KR20050013943A - Motor driving device and cooling fan driving device in refrigerator - Google Patents

Abstract

PURPOSE: A motor driving device and a cooling fan driving device of a refrigerator are provided to cool down the temperature of a cavity by increasing the flow of refrigerant by regulating rotational speed of a motor according to the change ratio of currents of a q-axis. CONSTITUTION: A motor driving device of a refrigerator for comprising a compressor rotated by a three-phase motor(3A), a condenser, and a cooling cycle having a cooler, and cooling down the inside of a refrigerator compartment and the cooler by compressing refrigerant is composed of an inverter circuit(42) for supplying three-phase driving currents to a stator coil of the motor; a PWM(Pulse Width Modulation) circuit supplying a PWM signal to the inverter circuit; a driving current sensing unit for detecting the three-phase driving current; a d-q converting unit(52) for converting into a d-axis current(Id) of a current component corresponding to magnetic flux and a q-axis current(Iq) of a current component corresponding to torque of the motor based on the three-phase driving current; a rotational speed sensing unit for detecting the rotational speed of the motor; a control unit outputting a speed order signal based on the converted q-axis current; and a speed control unit outputting a control signal to the PWM circuit to be the rotational speed correspondent to the speed order signal based on the detected present rotational speed and the speed order signal. The control unit controls the speed order signal corresponding to the change ratio of the q-axis current and the temperature of a cavity of a refrigerator compartment by regulating the flow of refrigerant flowing through the cooling cycle.

Description

Motor Drive and Cooling Fan Drive in Refrigerator {MOTOR DRIVING DEVICE AND COOLING FAN DRIVING DEVICE IN REFRIGERATOR}

The present invention relates to a refrigerator having a cooler.

Conventionally, the control of the internal temperature of the refrigerator compartment or freezer compartment in a refrigerator is provided with a temperature sensor in each room, and the motor which rotates a compressor is controlled so that the temperature detected by this temperature sensor may become a predetermined temperature range ( Patent Document 1).

By the way, the drive method using vector control is known as a motor control method, and the washing machine using the drive method by this vector control is proposed (patent document 2).

[Patent Document 1]

Japanese Patent Laid-Open No. 11-304332

[Patent Document 2]

Japanese Patent Laid-Open No. 2003-24686

As described above, in the conventional refrigerator, since the control of the temperature inside the high temperature by the temperature sensor is used, it is difficult to grasp the temperature of the whole temperature inside the high temperature, and since there is a heat capacity of a protective part such as a temperature sensor cover, the temperature inside the high temperature There is a problem that can not react immediately even if is raised.

Since the control is performed by the temperature sensor, the load of the refrigeration cycle itself is unclear, and the compressor may be excessively driven to impose a refrigeration cycle. In this case, since the load is lightly controlled by checking the safety factor, there is a problem that proper control cannot be performed.

If food is placed before the temperature sensor, there is a problem that the sensor temperature is hard to change and it is not possible to know whether food is newly introduced into the chamber.

In addition, it is not possible to detect the blockage of the duct through which the cold air blown by the cooling fan flows, or the state that it is difficult to cool down if the food is placed before the outlet of the cold air.

In addition, since the amount of implantation of the cooler cannot be grasped, there is a problem that the power consumption is consumed even though the refrigeration cycle is forcibly moved and the cooling performance is not improved.

In addition, there is a problem that how to control the internal temperature of the refrigerator in the case of using vector control has not been proposed at all.

Accordingly, the present invention proposes a motor drive device and a cooling fan drive device of a refrigerator that control a temperature inside a refrigerator using vector control in view of the above problems.

The invention of claim 1 includes a refrigerating cycle having a compressor rotating with a three-phase motor, a condenser, and a cooler, wherein the compressor compresses a refrigerant to cool the cooler, and cools the inside of the cooling chamber. A drive device, comprising: an inverter circuit for supplying a drive current of three phases to a stator coil of the motor, a PWM circuit for supplying a PWM signal to the inverter circuit, drive current detection means for detecting the drive current of the three phases, and the detection A dq converting means for converting the d-axis current, which is a current component corresponding to the magnetic flux, and the q-axis current, which is a current component corresponding to the torque of the motor, based on the three-phase drive current; Rotation speed detection means, control means for outputting a speed command signal based on the converted q-axis current, the detected current rotation speed and the speed And a speed control means for outputting a control signal to the PWM circuit so as to be a rotation speed corresponding to the speed command signal, based on the command signal, wherein the control means corresponds to the speed command in response to a change rate of the q-axis current. It is a motor drive device of a refrigerator, characterized in that the signal is controlled, and the flow rate of the refrigerant flowing through the refrigeration cycle is adjusted to control the internal temperature of the cooling chamber.

The invention according to claim 2 is the motor driving apparatus of the refrigerator according to claim 1, wherein the control means outputs a speed command signal so that the rotation speed increases when the change rate of the q-axis current is positive.

The invention according to claim 3, wherein the control means outputs the speed command signal so that the rotational speed of the change rate is lowered when the change rate of the q-axis current is negative. .

The refrigerator according to claim 4, wherein the refrigerator has a cooling fan in the vicinity of the cooler, and the control means changes the rotation speed of the cooling fan based on the q-axis current. .

The refrigerator according to claim 5, wherein the refrigerator has door detecting means for detecting opening and closing of the cooling chamber door, and the control means controls the internal temperature of the refrigerator after the door detecting means detects a door closed state. It is a motor drive apparatus of the refrigerator of Claim 1.

The refrigerator according to claim 6, wherein the refrigerator has door detecting means for detecting opening and closing of the door of the cooling chamber, and the control means is configured to maintain the temperature inside the refrigerator from a predetermined time after the door detecting means detects the door closed state. It is a motor drive apparatus of the refrigerator of Claim 1 characterized by performing control.

According to a seventh aspect of the present invention, the control means obtains instantaneous electric power based on the q-axis current, and displays the instantaneous power on the display means.

The invention according to claim 8 is the motor drive device for a refrigerator according to claim 1, wherein the rotational speed detection unit calculates from the three-phase drive current detected by the drive current detection unit.

According to a ninth aspect of the present invention, the rotation speed detecting means calculates the position based on a position signal from a position detecting means provided in the vicinity of the motor rotor.

