KR101770425B1 - Refrigerator and controlling method thereof - Google Patents

Abstract

This embodiment relates to a refrigerator.
The refrigerator according to the present embodiment includes a compressor including a compression mechanism for compressing a refrigerant and an electric motor for operating the compression mechanism and equipped with a stator and a rotor rotated with respect to the stator; An inverter including a plurality of switching elements and supplying an AC output power of a predetermined frequency and a predetermined magnitude by a switching operation of the switching element to drive the motor; And estimating position information of the rotor with respect to the stator of the motor based on the output current input to the electric motor; Wherein the control unit includes a control unit including a storage unit for storing set position information of the rotor formed by a linear or non-linearized table according to a current, and the controller controls the motor to be driven at a driving frequency of a predetermined first driving frequency interval And a second driving stage driven by the driving frequency in a second driving frequency interval according to a magnitude of a speed command and an output current supplied to the motor, wherein the setting position information and the estimated position information The control of the electric motor by the first driving step is terminated, and when the difference between the second And characterized in that for starting the control of the motor by the same steps.

Description

[0001] The present invention relates to a refrigerator and a refrigerator,

The present invention relates to a refrigerator.

A refrigerator is a household appliance for storing food in refrigeration or freezing.

Generally, a refrigerator is a device that can keep a food fresh for a predetermined period by reducing the temperature of a freezing room or a refrigerating room while repeating a refrigeration cycle in which a refrigerant compresses, condenses, expands, and evaporates.

The refrigerator includes a compressor for compressing refrigerant into a high-temperature and high-pressure gas refrigerant, a condenser for condensing the refrigerant having passed through the compressor to liquid refrigerant of high temperature and high pressure, and an expansion valve And an evaporator for evaporating the refrigerant having passed through the expansion valve to the low-temperature and low-pressure gaseous refrigerant while absorbing heat in the freezing chamber or the refrigerating chamber to maintain the temperature inside the freezing chamber or the refrigerating chamber at a low temperature.

In this case, the compressor may include an electric motor for providing a rotational force to compress the refrigerant, and may further include an inverter for controlling a current input to the electric motor.

The motor includes a stator and a rotor rotated with respect to the stator. When the inverter for driving the motor is provided, a relative position of the rotor with respect to the stator is detected, The current is input.

The relative position may be detected by a hole sensor for detecting the physical position of the rotor, or the position of the rotor may be estimated and detected based on a current value input to the electric motor without using the sensor And controls the electric motor based on the detected position value and the speed command for the motor.

At this time, the drive for detecting the relative position of the rotor without a separate sensor is called sensorless driving.

However, in the sensorless driving process, an error of a certain magnitude occurs between the estimated position and the actual position of the rotor, and when the error is generated, the current based on the estimated position is input to the motor There is a problem that the rotation efficiency of the electric motor is lowered.

It is an object of the present invention to propose a control method of a refrigerator and a refrigerator in which an error between an estimated position and an actual position of the rotor is minimized in a sensorless drive process in which the motor is driven without a separate rotor position detection sensor .

Another object of the present invention is to provide a refrigerator in which the driving efficiency of the electric motor is increased as the error between the estimated position and the actual position of the rotor is minimized.

A refrigerator according to one aspect of the present invention includes: a compressor including a compression mechanism for compressing a refrigerant; an electric motor for operating the compression mechanism, the electric motor including a stator and a rotor rotated about the stator; An inverter including a plurality of switching elements and supplying an AC output power of a predetermined frequency and a predetermined magnitude by a switching operation of the switching element to drive the motor; And estimating position information of the rotor with respect to the stator of the motor based on the output current input to the electric motor; Wherein the control unit includes a control unit including a storage unit for storing set position information of the rotor formed by a linear or non-linearized table according to a current, and the controller controls the motor to be driven at a driving frequency of a predetermined first driving frequency interval And a second driving stage driven by the driving frequency in a second driving frequency interval according to a magnitude of a speed command and an output current supplied to the motor, wherein the setting position information and the estimated position information The control of the electric motor by the first driving step is terminated, and when the difference between the second And characterized in that for starting the control of the motor by the same steps.

