Electrical appliance and method

Abstract

The invention relates to an electrical appliance (1) in the form of an electrical tool (1A) or suction device (1B), comprising a drive unit (2) and a battery (3), which provides a battery current (4) for operating the drive unit (2), and a battery current regulator unit (17), which is designed to carry out battery current regulation of the battery current (4) and, as part of battery current regulation, to set a rotation speed setpoint value (19) for the drive unit (2) such that the battery current (4) does not exceed a battery current limit value (20).

Description

[0001]

[0002] December 21, 2023

[0003] Festool GmbH , Wertstraße 20 , 73240 Wendlingen am Neckar

[0004] Electrical device and process

[0005] The invention relates to an electrical device which is designed as a power tool or as a vacuum cleaner, comprising a drive unit and a battery which provides a battery current for operating the drive unit.

[0006] One object of the invention is to avoid interruptions in the operation of the electrical device.

[0007] The object is achieved by an electrical device according to claim 1. The electrical device comprises a battery current control unit which is designed to carry out battery current control of the battery current and, as part of the battery current control, to set a speed setpoint for the drive unit such that the battery current does not exceed a battery current limit value.

[0008] In a conventional electrical device without the battery current control according to the invention, an increase in the torque of the drive unit (e.g. required to achieve a desired speed) leads to a corresponding increase in the battery current. This can result in the battery current reaching or exceeding the battery current limit, whereupon the conventional electrical device stops supplying power to the drive unit and thus interrupts the operation of the electrical device. In contrast, the electrical device according to the invention, within the scope of the battery current control, sets the speed setpoint (e.g. by a corresponding reduction in the speed setpoint) so that the battery current does not exceed (and in particular does not reach) the battery current limit. In particular, the electrical device reduces the speed setpoint in response to the battery current approaching the battery current limit.By reducing the speed setpoint, a further increase in the torque to be provided by the drive unit (and thus a further increase in the power required for this) can be achieved.

[0009] Battery current) can be reduced or avoided, so that the battery current is prevented from exceeding (or reaching) the battery current limit. This can, in particular, prevent the power supply to the drive unit from being switched off—and thus interrupting the operation of the electrical device. Operation of the electrical device can, in particular, continue at a reduced speed.

[0010] Advantageous further training is the subject of the dependent claims.

[0011] The invention further relates to a method for operating the electrical device, comprising the step of carrying out the battery current regulation.

[0012] Further exemplary details and exemplary

[0013] Embodiments are explained below with reference to the figures.

[0014] Figure 1 is a schematic representation of an electrical device designed as a power tool,

[0015] Figure 2 is a schematic representation of an electrical device designed as a vacuum cleaner, Figure 3 is a block diagram of a control device with a battery current control unit and a speed control unit,

[0016] Figure 4 is a block diagram of a battery current regulator,

[0017] Figure 5 is a diagram showing the time course of a torque , a battery current and a speed , in the case that the speed is not reduced, and

[0018] Figure 6 is a diagram showing the time course of a torque, a battery current and a speed in the case that the speed is reduced.

[0019] Figure 1 shows an electrical device 1 embodied as an electrical tool 1A. The electrical tool 1A is embodied as a sawing device, but can alternatively also be embodied as another electrical tool, for example, a sander. Figure 2 shows an electrical device 1 embodied as a vacuum cleaner 1B, in particular as a vacuum cleaner.

[0020] Unless otherwise stated, the following explanations refer expediently both to the electrical device 1 designed as an electrical tool 1A and to the electrical device 1 designed as a vacuum cleaner 1B.

[0021] The electrical device 1 is preferably a semi-stationary machine. In particular, the electrical device 1 is dimensioned such that it can be carried manually by a person, for example, to transport the electrical device 1 to a site of use. The electrical device 1 comprises a drive unit 2 and a battery 3, which provides a battery current 4 for operating the drive unit 2. The drive unit 2 expediently comprises an electric motor 7 and / or power electronics 8. The electric motor 7 is preferably designed as a brushless DC motor.

[0022] In the power tool 1A, the drive unit 2 (preferably the electric motor 7) serves in particular to drive a tool 5, for example, a saw blade or a grinding element. In the vacuum cleaner 1B, the drive unit 2 (preferably the electric motor 7) serves in particular to drive a blower unit 9, for example, a fan unit, in order to generate a vacuum.