The motor of the refrigerator according to at least one of claims 1 to 9 is characterized in that the motor is a three-phase induction motor or a three-phase brushless direct current motor.

The invention according to claim 11 comprises a refrigeration cycle having a compressor rotating with a three-phase motor, a condenser and at least a cooler, and arranged in the vicinity of the cooler to blow cool air cooled in the cooler to a cooling chamber. A cooling fan drive device of a refrigerator having: an inverter circuit for supplying three-phase driving current to a stator coil of a fan motor for rotating the cooling fan, a PWM circuit for supplying a PWM signal to the inverter circuit, and the three-phase driving current Drive current detection means for detecting a signal, dq current which is a current component corresponding to a magnetic flux and qq current which is a current component corresponding to torque of the fan motor based on the detected three-phase drive current. A converting means, a rotating speed detecting means for detecting the rotating speed of the fan motor, and a speed command signal based on the converted q-axis current; Means and a speed control means for outputting a control signal to the PWM circuit so as to be a rotation speed corresponding to the speed command signal based on the detected current rotation speed and the speed command signal, wherein the control means includes: The cooling fan drive apparatus of the refrigerator characterized by controlling the said speed command signal corresponding to the change rate of the said q-axis current, and controlling the temperature in the inside of the said cooling chamber by adjusting the flow volume of the cold air conveyed by the said cooling fan.

According to a twelfth aspect of the present invention, there is provided a cooling fan drive device according to claim 11, wherein the speed command signal is output so that the rotation speed increases when the change rate of the q-axis current is positive.

According to a thirteenth aspect of the present invention, the control means outputs the speed command signal so that the rotational speed of the change rate decreases when the change rate of the q-axis current is negative. Device.

The refrigerator according to claim 14, wherein the refrigerator has door detecting means for detecting opening and closing of the door of the cooling chamber, and the control means controls the inside temperature of the refrigerator after the door detecting means detects a door closed state. It is a cooling fan drive apparatus of the refrigerator of Claim 11.

The invention according to claim 15 is the cooling fan drive device for a refrigerator according to claim 11, wherein the control means judges that the cooler has an idea when the converted q-axis current reaches a predetermined value.

16. The invention according to claim 16, wherein the control means further comprises: the cooling fan when the converted q-axis current rises above a predetermined value or when the rotation speed detected by the rotation speed detection means falls below a predetermined rotation speed. It is judged that it is locked, The cooling fan drive apparatus of the refrigerator of Claim 11 characterized by the above-mentioned.

According to a seventeenth aspect of the present invention, the control means forcibly rotates the cooling fan when the cooling fan is stopped while controlling the internal temperature of the cooling chamber. The cooling fan according to claim 11, wherein the cooling fan is forcibly rotated. It is a driving device.

The invention according to claim 18 is the cooling fan drive device for a refrigerator according to claim 11, wherein the rotational speed detecting unit calculates from the three-phase driving current detected by the driving current detecting unit.

The invention according to claim 19, wherein the rotational speed detecting means calculates based on a position signal from a position detecting means provided in the vicinity of the fan motor rotor, wherein the cooling fan drive device according to claim 11 to be.

The invention according to claim 20 is a cooling fan drive device for a refrigerator according to at least one of claims 11 to 19, wherein the fan motor is a three-phase induction motor or a three-phase brushless direct current fan motor.

1 is a block diagram of a refrigerator in one embodiment of the present invention;

Fig. 2 is a vector diagram for changing αβ from three phases.

Fig. 3 is a vector diagram for changing dq from αβ.

4 is a time chart showing the relationship between the temperature of the cooler, the temperature within the refrigerator, the q-axis current, and time;

5 is a longitudinal sectional view of the refrigerator of the present embodiment;

6 is a configuration diagram of a refrigeration cycle of the present embodiment.

Figure 7 is a block diagram of a refrigerator of one embodiment of the present invention.

Fig. 8 is a graph showing the relationship between the q-axis current and the rotational speed of the fan motor in another embodiment of the lock detection method of the fan motor.

<Explanation of symbols for the main parts of the drawings>

1A: Compression Drive

1B: Fan Drive

2: subject fisherman

3A, 5B: Compression Motor

3B, 5A: Fan Motor

4A: Fan Drive

10: refrigerator

14: refrigerator

16: vegetable room

18: first freezer

20: second freezer

22: cooler

24: cooling fan

28: compressor

30: refrigeration cycle

42: inverter circuit

48A, 48B, 68A, 68B: PWM forming part

52: dq converter

58A, 58B, 66A, 66B: Speed PI Control

64: three-phase converter

The operation state of the motor drive device of the refrigerator according to claim 1 will be described.

The compressor is rotated by a motor to supply a coolant to the cooler to cool the cooler. At this time, when the door of the refrigerator is opened and food is stored, the temperature in the refrigerator is raised. When the temperature inside the refrigerator rises, the ambient temperature of the cooler also rises, increasing the amount of evaporation of the refrigerant flowing through the cooler. This raises the load on the compressor.

On the other hand, since the motor for rotating the compressor is controlled to rotate at a constant speed from the control unit of the refrigerator, the driving current increases when the load of the compressor increases.

The dq converting means converts the detected drive current into a d-axis current which is a current component corresponding to the magnetic flux and a q-axis current which is a current component corresponding to the torque of the motor.

When the q-axis current is input to the control means, the control means outputs a speed command signal corresponding to the rate of change of the q-axis current.

The speed control means outputs a control signal to the PWM circuit based on the current rotation speed of the motor detected by the rotation speed detection means and the rotation speed corresponding to the speed command signal based on the speed command signal from the control means. .

In the PWM circuit, the inverter circuit is controlled by supplying a PWM signal to the inverter circuit in response to the control signal.

In the inverter circuit, the drive current of the three phases is output to the stator coils of the three phases of the motor based on the PWM signal.

As a result, the control means can control the speed command signal corresponding to the rate of change of the q-axis current, control the rotational speed of the compressor, and adjust the flow rate of the refrigerant flowing through the refrigeration cycle.

As a result, when food is introduced into the refrigerator compartment, the temperature in the refrigerator is raised, and accordingly, the load on the compressor is also raised, thereby increasing the q-axis current. By adjusting the rotational speed of the motor in response to the increased rate of q-axis current, the refrigerant flow rate is increased to cool the internal temperature. Therefore, the internal temperature of the cooling chamber can be controlled without using a temperature sensor.

