WASHING MACHINE AND METHOD OF CONTROLLING THE SAME

Abstract

Disclosed herein are a washing machine and a method of controlling the same. The washing machine includes a motor configured to generate a rotational force, an inverter module with a plurality of switching circuits installed therein and configured to adjust a driving current supplied to the motor, and a controller configured to detect whether a fault signal is generated by an overcurrent in the inverter module and to control opening and closing of at least one of the plurality of switching circuits based on a detection result of the occurrence of fault signal when controlling the driving of the motor.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

The present application is related to and claims the benefit of Korean Patent Application No. 10-2016-0058272, filed on May 12, 2016 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

Field of the Invention

Embodiments of the present disclosure relate to a washing machine having an inverter module, and a method of controlling the same.

Discussion of Related Art

A variety of home appliances such as washing machines, air conditioners, and refrigerators have been widely used in homes, thereby increasing convenience for users. Particularly, as research on miniaturization of home appliances continues, home appliances including an inverter module capable of efficiently controlling power supply are increasing in popularity.

However, if the inverter module breaks, various accidents threatening the safety of the user such as fire and water leakage may occur as well as causing replacement of parts. Accordingly, various studies are underway to prevent the inverter module from breaking and the above-mentioned accidents.

SUMMARY

To address the above-discussed deficiencies, it is a primary object to provide a washing machine of preventing breakdown of an inverter module and controlling power supply more efficiently.

In accordance with one aspect of the present disclosure, a washing machine comprises a motor configured to generate a rotational force, an inverter module with a plurality of switching circuits installed therein and configured to adjust a driving current supplied to the motor, and a controller configured to detect whether a fault signal is generated by an overcurrent in the inverter module and to control opening and closing of at least one of the plurality of switching circuits based on a detection result of the occurrence of fault signal when controlling the driving of the motor.

Also, wherein when stopping the motor, the controller controls opening and closing of at least one of the plurality of switching circuits based on at least one of the detection result of the occurrence of the fault signal and a detection result of a number of occurrences of the fault signal.

Also, wherein the plurality of switching circuits comprises at least one upper switching circuit and at least one lower switching circuit.

Also, wherein when controlling driving of the motor, the controller performs a short brake operation by controlling some of the plurality of lower switching circuits to be shorted and other lower switching circuits to be opened when the fault signal is detected.

Also, wherein the controller performs a short brake operation by controlling opening and closing of at least one of the lower switching circuits when a second fault signal is detected within a predetermined time after detection of a first fault signal.

Also, wherein when controlling driving of the motor, the controller controls at least one of the plurality of lower switching circuits to be shorted to generate a closed loop comprising at least one of a plurality of input terminals connected to the motor to supply a driving current when the fault signal is detected.

Also, wherein the controller changes opening and closing of at least one of the plurality of lower switching circuits to perform a short brake operation through another closed loop different from the closed loop when a second fault signal is detected within a predetermined time after detection of a first fault signal.

Also, wherein the controller performs an open brake operation by controlling at least one of the plurality of switching circuits when the fault signal is detected more than a predetermined number of times.

Also, wherein the controller controls opening and closing of at least one of the lower switching circuits to determine whether at least one of the upper switching circuits is broken.

In accordance with one aspect of the present disclosure, a method of controlling a washing machine comprises controlling driving a motor in accordance with an operation mode; detecting a fault signal generated by an overcurrent in an inverter module when controlling driving of the motor, and controlling a plurality of switching circuits comprised in the inverter module based on a detection result of the fault signal.

Also, wherein the controlling of a plurality of switching circuits is performed by controlling the plurality of switching circuits based on at least one of the detection result of the occurrence of the fault signal and a detection result of a number of occurrences of the fault signal.

Also, wherein the controlling of a plurality of switching circuits further comprises performing a short brake operation by controlling some of a plurality of lower switching circuits to be shorted and other lower switching circuits to be opened when the fault signal is detected.

Also, wherein the controlling of a plurality of switching circuits further comprises performing a short brake operation by controlling at least one of the lower switching circuits when a second fault signal is detected within a predetermined time after detection of a first fault signal.

Also, wherein the controlling of a plurality of switching circuits further comprises performing a short brake operation by controlling at least one of the plurality of lower switching circuits to be shorted to generate a closed loop comprising at least one of a plurality of input terminals connected to the motor to supply a driving current when the fault signal is detected.

Also, wherein the controlling of a plurality of switching circuits further comprises controlling opening and closing of at least one of the plurality of lower switching circuits to perform a short brake operation through another closed loop different from the closed loop when a second fault signal is detected within a predetermined time after detection of a first fault signal.

Also, wherein the controlling of a plurality of switching circuits further comprises performing an open brake operation by controlling at least one of the plurality of switching circuits when the fault signal is detected more than a predetermined number of times.

Also, wherein the plurality of switching circuits comprises at least one upper switching circuit and at least one lower switching circuit, and the controlling of a plurality of switching circuits further comprises determining whether the at least one upper switching circuit is broken by controlling opening and closing of the at least one lower switching circuit.

As described above, it is possible to more effectively control the inverter module according to whether a fault signal is detected, thereby preventing breakage of an inverter module and driving the motor more efficiently.

Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

FIG. 1 is a schematic cross-sectional view of a washing machine according to an embodiment;

FIG. 2 is an exploded view of a driving device of a washing machine according to an embodiment;

FIG. 3 is a control block diagram of a washing machine according to an embodiment;

FIGS. 4 and 5 are control block diagrams of the washing machine, illustrating internal structures of an inverter module according to an embodiment in more detail;

FIGS. 6A and 6B are views for describing a method of stopping a motor by controlling opening and closing of a plurality of switching circuits according to different embodiments;

FIGS. 7, 8 and 9 are views for describing methods of stopping a motor by changing a closed loop by controlling opening and closing of switching circuits according to different embodiments;

FIG. 10 is a flowchart for describing a method of controlling a switching circuit based on a number of times of detection of a fault signal in stopping a three-phase motor according to an embodiment; and

FIG. 11 is a flowchart for describing operation of a washing machine according to an embodiment.

DETAILED DESCRIPTION

FIGS. 1 through 11, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged device.

Embodiments and features as described and illustrated in the present disclosure are only preferred examples, and various modifications thereof may also fall within the scope of the disclosure.

Meanwhile, a method for preventing the inverter module from being broken due to overcurrent or overvoltage described below may be applied to various home appliances. For example, the method described below may be applied to any home appliance having an inverter module that receives power and regulates a current supplied to an internal component. Therefore, although a washing machine will be described as an example of a home appliance in the following description, the embodiments to be described later are not limited thereto and may be applied to all home appliances.

Generally, a washing machine is a device including a tub to retain water (washing water or rinsing water), a washing tub which is rotatably installed inside the tub and accommodates laundry, a pulsator rotatably installed in the washing tub to generate water streams, and a motor to generate a driving force to rotate the washing tub and the pulsator, and removing contaminants from the laundry by the water streams and interfacial action of a detergent. Hereinafter, a structure of the washing machine will be described in more detail.

FIG. 1 is a schematic cross-sectional view of a washing machine according to an embodiment.

In the meantime, the embodiment of the washing machine is not limited to a top-loading washing machine of FIG. 1 in which the laundry is accommodated in the washing tub, the pulsator generating water streams on the bottom of the washing tub is provided, and the laundry is washed using the water streams generated by the pulsator. Alternatively, it is possible to use a front-loading type in which washing is performed using a drop of the laundry while the washing tub containing the laundry is rotating.

Referring to FIG. 1, a washing machine 1 includes a cabinet 20 forming an outer appearance, a tub 30 disposed inside the cabinet 20 to store water, a tub 30 rotatably disposed inside the tub 30, a pulsator 45 disposed inside the washing tub 40 to generate water streams and a driving device 10 to rotate the washing tub 40 or the pulsator 45.

An inlet 22 to introduce laundry into the washing tub 40 is formed in an upper portion of the cabinet 20 and the inlet 22 is opened and closed by a door 21 installed at an upper portion of the cabinet 20.

The tub 30 may be supported in a state of being hung on the cabinet 20 by a suspension device 31 connecting the lower side of the outer surface of the tub 30 and the upper side of the cabinet 20. The suspension device 31 may attenuate vibrations generated in the tub 30 during washing or spin-drying.

A water supply pipe 51 for supplying water to the tub 30 is installed at an upper portion of the tub 30. One end of the water supply pipe 51 is connected to an external water supply source, and the other end of the water supply pipe 51 is connected to a detergent supply device 50. Water supplied through the water supply pipe 51 may be supplied into the tub 30 together with the detergent via the detergent supply device 50. A water supply valve 52 installed in the water supply pipe 51 may control the supply of water.

The washing tub 40 is formed into a cylindrical shape with an open top, and laundry is accommodated therein. A plurality of dewatering holes 41 are provided in the side surface of the washing tub 40 and the plurality of dewatering holes 41 communicate the inner space of the tub 40 and the inner space of the tub 30.

A balancer 42 is mounted on the upper portion of the washing tub 40. The balancer 42 may guide the washing tub 40 to rotate stably by canceling an unbalanced load generated in the washing tub 40 when the washing tub 40 rotates at a high speed.

The pulsator 45 rotates in a forward direction or a reverse direction to generate water streams, and the laundry in the washing tub 40 may be stirred together with water by the generated water streams.

A drain port 60 is formed at the bottom of the tub 30 and the drain port 60 has a space for draining water stored in the tub 30. A first drain pipe 61 is connected to the drain hole 60. Further, the first drain pipe 61 is provided with a drain valve 62, and the drain valve 62 may control drainage of water.

A second drain pipe 63 is connected to an outlet of the drain valve 62, and the second drain pipe 63 may provide space for water to be discharged to the outside. The drain valve 62 may be a solenoid device or a link device connected to an electric drive motor. In addition to the drain valve 62, various devices may be used to draining water inside the tub 30 to the outside.

The driving device 10 is provided below the tub 30 and selectively provides a rotational force to the washing tub 40 or the pulsator 45. Specifically, the driving device 10 provides a forward or reverse rotational force to the pulsator 45 during the washing and rinsing cycles, and provides the reverse rotational force to the washing tub 40 and the pulsator 45 during the spin-drying cycle. Hereinafter, the inside of the driving device 10 will be described in more detail.

FIG. 2 is an exploded view of a driving device of a washing machine according to an embodiment.

