KR100747590B1 - Control circuit and method for sensing abnormal condition of the clothes drier - Google Patents

Abstract

A control circuit of drier and a method for sensing abnormal condition of drier are provided to determine abnormal condition and dry condition by using contacting times to clothes. A control circuit of drier includes a motor, a heater, a detecting circuit, and a micro computer(60). The motor supplies a drum and a blowing fan with power. The heater heats outer air to supply a washing machine with high temperature and dry air. The detecting circuit outputs pulse signals whether dry subject is contacted or not. The micro computer controls driving of the motor and the heater by detecting abnormality of a system whether the detecting circuit outputs the pulse signals or not. The detecting circuit includes an electrode sensor(30), a comparator(40), and a photo coupler(50). The electrode sensor outputs a voltage signal corresponding to impedance generated during the contact with a target subject. The comparator outputs a comparison result by comparing the voltage signal output from the electrode sensor with a predetermined reference voltage. The photo coupler outputs the pulse signals according to the signals output from the comparator.

Description

Control circuit and method for sensing abnormal condition of the clothes drier

1 is a longitudinal sectional view showing a structural example of a general exhaust type clothes dryer

FIG. 2 is a cross-sectional view illustrating main parts of the exhaust clothes dryer of FIG. 1. FIG.

3 shows a control circuit of a dryer according to the present invention.

4 is a graph showing the number of contact with the drying object over time

5 is a flow chart showing a abnormal state detection method of the dryer according to the present invention

* Explanation of symbols for main parts of the drawings

30: electrode sensor 40: comparator

50: photo coupler 60: microcomputer

The present invention relates to a clothes dryer, and more particularly, to a control circuit of the dryer for detecting a system abnormality and a method for detecting the abnormal state.

In general, the clothes dryer is a device for automatically drying the wet clothes after washing is completed, the type can be largely divided into an exhaust type dryer and a condensation type dryer.

The configuration of the exhaust type dryer among these clothes dryers is as follows.

1 illustrates a structure of a general exhaust type dryer, and FIG. 2 illustrates a flow path structure of the dryer of FIG. 1.

The conventional clothes dryer includes a main body 1 having a door 2 formed on a front surface thereof, a drum 3 rotatably installed in the main body 1, and a plurality of lifters 4 protruding from an inner circumferential surface thereof. Driving means for imparting rotational force to the drum 3, a heater 5 for heating the sucked external air to a high temperature to generate hot air, and a rear opening of the drum 3 to communicate with the heater 5; The suction duct 7 for guiding the hot air generated by the drum 3 to the inside of the drum 3 and the lint duct 8 for guiding the humid air discharged after drying by communicating with the front opening of the drum 3 to the exhaust duct 15. ) And a blowing fan 13 installed at the rear of the lint duct 8 to generate a blowing force.

The inlet of the lint duct 8 is provided with a filter 14 for filtering foreign matter such as dust and lint from the air discharged from the drum (3).

Driving means for rotating the drum (3); It consists of a motor 10 and a drive belt 12 connected to the drive pulley 11 coupled to the motor 10 and winding the outer circumferential surface of the drum 3, by rotation of the motor 10. When the drive pulley 11 is rotated, the belt 12 wound around the drive pulley 11 is rotated to rotate the drum 3.

On the other hand, the electrode sensor 30 is installed in front of the drum 3 to detect the drying degree of the object to be dried. The electrode sensor 30 is composed of two metal plates side by side to detect the drying degree of the cloth by using the impedance generated at both ends of the electrode according to the moisture content of the drying object when the drying object is in contact with both metal plates at the same time and the voltage signal Will output

That is, the microprocessor (aka, microcomputer) (not shown) that controls the overall system of the dryer receives a voltage signal from the electrode sensor 30 and determines the degree of drying of the drying object based on the voltage level. Control.

However, when the direct contact method using the electrode sensor 30 is used, precise dryness measurement is impossible because the deviation of the impedance value measured by the amount of the drying object, the amount of moisture, and the impedance difference for each type of the drying object itself is large.