In the motor driving apparatus of the refrigerator of claim 2, when the control means has a positive rate of change in q-axis current, the control means determines that food is put into the refrigerator, and outputs a speed command signal so that the rotational speed is increased.

In the motor driving apparatus of the refrigerator of claim 3, when the change rate of the q-axis current is negative, the control means judges that the food in the refrigerator is sufficiently cooled and the food temperature is lowered, and outputs a speed command signal so that the rotational speed is lowered. .

In the motor driving apparatus of the refrigerator of claim 4, the control means controls the rotation speed of the cooling fan in accordance with the food put into the refrigerator by changing the rotation speed of the cooling fan based on the q-axis current.

In the motor drive apparatus of the refrigerator of claim 5, the control means controls the internal temperature of the refrigerator when the door detects the closed state. This is because when the door is closed after the door is opened, food is introduced into the refrigerator and the temperature in the refrigerator is high.

In the motor drive apparatus of the refrigerator of claim 6, the control means controls the internal temperature of the refrigerator from a predetermined time after the door closing state is detected. This is not limited to the case where food is necessarily fed even when the door is closed after being opened. Therefore, if food is added, the temperature inside the refrigerator is raised after a predetermined time elapses. If food is not fed, the temperature in the refrigerator is maintained. Therefore, the temperature in the refrigerator is controlled after the predetermined time has elapsed to perform the judgment.

In the motor driving apparatus of the refrigerator of claim 7, the control means obtains the instantaneous power on the basis of the q-axis current and displays the instantaneous power on the display means, thereby indicating the current instantaneous power to the user.

In the motor drive device of the refrigerator of claim 8, by calculating the rotational speed from the drive current detected by the drive current detection means, a motor drive device without a sensor can be realized and the cost can be reduced.

In the motor drive device of the refrigerator of claim 9, since the rotational speed is detected based on the position signal from the position detecting means provided in the vicinity of the motor rotor, the accurate rotational speed can be detected.

In the motor driving apparatus of the refrigerator of claim 10, the motor can be driven accurately and reliably by using a three-phase induction motor or a three-phase brushless direct current motor.

The operation state of the cooling fan drive device of the refrigerator according to claim 11 will be described.

The cooling fan is rotated by a fan motor to blow cold air into the cooling chamber. At this time, the door of the refrigerator is opened to accommodate food. The amount of stored food changes the flow of cold air, thereby increasing or decreasing the motor load. Since the fan motor is controlled to rotate at a constant speed from the control unit of the refrigerator, the driving current changes in response to the above-described change in the motor load.

The dq converting means converts the detected drive current into a d-axis current which is a current component corresponding to the magnetic flux and a q-axis current which is a current component corresponding to the torque of the fan motor.

When the q-axis current is input to the control means, the control means outputs a speed command signal corresponding to the rate of change of the q-axis current.

The speed control means outputs a control signal to the PWM circuit so as to become a rotation speed corresponding to the speed command signal based on the current rotation speed of the fan motor detected by the rotation speed detection means and the speed command signal from the control means. .

In the PWM circuit, the inverter circuit is controlled by supplying a PWM signal to the inverter circuit in response to the control signal.

In the inverter circuit, the drive current of the three phases is output to the stator coils of the three phases of the fan motor based on the PWM signal.

As a result, when food is introduced into the cooling chamber, the flow of cold air is deteriorated, and the load of the cooling fan is also increased, thereby increasing the q-axis current. By increasing the rotational speed of the fan motor in response to the increased rate of change of the q-axis current, the refrigerant flow rate is increased to cool the internal temperature. Therefore, the internal temperature of the cooling chamber can be controlled without using a temperature sensor.

In the drive device for the fan motor of the refrigerator according to claim 12, the control means judges that when the change rate of the q-axis current is positive, it is because food is introduced into the refrigerator and cold air is difficult to flow, so that the rotational speed is increased. Output the signal.

In the fan motor driving apparatus of the refrigerator of claim 13, when the change rate of the q-axis current is negative, the control means judges that the amount of food in the refrigerator is reduced and that the cold air easily flows, so that the speed command signal is lowered. Outputs

In the fan motor drive device of the refrigerator of claim 14, the control means controls the internal temperature of the refrigerator when the door detects the closed state. This is because when the door is closed after the door is opened, food is introduced into the refrigerator and the temperature in the refrigerator is high.

In the cooling fan drive device of the refrigerator of claim 15, the control means detects the idea of the cooler when the converted q-axis current reaches a predetermined value. For example, when the cooling fan is located on the downstream side of the cooler while paying attention to the flow of cold air, if the cooler is implanted, the flow of cold air is deteriorated, the air pressure around the cooling fan is lowered, and the load of the fan motor is lowered q The shaft current also drops. Therefore, when this q-axis current value falls below a predetermined value, it is judged that there was an idea. In addition, in the case where the cooling fan is located upstream of the cooler in consideration of the flow of cold air, if the cooler is implanted, the flow of cold air is deteriorated, the air pressure around the cooling fan is increased, and the load of the fan motor is increased so that the q-axis current is also increased. Going up Therefore, when this q-axis current value raises more than predetermined value, it determines with an idea.

In the cooling fan drive device of the refrigerator of claim 16, the control means cools when the converted q-axis current rises above a predetermined value, or when the rotation speed detected by the rotation speed detection means becomes a predetermined rotation speed or less. It is determined that the fan is locked. Thereby, the locked state of a cooling fan can be detected reliably.

In the cooling fan drive device of the refrigerator of claim 17, when the cooling means is stopped when the control means controls the internal temperature of the cooling chamber, the cooling fan is forcibly rotated. In the case of performing the internal temperature control of claim 1, since the control cannot be performed unless the cooling fan is rotated, the cooling fan is forcibly rotated.

In the cooling fan drive device of the refrigerator of claim 18, by calculating the rotational speed from the drive current detected by the drive current detection means, a cooling fan drive device without a sensor can be realized and the cost can be reduced.

In the cooling fan drive device of the refrigerator of claim 19, since the rotation speed is detected based on the position signal from the position detection means provided in the vicinity of the fan motor rotor, the accurate rotation speed can be detected.

