CN1311214C - Motor driving device for refrigerator and cooling fan driving device - Google Patents

Abstract

The invention provides a refrigerator motor drive device and a cooling fan drive device for vector control of refrigerator temperature. In a refrigerator (10) equipped with a refrigeration cycle (30) of a compressor (28) driven by a three-phase compressor motor (3A), the three-phase drive current output from the inverter circuit (42) to the compressor motor Find the q-axis current (Iq) corresponding to the torque and the d-axis current (Id) corresponding to the magnetic flux. According to the corresponding change between Iq and the temperature in the box, when Iq increases, the motor speed of the compressor is increased correspondingly, and the compression is increased. machine capacity. In a refrigerator (10) equipped with a refrigeration cycle (30) of a cooling fan (24) driven by a three-phase fan motor (3B), the three-phase drive current output from the inverter circuit (42) to the fan motor is obtained by The q-axis current (Iq) corresponding to the torque and the d-axis current (Id) corresponding to the magnetic flux change according to Iq and the flow of cold air. When Iq increases, the fan motor speed increases correspondingly, and the cooling fan capacity increases.

Description

Refrigerator motor drive unit and cooling fan drive unit

technical field

The present invention relates to a refrigerator with a cooler.

Background technique

Conventionally, the indoor temperature control of the refrigerating chamber or freezing chamber of a refrigerator utilizes a temperature sensor installed in each chamber to control a motor that rotates a compressor so that the temperature detected by the temperature sensor is within a predetermined temperature range (Patent Document 1: Japanese Patent Laid-Open Hei. 11-304332).

However, a drive method using vector control is known as a control method of a motor, and it is proposed to adopt such a drive method of vector control in a washing machine (Patent Document 2: Japanese Patent Laid-Open No. 2003-24686).

Contents of the invention

As mentioned above, in the existing refrigerators, because the temperature sensor is used to control the temperature inside the refrigerator, there is a problem that it is difficult to grasp the overall temperature in the refrigerator, and because of the heat capacity of the protection parts such as the protective cover of the temperature sensor, even though the temperature inside the refrigerator has been Rising but no immediate response.

Because it is controlled by a temperature sensor, the load on the refrigerating cycle itself is not known, and sometimes the compressor is forced to be driven to perform the refrigerating cycle. In this case, since the control of the load is lightened for safety, there is another problem that appropriate control cannot be performed.

When food is placed in front of the temperature sensor, the temperature of the sensor changes slowly, and there is a problem that it is not known whether new food is put into the refrigerator.

In addition, if the air passage of the cold air blown by the cooling fan is blocked, or the food is placed in front of the air outlet of the air-conditioner and it is difficult to cool down, the above-mentioned states cannot be detected.

Furthermore, because the degree of frost accumulation on the cooler cannot be grasped, there is a problem that the refrigeration cycle is forced to operate, and although the cooling function does not work, the electric energy is consumed in vain.

Another problem is that in all previous schemes, how to control the temperature in the refrigerator when vector control is adopted is not mentioned.

Therefore, in view of the above problems, the present invention proposes a refrigerator motor driving device and a cooling fan driving device using a vector control method to control the temperature inside the refrigerator.

The first aspect of the present application is a motor drive device for a refrigerator, including a refrigeration cycle with at least a compressor, a condenser, and a cooler that are rotated by a three-phase motor, and the compressor is used to compress the refrigerant to make the cooler Cooling, recooling the interior of the cooling chamber, characterized in that it includes an inverter circuit that supplies three-phase drive current to the stator coil of the motor, a PWM circuit that supplies PWM signals to the inverter circuit, and detects the three-phase The driving current detection unit of the driving current converts the detected three-phase driving current into a d-axis current corresponding to the magnetic flux and a g-axis current corresponding to the torque of the motor. unit, a speed detection unit that detects the speed of the motor, a main control unit that outputs a speed command signal according to the converted q-axis current, and sends the PWM signal to the PWM according to the detected current speed and the speed command signal The circuit outputs a control signal to make the motor speed change to the speed control unit corresponding to the speed command signal, the main control unit controls the speed command signal corresponding to the change rate of the q-axis current, and adjusts the refrigeration cycle The refrigerant flow rate flowing in to control the temperature inside the refrigerator of the cooling chamber.

