TW202108840A - washing machine - Google Patents

Abstract

This drum-type washing machine comprises: a rotary tub; a motor which rotationally drives the rotary tub; an inverter circuit which converts direct current into alternating current and drives the motor; and a current detection unit which detects the current flowing through the motor. The drum-type washing machine further comprises: a low-pass filter processing unit which performs low-pass filter processing on the current detected by the current detection unit and outputs the low-pass filtered value as a processed current value; an overload detection unit which detects the overload state of the motor; and a control unit which transmits a motor drive command to the inverter circuit and controls the motor through the inverter circuit. Further, the overload detection unit determines the overload state of the motor on the basis of the processed current value output by the low-pass filter processing unit, and the control unit controls the rotational drive of the motor on the basis of the determination result of the overload detection unit.

Description

washing machine

This disclosure relates to a washing machine.

In the past, as disclosed in Japanese Patent Laid-Open No. 11-239688, a washing machine was proposed that uses a thermistor to detect the temperature of the windings of the stator.

This washing machine is equipped with: a water tank; a rotating tank, which is rotatably arranged inside the water tank; a motor, which drives the rotating tank to rotate; and a control circuit, a control motor, and the like. The motor is composed of a rotor with a ring-shaped permanent magnet and a stator with three-phase windings, and a thermistor, which is a temperature detection mechanism, is arranged near the windings of the stator. The control circuit uses the thermistor voltage to detect the temperature of the stator winding.

However, parts such as thermistors are expensive, and there is a problem that the manufacturing cost becomes higher.

The present disclosure provides a washing machine that improves the safety of the motor through a low-cost structure.

The washing machine in the present disclosure includes: a rotating tank; a motor to drive the rotating tank in rotation; a commutation circuit to convert a direct current into an alternating current and drive the motor; and a current detection unit to detect the current flowing in the motor. In addition, it is equipped with: a low-pass filter unit, which performs low-pass filter processing on the current detected by the current detection unit, and outputs the low-pass filter processed value as the processed current value; an overload detection unit, which detects motor failure Load status; and the control unit, which sends a motor drive command to the inverter circuit, and controls the motor through the front inverter circuit. In addition, the overload detection unit determines the overload state of the motor based on the processed current value output by the low-pass filter unit, and the control unit controls the rotation drive of the motor based on the determination result of the overload detection unit.

The washing machine in the present disclosure improves the safety of the motor by using a low-cost structure.

The form used to implement the invention

Hereinafter, the embodiments will be described in detail while referring to the drawings. In addition, the present invention is not limited by the attached drawings and the following description. (First Embodiment)

Hereinafter, the first embodiment will be described using FIGS. 1 to 6. (Basic composition of washing machine)

Fig. 1 is a longitudinal sectional view showing a schematic configuration of a washing machine in the first embodiment.

As shown in Fig. 1, in the washing machine body 1, a bottomed cylindrical water tank 2 is elastically supported by a suspension structure (not shown). The water tank 2 is supported by inclining its axis direction from the front side (left side in FIG. 1) to the back side (right side in FIG. 1). A rotating tank 3 formed in a bottomed cylindrical shape is rotatably arranged in the water tank 2. On the inner wall surface of the rotating tank 3 are formed a plurality of water passing holes 6 for allowing washing water to pass through the inside and outside of the rotating tank 3, and a plurality of stirring protrusions (not shown) for stirring the clothes.

A circular fluid balancer 15 is arranged on the front side of the rotating tank 3. The fluid balancer 15 is divided into a plurality of storage chambers (not shown) by a plurality of partition plates provided in the circumferential direction, and a communication hole is formed in each partition plate. A liquid with a high specific gravity such as calcium chloride is stored in the fluid balancer 15. The liquid can move from a certain storage chamber to the storage chamber of the partition wall through the communication hole. When the laundry inside the rotating tub 3 is shifted during the washing operation, an eccentric load is generated in the rotating tub 3. The liquid is moved to the opposite side of the eccentric load to correct the deviation of the center of gravity and reduce the vibration noise of the rotating tank 3.

