KR20100105200A - Washing machine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laundry treatment machine. The laundry treatment machine according to the present invention includes a motor for supplying rotational force to a washing tank, and a plurality of switching elements. And a controller configured to output a switching control signal having a variable pulse width so as to control the switching operation of the inverter by controlling the switching operation of the inverter, and varying a unit period of the switching control signal based on the speed of the motor. This makes it possible to protect the circuit elements in the drive device for driving the motor.

Description

Laundry processing machine {Washing machine}

The present invention relates to a laundry treatment machine, and more particularly, to a laundry treatment apparatus capable of protecting circuit elements in a drive device for driving a motor.

In general, laundry treatment equipment uses chemical reaction between water and detergent and physical action such as friction between water and laundry to separate contaminants on clothes, bedding, etc. (hereinafter referred to as 'laundry'). Say the device. In addition, the wet laundry may be dehydrated and dried, or heated steam may be sprayed onto the laundry. In this way, the laundry treating apparatus is collectively referred to as various apparatuses for applying a physical and chemical effect to the laundry to process the laundry.

On the other hand, the laundry treatment machine is classified into an agitator type, a drum type and a pulsator type according to its structure and washing method.

Such a laundry treatment device, which normally washes laundry while sequentially performing a washing stroke, a rinsing stroke, and a dehydrating stroke, may perform only a predetermined stroke among the above-described strokes according to a user's selection, and according to the type of laundry. Washing is done by a suitable washing method.

On the other hand, the laundry treatment machine uses a motor to transmit the rotational force to the washing tank. The motor rotates at various speeds and transmits the rotational force to the washing tank. The burden of circuit elements in the driving device for driving the motor is increased according to the speed range of the motor. This phenomenon is particularly aggravated in light of the current trend of increasing the size of the washing tank.

An object of the present invention is to provide a laundry treatment apparatus capable of protecting circuit elements in a driving device for driving a motor.

Laundry processing apparatus according to the present invention for achieving the above object is provided with a motor for supplying rotational force to the washing tank, and a plurality of switching elements, by converting a predetermined DC power to an AC power of a predetermined frequency in accordance with the switching operation An inverter for driving the motor and a control unit for outputting a switching control signal of the variable pulse width to control the switching operation of the inverter, the variable period of the switching control signal based on the speed of the motor.

According to the present invention, by varying the unit period of the switching control signal based on the speed of the motor, it is possible to protect the circuit elements, including the inverter in the drive device. In addition, the output current with less current distortion can be supplied to the motor, thereby reducing the noise generated in the motor display.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

1 is a perspective view showing a laundry treatment apparatus according to an embodiment of the present invention, Figure 2 is a side view of the laundry treatment apparatus shown in FIG.

Referring to the drawings, the laundry treatment apparatus 100, the cabinet 110 forming the appearance of the laundry treatment apparatus 100, and the washing tank 120 is disposed inside the cabinet 110 and the laundry is accommodated therein And, the control unit 140 for controlling the overall operation of the laundry processing apparatus 100, and a driving device 150 for supplying a rotational force into the washing tank 120 to rotate the laundry in the washing tank 120.

In addition, the laundry treatment apparatus 100 includes a door 135 rotatably mounted in the cabinet 110 and a detergent box 179 mounted in and out of the cabinet 110 so that laundry can be loaded into and out of the washing tub 120. ), A water supply valve 183 connected to an external water source to regulate a water supply flow path into which the wash water flows, and a drain valve 186 to intercept a drain flow path for discharging the wash water in the washing tank 120 to the outside. .

Some of the washing water introduced from the water supply passage is introduced into the detergent box 179 and mixed with the detergent, and then supplied to the washing tank 120. At this time, the washing water flowing into the detergent box 179 may be interrupted by the auxiliary valve 189.

The washing tub 120 includes an outer tub 128 in which washing water is contained, and an inner tub 125 rotatably disposed in the outer tub 128 to accommodate laundry therein. At this time, the inner tank 125 is formed with a plurality of through-holes (not shown) so that the wash water can circulate between the outer tank 128 and the inner tank (125).