In the cooling fan drive device of the refrigerator of claim 20, the fan motor can be driven accurately and reliably by using a three-phase induction motor or a three-phase brushless direct current fan motor.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, the refrigerator 10 of one Embodiment of this invention is demonstrated based on FIG.

1) structure of the refrigerator 10

The structure of the refrigerator 10 is demonstrated based on FIG.

As shown in Fig. 5, the cabinet 12 of the refrigerator 10 is provided with a refrigerator compartment 14, a vegetable compartment 16, a first freezer compartment 18, and a second freezer compartment 20 in order from the top. Doors 14a to 20a are provided in the room.

On the back of the refrigerating chamber 14, the main control part 2 of the refrigerator 10 which consists of microcomputers is provided.

The cooler 22 is provided in the back surface of the 1st refrigerator compartment 18, and the cooling fan 24 is provided above this cooler 22. As shown in FIG.

The back of the second freezing chamber 20 is provided with a machine room 26, and the machine room 26 is provided with a compressor 28.

2) Configuration of the refrigeration cycle 30

The structure of the refrigeration cycle 30 is demonstrated based on FIG.

The refrigerant conveyed from the compressor 28 passes through the condenser 32 to the capillary tube 34.

The refrigerant exiting the capillary tube 34 is evaporated in the cooler 22 and circulated to the compressor 28.

The air cooled by the cooler 22 is blown by the cooling fan 24, and blown into each of the rooms 14 to 20 of the refrigerator 10.

The blown cold air circulates in the refrigerator and is circulated again in the cooler 22.

3) Structure of the electric system of the refrigerator 10

The structure of the electric system of the refrigerator 10 is demonstrated based on the block diagram of FIG.

As shown in Fig. 1, a compression motor 3A for driving the compressor 28, a compression drive device 1A for driving the compression motor 3A, and a main control for controlling the compression drive device 1A. It is comprised by the part (2). In addition, a fan drive device 4A for driving the fan motor 5A of the cooling fan 24 is connected to the compression drive device 1A. Moreover, the door switch 14b, 16b, 18b, 20b provided in the door 14a-20a of each room 14-20 is connected to the main control part 2. As shown in FIG.

First, the structure of the compression drive apparatus 1A is demonstrated.

The compression drive device 1A includes an inverter circuit 42, a rectifier circuit 44, an AC power supply 46, a PWM forming unit 48A, an AD converter 50, and a dq converter 52. And the speed detector 54, the speed command output unit 56, the speed PI controller 58A, the q-axis current PI controller 60, the d-axis current PI controller 62, and the three-phase converter. It consists of 64.

The compression motor 3A which rotates the compressor 28 is a three-phase brushless DC motor. The inverter circuit 42 causes the drive current to flow in three phases through the stator coils 40u, 40v, and 40w of the three phases (u phase, v phase, w phase) of the compression motor 3A.

The inverter circuit 42 is composed of transistors Tr1 to Tr6 which are six power switching semiconductors. Although not shown in the figure, diodes are connected in reverse with respect to these switching transistors Tr1 to Tr6 in parallel. In addition, a detection resistor R1 for detecting a drive current in series with the switching transistors T1 and Tr4 is connected, a detection resistor R2 is connected in series with the switching transistors Tr2 and Tr5, and the switching transistor Tr3 is connected. And a detection resistor R3 are connected in series with Tr6.

The rectifier circuit 44 receives an AC voltage from an AC power supply 46 which is a commercial power supply (AC100V), rectifies it, and supplies it to the inverter circuit 42.

The PWM forming unit 48A supplies a PWM signal to the gate terminals of the six switching transistors Tr1 to Tr6. The PWM forming unit 48A performs pulse width modulation based on the voltages Vu, Vv, and Vw of the three phases described below, and turns on / off each of the switching transistors Tr1 to Tr6 at a predetermined timing. / OFF).

The AD converter 50 detects the voltage value in the detection resistors R1, R2, and R3, converts the voltage value of each phase from an analog value to a digital value, and outputs three phase drive currents Iu, Iv, and Iw. .

The dq converting unit 52 converts the drive currents Iu, Iv, and Iw output from the AD converting unit 50 into the d-axis current Id which is a current component corresponding to the magnetic flux and the torque of the compression motor 3. It converts into q-axis current Iq which is a corresponding current component.

This conversion method converts three phases Iu, Iv, and Iw into two phases Iα and Iβ, as shown in equation (1). 2 is a vector diagram showing the relationship between the three-phase current and the two-phase current.

[Equation 1]

Next, the two-phase currents Iα and Iβ converted in this manner are converted to the q-axis current Iq and the d-axis current Id by using Equation (2). The relationship between the two-phase drive current, q-axis current Iq, and d-axis current Id has the same relationship as the vector diagram shown in FIG.

[Equation 2]

The speed detector 54 detects the rotation angle θ and the rotation speed ω of the compression motor 3A based on the q-axis current Iq and the d-axis current Id. Based on the q-axis current and the d-axis current, the rotation angle θ which is the position of the rotor of the compression motor 3A is obtained, and the rotation speed ω is obtained by differentiating this θ.

The main control unit 2 outputs the speed command signal S based on the q-axis current Iq transferred from the dq converter 52. This control method is described next.

The speed command output unit 56 outputs a reference rotation speed ω ref based on the speed command signal S from the main control unit 2 and the rotation speed ω from the speed detection unit 54. The reference rotation speed ω ref is input to the speed PI control unit 58A together with the current rotation speed ω.

The speed PI control unit 58A outputs the reference P-axis current Iqref and the reference d-axis current Iqref, and the q-axis current PI control unit like the current q-axis current Iq and the current d-axis current Id. Output to 60 and d-axis current PI control part 62. FIG.

The q-axis current PI control unit 60 performs the PI control and performs current / voltage conversion to output the q-axis voltage Vq.

The d-axis current PI control unit 62 performs PI control and simultaneously performs current / voltage conversion to output the d-axis voltage Vd.

In the three-phase converter 64, the d-axis voltage Vd and the q-axis voltage Vq are first converted to the above-described voltage based on the equation (3).

