CONVERTER ELECTRONICS WITH DC MOTOR AND LAUNDRY CARE DEVICE SO THAT

Description

[0001] The present invention relates to a laundry care appliance with a DC motor and inverter electronics, comprising two DC intermediate voltage circuits for rectifying the mains voltage and a voltage regulator. In particular, the invention relates to a mains voltage measurement system in BLDC (brushless DC motor) or PMSM (permanent magnet synchronous motor) inverters.

[0002] Disclosure US 2012 / 098475 A1 discloses a converter.

[0003] Disclosure JP 2014 094165 A discloses a washing machine.

[0004] Disclosure application US 2018 / 226894 A1 discloses a switchable power supply.

[0005] Disclosure KR 2019 0010989 A discloses an air conditioning system.

[0006] Figure 1Figure 1 shows a multi-phase DC motor 100, which can be used in a laundry appliance. On the right side of the image is a schematic cross-section through the motor 130 with permanent magnets 131 (e.g., two-pole) in the center, a three-phase winding 132, and three position sensors (e.g., Hall sensors) 133, which are arranged offset by 120°. On the left side are the control logic 110 and the power stage 120. The control logic 110 evaluates the signals 134 from the position sensors 133 and determines the phase control signals 111 for controlling the motor 140. The power stage 120 converts the mains voltage into the corresponding phase DC voltage signals 121 for controlling the three phases 121 of the motor 130. Inverters or converters are used to convert the mains voltage 123, which is provided, for example, by a power supply 122, into DC voltage.Inverters are used, which include bridge circuits consisting of several diodes to convert the alternating current from the mains into direct current for the motor. For example, a bridge circuit with 4 diodes (B2 circuit) can be used for each phase.

[0007] A monitoring / measuring circuit for the input mains voltage monitors the inverter electronics 110 and 120 for BLDC and PMSM motors, respectively. This circuit provides a control measurement point and signal for use in the inverter. While mains voltage measurement within the inverter is a well-established method, it has the following disadvantages: 1. The mains voltage value is derived from a DC link voltage measurement. This works for motor operation, but not for generator operation, as the DC link voltage increases in this case, thus distorting the mains voltage reading. 2. Direct measurement of the mains voltage before the rectifier bridge, however, leads to further distortion of the mains voltage measurement due to load- and operation-dependent characteristics of the existing PFC choke, as component-specific effects come into play during generator operation. 3.Therefore, in the case of permanent magnet excited multiphase motors (BLDC or PMSM) in generator operation, good DC link voltage stabilization or good control behavior cannot be guaranteed by software solutions, because the control engineering methods require accurate mains voltage measurement to ensure good control behavior and accurate protection functions.

[0008] DC link voltage stabilization to prevent overvoltage and potential damage to the electronics cannot be guaranteed by a falsified mains voltage measurement, as the mains voltage is required for plausibility checks.

[0009] The object underlying the invention is to provide a converter electronics for a drive of a laundry care appliance and a corresponding laundry care appliance which is able to measure the mains voltage as accurately as possible in order to avoid the aforementioned problems of a distorted mains voltage measurement, i.e. overvoltage and possible damage to the electronics, especially in the generator operation of the motor.

[0010] This problem is solved by the items with the features according to the independent claim. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0011] A key aspect of the invention is to perform the mains input voltage measurement not based on the DC link capacitor of the power section (motor side), but rather on the DC link capacitor of the switched-mode power supply (control side), which provides the operating low voltages. If no DC link is provided for a switched-mode power supply (SMP), an independent rectifier bridge with a low load and measuring circuitry can be provided at this rectifier bridge. This avoids the coupling effects of the motor's generator operation in the power section.

[0012] The invention is characterized in that the electronics have the following features: Two independent DC link voltage circuits; one DC link voltage is used for motor control (with appropriate power). A second, low-power DC link voltage is used to provide the operating extra-low voltages via a switched-mode power supply. The mains voltage measurement is generated from the measuring circuit connected to the DC link of the switched-mode power supply. A mains supply circuit with a DC voltage doubler also ensures mains voltages of 120 VAC (DC bridge circuit topology for 120 VAC switched-mode power supplies). To verify proper switching, the switching of this charging circuit is ensured via the voltage measurement difference between measuring points mains voltage measurement (1) and mains voltage measurement (2) (relay contact). The DC link voltage is measured directly. The mains voltage is measured directly via the mains voltage measurement (3) without influence from the motor (for motor and generator operation).The control signal voltages are acquired via analog A / D inputs of the microcontroller or via evaluation electronics.

[0013] This offers the following technical advantages: A direct hardware control signal is no longer required. The DC link voltage can be better stabilized via software. Overvoltage no longer occurs in the electronics, thus preventing damage. Furthermore, the DC link capacitor has a longer lifespan.

[0014] The devices and equipment described below can be of various types. For example, the laundry care appliances described here may be program-controlled household or domestic appliances, washing machines, tumble dryers, combination washer / dryer machines, drying cabinets, etc. The individual control elements described can be implemented by hardware or software components, such as electronic components, and may encompass various technologies, such as semiconductor chips, ASICs, microprocessors, digital signal processors, integrated circuits, electro-optical circuits, and / or passive components.

[0015] The devices and equipment described below may include DC motors, in particular BLDC or PMSM motors. The brushless DC motor (BLDC motor) is constructed like a three-phase synchronous machine with permanent magnet excitation. The often three-phase winding is controlled by a suitable circuit to generate a rotating magnetic field that drives the permanent magnet rotor. The control behavior is largely similar to that of a DC shunt-wound motor. In BLDC motors, the rotor is equipped with permanent magnets, and the stationary stator contains the coils. In addition to the internal rotor design, the external rotor design is also frequently used. The winding is typically designed as a three-phase system and, depending on the speed range, with a low to very high number of poles.The PMSM motor is a single-phase or three-phase synchronous machine in which a constantly magnetized rotor is driven synchronously by a rotating magnetic field in the stator. The rotating synchronous motor's motion is synchronous with the alternating current. Therefore, the rotational speed is linked to the frequency of the alternating current via the number of pole pairs. The field in the rotor is generated by permanent magnets. Particularly in large synchronous machines, the stator coils are sometimes driven by a frequency converter with a suitable, controlled alternating current. This enables the implementation of high-power, variable-speed drives.