A second aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the main control unit outputs the speed command signal when the rate of change of the q-axis current is positive to increase the rotation speed. .

A third aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the main control unit outputs the speed command signal when the rate of change of the q-axis current is negative so that the Motor speed drops.

A fourth aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the refrigerator has a cooling fan near the cooler, and the main control unit controls the The speed change of the cooling fan described above.

A fifth aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the refrigerator has a door detection unit for detecting the opening and closing of the cooling chamber door, and the main control unit is in the The door detection unit controls the temperature inside the refrigerator after detecting the state of the door being closed.

A sixth aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the refrigerator has a door detection unit that detects the opening and closing state of the door of the cooling chamber, and the main control unit is located in the refrigerator. The temperature in the refrigerator is controlled after a predetermined time elapses after the door detection unit detects that the door is closed.

A seventh aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the main control unit obtains instantaneous electric power from the q-axis current and displays it on a display unit.

An eighth aspect of the present application is the electric drive unit of the refrigerator according to the first aspect, wherein the rotational speed detection unit performs calculations based on the three-phase drive current detected by the drive current detection unit.

A ninth aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the rotational speed detection unit performs calculation based on a position signal from a position detection unit provided near the motor rotor.

A tenth aspect of the present application is the motor drive device for a refrigerator according to the first aspect, wherein the motor is a three-phase induction motor or a three-phase brushless DC motor.

The eleventh aspect of the present application is a cooling fan driving device for a refrigerator, including a refrigeration cycle with at least a compressor rotating by a three-phase motor, a condenser, and a cooler. The cooling fan that sends the cold air cooled by the cooler to the room is characterized in that it includes an inverter circuit that supplies a three-phase drive current to the stator coil of the fan motor that rotates the cooling fan, and supplies the inverter circuit with A PWM circuit that supplies a PWM signal, a drive current detection unit that detects the three-phase drive current, converts the detected three-phase drive current into a current component corresponding to magnetic flux, that is, a d-axis current, and communicates with the fan motor The dq transformation unit of the q-axis current corresponding to the current component, the speed detection unit that detects the speed of the fan motor, the main control unit that outputs a speed command signal according to the transformed q-axis current, and the detected current The rotational speed and the speed command signal output a control signal to the PWM circuit so that the motor speed becomes a speed control unit corresponding to the speed command signal, and the main control unit is proportional to the change rate of the q-axis current Correspondingly controlling the speed command signal, adjusting the flow of cold air sent by the cooling fan to control the temperature inside the refrigerator in the cooling chamber.

A twelfth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the main control unit outputs the speed command signal when the rate of change of the q-axis current is positive so that The speed increases.

A thirteenth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the main control unit outputs the speed command signal so that when the rate of change of the q-axis current is negative, The motor speed drops.

A fourteenth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the refrigerator has a door detection unit that detects the opening and closing of the cooling chamber door, and the main control unit is in the The door detection unit controls the temperature inside the refrigerator after detecting the door closed state.

A fifteenth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the main control unit judges that the cooler is on when the converted q-axis current reaches a predetermined value. Frost.

A sixteenth aspect of the present application is the cooling fan drive device for a refrigerator according to the eleventh aspect, wherein the main control unit is configured to perform the operation when the converted q-axis current rises above a predetermined value, or by the The cooling fan is determined to be in a locked (Locked) state when the rotational speed detected by the rotational speed detection means is equal to or lower than a predetermined rotational speed.

A seventeenth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein when the main control unit controls the temperature inside the refrigerator in the cooling chamber, when the cooling fan is stopping, , to force the cooling fan to rotate.

An eighteenth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the rotational speed detection unit performs calculations based on the three-phase drive current detected by the current detection unit.

A nineteenth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the rotational speed detection unit performs the operation based on a position signal from a position detection unit provided near the rotor of the cooling fan motor. operation.

A twentieth aspect of the present application is the cooling fan driving device for a refrigerator according to the eleventh aspect, wherein the fan motor is a three-phase induction motor or a three-phase brushless DC motor.

Invention effect

Next, the operating state of the refrigerator motor drive device according to the first aspect will be described.

