KR20110092056A - Refrigerator and controlling method thereof - Google Patents

Abstract

PURPOSE: A refrigerator and a control method thereof are provided to prevent the inflow of over-current by resolving the abnormal driving state of a motor. CONSTITUTION: A refrigerator comprises a compressor, an inverter(130) and a control unit(120). The compressor comprises a compressing unit and a motor. The compressing unit compresses refrigerant supplying cold air to a storage room. The motor operates the compressing unit and comprises a stator and a rotor, which rotates to the stator. The inverter comprises a plurality of switching elements. The inverter supplies an AC form of current with a given frequency and a given amplitude to the motor by a switching operation of the switching element. The control unit compares the amplitude of arithmetic applied voltage with that of phase voltage applied to the inverter to determine whether the rotation of the rotor is interfered or limited.

Description

Control method for refrigerators and freezers

The present invention relates to a refrigerator.

A refrigerator is a home appliance for storing food in a chilled or frozen state.

In general, a refrigerator is a device that can keep food fresh for a certain period of time by lowering the freezing compartment or the refrigerating compartment while repeating a refrigeration cycle in which the refrigerant is compressed, condensed, expanded, or evaporated.

Such a refrigerator includes a compressor for compressing a refrigerant into a high temperature and high pressure gas refrigerant, a condenser for condensing the refrigerant passing through the compressor into a high temperature and high pressure liquid refrigerant, and an expansion valve for reducing the refrigerant passing through the condenser into a low temperature and low pressure liquid refrigerant. And a refrigerating cycle including an evaporator as a basic component that absorbs heat inside the freezing compartment or the refrigerating compartment and keeps the temperature inside the freezing compartment or the refrigerating compartment at a low temperature while evaporating the refrigerant passing through the expansion valve to a low temperature low pressure gas refrigerant.

At this time, the compressor may be provided with a motor for providing a rotational force to provide a compression force, for the compression of the refrigerant, it may further include an inverter for controlling the current input to the motor.

The motor includes a stator and a rotor that rotates with respect to the stator. When the motor is provided with an inverter for driving the motor, the motor detects a relative position of the rotor with respect to the stator and corresponds to the relative position. The current is input.

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

In this case, the driving of detecting the relative position of the rotor without a separate sensor is called a sensorless driving.

However, in the sensorless driving process, when the rotor does not move with respect to the stator by a predetermined event, that is, when the rotor is constrained, there is no separate sensor for detecting the rotation state of the rotor. It is not easy to detect the state in which the rotor is constrained.

In addition, when the rotor is restrained, whether the restraint, that is, an abnormal driving state of the motor is not detected, and the motor is normally driven, and the current is supplied to the motor, the motor may be damaged. It may be.

An object of the present embodiment is to propose a refrigerator for detecting whether the rotor of the electric motor is bound without a separate sensor when the motor is driven by a sensorless drive that is not provided with a separate sensor.

Still another object of the present embodiment is to propose a refrigerator for preventing an overcurrent according to the abnormal driving state to be introduced into the electric motor by eliminating the abnormal driving state of the electric motor when the rotation operation of the electric motor is interrupted or constrained. It is in doing it.

According to an aspect of the present invention, a refrigerator includes a compressor including a compression mechanism for compressing a refrigerant supplying cold air to the storage compartment, and a motor including a stator and a rotor that rotates with respect to the stator to operate the compression mechanism; An inverter including a plurality of switching elements, and supplying an output current having an alternating frequency of a predetermined frequency and a predetermined magnitude to the electric motor by a switching operation of the switching element; And comparing the magnitude of the arithmetic applied voltage calculated based on the output current, the inductance and the resistance of the motor, and the magnitude of the phase voltage applied to the inverter to determine whether the rotation of the rotor is interfered or constrained. And a controller for controlling the inverter to drive the electric motor in a restart mode for canceling the rotation or interference.

A control method of a refrigerator according to an aspect of the present embodiment includes the steps of controlling the inverter to drive the electric motor in the initial drive mode; Comparing the magnitude of an arithmetic applied voltage calculated based on the output current, the inductance and the resistance of the motor, and the magnitude of the phase voltage applied to the inverter to determine whether the rotation of the rotor is interfered or constrained; Controlling the inverter to drive the electric motor in a restart mode when the rotation of the rotor is interrupted or constrained; And controlling, by the controller, the inverter according to a speed command and the output current.