[0016] According to a first aspect, the problem according to the invention is solved by a laundry care appliance with a DC motor and inverter electronics, wherein the inverter electronics comprise: a mains supply circuit for supplying the laundry care appliance with a mains voltage; a first DC intermediate voltage circuit configured to rectify the mains voltage into a first intermediate circuit voltage for supplying a power stage for phase control of the DC motor; a second DC intermediate voltage circuit configured to rectify the mains voltage into a second intermediate circuit voltage for supplying a switched-mode power supply for providing operating voltages for a control logic for controlling the power stage;and a voltage regulator configured to control the first DC intermediate voltage circuit based on a measured value of the mains voltage and to determine the measured value of the mains voltage based on the second DC intermediate voltage circuit.

[0017] This achieves the technical advantage of better stabilizing the first intermediate circuit voltage for supplying a power stage, thus preventing overvoltage in the electronics and preventing damage to the electronics. Furthermore, it results in a longer service life for the first intermediate voltage circuit.

[0018] In an advantageous embodiment of the laundry care device, the DC motor is a permanent magnet excited multiphase motor, in particular a permanent magnet excited synchronous motor, PMSM, or a brushless DC motor, BLDC, and the converter electronics comprise inverter electronics for the permanent magnet excited multiphase motor.

[0019] This achieves the technical advantage that the inverter electronics can easily stabilize these common DC motors, so that they run stably in motor and generator modes without dangerous overvoltages.

[0020] In an advantageous embodiment of the laundry care device, the voltage regulator is designed to determine the measured value of the mains voltage in both motor operation and generator operation of the DC motor.

[0021] This achieves the technical advantage that the voltage regulator ensures stable motor behavior in both motor and generator modes.

[0022] According to the invention, the second DC intermediate voltage circuit comprises an intermediate circuit capacitor for smoothing the second intermediate circuit voltage.

[0023] This achieves the technical advantage that the second intermediate circuit voltage can be determined more accurately due to the smoothing and does not exhibit strong fluctuations.

[0024] In an advantageous embodiment of the laundry care device, the voltage regulator is configured to control the first DC intermediate voltage circuit based on a voltage drop across the intermediate circuit capacitor of the second DC intermediate voltage circuit.

[0025] This results in the technical advantage that a more accurate measurement of the mains voltage is formed at the intermediate circuit capacitor of the second DC intermediate voltage circuit, which is also subject to less fluctuation than at the intermediate circuit capacitor of the first DC intermediate voltage circuit.

[0026] In an advantageous embodiment of the laundry care device, the converter electronics comprise a resistance divider configured to determine a voltage drop across the intermediate circuit capacitor of the second DC intermediate voltage circuit.

[0027] This achieves the technical advantage that a measurement of the mains voltage can be easily determined using this high-impedance resistor divider.

[0028] In an advantageous embodiment of the laundry care device, the second DC intermediate voltage circuit is electrically decoupled from the first DC intermediate voltage circuit.

[0029] This achieves the technical advantage that irregularities in the first, i.e., motor-side, DC intermediate voltage circuit do not affect the second DC intermediate voltage circuit on the side of the switched-mode power supply, and therefore the mains voltage can be determined very accurately without disturbing influences from motor operation.

[0030] In an advantageous embodiment of the laundry care device, the inverter electronics comprise a first charging circuit for charging a first phase of the DC motor, the inverter electronics have a relay for controlling a switching of the first charging circuit; and the inverter electronics are configured to monitor the switching of the first charging circuit based on a voltage difference at the relay.

[0031] This achieves the technical advantage that the switching of the motor's phase currents from the first charging circuit to the second and third charging circuits can be carried out precisely, since the mains voltage can be measured accurately via the voltage difference at the relay.

[0032] In an advantageous embodiment of the laundry care device, the inverter electronics comprise a microcontroller configured to determine and evaluate the voltage difference at the relay.

[0033] This achieves the technical advantage that the microcontroller can very effectively evaluate the measured mains voltage, which is previously converted into a digital value via an A / D converter, in order to ensure phase-accurate current supply to the motor.

[0034] In an advantageous embodiment of the laundry care device, a first contact of the relay is coupled to the mains supply circuit via a PFC choke; and a second contact of the relay is coupled to the first DC intermediate voltage circuit.

[0035] This achieves the technical advantage that the measured value of the mains voltage takes into account the voltage drop at the PFC choke, and this can be compensated for in the voltage regulator.

[0036] In an advantageous embodiment of the laundry care device, the inverter electronics comprise a first measuring circuit for measuring the mains voltage at the first contact of the relay and a second measuring circuit for measuring the mains voltage at the second contact of the relay; and the inverter electronics are configured to monitor the switching of the first charging circuit based on a difference between the mains voltages measured by both measuring circuits.

[0037] This achieves the technical advantage that two measurements increase the accuracy of the mains voltage measurement.

[0038] In an advantageous embodiment of the laundry care device, the inverter electronics comprise a third measuring circuit for measuring the mains voltage at the second DC intermediate voltage circuit; and the inverter electronics are configured to further monitor the switching of the first charging circuit based on the mains voltage measured with the third measuring circuit.

[0039] This results in the technical advantage that a higher accuracy can be achieved with the third measuring circuit for mains voltage measurement on the second DC intermediate voltage circuit than with the first and second measuring circuits on the motor-side first DC intermediate voltage circuit.

[0040] In an advantageous embodiment of the laundry care device, the inverter electronics comprise a fourth measuring circuit for measuring the mains voltage at the first DC intermediate voltage circuit; and the inverter electronics are configured to stabilize the mains voltage measured with the fourth measuring circuit based on the mains voltage measured with the third measuring circuit.

[0041] This achieves the technical advantage that the mains voltage measured with the third measuring circuit is very accurate compared to the other measuring circuits and is therefore particularly suitable for stabilizing or regulating the mains voltages measured with the other measuring circuits.

[0042] In an advantageous embodiment of the laundry care device, the four measuring circuits each comprise a resistance divider for determining a respective measured value of the mains voltage.

[0043] This achieves the technical advantage that the respective measured value of the mains voltage can be easily determined using these high-impedance resistor dividers.