A pulsator 130 may be disposed at the bottom of the inner tank 125 to generate a rotational flow of fresh water. The pulsator 130 is rotated forward and backward by a motor (not shown) in the driving device 150 to supply rotational force into the washing tank 130. The driving device 150 may be controlled by the controller 140. Meanwhile, a clutch (not shown) may be further disposed between the motor (not shown) and the pulsator 130 to transmit rotational force from the motor (not shown). The driving device 150 may further include such a clutch (not shown).

On the other hand, the driving device 150 may rotate the washing tank 120. Specifically, by transmitting the rotational force to the inner tank 125 of the washing tank 12, it may be rotated forward, reverse.

An auto balance (not shown) is provided at an upper portion of the inner tank 125 of the washing tank 120. Auto balance (not shown) is to reduce the vibration caused by the eccentric amount of the laundry contained in the inner tank 125, it may be implemented as a liquid balance, ball balance and the like.

The outer tub 128 of the washing tub 120 may be suspended from the cabinet 110 by the support member 173, and a damper 176 may be provided at one end of the support member 173 to act as a buffer.

On the other hand, the control panel 115 is disposed above the cabinet 110. The control panel 115 is provided with operation keys (not shown) for operating the operation state of the laundry processing apparatus 100 and a display disposed on one side of the operation keys (not shown) to display the operation state of the laundry processing apparatus 100. Device (not shown).

The operation keys (not shown) and the display device (not shown) in the control panel 115 are electrically connected to the control unit 140, and the control unit (not shown) electrically connects each component of the laundry processing apparatus 100, and the like. To control. The operation of the controller (not shown) will be described later.

3 is an internal block diagram of the laundry treatment machine of FIG.

Referring to the drawings, the laundry treatment apparatus of FIG. 3 includes an operation key 117, a display device 118, a washing tub 120, a controller 140, a motor 210, and a position sensing unit 220. It may include.

First, the control unit 140 receives an operation signal from the operation key 117 to operate. Accordingly, main washing, rinsing, and dehydration strokes can be performed.

The controller 140 controls the motor 210 for main washing, rinsing, and dehydration stroke. Although not shown in the figure for motor control, it is possible to be controlled by an inverter (not shown). For example, when the control unit 140 outputs a PWM switching control signal to an inverter (not shown), the inverter (not shown) having a plurality of switching elements performs a high-speed switching operation, and thus, AC power having a predetermined frequency and a predetermined size. This may be supplied to the motor 210. The AC power of the predetermined frequency and the predetermined size at this time may be variously set according to main washing, rinsing, dehydration stroke, and the like. An operation of the inverter (not shown) will be described later with reference to FIG. 4 or below.

In addition, the controller 140 determines the overload or restraint of the motor 210 according to the instantaneously detected dc terminal voltage in the driving device (150 of FIG. 1) to be described later. In order to protect the circuit elements in the driving apparatus 150 of FIG. 1, the rotation speed of the motor 150 is controlled to be lowered. Detailed description thereof will be described later.

On the other hand, the controller 140 may control to display the operation state of the laundry processing apparatus 100 through the display device 118. For example, an operation state such as main washing, rinsing, and dehydration stroke can be displayed.

The motor 210 includes a stator and a rotor, and an alternating current power of each phase is applied to a coil of each stator so that the rotor rotates. The type of the motor 210 may be various forms such as a BLDC motor and a synRM motor.

The motor 210 supplies rotational force to the washing tub 120. As shown in FIG. 1, the motor 210 in the driving device 150 may rotate the pulsator 130. In addition, the washing tank 120, specifically, the inner tank 125 in the washing tank 120 may be rotated. In this way, by rotating the pulsator 130 or by rotating the inner tank 125 in the washing tank 120, thereby providing a rotational force in the washing tank 120.

The position detector 220 detects the position of the motor 210. That is, the position of the rotor of the motor 210 is sensed. The position detecting unit 220 may be various examples such as a hall sensor and an encoder. The position signal H detected through the position sensor 220 is input to the controller 140 for the control operation of the motor 210.