According to the proposed embodiment, in the process of driving the refrigerator, by detecting the rotation state of the motor of the compressor, if the rotation state is abnormal state, that is, the rotation operation is interfered or constrained, the restart operation of the motor is performed, Abnormal conditions can be resolved.

In addition, the abnormal state of the motor is not provided with a separate sensor for detecting the physical state of the rotor, such as a hall sensor, it can be detected by the detected current and voltage, the physical configuration of the motor drive device This can be simplified, and manufacturing costs can be reduced.

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

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

1 to 3, the refrigerator 1 according to the exemplary embodiment of the present invention includes a main body 10 forming the refrigerating chamber 20 and the freezing chamber 30. The refrigerating compartment 20 is provided above the freezing compartment 30, and the refrigerating compartment 20 and the freezing compartment 30 are partitioned by partition walls 17.

The refrigerator 1 further includes refrigerating compartment doors 11 and 12 and a freezing compartment door 15 that selectively shield the refrigerating compartment 20 and the freezing compartment 30, respectively. The refrigerating compartment doors 11 and 12 are rotatably coupled to the main body 10, and the freezing compartment door 15 is provided to be pulled out toward the front of the freezing compartment 30.

In the lower rear part of the main body 10, the machine room 35 which accommodates the several structure which comprises a refrigeration cycle is formed.

The machine room 35 includes a compressor 60 for compressing a refrigerant at high temperature and high pressure, a condenser 70 and a condenser fan 72 for condensing the refrigerant discharged from the compressor 60, and a refrigerant passing through the condenser 70. Expansion device 80 for reducing the pressure to a low temperature low pressure refrigerant.

Then, an upper side of the machine room 35 is provided with an evaporator 90 for evaporating the refrigerant passing through the expansion device 80 to produce cold air. The evaporator 90 is disposed in the rear space of the freezer compartment 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.

In addition, the motor 110 includes the stator and the rotor, and the AC power or the DC power of each phase of a predetermined frequency is applied to the coils of the stator of each phase so that the rotor rotates. The type of the motor 110 may be various forms such as a brushless DC (BLDC) motor and a synchronous reluctance motor (synRM).

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

4 is a view showing a driving configuration of the electric motor of the refrigerator according to the present embodiment.

Referring to FIG. 4, the motor driving apparatus 100 of FIG. 2 according to an exemplary embodiment of the present invention may include a converter 140, an inverter 130, a controller 120, an input current detector n1, and an output current detector. and (n2 to n4). In addition, the motor driving apparatus 100 of FIG. 4 may further include a reactor L, a smoothing capacitor C, a dc end voltage detector B, and the like.

The reactor L is disposed between, for example, the power supply unit 150 to which an AC power source of 130 V to 60 Hz is input and the converter 140 to perform power factor correction or step-up operation. In addition, the reactor L may perform a function of limiting harmonic currents due to the high speed switching of the converter 140.

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

The detected input current i _s is a discrete signal in the form of a pulse and is input to the controller 120 to estimate the input voltage v _s and generate the converter switching control signal S ₁ . Can be.

The converter 140 converts the power supply unit 150 which has passed through the reactor L into DC power and outputs the DC power. In the drawing, the power supply unit 150 is illustrated as a single-phase AC power source, but may be a three-phase AC power source.

The internal structure of the converter 140 also varies according to the type of the power supply 150. For example, in the case of a single phase AC power supply, 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 supply, six switching elements and six diodes may be used.

The converter 140 includes a switching element to perform a boost operation, a power factor improvement, and a DC power conversion by a switching operation. On the other hand, the converter 140 may be made of a diode or the like to perform rectification without a separate switching operation.

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

Hereinafter, the output terminal of the converter 140 is called a dc terminal or a dc link terminal. The DC voltage smoothed in the dc stage is applied to the inverter 130.