[0023] The battery 3 is designed, for example, as a battery module and is, in particular, replaceable, in particular replaceable without tools. The battery current 4 is expediently the current flowing out of the battery 3, in particular the current flowing from the battery 3 to the drive unit 2, for example the power electronics 8. For example, the battery current 4 is the entire current flowing out of the battery 3. The battery current 4 is, in particular, a direct current. In this context, a direct current is a current that flows in only one direction, but can expediently vary in its current strength.

[0024] The power electronics 8 generates one or more motor currents 10 on the basis of the battery current 4, which are expediently fed to the electric motor 2 in order to drive the electric motor 2. Each motor current 10 is expediently an alternating current. The motor currents 10 can also be referred to as phase currents. The power electronics 8 expediently generates three, in particular only three, motor currents 10 on the basis of the battery current 4. In particular, due to the fact that several motor currents 10 are generated, each of the motor currents 10 is expediently different from the battery current 4. In particular, none of the motor currents 10 is equal to the battery current 4. For example, the current intensity of each motor current 10 is (in particular constantly) different from the current intensity of the battery current (in particular when the current intensity of the battery current is not equal to zero).

[0025] The electrical device 1 exemplarily comprises a computer unit 12, in particular a microprocessor, for example a microcontroller, which expediently serves to provide, in particular to calculate, a control signal 16 for the drive unit 2, in particular the power electronics 8. Expediently, the power electronics 8 provides the motor currents 10 in accordance with the control signal 16 and expediently draws the battery current 4 required for these motor currents 10 from the battery 3. The control signal 16 expediently specifies the torque to be provided by the drive unit 2 and / or one or more motor currents 10 to be supplied to the drive unit 2.

[0026] The electrical device 1 comprises, by way of example, an operating device 11 which, for example, comprises one or more operating elements, for example a button and / or a rotary dial, and / or a display. A reference speed value 22 can preferably be set via the operating device 11 by means of a user input. For example, a user can make a user input via the operating device 11, for example enter the reference speed value 22. Expediently, the computer unit 12 calculates the control signal 16 taking into account the user input, in particular the entered reference speed value 22. For example, the computer unit 12 calculates the control signal 16 such that an actual speed value 23 (in particular of the electric motor 7) changes towards a target speed value 19 calculated on the basis of the reference speed value 22.

[0027] The electrical device 1 expediently comprises an electrical device housing 6, which in particular represents the outer housing of the electrical device 1. The drive unit 2, the battery 3, and / or the computer unit 12 are expediently arranged in the electrical device housing 6. The operating device 11 is expediently arranged on the outside of the electrical device housing 6.

[0028] In the electrical device 1 embodied as a power tool 1A, the electrical device housing 6 is expediently designed as a support structure. For example, the electrical tool 1A can be placed on a support with the underside of the electrical device housing 6. The top side of the electrical device housing 6 serves, for example, as a support surface for a workpiece to be machined with the tool 5.

[0029] In the electrical appliance 1 designed as a vacuum cleaner 1B, a particle collection container 13, which is designed, for example, as a vacuum cleaner bag, is expediently arranged in the electrical appliance housing 6. The vacuum cleaner 1B expediently has a hose connection 14 to which a suction hose can be connected (or is connected). During operation, the vacuum cleaner 1B generates a negative pressure by means of the drive unit 2, via which particles, in particular dust, are sucked from outside via the suction hose and / or the hose connection 14 into the particle collection container 13.

[0030] Figure 3 shows a block diagram of a controller device 15 of the electrical device 1. The controller device 15 is implemented, for example, as software, which is executed in particular by the computer unit 12. The controller device 15 expediently serves to provide, in particular to calculate, the control signal 16. By way of example, the controller device 15 calculates the control signal 16 on the basis of an actual battery current value 21, which maps a current value of the battery current 4, a battery current limit value 20, which expediently indicates a maximum permissible value of the battery current 4, the reference speed value 22, which, for example, specifies a desired speed for the drive unit 2 (for example in accordance with the user input entered using the operating device 11) and / or an actual speed value 23, which maps a current speed of the drive unit 2 (in particular of the electric motor 7).For example, the controller device 15 receives the actual battery current value 21, the battery current limit value 20, the reference speed value 22, and / or the actual speed value 23. For example, the electrical device 1 calculates or measures the actual battery current value and / or the actual speed value 23. The battery current limit value 20 is expediently stored in the electrical device 1, for example in the computer unit 12 and / or in the battery 3, in particular in a non-volatile memory.