[0044] According to a second aspect, the object of the invention is achieved by an inverter electronics for a laundry care appliance with a DC motor, wherein the inverter electronics comprise: a mains supply circuit for supplying the laundry care appliance with a mains voltage; a first DC intermediate voltage circuit configured to rectify the mains voltage into a first intermediate circuit voltage for supplying a power stage for phase control of the DC motor; a second DC intermediate voltage circuit configured to rectify the mains voltage into a second intermediate circuit voltage for supplying a switched-mode power supply for providing operating voltages for a control logic for controlling the power stage;and a voltage regulator configured to control the first DC intermediate voltage circuit based on a measured value of the mains voltage and to determine the measured value of the mains voltage based on the second DC intermediate voltage circuit.

[0045] This achieves the technical advantage of better stabilizing the first intermediate circuit voltage for supplying a power stage, thus preventing overvoltage in the electronics and preventing damage to the electronics. Furthermore, it results in a longer service life for the first intermediate voltage circuit.

[0046] According to a third aspect, the problem according to the invention is solved by a method for operating a laundry care appliance with a DC motor and inverter electronics, wherein the method comprises the following steps: supplying the laundry care appliance with a mains voltage by means of a mains supply circuit; rectifying the mains voltage into a first intermediate circuit voltage for supplying a power stage for phase control of the DC motor, by means of a first DC intermediate voltage circuit; rectifying the mains voltage into a second intermediate circuit voltage for supplying a switched-mode power supply for providing operating voltages for a control logic for driving the power stage, by means of a first DC intermediate voltage circuit; regulating the first DC intermediate voltage circuit based on a measured value of the mains voltage, by means of a voltage regulator;and determining the measured value of the mains voltage based on the second DC intermediate voltage circuit, by the voltage regulator.

[0047] This achieves the technical advantage that the method can be used in inverter electronics for a laundry appliance with a DC motor. Furthermore, the first intermediate circuit voltage for supplying a power stage can be better stabilized, preventing overvoltage in the electronics and thus avoiding damage to the electronics. Additionally, operating such a method results in a longer service life for the first intermediate voltage circuit.

[0048] Exemplary embodiments of the invention are shown in the drawings and are described in more detail below.

[0049] They show: Fig. 1 a schematic representation of a 3-phase electric motor 100 with associated circuitry; Fig. 2 a circuit diagram of an inverter electronics 200 of a permanent magnet multi-phase electric motor with mains voltage measurement at the DC intermediate voltage circuit of the power section according to an exemplary embodiment; Fig. 3 a circuit diagram of an inverter electronics 300 of a permanent magnet multi-phase electric motor with mains voltage measurement at the DC intermediate voltage circuit of the switched-mode power supply according to an exemplary embodiment; Fig. 4 a block diagram of an inverter electronics 400 of a permanent magnet multi-phase electric motor with various measuring points for measuring the mains voltage according to an exemplary embodiment; Fig. 5 a circuit diagram of a mains supply circuit 410 in the inverter electronics 400 Fig. 4according to an exemplary embodiment; Fig. 6 shows a circuit diagram of a third charging circuit 423 in the inverter electronics 400. Fig. 4 according to an exemplary embodiment; Fig. 7 a circuit diagram of a second charging circuit 422 in the inverter electronics 400 from Fig. 4 according to an exemplary embodiment; Fig. 8 a circuit diagram of a PFC choke 450 in the inverter electronics 400 from Fig. 4 according to an exemplary embodiment; Fig. 9 a circuit diagram of a second intermediate circuit 432 in the converter electronics 400 from Fig. 4 according to an exemplary embodiment; Fig. 10 a circuit diagram of a switched-mode power supply 470 in the inverter electronics 400 made of Fig. 4 according to an exemplary embodiment; Fig. 11 a circuit diagram of a first intermediate circuit 431 in the converter electronics 400 from Fig. 4according to an exemplary embodiment; Fig. 12 a circuit diagram of a first charging circuit 421 in the inverter electronics 400 from Fig. 4 according to an exemplary embodiment; Fig. 13 a circuit diagram of a measuring circuit 441, 442, 443, 444 for measuring the mains voltage at different measuring points in the converter electronics 400 from Fig. 4 according to an exemplary embodiment; Fig. 14 a) - d) four diagrams showing the distortion of the mains voltage measurement as a function of the motor load when using known measuring circuits for mains voltage measurement; Fig. 15 a), b) two diagrams illustrating the differences between a mains voltage measurement at the DC intermediate circuit of the power section with known measuring circuits and a mains voltage measurement at the DC intermediate circuit of the switched-mode power supply according to embodiments of the invention; and Fig. 16 a schematic representation of a laundry care appliance 1600 with an electric motor 100, as above. Figure 1described, according to an exemplary embodiment.

[0050] Fig. 1Figure 1 shows a schematic representation of a 3-phase electric motor 100 with its associated circuitry. As already described in the introduction, the right side of the image shows a schematic cross-section through the motor 130 with permanent magnets 131 (e.g., two-pole) in the center, a three-phase winding 132, and three position sensors (e.g., Hall sensors) 133, which are arranged at 120° intervals. The control logic 110 and the power stage 120 are shown on the left side. The control logic 110 evaluates the signals 134 from the position sensors 133 and determines the phase control signals 111 for controlling the motor 140. The power stage 120 converts the mains voltage into the corresponding phase DC voltage signals 121 for controlling the three phases 121 of the motor 130. Inverters or converters are used to convert the mains voltage 123, which is provided, for example, by a power supply 122, into DC voltage.Inverters are used, which include bridge circuits consisting of several diodes to convert the alternating current from the mains into direct current for the motor. For example, a bridge circuit with four diodes (B2 circuit) can be used for each phase. Examples of such converter or inverter circuits are described in more detail below.

[0051] Fig. 2 shows a circuit diagram of an inverter electronics 200 of a permanent magnet excited multiphase electric motor with mains voltage measurement at the DC intermediate voltage circuit of the power section according to an exemplary embodiment.