The dc terminal voltage detector n ₅ may detect a dc terminal voltage V _{dc that} is both ends of the smoothing capacitor C. To this end, the dc terminal voltage detector n ₅ may include a resistor, an amplifier, and the like. The detected dc terminal voltage (V _dc ) is detected, the dc terminal voltage (Vdc) is a discrete signal in the form of a pulse, the estimation of the input voltage (v _s ) of the converter switching control signal (S ₂ ) For generation, it may be input to the controller 120.

The inverter 130 includes a plurality of inverter switching elements, converts a smoothed DC power source into a three-phase AC power source having a predetermined frequency by on / off operation of the switching element, and outputs the same to the electric motor 110.

At this time, the motor 110 may be provided with a three-phase electric motor Y-wired three coils to the three-phase AC power input.

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

The plurality of switching elements Sa, S'a, Sb, S'b, Sc, and S'c included in the inverter 130 are based on the inverter switching control signal S ₁ from the controller 120. , Perform an on / off operation, and outputs a three-phase power source having a predetermined frequency to the motor (110).

In this case, between the first to third phase arm switching elements Sa, Sb, and Sc and the first to third lower arm switching elements S'a, S'b, and S'c, respectively, the first to third phase arm switching elements S'a, S'b, and S'c. First to third connection nodes n6 connected to the coil L of the third phase are provided, and switching on / off of the switching elements Sa, S'a, Sb, S'b, Sc and S'c. By operation, the three-phase power is input to the motor 110.

The controller 120 controls 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. )

In this case, the controller 120 outputs a plurality of inverter switching control signals S ₁ according to a plurality of driving stages according to the driving state of the motor 110.

The 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, respectively.

The driving step of the electric motor 110 may include an initial alignment step for aligning the rotor in the motor 110, a first driving step for rotating the rotor after the initial alignment step is performed, and the After the first driving step is performed, a constant speed command and a frequency and a phase angle of the output current i _o according to the power of the three phases output to the motor 110 are fed back, and the inverter is switched according to the received information. And a second driving step of outputting the control signal S ₁ .

In the initial alignment step, in order to align the initial position of the rotor at the time when the rotation operation of the motor 110 is started, the controller 120 is a Y-phased three-phase circuit of the motor 110 from the inverter 130. A DC voltage of a predetermined magnitude is applied to the rotor to allow the rotor to be positioned at a specific position inside the 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 if the rotor is rotationally driven at a predetermined speed or more, the controller 1200 is a motor 110 is driven to the second driving step.

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

First, the output current detectors n ₂ , n ₃ , n ₄ connected to each phase detect an output current i _o flowing between the inverter 130 and the three-phase electric motor 110. That is, the current flowing through the motor 110 is detected. The output current detectors n ₂ , n ₃ , and n ₄ may detect all the output currents of each phase, or may detect the output currents of one or two phases by using three-phase balance.

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

The detected output current i _o , as a discrete signal in the form of a pulse, may be applied to the controller 120, and based on the detected output current i _o , to estimate the input current. Can be used. In addition, the detected output current i _o may be used to generate the inverter switching control signal S ₁ .

The controller 120 estimates the position of the motor 110, that is, the position of the rotor of the motor 110, based on the output current i _o detected by the output current detectors n ₂ , n ₃ , n ₄ . In addition, the rotation 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, thereby generating and outputting an inverter switching control signal S ₁ having a variable pulse width. do.

In this way, the output current is detected without using a separate motor position detecting element or the like, the position and speed of the motor 110 are estimated according to the output current, and the feedback control is performed so that the estimated speed follows the speed command. This is called control by a sensorless algorithm, and the driving step of the motor 110 by the sensorless algorithm control is called 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 not performed at the initial startup of the motor 110, but is performed when the rotation speed of the motor 110 is greater than or equal to a predetermined value. It is possible.

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

In addition, the controller 120 controls the switching operation of the inverter 130. To this end, the controller 120 receives the output current i _o detected by the output current detector E, generates an inverter switching control signal S1, and outputs it to the inverter 130. The inverter switching control signal S1 may be a switching control signal for pulse width modulation (PWM).

A detailed operation of the output of the inverter switching control signal S1 in the controller 120 will be described later with reference to FIG. 3.

The controller 120 may also control a switching operation of the converter 140. To this end, the controller 120 may receive the dc terminal voltage Vdc detected by the dc terminal voltage detector B, generate a converter switching control signal S2, and output the converter switching control signal S2 to the converter 140. The converter switching control signal S2 may be a switching control signal for PWM.