[Equation 3]

The converted abnormal voltages Vα and Vβ are converted into three-phase voltages Vu, Vv and Vw based on the equation (4).

[Equation 4]

The converted three-phase voltages Vu, Vv, and Vw are outputted to the PWM forming unit 48A.

According to the compression drive device 1A described above, the rotational speed is detected based on the d-axis current Id and the q-axis current Iq, and this rotational speed ω and the speed command signal S from the main control unit are provided. The control is performed on the basis of the above, and the PWM signal is output from the PWM forming section 48A to the inverter circuit 42 so that the compression motor 3 is rotated at the rotational speed? Ref in accordance with the speed command signal S. The inverter circuit 42 outputs the three-phase drive current to the three-phase stator winding 40 of the compression motor 3A based on this.

The fan drive device 4A of the fan motor 5A is composed of a speed PI control unit 66A, a PWM forming unit 68A, and a drive circuit 70.

The reference rotational speed? Ref from the speed command output section 56 is input to the fan drive device 4A, and the rotation of the cooling fan 24 is controlled based on this. The fan motor 5A is a three-phase brushless DC motor.

The fan drive device 4A, similarly to the compression drive device 1A, drives the PWM signal formed by the speed PI control unit 66A and the PWM forming unit 68A based on the reference rotational speed? Ref. The rotational speed is controlled by outputting the three-phase driving current to the fan motor 5A.

4) First control method of high internal temperature

The refrigerator 10 of the said structure WHEREIN: The 1st control method which adjusts temperature inside a refrigerator is demonstrated.

In the refrigerator 10 having the above-described configuration, when food is stored in at least one of the refrigerating chamber 14, the vegetable chamber 16, the first freezing chamber 18, and the second freezing chamber 20, the food has heat. The temperature in the refrigerator is raised by the capacity. By doing so, the temperature of the air returning through the inside of the refrigerator 22 to the cooler 22 is increased to increase the amount of refrigerant evaporating from the cooler 22, and the load on the refrigeration cycle 30, that is, the compressor 28 is increased. Is increased.

In this case, since the rotation speed of the compression motor 3A is controlled to be maintained at a constant number by the speed command signal S from the main control unit 2 of the refrigerator 10, it is applied to the compression motor 3A. Torque is increased.

As the torque increases, the q-axis current Iq also increases.

As a result, when the temperature in the refrigerator continues to increase due to the heat capacity of the food, the q-axis current Iq also increases due to the increase in the load on the refrigeration cycle 30.

Since the amount of change in the q-axis current Iq is proportional to the heat capacity of the food put into the refrigerator, the slope of the q-axis current Iq output from the dq converter is calculated by the main controller 2, and the slope (per unit time) is calculated. Main controller 2 controls the speed command signal S, and the rotation speed of the compression motor 3A and the cooling fan 24 increases.

As a result, when food is introduced, the rotation speed of the compression motor 3A and the cooling fan 24 is increased accordingly, and thus the capacity of the refrigeration cycle 30 is increased. The temperature is held at a constant temperature.

On the other hand, when time passes after the food is fed, the injected food is cooled to lower the internal temperature, and the q-axis current Iq is also lowered when the load on the refrigeration cycle 30, that is, the compressor 28 is reduced. Thus, the main controller 2 calculates the reduction rate per unit time of the q-axis current Iq, and outputs the speed command signal S such that the rotation speed of the compression motor 3A and the cooling fan 24 drops accordingly. As a result, when the temperature of the injected food is lowered, the capacity of the compressor 28 is lowered, and the temperature in the refrigerator is not lowered below the predetermined temperature range.

5) Second Control Method of High Temperature

Instead of the first control method described above, a second control method of the internal temperature of the refrigerator will be described.

In the first control method, after the food is fed and the temperature in the refrigerator is raised, the rate of change by the q-axis current Iq is calculated and controlled. In this second control method, as shown in FIG. When the doors 14a to 20a of 20 are opened and then closed, control is performed based on timing.

Specifically, when food is introduced, at least one of the rooms 14 to 20 (for example, the door 14a of the refrigerating compartment) is always opened and then closed. Therefore, from the time the door 14a detects the state in which the door 14a is closed, the main control part 2 starts detecting the rate of change of the q-axis current Iq.

As shown in FIG. 4, when the internal temperature of the refrigerator is increased by the heat capacity of the food stored therein and the q-axis current Iq is also increased, the main control unit 2 determines the slope of the q-axis current Iq. The speed command signal S is output so as to increase the rotation speed of the compression motor 3A and the cooling fan 24 in accordance with the increase amount of the change rate per unit time.

As a result, the timing at which the food is added can be detected accurately, thereby easily controlling the internal temperature. For example, even when the door is opened or closed, when the food is not fed, the internal temperature of the refrigerator is increased slightly, and the q-axis current Iq does not increase, and there is no need to control the internal temperature. On the other hand, when food having a large heat capacity such as a heat substance or the like or a food having a normal temperature is added, the internal temperature of the refrigerator is raised, so it is necessary to perform the aforementioned control method. And the timing of whether this control is performed can be performed correctly and reliably by the signal of the door switch 14b-20b.

6) Third control method of high temperature

Next, a third control method of the internal temperature of the refrigerator 10 will be described.

In the second control method, the q-axis current Iq was detected from the time when the door was closed, but in the third control method, the q-axis current Iq after t0 was detected after a predetermined time after the door was closed.

That is, immediately after the food with heat capacity is put in, it is unclear whether the temperature in the refrigerator is increased due to the opening of the door or the temperature in the refrigerator is increased by the food. Therefore, the main controller 2 measures the rate of change of the q-axis current Iq after t0 after a predetermined time after the door is closed.

For example, if the door is simply opened or closed or a small heat capacity food is put in, the q-axis current Iq after a predetermined time t0 after the door is closed is raised once but the rate of decrease thereafter becomes large. In other words, immediately after the door is closed, the q-axis current Iq also increases due to the influence of opening and closing of the door, but if only the door is opened or a food having a small heat capacity is put in, the increased q-axis current Iq The reduction rate is large. In the case where the reduction ratio is large, the main controller 2 determines that there is little load and maintains the rotational speed, or outputs the speed command signal S so as to increase the small rotational speed even when the rotational speed is increased.

