Household appliance and method for operating a household appliance

Abstract

The invention relates to a household appliance (1, 101) and a method for operating the household appliance (1, 101). The household appliance (1, 101) comprises a component (21, 102) and a regulated electric drive (40), the electric drive having: a permanently excited three-phase AC synchronous motor (36); an actuator, in particular configured as a converter (41) and used to control the three-phase AC synchronous motor (36); and a field-oriented control device (43) for controlling the actuator. The three-phase AC synchronous motor (36) comprises a stator (37) and a rotor (38) rotatably mounted relative to the stator (37) and is part of the component (21, 102) or is provided for driving the component (21, 102).

Description

Technical Field

[0001] The invention relates to a method for operating a domestic appliance and a corresponding domestic appliance, which comprises a field-oriented controlled electric drive. Background Art

[0002] DE 10 2017 211 217 A1 discloses a household refrigeration appliance, which has a refrigerant circuit with a compressor and a speed-regulated electric drive. The regulating device of the electric drive is a field-oriented regulating device, and the electric drive includes a converter and a permanently excited three-phase AC synchronous motor connected downstream of the converter, the three-phase AC synchronous motor is part of the compressor and is configured to drive the compressor. In order to start the compressor from the starting phase to the cooling phase, starting from the stopped state of the compressor, the three-phase AC synchronous motor is moved at a starting rated speed of a maximum of 5% of the rated speed assigned to the cooling phase until the piston of the compressor moves past the top dead center of the compressor. Subsequently, the three-phase AC synchronous motor is moved so that its rotor rotates at the rated speed assigned to the cooling phase for the cooling phase.

[0003] EP 10 2008 029 910 A1 discloses a domestic dishwasher having a pump and a field-oriented controlled electric drive comprising a converter and a permanently excited three-phase AC synchronous motor connected downstream of the converter, which drives the pump.

[0004] For example, it is known from DE 10 2016 210 443 A1 or DE 10 2017 213 069 A1 to superimpose a high-frequency voltage on the supply voltage of a three-phase AC synchronous motor, which high-frequency voltage causes the line current of the three-phase AC motor to The corresponding, superimposed high-frequency components of the three-phase AC motor are used to determine the angular position of the rotor relative to the stator of the three-phase AC motor. Summary of the invention

[0005] The object of the present invention is to propose an improved method for operating a household appliance, which has a speed-regulated electric drive, whose regulating device is a field-oriented regulating device, and whose electric motor is a permanently excited three-phase AC synchronous motor, which is part of a component of the household appliance or is configured to drive the component.

[0006] The object of the present invention is achieved by a method for operating a household appliance, the household appliance having a component and a regulated electric drive, the regulated electric drive having: a permanently excited three-phase AC synchronous motor; an actuator, in particular configured as a converter, for controlling the three-phase AC synchronous motor; and a field-oriented control device for controlling the actuator, wherein the three-phase AC synchronous motor comprises a stator and a rotor rotatably mounted relative to the stator and is part of the component or is provided for driving the component, the method comprising the following method steps:

[0007] During the start-up phase of the electric drive,

[0008] - a supply voltage generated by the actuator and provided for operating the three-phase AC synchronous motor is superimposed with a high-frequency voltage, whereby the line current of the three-phase AC synchronous motor has a corresponding high-frequency current component,

[0009] - from the line currents, a longitudinal current and a quadrature-axis current assigned to the three-phase AC synchronous motor are determined, the longitudinal current and the quadrature-axis current having a high-frequency current component corresponding to the high-frequency voltage,

[0010] - Determine the angular position of the rotor relative to the stator based on the high-frequency current components of the longitudinal and transverse currents, and

[0011] - increasing the speed of the three-phase AC synchronous motor until the three-phase AC synchronous motor reaches a predetermined limit speed by operating the regulated electric drive in a speed-controlled manner with the aid of a field-oriented control device and as a function of the angular position of the rotor relative to the stator, wherein the angular position of the rotor relative to the stator is determined with the aid of high-frequency current components of the longitudinal and transverse currents,

[0012] and, during an operating phase following the starting phase, the regulated electric drive is operated in a speed-regulated manner with the aid of a field-oriented control device and as a function of the angular position of the rotor relative to the stator, wherein the angular position of the rotor relative to the stator is determined with the aid of longitudinal and transverse currents of the three-phase AC synchronous motor and a mathematical model.

[0013] Another aspect of the present invention relates to a household appliance having a component and a regulated electric drive device, the regulated electric drive device having: a permanently excited three-phase AC synchronous motor; an actuator configured in particular as an inverter for controlling the three-phase AC synchronous motor; and a field-oriented control device for controlling the actuator, wherein the three-phase AC synchronous motor comprises a stator and a rotor rotatably supported relative to the stator and is part of the component or is configured to drive the component, and the household appliance is configured to perform the method according to the present invention.