The motor drives the compressor to rotate to send the refrigerant into the cooler and freeze the cooler. At this time, if the refrigerator door is opened to enter food, the temperature inside the refrigerator will rise. As the temperature inside the refrigerator rises, the temperature around the cooler also rises, and the evaporation of the refrigerant flowing in the cooler increases. Thus, the load on the compressor increases.

On the other hand, since the motor that rotates the compressor is controlled to rotate at a constant speed by the control unit of the refrigerator, the driving current increases as the load on the compressor increases.

The dq converting unit converts the detected drive current into a d-axis current which is a current component corresponding to 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 main control unit, the main control unit outputs a speed command signal corresponding to the rate of change of the q-axis current.

The speed control unit outputs a control signal to the PWM circuit to change the speed corresponding to the speed command signal according to the current speed of the motor detected by the speed detection unit and the speed command signal from the main control unit.

The PWM circuit supplies the PWM signal to the inverter circuit in response to the control signal, and controls the inverter circuit.

The inverter circuit outputs a three-phase drive current to the three-phase stator coils of the motor according to the PWM signal.

Thus, the main control unit controls the speed command signal corresponding to the rate of change of the q-axis current, and can control the rotation speed of the compressor to adjust the refrigerant flow rate flowing in the refrigeration cycle.

Using the above method, when the food is put into the refrigerator, the temperature of the room rises, and the load of the compressor also rises, and the q-axis current increases. Corresponding to the rate of change of the increased q-axis current, the refrigerant flow rate is increased by adjusting the rotation speed of the motor to lower the temperature in the refrigerator. Therefore, the indoor temperature of the cooling chamber can be controlled without using a temperature sensor.

In the refrigerator motor driving device according to the second aspect, the main control unit judges that food is put into the refrigerator when the rate of change of the q-axis current is positive, and outputs a speed command signal to increase the rotation speed.

In the refrigerator motor driving device according to the third aspect, the main control unit judges that the food in the refrigerator has been sufficiently cooled when the rate of change of the q-axis current is negative, and outputs a speed command signal to lower the rotation speed.

In the refrigerator motor drive device according to the fourth aspect, the main control unit controls the rotation speed of the cooling fan according to the food put in the refrigerator by changing the rotation speed of the cooling fan according to the q-axis current.

In the refrigerator motor drive device according to claim 5, the main control unit controls the temperature inside the refrigerator when the door is detected to be closed. This is most likely due to the temperature rise in the refrigerator when food is placed in the refrigerator when the door is opened and then closed.

In the refrigerator motor drive device according to claim 6, the main control unit does not control the temperature inside the refrigerator until a predetermined time elapses after detecting the door-closed state. Even when the door is opened and then closed in this point, it is not limited to putting in food. Therefore, if food is put in, the temperature in the refrigerator rises after a predetermined time, and if no food is put in, the temperature in the refrigerator remains, so the temperature in the refrigerator is controlled after a predetermined time has elapsed for the above judgment.

In the refrigerator motor driving device according to claim 7, the main control unit obtains the instantaneous electric power from the q-axis current and displays it on the display unit, so that the current instantaneous electric power can be displayed to the user.

In the refrigerator motor driving device according to the eighth aspect, the rotational speed is calculated from the driving current detected by the driving current detecting means, thereby realizing a sensorless motor driving device and saving cost.

In the refrigerator motor driving device according to claim 9, since the rotation speed is detected based on the position signal from the position detection means provided near the rotor of the motor, the correct rotation speed can be detected.

In the refrigerator motor driving device according to the tenth aspect, a three-phase induction motor or a three-phase brushless DC motor is used as the motor, so that the compressor can be driven accurately and reliably.

Hereinafter, the operating state of the refrigerator cooling fan driving device according to the eleventh aspect will be described.

The fan motor is used to drive the cooling fan to rotate to send cold air to the cooling chamber. At this time, the refrigerator door is opened and food is put in. The air flow of the cold air changes with the amount of food put in, and the motor load increases or decreases. Since the fan motor is controlled by the main control unit of the refrigerator to rotate at a constant speed, the driving current changes according to the load of the motor.