A method of controlling a refrigerator according to an aspect of the present invention includes: a first driving step in which an electric motor is driven at a driving frequency of a predetermined first driving frequency interval; A second driving step in which the motor is driven at the driving frequency in a second driving frequency interval based on a speed command and an output current supplied to the motor; Wherein the control unit is configured to calculate the estimated position information of the rotor with respect to the stator based on the output current input to the motor and the position of the rotor in accordance with the output current, Comparing the setting position information to determine a switching point of the electric motor from the first driving step to the second driving step; And switching the driving step of the electric motor from the first driving step to the second driving step.

According to the proposed embodiment, as the alignment position of the rotor and the stator of the motor performing the compression operation of the compressor is aligned and rotated at a position where the rotation efficiency is maximized, the rotation drive efficiency of the motor is maximized There are advantages to be able to.

Further, as the rotor of the electric motor is rotationally driven by a first driving step in which the rotor rotates at a low speed and a second driving step in which the rotor is smoothly driven by the first driving step, Efficiency is maximized.

1 is a perspective view illustrating a refrigerator according to an embodiment of the present invention;
FIG. 2 and FIG. 3 are views showing the construction of a refrigeration cycle according to an embodiment of the present invention; FIG.
4 is a view showing a driving structure of a motor of a refrigerator according to the present embodiment.
5 is a view showing the configuration of the control unit of FIG.
6 is a diagram showing a driving step of an electric motor according to the present embodiment.
7 is a flowchart showing a method of driving a motor of a refrigerator according to the present embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a configuration of a refrigerator according to an embodiment of the present invention, and FIGS. 2 and 3 are views showing a configuration of a refrigeration cycle according to an embodiment of the present invention.

1 to 3, a refrigerator 1 according to an embodiment of the present invention includes a main body 10 for forming a refrigerating chamber 20 and a freezing chamber 30. The refrigerating chamber 20 is provided on the upper side of the freezing chamber 30 and the refrigerating chamber 20 and the freezing chamber 30 are partitioned by the partition wall 17.

The refrigerator 1 further includes refrigerating compartment doors 11 and 12 and a freezing compartment door 15 for selectively shielding the refrigerating compartment 20 and the freezing compartment 30, respectively. The refrigerator compartment doors 11 and 12 are rotatably coupled to the main body 10 and the freezer compartment door 15 is provided so as to be drawn out to the front of the freezer compartment 30.

In the rear lower portion of the main body 10, a machine room 35 in which a plurality of structures constituting the refrigeration cycle are accommodated is formed.

The machine room 35 is provided with a compressor 60 for compressing the refrigerant at high temperature and high pressure, a condenser 70 and a condensing fan 72 for condensing the refrigerant discharged from the compressor 60, And an expansion device 80 for reducing the pressure of the refrigerant to a low-temperature low-pressure refrigerant.

An evaporator (90) is provided on the upper side of the machine room (35) to evaporate the refrigerant that has passed through the expansion device (80) to generate cold air. The evaporator (90) is disposed in the rear space of the freezing chamber (30).

On the other hand, the compressor 60 includes a compression mechanism (not shown) for compressing the refrigerant R to a predetermined pressure and an electric motor 110 (see FIG. 4) for driving the compression mechanism.

The compression mechanism according to the present embodiment may be, for example, a reciprocating mechanism such as a piston.

The motor 110 has the stator and the rotor, and alternating current power or direct current power of each frequency of a predetermined frequency is applied to the coil of each stator, so that the rotor rotates. As the type of the electric motor 110, various types such as BLDC (blushless DC) electric motor and synRM (Synchronous Reluctance Motor) can be used.

Meanwhile, the refrigerator according to the present embodiment includes a motor driving apparatus 100 for driving the electric motor 110. Hereinafter, the configuration of the electric motor drive apparatus 100 will be described in detail.