[0052] The inverter electronics 200 comprise a mains supply circuit 210, a PFC choke 211, a rectifier bridge 230 with smoothing capacitor 231, and a resistor divider for measuring the mains voltage. The mains supply circuit 210 includes three conductors: an L1 conductor (or first phase of the live conductor), an N1 conductor (or neutral conductor to the first phase), and a PE conductor to ground. The L1 conductor is connected to output L1.2 via a coil L2. The N1 conductor is connected to output N1.2 via a coil L1. The PE conductor is connected to output L1.2 via a capacitor C2 and to output N1.2 via a capacitor C3. The PFC choke is connected to output L1.2, and the rectifier bridge 230, in the form of a B2 circuit, is connected between the output of the PFC choke and output N1.2. The resistor divider 220 for measuring the mains voltage is also connected at these two points.The resistor divider comprises a series circuit with resistors R1, R5, R2, and R3, with a tap between R2 and R3. A measurement of the mains voltage 221 can be determined via R4 from this tap. This measurement is then fed to a microcontroller ADC to ensure appropriate control of the inverters.

[0053] The mains voltage value is derived here based on the DC link voltage measurement. While this usually works for the motor's operation as a motor, it does not work for the motor's operation as a generator, since the DC link voltage increases in this case and thus distorts the mains voltage value 221. A direct measurement of the mains voltage before the rectifier bridge 230, in turn, leads to the mains voltage measurement 221 also being distorted by the load- and operation-dependent characteristics of the PFC choke 211, as component-specific effects come into play during generator operation.

[0054] The mains voltage measurement 221 is distorted during regenerative operation of the motor (e.g., motor braking). The intermediate circuit voltage at capacitor 231 is higher than the mains voltage, and the voltage drop across the PFC choke 211 becomes almost zero, thus distorting the measured value of the mains voltage 221 in measuring branch 220 by the voltage drop UL across the PFC choke 211.

[0055] Therefore, in generator operation, good DC link voltage stabilization or good control behavior cannot be guaranteed by software solutions, because the control engineering methods require accurate mains voltage measurement to ensure good control behavior and accurate protection functions.

[0056] DC link voltage stabilization to prevent overvoltage and potential damage to the electronics cannot be guaranteed by a falsified mains voltage measurement, as the mains voltage is required for plausibility checks.

[0057] For these reasons, the mains input voltage measurement is not carried out based on the DC link capacitor 231 of the power section (motor side), as in Figure 2 depicted, but based on the intermediate circuit capacitor 321 of the switching power supply 310 (control side), which provides the operating extra-low voltages, as shown in Figure 3 As shown. If no intermediate circuit is provided, an independent rectifier bridge with a small load and measuring circuitry can be provided at this rectifier bridge. This avoids the coupling effects of the motor's generator operation in the power section.

[0058] Fig. 3shows a circuit diagram of an inverter electronics 300 of a permanent magnet excited multi-phase electric motor with mains voltage measurement at the DC intermediate voltage circuit of the switched-mode power supply according to an exemplary embodiment.

[0059] The converter electronics 300 comprise a rectifier bridge 330 in the form of a B2 circuit with a smoothing capacitor 331 and a resistor divider 320 for measuring the mains voltage 321, as well as a switching power supply 310 that can generate low voltages of, for example, 15 Vdc, 9 Vdc, 5 Vdc and 3.3 Vdc. The rectifier bridge 330 is connected to the two terminals mentioned above. Figure 2The outputs L1.2 and N1.2 described above are connected. The resistor divider 320 and the switching power supply 310 are connected between an upper tap 332 and a lower tap 333 of the rectifier bridge 330. The resistor divider comprises a series circuit with resistors R1.1, R5.1, R2.1, and R3.1, with a tap between R2.1 and R3.1. A measured value of the mains voltage 321 can be determined via R4.1 from this tap. The measured value 321 is fed to a microcontroller ADC to ensure appropriate control of the inverters.

[0060] The mains input voltage measurement 321 is not performed here on the basis of the intermediate circuit capacitor 231 of the power section (motor side), as described above. Figure 2The measurement is based not on the DC link capacitor 331 of the switching power supply 310 (control side), which provides the operating low voltages. This means the mains voltage is measured across the DC link voltage of the switching power supply. Since this is fully decoupled from the motor control circuit, the correct mains voltage is measured here at twice the mains frequency. Therefore, the control system can correctly regulate the motor DC link voltage.

[0061] If no intermediate circuit is provided, an independent rectifier bridge with a small load and measuring circuitry can be installed on this rectifier bridge. This avoids the coupling effects of the motor's generator operation in the power section.

[0062] Fig. 4Figure 400 shows a block diagram of an inverter electronics unit of a permanent magnet excited multiphase electric motor with various measuring points for measuring the mains voltage according to an exemplary embodiment.

[0063] The inverter electronics 400 have two independent DC link voltage circuits 431 and 432. One DC link voltage, generated in the first DC link voltage circuit, is used for motor control (with corresponding power). A second, lower-power DC link voltage, generated in the second DC link voltage circuit 432, is used to provide the operating low voltages via a switched-mode power supply 470. The mains voltage measurement is generated from the measuring circuit 443, which is connected to the DC link 432 of the switched-mode power supply 470. The inverter electronics 400 have a mains supply circuit 410 with a DC voltage doubler, which also ensures mains voltages of 120 VAC (DC bridge circuit topology for 120 VAC switched-mode power supplies).To ensure proper switching, the switching of this charging circuit is verified by the voltage difference between measuring point mains voltage measurement (1) 441 and mains voltage measurement (2) 442 (relay contact). The intermediate circuit voltage is measured directly. The mains voltage is measured directly via mains voltage measurement (3) 443 without influence from the motor 480 (for motor and generator operation). The control signal voltages are acquired via analog A / D inputs of the microcontroller or via evaluation electronics.

