JP6910754B2 - washing machine - Google Patents

Description

The present invention detects the current flowing through the stator windings of the motor, a washing machine comprising comprise equipment for vector control of the motor based on the detected current.

In Patent Document 1, the motor current is A / D converted and sampled at predetermined time intervals, the most distant current values are removed by the noise removing unit, and the remaining sample values are averaged by the averaging unit. The technology for outputting as digital information is disclosed. In this case, by setting the predetermined time shorter than the A / D conversion time and longer than the pulsed noise time width, the pulsed noise component can be removed without delaying the obtained information. There is.

Japanese Patent No. 5466482

However, Patent Document 1 assumes a configuration in which a noise removing unit and an averaging unit are built in an A / D converter, which cannot be realized by a microcomputer having a general configuration. Further, although it is possible to realize the functions of the noise removing unit and the averaging unit by software, a high-speed and expensive CPU is required to put them into practical use.

Therefore, without using a high-speed hardware CPU, Main after removing noise components contained in the detected current to provide a washing machines that can be performed precisely the vector control.

According to the washing machine of the embodiment, a drum for accommodating laundry, a motor in which a rotating shaft is connected to the drum to generate a rotational driving force for performing a washing operation, a drive circuit for driving the motor, and the like. When the current flowing through the stator windings of the motor is detected once for each carrier cycle of PWM control, and the motor is vector-controlled based on the current determined by averaging the current detection values over a plurality of cycles. It is provided with a motor control device that reduces the number of current detection values used for calculating the average value as the number of rotations of the motor increases.

FIG. 5 is a diagram schematically showing a drive control system of each motor in a washer / dryer according to the first embodiment. Longitudinal side view showing the configuration of a drum type washer / dryer Flowchart that outlines the operation of dehydration operation The figure which shows the change of the waveform by the presence or absence of averaging about the motor current measured by the current probe. A flowchart according to the second embodiment and schematically showing the operation of the dehydration operation. The figure explaining the case where the A / D conversion of the current is performed 4 times for each carrier cycle of PWM control. The figure explaining the case where the A / D conversion of the current is performed once for every carrier cycle. The figure which shows the change of the rotation speed and power consumption of a motor when the dehydration operation is consistently performed by vector control corresponding to 1st Embodiment. The figure which shows the change of the rotation speed and power consumption of the motor corresponding to 2nd Embodiment

(First Embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 4. FIG. 2 is a vertical sectional side view showing the configuration of a drum-type washer-dryer. The outer box 1 has a hollow shape having a front plate, a rear plate, a left side plate, a right side plate, a bottom plate, and a top plate, and the front plate of the outer box 1 is formed with a through-hole-shaped doorway 2. A door 3 is attached to the front plate of the outer box 1. The door 3 can be operated by the user from the front between the closed state and the open state. The door 3 is closed when the door 3 is closed, and the door 3 is opened when the door 3 is open. A water receiving tank 4 is fixed inside the outer box 1. The water receiving tank 4 has a cylindrical shape with a closed rear surface, and is arranged in an inclined state in which the axis CL descends from the front to the rear. The front surface of the water receiving tank 4 is open, and when the door 3 is closed, the door 3 closes the front surface of the water receiving tank 4 in an airtight state.

A drum motor 5 is fixed to the rear plate of the water receiving tank 4 so as to be located outside the water receiving tank 4. The drum motor 5 is composed of a DC brushless motor whose speed can be controlled, and the rotating shaft 6 of the drum motor 5 projects into the water receiving tank 4. The rotating shaft 6 is arranged so as to be overlapped with the axis CL of the water receiving tank 4, and the drum 7 is fixed to the rotating shaft 6 located inside the water receiving tank 4. The drum 7 has a cylindrical shape with a closed rear surface, and rotates integrally with the rotating shaft 6 in the operating state of the drum motor 5. The front surface of the drum 7 faces the doorway 2 from the rear via the front surface of the water receiving tank 4, and inside the drum 7, the door 3 is opened and the doorway 2 and the front surface of the water receiving tank 4 and the drum 7 are connected from the front. Laundry is taken in and out through the front.