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

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

The speed control unit outputs a control signal to the PWM circuit to change the speed corresponding to the speed command signal according to the current speed of the fan motor detected by the speed detection unit and the speed command signal from the main control unit.

The PWM circuit supplies the PWM signal to the inverter circuit in response to the control signal to control the inverter circuit.

The inverter circuit outputs a three-phase drive current to the three-phase stator coil of the fan motor according to the PWM signal.

With the above method, when the food is placed in the cooling chamber, the flow of cold air becomes poor, and the load on the cooling fan also increases accordingly, so the q-axis current increases. Corresponding to the rate of change of the increased q-axis current, the refrigerant flow rate is increased by increasing the rotation speed of the cooling fan, thereby reducing the temperature in the refrigerator. Therefore, the indoor temperature of the cooling chamber can be controlled without using a temperature sensor.

In the refrigerator fan motor driving device according to the twelfth aspect, the main control unit judges that it is difficult to put the food into the refrigerator at the timing of the rate of change of the q-axis current, so it outputs a speed command signal to increase the rotation speed.

In the refrigerator fan motor driving device according to the thirteenth aspect, when the rate of change of the q-axis current is negative, the main control unit can easily judge that the amount of food stored in the refrigerator decreases and the flow of cold air becomes easier, and outputs a speed command signal to reduce the rotation speed.

In the refrigerator fan motor drive device according to claim 14, the main control unit controls the temperature inside the refrigerator when the door-closed state is detected. This is because the temperature inside the refrigerator is likely to rise by putting food in the refrigerator when the door is opened and then closed.

In the refrigerator cooling fan driving device according to the fifteenth aspect, the main control unit detects the accumulation of frost on the cooler when the converted q-axis current reaches a predetermined value, for example, focusing on the flow of cold air, and when the cooling fan is positioned at the side of the cooler On the downstream side, when frost builds up on the cooler, the flow of cold air deteriorates, the air pressure around the cooling fan decreases, the load on the fan motor decreases, and the q-axis current also decreases. Therefore, when the q-axis current is lower than a predetermined value, it is judged that there is frost accumulation. In addition, focusing on the flow of cold air, if the cooling fan is located upstream of the cooler, the flow of cold air will deteriorate when frost builds up on the cooler, the air pressure around the cooling fan will increase, the load on the fan motor will increase, and the q-axis current will increase. also rose. Accordingly, when the value of the q-axis current is greater than a predetermined value, it is determined that frost has accumulated.

In the refrigerator cooling fan driving device according to the sixteenth aspect, the main control unit determines that the cooling fan is active when the converted q-axis current rises above a predetermined value, or when the rotational speed detected by the rotational speed detection unit is lower than a predetermined rotational speed. brake. Accordingly, it is possible to reliably detect the state of the cooling fan brake.

In the refrigerator cooling fan driving device according to claim 17, the main control unit forcibly rotates the cooling fan while the cooling fan is stopping when controlling the indoor temperature of the cooling chamber. This is because when the temperature control in the refrigerator as described in the first aspect is performed, the cooling fan cannot be controlled unless the cooling fan is rotated, so the cooling fan is forcibly rotated.

In the refrigerator cooling fan driving device according to the eighteenth aspect, by calculating the rotational speed based on the driving current detected by the driving current detection means, a sensorless cooling fan driving device can be realized, and cost can be saved.

In the refrigerator cooling fan driving device according to the nineteenth aspect, the rotation speed is detected based on the position signal from the position detection means provided near the rotor of the fan motor, so that the correct rotation speed can be detected.

In the refrigerator cooling fan driving device according to claim 20, a three-phase induction motor or a three-phase brushless DC fan motor is used as the fan motor, so that the cooling fan can be driven correctly and reliably.

Description of drawings

Fig. 1 is a block diagram of a refrigerator according to an embodiment of the present invention.

Figure 2 is a vector diagram of αβ changes starting from three phases.

Fig. 3 is a vector diagram of dq changes starting from αβ.

Fig. 4 is a time chart showing the relationship among cooler temperature, refrigerator interior temperature, q-axis current, and time.

Fig. 5 is a longitudinal sectional view of the refrigerator of the present embodiment.

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

Fig. 7 is a block diagram of a refrigerator according to an embodiment of the present invention.