[0064] That is, the inverter electronics 400 includes a mains supply circuit 410, e.g. according to the one above. Figure 2 The described mains supply circuit 210. The inverter electronics 400 comprise a PFC choke 450 with a downstream resistor 460. The PFC choke can be, for example, the one described above. Figure 2The described PFC choke 211 corresponds to the inverter electronics 400, which includes a first DC intermediate voltage circuit 431 (abbreviated first intermediate circuit), e.g., corresponding to the one described above. Figure 2 The intermediate voltage circuit 230, 231 described above. The converter electronics 400 includes a second DC intermediate voltage circuit 432 (abbreviated second intermediate circuit), e.g. corresponding to the one described above. Figure 3 The intermediate voltage circuit 330, 331 described. The converter electronics 400 comprises three charging circuits 421, 422, 423 for charging the three phases of the electric motor with current of the corresponding phase, e.g., according to the phase currents 121, as in Figure 1 described. The inverter electronics 400 also include a switched-mode power supply 470, e.g., corresponding to the one described above. Figure 3described switching power supply 310. The inverter electronics 400 further comprise four measuring circuits 441, 442, 443, 444 for measuring the mains voltage at various points of the circuit, a first DC intermediate voltage circuit 431, e.g., corresponding to the one described above. Figure 2 described intermediate voltage circuit 230, 231.

[0065] The third charging circuit 423 is coupled to the mains supply circuit 410, e.g. as shown in the following illustrations. Figures 5 to 13 The second intermediate circuit 432 is coupled between the mains supply circuit 410 and the switching power supply 470, e.g. as shown in the following. Figures 5 to 13 The second charging circuit 422 is connected between the mains supply circuit 410 and the PFC choke 450, e.g. as shown in the following. Figures 5 to 13 The first intermediate circuit 432 is connected between the resistor 460 and the motor 480, e.g. as shown in the following. Figures 5 to 13The first charging circuit 421 is connected to the PFC choke 450 and the resistor 460, e.g. as shown in the following. Figures 5 to 13 .

[0066] A first measuring circuit 441 measures the mains voltage between PFC choke 450 and resistor 460. A second measuring circuit 442 measures the mains voltage between resistor 460 and the first intermediate circuit 431. A third measuring circuit 443 measures the mains voltage between the second intermediate circuit 432 and the switching power supply 470, as described above. Figure 3 described. A fourth measuring circuit 444 measures the mains voltage at the first intermediate circuit 431, as e.g. above. Figure 2 described.

[0067] The inverter electronics 400 can be used in a laundry care appliance, e.g. a laundry care appliance 1600 as shown below. Figure 16 described. Such a laundry care appliance 1600 comprises a DC motor 480, e.g. a DC motor 100 with wiring as described. Figure 1 described with inverter electronics 400.

[0068] The inverter electronics 400 comprise the following circuits: a mains supply circuit 410 for supplying the laundry appliance with a mains voltage, e.g., a mains supply circuit 410 as described below. Figure 2 described; a first DC intermediate voltage circuit 431, which is configured to convert the mains voltage into a first intermediate circuit voltage for supplying a power stage (e.g., a power stage 120 as described) Figure 1 (described) for phase control of the DC motor 480, 130 to rectify; a second DC intermediate voltage circuit 432, which is configured to convert the mains voltage into a second intermediate circuit voltage for supplying a switched-mode power supply 470 (e.g., a switched-mode power supply 310 as described above) Figure 3(described) to provide operating voltages for a control logic 110 to control the power stage 120. The converter electronics 400 has a voltage regulator, e.g. in the form of a microcontroller 490, which is configured to control the first DC intermediate voltage circuit 431 based on a measured value of the mains voltage 443 and to determine the measured value of the mains voltage 443 based on the second DC intermediate voltage circuit 432.

[0069] In particular, the DC motor 480 can be a permanent magnet multiphase motor, such as a permanent magnet synchronous motor (PMSM) or a brushless DC motor (BLDC). The inverter electronics 400 can include inverter electronics for the permanent magnet multiphase motor.

[0070] The voltage regulator or microcontroller 490 is designed to determine the measured value of the mains voltage 443 in both motor operation and generator operation of the DC motor 480. In particular, during generator operation of the motor, the measured value of the mains voltage 443 at the second DC intermediate voltage circuit 432 allows for better stabilization of the intermediate circuit voltage (at the first DC intermediate voltage circuit 431).

[0071] The second DC intermediate voltage circuit 432 includes an intermediate circuit capacitor 331, e.g. as in Figure 3 As shown, it includes a capacitor for smoothing the second intermediate circuit voltage. Such an intermediate circuit capacitor, C1105, is also used in... Figure 9 A more detailed explanation.

[0072] The voltage regulator or microcontroller 490 is designed to control the first DC intermediate voltage circuit 431 based on a voltage drop across the intermediate circuit capacitor 331 of the second DC intermediate voltage circuit 432, as e.g. in Figure 3 The voltage drop can be measured, for example, with the third measuring circuit, and the measured value can be digitized via an A / D converter and made available to the 490 microcontroller.

[0073] The inverter electronics 400 include a resistance divider, e.g. a resistance divider 320 as in Figure 3 shown, which is designed to determine a voltage drop across the intermediate circuit capacitor 331 of the second DC intermediate voltage circuit 432.

[0074] The second DC intermediate voltage circuit 432 is electrically decoupled from the first DC intermediate voltage circuit 431.

[0075] In one embodiment, the inverter electronics 400 comprises a first charging circuit 421 for charging a first phase of the DC motor 480. The inverter electronics 400 has a relay, e.g., the one described in Figure 12 The illustrated relay K103 controls the switching of the first charging circuit 421. The inverter electronics 400 are configured to monitor the switching of the first charging circuit 421 based on a voltage difference across relay K103. Furthermore, the inverter electronics 400 include a second 422 and a third 423 charging circuit for charging a second and third phase of the DC motor 480. Corresponding relays are used to control the switching of the second and third charging circuits, as shown in the Figure 6 and 7The inverter electronics 400 are designed to monitor the switching of the second and third charging circuits 422, 423 based on a voltage difference at the corresponding relays K101 and K102 of the second and third charging circuits 422, 423.

[0076] As already mentioned, the inverter electronics 400 includes a microcontroller 490, which is designed to determine and evaluate the voltage difference at relay K103 (and at the two other relays K101 and K102).

[0077] The first contact 1201 of relay K103 is coupled to the mains supply circuit 410 via a PFC choke 450. A second contact 1202 of relay K103 is coupled to the first DC intermediate voltage circuit 431.

[0078] The inverter electronics 400 comprise a first measuring circuit 441 for measuring the mains voltage at the first contact 1201 of relay K103 and a second measuring circuit 442 for measuring the mains voltage at the second contact 1202 of relay K103. The inverter electronics 400 are configured to monitor the switching of the first charging circuit 421 based on a difference between the mains voltages measured by both measuring circuits 441 and 442.