[0014] Another aspect of the invention relates to a household appliance having a component and a regulated electric drive, the regulated electric drive having: a permanently excited three-phase AC synchronous motor; an actuator, in particular configured as a converter, for controlling the three-phase AC synchronous motor; and a field-oriented control device for controlling the actuator, wherein the three-phase AC synchronous motor comprises a stator and a rotor rotatably supported relative to the stator and is part of the component or is configured to drive the component, and the household appliance is configured to, during a starting phase of the electric drive,

[0015] - a supply voltage generated by the actuator and provided for operating the three-phase AC synchronous motor is superimposed with a high-frequency voltage, whereby the line current of the three-phase AC synchronous motor has a corresponding high-frequency current component,

[0016] - from the line currents, a longitudinal current and a quadrature-axis current assigned to the three-phase AC synchronous motor are determined, the longitudinal current and the quadrature-axis current having a high-frequency current component corresponding to the high-frequency voltage,

[0017] - Determine the angular position of the rotor relative to the stator based on the high-frequency current components of the longitudinal and transverse currents, and

[0018] - increasing the speed of the three-phase AC synchronous motor until the three-phase AC synchronous motor reaches a predetermined limit speed by operating the regulated electric drive in a speed-controlled manner with the aid of a field-oriented control device and as a function of the angular position of the rotor relative to the stator, wherein the angular position of the rotor relative to the stator is determined with the aid of high-frequency current components of the longitudinal and transverse currents,

[0019] Furthermore, during an operating phase following the starting phase, the regulated electric drive is operated in a speed-regulated manner with the aid of a field-oriented control device and as a function of the angular position of the rotor relative to the stator, wherein the angular position of the rotor relative to the stator is determined with the aid of longitudinal and transverse currents of the three-phase AC synchronous motor and a mathematical model.

[0020] The household appliance comprises a regulated electric drive, the electric motor of which is a three-phase AC synchronous motor with permanent magnet excitation, such as a brushless DC motor.

[0021] The electric drive device also includes an actuator, which controls the three-phase AC synchronous motor, that is, supplies the three-phase AC synchronous motor with a supply voltage. The supply voltage is a three-phase voltage, and the basic frequency of the three-phase voltage is set by a speed control device and a desired rated speed.

[0022] The actuator is, in particular, a converter which is preferably operated by means of pulse width modulation.

[0023] The regulating device of the regulated electric drive controls an actuator or a converter and is a field-oriented regulating device. The field-oriented regulating device usually forms a cascade structure with an internal current regulating loop, to which an external speed regulating loop is superimposed. Therefore, the field-oriented regulating device particularly comprises a cascade structure with an internal current regulating loop with a current regulator, to which an external speed regulating loop is superimposed. The current regulator is particularly a PI regulator, ie preferably a regulator with a proportional component and an integral component.

[0024] The field-oriented control device is preferably a discrete or digital field-oriented control device. The clock frequency or control frequency of the discrete or digital field-oriented control device and thus of the current regulator is preferably greater than 1 kHz, for example 4 kHz.

[0025] For the field-oriented control device, it is necessary to know the angular position of the rotor of the three-phase AC synchronous motor relative to the stator. In order to determine the angular position without sensors or detectors, the angular position can be determined based on the so-called longitudinal current and the quadrature current of the three-phase AC synchronous motor and known in principle to those skilled in the art, and a mathematical model, which can be calculated from the line current of the three-phase AC synchronous motor, and the mathematical model is also called an observer. Therefore, the angular position of the rotor relative to the stator is determined in particular without sensors.

[0026] However, when the speed of the three-phase AC synchronous motor is relatively low, it is possible that the evaluation of these currents cannot reliably determine the angular position of the rotor. Therefore, according to the present invention, during the starting phase of the electric drive, especially starting from a standstill, the supply voltage generated by the actuator and provided for operating the three-phase AC synchronous motor is superimposed with a high-frequency voltage, whereby the line current of the three-phase AC synchronous motor has a corresponding high-frequency current component. This is called "high frequency injection (HFI)" in English. As a result, the longitudinal current and the transverse current have corresponding high-frequency current components. Based on these high-frequency current components, even at relatively low speeds, the angular position of the rotor required for the field-oriented control device can be determined sensorlessly, and the speed of the three-phase AC synchronous motor can be increased during the starting phase until the three-phase AC synchronous motor reaches a predetermined limit speed, in which the regulated electric drive is operated in a speed-controlled manner by means of the field-oriented control device and according to the angular position of the rotor relative to the stator, wherein the angular position of the rotor relative to the stator is determined by means of the high-frequency current components of the longitudinal current and the transverse current.

[0027] Based on these high-frequency current components, the angular position of the rotor can be determined even without sensors when the three-phase AC synchronous motor is at a standstill.

[0028] The limiting speed is preferably between 600 and 1400 revolutions per minute, in particular around 1000 revolutions per minute.

[0029] The high-frequency voltage and therefore the high-frequency current component preferably has a frequency of more than 1 kHz, preferably more than 2 kHz.

[0030] During an operating phase following the starting phase, the regulated electric drive is operated in a speed-regulated manner with the aid of a field-oriented control device and as a function of the angular position of the rotor relative to the stator, wherein the angle of the rotor relative to the stator is determined with the aid of the longitudinal current and the transverse current of the three-phase AC synchronous motor and a mathematical model, i.e., during the operating phase, the angular position of the rotor is determined as a function of the longitudinal current and the transverse current of the driving three-phase AC synchronous motor and a mathematical model.

[0031] According to a preferred embodiment of the method according to the invention, the method includes generating a control signal for an actuator by superimposing a signal generated by a current regulator and assigned to a supply voltage with a signal assigned to a high-frequency voltage. Therefore, the household appliance according to the invention is preferably configured to generate a control signal for an actuator by superimposing a signal generated by a current regulator and assigned to a supply voltage with a signal assigned to a high-frequency voltage. These two signals can be added in a relatively simple manner, whereby the control element can generate a supply voltage for a three-phase AC synchronous motor superimposed with a high-frequency voltage based on the control signal in a relatively simple manner.

[0032] In a field-oriented control device, the line current of a three-phase AC motor is converted into a longitudinal current and a quadrature current. The longitudinal current and the quadrature current are used in a circuit control loop to obtain a signal assigned to the supply voltage for controlling the actuator. The longitudinal current and the quadrature current are respectively assigned to a current regulator. Preferably, the signal assigned to the high-frequency voltage is only superimposed on the signal generated by the current regulator assigned to the longitudinal current.