[0031] By way of example, the controller device 15 has a battery current controller unit 17 and / or a speed controller unit 18. The battery current controller unit 17 comprises, by way of example, a battery current controller 25 and / or a multiplier 26. By way of example, the battery current controller 25 calculates a scaling factor 24 on the basis of the battery current limit value 20 and the battery current actual value 21. The multiplier 26 expediently multiplies the reference speed value 22 by the scaling factor 24 in order to obtain the speed setpoint value 19. The speed controller unit 18 calculates the control signal 16 on the basis of the speed setpoint value 19 and the speed actual value 23, in particular in such a way that the speed actual value 23 changes towards the speed setpoint value 19.

[0032] The battery current regulator unit 17 is designed to carry out battery current regulation of the battery current 4. The battery current regulator unit 17 sets the speed setpoint 19 for the drive unit 2 as part of the battery current regulation such that the battery current 4 does not exceed the battery current limit 20. Preferably, the speed regulator unit 18 is designed to control the drive unit 2 with the control signal 16 in accordance with the speed setpoint 19. The drive unit 2 is expediently designed to draw the battery current 4 from the battery 3 in accordance with the control signal 16.

[0033] The control objective of the battery current control is in particular to prevent the actual battery current value 21 from exceeding the battery current limit value 20. For this purpose, the battery current control unit 17 continuously compares the actual battery current value 21 with the battery current limit value 20 and, on the basis of this comparison (in particular continuously), adjusts the speed setpoint value 19. The adjusted speed setpoint value 19 affects the control signal 16, which in turn determines the battery current 4 and thus the actual battery current value 21. The speed control unit 18 is expediently designed to reduce the speed setpoint value 19 on the basis of a comparison of the actual battery current value 21 with the battery current limit value 20 such that the battery current 4 does not exceed the battery current limit value 20.In particular, the battery current control unit 17 reduces the speed setpoint 19 in response to a battery current actual value approaching the battery current limit value 20, in order to thereby cause the battery current actual value 21 to increase less or not increase or decrease further.

[0034] The battery current control will be explained in more detail with reference to Figures 5 and 6.

[0035] Figure 5 shows a diagram with time profiles of the speed setpoint 19, the battery current limit value 20, the battery current 4 and a torque 27, specifically for a (hypothetical) case in which the described battery current control is not carried out and / or the speed setpoint 19 is not reduced. The torque 27 is the torque that the electric motor 7 must or should provide in order to reach the speed setpoint 19. By way of example, the speed setpoint 19 is kept constant and an increasing torque 27 of the electric motor 7 (for example due to an increasing load) leads to an increasing battery current 4, which reaches and exceeds the battery current limit value 20. Optionally, the electrical device 1 detects that the battery current 4 reaches or exceeds the battery current limit value 20 and, in response thereto, stops the power supply to the drive unit 2.

[0036] Figure 6 shows a diagram with time profiles of the speed setpoint 19, the battery current limit value 20, the battery current 4 and the torque 27, specifically for the case in which the described battery current control is carried out and / or the speed setpoint 19 is reduced. In response to the battery current 4 approaching the battery current limit value 20 (for example due to an increasing load on the drive unit 2 and a concomitant increase in the torque 27 of the drive unit 2), the controller device 15 reduces the speed setpoint 19 such that the battery current 4 does not exceed the battery current limit value 20, for example in such a way that the battery current 4 remains directly below and / or at the battery current limit value 20.

[0037] The torque 27 results, for example, from the phase currents of the electric motor 7. For example, the torque 27 continues to increase even if the battery current 4 is regulated to the battery current limit value 20. By reducing the speed setpoint 19, the power is expediently kept constant as the torque 27 increases; therefore, the battery current 4 does not increase any further at a constant battery voltage. The electronics, in particular the power electronics 8, expediently behave like a step-down converter. For example, the phase voltage is reduced by reducing the speed. Since the power at the electric motor 7 expediently remains the same, the phase current increases and hence also the torque 27.

[0038] In particular, when the electric motor 7 is designed as a brushless DC motor, the torque 27 can increase despite a decreasing speed, especially at constant power.

