed value of the duty cycle D of the pulse duration modulation PDM to provide the speed quantity nG and / or to detect the current quantity IG and, prior to braking, to vary the duty cycle D depending on the provided speed quantity nG and / or the detected current quantity IG, as shown in Figs. 3 to 5.

[0097] Furthermore, the method includes: controlling a brake switch 4 of the processing device 1, which is different from the bridge circuit 3, into a closed switching state to brake in such a way that a load 5 loads and brakes the DC motor 1, as shown in Figs. 2 and 3.

[0098] In detail, the load 5 includes a braking resistor 6 of the processing device 1. Specifically, a brake circuit consisting of the brake switch 4 and the brake resistor 6 is connected in parallel to the bridge circuit 3 on either an input side 3I or an output side 30. Additionally or alternatively, the load 5 includes a battery 7. Specifically, a brake circuit consisting of the brake switch 4 and the battery 7 is connected in parallel to the bridge circuit 3 on either the input side 3I or the bridge circuit 3.

[0099] The method further comprises: controlling a source switch 8 of the processing device 1, which is connected to one, in particular the, input side 3I of the bridge circuit 3, into an open switching state open in time before and with the braking such that a drive current source 9 is electrically disconnected from the bridge circuit 3.

[0100] Furthermore, controlling the bridge circuit 3 involves: Either controlling the high-side switches 10, in particular 10u, 10v, 10w, of the bridge circuit 3 with duty cycle D to a closed switching state, and thus preventing the low-side switches 11, in particular 11u, 11v, 11w, of the bridge circuit 3 from being controlled to a closed switching state, as shown in the embodiment of Fig. 3 on the right and Fig. 5 above or 5a. Or controlling the low-side switches 11 with duty cycle D to the closed switching state, and thus preventing the high-side switches 10 from being controlled to the closed switching state, as shown in the embodiment of Fig. 3 on the left.Or, the highside switches 10 with duty cycle D are controlled to the closed switching state, and thus the lowside switches 11 are not controlled to the closed switching state at the same time, and thus the lowside switches 11 are alternately controlled to the closed switching state with duty cycle D, and thus the highside switches 10 are not controlled to the closed switching state at the same time, as shown in the embodiment of Fig. 3 middle and Fig. 5 bottom or 5b.

[0101] In detail, the control is carried out alternately after an equal plurality of, in particular a minimum of 2 and / or a maximum of 8, in particular 4, periods P.

[0102] Furthermore, the control of the bridge circuit 3 is carried out with exactly one control pattern AM and / or is not dependent on a rotor position variable representative of a rotor position of the DC motor and / or is not carried out with a counter-current braking control pattern. In addition, during braking by reducing the rotational speed n, the duty cycle D, in particular a value of the duty cycle D up to 1, especially if the rotational speed n is greater than 0, is increased, in particular monotonically and / or continuously, in particular continuously differentiable, as shown in Figures 4 and 5.

[0103] Furthermore, the control of the bridge circuit 3 is carried out in such a way that over a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a range Bn of the rotational speed a braking torque M is maximally large, in particular approximately constant, as shown in Fig. 7.

[0104] Furthermore, the method comprises: Detecting a number of braking cycles (AZ) of executions, in particular up to standstill, especially within a specific time period, and / or a temperature parameter (TG) representative of a temperature T of a component 12 of the processing device 1 during braking, especially during and / or after braking, as shown in Figures 2 and 3. Preventing an increase in rotational speed (n) depending on whether a limit value (GW) is reached or exceeded by the detected number of braking cycles (AZ) and / or the detected temperature parameter (TG), especially after braking.

[0105] As the exemplary embodiments shown and explained above clearly demonstrate, the invention provides an advantageous method for braking a rotating brushless DC motor of an electrically driven machining device and the advantageous electrically driven machining device, and in particular an advantageous battery, for carrying out the method, which have improved properties.