4 is a view illustrating a driving structure of a motor of a refrigerator according to the present embodiment.

2, the motor driving apparatus 100 of FIG. 2 includes a converter 140, an inverter 130, a control unit 120, an input current detection unit n1, (n2 to n4). The motor driving apparatus 100 of FIG. 4 may further include a reactor L, a smoothing capacitor C, a dc voltage detection unit B, and the like.

The reactor L is disposed between the power source 150 and the converter 140 to which an AC power of, for example, 130 V-60 Hz is input, and performs a power factor correcting or boosting operation. The reactor L may also function to limit the harmonic current due to the fast switching of the converter 140. [

The input current detection unit n ₁ can detect the input current i _s input from the power supply unit 150. For this, a current sensor, a current transformer (CT), a shunt resistor, or the like may be used.

The detected input current i _s is a discrete signal in the form of a pulse and is input to the control unit 120 for estimation of the input voltage v _s and generation of the converter switching control signal S ₁ .

The converter 140 converts the power supply unit 150, which has passed through the reactor L, into DC power and outputs the DC power. Although the power supply unit 150 is shown as a single-phase AC power source in the figure, it may be a three-phase AC power source.

The internal structure of the converter 140 is also changed depending on the type of the power source unit 150. [ For example, in the case of a single-phase AC power source, a half-bridge type converter in which two switching elements and four diodes are connected may be used, and in the case of a three-phase AC power source, six switching elements and six diodes may be used.

The converter 140 includes a switching element and performs a boost operation, a power factor correction, and a DC power conversion by a switching operation. Meanwhile, the converter 140 may be a diode or the like and perform a rectifying operation without a separate switching operation.

The smoothing capacitor C is connected to the output terminal of the converter 140. The converted DC power outputted from the converter 140 is smoothed.

Hereinafter, the output stage of the converter 140 is referred to as a dc stage or a dc link stage. At the dc stage, a smoothed direct current voltage is applied to the inverter 130.

The dc voltage detection unit n ₅ can detect the _dc voltage V _dc at both ends of the smoothing capacitor C. For this purpose, the dc voltage detection unit n ₅ may include a resistance element, an amplifier, and the like. The detected dc terminal voltage V _dc is a discrete signal in the form of a pulse and is input to the control unit 120 for estimation of the input voltage v _s and generation of the converter switching control signal S ₂ .

The inverter 130 includes a plurality of inverter switching elements. The inverter 130 converts the smoothed direct current power to a three-phase alternating current power of a predetermined frequency by the on / off operation of the switching element, and outputs the three-

At this time, the electric motor 110 may be provided with a three-phase electric motor in which three coils to which three-phase AC power is input are Y-connected.

The inverter 130 is constituted by a pair of upper arc-shaped switching elements Sa, Sb, Sc and lower arm switching elements S'a, S'b, S'c connected in series with each other. A total of three pairs of upper and lower arm switching elements are connected to each other in parallel (Sa, S'a, Sb, S'b, Sc, S'c). Diodes are connected in anti-parallel to each switching element Sa, S'a, Sb, S'b, Sc, S'c.

The plurality of switching elements Sa, S'a, Sb, S'b, Sc and S'c provided in the inverter 130 are controlled based on the inverter switching control signal S ₁ from the controller 120 , And outputs the three-phase power having a predetermined frequency to the motor 110 by performing on / off operation.

The first to third upper arm switching elements Sa, Sb and Sc and the first to third lower arm switching elements S'a, S'b and S'c are connected to the first, the first to be connected to the coil (L) on the connection node 33 _{(n 6, n 7, n} 8) that is provided, the switching element (Sa, S'a, Sb, S'b, Sc, S ' c so that the power of the three phases is inputted to the electric motor 110 by the switching on / off operation of the three phases.

The control unit 120 generates an inverter switching control signal S ₁ for controlling on / off operations of the switching elements Sa, S'a, Sb, S'b, Sc, and S'c with respect to the inverter 130 ).