On the front side of the washing machine body 1 is formed a clothes entrance 4 which leads to the open end of the rotating tank 3, and the clothes entrance 4 is covered by a door 5 open and close. The user can take out and put the laundry into the rotating tank 3 through the clothes entrance 4 with the door 5 opened. An input setting unit 25 (refer to FIG. 2) that is an operation display panel 10 is provided above the clothes entrance 4, that is, on the front surface of the washing machine body 1. The user can set a desired operation stroke by operating the operation display panel 10.

The motor 7 is arranged in the lower part of the water tank 2. The motor 7 is connected to a rotation center shaft 17 provided at the bottom of the rotation tank 3 through a pulley 14 and a belt 16. The rotational driving force of the motor 7 is transmitted to the rotating groove 3 through the pulley 14 and the belt 16, and the rotating groove 3 is rotated in the forward or reverse direction.

The water injection pipe 8 is pipe connected to the upper part of the water tank 2, and the drain pipe 9 is pipe connected to the lower part of the water tank 2. The water injection pipe 8 and the drain pipe 9 are provided with a water supply valve 27 and a drain valve 28 in a switchable manner. By opening the water supply valve 27 and the drain valve 28 respectively, water filling and draining into the water tank 2 are performed. (Configuration of motor drive device)

Fig. 2 is a block diagram showing the circuit configuration of the washing machine in the first embodiment.

As shown in FIG. 2, a rectifier 21, a choke coil 22, and a smoothing capacitor 23 are provided in the circuit for driving the motor 7. The AC voltage of the mains power 20 is rectified by the rectifier 21. The rectified AC power is converted into a DC voltage by a smoothing circuit formed by the choke coil 22 and the smoothing capacitor 23. Therefore, the converted DC voltage is applied to the converter circuit 24.

The commutation circuit 24 is formed by a three-phase full-bridge commutation circuit, and the aforementioned three-phase full-bridge commutation circuit is formed by six power switching semiconductors 24a-24f and anti-parallel diodes. In this embodiment, the commutation circuit 24 is constituted by a smart power module (hereinafter referred to as IPM). The smart power module has built-in insulated gate bipolar transistors (IGBT), anti-parallel diodes, And its drive circuit and protection circuit. The motor 7 is connected to the output terminal of the inverter circuit 24. In addition, the inverter circuit 24 controls the operations of the water supply valve 27, the drain valve 28, the blower fan 12, and the heat pump 29 by the load drive unit 26 based on operation instructions or monitoring information.

The motor 7 is a brushless motor. The motor 7 is provided with a permanent magnet that constitutes a rotor; a stator; and a rotor position detection unit, which is composed of three Hall ICs (Hall ICs), Hall IC 30a, Hall IC 30b, and Hall IC 30c. The Hall IC30a, Hall IC30b, and Hall IC30c detect the relative position of the permanent magnet and the fixed element (rotating element position) and output the reference signal every 60 degrees of electrical angle.

The current detection mechanism in this embodiment is composed of a shunt resistor (not shown), and is provided in the commutation circuit 24. The current detection mechanism detects the motor currents Iu, Iv, and Iw of the motor 7.

The control unit 31 is composed of a microcomputer, a commutation control timer (PWM timer) built in the microcomputer, a high-speed A/D conversion circuit, and a memory circuit (ROM, RAM), and the like. The control unit 31 detects the electrical angle from the output signals of the Hall IC 30a, the Hall IC 30b, and the Hall IC 30c constituting the rotor position detection unit. In addition, the control unit 31 performs three-phase/two-phase dq conversion and two-phase/three-phase dq inverse conversion. The aforementioned three-phase/two-phase dq conversion is decomposed into a current component Id corresponding to magnetic flux and a current component Iq corresponding to torque. The aforementioned two-phase/three-phase dq reverse conversion is to convert the voltage component Vd corresponding to the magnetic flux and the voltage component Vq corresponding to the torque into three-phase motor drive control voltages Vu, Vv, Vw, and the control unit 31 responds to The three-phase motor drive control voltages Vu, Vv, and Vw are used to perform PWM control on the switching of the IGBT of the drive circuit 32. Thereby, the control unit 31 controls the energization of the three-phase windings of the stator, that is, the winding 7a, the winding 7b, and the winding 7c, so that the motor 7 is rotated at the required number of rotations.