The driving device 10 includes a motor 100 that generates a rotational force by receiving power, a driving shaft 70 that transmits the rotational force generated by the motor 100 to the washing tub 40 and the pulsator 45, and a clutch 200 that controls rotation of the driving shaft 70 to simultaneously or selectively rotate the pulsator 45 and the washing tub 40.

The driving shaft 70 may include a spin-drying shaft 72 to transmit a rotational force to the washing tub 40 and a washing shaft 71 to rotate the pulsator 45. At this time, a hollow is formed in the spin-drying shaft 72 and the washing shaft 71 and a rotary shaft 221 of the clutch 200 are positioned inside the hollow of the spin-drying shaft 72.

The clutch 200 includes a clutch body 210 that forms an outer appearance and a switching gear assembly 220 that is disposed below the clutch body 210 and selectively transmits the rotational force of the rotary shaft 221 coupled to a rotor 120 of the motor 100 to the washing shaft 71 and the spin-drying shaft 72 depending on the operation of the washing machine, and a brake assembly 230 to brake the rotation of the washing tub 40.

Meanwhile, the rotary shaft 221 may be connected to the motor 100. Here, various well-known motors that receive power and generate the rotational force may be used as the motor 100 installed in the washing machine 1. In the following description, a three-phase brushless direct current (three-phase BLDC) motor will be described as the motor 100. However, the following embodiments are not limited to the three-phase brushless direct current motor, any other known motors well known in the art which receive power and generate a rotational force may be applied.

Referring to FIG. 2, the motor 100 includes a stator 110 fixed to the clutch 200 and a rotor 120 disposed to surround the stator 110 and rotating with electromagnetic interaction with the stator 110.

The stator 110 includes a base 111 of an annular shape, a plurality of teeth 112 disposed along the outer periphery of the base 111 and protruding outward with respect to the radial direction of the stator 110, and coils 113 wound respectively around the teeth 112. The coils 113 may generate a magnetic field by current flowing in the coil 113, and the plurality of teeth 112 may be magnetized by the generated magnetic field.

On the upper side of the base 111, a mounting surface 114 is formed in an annular shape. On the other hand, when the stator 110 is engaged with the clutch 200, the clutch 200 may be seated on the mounting surface 114. An opening 115 is formed inside the base 111 and the mounting surface 114. When the clutch 200 and the stator 110 are coupled to each other, the switching gear assembly 220 and the lower protruding portion 215 may be disposed inside the stator 110 through the opening 115.

The rotor 120 has a bottom surface 121 and side walls 122 projecting from the rim of the bottom surface 121. A plurality of permanent magnets 123 are coupled to the inner surface of the side wall 122 to magnetically interact with the coils 113 of the stator 110 to rotate the rotor 120.

A coupling hole 125 is formed in a center of the rotor 120 so that the coupling between the rotary shaft 221 of the clutch 200 and the rotor 120 may be achieved by inserting the coupling member. The rotary shaft 221 coupled to the rotor 120 is connected to the washing shaft 71 from the deceleration brake assembly 230 through the hollow of the spin-drying shaft 72. The washing shaft 71 passes through the hollow of the spin-drying shaft 72 and is coupled to the pulsator 45.

On the other hand, in order for the motor 100 to generate a rotational force, a driving current needs to be supplied. An inverter module is installed in the washing machine 1 according to an embodiment, the supply of a driving current may be controlled by the inverter module. Hereinafter, a control block diagram of the washing machine 1 including an inverter module to control a driving current supplied to the motor 100 will be described in more detail.

FIG. 3 is a control block diagram of a washing machine according to an embodiment. FIGS. 4 and 5 are control block diagrams of the washing machine illustrating internal structures of an inverter module according to an embodiment in more detail. FIGS. 6A and 6B are views for describing a method of stopping a motor by controlling opening and closing of a plurality of switching circuits according to different embodiments. Hereinafter, the drawings will be synthetically described to avoid repeated descriptions.

Referring to FIG. 3, a washing machine 1 includes a rectifier 500 configured to commutate supplied power, a motor 100 configured to generate a rotational force upon receiving a driving current, an inverter module 400 configured to control the commutated power to be supplied to the motor 100, and a driving current sensor 430 configured to sense the driving current supplied to the motor 100, a hall sensor 600 configured to sense a rotational displacement of the rotor 120 as shown in FIG. 2, and a controller 300 configured to control the overall operation of the washing machine 1. The detailed description of the motor 100 has been described above and will be omitted.

The inverter module 400 connects the rectifier 500 and the motor 100. The inverter module 400 includes an inverter circuit 410 including a plurality of switching circuits to control the supply of the driving current by opening and closing the plurality of switching circuits, and an inverter controller 420 configured to control the overall operation of the inverter module 400. For example, the inverter module 400 may be an intelligent power module (IPM), but is not limited thereto.

The inverter circuit 410 may include the plurality of switching circuits. Referring to FIG. 4, the inverter circuit 410 may include three upper switching circuits Q11 to Q13 and lower switching circuits Q21 to Q23.

The upper switching circuits Q11 to Q13 and the lower switching circuits Q21 to Q23 may be implemented using various devices. For example, the upper switching circuits Q11 to Q13 and the lower switching circuits Q21 to Q23 may be implemented using a high voltage bipolar junction transistor, a high voltage field effect transistor, or an insulated gate bipolar transistor (IGBT), and a free wheeling diode.