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 braking detection method of the cooling fan.

Symbol Description

1A compressor drive

2 main control unit

3A compressor motor

4A fan driver

5A fan motor

10 refrigerator

14 cold room

16 vegetable room

18 1st Freezer

20 2nd Freezer

22 cooler

24 cooling fans

28 compressors

30 freezer cycles

42 inverter circuit

48A PWM forming unit

52dq transform unit

58A speed PI control unit

66A speed PI control unit

64 three-phase conversion unit

68A PWM forming unit

1B Fan drive unit

3B fan motor

4B Compressor drive

5B compressor motor

48B, 68B PWM formation unit

58B, 66B speed PI control unit

Detailed ways

Hereinafter, a refrigerator 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6 .

(1) The structure of the refrigerator 10,

The configuration of refrigerator 10 will be described with reference to FIG. 5 .

As shown in FIG. 5 , a refrigerator compartment 14 , a vegetable compartment 16 , a first freezer compartment 18 , and a second freezer compartment 20 are provided sequentially from top to bottom in the cabinet 12 of the refrigerator 10 , and doors 14 a to 20 a are provided on each compartment.

The main control unit 2 of the refrigerator 10 constituted by a microcomputer is provided on the back of the refrigerator compartment 14 .

A cooler 22 is installed on the back of the first freezer compartment 18 , and a cooling fan 24 is installed above the cooler 22 .

A machine room 26 is provided on the back of the second freezer room 20, and a compressor 28 is installed in the machine room 26.

(2) Configuration of the refrigeration cycle 30 .

The configuration of the refrigeration cycle 30 will be described with reference to FIG. 8 .

The refrigerant sent by the compressor 28 passes through the condenser 32 to the capillary tube 34 .

The refrigerant flowing out of the capillary tube 34 returns to the compressor 28 for circulation after being evaporated in the cooler 22 .

The air cooled by the cooler 22 is blown by a cooling fan, and blown to each small chamber 14-20 of the refrigerator 10 .

The sent cold air returns to the cooler 22 for circulation again after circulating in the refrigerator.

(3) Structure of the electrical system of the refrigerator 10

The configuration of the electrical system of the refrigerator 10 will be described with reference to the block diagram of FIG. 1 .

As shown in FIG. 1 , it is composed of a compressor motor 3A that drives the compressor 28 , a compressor drive device 1A that drives the compressor motor 3A, and a main control unit 2 that controls the compressor drive device 1A. Further, a fan drive unit 4A for driving a fan motor 5A of a cooling fan 24 is connected to the compressor drive unit 1A. Furthermore, the main control unit 2 is connected to the door switches 14b, 16b, 18b, and 20b provided on the doors 14a-20a of the respective chambers 14-20, respectively.

Hereinafter, the configuration of the compressor driving device 1A will be described first.

The compressor driving device 1A is composed of the following parts: an inverter circuit 42, a rectification circuit 44, an AC power supply 46, a PWM forming unit 48A, an AD conversion unit 50, a dq conversion unit 52, a speed detection unit 54, and a speed command output unit 56 . Speed PI control unit 58A, q-axis current PI control unit 60 , d-axis current PI control unit 62 and three-phase conversion unit 64 .

The compressor motor 3A that rotates the compressor 28 is a three-phase brushless DC motor. A three-phase drive current of the inverter circuit 42 flows through the three-phase (u, v, w) stator windings 40u, 40v, 40w of the compressor motor 3A.

The inverter circuit 42 is composed of six transistors Tr1 to Tr6 which are power switching semiconductors. In addition, although not shown in the drawing, diodes are connected in parallel with the switching transistors Tr1 to Tr6 in the reverse direction. Also connected in series with the switching transistors Tr1 and Tr4 is a detection resistor R1 for detecting a driving current, in series with the switching transistors Tr2 and Tr5 is connected a detection resistor R2, and in series with the switching transistors Tr3 and Tr6 is connected in series with a detection resistor R3.

The rectifier circuit 44 is supplied with an AC voltage from an AC power source 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 three-phase voltages Vu, Vv, Vw which will be described later. The switching transistors Tr1 to Tr6 are turned on/off at predetermined timings.