A plurality of through holes 8 are formed in the drum 7, and the internal space of the drum 7 is connected to the internal space of the water receiving tank 4 through each of the plurality of through holes 8. A plurality of baffles 9 are fixed to the drum 7. Each of the plurality of baffles 9 moves in the circumferential direction around the axis CL in response to the rotation of the drum 7, and the laundry in the drum 7 is caught by each of the plurality of baffles 9. While moving in the circumferential direction, it is agitated by falling due to gravity.

A water supply valve 10 is fixed inside the outer box 1. The water supply valve 10 has an inlet and an outlet, and the inlet of the water supply valve 10 is connected to a water faucet. The water supply valve 10 is driven by a water supply valve motor 11 (see FIG. 2), and the outlet of the water supply valve 10 is switched between an open state and a closed state according to the amount of rotation of the water supply valve motor 11. The outlet of the water supply valve 10 is connected to the water injection case 12, tap water is injected into the water injection case 12 through the water supply valve 10 when the water supply valve 10 is open, and tap water is injected when the water supply valve 10 is closed. Not injected into case 12. The water injection case 12 is fixed inside the outer box 1 at a position higher than the water receiving tank 4, and has a tubular water injection port 13. The water injection port 13 is inserted inside the water receiving tank 4, and tap water injected into the water injection case 12 from the water supply valve 10 is injected into the inside of the water receiving tank 4 from the water injection port 13.

The upper end of the drain pipe 14 is connected to the water receiving tank 4 at the bottom, and the drain valve 15 is interposed in the drain pipe 14. The drain valve 15 is driven by a drain valve motor 16 (see FIG. 2), and is switched between an open state and a closed state according to the amount of rotation of the drain valve motor 16. In the closed state of the drain valve 15, tap water injected into the water receiving tank 4 from the water injection port 13 is stored in the water receiving tank 4, and in the open state of the drain valve 15, tap water in the water receiving tank 4 passes through the drain pipe 14. It is discharged to the outside of the water receiving tank 4.

A main duct 17 is fixed to the bottom plate of the outer box 1 at a position below the water receiving tank 4. The main duct 17 has a tubular shape that points in the front-rear direction, and the lower end of the front duct 18 is connected to the front end of the main duct 17. The front duct 18 has a tubular shape that points in the vertical direction, and the upper end portion of the front duct 18 is connected to the internal space of the water receiving tank 4 at the front end portion of the water receiving tank 4. A fan casing 19 is fixed to the rear end of the main duct 17. The fan casing 19 has a through-hole-shaped intake port 20 and a tubular exhaust port 21, and the internal space of the fan casing 19 is connected to the internal space of the main duct 17 via the intake port 20.

A fan motor 22 is fixed to the fan casing 19 at a position outside the fan casing 19. The fan motor 22 has a rotating shaft 23 protruding inside the fan casing 19, and the fan 24 is fixed to the rotating shaft 23 at a position inside the fan casing 19. The fan 24 is a centrifugal type that sucks air from the axial direction and discharges it in the radial direction. The intake port 20 of the fan casing 19 faces the fan 24 from the axial direction of the fan 24, and the exhaust port 21 of the fan casing 19 Faces the fan 24 from the radial direction of the fan 24.

The lower end of the rear duct 25 is connected to the exhaust port 21 of the fan casing 19. After this, the rear duct 25 has a tubular shape that points in the vertical direction, and the upper end portion of the rear duct 25 is connected to the internal space of the water receiving tank 4 at the rear end portion of the water receiving tank 4. The rear duct 25, the fan casing 19, the main duct 17, the front duct 18, and the water receiving tank 4 form an annular circulation duct 26 having the internal space of the water receiving tank 4 as a start point and an end point, respectively. When the fan motor 22 is operated in the closed state, the air in the water receiving tank 4 is sucked into the fan casing 19 from the front duct 18 through the main duct 17 based on the fan 24 rotating in a certain direction. , It is returned to the water receiving tank 4 from the inside of the fan casing 19 through the rear duct 25.

A compressor 27 is fixed inside the outer box 1. The compressor 27 is arranged outside the circulation duct 26, and has a discharge port for discharging the refrigerant and a suction port for sucking the refrigerant. The compressor 27 is driven by a comp motor 28 (see FIG. 2), and the comp motor 28 is composed of a DC brushless motor whose speed can be controlled.