The three upper switching circuits Q11 to Q13 and the three lower switching circuits Q21 to Q23 may be connected in series, respectively. Referring to FIG. 4, a first upper switching circuit Q11 is connected in series with a first lower switching circuit Q21 on a U stage, a second upper switching circuit Q12 is connected in series with a second lower switching circuit Q22 on a V stage, and a third upper switching circuit Q13 may be connected in series with a third lower switching circuit Q23 on a W stage. Referring to FIG. 4, a diode D may be connected in parallel with the U stage, the V stage, and the W stage

Three nodes to which the three upper switching circuits Q11 to Q13 and the three lower switching circuits Q21 to Q23 are respectively connected are connected to three input terminals a, b, and c of the motor 100, respectively. Thus, the driving current may be supplied to the motor 100 through the three input terminals a, b, and c.

Meanwhile, the inverter module 400 may include the inverter controller 420. Here, the inverter controller 420 may be realized using various arithmetic processing devices capable of performing arithmetic processing such as a processor or a micro control unit (MCU). In addition, although FIG. 4 shows the inverter controller 420 separately provided, the embodiment is not limited thereto. The controller 300 may also include the inverter controller 420.

The inverter controller 420 may control opening and closing, i.e., On and Off operation, of the upper switching circuits Q11 to Q13 and the lower switching circuits Q21 to Q23 to control the driving current supplied to the motor 100. For example, the inverter controller 420 receives a control signal from the controller 300 and may control turning on/off the upper switching circuits Q11 to Q13 and the lower switching circuits Q21 to Q23.

Also, the inverter controller 420 may measure a current value on a resistor R connected to an N-th stage and output a fault signal when the measured current value exceeds a predetermined value. For example, the inverter controller 420 may output a fault signal to the controller 300. Here, the fault signal refers to a signal output when there is a possibility of a breakdown of the inverter module 400 due to an overcurrent. In one embodiment, the fault signal may be output when the current value on the resistor R connected to the N-th stage is about 20 A at about 15 A, without being limited thereto.

The washing machine 1 may include a driving current sensor 430 for sensing a driving current value supplied to the motor 100. Referring to FIG. 4, the driving current sensor 430 may sense driving current values on three input terminals a, b, and c connected to the motor 100. For example, the driving current sensor 430 may include sensing resistors to sense driving current values. In this regard, shunt resistors may be used as the resistors. However, the embodiment is not limited thereto and any other various known resistors may also be used.

In one embodiment, the driving current sensor 430 may detect voltage drops of the shunt resistors respectively connected in series to the three input terminals a, b, and c connected to the motor 100 and sense driving current values using the detected voltage drops. That is, the driving current sensor 430 may measure the driving current values of the shunt resistors respectively connected in series to the three input terminals a, b, and c connected to the motor 100. Accordingly, the controller 300 may control the motor 100 by comparing a supplied actual current value with a command current value.

The sensing resistor is not limited to being connected in series to each of the three input terminals a, b, and c connected to the motor 100 as shown in FIG. 4. For example, referring to FIG. 5, the driving current sensor 430 may measure current values through shunt resistors connected in series to bottoms of the lower switching circuits Q21, Q22, and Q23, and transmit measurement results to a controller 300, without being limited thereto.

Also, the washing machine 1 may include a hall sensor 600 for sensing a rotational displacement of the rotor 120 as shown in FIG. 2. For example, the hall sensor 600 may be connected to one side of the upper surface of the stator 110 as shown in FIG. 2. Accordingly, the hall sensor 600 may sense a change in a magnetic field due to rotation of the permanent magnet 123 as shown in FIG. 2 attached to the rotor 120, thereby outputting the angle, frequency, etc. related to the rotational displacement of the rotor 120.

As the hall sensor 600, various angle sensors may be used. For example, as the hall sensor 600, an angle sensor such as a potentiometer, an absolute encoder, or an incremental encoder may be used. Here, a potentiometer refers to an angle sensor to calculate an electrical input proportional to a rotating angle by varying a value of a variable resistor according to the angle. In addition, the absolute encoder refers to an angle sensor to detect a position of an optical pulse wave by using a certain degree of rotation without setting a reference position.

The incremental encoder refers to an angle sensor to detect a certain degree of rotation using an optical pulse wave by calculating an angle by increasing or decreasing a measured angle by setting a reference position. In addition, various types of angle sensors for measuring an angle and a frequency may be used as the hall sensor 600, but the embodiment is not limited to the above-mentioned examples.

Meanwhile, the washing machine 1 may include a controller 300. The controller 300 may be implemented by a processor or an arithmetic processing unit capable of performing various arithmetic operations such as an MCU. The controller 300 may control the overall operation of the washing machine 1. The controller 300 may generate a control signal and control operation of components of the washing machine 1 through the generated control signal.

For example, when an operation command is input from a user through an input/output (I/O) interface device provided in the washing machine 1, the controller 300 controls the operation of components of the washing machine 1 using a control signal, so that the operation desired by the user is performed. In one embodiment, the controller 300 may control the operation of the washing machine 1 according to an operation command input by the user via the I/O interface device, and programs and data stored in a memory.