The controller 120 may also control a switching operation of the converter 140. To this end, the controller 120 may receive the dc terminal voltage Vdc detected by the dc terminal voltage detector B, generate a converter switching control signal S2, and output the converter switching control signal S2 to the converter 140. The converter switching control signal S2 may be a switching control signal for PWM. The output current i _o detected by the detector E is input, generates an inverter switching control signal S1, and outputs the same to the inverter 130. The inverter switching control signal S1 may be a switching control signal for pulse width modulation (PWM).

A detailed operation of the output of the inverter switching control signal S1 in the controller 120 will be described later with reference to FIG. 5.

The controller 120 may also control the switching operation of the converter 140. To this end, the controller 120 may receive the dc terminal voltage Vdc detected by the dc terminal voltage detector B, generate a converter switching control signal S2, and output the converter switching control signal S2 to the converter 140. The converter switching control signal S2 may be a switching control signal for PWM.

In addition, the controller 120 may control a switching operation of the converter 140. To this end, the controller 120 may receive the dc terminal voltage Vdc detected by the dc terminal voltage detector B, generate a converter switching control signal S2, and output the converter switching control signal S2 to the converter 140. The converter switching control signal S2 may be a switching control signal for PWM.

In addition, the control unit 120, when the rotor of the motor 110 is interfered or constrained by the restraint factors such as the internal contact or the magnetic flux direction with the stator in the motor 110, the rotation Detects the restraint of the electrons and performs a restart operation to solve the restraint or deceleration of the rotor.

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

3 is a diagram illustrating a configuration of the controller of FIG. 2.

Referring to FIG. 3, the control unit 120 includes an estimator 121, a current command generator 122, a voltage command generator 124, a torque compensator 123, a switching control signal output unit 125, The calculator 126 and the comparer 127 are included.

On the other hand, although not shown in the drawings, the three-phase output current (i _o ) may be further included an axis conversion unit for converting the d-axis, q-axis current or the d-axis, q-axis current to three-phase current.

The estimator 121 estimates the position information v of the rotor according to the phase of the electric angle or the mechanical angle based on the detected output current i _o . For example, the mechanical equations of the electric motor 110 and the electric equations may be compared with each other, whereby the positional information v of the rotor and the rotational speed of the electric motor 110 may be estimated. That is, by estimating the positional information v of the rotor, it is possible to estimate the rotational speed of the motor 110 in accordance with the positional change of the positional information v.

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

The electric angle or the mechanical angle of the electric motor 110 may be estimated using the position of the rotor. In general, the relationship between the mechanical angle and the electrical angle is such that the period of the mechanical angle is twice the number of poles of the electric motor 110 compared to the electrical angle.

Where θ _Me represents a mechanical angle and θ _e represents an electrical angle. For example, when the number of poles of the motor 110 is six poles, the relationship is θ _Me = 3θ _e , and when the number of poles of the motor 110 is four poles, the relationship is θ _Me = 2θ _e .

That is, when the number of poles of the motor 110 is six poles, three electric angles θ _e of 120-degree cycles correspond to each other within 360 degrees of the machine angle θ _Me , and the number of poles of the motor 110 is four poles. In this case, within the machine angle θ _Me 360 degrees, two electric angles θ _e of 180 ° periods correspond to each other.

In the sensorless control step, the current command generation unit 122 generates a current command value i ^* _d , i ^* _q based on the estimated rotation speed v2 and the speed command value v ^* .

For example, the current command generation unit 122 performs PI control on the basis of the difference between the estimated speed and the speed command value v ^* according to the estimated position information v, so that the current command value i ^* _d , i ^* _q ) can be generated. To this end, the current command generation unit 122 may include a PI controller (not shown). Further, a limiter (not shown) may be further provided to limit the level so that the current command value i ^* _d , i ^* _q does not exceed the allowable range.