On the other hand, if food with a large heat capacity is introduced, it may be considered that the decrease rate of the q-axis current Iq after t0 after a predetermined time is small or increases further without decreasing. Therefore, when the reduction rate of the q-axis current Iq after t0 after a predetermined time is small and when it is increased, it is judged that a large load of food is put in, so that the rotation speed of the compression motor 3A and the cooling fan 24 is increased. Outputs the speed command signal S.

7) fourth control method of high temperature

In the third control method, the speed command signal S is output at the rate of change of the q-axis current Iq after a predetermined time t0 from the time when the door is closed, but in this fourth control method, after the door is closed, After recording the maximum value of q-axis current Iq, it is determined whether the reduction rate is large or small.

When the rate of change of the q-axis current Iq after measuring the maximum value is measured, if the reduction rate after the maximum value is large, only a small load or opening or closing of the door is judged. The rotation speed of one compression motor 3A and the cooling fan 24 can be controlled by the speed command signal S. FIG.

Moreover, the case where a large load of food is thrown in and the value of q-axis current Iq continuously increases without measuring the maximum value of q-axis current Iq is considered. In this case, when the maximum value is not measured even after the predetermined time t1 has elapsed, it is determined that the q-axis current Iq continues to increase so that the compression motor 3A and the cooling fan 24 rotate at the maximum rotational speed. Outputs the speed command signal S.

8) Fifth Control Method of High Temperature

In the fifth control method, the time that the door has been opened is calculated by the door open / close signal detected by the door switches 14b to 20b. At the same time, the increase in torque accompanying the increase in the load of the refrigeration cycle 30 after the door is closed is detected by the q-axis current Iq. The rotation speed of the compressor 28 and the cooling fan 24 is controlled to maintain the high internal temperature by the change of the door opening time and the q-axis current Iq.

Specifically, the more the time the door is open and the more the increase rate of the q-axis current Iq, the more the rotation speed is controlled.

9) Change example

In each of the control methods described above, the q-axis current Iq was used only for the control of the internal temperature. However, in addition thereto, a liquid crystal display capable of digital display is connected to the main controller 2, where q is the torque component of the compression motor 3A. By the axial current Iq, the instantaneous power consumed by the compression motor 3A is calculated, and this instantaneous power is displayed by the liquid crystal display device.

This liquid crystal display device is attached to the front surface of the door 14a of the refrigerating chamber 14, for example, so that the user can check the current power consumption of the refrigerator.

<Change example>

The above embodiment is one embodiment of the present invention, and changes can be made without departing from the spirit of the present invention.

(1) Modification Example 1

In the refrigerator 10 of the said embodiment, although there is one cooler, the cooler for a refrigerating compartment and the freezer for a freezer compartment may be provided and you may implement the five control methods demonstrated by the said embodiment in each cooler.

(2) Modification Example 2

Although the compressor motor 3A and the fan motor 5A were three-phase, unbreakable DC motors at the same time, a three-phase induction motor may be substituted instead.

Next, the refrigerator 10 of another embodiment of this invention is demonstrated based on FIGS. 1-3 and 5-8.

1) structure of the refrigerator 10

The structure of the refrigerator 10 is already explained based on FIG.

2) structure of the refrigeration cycle (30)

The structure of the refrigeration cycle 30 is already described with reference to FIG.

3) Structure of the electric system of the refrigerator 10

The structure of the electric system of the refrigerator 10 is demonstrated based on the block diagram of FIG. The same reference numerals as in FIG. 1 denote the same components as those in FIG. 1 and the description thereof will be omitted.

As shown in FIG. 7, the fan motor 3B which drives the cooling fan 24, the cooling fan drive device 1B which drives this fan motor 3B, and this cooling fan drive device 1B are shown. It consists of the main control part 2 to control. In addition, a compression drive device 4B for driving the compression motor 5B of the compressor 28 is connected to the cooling fan drive device 1B. Moreover, the door switch 14b, 16b, 18b, 20b provided in the door 14a-20a of each room 14-20 is connected to the main control part 2, respectively.

First, the structure of the cooling fan drive device 1B will be described.

The cooling fan drive device 1B includes an inverter circuit 42, a rectifier circuit 44, an AC power supply 46, a PWM forming unit 48B, an AD converter 50, and a dq converter 52. ), Speed detection unit 54, speed command output unit 56, speed PI control unit 58B, q-axis current PI control unit 60, d-axis current PI control unit 62, and three-phase conversion It is comprised by the part 64.

The fan motor 3B which rotates the cooling fan 24 is a three-phase brushless DC motor. The inverter circuit 42 causes the drive current to flow in three phases through the stator windings 40u, 40v, and 40w of the three phases (u phase, v phase, w phase) of the fan motor 3B.

The PWM forming unit 48B supplies a PWM signal to the gate terminals of the six switching transistors Tr1 to Tr6. The PWM forming unit 48B performs pulse width modulation on the basis of the voltages Vu, Vv, and Vw described next, and turns on / off each of the switching transistors Tr1 to Tr6 at a predetermined timing.

The AD converter 50 detects the voltage value in the detection resistors R1, R2, and R3, converts the voltage value of each phase from an analog value to a digital value, and outputs three phase drive currents Iu, Iv, and Iw.

The dq converter 52 corresponds to the d-axis current Id as the current component corresponding to the magnet and the torque of the fan motor 3B to the drive currents Iu, Iv, and Iw output from the AD converter 50. It converts into q-axis current Iq which is a current component.

The speed detector 54 detects the rotation angle θ and the rotation speed ω of the fan motor 3B based on the q-axis current Iq and the d-axis current Id. Based on the q-axis current and the d-axis current, the rotation angle θ which is the position of the rotor of the fan motor 3B is obtained, and the rotation speed ω is obtained by differentiating this θ.

The main control unit 2 outputs the speed command signal S based on the q-axis current Iq transferred from the dq converter 52. This control method is described next.

The speed command output unit 56 outputs a reference rotation speed ω ref based on the speed command signal S from the main control unit 2 and the rotation speed ω from the speed detection unit 54. The reference rotation speed ω ref is input to the speed PI control unit 58B like the current rotation speed ω.

The speed PI control unit 58B outputs the reference q-axis current Iqref and the reference d-axis current Idref, and the q-axis current PI control unit like the current q-axis current Iq and the current d-axis current Id. Output to 60 and d-axis current PI control part 62, respectively.