At this time, the control unit 120 outputs a plurality of inverter switching control signals S ₁ according to a plurality of driving stages in accordance with the driving state of the motor 110.

On the other hand, first to third shunt resistors R1, R2 and R3 are provided on the other side of the first to third lower arm switching elements S'a, S'b and S'c.

The driving step of the motor 110 includes an initial aligning step for aligning the rotor inside the electric motor 110, a first driving step for rotationally driving the rotor after the initial aligning step is performed, After the first driving step is performed, the frequency and phase angle of the output current (i _o ) according to the constant speed command and the power of the three phases output to the motor 110 are fed back, and the inverter switching And a second driving step of outputting the control signal S ₁ .

In order to align the initial position of the rotor at the start of the rotation operation of the electric motor 110 in the initial alignment step, the controller 120 controls the Y-connected three-phase circuit of the electric motor 110 from the inverter 130, A DC voltage of a predetermined magnitude is applied to the rotor 110 so that the rotor can be positioned at a specific position within the electric motor 110.

Then, after the initial alignment step is performed, the first driving step of rotating the rotor at a predetermined frequency is performed, and when the rotor is driven to rotate at a predetermined speed or more, the controller 1200 controls the motor (110) to the second driving step.

Hereinafter, the operation of the second driving step will be described in detail.

First, the output current detectors n ₂ , n ₃ , and n ₄ connected to the respective phases detect the output current i _o flowing between the inverter 130 and the three-phase motor 110. That is, the current flowing in the electric motor 110 is detected. The output current detection units (n ₂ , n ₃ , n ₄ ) can detect all the output currents of the respective phases or can detect the output currents of one or two phases using three-phase equilibrium.

The output current detection units n ₂ , n ₃ and n ₄ may be located between the inverter 130 and the motor 110. A current sensor, a current transformer (CT), a shunt resistor, have. For example, one end of the shunt resistor may be connected to the three lower arm switching elements S'a, S'b, S'c of the inverter 130, respectively.

The detected output current i _o can be applied to the control unit 120 as a discrete signal in the form of a pulse and is used to estimate the input current based on the detected output current i _o Can be used. In addition, (i _o) detected output current, may be used to generate the inverter switching control signal (S _1).

Control unit 120, an output current detector (n _2, n _3, n ₄₎ the position of the motor 110 based on the output current (i _o) detected in, that estimates the position of the rotor of the electric motor 110 And the rotational speed of the electric motor 110 can be calculated. In addition, based on the estimated position and rotation speed, various control operations are performed to drive the motor 110 according to the speed command to generate an inverter switching control signal S ₁ having a variable pulse width, do.

In this manner, the output current is detected without using a separate motor position detecting element or the like, the position and speed of the electric motor 110 are estimated according to the output current, and the feedback control is performed so that the estimated speed follows the speed command Is referred to as a control based on a sensor algorithm, and the driving step of the motor 110 by the sensorless algorithm control is referred to as the second driving step according to the present embodiment.

The control operation by the sensorless algorithm, that is, the driving by the second driving step is performed when the rotation speed of the electric motor 110 is equal to or more than a predetermined value, It is possible.

That is, when the rotational speed of the electric motor 110 becomes equal to or greater than a predetermined value after the electric motor 110 is driven to the first driving phase, the second driving phase may be performed.

Then, the control unit 120 controls the switching operation of the inverter 130. To this end, the control unit 120, an output current detector (n _2, n _3, n _4), the output current (i _o) the input received, generates the inverter switching control signal (S1) the drive 130 it is detected in . The inverter switching control signal S1 may be a switching control signal for pulse width modulation (PWM).

Detailed operation of the output of the inverter switching control signal S1 in the control unit 120 will be described later with reference to Fig.