[0106] In addition to or as an alternative to the claims listed below under "Patent Claims", the following claims may also exist:

[0107] 1. A method for braking a rotating brushless DC motor (2) of an electrically driven machine tool (1), in particular for bringing the DC motor (2) to a standstill, wherein the DC motor (2) can be electronically commutated by means of a bridge circuit (3) of the machine tool (1), the method comprising: braking the rotating DC motor (2) by varying a duty cycle (D) of a pulse duration modulation (PDM) when controlling the bridge circuit (3), wherein the duty cycle (D) has values ​​between 0 and less than 1 if a rotational speed (n) of the DC motor (2) is greater than 0, wherein the control is carried out such that for a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a braking time (ZDb), in particular until standstill, a value of a field-generating current (Id) is at most twice as large, in particular a maximum of 1 5 times as big,in particular, at most equal to or smaller than the value of a torque-generating current (Iq).

[0108] 2. The method of claim 1, wherein the method comprises:

[0109] Providing a speed parameter (nG) representative of the speed parameter (n), in particular repeatedly, and wherein braking is performed by varying the duty cycle (D) depending on the provided speed parameter (nG).

[0110] 3. The method of claim 1 or 2, wherein the method comprises:

[0111] Acquiring a current quantity (IG) representative of a current (I) of the DC motor (2), in particular repeatedly, and wherein braking is performed by varying the duty cycle (D) depending on the acquired current quantity (IG), in particular wherein the speed quantity (nG) is provided depending on the acquired current quantity (IG). 4. Method according to claim 3, wherein the provisioning comprises: acquiring phase current quantities (IGu, IGv, IGw) representative of phase currents (Iu, Iv, Iw) of the DC motor (2), in particular of time profiles of the phase current quantities (IGu, IGv, IGw), and providing the speed quantity (nG) depending on the provision of a time duration quantity (ZDG) representative of a time duration (ZD) between time points (ZP) at which the values ​​of the acquired phase current quantities (IGu, IGv, IGw) are equal.

[0112] 5. Method according to one of claims 2 to 4, wherein the method comprises: controlling the bridge circuit (3) with a fixed value of the duty cycle (D) of the pulse duration modulation (PDM) to provide the rotational speed (nG) and / or to detect the current (IG) and, prior to braking, to vary the duty cycle (D) depending on the provided rotational speed (nG) and / or the detected current (IG).

[0113] 6. Method according to any one of claims 1 to 5, wherein the method comprises: controlling a brake switch (4) of the processing device (1), which is different from the bridge circuit (3), into a closed switching state (closed) to brake such that a load (5) loads and brakes the DC motor (2).

[0114] 7. Method according to claim 6, wherein the load (5) has a braking resistor (6) of the processing device (1), in particular wherein a brake series connection of the brake switch (4) and the brake resistor (6) is connected in parallel to the bridge circuit (3) on an input side (3I) or an output side (30) of the bridge circuit (3), and / or wherein the load (5) has a battery (7), in particular wherein a brake series connection of the brake switch (4) and the battery (7) is connected in parallel to the bridge circuit (3) on the input side (3I) of the bridge circuit (3).

[0115] 8. Method according to any one of claims 1 to 7, wherein the method comprises: controlling a source switch (8) of the processing device (1), which is connected in series on an input side (3I) of the bridge circuit (3), into an open switching state (open) before and during braking such that a drive current source (9) is electrically disconnected from the bridge circuit (3).

[0116] 9. A method according to any one of claims 1 to 8, wherein the control of the bridge circuit (3) comprises: either controlling the high-side switches (10) of the bridge circuit (3) with duty cycle (D) to a closed switching state and thereby preventing the low-side switches (11) of the bridge circuit (3) from being controlled to a closed switching state, or controlling the low-side switches (11) with duty cycle (D) to the closed switching state and thereby preventing the high-side switches (10) from being controlled to the closed switching state, or controlling the high-side switches (10) with duty cycle (D) to the closed switching state and thereby preventing the low-side switches (11) from being controlled to the closed switching state, and thereby alternately controlling the low-side switches (11) with duty cycle (D) to the closed switching state and thereby preventing the high-side switches (10) from being controlled to the closed switching state. Control the switching state. 10.Method according to claim 9, wherein the control is performed alternately after an equal plurality of, in particular a minimum of 2 and / or a maximum of 8, in particular 4, periods (P).