Voltage command generation section 124 is a voltage command value based on the in sensorless control step, the detected output current (i _o) and the calculated current command value (i ^* _d, i ^* _q), (v ^* _d, v ^* _q) Create

For example, the voltage command generation unit 124 performs the PI control based on the difference between the detected output current i _o and the calculated current command value i ^* _d , i ^* _q to perform the voltage command value v. ^* _d , v ^* _q ) To this end, the voltage command generation unit 124 may include a PI controller (not shown). Further, a limiter (not shown) may be further provided to limit the level so that the voltage command value v ^* _d , v ^* _q does not exceed the allowable range.

The torque compensator 123 generates and outputs a compensation current command value i ^* _c according to the calculated maximum speed machine angle θ _M to compensate for the speed ripple during constant speed operation due to the load torque. Speed ripple can be compensated.

On the other hand, the output current i _o is input to the calculator 127, and the calculator 127 calculates an arithmetic applied voltage V _dc ′ based on the output current i _o and the inductance λ.

In more detail, the dc terminal voltage V _dc for one of the three phases of the motor 110, that is, the phase voltage applied to the inverter 120, the output current i _o , and the inductance λ are as follows. Satisfies.

That is, the magnitude of the phase voltage (V _{dc , 1} ) for any one phase, for example, the first phase is a voltage applied to both ends of the coil (L1) of the first phase (the resistance of the first phase (R1), Product of the output voltage applied to the first phase) and the differential value of the inductance λ1 of the coil L1 of the first phase and the counter electromotive force E1 generated for the first phase according to the rotation. .

Therefore, the magnitudes of the phase voltages V _dc for the three phases satisfy the following relationship.

On the other hand, the operation unit 126 'is referred to as an arithmetic applied voltage (V _dc voltage value to be calculated by the parameters of the coil (L) arithmetic applied voltage (V _dc) ") provided in the motor 110 in the following relationship: Satisfies.

From the above relationship, the phase voltage V _{dc , 1} and the arithmetic applied voltage V _dc ′ satisfy the following relationship.

In the rotation driving process of the motor 110, the difference between the phase voltage (V _{dc , 1} ) and the arithmetic applied voltage (V _dc ') is generated by the difference of the counter electromotive force (E), the rotation of the motor 110 The back EMF always has a value greater than zero.

That is, when the rotational driving state of the motor 110 is a normal driving state, the difference between the phase voltage V _{dc , 1} and the arithmetic applied voltage V _dc ′ is formed to a certain size, that is, the magnitude of the counter electromotive force E. do.

On the contrary, when the rotational driving state of the motor 110 is an abnormal driving state, that is, the difference between the phase voltage V _{dc , 1} and the arithmetic applied voltage V _dc ′ is greater than a predetermined size, that is, the magnitude of the counter electromotive force E. It is formed small.

In the present embodiment, a criterion for determining a normal driving state and an abnormal driving state of the motor 110 may include, for example, a difference between a phase voltage V _{dc , 1} and an arithmetic applied voltage V _dc ′ of the motor 110. It can be set in the range of ± 5% of the voltage (V _{dc , 1} ).

That is, when the difference between the phase voltage V _{dc , 1} and the arithmetic applied voltage V _dc ′ of the motor 110 is greater than or equal to ± 5% of the phase voltage V _{dc, 1} , the motor 110 is driven. The state is determined to be a normal driving state, and if it is less than ± 5% of the phase voltage V _{dc , 1} , the driving state of the motor 110 is determined to be an abnormal driving state.

On the other hand, the comparator 127 receives a phase voltage V _{dc , 1} and an arithmetic applied voltage V _dc ′, and the comparator 127 receives a phase voltage V _{dc , 1} and an arithmetic applied voltage V _dc. When the difference of ') is smaller than a predetermined size, that is, the size of the counter electromotive force E, the restart signal S3 is input to the current command generation unit 122.

When the restart signal S3 is input to the current command generation unit 122, the controller 120 determines that the rotation of the motor 110 is interrupted or constrained so that the motor 110 can be driven in the restart mode. The inverter 130 is controlled, and the speed command v ^* input to the current command generation unit 122 is blocked.

In this case, the restart mode includes a first restart mode in which the control unit 120 stops the operation of the motor 110 for a first period, and a count of the number of times the first restart mode is performed by the control unit 120. When the restart mode is repeatedly performed a predetermined number of times, a second restart mode for stopping the operation of the motor 110 for a second period of time is included.