On the other hand, the control unit 120 can also control the switching operation of the converter 140. [ To this end, the control part 120 receives the dc bus voltage (Vdc) detected by the dc terminal voltage detecting unit (n _5), generates a converter switching control signal (S2) can be output this to the converter (140) . The converter switching control signal S2 may be a PWM switching control signal.

delete

Hereinafter, the configuration of the control unit 120 will be described in detail.

5 is a diagram showing the configuration of the control unit of FIG.

5, the control unit 120 includes an estimation unit 121, a current command generation unit 122, a voltage command generation unit 124, a torque compensation unit 123, a switching control signal output unit 125, And a comparison unit 126.

Although not shown in the drawings, the apparatus may further include an axial conversion unit that converts the three-phase output current _io into a d-axis and q-axis currents or a d-axis and q-axis current into three-phase currents.

The estimator 121 estimates the position information v of the rotor according to the electrical angle or phase of the mechanical angle based on the detected output current _io . For example, the mechanical equations and electric equations of the electric motor 110 can be compared with each other, and the position information v of the rotor and the rotational speed of the electric motor 110 can be estimated accordingly. That is, by estimating the position information v of the rotor, the rotational speed of the electric motor 110 can be estimated according to the positional change of the position information v.

At this time, the rotational speed and position information v of the electric motor estimated by the estimating unit 121 is referred to as estimated position information v2.

The electric angle or the mechanical angle of the electric motor 110 can be estimated using the position of the rotor. The relationship between the normal machine angle and the electrical angle is such that the period of the mechanical angle has a relationship of the number of poles of the electric motor 110 / twice as compared with the electric angle.

Here, θ _Me represents the mechanical angle, and θ _e represents the electrical angle. For example, if the six poles of poles of the motor 110, has a relationship of θ _Me = 3θ _e, have a relationship in a case where the number of poles of the motor 110, four poles, θ _Me = 2θ _e.

That is, when the six poles of poles of the electric motor (110), in each machine (θ _Me) 360˚, an electrical angle (θ _e) of 120˚ cycle is presented a corresponding three, four poles of poles of the electric motor 110 , Two electrical angles? _E of 180 占 cycle correspond to each other within 360 占 of the mechanical angle? _Me .

The current command generation section 122 generates the current command value i ^* _d based on the speed command value v ^* excluding the estimated rotational speed v2 in the first driving step, i.e., the pre-control step of the sensorless control step. i ^* _q ). The current command value i ^* _d , i ^* _q is generated based on the estimated rotational speed v2 and the speed command value v ^{* in} the second driving step, i.e., the sensorless controlling step.

In the second driving step, for example, the current command generation section 122 performs PI control based on the difference between the estimated speed and the speed command value v ^* in accordance with the estimated position information v, The command value (i ^* _d , i ^* _q ) can be generated. To this end, the current command generator 122 may include a PI controller (not shown). It is also possible to further include a limiter (not shown) for limiting the current command value (i ^* _d , i ^* _q ) so that it does not exceed the allowable range.

The voltage command generation unit 124 generates the voltage command values v ^* _d and v ^* based on the calculated current command values i ^* _d and i ^* _{q in} the first driving step, that is, ^* _q ). And, the second driving step, that is, in the sensorless control step, on the basis of the output (i _o) current detection and the calculated current command value _{^{(i * d, i * q}} ) voltage command values (v ^* _d, v ^* _q ).

In the second drive step, for example, the voltage command generation unit 124 generates a voltage command based on the difference between the detected output current (i _o ) and the calculated current command value (i ^* _d , i ^* _q ) To generate voltage command values (v ^* _d , v ^* _q ). To this end, the voltage command generation unit 124 may include a PI controller (not shown). It is also possible to further include a limiter (not shown) for limiting the level so that the voltage command values v ^* _d and v ^* _q do not exceed the permissible range.

The torque compensating unit 123 compensates the torque command v ^* of the mechanical angle θ _M estimated by the estimating unit 110 or the first and second torque commands v ^* and v ^* The second machine angles? _Me1 and? _Me2 are sequentially detected and the maximum speed mechanical angle? _M is calculated based on the detected first and second machine angles? _Me1 and? _Me2 , The optimum load pattern table which minimizes the speed ripple according to the maximum speed mechanical angle (? _M ) of the load torque pattern is selected.