[0039] The speed setpoint 19 expediently serves as the manipulated variable of the battery current control and the battery current 4 is expediently the controlled variable of the battery current control. The battery current control limits the battery current 4 to or immediately below the battery current limit value 20. If the battery current 4 would exceed the battery current limit value 20 without the battery current control (i.e. e.g. in the case that a battery current 4 greater than the battery current limit value 20 would be required to reach the reference speed value 22), the battery current control expediently regulates the battery current 4 to or immediately below the battery current limit value 20. If the battery current 4 would remain below the battery current limit value 20 without the battery current control (e.g. in the case that a battery current 4 less than the battery current limit value 20 is sufficient to reach the reference speed value 22), the battery current control preferably does not influence the battery current 4.

[0040] The battery current regulator unit 17 is preferably designed to provide, in particular to calculate, the scaling factor 24 based on a comparison of the actual battery current value 21 with the battery current limit value 20, and to provide, in particular to calculate the speed setpoint 19 on the basis of the scaling factor 24. The scaling factor 24 can, for example, assume a value between a minimum scaling factor value, for example 0, and a maximum scaling factor value, for example 1. The scaling factor 24 calculated by the battery current regulator unit 17 is preferably smaller the higher the actual battery current value 21 is and / or the closer the actual battery current value 21 approaches the battery current limit value 20. The battery current regulator unit 17 expediently calculates the scaling factor 24 continuously.

[0041] Preferably, the battery current regulator unit 17 is configured to scale the reference speed value 22 according to the scaling factor 24 in order to provide, in particular to calculate, the speed setpoint 19. For example, the battery current regulator unit 17 multiplies the reference speed value 22 by the scaling factor 24 in order to calculate the speed setpoint 19.Preferably, the battery current regulator unit 17 is designed to provide the reference speed value 22 as the speed setpoint 19 in response to the actual battery current value 21 being less than the battery current limit value 20 (for example by the battery current regulator unit 17 setting the scaling factor 24 to the value 1) and / or to provide a speed value that is less than the reference speed value 22 as the speed setpoint 19 in response to the actual battery current value 21 being equal to the battery current limit value 20 (for example by the battery current regulator unit 17 setting the scaling factor 24 to a value less than 1 and expediently greater than 0).

[0042] The battery current controller 25 is preferably designed as a proportional-integral controller - i.e. as a PI controller. The battery current controller 25 is particularly designed to calculate the scaling factor 24 based on the battery current limit value 20 and the battery current actual value 21. For example, the battery current controller 25 calculates a proportional component and an integral component based on a difference between the battery current limit value 20 and the battery current actual value 21 and calculates the scaling factor 24 based on the proportional component and the integral component, in particular based on a sum of the proportional component and the integral component.

[0043] Figure 5 shows an exemplary implementation of the battery current regulator 25 .

[0044] The battery current regulator 25 exemplarily comprises a differential element 28 which is designed to form a difference between the battery current limit value 20 and the battery current actual value 21 and to provide it as a differential signal 29. The battery current regulator 25 preferably further comprises a first multiplier 30 which is designed to multiply the differential signal by a first constant in order to calculate a first proportional signal 31 which expediently represents the proportional component. The battery current regulator 25 expediently further comprises a second multiplier 32 which is designed to multiply the differential signal 29 by a second constant in order to calculate a second proportional signal 33. The first constant and the second constant are expediently stored in the computer unit 12 , in particular in a non - volatile memory .The battery current regulator 25 expediently further comprises a first summation element 34 which is designed to add the second proportional signal 33 and a fed-back limited integral signal 35 in order to calculate an integral signal 36. The fed-back limited integral signal 35 can also be referred to as a delayed limited integral signal. The battery current regulator 25 expediently further comprises a first limiting element 37 which is designed to limit the integral signal 36 in order to calculate a limited integral signal 41. Alternatively, the integral component can be limited via an anti-wind-up. The battery current regulator 25 preferably further comprises a delay element 42 which is designed to delay the limited integral signal 41, in particular by one step - that is to say in particular by one sample value of the integral signal 41 - in order to calculate the fed-back limited integral signal 35.The battery current regulator 25 expediently further comprises a second summation element 38, which is designed to add the limited integral signal 41 and the first proportional signal 31 in order to calculate an addition signal 39. The battery current regulator 25 expediently further comprises a second limiting element 40, which is designed to limit the addition signal 39 in order to calculate the scaling factor 24.