The AD conversion unit 50 detects the voltage values on the detection resistors R1, R2, R3, converts the voltage values of each phase from analog to digital, and outputs three-phase drive currents Iu, Iv, Iw.

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

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

$\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; I\&alpha;</span>}\\ \mathrm{<span\; class="notranslate">\; I\&beta;</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}}\left[\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}& <span\; class="notranslate">\; -</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\end{array}\right]\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; Iu</span>}\\ \mathrm{<span\; class="notranslate">\; IV</span>}\\ \mathrm{<span\; class="notranslate">\; Iw</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Then, the two-phase currents Iα and Iβ converted in this way are converted into q-axis current Iq and d-axis current Id using the formula (2). The relationship between the two-phase drive currents, the q-axis current Iq, and the d-axis current Id has a vector diagram as shown in FIG. 3 .

$\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; ID</span>}\\ \mathrm{<span\; class="notranslate">\; Iq</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right]\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; I\&alpha;</span>}\\ \mathrm{<span\; class="notranslate">\; I\&beta;</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

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

The main control unit 2 outputs a speed command signal S according to the q-axis current Iq sent by the dq conversion unit 52 . Such a control method will be described later.

The speed command output unit 56 outputs a reference rotational speed ωref based on the speed command signal S of the main control unit 2 and the rotational speed ω of the speed detection unit 54 . The reference rotation speed ωref 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 q-axis current Iqref and the reference d-axis current Idref, and the current q-axis current Iq and the current d-axis current Id are output together to the q-axis current PI control unit 60 and the d-axis current PI control unit 62, respectively. .

The q-axis current PI control unit 60 performs current/voltage conversion while performing PI control, and outputs a q-axis voltage Vq.

The d-axis current PI control unit 62 performs current/voltage conversion while performing PI control, and outputs a d-axis voltage Vd.

In the three-phase conversion unit 64, the d-axis voltage Vd and the q-axis voltage Vq are first converted into two-phase voltages according to the formula (3).

$\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; V\&alpha;</span>}\\ \mathrm{<span\; class="notranslate">\; V\&beta;</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right]\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; Vd</span>}\\ \mathrm{<span\; class="notranslate">\; wxya</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

The converted two-phase voltages Vα, Vβ are converted into three-phase voltages Vu, Vv, Vw according to equation (4).

$\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; Vu</span>}\\ \mathrm{<span\; class="notranslate">\; Vv</span>}\\ \mathrm{<span\; class="notranslate">\; Vw</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}}\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}& \sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}& <span\; class="notranslate">\; -</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\end{array}\right]\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; V\&alpha;</span>}\\ \mathrm{<span\; class="notranslate">\; V\&beta;</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

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

With the above-mentioned compressor drive device 1A, the rotation speed is detected based on the d-axis current Id and the q-axis current Iq, and feedback control is performed based on the rotation speed ω and the speed command signal S of the main control unit, from the PWM forming unit 48A to the inverter circuit 42. The output of the PWM signal causes the compressor motor 3 to rotate at the rotational speed ωref that matches the speed command signal S. The inverter circuit 42 accordingly outputs a three-phase drive current to the three-phase stator winding 40 of the compressor motor 3A.

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

The reference rotational speed ωref from the speed command output unit 56 is input to the fan driving device 4A, and the rotation of the cooling fan 24 is controlled accordingly. In addition, the fan motor 5A is a three-phase brushless DC motor.

The fan driving device 4A, like the compressor driving device 1A, controls the rotating speed by sending the PWM signal formed by the speed PI control unit 66A and the PWM forming unit 68A to the driving circuit 70 to output a three-phase driving current to the fan motor 5A according to the reference rotating speed ωref .

(4) The first control method of refrigerator temperature

Now, the first control method for adjusting the temperature inside the refrigerator in the refrigerator 10 constructed as above will be described.

In the refrigerator 10 of the above-mentioned structure, when food is stored in at least one of the refrigerator compartment 14, the vegetable compartment 16, the first freezer compartment 18, and the second freezer compartment 20, the temperature in the refrigerator will rise due to the heat capacity held by the food. . Then, the temperature of the air returning through the refrigerator inside the cooler 22 rises, the amount of refrigerant evaporated in the cooler 22 increases, and the load on the refrigeration cycle 30, that is, the compressor 28 increases.