[0033] In the field-oriented control device, it can be provided that the setpoint value of the longitudinal current is equal to zero. Preferably, the field-oriented control device is based on the so-called maximum torque current ratio principle (maximum torque perampere Prinzip) in order to reduce the energy consumption of the electric drive and thus the household appliance, in particular in the case of different magnitudes of the longitudinal inductance and the transverse inductance of the three-phase AC synchronous motor. In this case, the setpoint value of the longitudinal current is not set to zero or a fixed value, but is determined based on the relationship between the longitudinal inductance and the transverse inductance and based on a signal determined by an external speed control circuit, which is associated with the torque to be applied by the three-phase AC synchronous motor. Since the relationship mentioned is nonlinear, the setpoint values ​​of the longitudinal current and the transverse current are preferably stored in a lookup table.

[0034] The signal associated with the high-frequency voltage can be sinusoidal, for example. The signal is preferably rectangular.

[0035] In the case of a discrete field-oriented control device, the current regulator is preferably operated at a regulator frequency, which is equal to the frequency of the high-frequency voltage or the signal assigned to the high-frequency voltage. In particular, it can also be provided that the frequency of the high-frequency voltage or the signal assigned to the high-frequency voltage is an integer multiple of the regulator frequency.

[0036] In order to obtain the high-frequency current components of the longitudinal and transverse currents in a relatively simple manner, the method according to the invention according to a preferred variant comprises: discretely measuring the longitudinal and transverse currents at a frequency twice the frequency of the high-frequency voltage at least during the starting phase, wherein the measurement clock is set so that in two measurements carried out one after the other, one measurement is carried out at the maximum value of the measured current and the other measurement is carried out at the minimum value of the measured current. Therefore, the household appliance according to the invention is configured according to a preferred embodiment so that it measures the longitudinal and transverse currents at a frequency twice the frequency of the high-frequency voltage at least during the starting phase, wherein the measurement clock is set so that in two measurements carried out one after the other, one measurement is carried out at the maximum value of the measured current and the other measurement is carried out at the minimum value of the measured current. The high-frequency current components of the longitudinal and transverse currents can then be determined by difference formation (Differenzbilden) of the respective currents measured in the two measurements carried out one after the other.

[0037] The domestic appliance is, for example, a domestic washing machine which has a rotatably mounted laundry drum as a component driven by an electric drive.

[0038] A domestic appliance is, for example, a domestic dishwasher which has a lye pump as the component.

[0039] Preferably, the component is a compressor comprising a compressor chamber and arranged for compressing a fluid.

[0040] One example of a domestic appliance having a compressor is a domestic laundry dryer which comprises a heat pump circuit including a compressor and a regulated electric drive.

[0041] Another example of a household appliance with a compressor is a household refrigeration appliance, which comprises: an insulated body with a coolable inner container, which delimits a coolable interior space provided for storing food; a refrigerant circuit provided for cooling the coolable interior space, which has a coolant as a fluid and a compressor; and a regulated electric drive.

[0042] The domestic refrigeration appliance comprises a heat-insulating body with an inner container, which delimits a coolable interior. The coolable interior is provided for storing food and is cooled by means of a refrigerant circuit.

[0043] The coolable interior space can preferably be closed by means of a door panel. The door panel is preferably pivotably mounted relative to an axis that preferably extends vertically. In the open state, the coolable interior space is accessible.

[0044] The refrigerant circuit itself is known in principle to the person skilled in the art and comprises a compressor and, in particular, a liquefier connected downstream of the compressor, a throttling device connected downstream of the liquefier and an evaporator arranged between the throttling device and the compressor.

[0045] Preferably, the compressor chamber of the compressor comprises an inlet and an outlet, a piston movably supported inside the compressor chamber, and a crankshaft. In this case, the rotor of the three-phase AC synchronous motor is coupled to the piston via the crankshaft, so that when the compressor is running, the piston can reduce the volume surrounded by the compressor chamber and the piston by means of the three-phase AC synchronous motor in order to compress the fluid, wherein the volume is minimum at a certain position of the piston relative to the compressor chamber, and the volume is maximum at another certain position of the piston relative to the compressor chamber. Such compressors are usually called reciprocating piston compressors. Preferably, the actuator can then be controlled at the beginning of the starting phase so that it moves the piston away from the determined position before starting in a speed-controlled manner.

[0046] During compressor operation and in the case of domestic refrigeration appliances, the three-phase AC synchronous motor is operated in particular at a rotational speed which is ascertained or predefined, for example, by an electronic control unit or a temperature control device of the domestic refrigeration appliance.

[0047] Reciprocating piston compressors have a characteristic torque curve. This torque curve can be related to the load point, but can also be related to the speed of the three-phase AC synchronous motor. The mechanical conditions of the compressor, such as the components of the compressor that rotate the inertia moment, can have an influence on the operation of the three-phase AC synchronous motor.

[0048] The volume is minimum at a certain position of the piston relative to the compressor chamber. This certain position is usually called the top dead center.

[0049] The volume is maximum at another determined position of the piston relative to the compressor chamber. This other determined position is usually referred to as the bottom dead center.

[0050] If the three-phase AC synchronous motor moves the piston from its determined position (that is, from its top dead center) to its other determined position (that is, to its bottom dead center), the capacity increases and the compressor draws in fluid through its inlet.