In this embodiment, the microcomputer of the control unit 31 functions as the low-pass filter processing unit 33 and the overload detection unit 34. The detailed operations of the low-pass filter processing unit 33 and the overload detection unit 34 will be described later. (Basic operation of washing operation)

The user opens the door 5, throws the laundry and detergent into the rotating tank 3, and operates the input setting unit 25, that is, the operation display panel 10 to start the operation. When the operation starts, the control unit 31 opens the water supply valve 27 and pours water into the water tank 2. When the predetermined water level is reached, the control unit 31 closes the water supply valve 27 and starts the cleaning operation.

In the washing operation, the control unit 31 rotates the rotating tank 3 by rotating the motor 7. The laundry contained in the rotating tank 3 is lifted in the rotating direction by the stirring protrusions along with the rotation of the rotating tank 3, and dropped from an appropriate height position to be stirred. In this way, in the washing action, dirt is removed by beating and washing the laundry by lifting and falling.

When a predetermined time has passed during the washing operation, the control unit 31 opens the drain valve 28 and drains the dirty washing liquid from the drain line 9. Next, the control unit 31 dehydrates the washing liquid contained in the laundry by a dehydration operation of rotating the rotating tub 3 at a high speed. (Relationship between motor current value and motor winding temperature)

In the case of excessively accommodating clothes in the rotating tank 3, there is a problem that the clothes are twisted or bitten during the rotating operation of the rotating tank 3, which causes an excessive load on the motor 7. In a state where an excessive load is applied to the motor 7, that is, a motor overload state, the current value flowing to the motor 7, that is, the motor current value becomes higher than the motor current value during the general washing operation.

Fig. 3 is a characteristic diagram of motor winding temperature in each current value of the motor of the washing machine in the first embodiment.

The motor winding temperature refers to the temperature of the windings 7a, 7b, and 7c of the three-phase windings. In FIG. 3, the horizontal axis shows the operating time, and the vertical axis shows the motor winding temperature, and the change of the motor winding temperature in each current value is displayed. Each current value is set to a predetermined value so that the motor current A, the motor current B, the motor current C, and the motor current D become smaller in this order.

Generally speaking, the motor winding temperature rises in proportion to the square of the motor current value. When a fixed time passes, the motor winding temperature is saturated. In the case where the saturation temperature exceeds the heat-resistant temperature of the motor windings, there is a concern that the motor windings will burn out. Therefore, it is necessary to control the motor current value so that the motor winding temperature does not exceed the heat-resistant temperature.

In this embodiment, the current value that may cause the winding saturation temperature to exceed the heat-resistant temperature of the motor winding is experimentally measured in advance, and a predetermined threshold value is set based on the current value. When the motor current value exceeds a predetermined threshold value and a predetermined time has elapsed, it is defined as a motor overload state. (Overload status detection processing and commutation control processing)

Fig. 4 is a flowchart of the overload state detection process of the motor of the washing machine in the first embodiment, and Fig. 5 is a flowchart showing the commutation control process of the motor of the washing machine in the first embodiment.

During the washing operation, the control unit 31 starts the overload state detection process (step S101), and starts the commutation control process shown in FIG. 5. In addition, the two processes are performed in parallel and independently, and are executed repeatedly at respective time intervals.

At the beginning, an explanation will be given to the detection processing of the overload state.

As shown in FIG. 4, when the overload detection unit 34 starts the overload state detection process (step S101), it performs a low-pass filter process of the motor current value (step S102).