In addition, it is easy to measure the degree of dryness due to the large difference in impedance which is changed during the initial drying of moisture. However, as the drying progresses, the difference in the output voltage becomes extremely insignificant. Therefore, a precise sensor and detection circuit must be provided. do.

In addition, when an inverter control scheme is adopted to freely control the speed of the motor 10, the sensing circuit including the electrode sensor 30 uses a common power supply as well as an inverter circuit and a common power supply. It is connected to the ground.

In this case, the inverter circuit is driven by receiving a commercial AC power source, the sensing circuit is connected to a common ground terminal is not separated from the inverter circuit and the power source, the high voltage is applied to the sensing circuit as it is.

That is, when the user opens the door and puts his hand into the drum while the power is not separated, there is a risk of electric shock (shock) through the clothing in contact with the electrode sensor 30 and the electrode sensor 30.

In addition, when the drying operation is performed in a state in which a drying object is not added due to careless use, such a no-load state cannot be detected in the related art, and thus heat generation of the heater is left for a long time.

In addition, there is no separate means for detecting system abnormalities such as motor restraint or belt disconnection. Therefore, if the system abnormality occurs, heat generation of the heater is continued while the drum is stopped. There was a risk of a safety accident.

The present invention is to solve the above problems, an object of the present invention is to improve the drying performance by implementing a system that can be dried more accurately and safely by applying a new dryness detection method.

Another object of the present invention is to implement a safer system by providing a detection means for detecting a system abnormality such as no-load, but the drum stopped.

The present invention for achieving the above object is a motor for providing power of the drum and blowing fan; A heater for heating the outside air to supply a high temperature dry hot air; A sensing circuit generating a voltage signal upon contact of a building object and outputting a pulsed signal according to a result of comparing the voltage signal with a reference voltage; In addition, the microcomputer detects a system abnormality according to whether a pulsed signal is generated in the sensing circuit and controls the driving of the motor and the heater.

Here, the sensing circuit; An electrode sensor for outputting a voltage signal corresponding to the impedance generated when contacting the object to be dried, a comparator for comparing the voltage signal output from the electrode sensor with a preset reference voltage and outputting a comparison result, and outputting from the comparator And a photocoupler for outputting a pulsed signal according to the received signal.

And, the microcomputer is; If the pulsed signal is not output from the sensing circuit for a predetermined time period, the system recognizes the abnormality and selectively stops the driving of the motor and the heater.

The present invention for achieving the above object is to output a pulsed signal by detecting a contact with a motor for providing power of the drum and the blowing fan, a heater for heating the outside air to supply a high temperature dry hot air, and the drying object With a sensing circuit; A pulse monitoring step of monitoring a pulsed signal output from the sensing circuit; An abnormality determining step of determining a system abnormality according to whether a pulsed signal is output from the sensing circuit for a predetermined time; And, if it is determined that the system abnormality in the abnormal determination step, the system protection step of selectively stopping the operation of the motor and heater; provides a method for detecting the abnormal state of the dryer made.

Here, the abnormal determination step and the system protection step; (a) if the pulsed signal is not output from the sensing circuit for the first set time, stopping driving only the heater while maintaining the driving of the motor; and (b) removing the pulse from the sensing circuit after the step (a). Stopping the driving of the motor and the heater if the pulsed signal is not output during the set time; and (c) restarting the motor and the heater when the pulsed signal is output from the sensing circuit after the step (a). Characterized in that made.

In addition, the present invention provides a method for detecting an abnormal condition of a dryer, further comprising an administrative control step of performing a drying stroke using a high temperature dry hot air by driving the motor and the heater when a system abnormality does not occur in the abnormal determination step. do.

At this time, the administrative control step; Counting the number of pulses per unit time output from the sensing circuit while driving the heater and drum; and determining the completion time of drying and ending all strokes when the counted number of pulses per unit time reaches a predetermined target value. Characterized in that consists of.