[0117] 11. Method according to any one of claims 1 to 10, wherein the control of the bridge circuit (3) is carried out with exactly one control pattern (AM) and / or not as a function of a rotor position variable representative of a position of a rotor of the DC motor and / or not with a counter-current braking control pattern.

[0118] 12. Method according to one of claims 1 to 11, wherein during braking with reduction of the rotational speed (n) the duty cycle (D), in particular a value of the duty cycle (D) up to 1, in particular if the rotational speed (n) is greater than 0, is increased, in particular monotonically and / or continuously, in particular continuously differentiable.

[0119] 13. Method according to one of claims 1 to 12, wherein the control of the bridge circuit (3) is carried out such that over a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a range (Bn) of the rotational speed (n) a braking torque (M) is maximally large, in particular approximately constant.

[0120] 14. Method according to any one of claims 1 to 13, wherein the method comprises: capturing a number (AZ) of executions of braking, in particular until standstill, in particular within a time period, and / or a temperature parameter (TG) representative of a temperature (T) of a component (12) of the processing device (1) for braking, in particular temporally during and / or after braking, and

[0121] Blocking an increase in rotational speed (n) depending on reaching or exceeding a limit value (GW) by the detected number (AZ) and / or the detected temperature parameter (TG), especially after braking.

[0122] 15. Electrically driven processing device (1), and in particular battery (7), for carrying out a method according to any one of claims 1 to 14.

[0123] In addition to the claims listed under "Patent Claims" below, the following claims may also be considered, either as additional or alternative claims:

[0124] 1. Method for braking a rotating brushless DC motor (2) of an electrically driven processing device (1), in particular for bringing the DC motor (2) to a standstill, wherein the DC motor (2) can be controlled to electronic commutation by means of a bridge circuit (3) of the processing device (1), wherein the method comprises:

[0125] Recording a current quantity (IG) representative of a current (I) of the DC motor (2), in particular repeatedly, and

[0126] Braking of the rotating DC motor (2) by varying the duty cycle (D) of a pulse-width modulation (PDM) when controlling the bridge circuit (3), wherein the duty cycle (D) has values ​​between 0 and less than 1, depending on the detected current (IG), if the rotational speed (n) of the DC motor (2) is greater than 0. 2. Method according to claim 1, wherein the control is carried out such that for a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a braking time (ZDb), in particular until standstill, the value of a field-generating current (Id) is at most 2 times as large, in particular a maximum of 1.5 times as large, in particular at most equal to or less than the value of a torque-generating current (Iq).

[0127] 3. The method of claim 1 or 2, wherein the method comprises:

[0128] Providing a rotational speed quantity (nG) representative of the rotational speed (n), in particular repeatedly, depending on the detected current quantity (IG), and wherein the braking is carried out by varying the duty cycle (D) depending on the provided rotational speed quantity (nG).

[0129] 4. Method according to claim 3, wherein the provision comprises: acquiring phase current quantities (IGu, IGv, IGw) representative of phase currents (lu, Iv, Iw) of the DC motor (2), in particular of time profiles of the phase current quantities (IGu, IGv, IGw), and providing the speed quantity (nG) as a function of providing a time duration quantity (ZDG) representative of a time duration (ZD) between time points (ZP) at which the values ​​of the acquired phase current quantities (IGu, IGv, IGw) are equal.

[0130] 5. Method according to any one of claims 1 to 4, wherein the method comprises: controlling the bridge circuit (3) with a fixed value of the duty cycle (D) of the pulse duration modulation (PDM) to provide the rotational speed (nG) and / or to detect the current (IG) and, prior to braking, to vary the duty cycle (D) depending on the provided rotational speed (nG) and / or the detected current (IG).

[0131] 6. Method according to any one of claims 1 to 5, wherein the method comprises: controlling a brake switch (4) of the processing device (1), which is different from the bridge circuit (3), into a closed switching state (closed) to brake such that a load (5) loads and brakes the DC motor (2).