The low-pass filter processing in this embodiment calculates the amount of change between the previous motor current value and the current value of the motor current, reduces the amount of change by a fixed ratio, and adds it to the current detected last time. These processes are arithmetic processing performed by the low-pass filter processing unit 33 which is a microcomputer. Generally speaking, it is known that the current value flowing when the motor is started instantly becomes a larger current value and slowly converges to a fixed value. By performing low-pass filter processing, the component of the input current is removed from the measured value of the motor current value, which can suppress the false detection of the overload state caused by the instantaneous flow of a large current. In addition, the time constant of the low-pass filter is set to approximately the same time (for example, 10 seconds) as the ON time of the motor drive.

Next, the overload detection unit 34 compares the motor current value after the low-pass filter processing with the threshold value α to determine whether or not it is in the motor overload state (step S103). In S103, when the motor current value is lower than α (step S103, No), or when the motor current value is above α and the predetermined time t1 has not elapsed (step S103, No), the overload state detection is ended Processing (step S107). This suppresses the erroneous detection of a motor overload state when the motor current value instantaneously becomes a value greater than α.

In step S103, when the motor current value is above α and the predetermined time t1 has elapsed (step S103, Yes), the overload detection unit 34 sets the motor overload state, that is, sets the motor to the overload state (step S103). S104).

As mentioned above, in the motor overload state, there is a concern that the temperature of the motor winding exceeds the heat-resistant temperature. Therefore, it is necessary to cool the motor windings until the motor current value after the low-pass filtering process becomes below a predetermined value. In the present embodiment, a threshold value β, which is one-third of the threshold value α, is provided, and as long as the motor current value becomes less than or equal to the threshold value β, it is determined as a non-motor overload state.

The overload detection unit 34 compares the motor current value after the low-pass filter processing with the threshold value β (step S105). In step S105, when the motor current value exceeds the threshold β (step S105, No), the overload state detection processing is ended (step S107).

In step S105, when the motor current value is below the threshold β (step S105, Yes), the motor overload state is eliminated, that is, the determination of the motor overload state is cancelled (step S106). After that, the overload state detection processing is ended (step S107).

Next, the commutation control process will be described.

As shown in FIG. 5, the control unit 31 starts the commutation control process (step S201). The control unit 31 issues a motor drive command to cause the drive circuit 32 to perform PWM control on the switching of the IGBT (step S202). Thereby, the motor 7 rotates and drives the rotating tank 3 in accordance with the motor drive command.

In step S203, when the motor overload state is set (step S203, Yes), the control unit 31 causes the drive circuit 32 to stop PWM output (step S204). After that, the commutation control process is ended (step S205). When the motor overload state is not set (step S203, No), the commutation control process is ended (step S205).

Next, the characteristics of the motor current value (after the low-pass filter processing) and the motor drive command in this embodiment will be described.

Fig. 6 is a diagram showing the relationship between the motor current (after low-pass filter processing) and the motor drive command of the washing machine in the first embodiment. The horizontal axis is the operating time, the left vertical axis is the motor current value after low-pass filtering, and the right vertical axis is the motor drive command.

The stirring time limit during washing is to set 10 seconds in the ON state and 1 second in the OFF state as one cycle, and the stirring action is carried out while reversing left and right in each cycle. At this time, the motor current value after the low-pass filter process rises while vibrating up and down when stirring is ON, and gradually decreases when stirring is OFF. In the overload state detection process shown in FIG. 4, when the motor overload state is set (step S104), in the commutation control process shown in FIG. 5, the PWM output is stopped (step S204). During the period when the PWM output is stopped, since the motor current does not flow, the motor current value after the low-pass filtering process gradually decreases.

It is known that as the motor current value after the low-pass filtering process becomes larger, the time it takes to decrease the current value becomes longer. Therefore, when the motor current value is large, the time until the motor current value becomes less than or equal to the threshold β becomes longer, and as a result, the period during which the motor drive is stopped becomes longer. In this way, even if the motor current value is greater than or equal to the threshold value α and the motor current value rises rapidly before the predetermined time t1 elapses, the cooling time is increased in accordance with the motor current value, so that the motor winding temperature can be increased. Really lower.