A capacitor (condenser) 29 is fixed inside the main duct 17. The condenser 29 heats air, and is configured by fixing each of a plurality of plate-shaped heating fins 31 in a contact state on the outer peripheral surface of one refrigerant pipe 30 that bends in a meandering shape. .. The refrigerant pipe 30 of the condenser 29 is connected to the discharge port of the compressor 27, and the refrigerant discharged from the discharge port of the compressor 27 enters the refrigerant pipe 30 of the condenser 29 in the operating state of the compressor 28.

FIG. 1 schematically shows a drive control system for a drum motor 5, a fan motor 22, and a comp motor 28. The inverter circuit 34 is configured by connecting six IGBTs (switching elements) 35a to 35f in a three-phase bridge, and flywheel diodes 36a to 36f are connected between the collector and the emitter of each IGBT 35a to 35f. There is. Each phase output terminal of the inverter circuit 34 is connected to each phase winding of the drum motor 5.

The emitters of the IGBTs 35d, 35e and 35f on the lower arm side are connected to the ground via the shunt resistors 37u, 37v and 37w. Further, the common connection point between the emitters of the IGBTs 35d, 35e and 35f and the shunt resistors 37u, 37v and 37w is connected to the input terminal of the control circuit (microprocessor, microcomputer) 42A.

Although not shown, the inside of the control circuit 42A is configured to include an operational amplifier and the like so that the terminal voltage of the shunt resistors 37u to 37w is amplified by the level shift circuit and the output range of the amplified signal is within the positive side (for example). , 0- + 3.3V) Gives a bias. Further, the control circuit 42A has a function of detecting an overcurrent in order to prevent the circuit from being destroyed when the upper and lower arms of the inverter circuit 34 are short-circuited.

An inverter circuit 38 and a shunt resistor 39 (u, v, w) having the same configurations are arranged for the fan motor 22, and the inverter circuit 40 and the shunt resistor 41 (u) are arranged for the comp motor 28. , V, w) are arranged. The inverter circuits 38 and 40 are controlled by another control circuit 42B (microprocessor, microcomputer), short-circuit control means), and the control circuits 42A and 42B are capable of bidirectional communication by serial communication. ..

A drive power supply circuit 43 is connected to the input side of the inverter circuits 34, 38, 40. The drive power supply circuit 43 is connected to a 100 V AC power supply via a reactor (inductive reactor) 44 on one end side, and is composed of a diode bridge and a full-wave rectifier circuit 45 and an output of the full-wave rectifier circuit 45. It is provided with two capacitors 46a and 46b connected in series on the side. The common connection point of the capacitors 46a and 46b is connected to one of the input terminals of the full-wave rectifier circuit 45. When the boosting operation using the reactor 44 described later is not performed, the drive power supply circuit 43 double-voltage full-wave rectifies the 100 V AC power supply and supplies a DC voltage of about 280 V to the inverter circuit 34 and the like.

Another full-wave rectifier circuit 47 (short-circuit means), which is also composed of a diode bridge, is connected in parallel to the input terminal of the full-wave rectifier circuit 45, and is connected between the output terminals of the full-wave rectifier circuit 47. , IGBT48 (short circuit means) is connected. The control circuit 42B performs on / off control of the IGBT 48. The drive power supply circuit 43 also includes a full-wave rectifier circuit 47 and an IGBT 48. Further, an AC voltage detector 60 is connected to the input terminal of the full-wave rectifier circuit 45, and the output terminal of the AC voltage detector 60 is connected to the input terminals of the control circuits 42A and 42B.

A series circuit of resistors 49a and 49b and a series circuit of resistors 50a and 50b are connected between the input terminals of the inverter circuits 34 and 38, respectively, and their common connection points are connected to the input terminals of the control circuits 42A and 42B, respectively. It is connected. The control circuits 42A and 42B detect the drive power supply voltage input to the inverter circuits 34 and 38 by referring to the voltage at each of the common connection points.