In this case, the second period may be larger than the first period, and the first period may be, for example, 1.5 seconds and the second period, for example, 150 seconds.

Hereinafter, a process of driving the motor 110 by the motor driving apparatus 100 according to the present embodiment will be described in detail.

4 is a flowchart illustrating a method of driving an electric motor of a refrigerator according to the present embodiment.

Referring to FIG. 4, it is determined whether the motor driving start signal is input (S10), and when the driving start signal is input, the controller 120 controls the inverter 130 to be driven in the initial driving mode of the motor 110. (S11).

The initial driving mode of the motor 110 supplies a direct current of a predetermined magnitude to the motor 110, aligns the magnetic flux of the rotor and the stator to cross each other, and then irrespective of the speed command v ^* . As the rotational drive of the rotor is driven for a predetermined time at a low frequency, for example, 25 to 30 Hz, in the normal driving state, that is, the sensorless driving state, the driving efficiency of the rotor relative to the stator is maximized. To be

Next, the controller 120 determines whether the rotation of the rotor of the motor 120 is interfered or restrained based on the output current i _o output to the motor 110.

In more detail, the control unit 120 determines whether the rotation of the rotor of the motor 120 is interference or restrained based on the output current i _o output to the motor 110. ) Is the arithmetic applied voltage (V _dc ') calculated based on the output current (i _o ) output to the motor 110 and the inductance (λ) of the coil (L) provided in the motor 110, and the inverter 130 Comparing the phase voltage (V _dc ) applied to the step (S12).

In operation S12, when the arithmetic applied voltage V _dc ′ and the phase voltage V _dc are compared, the controller 120 has a difference between the phase voltage V _dc and the arithmetic applied voltage V _dc ′. It is determined whether or not the set range, i.e., less than ± 10% of the phase voltage V _dc , and whether the rotation operation state of the motor 110 is an interference or restraint state, that is, an abnormal state or a normal state. .

At this time, the control unit 120 is a difference between the phase voltage (V _dc ) and the arithmetic applied voltage (V _dc ') is less than a predetermined range, that is, a range of ± 10% of the phase voltage (V _dc ), the state is preset When the time elapses (S12), counts the number of times the difference between the phase voltage (V _dc ) and the arithmetic applied voltage (V _dc ') is recorded less than ± 10% of the phase voltage (V _dc ) (S13). .

Next, it is determined whether the number of times of recording is a predetermined number of times, for example, 50 times or more (S14), and when the number of times of recording is more than the predetermined number of times, the controller 120 determines that the motor 110 restarts the first restart. To perform the mode (S15).

Further comprising: an electric motor (110) performs the first restart mode (S15) is the voltage (V _dc) and an arithmetic applied voltage (V _dc ') is the voltage (V _dc) is less than the range of over ± 5% difference Initializing the number of times to be recorded (S151), the rotation operation is stopped during the first period of the motor 110, the step of blocking the input of the speed command (v ^* ) (S152), and the motor 110 In step S153, the initial driving mode is performed.

Next, the controller 120 determines whether the difference between the phase voltage V _dc and the arithmetic applied voltage V _dc ′ is within a preset range, that is, within a range of ± 5% of the phase voltage V _dc . (S16), if it is within the range of ± 5%, it is determined whether the number of times the first restart mode (S15) has been performed is five times as an example of the predetermined number of times (S17).

When the first startup mode S15 is performed the predetermined number of times (S17), the controller 120 controls the inverter 130 to operate the motor 110 in the second restart mode (S18).

In detail, step S18 of operating the motor 110 in the second restart mode may include initializing the number of times the first restart mode is performed (S181), and rotating the motor 110 during the second period of time. The operation is stopped, and the input of the speed command v ^* is blocked (S182), and the initial driving mode of the motor 110 is performed (S183).

Next, the controller 120 determines whether the difference between the phase voltage V _dc and the arithmetic applied voltage V _dc ′ is greater than a preset range, that is, a range of ± 5% of the phase voltage V _dc . (S19), when the difference between the phase voltage (V _dc ) and the arithmetic applied voltage (V _dc ') exceeds the predetermined range, the motor 110 is normally rotated, that is, interference or restraint of the rotation operation is Judging from the resolved state.