[0079] The inverter electronics 400 include a third measuring circuit 443 for measuring the mains voltage at the second DC intermediate voltage circuit 432. The inverter electronics 400 is configured to monitor the switching of the first charging circuit 421 further based on the mains voltage measured with the third measuring circuit 443, i.e., the mains voltage measured at the switching power supply.

[0080] The inverter electronics 400 can include a fourth measuring circuit 444 for measuring the mains voltage at the first DC intermediate voltage circuit 431. The inverter electronics 400 are configured to stabilize the mains voltage measured by the fourth measuring circuit 444 based on the mains voltage measured by the third measuring circuit 443. The stabilization or regulation of the mains voltage can be performed in the microcontroller 490.

[0081] In one embodiment, the four measuring circuits 441, 442, 443, 444 each comprise a resistance divider, e.g. a resistance divider 220, 320 as in the Figures 2 and 3 shown, for determining a respective measured value of the mains voltage. Figure 13 shows a possible circuit implementation of such a measuring circuit.

[0082] Exemplary circuit implementations of the in Figure 4 The circuits shown are described in the following Figures 5 to 13 explained in more detail.

[0083] Fig. 5 shows a circuit diagram of a mains supply circuit 410 in the converter electronics 400. Fig. 4 according to an exemplary embodiment.

[0084] The mains supply circuit 410 comprises three conductors: a live conductor (L0), a neutral conductor (NO), and a protective earth (PE) conductor. The live conductor (L0) is routed through the first coil of a transformer. The neutral conductor (NO) is routed through the second coil of the transformer. The protective earth (PE) conductor is tapped between a first capacitor (C100) and a second capacitor (C102) in a series connection of these two capacitors, which are connected to the output of the transformer.

[0085] Fig. 6 shows a circuit diagram of a third charging circuit 423 in the inverter electronics 400. Fig. 4 according to an exemplary embodiment.

[0086] The third charging circuit 423 includes a relay K102, which is connected to the NO conductor of the in Figure 5 The depicted mains supply circuit 410 is switched, and a transistor T101, e.g. a bipolar transistor, is used to switch the third phase current to the motor. The relay K102 can, for example, be implemented as a monostable multivibrator.

[0087] Fig. 7 shows a circuit diagram of a second charging circuit 422 in the inverter electronics 400. Fig. 4 according to an exemplary embodiment.

[0088] The second charging circuit 422 includes a relay K101, which is connected to the L0 conductor of the in Figure 5The circuit shown is a mains supply circuit 410, and a transistor T100, e.g., a bipolar transistor, for switching the second phase current to the motor. The relay K101 can, for example, be implemented as a monostable multivibrator. Another transistor T102, e.g., a field-effect transistor, is implemented in the switching path, which controls the switching on and off of transistor T100.

[0089] Fig. 8 shows a circuit diagram of a PFC choke 450 in the inverter electronics 400. Fig. 4 according to an exemplary embodiment.

[0090] The input of the PFC (Power Factor Correction) choke is connected to circuit 422 described above. The output of the PFC choke is connected to circuits 421, 460, and 441 described above.

[0091] Chokes like the PFC choke 450 are coils or inductors used to limit currents in electrical lines, to temporarily store energy in the form of their magnetic field, for impedance matching, or for filtering. The PFC choke 450 is connected in series with the other components of the inverter electronics 400. The PFC choke 450 operates in series with the supply voltage in the switched-mode power supply to reduce the harmonic distortion of the supply network.

[0092] Fig. 9 shows a circuit diagram of a second intermediate circuit 432 in the converter electronics 400. Fig. 4According to an exemplary embodiment. The second intermediate circuit 432, or second DC intermediate voltage circuit, comprises a rectifier D103, implemented as a B2 circuit with four diodes, and a smoothing capacitor C1105, connected to the two contacts 1 and 3 of the bridge circuit D103. The second intermediate circuit 432 is connected to the power supply 410 on the input side (via a resistor R104) and provides the operating low voltages for the switching power supply 470 on the output side. The second intermediate circuit 432 can be configured according to circuit 300 in Figure 3 to be realized.

[0093] Fig. 10 shows a circuit diagram of a switched-mode power supply 470 in the inverter electronics 400. Fig. 4 according to an exemplary embodiment.

[0094] A switched-mode power supply (SMS) is an electronic component that converts an unregulated input voltage into a constant output voltage. The following processes take place within the SMS: rectification of the AC mains voltage, smoothing of the resulting DC voltage, chopping of the DC voltage, transformation of the resulting AC voltage, rectification of the AC voltage, and filtering of the DC voltage. A control circuit ensures that the amount of energy supplied to the power supply is precisely the amount that needs to be delivered to the load. This control is achieved through pulse duration or pulse phase control.

[0095] The 470 switching power supply features a TR100 ferrite core transformer to achieve voltage transformation and galvanic isolation between the output and input sides. To also galvanically isolate the control loop from the mains, the 470 switching power supply incorporates a V110 optocoupler to transmit the switching signals to the power transistors. Figure 10 The separation is achieved by a transformer TR100 and an optocoupler V110 in the control circuit.

[0096] Fig. 11 shows a circuit diagram of a first intermediate circuit 431 in the converter electronics 400. Fig. 4 according to an exemplary embodiment.

[0097] The first intermediate circuit 431, or first DC intermediate voltage circuit, comprises a rectifier D302, implemented as a B2 circuit with four diodes, and a smoothing capacitor C1104, connected to the two contacts 1 and 4 of the bridge circuit D302. The first intermediate circuit 431 is connected on its input side via a resistor R130 to circuits 421 and 441, and directly, i.e., without resistor R130, to circuits 421 and 442. On its output side, the first intermediate circuit 431 is connected to the protective earth (PE) via a center tap on a series connection of two capacitors C114 and C115. The first intermediate circuit 431 provides the operating voltages for the motor phases on its output side. The first intermediate circuit 431 can be configured, for example, according to circuit 200 in [reference missing]. Figure 2 to be realized.

[0098] Fig. 12 shows a circuit diagram of a first charging circuit 421 in the inverter electronics 400. Fig. 4according to an exemplary embodiment.