The three-phase converter 64 outputs the converted three-phase voltages Vu, Vv, and Vw to the PWM forming unit 48B.

According to the cooling fan drive device 1B described above, the rotational speed is detected based on the d-axis current Id and the q-axis current Iq, and the rotational speed ω and the speed command from the main controller 2 are obtained. Feedback control is performed on the basis of the signal S, and the inverter circuit 42 converts the PWM signal from the PWM forming portion 48B so that the fan motor 3 is rotated at the rotational speed ω ref in accordance with the speed command signal S. Output to The inverter circuit 42 outputs the drive current of three phases to the stator coil 40 of the three phases of the fan motor 3B based on this.

The compression drive device 4B of the compression motor 5B is composed of a speed PI control unit 66B, a PWM forming unit 68B, and a drive circuit 70.

The reference rotational speed? Ref from the speed command output unit 56 is input to the compression drive device 4B, and the rotation of the compressor 28 is controlled based on this. The compression motor 5B is a three-phase brushless DC motor.

Similarly to the cooling fan drive device 1B, the compression drive device 4B is configured to drive a PWM signal formed by the speed PI control unit 66B and the PWM forming unit 68B based on the reference rotational speed? Ref. The rotational speed is controlled by transferring to 70) and outputting the drive current of three phases to the compression motor 5B.

4) 6th control method of high temperature

In the refrigerator 10 of the said structure, the 6th control method of adjusting temperature inside a refrigerator is demonstrated.

In the refrigerator 10 having the above-described configuration, when food is stored in at least one of the refrigerating chamber 14, the vegetable chamber 16, the first freezing chamber 18, and the second freezing chamber 20, the food is cooled by the food. The flow of deteriorates and the load on the cooling fan 24 which blows cold air increases.

In this case, the torque applied to the fan motor 3B is controlled by the speed command signal S from the main control unit 2 of the refrigerator 10 so that the rotation speed of the fan motor 3B is maintained at a constant number. Is increased.

As the torque increases, the q-axis current Iq also increases.

As described above, when food is stored, the flow of cold air deteriorates, and the q-axis current Iq also increases due to an increase in the load on the cooling fan 24.

Since the amount of change in the q-axis current Iq is proportional to the amount of food put into the refrigerator, the slope of the q-axis current Iq output from the dq converter is calculated by the main controller 2, and the slope (per unit time) is calculated. The main control unit 2 controls the speed command signal S in accordance with the amount of increase), and is controlled so that the rotation speed of the fan motor 3B and the coil motor 5B increases.

As a result, when food is introduced, the rotation speeds of the fan motor 3B and the compression motor 5B are increased to increase the cooling capacity, and the temperature in the refrigerator is kept at a constant temperature by preventing the inside temperature of the refrigerator from being increased. Is retained.

On the other hand, when food is taken out, the flow of cold air improves only as much as taken out, and when the load applied to the cooling fan 24 decreases, the q-axis current Iq also decreases. Thus, the main controller 2 calculates the reduction rate per unit time of the q-axis current Iq and outputs the speed command signal S so that the rotation speeds of the fan motor 3B and the compression motor 5B fall accordingly. As a result, when the food is taken out, the capacity of the cooling fan 24 is also lowered, and the internal temperature of the refrigerator cannot be lowered below the predetermined temperature range.

5) Seventh Control Method of High Temperature

Instead of the sixth control method described above, the seventh control method of the internal temperature of the refrigerator will be described.

In the sixth control method, after the food is fed and the temperature in the refrigerator is raised, the rate of change by the q-axis current Iq is calculated and controlled. In the seventh control method, as shown in Fig. 4, the rooms 14 to 20 are controlled. Is controlled based on the timing when the doors 14a to 20a of the door are opened and then closed.

Specifically, when food is introduced, at least one of the rooms 14 to 20 (for example, the door 14a of the refrigerating compartment) is always opened and then closed. Thus, the door 14a From the time of detecting the closed state with the door switch 14b, the main control part 2 starts detecting the rate of change of the q-axis current Iq.

By this detection, the timing at which the food is put can be detected accurately, and the temperature inside the refrigerator is easily controlled. For example, even when the door is opened or closed, when the food is not fed, the flow of cold air does not change, so that the q-axis current Iq does not increase and there is no need to control the internal temperature. On the other hand, when many foods are put in, the flow of cold air deteriorates and it is necessary to perform the above-mentioned control method. And the timing of whether this control is performed can be performed correctly and reliably by the signal of the door switch 14b-20b.

6) Defrost Control Method

Next, the defrost control method will be described.

The main controller 2 detects the implantation of the cooler 22 when the converted q-axis current reaches a predetermined predetermined value (hereinafter referred to as the implantation reference current value).

As described above, when attention is paid to the flow of cold air, the cooling fan 24 is located downstream of the cooler 22. Therefore, when an ice is generated in the cooler 22, the flow of cold air is deteriorated and the surroundings of the cooling fan 24 are reduced. Air pressure drops, the fan motor 3B is easily rotated and the load is applied to the q-axis current. Therefore, when this q-axis current value falls below the conception reference current amount, it judges that there exists an idea, and defrost control is started.

In the refrigerator 10 of the present embodiment, although the cooling fan 24 is located downstream of the cooler 22, the cooling fan 24 may be located upstream of the cooler in view of the flow of cold air.

In this case, when an frost is generated in the cooler, the flow of cold air is deteriorated, the air pressure around the cooling fan 24 increases, the load of the fan motor increases, and the q-axis current also increases. Therefore, as shown in Fig. 8, when the q-axis current value rises above the ideation reference current value at a predetermined rotational speed, defrosting control is performed after determining that there is an idea.

7) Lock detection method of fan motor 3B

Next, a lock detection method of the fan motor 3B will be described.

The main control unit 2 is configured when the converted q-axis current has risen to a predetermined predetermined value, or if the rotational speed detected by the speed detection unit 54 has become a predetermined rotational speed (for example, the rotational speed is zero) or less. At that time, it is determined that the cooling fan 24 is locked. Thereby, the locked state of the cooling fan 24 can be detected reliably.