In this case, the rotational speed of the compressor motor 3A is controlled to be constant based on the speed command signal S from the main control unit 2 of the refrigerator 10, so that the torque applied to the compressor motor 3A increases.

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

According to the method described above, when the temperature inside the refrigerator continues to rise due to the heat capacity of the food, the load on the refrigeration cycle 30 increases, so the q-axis current Iq also increases.

The amount of change of the q-axis current Iq is proportional to the heat capacity of the food in the refrigerator, so the main control unit 2 calculates the slope of the q-axis current Iq output by the dq conversion unit, and according to the slope (increment per unit time) The main control unit 2 controls the speed command signal S to control the speed of the compressor motor 3A and the cooling fan 24 to increase.

Thus, when food is put in, the rotation speed of compressor motor 3A and cooling fan 24 increases correspondingly to increase the capacity of refrigeration cycle 30, preventing the tendency of the temperature of the refrigerator to rise due to the food put in, and maintaining the temperature in the refrigerator. at a certain temperature.

On the other hand, after a period of time after the food is put in, the temperature in the refrigerator drops after the food is cooled, and when the load on the compressor 28 in the refrigerating cycle 30 is reduced, the q-axis current Iq also drops, so the main The control unit 2 calculates the decrease rate of the q-axis current Iq per unit time, and outputs a speed command signal S to decrease the rotation speeds of the compressor motor 3A and the cooling fan 24 accordingly. Through this, when the temperature of the food to be put in is low, the capacity of the compressor 28 is also reduced, and the temperature in the refrigerator will not be lower than the prescribed temperature range.

(5) The second control method of the temperature in the refrigerator

A second method of controlling the temperature inside the refrigerator, which replaces the first method of control described above, will now be described.

In the first control method, the rate of change of the q-axis current Iq is obtained after the temperature of the food refrigerator starts to rise, and in the second control method, as shown in Fig. 4, each chamber The timing when the doors 14a-20a of 14-20 are opened and then closed is controlled.

Specifically, must open at least one door (such as the refrigerator compartment 14a) in each small chamber 14～20 when putting food into, then close again. Therefore, the main control unit 2 also starts to detect the rate of change of the q-axis current Iq from the time when the closed state of the door 14a is detected by the door switch 14b.

And, as shown in FIG. 4, when the temperature inside the box rises due to the heat capacity held by the stored food, and the q-axis current Iq also increases, the main control unit 2 obtains the slope of the q-axis current Iq and compares it with the slope of the q-axis current Iq per unit time. The increase in the rate of change increases the rotational speeds of the compressor motor 3A and the cooling fan 24 in accordance with the output speed command signal S.

In this way, it is possible to accurately detect the time when the food is put into the refrigerator, and it is convenient to control the temperature inside the refrigerator. For example, even if the door is opened and closed but no food is put in, the q-axis current Iq does not increase because the temperature inside the refrigerator rises only slightly, so it is not necessary to control the temperature inside the refrigerator. In addition, when putting hot food and other food with large heat capacity, or food at normal temperature, the above-mentioned control method must be implemented due to the temperature rise in the box. Moreover, the timing of whether or not to perform the control can be accurately and reliably detected from the signals of the door switches 14b to 20b.

(6) The third control method of the temperature in the refrigerator

Hereinafter, a third method of controlling the temperature inside the refrigerator 10 will be described.

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

That is, if food with a heat capacity is put in, it is not clear whether the temperature inside the box rises due to opening the door, or whether the temperature inside the box rises due to the heat capacity of the food. Therefore, the main control unit 2 measures the rate of change of the q-axis current Iq after a predetermined time t0 has elapsed after the door is closed.

For example, when only opening and closing the door or putting in food with a small heat capacity, the q-axis current Iq after the predetermined time t0 has elapsed after the door is closed once rises and then decreases at a large rate. That is, the q-axis current Iq also increases due to the opening and closing of the door shortly after the door is closed, but if only the door is opened or closed or food with a small heat capacity is put in, the decrease rate of the q-axis current Iq after the increase becomes large. When the decrease rate is large, the main control unit 2 judges that there is almost no load and outputs the speed command signal S so that the rotation speed is maintained, or the rotation speed increases slightly even if it increases.