When the rotation operation state of the motor 110 is determined to be a normal state, the controller 120 controls the inverter 130 for driving the motor 110 based on the speed command v ^* and the output current i _o . (S20).

At this time, the step (S20) of the control unit 120 controls the inverter 130 for driving the motor 110 based on the speed command (v ^* ) and the output current (i _o ), the weight of the control unit 120. A step (121) of estimating the position of the rotor of the electric motor (110) based on the speed command (v ^* ) and the output current (i _o ), and the control unit (120) estimating the position of the rotor and Based on the speed command v ^* , the sensor 130 may be a sensorless drive including controlling the inverter 130.

Next, it is determined whether the driving end signal of the electric motor 110 is input (S21), and when the driving end signal is input, the control is terminated, and when the driving end signal is not input, the control unit 120 ) Controls the inverter 130 for driving the electric motor 110 based on the speed command v ^* and the output current i _o (S20).

On the other hand, in step S10 of determining whether the motor driving start signal is input, if the driving start signal is not input, the control ends.

In operation S12 of comparing the arithmetic applied voltage V _dc ′ and the phase voltage V _dc , and determining whether the number of times of writing is greater than or equal to a predetermined number of times, the control unit 120 may perform the control operation. The difference between the phase voltage (V _dc ) and the arithmetic applied voltage (V _dc ') exceeds a preset range (for example, less than a range of ± 5% of the phase voltage (V _dc )) (S12), and the number of recordings When less than the predetermined number of times (S14), it is determined whether the step (S11) for operating the motor 110 in the initial driving mode is performed for a predetermined time (S23).

Determined that the electric motor to the when a predetermined time elapses (S23), determines the rotation state to a normal state, the control part 120 of the motor 110 on the basis of the speed command (v ^*) and the output current (i _o) ( The step S20 of controlling the inverter 130 for driving 110 is performed.

When the predetermined time has not elapsed (S23), the step of driving the electric motor 110 in the initial driving mode (S11) is performed.

Meanwhile, the controller 120 determines whether the difference between the phase voltage V _dc and the arithmetic applied voltage V _dc ′ exceeds a preset range (eg, a range of ± 5% of the phase voltage V _dc ). In the determining step S19, when the difference is within the predetermined range, it is determined whether the temperature of the storage chamber exceeds a reference temperature, that is, a normal driving temperature of the storage chamber.

As a result of the determination, when the temperature of the storage compartment exceeds the reference temperature, an error message is output to a display unit provided outside the refrigerator 1, and the driving of the refrigerator 1 is stopped (S25).

In addition, when the temperature of the storage chamber does not exceed the reference temperature, step S11 of driving the motor 110 to the initial driving mode is performed.

According to the proposed embodiment, when the refrigerator 1 is driven, when the rotation state of the electric motor 110 of the compressor 10 is sensed and the rotation state is abnormal, that is, when the rotation operation is interfered or constrained, By restarting the motor 110, the abnormal state may be eliminated.

In addition, the abnormal state of the motor 110 is not provided with a separate sensor for detecting the physical state of the rotor, such as a hall sensor, it can be detected by the detected current and voltage, the motor driving device ( The physical configuration of 100) can be simplified, and manufacturing costs can be reduced.

1: refrigerator
10: Body
60: compressor
100: electric motor drive device
110: electric motor
120: control unit
130: inverter
140: converter

Claims (18)