The torque compensating unit 123 generates and outputs the compensation current instruction value i ^* _c in accordance with the calculated maximum speed mechanical angle [theta] _M so as to compensate the speed ripple at the constant speed operation due to the load torque , The speed ripple can be compensated.

On the other hand, in the comparator 126, the setting position information v1 of the rotor stored in the storage unit 127 in correspondence with the speed command value v ^* Estimated position information v2 is input and compared.

That is, the setting position information v1 indicates an electrical angle or a phase angle of the mechanical angle according to the position of the rotor when the electric motor 110 is driven according to the first driving step. For example, the output current io ) In a linear or non-linearized plot according to the following equation.

The comparing unit 126 compares the set position information v1 with the estimated position information v2 to determine whether to switch from the first driving step to the second driving step.

Hereinafter, the driving step of the electric motor 110 will be described in detail.

FIG. 6 is a diagram illustrating driving steps of the motor according to the present embodiment.

6 shows a current change value with respect to any one of the three phases applied to the electric motor 110. In FIG.

The supply current supplied to the electric motor 110 according to the present embodiment is, for example, supplied in the form of a sinusoidal wave for a period of 180 [deg.], And supplied to a phase different from the current supplied to any phase The supply period of the current is controlled by a 180 ° energization method in which at least a part of the current is overlapped.

The power supplied to the electric motor 110 may be controlled by PWM (Power Width Modulation).

Referring to FIG. 6, the driving step of the electric motor 110 according to the present embodiment includes an initial alignment step R1, a first driving step R21, and a second driving step R22.

More specifically, in the initial alignment step (R1), the rotor, which is provided at a predetermined angle, is in an initial alignment state in which the magnetic flux of the stator and the magnetic flux of the rotor cross each other, .

At this time, in the initial alignment step R1, the current supply to the motor 110 is performed for a predetermined time with a direct current having a size of 1A, for example, and the time during which the initial alignment step (R1) And can be stored in advance.

Then, when the initial alignment step (R1) is completed, a first driving step (R21) for supplying current to the motor (11) at a driving frequency corresponding to a first driving frequency interval of a predetermined size is performed.

More specifically, the first driving step R21 includes a first driving step R211 for controlling the current supplied to the motor 11 within the first driving frequency interval, and a first driving step R211 during the initial driving step R211 And a switching time determination step R212 for determining the switching time from the step R21 to the second driving step R22.

At this time, in the process of performing the initial driving step R211, the driving frequency gradually increases with time in the first driving frequency interval. That is, the control unit 120 controls the electric motor 110 such that the speed of the electric motor 110 is gradually increased when the rotor rotates at a low speed.

The comparator 126 of the controller 120 compares the set position information v1 stored in the storage unit 127 and the estimated position information v2 in the estimating unit 121 during the initial drive step 211 ) To determine a switching point of time from the first driving step R21 to the second driving step R22.

At this time, when the phase angle difference of the rotor according to the set position information v1 and the estimated position information v2 is formed within a certain range, the controller 120 controls the first driving step R21 to the second driving step R22 So that the driving phase of the electric motor 110 is advanced.

When the difference between the set position information v1 and the estimated position information v2 is compared with 0% to 5% in the motor drive device 100 of the refrigerator 1 according to the present embodiment, The first driving step R21 is terminated and the driving of the electric motor 110 is progressed in accordance with the second driving step R22.

When the comparison unit 126 compares the set position information v1 and the estimated position information v2 and the control unit 120 performs the end of the first driving step R21 and the progress of the second driving step R22 the electric motor 110, a second driving stage (R22) by the control unit 120, that is, the speed command value (v ^*) and the output current and the rotor position of the (i _o), the electric motor 110 by a feedback value of the an estimated, and performs sensorless drive for controlling the output current (i _o) value for the rotational speed and the motor 110 of the motor 110, i.e. to the driving frequency included in a second drive frequency area.