On the other hand, when the Hall sensor is used as the position sensing unit 220, it is also possible to detect the rotor position of each phase of the three-phase motor 210, for example, it is also possible to detect the rotor position of the two phases. The detected two-phase rotor position signals Ha and Hb are input to the controller 140. The position signal H is used herein in the sense including the two-phase rotor position signals Ha, Hb.

4 is an internal block diagram of the driving device of FIG. 1.

Referring to the drawings, the driving device 150 includes a position sensor 220, a converter 410, and an inverter 420. In addition, the driving device 150 of FIG. 4 may further include a reactor L, a smoothing capacitor C, a dc terminal voltage sensing unit A, and the like.

The reactor L is disposed between the commercial AC power supply 405 and the converter 410 to perform power factor correction or step-up operation. In addition, the reactor L may perform a function of limiting harmonic currents due to the fast switching of the converter 410.

The converter 410 converts the commercial AC power 405 into a DC power and outputs the DC power. The commercial AC power 405 input to the converter 410 may be applied via the reactor L as shown in the drawing, but is not limited thereto. Meanwhile, although the commercial AC power supply 405 is illustrated as a single phase AC power in the drawing, it may be a three phase AC power supply.

The converter 410 may include at least one diode element, and may be configured in various forms. For example, it can be configured in various forms, such as a bridge having four diodes. In this case, only the rectifying operation may be performed without the switching operation of the separate switching element.

In addition, the converter 410 may be configured in various forms, including at least one diode and a switching element. For example, a half bridge type converter in which two switching elements and four diodes are connected may be used. In this case, the converter 410 may perform a boost operation, a power factor improvement, and a DC power conversion by a switching operation.

The smoothing capacitor C is connected to the output terminal of the converter 410. The converted DC power output from the converter 410 is smoothed. Hereinafter, the output terminal of the converter 410 is called a dc terminal. The DC voltage smoothed at the dc stage is applied to the inverter 420.

The inverter 420 includes a plurality of inverter switching elements, converts a smoothed DC power source into a three-phase AC power source having a variable frequency and magnitude by on / off operation of the switching element, and outputs the same to the motor 210.

Inverter 420 is a pair of upper arm switching elements Sa, Sb, Sc and lower arm switching elements S'a, S'b, S'c, which are connected in series with each other, and a total of three pairs of upper and lower arms The switching elements are connected in parallel with each other (Sa & S'a, Sb & S'b, Sc & S'c). Diodes are connected in anti-parallel to each of the switching elements Sa, S'a, Sb, S'b, Sc, and S'c.

The switching elements in the inverter 420 perform on / off operations of the respective switching elements based on the inverter switching control signal Sic from the controller 140. By the on / off operation of each switching element, the pulse width of the inverter switching control signal (Sic) is variable, so that the three-phase AC power having a predetermined frequency is output to the motor 210.

On the other hand, the control unit 140 controls the switching operation of the inverter 420. The controller 140 outputs the inverter switching control signal Sic to the inverter 420 in order to control the switching operation of the inverter 420.

The inverter switching control signal Sic is a switching control signal of pulse width modulation (PWM). In the present exemplary embodiment, the unit period of the switching control signal Sic is varied according to the speed of the motor 210. do. A detailed operation of the output of the inverter switching control signal Sic in the controller 140 will be described later with reference to FIG. 5 or below.

The dc terminal voltage detection unit A may instantaneously detect a dc terminal voltage Vdc, which is both ends of the smoothing capacitor C. To this end, the dc terminal voltage sensing unit A may include a resistor or the like. The instantaneous value of the detected dc terminal voltage Vdc may be input to the controller 140 to determine whether the motor 210 operates abnormally.

5 is an internal block diagram of the controller of FIG. 4.

Referring to the drawings, the controller 140 controls the speed calculator 505, the current command generator 510, the voltage command generator 520, and the switching control to output the inverter switching control signal Sic. The signal output unit 530 may be included.

The speed calculator 505 calculates the speed of the motor 210, specifically, the speed of the rotor of the motor 210, based on the position signal H detected by the position sensor 220. The speed of the motor 210 may be an angular speed. The speed of the motor 210 may be calculated as the change amount of the position signal H with respect to the unit time.