When the motor current value after the low-pass filter processing is lower than the threshold β, the motor overload state is eliminated in the overload state detection process shown in FIG. 4 (step S106). Then, in the commutation control process shown in FIG. 5, PMW output is restarted (step S202).

As described above, by detecting the motor overload condition based on the motor current after the low-pass filter processing, and keeping the motor winding temperature within the heat-resistant temperature, the safety function of the motor can be realized at a lower price than before. (Role, etc.)

The drum-type washing machine in this embodiment includes: a rotating tank 3; a motor 7 to rotate the rotating tank 3; a converter circuit 24 to convert a direct current into an alternating current to drive the motor 7; and a current detection unit to detect the flow in the motor 7 of the current. It also includes a low-pass filter processing unit 33 that performs low-pass filter processing on the current detected by the current detection unit, and outputs the low-pass filter processed value as the processed current value; and an overload detection unit 34 that detects The overload state of the motor 7; and the control unit 31 sends a motor drive command to the inverter circuit 24, and controls the motor 7 through the inverter circuit 24.

In addition, the overload detection unit 34 determines that the motor 7 is in an overload state based on the processed current value output by the low-pass filter processing unit 33, and the control unit 31 controls the motor based on the determination result of the overload detection unit 34 7's rotary drive.

With this structure, there is no need to install other parts such as a temperature fuse or a thermistor, and the increase in the temperature of the motor winding can be detected from the change in the motor current value. Therefore, an excessive increase in the temperature of the motor winding is suppressed, and the safety of the motor can be realized at low cost.

Also, as in the present embodiment, the overload detection unit 34 may determine that the motor 7 is in an overload state when the processed current value is equal to or greater than the first value, that is, and a predetermined time has elapsed. If the current value of is smaller than the first value, that is, the second value, that is, β, the motor overload state is released.

According to this configuration, the time from when the motor 7 is determined to be in the overload state and the drive is stopped until the motor current value is lower than β becomes longer as the motor current value increases. Therefore, when there is a high possibility that the temperature of the windings will increase, a longer heat release time can be spared, so that the safety of the motor can be realized at a low cost. (Second Embodiment)

The washing machine of the second embodiment is different from the washing machine 100 of the first embodiment in the commutation control process during the spin-drying operation. Hereinafter, the second embodiment will be described using the same reference numerals for the same configuration as the first embodiment.

Fig. 7 is a flowchart showing the commutation control process of the motor of the washing machine in the second embodiment.

The control unit 31 starts the commutation control process (step S301). The control unit 31 determines whether a PWM output stop history is provided, that is, whether a history of stopping due to a motor overload state in the previous commutation control process is set (step S302). When the PWM output stop history is provided (step S302, Yes), a motor drive command is sent to reduce the number of rotations of the motor 7 (step S303). For example, when an overload state is detected when the number of spins is 1400 rpm, the number of spins is reduced to 1300 rpm in the next commutation control process.

In step S304, the control unit 31 cancels the PWM output stop history, that is, cancels the history of the stop due to the motor overload state in the previous commutation control process (step S304).

In step S305, the drive circuit 32 follows the motor drive command received from the control unit 31 to perform PWM output (step S305).

In step 306, the control unit 31 refers to the motor overload state (S306). When the motor overload state is set (step S306, Yes), the drive circuit 32 is caused to stop the PWM output (step S307), and the PWM output stop history is set (step S308). After that, the commutation control process is ended (step S309). When the predetermined time has elapsed, the next commutation control process is started (step S301).

By repeating the above commutation control process (step S301 to step S309), the number of rotations of the motor 7 is adjusted so that the motor current value becomes equal to or less than the overload current value.

Especially in the dehydration operation, since the flux weakening control is performed in accordance with the increase of the induced voltage of the motor, the motor current increases as the number of rotations increases. Therefore, by adjusting the number of rotations of the motor 7, an excessive increase in the temperature of the motor winding can be effectively suppressed. (Role, etc.)