Therefore, according to the present invention, it is possible to implement a safer and more accurate dryness detection system by providing a dryness detection means of a new method for determining the dryness using the number of contact with the drying object. Furthermore, the product can be protected by detecting abnormal conditions of the system such as no load and drum stop through an algorithm using the number of contact with the object to be dried.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

First, referring to Figure 3 will be described in detail the control circuit of the dryer according to the present invention.

Since the basic configuration of the dryer is similar to that of Fig. 1, the same components are given the same reference numerals as in the prior art.

As shown, the control circuit of the dryer according to the present invention includes a motor 10 for providing power to the drum 3 and the blowing fan 13; A heater 5 for heating outside air to supply high temperature dry hot air; A sensing circuit for outputting a pulsed signal according to whether or not the object to be dried is touched; The microcomputer 60 detects a system abnormality according to whether a pulse is generated in the sensing circuit and controls the driving of the motor 10 and the heater 5.

Here, the sensing circuit of the present invention compares the electrode sensor 30 for outputting a voltage signal corresponding to the impedance generated when contacting the object to be dried and the voltage signal output from the electrode sensor 30 with a predetermined reference voltage And a photocoupler 50 for outputting a pulsed signal according to the signal output from the comparator 40.

According to the connection structure of the sensing circuit, the output terminal of the electrode sensor 30 is connected to the inverting terminal (-) of the comparator 40 and the preset reference voltage is set according to the voltage divider resistors R2 and R3. Is connected to the non-inverting terminal of (+). In addition, an output terminal of the comparator 40 is connected to a light emitting unit (ie, a light emitting diode) of the photocoupler 50, and a light receiving unit (ie, a photo transistor) of the photocoupler 50 is connected to an input port of the microcomputer 60. It is preferred to be connected.

Here, the reference voltage of the comparator 40 is preferably set to be below the voltage level across the electrode when the fully dried carriage is in contact with the electrode sensor (30). That is, even when the fabric contacts the electrode sensor 30, when the fabric is in a completely dry state, a voltage signal of less than the reference voltage is output so that a signal output to the microcomputer 60 is not generated.

The sensing circuit of the present invention configured as described above is implemented to determine the dry state of the dry object by using the contact number of the dry object without using a direct contact method using the electrode sensor 30.

Furthermore, the sensing circuit may use a separate DC power supply 5V and a ground terminal separated from a motor driving circuit such as an inverter by not using a direct contact method using the electrode sensor 30. In addition, the photo coupler 50 is applied to electrically insulate the electrode sensor 30 and the microcomputer 60.

In detail, when the drying object comes into contact with the electrode sensor 30 while the drum 3 rotates, a voltage signal corresponding to impedance generated at both ends of the electrode of the electrode sensor 30 is generated, thereby inverting the comparator 40. Input to terminal (-).

The comparator 40 compares the voltage signal of the electrode sensor 30 with a reference voltage input to the non-inverting terminal (+) and outputs a high signal when a voltage signal equal to or greater than the reference voltage is input.

The light emitting unit of the photocoupler 50 emits light according to the high signal output from the comparator 40, and the phototransistor, which is the light receiving unit, is turned on by the light generated at this time, and a pulsed signal is transmitted to the microcomputer 60.

That is, one pulse signal is generated every time the electrode sensor 30 contacts the drying object once, and even if a contact with the drying object occurs, a pulse signal is not generated when a voltage signal below the reference voltage is output.

The microcomputer 60 counts the number of pulsed signals output through the photo coupler 50 in unit time units (for example, 1 minute) and uses the number of pulses per unit time (pulse number / 1 minute). To determine the dryness of the object to be dried.

4 is a result of counting the number of pulses per unit time according to the type and amount of guns, which is a graph showing the count value of the pulsed signal versus time.

As shown in the drawing, since most fabrics are wet in the initial stage of the stroke, the number of pulses per unit time due to the contact of the fabric is relatively large, and the number of pulses per unit time decreases as the fabric is increased as the stroke progresses.