[0051] If the three-phase AC synchronous motor moves the piston from its other determined position (that is, from its bottom dead center) to its determined position (that is, to its top dead center), the volume decreases and the compressor compresses the fluid located in the compressor chamber until the outlet at the top dead center opens, so that the compressed fluid can reach the liquefier.

[0052] Thus, when the compressor or the rotor is started, the speed can be increased in a speed-controlled manner, so that only the torque actually required for the start can be provided. This prevents the risk of field release. In addition, the starting current can be limited to a minimum as a result, which can bring about energy advantages. Furthermore, if necessary, a lower maximum load on the converter, in particular on its final transistors, can result. This has a favorable effect on the service life of the converter and, if necessary, smaller and therefore more cost-effective components can be used.

[0053] This method can also be combined with an advance calibration by constant current supply. At the rotational speed n to be determined, the position estimated by the observer is again called up, since at higher rotational speeds the calculation time required for HFI cannot be maintained on the microcontroller that may be used. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Embodiments of the present invention are illustrated by way of example in the schematic drawings. The drawings show:

[0055] Figure 1 A three-dimensional diagram of a household refrigeration appliance.

[0056] Figure 2 Refrigerant circuit with compressor for household refrigeration appliances,

[0057] Figure 3 compressor,

[0058] Figure 4 Electric drives for field-oriented regulation of domestic refrigeration appliances,

[0059] Figure 5 The structure of a field-oriented control device for an electric drive device with field-oriented control,

[0060] Figure 6 High frequency signal,

[0061] Figure 7 control signals for the converter of the electric drive for field-oriented control,

[0062] Figure 8 Duty cycle,

[0063] Fig. 9 The longitudinal current includes high-frequency current components,

[0064] Fig.10 An alternative structure of the field orientation adjustment device, and

[0065] Fig.11 Household laundry drying machine. DETAILED DESCRIPTION

[0066] Figure 1 A household refrigeration appliance 1 is shown in a perspective view as an example of a household appliance, which has a component and a regulated electric drive, which has: a permanently excited three-phase AC synchronous motor; an actuator, which is particularly designed as an inverter for controlling the three-phase AC synchronous motor; and a field-oriented control device for controlling the actuator, wherein the three-phase AC synchronous motor includes a stator and a rotor which is rotatably supported relative to the stator and is part of the component or is provided for driving the component.

[0067] The domestic refrigeration appliance 1 comprises, in particular, a heat-insulating body 10 having an inner container 2 which delimits a coolable interior 3. The coolable interior 3 is provided for storing food, which is not shown in detail.

[0068] In the present exemplary embodiment, the domestic refrigeration appliance 1 has a pivotable door panel 4 for closing the coolable interior space 3. The door panel 4 is pivotably mounted in particular about a vertically extending axis. Figure 1 ), the coolable interior space 3 is accessible.

[0069] In the present embodiment, a plurality of door shelves 5 for storing food are arranged on the side of the door panel 4 that faces the coolable interior space 3. In the coolable interior space 3, a plurality of compartment bottom plates 6 for storing food are arranged, and in the lower region of the coolable interior space 3, a drawer 7 is arranged, in which food can also be stored.

[0070] Household refrigerating appliances 1 included in Figure 2 , for cooling a coolable interior space 3. In the present exemplary embodiment, the refrigerant circuit 20 comprises a refrigerant, which is not shown in detail but is known in principle to a person skilled in the art, a compressor 21, a liquefier 22 connected downstream of the compressor 21, a throttling device 23 connected downstream of the liquefier 22 and which is in particular embodied as a throttling tube or a capillary tube, and an evaporator 24 arranged between the throttling device 23 and the compressor 21. The compressor 21 is preferably arranged inside a machine space of the domestic refrigeration appliance 1, which is in particular located behind the drawer 7.

[0071] The compressor 21 is implemented as a reciprocating piston compressor and Figure 3 Shown in detail.

[0072] The compressor 21 comprises a compressor chamber 31 having an inlet 32 ​​and an outlet 33 for the refrigerant and a piston 34 movably mounted inside the compressor chamber 31. The inlet 32 ​​and the outlet 33 are each provided with a corresponding valve, as is known in principle to a person skilled in the art.

[0073] The compressor 21 includes a crankshaft 35 and a three-phase AC synchronous motor 36. The compressor 21 is one example of the above-mentioned component.

[0074] The three-phase AC synchronous motor 36 is in particular a permanently excited three-phase AC synchronous motor, preferably a brushless DC motor, and comprises a stator 37 and a rotor 38 rotatably supported relative to the stator 37. One end of the crankshaft 35 is coupled to the piston 34 and the other end of the crankshaft 35 is coupled to the rotor 38 of the three-phase AC synchronous motor 36, so that when the domestic refrigeration appliance 1 or the compressor 21 is operated as intended, the piston 34 can reduce the volume 39 enclosed by the compressor chamber 31 and the piston 34 by means of the three-phase AC synchronous motor 36 to compress the coolant.

[0075] In the present exemplary embodiment, the domestic refrigeration appliance 1 comprises an electronic control device 8 which is configured to control the refrigerant circuit 20, in particular the compressor 21 of the refrigerant circuit 20, so that the coolable interior 3 has at least approximately a predetermined or predeterminable setpoint temperature. The electronic control device 8 is preferably configured such that it regulates the temperature of the coolable interior 3. In order to obtain the actual temperature of the coolable interior 3, if necessary, the domestic refrigeration appliance 1 may have at least one temperature sensor, not shown in detail, which is connected to the electronic control device 8.