The speed calculator 505 may estimate the output current io flowing through the motor 210 based on the position signal H detected by the position detector 220. For example, calculating the speed of the motor 210 based on the position signal H, the output current is derived from the relationship between the mechanical equation based on the speed of the motor 210 and the electrical equation based on the current of the motor 210. (io) can be estimated.

The current command generation unit 510 generates a d, q-axis current command value i ^* d, i ^* q through a PI controller or the like based on the estimated speed v and the speed command value v ^* . In the drawing, although the d, q-axis current command value (i ^* d, i ^* q) is generated by vector control, the present invention is not limited thereto, and the current command value I, which is a scalar value, may be output. .

The voltage command generation unit 520, based on the d, q-axis current command value (i ^* d, i ^* q) and the output current (io) estimated by the speed calculating unit 505, via the PI controller, d, Generate the q-axis voltage command value (v ^* d, v ^* q). In the drawing, although the d, q-axis voltage command value (v ^* d, v ^* q) is generated through vector control, the present invention is not limited thereto, and the voltage command value V, which is a scalar value, may be output.

The switching control signal output unit 530 switches the switching elements Sa, S'a, Sb, S'b, Sc, and S in the inverter 420 based on the d, q-axis voltage command values v ^* d, v ^* q. The inverter switching control signal (Sic) is output to the inverter 420 to drive 'c).

After all, the control unit 140, in accordance with the steps, such as washing cycle, the rinsing cycle and a dehydrating stroke, and according to the amount of laundry and determines the speed command value (v ^*), on the basis of the speed command value (v ^*) is determined And outputs an inverter switching control signal (Sic) having a variable pulse width.

6 is a view showing an example of the operation of the washing machine motor.

Referring to the drawings, the first section Ta is a low speed region in which the speed of the motor 210 is low, and shows that the forward rotation and the reverse rotation are repeated several times. This first section Ta may be at the time of stirring washing or inflated stroke.

Typically, in accordance with the inverter switching control signal Sic of FIGS. 4 and 5, a switching loss occurs when a switching operation of the switching elements in the inverter 420 is performed. This switching loss is particularly severe in a low speed region, such as the first section Ta, where the speed of the motor 210 is low. In addition, this switching loss becomes even more severe when the forward rotation and the reverse rotation are repeated a predetermined number of times.

Accordingly, in the embodiment of the present invention, the control unit 140 varies the unit period (also referred to as clock frequency in other terms) of the switching control signal Sic based on the speed of the motor 210. For example, in a low speed region such as the first section Ta, it is preferable to set the unit period of the switching control signal Sic to be large. Accordingly, the number of switching for a certain time is reduced, thereby reducing the switching loss. Therefore, the temperature rise of the circuit elements in the driving apparatus 150 including the inverter 420 is suppressed, so that the possibility of burnout or the like is significantly lowered.

The second section Tb is a high speed region in which the speed of the motor 210 is high, and may be during a dehydration stroke. In the region where the speed of the motor 210 is high, the pulse width of the switching control signal Sic becomes large. As a result, the output current flowing through the motor becomes large.

Typically, when the output current io flowing through the motor 210 increases, a current distortion phenomenon occurs. In the embodiment of the present invention, in the high speed region such as the second section Tb, the switching control signal Sic Set the unit cycle of) to be smaller. Accordingly, the output current io, through which current distortion is reduced, flows to the motor 210, and therefore, the noise of the motor 210 is significantly reduced. In addition, it is possible to control the motor 210 so that the actual operating speed of the motor 210 quickly follows the speed command value v ^* .

As a result, according to the exemplary embodiment of the present disclosure, the control unit 140 may set the unit period of the switching control signal Sic to increase as the speed of the motor 210 is lower. To this end, the controller 140 may include a lookup table in which different unit periods are set according to the speed of the motor 210.

In addition, the controller 210 may set the unit period of the switching control signal Sic to be large when the motor 210 repeatedly performs the forward rotation and the reverse rotation more than a predetermined number of times.