The drum-type washing machine in this embodiment includes: a rotating tank 3; a motor 7 to rotate the rotating tank 3; a converter circuit 24 to convert a direct current into an alternating current to drive the motor 7; and a current detection unit to detect the flow in the motor 7 of the current. It also includes a low-pass filter processing unit 33 that performs low-pass filter processing on the current detected by the current detection unit, and outputs the low-pass filter processed value as the processed current value; and an overload detection unit 34 that detects The overload state of the motor 7; and the control unit 31 sends a motor drive command to the inverter circuit 24, and controls the motor 7 through the inverter circuit 24. In addition, the overload detection unit 34 determines that the motor 7 is in the overload state based on the processed current value output by the low-pass filter processing unit 33, and the control unit 31 makes the motor 7 in the overload state during the dehydration operation. The number of rotations of the motor 7 decreases.

With this configuration, by adjusting the number of rotations of the motor 7 during the dehydration operation in which the motor current increases as the number of rotations increases, it is possible to effectively suppress an excessive increase in the temperature of the motor winding. (Other embodiments)

As described above, as an example of the technique disclosed in this application, the first embodiment and the second embodiment have been described. However, the technology in this disclosure is not limited to this.

Therefore, other embodiments are exemplified below.

In the first embodiment and the second embodiment, as an example of a washing machine, a rotary tub type washing machine has been described. However, the washing machine only needs to be a washing machine in which a rotating tank is rotated by a motor. Therefore, the washing machine is not limited to a drum-type washing machine, and may be a vertical washing machine or a two-tank washing machine.

In the first embodiment and the second embodiment, an IGBT has been described as an example of a power switching semiconductor. The power switching semiconductor can also be composed of a metal oxide semiconductor field effect transistor (MOSFET) or the like.

In the first embodiment and the second embodiment, the shunt resistance has been described as an example of the current detection unit. However, the current detection unit may also use a method of measuring a DC current transformer or an AC current transformer from a low frequency including a DC current. In addition, in the case of a three-phase motor, the following method can also be used: obtain the two-phase current, and obtain the remaining one phase according to Kirchhoff's circuit law (Iu+Iv+Iw=0).

In the first embodiment and the second embodiment, as an example of the rotor position detection unit, the rotor position detection unit 30 that detects the position of the rotor based on the output reference signals H1 to H3 of the Hall IC is explained. However, the rotor position detection unit is not limited to a member using Hall IC. The rotor position detection unit can also detect the rotor position from the phase current of the motor and the three-phase motor drive control voltage by calculation.

In the first embodiment and the second embodiment, the arithmetic processing in the microcomputer has been described as an example of the low-pass filter unit, but it is not limited to this. As the low-pass filter unit, resistors and capacitors can also be used, and a low-pass filter structure can be implemented on the circuit. In addition, in the first and second embodiments, as an example of low-pass filter processing, the calculation of the amount of change between the previous motor current value and the current value of the motor current is described, and the amount of change is reduced by a fixed ratio and compared with the previous The composition of the sum of the currents of the second detection. However, the low-pass filtering process is not limited to this method. For example, a simple moving average can also be used.

In the first embodiment and the second embodiment, as an example of the low-pass filter processing, the low-pass filter processing (S102) implemented as a loop of the overload state detection processing has been described. The timing of implementing the low-pass filter processing is not limited to step 102, and it may be implemented independently of the overload state detection processing.

In the first embodiment and the second embodiment, as a reference value for determining the non-motor overload state, the threshold value β, which is one-third of the threshold value α, has been described. However, the reference value is not limited to one third of the threshold value α as long as it can determine the non-motor overload state.

In the first embodiment, as an example of the control of the rotational drive of the motor in the motor overload state, an example in which the drive of the motor 7 is stopped in the motor overload state has been described. However, the control of the rotational drive of the motor in the motor overload state is not limited to the stop of the drive. For example, it is also possible to change the stirring time limit during washing, and set the time in the ON state to be short and the time in the OFF state to be long.

