METHOD AND APPARATUS FOR ACTUATING AN ELECTRIC MOTOR, COFFEE MACHINE, COMPUTER PROGRAM PRODUCT AND COMPUTER-READABLE STORAGE MEDIUM

Abstract

A method for actuating an electric motor includes modulating a drive power provided to the electric motor by using a ramp function for a change in rotational speed of the electric motor from a starting rotational speed to a target rotational speed. The target rotational speed is only reached after at least 200 ms, starting from the starting rotational speed. An apparatus, a fully automatic coffee machine having the apparatus, a computer program product and a computer-readable storage medium are also provided.

Claims

1. A method for actuating an electric motor, the method comprising: using a ramp function to modulate a drive power provided to the electric motor, for changing a rotational speed of the electric motor from a starting rotational speed to a target rotational speed, causing the target rotational speed, starting from the starting rotational speed, to only be reached after at least 200 ms.

2. The method according to claim 1, which further comprises: establishing the drive power from a modulated voltage, and modulating the voltage by using the ramp function during a change, start up or braking of the rotational speed of the electric motor; within a plurality of predetermined periods, using voltage pulses having duty cycles based on the ramp function to drive the electric motor and modulating the duty cycles; for a DC voltage for driving the electric motor, performing a pulse width modulation, and using a duty cycle to indicate a ratio of a duration of the voltage pulses to a duration of a respective period, and for an AC voltage for driving the electric motor, performing a phase firing modulation or a phase cutting modulation, and characterizing a duty cycle by a phase angle at which the phase firing ends or the phase cutting begins.

3. The method according to claim 2, which further comprises: configuring the ramp function to cause the drive power to change steadily, increase steadily or decrease steadily; for starting up, at a beginning of the ramp function, beginning the duty cycle at a value greater than zero and ending the duty cycle at a value greater than 80%, and upon phase firing modulation, beginning the ramp function at a phase angle greater than 20?, and for braking, at the beginning of the ramp function, beginning the duty cycle at a value of less than 100% and ending the duty cycle at a value of less than 20%, and upon phase firing modulation, beginning the ramp function at a phase angle of less than 160? for a half wave, or 340? for a full wave.

4. The method according to claim 1, which further comprises: preventing the increase or decrease in the effective power provided to the electric motor from a start value to a predetermined target value Z from exceeding 5 Z per second, at least in a predetermined interval of the ramp function; and causing the predetermined interval of the ramp function to include at least a last quarter of the ramp function, or a second half, or an entirety of ramp function.

5. The method according to claim 1, which further comprises predetermining the ramp function and causing a time-discrete change in a phase firing, or regulating the ramp function based on sensor values during the actuation of the electric motor, or carrying out a PID-controlled change in the phase firing.

6. The method according to claim 1, which further comprises adjusting a total time length of the ramp function to be at least one of longer than 400 ms or shorter than 2 s.

7. The method according to claim 1, which further comprises at least one of selecting or configuring the ramp function by a user, and setting: at least one of a minimum or maximum phase firing, or a time for a total time length of the ramp function, or a form of the ramp function, or at least one of a minimum or maximum width of a duty cycle.

8. The method according to claim 1, which further comprises configuring the ramp function to optimize at least one of an electromagnetic compatibility or a serviceable life of the electric motor.

9. The method according to claim 1, which further comprises using the ramp function to control a change in the drive power from a start value to a target value, and configuring the ramp function to ensure that an increase or decrease in the drive power provided to the electric motor, from a start value to a predetermined target value Z, does not exceed 5 Z per second, at least in a predetermined interval of the ramp function.

10. The method according to claim 1, which further comprises: using the ramp function to perform both starting up of the electric motor and braking of the electric motor, during start-up the target rotational speed being higher than the starting rotational speed and the starting rotational speed being zero, and during braking the starting rotational speed corresponding to the target rotational speed during start-up, and during braking the target rotational speed corresponding to the starting rotational speed during start-up; after braking, performing a renewed start-up with a reverse direction of rotation being performed by using the ramp function, and only permitting the target rotational speed, starting from the starting rotational speed, to be reached after at least 200 ms for the renewed start-up.

11. An apparatus for actuating an electric motor, the apparatus configured to implement the method according to claim 1.

12. The apparatus according to claim 11, which further comprises a configuration interface configured to accept user input for configuring the ramp function by at least one of selecting or configuring the ramp function to set: at least one of a minimum or maximum phase firing, or a time for a total time length of the ramp function, or a form of the ramp function, or at least one of a minimum or maximum width of a duty cycle.

13. A fully automatic coffee machine, comprising an apparatus according to claim 11, the apparatus configured to actuate an electric motor of a grinder.

14. A non-transitory computer program product, comprising commands that, when executing a program on a computer, cause the computer to generate control signals for the modulation, by using the ramp function, of a drive power provided to an electric motor according to claim 1.

15. A computer-readable storage medium, comprising commands that, when executed by a computer, cause the computer to generate control signals for the modulation, by using the ramp function, of a drive power provided to an electric motor according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0042] FIG. 1 is a diagrammatic, elevational view of an example of a coffee machine;

[0043] FIG. 2 is a block diagram illustrating the execution of a method in accordance with the invention;

[0044] FIG. 3 is a diagram showing examples of ramp functions; and

[0045] FIG. 4 is a diagram showing an example of the speed change of an electric motor.