In addition, the controller 210 may set the unit cycle of the switching control signal Sic to be larger during the washing stroke than during the dehydrating stroke.

Meanwhile, as described above, the speed of the motor 210 may be calculated from the position signal H in the speed calculator 505 of FIG. 5.

7 is a view illustrating varying a period of a switching control signal according to an embodiment of the present invention.

Referring to the drawings, firstly, FIG. 7A illustrates a first switching control signal Sic1 having a first unit period T1 in the region rh, such as the second section Tb of FIG. 6. do. According to the first switching control signal Sic1, the phase voltage Va1 as shown in the drawing may be applied to the motor 210.

Meanwhile, FIG. 7B illustrates the second switching control signal Sic2 having the second unit period T2 in the low speed region such as the first section Ta. According to the second switching control signal Sic2, the phase voltage Va2 as shown in the drawing may be applied to the motor 210.

When the two switching control signals Sic1 and Sic2 are compared, the maximum pulse width Pm1 is the same while the pulse width is variable, but the unit period of the second switching control signal Sic2 is larger (T1 <T2). Able to know. The first unit period T1 may be approximately 50us, and the second unit period T2 may be approximately 60us.

As such, the lower the speed of the motor 210, the greater the unit period of the switching control signal (Sic), thereby reducing the switching loss in the inverter 420, the speed of the motor 210 The higher, the smaller the unit period of the switching control signal (Sic), thereby generating an output current (io) with reduced distortion, so that noise can be reduced when the motor 210 rotates.

On the other hand, the laundry treatment apparatus according to the embodiment of the present invention described above, but described mainly with a vortex-type laundry treatment device having a pulsator, irrespective of this will be applicable to a stirring or drum-type laundry treatment device. That is, it will be sufficient if the washing rod, the drum, the pulsator, etc. are rotated by the driving of the motor so that the rotational force is transmitted to the washing tank.

While the above has been shown and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, it is usually in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a perspective view showing a laundry treatment apparatus according to an embodiment of the present invention.

Figure 2 is a side view of the laundry treatment machine shown in FIG.

3 is an internal block diagram of the laundry treatment machine of FIG.

4 is an internal block diagram of the driving device of FIG. 1.

5 is an internal block diagram of the controller of FIG. 4.

6 is a view showing an example of the operation of the washing machine motor.

7 is a view illustrating varying a period of a switching control signal according to an embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>

100: laundry processing apparatus 110: cabinet

120: washing tank 140: control unit

150: drive device 210: motor

220: position detection unit 410: converter

420: inverter

Claims (8)

A motor for supplying rotational force to the washing tank; An inverter having a plurality of switching elements and converting a predetermined DC power source into an AC power source having a predetermined frequency according to a switching operation to drive the motor; And And a controller configured to output a switching control signal having a variable pulse width so as to control a switching operation of the inverter, and varying a unit cycle of the switching control signal based on the speed of the motor. The method of claim 1, The control unit, The lower the speed of the motor, the laundry treatment device, characterized in that the variable so that the unit cycle of the switching control signal is larger. The method of claim 1, The control unit, The laundry machine according to claim 1, wherein the unit cycle of the switching control signal is varied when the motor repeats the forward rotation and the reverse rotation more than a predetermined number of times. The method of claim 1, The control unit, And a unit cycle of the switching control signal during the washing stroke is larger than during the dehydrating stroke. The method of claim 1, And a converter for converting commercial AC power into DC power. The method of claim 1, Laundry treatment apparatus further comprises a; position detection unit for detecting the position of the motor. The method of claim 6, The control unit, A speed calculator configured to estimate a speed based on the detected position of the motor; A current command generation unit that generates a current command value based on the estimated speed and the speed command value; A voltage command generator that generates a voltage command value based on the current command value; And And a switching control signal output unit configured to generate and output an inverter switching control signal based on the voltage command value. The method of claim 7, wherein The speed calculator, based on the detected position of the motor, estimates the output current of the motor, And the voltage command generator generates the voltage command value based on the estimated output current and the current command value.

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