[0076] In order to control or regulate the refrigerant circuit 20, in the case of the present exemplary embodiment, the domestic refrigeration appliance 1 comprises Figure 4 4 shows an electric drive 40 with field-oriented control, which has a three-phase AC synchronous motor 36 for the compressor 21. If necessary, the three-phase AC synchronous motor 36 is driven at a rated speed n specified by the electronic control unit 8. soll Driven. Rated speed n soll In particular, it is calculated or predefined by the electronic control unit 8 based on the intended cooling of the coolable interior 3 , for example based on the current temperature and a target temperature of the coolable interior 3 .

[0077] In particular, the three-phase AC synchronous motor 36 has a longitudinal inductance L d and the lateral inductance L q In the case of the present embodiment, the longitudinal inductance and the transverse inductance are different. In the case of the present embodiment, the longitudinal inductance L is measured. d and the lateral inductance L q The comprehensive characteristic curve.

[0078] The electric drive 40 includes an actuator for driving the three-phase AC synchronous motor 36. The actuator is implemented as a converter 41 and generates a three-phase supply voltage when the electric drive 40 is in operation. The natural vibration of the three-phase supply voltage has an amplitude and a basic frequency f, which is indirectly dependent on the rated speed n of the three-phase AC synchronous motor 36. soll and actual speed n ist .

[0079] In the present exemplary embodiment, the electric drive 40 with field-oriented control has a measuring device 42, by means of which the line current i of the three-phase synchronous motor 36 is measured. 1,2,3 The actual speed of the three-phase AC synchronous motor 36 is determined without sensors. The measuring device 42 is also configured to calculate the line current i 1,2,3 The transformed transverse current and longitudinal current i q ,i d, as is generally known to those skilled in the art. The quadrature current and longitudinal current i of the three-phase AC motor 36 are q ,i d The mathematical model can calculate the actual speed n of the three-phase AC synchronous motor 36 ist , as is familiar in principle to a person skilled in the art.

[0080] In the present exemplary embodiment, the electric drive 40 with field-oriented control has a field-oriented control device 43 which controls the converter 41 .

[0081] The field-oriented control device 43 forms a cascade structure with an internal current control loop, on which an external speed control loop is superimposed, as is generally known to a person skilled in the art. Figure 5 The structure is partially shown.

[0082] For the field-oriented control device, a control structure is obtained in which the transformed quadrature-axis current and the longitudinal-axis current i are regulated by means of a current control loop. q ,i d In the case of the present embodiment, the current control loop preferably includes a circuit for the transverse current i q The first current regulator 51 and the longitudinal current i d The second current regulator 52. The two current regulators 51, 52 are in particular PI regulators.

[0083] In the present exemplary embodiment, the field-oriented control device 43 or the measuring device 42 is designed such that it measures the line current i of the three-phase AC synchronous motor 36. 1,2,3 The actual longitudinal current value and the actual transverse current value i of the rotor of the three-phase AC synchronous motor 36 are converted into the actual longitudinal current value and the actual transverse current value i of the rotor of the three-phase AC synchronous motor 36. s,d ,i s,q . Transverse current i q Rated value i q,soll The actual value of the transverse current i s,q is the input signal for the first current regulator 51, and the longitudinal current rated value i d,soll The actual value of the longitudinal current i s,d The difference between φ and φ is the input signal for the second current regulator 52 .

[0084] The output signals u of the two current regulators 51, 52 are q ,u d Corresponding to the transformed voltage, the transformed voltage is transformed by means of a transformation 54 which is known in principle to a person skilled in the art into a signal u suitable for actuating the converter 41. w .

[0085] In the present exemplary embodiment, during the starting phase of the compressor 21, the output signal u of the second current regulator 52 is d With high frequency signal u HF Superposition, thus generating a signal u' d , so that during the compressor starting phase, a signal u is provided for controlling the converter 41 w The same is true for the high-frequency signal u HF Therefore, the supply voltage set for the three-phase AC synchronous motor 36 also has a high-frequency voltage component, so the line current i 1,2,3 As well as the actual value of the longitudinal current and the actual value of the transverse current i s,d ,i s,q Has a corresponding high-frequency current component.

[0086] In the present exemplary embodiment, the quadrature-phase current setpoint value i is derived based on this outer speed control loop. q,soll The outer speed control loop has a controller 53 and the outer speed control loop is controlled according to the set speed n soll and actual speed n ist The regulator 53 is in particular a PI regulator.

[0087] In the case of the present embodiment, the longitudinal current rating i d,soll is equal to zero.

[0088] In the present exemplary embodiment, the field-orientation control device 43 is preferably a discrete or digital field-orientation control device 43. The clocking frequency or control frequency of the discrete or digital field-orientation control device 43 and therefore of the two current regulators 51, 52 is, for example, 4 kHz.

[0089] The field-oriented control device 43 requires knowledge of the angular position of the rotor 38 of the three-phase AC synchronous motor 36 relative to the stator 37. The angular position is determined sensorlessly or without a detector.

[0090] During the start-up phase of the field-oriented electric drive 40 , in particular starting from a standstill, the actual longitudinal current value and the actual quadrature-direction current value i s,d ,i s,qThe angular position of the rotor 38 required for the field-oriented control device can be determined based on these high-frequency current components even at relatively low rotational speeds, and the rotational speed of the three-phase AC synchronous motor 36 can therefore be increased during the braking phase until the three-phase AC synchronous motor 36 reaches a predetermined limiting speed of, for example, 1000 revolutions per minute, by operating the regulated electric drive 40 in a speed-controlled manner with the aid of the field-oriented control device 43 and depending on the angular position of the rotor 38 relative to the stator 37, wherein the angular position of the rotor 38 relative to the stator 37 is determined with the aid of the actual longitudinal current value and the actual quadrature-direction current value i s,d ,i s,q The high-frequency current component is used to obtain it.