[0099] The first charging circuit 421 comprises a relay K103 with a first contact 1201, which is connected to the circuits 450, 441, and 460 described above, and a second contact 1202, which is connected to the circuits 460, 442, and 431 described above. The output of relay K103 is connected to a diode D117. The first charging circuit 421 also includes a transistor T114, e.g., a bipolar transistor, for switching the first phase current to the motor. Relay K103 can, for example, be implemented as a monostable multivibrator.

[0100] Fig. 13 shows a circuit diagram of a measuring circuit 441, 442, 443, 444 for measuring the mains voltage at different measuring points in the converter electronics 400. Fig. 4 according to an exemplary embodiment.

[0101] The measuring circuit comprises a resistor divider consisting of resistors R192, R193, R194, and R196 connected in series, and a tap between R194 and R196 from which a potential of 3.3V flows to ground via resistor R195. The tap is protected against reverse polarity by a diode D190. A capacitor C191 is connected in parallel to resistor R195 and to ground. A second capacitor, C192, is connected to ground at the measuring output Meas_LI.

[0102] Fig. 14 a)-d) Four diagrams show the distortion of the mains voltage measurement depending on the motor load when using known measuring circuits for mains voltage measurement.

[0103] Figure 14a ) shows the motor speed of an electric motor 100, e.g. according to Figure 1 , in which the mains voltage is not measured at the DC intermediate voltage circuit of the switching power supply, but the mains voltage is measured at the DC intermediate voltage circuit of the power section.

[0104] After a certain time, 1401, of approximately 33:38 minutes, the engine shuts down. Figure 14a The shutdown command is shown in Figure 1. While previously a speed of approximately 1400 revolutions per minute was instructed, the speed is abruptly reduced to zero at time 1401. Figure 14b ) shows the actual engine speed. This increases to 1400 revolutions per minute up to time 1401 and then slowly drops to zero. Figure 14c Figure 1 shows the measured DC link voltage at the motor-side DC link circuit. It fluctuates considerably between 275 V and 375 V. After the shutdown command at time 1401, it even rises to 375 V and only drops again slightly after a long time, at approximately 34:25 minutes. Figure 14dFigure 1 shows the measured mains voltage at the motor-side intermediate voltage circuit. The measured mains voltage also fluctuates considerably between 320V and 345V. After the shutdown command at time 1401, it fluctuates between 325V and 330V.

[0105] Fig. 15 a),b) Two diagrams illustrate the differences between a mains voltage measurement at the DC intermediate circuit of the power section using known measuring circuits and a mains voltage measurement at the DC intermediate circuit of the switched-mode power supply according to embodiments of the invention.

[0106] Curve 1502 shows the mains voltage measurement at the motor-side DC intermediate voltage circuit, e.g. according to Figure 2 , while curve 1501 measures the mains voltage at the SNT-side DC intermediate voltage circuit, e.g. according to Figure 3 represents. Figure 15b ) represents an enlarged section of Figure 15a) while curve 1502 fluctuates strongly and especially after the engine is switched off, corresponding to 1401. Figure 14a While ) assumes a high voltage value of approximately 345V, curve 1501 does not experience any fluctuations; it remains constant at a voltage value of approximately 325V.

[0107] Fig. 16 shows a schematic representation of a laundry care appliance 1600 with an electric motor 100, as above. Figure 1 described, according to an exemplary embodiment.

[0108] A laundry care appliance (1600) is understood to be a device used for laundry care, such as a washing machine or a tumble dryer. Specifically, such a laundry care appliance is understood to be a household laundry care appliance, i.e., a laundry care appliance used in the course of household management and with which laundry in typical household quantities is treated.

[0109] The laundry care appliance 1600 comprises an electric motor for driving a drum 1601 of the laundry care appliance 1600, e.g. an electric motor 100 as shown in Fig. 1 The laundry care appliance 1600 may also include a control unit 1603, which serves to control or even regulate the motor 100, for example, according to a set laundry care program. In addition to the control unit 1603, operating elements 1604 for operating the laundry care appliance 1600, usually via the control unit 1603, and a display 1605 for indicating the operating status of the laundry care appliance 1600 may also be present. The control unit 1603, operating elements 1604, and display 1605 may, for example, be located in (or behind) a dashboard or control panel 1602 of the laundry care appliance 1600.

[0110] The motor 100 can be fitted with inverter electronics 400 as per the above. Figures 2 to 13The described embodiments include: This converter electronics 400 can comprise: a mains supply circuit 410, 210 for supplying the laundry appliance with a mains voltage; a first DC intermediate voltage circuit 431, configured to rectify the mains voltage into a first intermediate circuit voltage for supplying a power stage 120 for phase control of the DC motor 480, 130; a second DC intermediate voltage circuit 432, configured to rectify the mains voltage into a second intermediate circuit voltage for supplying a switched-mode power supply 470, 310 for providing operating voltages for a control logic (110) for controlling the power stage (120).The converter electronics 400 includes a voltage regulator 490, which is configured to control the first DC intermediate voltage circuit 431 based on a measured value of the mains voltage 443 and to determine the measured value of the mains voltage 443 based on the second DC intermediate voltage circuit 432.

[0111] This solves the problem of the invention described at the beginning.

[0112] The scope of protection of the present invention is defined by the claims and is not limited by the features explained in the description or shown in the figures. Reference symbol list