8) Other

If the cooling fan 24 is stopped at the time of performing each said control, q-axis current cannot be detected, and the cooling fan 24 is forcibly rotated.

<Change example>

The above embodiment is another embodiment of the present invention, and can be changed without departing from the spirit of the present invention.

(1) Modification Example 1

In the refrigerator 10 of the above embodiment, although there is only one cooler, the cooler and the cooling fan for the refrigerating compartment are respectively provided with the cooler and the cooling fan for the freezer compartment. You may carry out.

(2) Modification Example 2

The fan motor 3B and the fan compression motor 5B were three-phase, unbreakable DC motors at the same time. Alternatively, a three-phase induction motor may be used.

This invention is suitable for control of the internal temperature of the refrigerator in the refrigerator which has a cooler, for example, it is suitable to use for a refrigerator for home use and a refrigerator for business use.

Claims (20)

It is a motor drive apparatus of the refrigerator provided with the compressor which rotates with a three-phase motor, a refrigeration cycle which has a condenser and a cooler, and compresses a refrigerant | coolant by the said compressor, cools the said cooler, and cools the inside of a cooling chamber, An inverter circuit for supplying three-phase driving current to the stator coil of the motor; A PWM circuit for supplying a PWM signal to the inverter circuit; Drive current detection means for detecting drive currents of the three phases; Dq converting means for converting the d-axis current, which is a current component corresponding to the magnetic flux, and the q-axis current, which is a current component corresponding to the torque of the motor, based on the detected three-phase drive current; Rotational speed detection means for detecting a rotational speed of the motor; Control means for outputting a speed command signal on the basis of the converted q-axis current; And a speed control means for outputting a control signal to the PWM circuit so as to become a rotation speed corresponding to the speed command signal based on the detected current rotation speed and the speed command signal, And the control means controls the speed command signal in response to the rate of change of the q-axis current, and controls the internal temperature of the cooling chamber by adjusting the flow rate of the refrigerant flowing through the refrigeration cycle. The motor drive device of a refrigerator according to claim 1, wherein the control means outputs the speed command signal so that the rotation speed increases when the change rate of the q-axis current is positive. The motor driving apparatus of the refrigerator according to claim 1, wherein the control means outputs the speed command signal so that the rotational speed of the change rate decreases when the change rate of the q-axis current is negative. The motor driving apparatus of the refrigerator according to claim 1, wherein the refrigerator has a cooling fan in the vicinity of the cooler, and the control means changes the rotation speed of the cooling fan based on the q-axis current. The refrigerator according to claim 1, wherein the refrigerator has door detecting means for detecting opening and closing of the cooling chamber door, and the control means controls the internal temperature of the refrigerator after the door detecting means detects a door closed state. Motor drive of refrigerator. 2. The refrigerator according to claim 1, wherein the refrigerator has door detection means for detecting opening and closing of the cooling chamber door, and the control means is configured to maintain the temperature inside the refrigerator from a predetermined time after the door detection means detects the door closed state. A motor drive device for a refrigerator, characterized in that for controlling. 2. The motor driving apparatus of a refrigerator according to claim 1, wherein said control means obtains instantaneous power based on said q-axis current and displays it on said display means. The motor drive device of a refrigerator according to claim 1, wherein the rotational speed detection means calculates from a three-phase drive current detected by the drive current detection means. The motor drive device of a refrigerator according to claim 1, wherein said rotational speed detecting means calculates based on a position signal from a position detecting means provided near said motor rotor. 10. The motor driving apparatus of a refrigerator according to any one of claims 1 to 9, wherein the motor is a three-phase induction motor or a three-phase brushless direct current motor. Drive a cooling fan of a refrigerator having a compressor rotating by a three-phase motor, a refrigeration cycle having a condenser and at least a cooler, and disposed near the cooler, and cooling fans cooled by the cooler to a cooling chamber. Device, An inverter circuit for supplying three-phase driving current to a stator coil of a fan motor for rotating the cooling fan; A PWM circuit for supplying a PWM signal to the inverter circuit; Drive current detection means for detecting drive currents of the three phases; Dq converting means for converting the d-axis current, which is a current component corresponding to the magnetic flux, and the q-axis current, which is a current component corresponding to the torque of the fan motor, based on the detected three-phase drive current; Rotational speed detecting means for detecting a rotational speed of the fan motor; Control means for outputting a speed command signal on the basis of the converted q-axis current; A speed control means for outputting a control signal to the PWM circuit so as to be a rotation speed corresponding to the speed command signal based on the detected current rotation speed and the speed command signal, The control means controls the speed command signal in response to the rate of change of the q-axis current, and adjusts the internal temperature of the cooling chamber by adjusting the flow rate of cold air conveyed by the cooling fan. drive. 12. The cooling fan drive device according to claim 11, wherein the control means outputs the speed command signal so that the rotation speed increases when the change rate of the q-axis current is positive. 12. The cooling fan drive device according to claim 11, wherein the control means outputs the speed command signal so that the rotational speed of the change rate decreases when the change rate of the q-axis current is negative. 12. The refrigerator according to claim 11, wherein the refrigerator has door detecting means for detecting opening and closing of the door of the cooling chamber, and the control means controls the inside temperature of the refrigerator after the door detecting means detects a door closed state. Cooling fan drive of the refrigerator. 12. The cooling fan drive device according to claim 11, wherein the control means judges that the cooler is implanted when the converted q-axis current reaches a predetermined value. 12. The cooling means according to claim 11, wherein the control means locks the cooling fan when the converted q-axis current rises above a predetermined value, or when the rotation speed detected by the rotation speed detection means falls below a predetermined rotation speed. Cooling fan drive device of the refrigerator characterized in that it is determined. The cooling fan drive device according to claim 11, wherein the control means forcibly rotates the cooling fan when the cooling fan is stopped when controlling the internal temperature of the cooling chamber. 12. The cooling fan drive device according to claim 11, wherein the rotational speed detecting unit calculates from the three-phase driving current detected by the driving current detecting unit. 12. The cooling fan drive device according to claim 11, wherein the rotational speed detecting unit calculates the position based on a position signal from a position detecting unit provided near the fan motor rotor. 20. The cooling fan drive device according to any one of claims 11 to 19, wherein the fan motor is a three-phase induction motor or a three-phase brushless direct current fan motor.