[0132] 7. Method according to claim 6, wherein the load (5) has a braking resistor (6) of the processing device (1), in particular wherein a brake series connection of the brake switch (4) and the brake resistor (6) is connected in parallel to the bridge circuit (3) on an input side (3I) or an output side (30) of the bridge circuit (3), and / or wherein the load (5) has a battery (7), in particular wherein a brake series connection of the brake switch (4) and the battery (7) is connected in parallel to the bridge circuit (3) on the input side (3I) of the bridge circuit (3).

[0133] 8. A method according to any one of claims 1 to 7, wherein the method comprises: controlling a source switch (8) of the processing device (1), which is connected in series on an input side (3I) of the bridge circuit (3), into an open switching state (open) before and during braking such that a drive current source (9) is electrically disconnected from the bridge circuit (3). 9.A method according to any one of claims 1 to 8, wherein the control of the bridge circuit (3) comprises: either controlling the high-side switches (10) of the bridge circuit (3) with duty cycle (D) to a closed switching state and thereby preventing the low-side switches (11) of the bridge circuit (3) from being controlled to a closed switching state, or controlling the low-side switches (11) with duty cycle (D) to the closed switching state and thereby preventing the high-side switches (10) from being controlled to the closed switching state, or controlling the high-side switches (10) with duty cycle (D) to the closed switching state and thereby preventing the low-side switches (11) from being controlled to the closed switching state, and thereby alternately controlling the low-side switches (11) with duty cycle (D) to the closed switching state and thereby preventing the high-side switches (10) from being controlled to the closed switching state. head towards.

[0134] 10. Method according to claim 9, wherein the control is performed alternately after an equal plurality of, in particular a minimum of 2 and / or a maximum of 8, in particular 4, periods (P).

[0135] 11. Method according to any one of claims 1 to 10, wherein the control of the bridge circuit (3) is carried out with exactly one control pattern (AM) and / or not as a function of a rotor position variable representative of a position of a rotor of the DC motor and / or not with a counter-current braking control pattern.

[0136] 12. Method according to one of claims 1 to 11, wherein during braking with reduction of the rotational speed (n) the duty cycle (D), in particular a value of the duty cycle (D) up to 1, in particular if the rotational speed (n) is greater than 0, is increased, in particular monotonically and / or continuously, in particular continuously differentiable.

[0137] 13. Method according to one of claims 1 to 12, wherein the control of the bridge circuit (3) is carried out such that over a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a range (Bn) of the rotational speed (n) a braking torque (M) is maximally large, in particular approximately constant.

[0138] 14. A method according to any one of claims 1 to 13, wherein the method comprises:

[0139] Recording a number (AZ) of braking executions, in particular until standstill, especially within a time period, and / or a temperature parameter (TG) representative of a temperature (T) of a component (12) of the processing device (1) for braking, in particular during and / or after braking, and

[0140] Blocking an increase in rotational speed (n) depending on reaching or exceeding a limit value (GW) by the detected number (AZ) and / or the detected temperature parameter (TG), especially after braking.

[0141] 15. Electrically driven processing device (1), and in particular battery (7), for carrying out a method according to any one of claims 1 to 14.

Claims

Patent claims 1. Method for braking a rotating brushless DC motor (2) of an electrically driven processing device (1), in particular for bringing the DC motor (2) to a standstill, wherein the DC motor (2) can be controlled to electronic commutation by means of a bridge circuit (3) of the processing device (1), wherein the method comprises: Providing a speed value (nG) representative of a speed (n) of the DC motor (2), in particular repeatedly, and Braking of the rotating DC motor (2) by varying a duty cycle (D) of a pulse duration modulation (PDM) when driving the bridge circuit (3), wherein the duty cycle (D) has values ​​between 0 and less than 1, depending on the provided speed quantity (nG), if the speed (n) is greater than 0.

2. Method according to claim 1, wherein the control is carried out such that for a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a braking time (ZDb), in particular until standstill, a value of a field-generating current (Id) is at most 2 times as large, in particular a maximum of 1.5 times as large, in particular a maximum equal to or smaller than a value of a torque-generating current (Iq).

3. Method according to claim 1 or 2, wherein the provision comprises: detecting a current quantity (IG) representative of a current (I) of the DC motor (2), in particular repeatedly, and providing the speed quantity (nG) as a function of the detected current quantity (IG).