Since the target dryness varies depending on the type of stroke (Iron, Light, Normal, etc.), find the number of pulses per unit time corresponding to the target dryness by repeating the test for each stroke type, and set the value in the system in advance. That is, when the number of pulses per unit time due to contact with the object to be dried during the stroke reaches a preset value, it is recognized as the time of completion of drying.

For example, if the setting value corresponding to the normal drying mode is set to 0 (zero) in advance, when the number of pulses per unit time during the stroke reaches a value of zero, the target dryness is reached, that is, when the drying is completed. To judge.

On the other hand, if there is no fabric in the drum 3 in the no-load state, there is no fabric contacting the electrode sensor 30 and there is no relative movement between the electrode sensor 30 and the drying object even when the drum 3 is stopped due to a system abnormality. No pulse from the sense circuit occurs.

Accordingly, the no-load state in the drum 3 and the stationary state of the drum 3 due to the restriction of the motor 10 or the disconnection of the driving belt 12 by using the contact or the number of times of contact with the object to be dried through the sensing circuit. Can be detected.

In the present invention having the above-described detection circuit, a drying method and an abnormal state detection method and a stroke control method of the dryer according to the present invention will be described in detail with reference to FIG. 5 as follows.

When the user inputs a dry start command after putting a dry object into the drum 3 (S10), the motor 10 is operated in the microcomputer 60 to operate the drum 3 and the blowing fan 13. Drive it.

In addition, the heater 5 is driven to heat the outside air sucked by the blower fan 13 by the heater 5, and then forcedly flows into the drum 3 inside the rotary state through the suction duct 7. At this time, the hot air introduced into the drum 3 is dried by evaporating the moisture of the dry object in the wet state, and then discharged to the outside through the lint duct 8 and the exhaust duct 15 as air of low temperature and high humidity.

By this process, a drying administration is performed using a high temperature dry hot air (S20).

While the drying operation is in progress, the microcomputer 60 determines whether there is an output of the pulsed signal from the detection event and counts the number of pulses per unit time when there is an output of the pulsed signal (S30).

In the process of determining whether the pulsed signal is output, the microcomputer 60 determines whether the output of the pulsed signal exists from immediately after the start of the drying operation until the first set time is reached (S40).

As a result of the determination (S40), if there is an output of a pulsed signal, the driving of the heater 5 and the motor 10 is maintained to continue the drying stroke and the counted pulse number per unit time during the drying stroke. It is determined whether or not a predetermined set value which is a criterion of completion of drying is reached (S50).

Thereafter, when the number of pulses per unit time reaches a set value, it is recognized as the completion time of drying and ends all drying operations (S60).

On the other hand, if the output of the pulsed signal does not exist from immediately after the start of the drying operation (S40) until the first set time is reached, the driving of the heater 5 is maintained while the driving of the motor 10 is maintained. It stops (S70).

This means that once the driving of the heater 5 is stopped in order to prevent the temperature rise in the drum 3 when there is no output of the pulsed signal by the first set time (for example, 2 minutes after the start of the stroke). desirable.

Subsequently, it is determined whether there is an output of the pulsed signal from immediately after the start of the drying stroke until the second set time is reached (S80). At this time, even if the pulsed signal is not output until the first set time, if the pulsed signal is detected within the second set time, the driving of the heater 5 and the motor 10 is restarted since the pulsed signal does not correspond to a no load state or a drum stop state. After recovering and entering the step (S50) to perform a dry administration normally (S90).

On the other hand, if the output of the pulsed signal does not exist until the second set time is reached, the driving of the motor 10 as well as the heater 5 is stopped and all the strokes are stopped (S100). At this time, it is preferable to output an error message indicating a system error through the display means of the dryer.

If there is no output of pulsed signal by the second set time (for example, 8 minutes after the start of the stroke), the system is recognized as no-load state or drum stop state and the safety of the system is prevented. It is preferable to stop the first half driving.