DETAILED DESCRIPTION OF THE INVENTION

[0046] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a fully automatic coffee machine 1. The coffee machine includes, in addition to other units that are required for the preparation of coffee, in particular the following components: [0047] a brewing unit 2 that is coupled to a grinder 2a, wherein the coffee powder from the grinder 2a is pressed in the brewing unit 2, [0048] a pump 3, through which water is pumped from a water tank 5 through a flow heater as a heating element 4 into the brewing unit 2, [0049] a selection unit 6 for manual selection by the operator and for specifying a desired type of coffee beverage and/or for selecting a grinding mode, [0050] a control facility 7 that is configured so as to control the preparation of a coffee beverage of the selected coffee beverage type K by the coffee machine 1, wherein the control facility contains an apparatus 10 in accordance with the invention, [0051] a computing unit 9 that is configured so as to calculate control data for the control facility 7, and [0052] a data interface 8 for establishing a data contact with the selection unit 6.

[0053] As a result, data for selecting the type of coffee beverage can be forwarded to the computing unit 9. The arrow from the selection unit 6 to the data interface 8 is intended to indicate the direction of the data flow. This data interface 8 is also configured so as to send control data (see second arrow) to a control facility 7 so as to control a preparation of a coffee beverage of the selected coffee beverage type by the coffee machine 1.

[0054] In order to prepare a coffee beverage, water is pumped from the water tank 5 by the pump 3 through the heating element 4, heated there to the target temperature, and, in the hot state, passes into the brewing unit 2, in which there is coffee powder, which has been ground by the grinder 2a that is driven by an electric motor E. This process of grinding is controlled by the control facility 7 (or the special apparatus 10) in the manner described below:

[0055] FIG. 2 illustrates a block diagram for the execution of a method in accordance with the invention for the actuation (corresponding to a control or regulation) of an electric motor of the grinder 2a, for example of the fully automatic coffee machine 1 that is illustrated in FIG. 1.

[0056] In step I, a selection of a coffee beverage is made by a user by using the selection unit 6.

[0057] In step II, a ramp function is selected. This can also be done by the user by using the selection unit 6, but a preconceived ramp function R or a ramp function R that is linked to the selected coffee beverage can also be used.

[0058] In step III, the electric motor E is actuated by the apparatus 10 based on the ramp function R. In this case, during the start-up of the electric motor E, a drive power is modulated by using the ramp function R so that the increase or decrease in the drive power that is provided to the electric motor E from a start value P.sub.S to a predetermined target value P.sub.Z does not exceed five times the target value per second, in other words, it lasts at least 200 ms. This is determined by the ramp function R. This is configured accordingly.

[0059] In step IV, coffee beans are ground into coffee powder by the grinder 2a that is driven by the electric motor E.

[0060] In step V, the desired coffee beverage is brewed from the ground coffee powder.

[0061] FIG. 3 illustrates examples of ramp functions R. On the left-hand side, an example of a ramp function R (solid line) can be seen, which acts directly on the drive power P. The ramp function has a moderate increase from the starting value P.sub.S (in this case zero) to the target value P.sub.Z, in contrast to the function that is indicated by the dashed line, which starts particularly steeply and reaches the target value P.sub.Z much earlier.

[0062] A further example of a ramp function R that acts on a phase angle W of a phase firing modulation is shown on the right-hand side. The example is started at a fairly large phase angle W, which means that the phase firing is large and thus the drive power P is small. The ramp function R ends with a phase angle W of zero, which means that the phase firing is small and thus the drive power P is large. The drive power P would correspond to the progression of the drive power P in the left-hand image. In this case, too, a curve is indicated by dashed lines, which would correspond to a steep progression of the drive power.

[0063] FIG. 4 shows an example of the rotational speed change of an electric motor E. A plot of the rotational speed D against the time t is shown. First, the rotational speed D increases from a starting rotational speed D.sub.S (in this case zero) to a target rotational speed D.sub.Z. This is done by the method in accordance with the invention and takes 400 ms in this case. The electric motor E now rotates in a first direction of rotation over a certain time, which is indicated in this case by broken the section of the line. During this time, the grinder of a coffee machine according to FIG. 1 would therefore run at normal rotational speed D. Then, in accordance with the method according to the invention, the electric motor E is braked back to the starting rotational speed D.sub.S (zero) within 400 ms and then restarted in the reverse direction of rotation, likewise in accordance with the method according to the invention, within 400 ms. This is represented by the progression of the line in the negative quadrant up to the negative target rotational speed D.sub.Z. The electric motor E can be controlled by using ramp functions R, as is illustrated in FIG. 3. The reversal of the direction of rotation can also be omitted and the motor can simply be started up and braked.

[0064] Since the above embodiments that are described in detail are examples, they can be modified to a large extent by a person skilled in the art in a conventional manner without departing from the scope of the invention. In particular, the specific embodiments of the apparatus or the method can also follow in a form other than that described herein. Furthermore, the use of the indefinite article a or an does not rule out that the relevant features can also be provided multiple times.

[0065] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention.

LIST OF REFERENCE NUMERALS

[0066] 1 Coffee machine [0067] 2 Brewing chamber [0068] 2a Grinder [0069] 3 Pump [0070] 4 Heating element [0071] 5 Water tank [0072] 6 Selection unit [0073] 7 Control facility [0074] 8 Data Interface [0075] 9 Computing unit [0076] 10 Apparatus [0077] D Rotational speed [0078] DS Starting rotational speed [0079] DZ Target rotational speed [0080] E Electric motor [0081] P Drive power [0082] PS Starting value [0083] PZ Target value [0084] R Ramp function [0085] W Phase angle