[0113] 100 Electric motor with circuitry 110 Control logic 111 Control signals 120 Power stage 121 Motor-side phase signals 122 Power supply 123 Mains voltage 130 Electric motor unit 131 Stator with permanent magnet 132 Rotor 133 Position sensors or Hall sensors 134 Rotor position signals 200 Inverter electronics 210 Mains supply circuit 211 PFC choke 220 Resistor divider for tapping the mains voltage 221 Measuring point on the resistor divider for the mains voltage 230 Bridge rectifier circuit with four diodes 231 Smoothing capacitor on the bridge rectifier circuit 300 Inverter electronics 310 Switching power supply 320 Resistor divider for tapping the mains voltage 330 Bridge rectifier circuit with four diodes 331 Smoothing capacitor on the bridge rectifier circuit 321 Measuring point on the resistor divider for the mains voltage 400 Inverter electronics 410 Mains supply circuit 4211 Charging circuit 4222 Charging circuit 4233 Charging circuit 4311 Intermediate circuit or DC intermediate voltage circuit 4322 Intermediate circuit or DC intermediate voltage circuit 450 PFC choke 460 Resistor for measuring mains voltage 470 Switching power supply 4411 Measuring circuit for measuring mains voltage 4422 Measuring circuit for measuring mains voltage 4433 Measuring circuit for measuring mains voltage 4444 Measuring circuit for intermediate circuit measurement 480 Motor 490 Voltage regulator, e.g. microcontroller K103 Relay on 1st charging circuit 1201 First contact on relay K103 1202 Second contact on relay K103 1401 Shutdown time for switching off the engine 1502 Measured value of the mains voltage when measured at the motor-side DC intermediate voltage circuit 1501 Measured value of the mains voltage when measured at the DC intermediate voltage circuit of the switching power supply 1600Laundry care appliance 1601Drum 1602Control panel 1603Control unit 1604Operating elements 1605Display

Claims

1. Converter electronics unit (400) for a laundry care appliance (1600) with DC motor (480), wherein the converter electronics unit (400) comprises the following: a network supply switching circuit (410, 420) for supplying the laundry care appliance with a network voltage; a first DC intermediate voltage switching circuit (431), which is embodied to rectify the network voltage into a first intermediate circuit voltage for supplying a power level (120) for phase control of the DC motor (480, 130); a second DC intermediate voltage switching circuit (432) of a switched-mode power supply (470, 310) of the converter electronics unit (400), wherein the switched-mode power supply (470, 310) provides low operating voltages, wherein the second DC intermediate voltage switching circuit (432) is embodied to rectify the network voltage into a second intermediate circuit voltage for supplying the switched-mode power supply (470, 310) to provide operating voltages for a control logic (110) for actuating the power level (120), characterised in that the second DC intermediate voltage switching circuit (432) comprises an intermediate circuit capacitor (331) for smoothing the second intermediate circuit voltage, wherein the converter electronics unit (400) has a voltage regulator (490), which is embodied to regulate the first DC intermediate voltage switching circuit (431) on the basis of a measurement value of the network voltage (443) and to determine the measurement value of the network voltage (443) on the basis of the intermediate circuit capacitor (331) of the second DC intermediate voltage switching circuit (432).

2. Converter electronics unit (400) according to claim 1, characterised in that the DC motor (480) is a multiphase motor excited by a permanent magnet, in particular a synchronous motor excited by a permanent magnet, PMSM, or a brushless DC motor, BLDC, and wherein the converter electronics unit (400) comprises an inverter electronics unit for the multiphase motor excited by a permanent magnet.

3. Converter electronics unit (400) according to claim 1 or 2, characterised in that the voltage regulator is embodied to determine the measurement value of the network voltage (443) both during motor operation and during generator operation of the DC motor (480).

4. Converter electronics unit (400) according to one of the preceding claims, characterised in that the voltage regulator is embodied to regulate the first DC intermediate voltage switching circuit (431) on the basis of a voltage drop at the intermediate circuit capacitor (331) of the second DC intermediate voltage switching circuit (432).

5. Converter electronics unit (400) according to one of the preceding claims, characterised in that the converter electronics unit (400) comprises a resistor divider (320), which is embodied to determine a voltage drop at the intermediate circuit capacitor (331) of the second DC intermediate voltage switching circuit (432).

6. Converter electronics unit (400) according to one of the preceding claims, characterised in that the second DC intermediate voltage switching circuit (432) is electrically decoupled from the first DC intermediate voltage switching circuit (431).

7. Converter electronics unit (400) according to one of the preceding claims, characterised in that the converter electronics unit (400) comprises a first charging circuit (421) for charging a first phase of the DC motor (480), a second charging circuit (422) for charging a second phase of the DC motor (480) and a third charging circuit (423) for charging a third phase of the DC motor (480), wherein the converter electronics unit (400) possesses a relay (K103) for controlling a switchover of the first charging circuit (421) to the second (422) and to the third charging circuit (423); and wherein the converter electronics unit (400) is embodied to monitor the switchover of the first charging circuit (421) on the basis of a voltage difference at the relay (K103).

8. Converter electronics unit (400) according to claim 7, characterised in that the converter electronics unit (400) comprises a microcontroller (490), which is embodied to determine and evaluate the voltage difference at the relay (K103).

9. Converter electronics unit (400) according to claim 7 or 8, characterised in that a first contact (1201) of the relay (K103) is coupled to the network supply switching circuit (410) via a PFC choke (450); and wherein a second contact (1202) of the relay (K103) is coupled to the first DC intermediate voltage switching circuit (431).

10. Converter electronics unit (400) according to claim 9, characterised in that the converter electronics unit (400) comprises a first measurement switching circuit (441) for network voltage measurement at the first contact (1201) of the relay (K103) and a second measurement switching circuit (442) for network voltage measurement at the second contact (1202) of the relay (K103); and wherein the converter electronics unit (400) is embodied to monitor the switchover of the first charging circuit (421) on the basis of a difference between the network voltages measured by both measurement switching circuits (441, 442).

11. Converter electronics unit (400) according to claim 10, characterised in that the converter electronics unit (400) comprises a third measurement switching circuit (443) for network voltage measurement at the second DC intermediate voltage switching circuit (432); and wherein the converter electronics unit (400) is embodied to monitor the switchover of the first charging circuit (421) furthermore on the basis of the network voltage measured by the third measurement switching circuit (443).

12. Converter electronics unit (400) according to claim 11, characterised in that the converter electronics unit (400) comprises a fourth measurement switching circuit (444) for network voltage measurement at the first DC intermediate voltage switching circuit (431); and wherein the converter electronics unit (400) is embodied to stabilise the network voltage measured by the fourth measurement switching circuit (444) on the basis of the network voltage measured by the third measurement switching circuit (443).

13. Converter electronics unit (400) according to claim 12, characterised in that the four measurement switching circuits (441, 442, 443, 444) each comprise a resistor divider (220, 320) for determining a respective measurement value of the network voltage.

14. Laundry care appliance (1600) with DC motor and the converter electronics unit (400) according to one of the preceding claims.