As described above, by implementing a new sensing circuit using the number of contact with the dry object rather than the direct contact method using the electrode sensor, it is possible to detect the abnormality of the system and to determine the dry state of the dry object, that is, dryness. You can judge.

The present invention is not limited to the above-described embodiments, and can be modified by those skilled in the art as can be seen from the appended claims, and such modifications are within the scope of the present invention.

The control circuit and the abnormal state detection method of the dryer according to the present invention described above has the following effects.

First, it provides a system that can determine the abnormal state and dryness of the product using the number of contact with the fabric. This enables not only detection of abnormal conditions such as no load but drum stop, but also more accurate drying judgment, which improves product safety and drying performance.

Second, by providing a new system using the number of times of contact with the fabric instead of the direct contact method using the electrode sensor to determine the system abnormality or dryness, it is possible to implement a sensing means that separates the circuit and the power supply requiring high voltage power. . In other words, it is possible to minimize the risk of electric shock to the user and at the same time improve the reliability of the product.

Claims (10)

A motor for providing power to the drum and the blowing fan; A heater for heating the outside air to supply a high temperature dry hot air; A sensing circuit generating a voltage signal upon contact of a building object and outputting a pulsed signal according to a result of comparing the voltage signal with a reference voltage; And, And a microcomputer that detects a system abnormality and controls the driving of the motor and the heater according to whether a pulsed signal is generated in the sensing circuit. The method of claim 1, wherein the sensing circuit; An electrode sensor for outputting a voltage signal corresponding to an impedance generated when the object is contacted with a drying object; A comparator for comparing the voltage signal output from the electrode sensor with a preset reference voltage and outputting a comparison result; And a photocoupler for outputting a pulsed signal according to the signal output from the comparator. The method of claim 2, wherein the sensing circuit; The output terminal of the electrode sensor is connected to the inverting terminal (-) of the comparator and the reference voltage is connected to the non-inverting terminal (+) of the comparator, The output terminal of the comparator is connected to the light emitting unit of the photocoupler and the light receiving unit of the photocoupler is connected to the input port of the microcomputer. The system of claim 1, wherein the system fault is; A control circuit for a dryer, wherein the drum is in a no-load state and a drum stop state due to motor restraint or belt disconnection. The method of claim 1, wherein the micom; And if the pulsed signal is not output from the sensing circuit for a preset time, recognize the system error and selectively stop the driving of the motor and the heater. A motor for providing power to the drum and the blower fan, a heater for heating the outside air to supply high temperature dry hot air, and a sensing circuit for detecting a contact with a drying object and outputting a pulsed signal; A pulse monitoring step of monitoring a pulsed signal output from the sensing circuit; An abnormality determining step of determining a system abnormality according to whether a pulsed signal is output from the sensing circuit for a predetermined time; And, And a system protection step of selectively stopping the driving of the motor and the heater when it is determined that the system is abnormal in the abnormal determination step. The method of claim 6, wherein the abnormal determination step and the system protection step; (a) stopping only driving of the heater while keeping the driving of the motor if the pulsed signal is not output from the sensing circuit during the first set time; and (b) stopping the driving of the motor and the heater when the pulsed signal is not output from the sensing circuit for a second time after the step (a). The method of claim 7, wherein the abnormal determination step and the system protection step; and (c) restarting the motor and the heater when the pulsed signal is output from the sensing circuit after the step (a). The method of claim 6, The abnormal state detection method of the dryer characterized in that it further comprises an administrative control step of performing a drying stroke using a high temperature dry hot air by driving the motor and the heater if the system abnormality does not occur in the abnormal determination step. The method of claim 9, wherein the administrative control step; Counting pulses per unit time output from the sensing circuit while driving the heater and the drum; When the counted pulse number per unit time reaches the target predetermined value is determined by the drying completion time step of the step of detecting the abnormal state of the dryer characterized in that it comprises the step of terminating all the stroke.

Images