At this time, the magnitude of the driving frequency in the second driving frequency interval of the second driving step R22 is formed to be larger than the magnitude of the driving frequency in the first driving frequency interval of the first driving step R21.

When the supply of power to the motor 110 is performed by the PWM method, the amount of the uniformity supplied to the motor 110 increases in accordance with the magnitude of the frequency, The rotational speed is set to be smaller than the rotational speed of the electric motor 110 in the second driving step R22, and is relatively low-speed driven.

That is, in order to prevent the speed ripple from being generated during the initial driving operation due to inertia according to the self weight of the rotor in the course of starting the driving operation of the rotor, , That is, at a low speed, and drives the electric motor 110 at the second driving step, that is, the driving speed by the speed command value, when the rotor is stably rotated.

Hereinafter, a control method of the refrigerator electric motor 110 according to the present embodiment will be described in detail.

7 is a flowchart showing a method of controlling the electric motor of the refrigerator according to the present embodiment.

7, when it is determined whether a drive start signal for the motor 110 is input (S100), the controller 120 controls the motor 110 so that the rotor of the motor 110 is aligned in the initial state An initial alignment step R1 is performed (S200).

Then, the control unit 120 operates the motor 110 as the first driving step R21 with the driving frequency of the predetermined first driving frequency interval (S300).

At this time, the driving frequency at the first driving frequency may gradually increase with time as described above.

And, while the first drive stage (R21) in progress, estimator 121 based on the output current (i _o) to be supplied to the electric motor 110 and estimate the estimated position information of the rotor (v2) (S400).

The comparison unit 126 then compares the set position information v1 stored in the storage unit 127 and the estimated position information v2 obtained from the estimator to calculate the set position information v1 and the estimated position information v2, It is determined whether the difference in phase angle of the rotor is within 5% (S500).

At this time, when the phase angle difference of the rotor according to the estimated position information (v2) that is formed within 5%, the controller 120 is the feedback of the motor 110, the speed command value (v ^*) and the output current (i _o) Sensorless drive for controlling the rotational speed of the electric motor 110 and the output current ( _io ) for the electric motor 110 by estimating the position of the rotor of the electric motor 110 according to the value (S600). ≪ / RTI >

Then, it is determined whether or not an electric motor driving end signal is input (S700). If the electric motor driving end signal is inputted, the control ends. If the electric motor driving end signal is not input, (S600). ≪ / RTI >

If the motor drive start signal is not input (S100), the control is terminated.

In the step S500 of determining whether the phase angle difference of the rotor according to the set position information v1 and the estimated position information v2 is formed within 5%, the set position information v1 and the estimated position information v2 If the phase angle difference of the rotor according to the position information v2 exceeds 5%, the controller 120 controls the motor 110 to rotate at the first driving frequency R21 in step S300.

According to the proposed embodiment, as the alignment position of the rotor and the stator of the electric motor 110 that performs the compression operation of the compressor 10 is aligned and rotated at a position where the rotation efficiency is maximized, 110 can be maximized.

In addition, as the rotor of the electric motor 110 is rotationally driven by a first driving step in which the rotor is rotated at a low speed and a second driving step in which the rotor is smoothly driven by the first driving step, The rotation efficiency of the electric motor 110 is maximized.