In a refrigerator having a condenser, an evaporator, a compressor and an expansion valve,
A compressor including a compression mechanism for compressing a coolant for supplying cold air to the storage chamber, and a motor including a stator and a rotor rotated with respect to the stator to operate the compression mechanism;
An inverter including a plurality of switching elements, and supplying an output current having an alternating frequency of a predetermined frequency and a predetermined magnitude to the electric motor by a switching operation of the switching element; And
By comparing the magnitude of the arithmetic applied voltage calculated on the basis of the output current, the inductance and the resistance of the motor and the magnitude of the phase voltage applied to the inverter, it is determined whether the rotation of the rotor is interfered or constrained, And a control unit for controlling the inverter to drive the electric motor in a restart mode for eliminating rotation or interference. The method of claim 1,
And the controller determines that the rotation of the rotor is interrupted or constrained when the state where the difference between the phase voltage and the arithmetic applied voltage is within a preset range lasts for a preset time. The method of claim 2,
The preset range is a refrigerator, characterized in that more than 0 to less than 10% of the phase voltage value. The method of claim 1,
The control unit,
A calculator for calculating an arithmetic applied voltage based on the output current output to the motor and an inductance of a coil provided to the motor; And
And a comparator for comparing the arithmetic applied voltage with a phase voltage applied to the inverter. The method of claim 1,
The restart mode is,
A first restart mode of stopping the operation of the electric motor for a first period of time; And
And a second restart mode for stopping the operation of the electric motor for a second period when the first restart mode is repeatedly performed a predetermined number of times. The method of claim 5, wherein
And the first restart mode counts the number of times that the difference between the phase voltage and the arithmetic applied voltage is within the predetermined range, and is performed when the number of times is a predetermined number or more. The method of claim 5, wherein
And the first restart mode and the second restart mode stop the operation of the motor for the first period and the second period, respectively, and then operate the motor. The method of claim 7, wherein
And the second period is greater than the first period. The method of claim 1,
The control unit,
An estimator for estimating estimated position information of the rotor with respect to the stator of the motor, based on the output current input to the motor;
A current command generation unit that generates a current command value based on the estimated position information and the speed command;
A voltage command generator for generating a voltage command value based on the current command value and the output current; And
And a switching control signal output unit configured to generate the inverter switching control signal based on the voltage command value and output the generated inverter switching control signal to the inverter. A compressor for compressing a coolant for supplying cold air to the storage chamber, a motor having a stator and a rotor which rotates with respect to the stator, the inverter for supplying output current to the motor, and the inverter; In the refrigerator comprising a control unit,
Controlling the inverter to drive the electric motor in an initial driving mode;
Comparing the magnitude of an arithmetic applied voltage calculated based on the output current, the inductance and the resistance of the motor, and the magnitude of the phase voltage applied to the inverter to determine whether the rotation of the rotor is interfered or constrained;
Controlling the inverter to drive the electric motor in a restart mode when the rotation of the rotor is interrupted or constrained; And
And controlling, by the controller, the inverter according to a speed command and the output current. The method of claim 10,
The determining of whether the rotation of the rotor is interfered with or restrained may include: when the control unit maintains a state in which a difference between the phase voltage and the arithmetic applied voltage is within a preset range for a predetermined time, The control method of the refrigerator, characterized in that the rotational drive of the judged to be an interference state or a restrained state. The method of claim 11,
The preset range is a control method of the refrigerator, characterized in that the range of 0 or more and 10% or less of the phase voltage value. The method of claim 11,
The controlling of the inverter to drive the motor in the restart mode, the control unit,
Performing, by the control unit, a first restart mode for stopping the operation of the electric motor for a first period of time; And
Performing a second restart mode in which the controller counts the number of times the first restart mode is performed and stops the operation of the motor for a second period when the first restart mode is repeatedly performed a predetermined number of times; Control method of the refrigerator comprising a. The method of claim 13,
The performing of the first restart mode may be performed when the difference between the phase voltage and the arithmetic applied voltage is counted within the predetermined range, and the number of times is greater than or equal to a predetermined number of times. Control method. The method of claim 14,
The step of performing the first restart mode or the step of performing the second restart mode,
And initializing the number of times that the difference between the counted phase voltage and the arithmetic applied voltage is within the predetermined range or the number of times the first restart mode is performed. The method of claim 10,
In the initial driving mode, the control unit supplies a DC current of a predetermined magnitude to the motor so that the rotor of the motor is aligned in an initial state, and rotates the rotor at a constant speed regardless of the speed command. The control method of the refrigerator characterized in that. The method of claim 10,
The controlling of the inverter supplying the output current to the motor according to the speed command and the output current input to the motor,
Estimating by the control unit estimating the position of the rotor of the electric motor based on the output current and the speed command; And
And controlling, by the controller, the inverter based on the estimated position of the rotor and the speed command. The method of claim 10,
The output current formed of at least three or more phases is input to the electric motor, and the output current of one phase overlaps with the output current of the other phase in at least a portion of the refrigerator.

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