4. Method according to claim 3, wherein the provision comprises: acquiring phase current quantities (IGu, IGv, IGw) representative of phase currents (lu, Iv, Iw) of the DC motor (2), in particular of time profiles of the phase current quantities (IGu, IGv, IGw), and providing the speed quantity (nG) as a function of providing a time duration quantity (ZDG) representative of a time duration (ZD) between time points (ZP) at which the values ​​of the acquired phase current quantities (IGu, IGv, IGw) are equal.

5. Method according to any one of claims 1 to 4, wherein the method comprises: controlling the bridge circuit (3) with a fixed value of the duty cycle (D) of the pulse duration modulation (PDM) to provide the rotational speed (nG) and / or to detect the current (IG) and, prior to braking, to vary the duty cycle (D) depending on the provided rotational speed (nG) and / or the detected current (IG).

6. Method according to any one of claims 1 to 5, wherein the method comprises: controlling a brake switch (4) of the processing device (1), which is different from the bridge circuit (3), into a closed switching state (closed) to brake such that a load (5) loads and brakes the DC motor (2).

7. Method according to claim 6, wherein the load (5) has a braking resistor (6) of the processing device (1), in particular wherein a brake series connection of the brake switch (4) and the brake resistor (6) is connected in parallel to the bridge circuit (3) on an input side (3I) or an output side (30) of the bridge circuit (3), and / or wherein the load (5) has a battery (7), in particular wherein a brake series connection of the brake switch (4) and the battery (7) is connected in parallel to the bridge circuit (3) on the input side (3I) of the bridge circuit (3).

8. Method according to any one of claims 1 to 7, wherein the method comprises: controlling a source switch (8) of the processing device (1), which is connected in series on an input side (3I) of the bridge circuit (3), into an open switching state (open) before and during braking such that a drive current source (9) is electrically disconnected from the bridge circuit (3).

9. A method according to any one of claims 1 to 8, wherein the control of the bridge circuit (3) comprises: either controlling the high-side switches (10) of the bridge circuit (3) with duty cycle (D) to a closed switching state and thereby not controlling the low-side switches (11) of the bridge circuit (3) to a closed switching state, or controlling the low-side switches (11) with duty cycle (D) to the closed switching state and thereby not controlling the high-side switches (10) to the closed switching state. or control the high-side switches (IO) with duty cycle (D) to the closed switching state (closed) and thus do not control the low-side switches (11) to the closed switching state at the same time, and thus alternately control the low-side switches (11) with duty cycle (D) to the closed switching state (closed) and thus do not control the high-side switches (10) to the closed switching state at the same time.

10. Method according to claim 9, wherein the control is performed alternately after an equal plurality of, in particular a minimum of 2 and / or a maximum of 8, in particular 4, periods (P).

11. Method according to any one of claims 1 to 10, wherein the control of the bridge circuit (3) is carried out with exactly one control pattern (AM) and / or not as a function of a rotor position variable representative of a position of a rotor of the DC motor and / or not with a counter-current braking control pattern.

12. Method according to one of claims 1 to 11, wherein during braking with reduction of the rotational speed (n) the duty cycle (D), in particular a value of the duty cycle (D) up to 1, in particular if the rotational speed (n) is greater than 0, is increased, in particular monotonically and / or continuously, in particular continuously differentiable.

13. Method according to one of claims 1 to 12, wherein the control of the bridge circuit (3) is carried out such that over a minimum of 60%, in particular a minimum of 80%, in particular a minimum of 90% of a range (Bn) of the rotational speed (n) a braking torque (M) is maximally large, in particular approximately constant.

14. A method according to any one of claims 1 to 13, wherein the method comprises: Recording a number (AZ) of braking executions, in particular until standstill, especially within a time period, and / or a temperature parameter (TG) representative of a temperature (T) of a component (12) of the processing device (1) for braking, in particular during and / or after braking, and Blocking an increase in rotational speed (n) depending on reaching or exceeding a limit value (GW) by the detected number (AZ) and / or the detected temperature parameter (TG), especially after braking.

15. Electrically driven processing device (1), and in particular battery (7), for carrying out a method according to any one of claims 1 to 14.

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