[0045] The electrical device 1 is preferably designed to recognize a type of rechargeable battery 3 and to set the battery current limit value 20 (to be used in particular for battery current regulation) according to the type of rechargeable battery 3. For example, the rechargeable battery 3 has type information which is stored in particular in a memory of the rechargeable battery 3, and the electrical device 1 is expediently designed to read the type information from the memory and to set the battery current limit value 20 on the basis of the type information. For example, the electrical device 1 has limit value data which assign a respective battery current limit value 20 to a plurality of type information items, and the electrical device 1 is designed to set the battery current limit value 20 using the limit value data. The limit value data is, for example, a look-up table.

[0046] Preferably, the electrical device 1, in particular the computer unit 12, is configured to calculate the actual battery current value 21. The actual battery current value 21 is expediently not measured. In particular, the electrical device 1 does not have a sensor for directly measuring the actual battery current value 21.

[0047] The electrical device 1 is preferably designed to calculate the actual battery current value 21 for the battery current control on the basis of an electrical power consumed by the drive unit 2 (in particular the electric motor 7). For example, the electrical device 1 is designed to calculate the actual battery current value 21 as a division of a sum of the electrical power consumed by the electric motor 7 and the electronic power consumed by the power electronics 8 (and in particular the computer unit 12) by a battery voltage of the battery 3. The electrical device 1, in particular the computer unit 12, is preferably designed to calculate the actual battery current value 21 on the basis of the motor currents 10 (in particular transformed according to the Clarke transformation), the motor voltages of the electric motor 7 (in particular transformed according to the Clarke transformation), a battery voltage and preferably an electronic power.For example, the electrical device 1, in particular the computer unit 12, is designed to calculate the actual battery current value 21 according to the following equation:.

[0048] I D C is the actual battery current value 21 . I aip h a and Ibeta are the motor currents of the electric motor 7 transformed according to the Clarke transformation. U aipha and U beta are the motor voltages of the electric motor 7 transformed according to the Clarke transformation. P Electronics i st the electronic power. P Electronics is in particular that portion of the power provided by the battery 3 (in particular the battery current 4) that is not supplied to the electric motor 7; for example, P Electronics is the power consumed by the power electronics 8, the computer unit 12 and / or the operating device 11. U DC is the battery voltage of battery 3 .

[0049] The electrical device 1 is expediently designed to determine three motor currents 10 for calculating the actual battery current value 21, which are to be referred to below as lu, Iv and Iw. lu, Iv and Iw are the phase currents of the electric motor 7. For example, the electrical device 1 is designed to measure the three motor currents lu, Iv and Iw or to measure two of these three motor currents and to calculate the third motor current on the basis of the two measured motor currents, in particular on the basis of the fact that the sum of the three motor currents lu, Iv and Iw is zero. The electrical device 1, in particular the computer unit 12, expediently transforms the three motor currents lu, Iv and Iw into an alpha-beta coordinate system (in particular using the Clarke transformation) in order to aipba and / ieta to obtain .

[0050] The electrical device 1 is expediently designed to determine three motor voltages for calculating the actual battery current value 21, which will be referred to below as Uu, Uv and Uw. Uu, Uv and Uw are the phase voltages of the electric motor 7. Preferably, the electrical device 1 is designed to measure the three motor voltages and (in particular using the Clarke transformation) to convert them into U alpha and U beta to convert .

[0051] Furthermore, the electrical device 1 can be designed to be directly U aipfia and U beta For example, the electrical device 1 is designed to calculate a voltage amplitude as the product of the intermediate circuit voltage and the modulation, and U aipba as the product of the voltage amplitude and the cosine of the control angle, and U betaas the product of the voltage amplitude and the sine of the control angle.

[0052] Furthermore, the electrical device 1 can be designed to calculate the actual battery current value 21 on the basis of the phase currents Iu, Iv and Iw and the duty cycle. For example, the electrical device 1 is designed to calculate the actual battery current value 21 as the phase current Iu at a modulation level of 100% and / or to calculate the actual battery current value 21 as the sum of the phase currents Iv and Iw. Furthermore, the electrical device 1 can be designed to take the duty cycle into account when calculating the actual battery current value 21 at a modulation level of less than 100%. The electrical device 1 is preferably designed to calculate the actual battery current value 21 using the on-times of phase currents of the drive unit 2. The electrical device 1 is expediently designed to calculate the actual battery current value 21 as the product of the phase current lu and the associated duty cycle phase u, in particular in the event that the phase current lu is measured as a positive current.The duty cycle phase u is, in particular, an on-time of a switch via which the phase current lu is supplied to the electric motor 7. In particular, if the phase currents Iv and Iw are measured as negative currents, the electrical device 1 calculates the actual battery current value 21, in particular, as follows:

[0053] I_DC = I_V * ( l -Dutycycle_Phase_V) + I_W * ( 1-Dutycycle_Phase_W)

[0054] I_DC is the actual battery current value 21, I_V is the phase current Iv, “l-Dutycycle_Phase_V” is the on-time of a switch through which the phase current Iv is discharged from the electric motor 7, and “l-Dutycycle_Phase_W” is the on-time of a switch through which the phase current Iw is discharged from the electric motor 7.