[0091] In the present embodiment, the signal associated with the high-frequency voltage (high-frequency signal u HF ) is rectangular and has a frequency which is equal to the regulator frequency of the field-orientation regulating device 43, ie 4 kHz in the case of the present exemplary embodiment.

[0092] The start-up phase is followed by an operating phase, during which the supply voltage is not superimposed with high-frequency components. During the operating phase, the electric drive 40 with field-oriented control is operated in a speed-controlled manner by means of a field-oriented control device 43 and as a function of the angular position of the rotor relative to the stator, wherein the angular position of the rotor relative to the stator is determined by means of the actual longitudinal current value and the actual quadrature-direction current value i s,d ,i s,q and mathematical models to obtain it.

[0093] Furthermore, the two current regulators 51 , 52 are operated in particular with a clock cycle which is assigned to a regulator frequency of, in particular, 4 kHz. HF The change curve in Figure 6 and in particular have a voltage of ±10V.

[0094] The pulse width modulated signal for the converter 41 runs, for example, with a clock cycle corresponding to 8 kHz.

[0095] In particular, the output signal u of the second current regulator 52 d The signal associated with the high-frequency voltage (high-frequency signal u HF ). Figure 7 The signal u provided for controlling the converter 41 is shown. w The advantage is that the demodulation is simplified. In the proposed method, it can be formed Very different patterns. The signal associated with the high-frequency voltage (high-frequency signal u HF ) is obtained through experiments.

[0096] If the pattern is converted into a duty cycle, the corresponding Figure 8 The duty cycle length changes. Depending on whether the scheme is superimposed with a positive or negative change at high frequency, the duty cycle is lengthened or shortened by ΔT. The current regulator "sees" nothing from this, because the average value is the same (about 4 kHz).

[0097] In the present exemplary embodiment, the high-frequency current components of the longitudinal current and the transverse current are obtained by measuring the high-frequency signal u HF Discrete measurements are performed at twice the frequency.

[0098] The clock cycles of the respective measurements are set so that in two consecutive measurements, one measurement is performed at the maximum value of the measured current and the other measurement is performed at the minimum value of the measured current. The high-frequency current components of the longitudinal current and the transverse current can then be determined by forming the difference between the respective currents measured in the two consecutive measurements.

[0099] In the present exemplary embodiment, the line current i is measured, in particular, with a clock cycle of 8 kHz. 1,2,3 . Line current i 1,2,3 The actual values ​​i are converted into the actual values ​​of the longitudinal direction of the current and the quadrature direction of the current by means of a transformation known to those skilled in the art. s,d ,i s,q The longitudinal current and the transverse current also have high-frequency current components. Fig. 9 The longitudinal current variation curve is shown.

[0100] The direct-axis current and the quadrature-axis current each have, for example, a high-frequency current component and a DC component. Since the measurement is performed at double the regulator frequency, there are two measurements per regulator clock cycle for the direct-axis current and the quadrature-axis current.

[0101] As already explained, in two measurements carried out one after the other, it is applicable that one measurement is carried out at the maximum value of the measured current (in each case at Fig. 9 ) and another measurement is made at the minimum value of the measured current (at Fig. 9 The high-frequency current components of the longitudinal and transverse currents can then be determined by forming the difference between the respective currents measured in two consecutive measurements. The measurement at T2 is used for current regulation. Based on the combined characteristic curves of the longitudinal and transverse inductances, the angular position of the rotor during the starting phase can be determined.

[0102] In the present exemplary embodiment, it is also provided that at the beginning of the starting phase the converter 41 is actuated in such a way that it moves the piston 34 out of a specific position before the speed-controlled starting.

[0103] Fig.10 An alternative design of the field orientation control device 43 is shown, which is based on the so-called maximum torque current ratio principle. In this principle, the longitudinal current setpoint value i d,soll is not set to zero, but rather to the rated value of the transverse current i q,soll That is determined by the external speed control circuit. The signal generated by the external speed control circuit acts on the output of the regulator 53 and is associated with the torque to be applied by the three-phase AC synchronous motor 36 .

[0104] Additionally, in Fig.10 The structure shown in FIG. 5 has a first functional block 55 and a second functional block 56. The first functional block 55 is located at the output of the regulator 53 of the outer speed control loop and is connected to the quadrature-current setpoint value i q,soll and the actual value of the transverse current i s,q The second functional block 56 is located between the output of the regulator 53 of the external speed control loop and the rated value i of the longitudinal current. d,soll and the actual value of the transverse current i d,q The resulting difference is formed between.

[0105] In addition, the longitudinal current rating i d,soll and the transverse current rating i q,soll In particular, it is determined based on the relationship between the longitudinal inductance and the transverse inductance and based on a signal determined by an external speed control circuit. Since this relationship is nonlinear, the longitudinal current setpoint value i is preferably determined with the aid of a lookup table stored in the functional blocks 55, 56. d,soll and the transverse current rating i q,soll .

[0106] Therefore, the output signal of the first functional block 55 is the actual value of the transverse current i s,q , and the output signal of the second functional block 56 is the actual value of the longitudinal current i s,d .

[0107] The functions of the two functional blocks 55 and 56 are composed of the longitudinal inductance and the transverse inductance L d , L q A comprehensive characteristic curve is obtained and stored, for example, in a look-up table.