Further, in order to detect the rotor position on the drum motor 5, for example, a position sensor 51 (u, v, w) composed of a Hall IC or the like is arranged, and the sensor signal output by the position sensor 51 is , Is given to the control circuit 42A. Further, a current sensor 52 including, for example, a current transformer (CT) is inserted between the AC power supply and the reactor 44, and the sensor signal output by the current sensor 52 is given to the control circuit 42B. ..

The control circuits 42A and 42B detect the currents flowing in the respective phase windings of the motors 5, 22 and 28, estimate the phase θ and the rotation angle velocity ω of the secondary rotating magnetic field based on the current values, and three. The exciting current component Id and the torque current component Iq are obtained by performing orthogonal coordinate conversion and dq (direct-quadrature) coordinate conversion of the phase current. Then, when the speed commands are given from the outside, the control circuits 42A and 42B generate current commands Idref and Iqref based on the estimated phase θ, rotational angular velocity ω, and current components Id and Iq, and generate current commands Idref and Iqref, which are used as voltage commands Vd and Vq. When converted to, Cartesian coordinate conversion and three-phase coordinate conversion are performed. Finally, the drive signal is generated as a PWM signal and output to the phase windings of the motors 5, 22 and 28 via the inverter circuits 34, 38 and 40.

In the above configuration, the inverter circuit 34, the control circuits 42A and 42B, and the drive power supply circuit 43 constitute the drive device 61.
Next, the operation of this embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the control contents in the case of performing the dehydration operation with respect to the part related to the gist of the present embodiment. When the dehydration operation is started, first, the number of samples of the A / D conversion value used for the moving average calculation for determining the current values of the U, V, and W phases is set to "4" (S1). Here, A / D conversion of each phase current is performed for each PWM control cycle. The control cycle is, for example, 64 μsec. Then, when the rotor positioning process is performed (S2, S3; YES), vector control is started (S4). Further, when the motor 5 is started, drive control is performed using the position sensor 51 (S5).

When the rotation speed of the motor 5 becomes, for example, 30 rpm or more (S6; YES), the sensorless drive system is switched to (S7), and when the rotation speed becomes, for example, 200 rpm or more (S8; YES), the current value of each phase is determined. The number of samples used for the moving average calculation is reduced to "3" (S9). Subsequently, when the rotation speed becomes, for example, 300 rpm or more (S10; YES), the number of samples is reduced to "2" (S11), and when the rotation speed becomes, for example, 500 rpm or more (S12; YES), the moving average calculation is not performed and the number of samples is not performed. Is set to "1", that is, the sample value A / D converted at that time is used as it is as a current value for control (S13).

When noise is mixed in the A / D converted current value during vector control, it affects the control calculation, so abnormal noise may be generated from the motor 5, or an excessive current may flow and an overcurrent error may be detected. , The IGBT 35 constituting the inverter circuit 34 may be damaged. The cause of noise is the switching operation of the elements used in the IGBT 35 and the 5V and 15V power supplies for control.

FIG. 4 shows the change in waveform of the motor current measured by the current probe depending on the presence or absence of the average. As shown in the figure, it can be seen that the noise of the current waveform is reduced by determining the current value used for the vector control by the moving average. In addition, the abnormal noise actually generated by the motor has also been reduced.

As described above, according to the present embodiment, the control circuit 42A detects each phase current flowing through the stator winding of the motor 5, and sets the motor 5 based on the current determined by averaging a plurality of detected current values. During vector control, the number of current detection values used in the calculation of the average value is reduced as the rotation speed of the motor 5 increases. As a result, noise can be removed by averaging the current values with a margin when the rotation speed of the motor 5 increases without using a microcomputer capable of executing high-speed processing in the control circuit 42A. Then, it is possible to avoid the generation of abnormal noise from the motor 5 and the occurrence of an overcurrent error.

(Second Embodiment)
Hereinafter, the same parts as those in the first embodiment are designated by the same reference numerals, description thereof will be omitted, and different parts will be described. FIG. 6 is an example assuming that the number of samples used for the moving average calculation is “4” and sampling is performed four times in each carrier cycle of PWM control. In this case, A / D conversion is performed four times during the period when the lower phase arm of the inverter circuit 34 is ON, but in order to avoid the influence of noise, sampling is performed near the center during the ON period. Is preferable. Then, the processing speed of the CPU and the A / D converter constituting the control circuit 42 is often insufficient.