For example, the controller 300 may perform at least one of water supply operation, washing operation, and spin-drying operation, and the like as a part of a washing cycle. Referring to FIGS.1 to 3, during the water supply operation, the controller 300 may open the water supply valve 52 by a control signal so that water is supplied to the washing tub 40 (FIG. 1) and control the inverter module 400 to supply the driving current to the motor 100 so that the pulsator 45 (FIG. 1) rotates.

The controller 300 may control the inverter module 400 to supply a driving current to the motor 100 to generate a rotational force to perform a washing operation. In addition, when the washing operation is completed, the controller 300 may stop the motor 100. Also, when a stop command is input from a user during the washing operation, the controller 300 may control the inverter module 400 to stop the motor 100. Also, when a spin-drying operation is completed, the controller 300 may control the inverter module 400 to stop the motor 100.

In other words, the controller 300 may control the inverter module 400 to operate or stop the motor 100 according to an input operation command, the operation mode, or the like. At this time, the controller 300 may stop the motor 100 in various ways according to a driving state of the motor 100.

For example, if a revolution per minute (RPM) of the motor 100 is high, i.e., if a rotation speed of the motor 100 is high, the controller 300 may perform deceleration control operation and a short brake operation to stop the motor 100. Further, if the rotation speed of the motor 100 is low, the controller 300 may perform an open brake operation.

In one embodiment, when the motor 100 is stopped after a washing operation is completed, the controller 300 may stop the motor 100 by performing at least one of the deceleration control operation and the short brake operation. In another embodiment, when the motor 100 is stopped after a spin-drying operation is completed, the controller 300 may stop the motor 100 by performing at least one of the open brake operation and the short brake operation.

At this time, data on methods of stopping the motor 100 according to driving states and operation statuses of the motor 100 may be pre-stored in a memory of the washing machine 1, and the controller 300 may control the motor 100 using the data pre-stored in the memory. Hereinafter, a driving method for stopping the motor 100 will be described in more detail.

FIGS. 6A and 6B are views for describing a method of controlling opening and closing of a plurality of switching circuits to stop a motor according to different embodiments. Hereinafter, the rectifier 500 and the six switching circuits Q11 to Q13 and Q21 to Q23 are briefly shown in FIGS. 6A and 6B for convenience of explanation.

The controller 300 may perform stop the motor 100 through various methods according to the driving states of the motor 100 as described above. For example, the controller 300 may stop the motor by a general deceleration control operation including receiving a driving current supplied to the motor 100 and measured by the driving current sensor 430 as described above, and driving a speed of the motor 100 based on a comparison result between the driving current and a command current.

As another example, the controller 300 may perform a short brake operation to turn on or short the three lower switching circuits Q21 to Q23 among the six switching circuits Q11 to Q13 and Q21 to Q23 in the inverter module 400 as shown in FIG. 6A. The short brake operation refers to operation of disconnecting the motor 100 from the rectifier 500 by shorting all of the lower switching circuits Q21 to Q23 to construct a closed loop C1 including at least one of the input terminals a, b, and c of the motor 100.

When the short brake operation is performed, the connection between the motor 100 and the rectifier 500 is cut off, so that a power supply to the motor 100 is stopped. Three-phase residual power eas, ebs, and ecs of the motor 100 may be consumed through the impedances Z1, Z2, and Z3 connected to the input terminals a, b, and c, respectively.

As another example, the controller 300 may perform an open brake operation to turn off all of the six switching circuits Q11 to Q13 and Q21 to Q23 in the inverter module 400 as shown in FIG. 6B. In this case, three-phase residual power eas, ebs, and ecs of the motor 100 is not consumed through the impedances Z1, Z2, Z3 connected to the input terminals a, b, so that he motor 100 may stop more slowly than by the short brake operation.

That is, when the short brake operation is performed, the motor 100 may be stopped more quickly than when the open brake operation is performed. However, if at least one of the three upper switching circuits Q11 to Q13 is shorted due to breakage and short brake operation is performed, an arm short is caused.

The arm short refers to when a plurality of switching elements at a same stage are shorted simultaneously. For example, the arm short may occur when the first upper switching circuit Q11 and the first lower switching circuit Q21 connected on the same U stage are shorted. Also, the arm short may occur when the second upper switching circuit Q12 and the second lower switching circuit Q22 connected on the V stage are shorted. Also, the arm short may occur when the third upper switching circuit Q13 and the third lower switching circuit Q23 connected on the W stage are shorted.

When the arm short occurs, an overcurrent is generated due to the DC power rectified by the rectifier 500, so that not only the inverter module 400 may be damaged, but various accidents affecting safety of users such as fire and water leakage may occur.

Referring to FIG. 4 and FIG. 5, the resistor R may be connected to the N-th stage. The inverter controller 420 may detect a current value on the resistor R. When the detected current value reaches a preset value, the inverter controller 420 may output a fault signal to the controller 300.

At this time, a conventional washing machine performs a protection process for protecting an inverter module itself. For example, if at least one of the upper switching circuits is shorted due to breakage and a fault signal is detected due to generation of an arm short, the conventional washing machine performs reset, i.e., initialization, for protection of the inverter module. As a specific example, the conventional washing machine performs an open brake operation to open all six switching circuits included in the inverter module. When a predetermined time has elapsed after the open brake operation is performed, the conventional washing machine performs a short brake operation after determining that the conventional washing machine has been switched to the normal state.