[0108] Fig.11 A domestic laundry dryer 101 is shown as a further example of a domestic appliance, which has a corresponding field-oriented controlled electric drive 43, whose three-phase AC synchronous motor is part of a compressor 102 or is provided for driving a compressor 102. The compressor 102 is part of a heat pump circuit 103.

[0109] Reference numerals list

[0110] 1 Household refrigeration appliances

[0111] 2 inner container

[0112] 3 Coolable interior space

[0113] 4 Door panels

[0114] 5-Door Shelf

[0115] 6-grid base

[0116] 7 Drawers

[0117] 8 Electronic control equipment

[0118] 10 body

[0119] 20 Refrigerant circuit

[0120] 21 Compressor

[0121] 22 Liquefier

[0122] 23 Throttling Devices

[0123] 24 Evaporator

[0124] 31 Compressor Room

[0125] 32 Entrance

[0126] 33 Exit

[0127] 34 Piston

[0128] 35 Crankshaft

[0129] 36 Three-phase AC synchronous motor

[0130] 37 Stator

[0131] 38 Rotor

[0132] 39 Volume

[0133] 40 Electric drive

[0134] 41 Converter

[0135] 42 Measuring equipment

[0136] 43 Field directional adjustment device

[0137] 51 First current regulator

[0138] 52 Second current regulator

[0139] 53 Regulator

[0140] 54 Transformation

[0141] 55 First functional block

[0142] 56 Second functional block

[0143] 101 Household laundry dryers

[0144] 102 Compressor

[0145] 103 Heat pump circuit

[0146] i 1,2,3 Line current

[0147] n soll Rated speed

[0148] n ist Actual speed

[0149] i s,d Actual value of longitudinal current

[0150] i s,q Actual value of transverse current

[0151] i d,soll Longitudinal current rating

[0152] i q,soll Transverse current rating

[0153] u q ,u d Output signal

[0154] u w Signal

[0155] u HF High frequency signal

Claims

1. A method for operating a household appliance (1, 101), the household appliance having a component (21, 102) and a regulated electric drive (40), the regulated electric drive having: a permanently excited three-phase AC synchronous motor (36); an actuator for controlling the three-phase AC synchronous motor (36); and a field-oriented control device (43) for controlling the actuator, wherein: The three-phase AC synchronous motor (36) comprises a stator (37) and a rotor (38) which is rotatably mounted relative to the stator (37) and is part of the component (21, 102) or is provided for driving the component (21, 102). The method comprises the following method steps: During a start-up phase of the electric drive (40), - superimposing a supply voltage generated by the actuator and provided for operating the three-phase AC synchronous motor (36) with a high-frequency voltage, whereby the line current of the three-phase AC synchronous motor (36) has a corresponding high-frequency current component, - determining a longitudinal current and a quadrature-axis current assigned to the three-phase AC synchronous motor (36) from the line current, the longitudinal current and the quadrature-axis current having a high-frequency current component corresponding to the high-frequency voltage, - determining the angular position of the rotor (38) relative to the stator (37) based on the high-frequency current components of the longitudinal current and the transverse current, and - increasing the speed of the three-phase AC synchronous motor (36) until the three-phase AC synchronous motor (36) reaches a predetermined limit speed by operating the regulated electric drive (36) in a speed-controlled manner with the aid of the field-oriented control device (43) and as a function of the angular position of the rotor (38) relative to the stator (37), wherein the angular position of the rotor (38) relative to the stator (37) is determined with the aid of high-frequency current components of the longitudinal and quadrature-phase currents, and, during an operating phase following the starting phase, operating the regulated electric drive (40) in a speed-controlled manner by means of the field-oriented control device (43) and as a function of the angular position of the rotor (38) relative to the stator (37), wherein the angular position of the rotor (38) relative to the stator (37) is determined by means of the longitudinal and quadrature-phase currents of the three-phase AC synchronous motor (36) and a mathematical model, The field-oriented control device (43) forms a cascade structure with an internal current control loop, the internal current control loop having a current regulator (51, 52), an external speed control loop being superimposed on the internal current control loop, the method comprising: generating a control signal for the actuator by superimposing a signal generated by the current regulator (52) and associated with the supply voltage and a signal associated with the high-frequency voltage, The field-oriented control device (43) is a discrete field-oriented control device, and the method comprises: the current regulator (52) is operated at a regulator frequency and / or the high-frequency voltage is designed in a rectangular manner, - discretely measuring the longitudinal current and the transverse current at twice the frequency of the high-frequency voltage at least during the starting phase, wherein the measurement is clocked such that, in two measurements carried out one after the other, one measurement is carried out at a maximum value of the measured current and the other measurement is carried out at a minimum value of the measured current; and The high-frequency current components of the direct-axis current and the quadrature-axis current are ascertained by forming a difference between the respective currents measured in two consecutive measurements.

2. The method according to claim 1, comprising: operating the actuator designed as a converter (41) by means of pulse width modulation; And / or the actuator is operated during the operating phase without a superimposed high-frequency voltage.

3. The method according to claim 1 or 2, wherein: The field orientation regulating device (43) is designed according to the maximum torque current ratio principle.

4. The method according to claim 1 or 2, wherein: The component is a compressor (21, 102) comprising a compressor chamber (31) and being arranged for compressing a fluid.

5. The method according to claim 4, wherein: The compressor chamber (31) comprises an inlet (32) and an outlet (33), a piston (34) movably supported inside the compressor chamber (31), and a crankshaft (35), and a rotor (38) of the three-phase AC synchronous motor (36) is coupled to the piston (34) via the crankshaft (35), so that when the compressor (21) is in operation, the piston (34) can reduce a volume (39) enclosed by the compressor chamber (31) and the piston (34) by means of the three-phase AC synchronous motor (36) to compress a fluid, wherein the volume (39) is minimum at a certain position of the piston (34) relative to the compressor chamber (31), and is maximum at another certain position of the piston (34) relative to the compressor chamber (31), the method comprising: controlling the actuator at the beginning of the starting phase so that the actuator moves the piston (34) away from the certain position before starting in a speed-controlled manner.