In the first embodiment, as a method of controlling the rotational drive of the motor based on the determination result of the overload detection unit, an example in which the drive of the motor 7 is stopped in the motor overload state has been described. However, the method of controlling the rotational drive of the motor is not limited to the stop of the drive of the motor 7 in the motor overload state, and may be the stop of the washing operation. For example, when it is determined that the number of times of the motor overload state exceeds a predetermined number of times, it may be determined that the motor 7 is abnormal. When it is determined that the motor 7 is abnormal, the washing operation may be stopped and an abnormality report may be performed.

The present disclosure can be applied to a device in which a rotating groove is rotated and driven by a motor. Specifically, the present disclosure can be applied to vertical washing machines, drum washing machines, two-tank washing machines, and the like.

1: Washing machine body 2: sink 3: Rotating slot 4: Clothing entrance and exit 5: Door 6: Water hole 7: Motor 7a, 7b, 7c: winding 8: Water injection pipeline 9: Drainage line 10: Operation display panel 12: Supply fan 14: Pulley 15: Fluid balancer 16: belt 17: Rotation center axis 20: Mains 21: Rectifier 22: choke coil 23: Smoothing capacitor 24: converter circuit 24a, 24b, 24c, 24d, 24e, 24f: power switching semiconductors 25: Input setting section 26: Load drive unit 27: Water supply valve 28: Drain valve 29: heat pump 30: Rotor position detection unit 30a, 30b, 30c: Hall IC 31: Control Department 32: drive circuit 33: Low-pass filter processing section 34: Overload detection department 100: washing machine A, B, C, D: motor current S101~S107, S201~S205, S301~S309: steps t1: scheduled time α, β: threshold

Fig. 1 is a longitudinal sectional view showing a schematic configuration of a washing machine in the first embodiment.

Fig. 2 is a block diagram showing the circuit configuration of the washing machine in the first embodiment.

Fig. 3 is a characteristic diagram of motor winding temperature in each current value of the motor of the washing machine in the first embodiment.

Fig. 4 is a flowchart of the overload state detection process of the motor of the washing machine in the first embodiment.

Fig. 5 is a flowchart showing the commutation control process of the motor of the washing machine in the first embodiment.

Fig. 6 is a diagram showing the relationship between the motor current (after low-pass filter processing) and the motor drive command of the washing machine in the first embodiment.

Fig. 7 is a flowchart showing the commutation control process of the motor of the washing machine in the second embodiment.

7: Motor

7a, 7b, 7c: winding

12: Supply fan

20: Mains

21: Rectifier

22: choke coil

23: Smoothing capacitor

24: converter circuit

24a, 24b, 24c, 24d, 24e, 24f: power switching semiconductors

25: Input setting section

26: Load drive unit

27: Water supply valve

28: Drain valve

29: heat pump

30a, 30b, 30c: Hall IC

31: Control Department

32: drive circuit

33: Low-pass filter processing section

34: Overload detection department

Claims (3)

A washing machine with: Rotating slot The motor drives the aforementioned rotating slot to rotate; The commutation circuit converts direct current into alternating current and drives the aforementioned motor; The current detection unit detects the current flowing in the aforementioned motor; The low-pass filter unit performs low-pass filter processing on the current detected by the aforementioned current detection unit, and outputs the processed value of the low-pass filter as the processed current value; The overload detection unit detects the overload status of the aforementioned motor; and The control unit sends a motor drive command to the inverter circuit, and controls the motor through the inverter circuit, The overload detection unit determines that the motor is in an overload state based on the processed current value output by the low-pass filter unit. The control unit controls the rotation drive of the motor based on the determination result of the overload detection unit. Such as the washing machine of claim 1, wherein the overload detection unit determines that the motor is in an overload state when the current value after the processing is greater than or equal to the first value and a predetermined time has elapsed, And when the current value after the aforementioned processing is a second value smaller than the aforementioned first value, the aforementioned overload state is released. The washing machine of claim 1 or 2, wherein the control unit reduces the number of rotations of the motor when the motor is in an overload state during the spin-drying operation.

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