At this time, since at least one of the upper switching circuits is still broken, the arm short circuit is generated again, and the fault signal is also detected again as the overcurrent is regenerated. Then, the conventional washing machine re-performs the open brake operation and re-performs the short brake operation after a predetermined time elapses. However, since the at least one of upper switching circuits is still broken, the above-described operations is repeated and the inverter module is not only broken due to the repetition of the above-mentioned operations, but a fire or the like is generated. Thus, there is a greater likelihood that the threat will be imposed.

In addition, since a conventional washing machine may not grasp which switching circuit is damaged among a plurality of switching circuits, it is difficult to open only a lower switching circuit connected to a specific stage.

Accordingly, when the motor 10 is stopped, the washing machine 1 may perform a short brake operation to control turning on/off of switching circuits to change a closed loop without repeating the above-described operation. The washing machine 1 may prevent repeated generation of the arm short and detect a broken switching circuit by changing the closed loop. Also, When the overcurrent is continuously generated even after controlling turning on/off the switching circuits, the washing machine 1 performs an open brake operation to prevent the occurrence of an accident in advance. Hereinafter, a method of controlling turning on/off of the switching circuits to stop the motor will be described in detail.

FIGS. 7, 8 and 9 are views for describing methods of stopping a motor by changing a closed loop by controlling opening and closing of switching circuits according to different embodiments. Hereinafter, an operation of stopping a motor performed by an inverter controller by controlling the six switching circuits Q11 to Q13 and Q21 to Q23 upon receiving a control signal from a controller will be described. However, since the inverter controller may be included in the controller as described above, the controller may also directly control the six switching circuits Q11 to Q13, and Q21 to Q23.

When a fault signal is detected, the inverter controller may not detect a broken upper switching circuit among the three upper switching circuits Q11 to Q13. Therefore, the inverter controller may control only some of the lower switching circuits Q21 to Q23 to be shorted to determine the broken upper switching circuit.

First, when a fault signal is detected, the inverter controller may control the second lower switching circuit Q22 and the third lower switching circuit Q23 to be shorted and the first lower switching circuit Q21 be opened among the lower switching circuits Q21 to Q23. Accordingly, referring to FIG. 7, a closed loop C2 including the input terminals b and c connected to the motor may be generated.

At this time, if the first upper switching circuit Q11 is broken, an overcurrent may not occur due to the generated closed loop C2. Therefore, residual power of the motor is consumed faster during the open brake operation through the second impedance Z2 and the third impedance Z3, and it is possible to prevent an accident such as device breakage or fire. Also, the inverter controller may determine that the first upper switching circuit Q11 is broken.

If the first upper switching circuit Q11 is not broken, an overcurrent may be generated again due to an arm short, and a fault signal may be detected again. Then, the inverter controller may recognize that the first upper switching circuit Q11 is not broken, and control the first lower switching circuit Q21 and the third lower switching circuit Q23 to be shorted, and the second lower switching circuit Q22 to be opened.

Thereby, a closed loop C3 including the input terminals a and c connected to the motor may be generated. At this time, if the second upper switching circuit Q12 is broken, an overcurrent may not occur due to the generated closed loop C3. Accordingly, residual power of the motor is consumed faster during the open brake operation through the first impedance Z1 and the third impedance Z3, and it is possible to prevent an accident such as device breakage or fire. Further, the inverter controller may determine that the second upper switching circuit Q12 is broken.

However, if the second upper switching circuit Q12 is not broken, an overcurrent may also be generated due to an arm short, and a fault signal may also be detected again. Then, as shown in FIG. 9, the inverter controller according to the embodiment may control the first lower switching circuit Q21 and the second lower switching circuit Q22 to be shorted and the third lower switching circuit Q23 to be opened.

Accordingly, a closed loop C2 including the input terminals a and b connected to the motor may be generated. At this time, if the third upper switching circuit Q13 is broken, an overcurrent may not occur due to the generated closed loop C4. Accordingly, residual power of the motor is consumed faster during the open brake operation through the first impedance Z1 and the second impedance Z2, and it is possible to prevent an accident such as device breakage or fire. In addition, the inverter controller may determine that the third upper switching circuit Q13 is broken.

However, if an overcurrent is generated in the three closed loops C2, C3, and C4 and a fault signal is detected, the inverter controller may perform an open brake operation to open all the switching circuits. At this time, even if at least one of the upper switching circuits Q11, Q12, and Q13 is shorted due to breakage and thus is not controlled, the inverter control unit may open the remaining switching circuits to perform an open brake operation to generate an open circuit.

For example, when at least two of the three upper switching circuits Q11 to Q13 are broken, an overcurrent is also generated in the three closed loops C2, C3, and C4 described above. Thus, even if the broken switching circuit is not controlled, the inverter controller may control all the other switching circuits to be opened and perform an open brake operation, thereby preventing the occurrence of an overcurrent.

The washing machine 1 according to the embodiment may control the switching circuits to create a closed loop including at least one input terminal connected to the motor so that residual power of the motor may be consumed more quickly without generating an overcurrent.

The opening and closing procedures of the lower switching circuits Q21, Q22, and Q23 are not limited to the order of FIGS. 7, 8, and 9. For example, the inverter controller may control the switching circuits to generate the closed loops in the order of the closed loop C3 of FIG. 8, the closed loop C2 of FIG. 7, and the closed loop C4 of FIG. 9 based on whether or not a fault signal is continuously detected.