6. The method according to claim 4, wherein: The household appliance is a household refrigeration appliance (1), comprising: a heat-insulating body (10), which has a coolable inner container (2), which defines a coolable inner space (3) for storing food; a refrigerant circuit (20) configured to cool the coolable inner space (3), which has a coolant as a fluid and the compressor (21); and the regulated electric drive.

7. The method according to claim 4, wherein: The domestic appliance is designed as a domestic laundry dryer (101), which comprises a heat pump circuit (103) and the regulated electric drive (40), the heat pump circuit comprising the compressor (102).

8. The method according to claim 1, wherein: The actuator is designed as a converter (41), and the regulator frequency is equal to the frequency of the high-frequency voltage.

9. A household appliance comprising a component (21, 102) and a regulated electric drive device (40), wherein the regulated electric drive device comprises: a permanently excited three-phase AC synchronous motor (36); an actuator for controlling the three-phase AC synchronous motor (36); and a field-oriented control device (43) for controlling the actuator, wherein: The three-phase AC synchronous motor (36) comprises a stator (37) and a rotor (38) which is rotatably mounted relative to the stator (37), and the three-phase AC synchronous motor is part of the component (21, 102) or is provided for driving the component (21, 102), characterized in that the domestic appliance (1, 101) is configured for carrying out the method according to any one of claims 1 to 8 and is therefore configured for: During a start-up phase of the electric drive (40), - superimposing a supply voltage generated by the actuator and provided for operating the three-phase AC synchronous motor (36) with a high-frequency voltage, whereby the line current of the three-phase AC synchronous motor (36) has a corresponding high-frequency current component, - determining a longitudinal current and a quadrature-axis current assigned to the three-phase AC synchronous motor (36) from the line current, the longitudinal current and the quadrature-axis current having a high-frequency current component corresponding to the high-frequency voltage, - determining the angular position of the rotor (38) relative to the stator (37) based on the high-frequency current components of the longitudinal current and the transverse current, and - increasing the speed of the three-phase AC synchronous motor (36) until the three-phase AC synchronous motor (36) reaches a predetermined limit speed by operating the regulated electric drive (36) in a speed-controlled manner with the aid of the field-oriented control device (43) and as a function of the angular position of the rotor (38) relative to the stator (37), wherein the angular position of the rotor (38) relative to the stator (37) is determined with the aid of high-frequency current components of the longitudinal and quadrature-phase currents, The field-oriented control device (43) forms a cascade structure with an internal current control loop, the internal current control loop has a current regulator (51, 52), an external speed control loop is superimposed on the internal current control loop, and the method comprises: generating a control signal for the actuator by superimposing a signal generated by the current regulator (52) and associated with the supply voltage and a signal associated with the high-frequency voltage, The field-oriented control device (43) is a discrete field-oriented control device, and the method comprises: the current regulator (52) is operated at a regulator frequency and / or the high-frequency voltage is designed in a rectangular manner, - discretely measuring the longitudinal current and the transverse current at twice the frequency of the high-frequency voltage at least during the starting phase, wherein the measurement is clocked such that, in two measurements carried out one after the other, one measurement is carried out at a maximum value of the measured current and the other measurement is carried out at a minimum value of the measured current; and - determining the high-frequency current components of the longitudinal and transverse directions of the current by forming a difference between the respective currents measured in two consecutive measurements, Furthermore, during an operating phase following the starting phase, the regulated electric drive (40) is operated in a speed-regulated manner by means of the field-oriented control device (43) and as a function of the angular position of the rotor (38) relative to the stator (37), wherein the angular position of the rotor (38) relative to the stator (37) is determined by means of the longitudinal current and the transverse current of the three-phase AC synchronous motor (36) and a mathematical model.

10. The household appliance according to claim 9, characterized in that The component is a compressor, which comprises a compressor chamber (31) and is configured to compress a fluid, wherein the compressor chamber (31) comprises an inlet (32) and an outlet (33), a piston (34) movably supported inside the compressor chamber (31), and a crankshaft (35), and a rotor (38) of the three-phase AC synchronous motor (36) is coupled to the piston (34) via the crankshaft (35), so that when the compressor (21) is running, the piston (34) can reduce a volume (39) enclosed by the compressor chamber (31) and the piston (34) by means of the three-phase AC synchronous motor (36) to compress the fluid, wherein the volume (39) is minimum at a certain position of the piston (34) relative to the compressor chamber (31), and the volume (39) is maximum at another certain position of the piston (34) relative to the compressor chamber (31).

11. The household appliance according to claim 10, characterized in that The household appliance is a household refrigeration appliance (1), comprising: a heat-insulating body (10), which has a coolable inner container (2), which defines a coolable inner space (3) for storing food; a refrigerant circuit (20) configured to cool the coolable inner space (3), which has a coolant as a fluid and the compressor (21); and the regulated electric drive.

12. The household appliance according to claim 10, characterized in that The household appliance is a household laundry dryer (101), which comprises a heat pump circuit (103) and the regulated electric drive (40), the heat pump circuit comprising the compressor (102).

13. The household appliance according to claim 9, wherein: The actuator is designed as a converter (41), and the regulator frequency is equal to the frequency of the high-frequency voltage.

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