On the other hand, as in the first embodiment shown in FIG. 7, if sampling is performed once for each carrier cycle and the moving average calculation is performed over a plurality of cycles, the A / D conversion process has a sufficient margin. Can be done with. However, in this case, since a time delay occurs in the processing of the current value, there is no problem when the rotation speed of the motor 5 is low, but when the rotation speed is high, the processing delay affects the processing.

Therefore, in the second embodiment, the vector control is switched to the voltage / phase control when the rotation speed of the motor 5 rises to some extent. The configuration for this purpose is disclosed in, for example, Japanese Patent No. 3651595. In addition, the moving average calculation of the current value also stops as the voltage / phase control is switched. In vector control, since PI (proportional integration) control is included in the control loop, the influence of noise contained in the current value appears remarkably. On the other hand, since PI control is not performed in voltage / phase control, there is no problem because the current fluctuation is small even if some noise is included in the current value.

In the flowchart shown in FIG. 5, steps S21 to S23 are executed instead of steps S8 to S13. When step S7 is executed, when the rotation speed of the motor 5 reaches the threshold value of, for example, 280 rpm or more (S21; YES), the moving average calculation is not performed as in step S13, and the sample value A / D converted at that time is used as it is. It is used for control as a current value (S22). Then, when the control method is switched from vector control to voltage / phase control (S23), the process proceeds to step S14.

FIG. 8 corresponds to the first embodiment, in which the dehydration operation is consistently performed by vector control, and the power consumption that peaks when the rotation speed of the motor 5 reaches 1650 rpm is 670 W. When the moving average calculation is not performed on the current value, the current value is 800 W, and a time delay occurs due to the moving average calculation, and the effect becomes remarkable at high speed rotation, resulting in a decrease in power, that is, a decrease in motor output. On the other hand, FIG. 9 shows the case of the dehydration operation corresponding to the second embodiment. By switching to the voltage / phase control and stopping the moving average calculation process, the peak power consumption is maintained at about 800 W, which is the same as the above. There is.

As described above, according to the second embodiment, the control circuit 42A performs voltage / phase control instead of vector control when the rotation speed of the motor 5 exceeds a preset threshold value. As a result, even when the moving average calculation process is stopped in the high-speed rotation region of the motor 5, the fluctuation of the current due to the influence of noise can be reduced.

(Other embodiments)
The control circuits 42A and 42B may be integrated into one control circuit.
The semiconductor switching element is not limited to the IGBT, and a bipolar transistor or MOSFET may be used.
Similar control may be applied to the fan motor 22 and the comp motor 28.
The maximum value of the number of samples used in the moving average calculation and the pattern of decrease may be appropriately changed according to the individual design.
The setting of the threshold value of the rotation speed is also an example, and may be appropriately changed according to the individual design.
It may be applied to a washing machine that does not have a drying function.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

In the drawings, 5 is a drum motor, 42 is a control circuit, 34, 38, and 40 are inverter circuits, and 61 is a drive device.

Claims (2)

A drum to store the laundry and
A motor in which a rotating shaft is connected to this drum to generate a rotating driving force for washing operation,
The drive circuit that drives this motor and
When the current flowing through the stator winding of the motor is detected once for each carrier cycle of PWM control and the motor is vector-controlled based on the current determined by averaging the current detection values over a plurality of cycles. A washing machine including a motor control device that reduces the number of current detection values used in calculating the average value as the number of rotations of the motor increases. A drum to store the laundry and
A motor in which a rotating shaft is connected to this drum to generate a rotating driving force for washing operation,
The drive circuit that drives this motor and
The current flowing through the stator winding of the motor is detected once for each carrier cycle of PWM control, and the motor is vector-controlled based on the current determined by averaging the current detection values over a plurality of cycles.
Becomes equal to or larger than the threshold rotational speed of the motor is preset, the instead of the vector control, once detected current row cormorants washing voltage and phase control based on濯機for each of the carrier cycle.

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