In addition, the washing machine 1 according to the embodiment is applicable to all of N phase motors (N≧N), and a type and number of closed loop that may be generated according to the number of phases of the motor may vary. Hereinafter, an operation flow of the washing machine for stopping the three-phase motor will be briefly described.

FIG. 10 is a flowchart for describing a method of controlling switching circuits based on a number of times of detection of a fault signal in stopping a three-phase motor according to an embodiment.

A washing machine may control driving of a motor by controlling switching elements in an inverter module based on at least one of detection of a fault signal and a number of times of detection of the fault signal.

For example, if a fault signal is not detected (900), the washing machine may perform a short brake operation to cause the motor to stop faster (905). In addition, if fault signal is not detected, the washing machine may stop the motor according to various stopping methods.

For example, when washing operation is completed and the motor is stopped, the washing machine may stop the motor by performing at least one of deceleration control operation for decelerating the motor and a short brake operation by a control signal based on a comparison result between the actual current and the command current. As another example, when the spin-drying mode is completed and the motor is stopped, the washing machine may stop the motor by performing at least one of an open brake operation and a short brake operation described above.

Control data, control algorithm, and the like related to the method of stopping the motor according to an operation state and an operation mode may be pre-stored in a memory provided in the washing machine, and a controller of the washing machine may control components of the washing machine by generating a control signal using data pre-stored in the memory.

If a fault signal is detected (910), the washing machine may perform a two-phase short brake operation to short the switching circuits connected to the V and W stages among the lower switching circuits connected to the U, V, and W stages (920). For example, as shown in FIG. 7, the washing machine may control the second lower switching circuit Q22 connected to the V stage and the third lower switching circuit Q23 connected to the W stage to be shorted, and the first lower switching circuit Q21 to be opened.

A fault signal is detected even after the second lower switching circuit Q22 connected to the V stage and the third lower switching circuit Q23 connected to the W stage are shorted, that is, if the fault signal is detected twice (925), the washing machine may perform a two-phase short brake operation at the U and W stages. For example, the washing machine may control the first lower switching circuit Q21 connected to the U stage and the third lower switching circuit Q23 connected to the W stage to be shorted and the second lower switching circuit Q22 connected to the V stage to be opened as shown in FIG. 8 (930).

A fault signal is detected even after the first lower switching circuit Q21 connected to the U stage and the third lower switching circuit Q23 connected to the W stage are shorted, that is, if a fault signal is detected three times, the washing machine may control the first lower switching circuit Q21 connected to the U stage and the second lower switching circuit Q22 connected to the V stage to be shorted and the third lower switching circuit Q23 connected to the W stage to be opened (940).

A fault signal is detected even after a closed circuit is constituted by controlling the first lower switching circuit Q21 and the second lower switching circuit Q22 connected to the V stage to be shorted, that is, if the fault signal exceeds three times, the washing machine may perform an open brake operation to prevent an accident caused by repetition of the arm short (945).

Data on a number of times of detection of the fault signal for performing the open brake operation may be pre-stored in a memory of the washing machine. For example, the number of times of detection of the fault signal for performing the open brake operation may be preset by a designer or user and pre-stored in the memory of the washing machine and may be changed later. Accordingly, the open brake operation is not performed only when the fault signal is detected four or more times, and the washing machine may immediately perform the open brake operation when the fault signal is detected M times or more (M≧1).

Hereinafter, an operation flow of the washing machine will be briefly described.

FIG. 11 is a flowchart for describing operation of a washing machine according to an embodiment.

Referring to FIG. 11, a washing machine may control driving of the motor according to the operation mode (1000). For example, when the washing command is input by a user, the washing machine does not immediately start the motor. Instead, the washing machine opens a water supply valve to supply water to a washing tub and rotates a pulsator by supplying a driving current to the motor by controlling an inverter module after water is supplied thereto.

When a washing operation, spin-drying operation, or the like is completed or a stop command is input, the washing machine may stop the motor. For example, the washing machine may perform a deceleration control operation, an open brake operation, or a short brake operation, or the like.

The washing machine may detect whether a fault signal is generated in the inverter module due to an overcurrent (1010), and control a plurality of switching circuits in the inverter module based on the detection result (1020). For example, the washing machine may control opening and closing of the plurality of switching circuits in the inverter module based on at least one of detection results of the occurrence of a fault signal due to the overcurrent and the number of occurrences of the fault signal.

For example, three lines may be provided in the inverter module, three lines may be connected in parallel to each other, and each line may be connected to upper switching circuits and lower switching circuits. If the upper switching circuit and the lower switching circuit are simultaneously shorted on the same line, an overcurrent is supplied through a rectifier, so that damage of the inverter module as well as a fire may be generated.

Therefore, when performing a short brake operation in which all lower switching circuits are shorted in a state where at least one of the three upper switching circuits is broken, the upper switching circuit and the lower switching circuit may be simultaneously shorted on at least one same line, and various problems arise.

Thus, the washing machine according to the embodiment may perform the short brake operation to control some of the three lower switching circuits to be shorted to stop the motor more quickly and safely. The detailed descriptions of the short brake operation to control some of the plurality of lower switching circuits to be shorted have been given above and will be omitted.