Claims

Claims 1. Electrical device (1) which is designed as an electric tool (1A) or as a vacuum cleaner (1B), comprising a drive unit (2) and a battery (3) which provides a battery current (4) for operating the drive unit (2), as well as a battery current regulator unit (17) which is designed to carry out a battery current regulation of the battery current (4) and, as part of the battery current regulation, to set a speed target value (19) for the drive unit (2) such that the battery current (4) does not exceed a battery current limit value (20).

2. Electrical device (1) according to claim 1, further comprising a speed control unit (18) which is designed to control the drive unit (2) with a control signal (16) according to the speed setpoint (19), wherein the drive unit (2) is designed to draw the battery current (4) from the battery (3) according to the control signal (16).

3. Electrical device (1) according to claim 1 or 2, wherein the battery current control unit (17) is designed to reduce the speed setpoint (19) on the basis of a comparison of an actual battery current value (21) with the battery current limit value (20) such that the battery current (4) does not exceed the battery current limit value (20).

4. Electrical device (1) according to claim 3, wherein the battery current regulator unit (17) is designed to provide a scaling factor (24) according to the comparison of the battery current actual value (21) with the battery current limit value (20) and to provide the speed setpoint value (19) on the basis of the scaling factor (24).

5. Electrical device (1) according to claim 4, wherein the battery current regulator unit (17) is designed to scale a reference speed value (22) according to the scaling factor (24) in order to provide the speed setpoint value (19).

6. Electrical device (1) according to claim 5, further comprising an operating device (11) via which the reference speed value (22) can be set by means of a user input.

7. Electrical device (1) according to one of claims 3 to 6, wherein the battery current regulator unit (17) is designed to provide a / the reference speed value (22) as the speed setpoint value (19) in response to the battery current actual value (21) being less than the battery current limit value (20) and / or to provide a speed value which is less than the reference speed value (22) as the speed setpoint value (19) in response to the battery current actual value (21) being equal to the battery current limit value (20).

8. Electrical device (1) according to one of claims 4 to 7, wherein the battery current regulator unit (17) comprises a battery current regulator (25) which is designed as a proportional-integral regulator and is designed to calculate the scaling factor (24) on the basis of the battery current limit value (20) and the battery current actual value (21).

9. Electrical device (1) according to one of claims 4 to 8, wherein the battery current regulator (25) comprises: a differential element (28) designed to form a difference between the battery current limit value (20) and the battery current actual value (21) and to provide it as a differential signal (29), a first multiplier element (30) designed to multiply the differential signal (29) by a first constant to calculate a first proportional signal (31), a second multiplier element (32) designed to multiply the differential signal (29) by a second constant to calculate a second proportional signal (33), a first summation element (34) designed to add the second proportional signal (33) and a feedback limited integral signal (35) to calculate an integral signal (36), a first limiting element (37) which is designed to limit the integral signal (36) in order to calculate a limited integral signal (41),a second summation element (38) designed to add the limited integral signal (35) and the first proportional signal (31) to calculate an addition signal (39), and a second limiting element (40) designed to limit the addition signal (39) to calculate the scaling factor (24).

10. Electrical device (1) according to one of the preceding claims, wherein the electrical device (1) is designed as a sawing device or grinding device.

11. Electrical device (1) according to one of the preceding claims, wherein the electrical device (1) is designed to recognize a type of battery (3) and to set the battery current limit value (20) according to the type of battery (3).

12. Electrical device (1) according to one of the preceding claims, wherein the electrical device (1) is designed to calculate a / the actual battery current value (21) for the battery current control on the basis of an electrical power consumed by the drive unit (2).

13. Electrical device (1) according to one of the preceding claims, wherein the electrical device (1) is designed to calculate a / the actual battery current value (21) for the battery current control over one or more on times of one or more phase currents of the drive unit (2).

14. A method for operating an electrical device (1) according to one of claims 1 to 13, comprising the step of: carrying out the battery current control.

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