1: Refrigerator
10: Body
60: Compressor
100: Motor drive unit
110: Electric motor
120:
130: inverter
140: Converter
R1: Initial sort step
R21: First driving step
R211: initial drive phase
R212: Step of judging conversion time
R22: second driving stage

Claims (15)

A refrigerator having a condenser, an evaporator, a compressor and an expansion valve,
A compressor including a compression mechanism for compressing the refrigerant, and a motor for operating the compression mechanism and having a rotor and a rotor rotated with respect to the stator;
An inverter including a plurality of switching elements and supplying an AC output power of a predetermined frequency and a predetermined magnitude by a switching operation of the switching element to drive the motor; And
And a controller for detecting an output current transmitted from the inverter to the motor and outputting an inverter switching control signal for controlling the on or off operation of the plurality of switching elements to the inverter based on the detected output current,
Wherein,
An estimator for estimating estimated position information of the rotor with respect to the stator of the electric motor based on an output current input to the electric motor; A storage unit for storing set position information of the rotor formed by a linear or non-linearized table,
A current command generator for generating a current command value based on at least one of the estimated position information and the speed command value,
A voltage command generator for generating a voltage command value based on the current command value and the output current;
And a switching control signal output unit for generating the inverter switching control signal based on the voltage instruction value and outputting the switching control signal to the inverter,
Wherein the electric motor is driven to a first driving stage driven with a driving frequency of a predetermined first driving frequency interval, and in the first driving stage, the current command generator generates a current command value based on the estimated position information,
Wherein when the difference between the set position information and the estimated position information is equal to or less than a predetermined size in the process of driving to the first driving step, the motor is driven to a driving frequency of a predetermined second driving frequency interval And in the second driving step, the current command generator generates a current command value based on the estimated position information and the speed command value,
Wherein the driving frequency of the second driving frequency section is greater than the driving frequency of the first driving frequency section. The method according to claim 1,
When the difference between the set position information and the estimated position information is 0% or more and 5% or less, the control unit terminates the control of the electric motor by the first driving step, and controls the electric motor by the second driving step Wherein the refrigerator is a refrigerator. delete The method according to claim 1,
Wherein the controller performs an initial alignment step of aligning the rotor and the stator before the first driving step of the motor is started. 5. The method of claim 4,
Wherein the output current supplied to the motor in the initial alignment step is formed of a direct current having a predetermined magnitude. delete The method according to claim 1,
Wherein the driving frequency of the second driving frequency section is gradually increased with respect to time. The method according to claim 1,
Wherein the first driving step includes:
An initial driving step of gradually increasing a driving frequency for driving the motor within the first driving frequency interval; And
And determining whether to end the first driving step and the second driving step when the driving frequency for driving the motor reaches a predetermined frequency. The method according to claim 1,
Wherein the output current of at least three phases is input to the motor, and the output current of one of the phases overlaps the output current of the other phase at least in a partial region. 1. A refrigerator comprising: a compression mechanism that compresses a refrigerant; and a compressor that operates the compression mechanism and includes a stator and a rotor that is rotated with respect to the stator,
Driving the motor to a first driving step in which the motor is driven at a driving frequency of a predetermined first driving frequency interval;
The estimating unit of the control unit estimates the rotor position information of the electric motor based on the output current and the speed command;
Wherein the controller is configured to calculate the estimated position information of the rotor with respect to the stator based on the output current input to the motor and the position of the rotor based on the output current, Comparing the set position information of the motor with the set position information of the motor to determine a switching point of time from the first driving step to the second driving step of the electric motor; And
Wherein the motor is driven to a second driving stage driven by a driving frequency of a second driving frequency interval based on a magnitude of a speed command and an output current supplied to the motor,
Wherein the step of determining the switching time point of the electric motor from the first driving step to the second driving step comprises:
When the difference between the estimated position information and the set position information of the rotor is less than a predetermined size in the course of driving the motor to the first driving step, Step < RTI ID = 0.0 >
Wherein the second driving step includes:
Wherein the current command generator of the control unit controls the inverter that drives the motor based on the speed command value of the rotor and the estimated position information of the rotor. delete 11. The method of claim 10,
Further comprising an initial alignment step of supplying a DC current of a predetermined magnitude to the motor so that the controller aligns the rotor of the motor in an initial state. 13. The method of claim 12,
Wherein the initial aligning step is performed before the first driving step is performed. 11. The method of claim 10,
Wherein the output current of at least three phases is input to the motor, and the output current of any one phase overlaps the output current of the other phase at least in a partial region. delete

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