In the washing machine according to the embodiment, if the fault signal is repeatedly detected after repeated short brake operations performed by changing the lower switching circuits to be shorted among the plurality of lower switching circuits, the washing machine may perform an open brake operation focusing on safety rather than stopping the motor faster.

Configurations illustrated in the embodiments and the drawings described in the present specification are only the preferred embodiments of the present disclosure, and thus it is to be understood that various modified examples, which may replace the embodiments and the drawings described in the present specification, are possible when filing the present application.

The terms used in the present specification are used to describe the embodiments of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. It will be understood that when the terms “includes,” “comprises,” “including,” and/or “comprising,” when used in this specification, specify the presence of stated features, figures, steps, components, or combination thereof, but do not preclude the presence or addition of one or more other features, figures, steps, components, members, or combinations thereof.

It will be understood that, although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another. For example, a first component could be termed a second component, and, similarly, a second component could be termed a first component, without departing from the scope of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of associated listed items.

As used herein, the terms “unit”, “device, “block”, “member”, or “module” refers to a unit that may perform at least one function or operation, and may be implemented as a software or hardware component such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). However, the term “unit”, “device”, “block”, “member”, or “module” is not limited to software or hardware. The “unit”, “device”, “block”, “member”, or “module” may be stored in accessible storage medium, or may be configured to run on at least one processor.

Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A washing machine comprising:

a motor configured to generate a rotational force;

an inverter module with a plurality of switching circuits installed therein and configured to adjust a driving current supplied to the motor; and

a controller configured to detect whether a fault signal is generated by an overcurrent in the inverter module and to control opening and closing of at least one of the plurality of switching circuits based on a detection result of an occurrence of the fault signal when controlling driving of the motor.

2. The washing machine according to claim 1, wherein when stopping the motor, the controller controls opening and closing of at least one of the plurality of switching circuits based on at least one of the detection result of the occurrence of the fault signal and a detection result of a number of occurrences of the fault signal.

3. The washing machine according to claim 1, wherein the plurality of switching circuits comprises at least one upper switching circuit and at least one lower switching circuit.

4. The washing machine according to claim 3, wherein when controlling driving of the motor, the controller performs a short brake operation by controlling some of a plurality of lower switching circuits to be shorted and other lower switching circuits to be opened when the fault signal is detected.

5. The washing machine according to claim 4, wherein the controller performs a short brake operation by controlling opening and closing of at least one of the lower switching circuits when a second fault signal is detected within a predetermined time after detection of a first fault signal.

6. The washing machine according to claim 3, wherein when controlling driving of the motor, the controller controls at least one of the plurality of lower switching circuits to be shorted to generate a closed loop comprising at least one of a plurality of input terminals connected to the motor to supply a driving current when the fault signal is detected.

7. The washing machine according to claim 6, wherein the controller changes opening and closing of at least one of a plurality of lower switching circuits to perform a short brake operation through another closed loop different from the closed loop when a second fault signal is detected within a predetermined time after detection of a first fault signal.

8. The washing machine according to claim 1, wherein the controller performs an open brake operation by controlling at least one of the plurality of switching circuits when the fault signal is detected more than a predetermined number of times.

9. The washing machine according to claim 3, wherein the controller controls opening and closing of at least one of the lower switching circuits to determine whether at least one of the upper switching circuits is broken.

10. A method of controlling a washing machine, the method comprising:

controlling driving a motor in accordance with an operation mode;

detecting a fault signal generated by an overcurrent in an inverter module when controlling driving of the motor, and

controlling a plurality of switching circuits comprised in the inverter module based on a detection result of the fault signal.

11. The method of according to claim 10, wherein the controlling of a plurality of switching circuits is performed by controlling the plurality of switching circuits based on at least one of the detection result of an occurrence of the fault signal and a detection result of a number of occurrences of the fault signal.

12. The method of according to claim 11, wherein the controlling of a plurality of switching circuits further comprises:

performing a short brake operation by controlling some of a plurality of lower switching circuits to be shorted and other lower switching circuits to be opened when the fault signal is detected.

13. The method of according to claim 12, wherein the controlling of a plurality of switching circuits further comprises:

performing a short brake operation by controlling at least one of the lower switching circuits when a second fault signal is detected within a predetermined time after detection of a first fault signal.

14. The method of according to claim 10, wherein the controlling of a plurality of switching circuits further comprises:

performing a short brake operation by controlling at least one of a plurality of lower switching circuits to be shorted to generate a closed loop comprising at least one of a plurality of input terminals connected to the motor to supply a driving current when the fault signal is detected.

15. The method of according to claim 14, wherein the controlling of a plurality of switching circuits further comprises:

controlling opening and closing of at least one of the plurality of lower switching circuits to perform a short brake operation through another closed loop different from the closed loop when a second fault signal is detected within a predetermined time after detection of a first fault signal.

16. The method of according to claim 10, wherein the controlling of a plurality of switching circuits further comprises:

performing an open brake operation by controlling at least one of the plurality of switching circuits when the fault signal is detected more than a predetermined number of times.

17. The method of according to claim 10, wherein the plurality of switching circuits comprises at least one upper switching circuit and at least one lower switching circuit, and

the controlling of a plurality of switching circuits further comprises determining whether the at least one upper switching circuit is broken by controlling opening and closing of the at least one lower switching circuit.