On the other hand, it is conceivable that the rate of decrease of the q-axis current Iq after the lapse of the predetermined time t0 is small when food with a large heat capacity is inserted, or on the contrary does not decrease but increases. Therefore, when the q-axis current Iq decreases or increases after the predetermined time t0, it is determined that food with a large load has been put in, and the speed command signal S is output to increase the rotation speed of the compressor motor 3A and the cooling fan 24.

(7) The fourth control method of the temperature in the refrigerator

In the third control method, the speed command signal S is output according to the rate of change of the q-axis current Iq after a predetermined time t0 has elapsed since the door is closed, but in the fourth control method, the speed command signal S is output according to the After recording the maximum value of the q-axis current Iq, it is judged whether the reduction rate is large or small.

For example, measure the rate of change of the q-axis current Iq after the maximum value is measured. If the rate of decrease after the maximum value is large, it means that the heat load is small or the door is only opened and closed. If the rate of decrease is small In this case, it is judged that food with a large thermal load is put in, and the speed of the corresponding compressor motor 3A and cooling fan 24 can be controlled according to the speed command signal S.

It is also conceivable that when food with a large thermal load is placed and the maximum value of the q-axis current Iq is not continuously measured, the value of the q-axis current Iq increases. In this case, the maximum value is not measured even after the specified time t1 value, it is judged that the q-axis current Iq continues to increase and output the speed command signal S to rotate the compressor motor 3A and the cooling fan 24 according to the maximum rotation speed.

(8) The fifth control method of the temperature in the refrigerator

The fifth control method calculates the door opening time according to the door opening and closing signals detected by the door switches 14b-20b. At the same time, the q-axis current Iq is used to detect the increase of the torque as the load of the refrigerating cycle 30 increases after the door is closed. Moreover, the rotation speeds of the compressor 28 and the cooling fan 24 are controlled according to the opening and closing time of the door and the change of the q-axis current Iq so that the temperature in the cabinet can be maintained.

Specifically, it is controlled so that the more the door is opened, the more the increase rate of the q-axis current Iq is, the more the speed is increased.

(9) Modification example

The above-mentioned control methods use the q-axis current Iq to only control the temperature in the refrigerator. In addition, the main control unit 2 is connected to a liquid crystal display unit capable of digital display, and is calculated according to the torque component of the compressor motor 3, that is, the q-axis current Iq The instantaneous electric power consumed by the compressor motor 3A is displayed on the liquid crystal display unit.

For example, by installing the liquid crystal display unit in front of the door 14a of the refrigerator compartment 14, the user can confirm the current power consumption of the refrigerator.

(change example)

The above-described embodiment is one embodiment of the present invention, and changes can be made as long as they do not deviate from the gist of the present invention.

(1) Modification 1

In the refrigerator 10 of the above-mentioned embodiment, there is only one cooler, but it is also possible to separately install the cooler for the refrigerator compartment and the cooler for the freezer compartment, and implement the five control methods described in the above-mentioned embodiment on the respective coolers.

(2) Modification 2

Both the compressor motor 3A and the fan motor 5A are three-phase brushless DC motors, but a three-phase induction motor may be used instead.

Next, other embodiments of the present invention will be described with reference to FIGS. 1 to 3 and FIGS. 5 to 8 .

(1) Structure of refrigerator 10

The structure of the refrigerator 10 has been described with reference to FIG. 5 .

(2) Configuration of the refrigeration cycle 30

The configuration of the refrigeration cycle 30 has been described with reference to FIG. 6 .

(3) The electrical system configuration of the refrigerator 10

Referring now to the block diagram of Fig. 7, the electrical system configuration of the refrigerator 10 will be described. Now, the parts marked with the same symbols as in Fig. 1 have the same configuration as in Fig. 1, and their descriptions are omitted. As shown in FIG. 7 , it is composed of a fan motor 3B that drives the cooling fan 24 , a cooling fan drive unit 1B that drives the fan motor 3B, and a main control unit 2 that controls the cooling fan drive unit 1B. In addition, the cooling fan drive unit 1B is connected to a compressor drive unit 4B for a compressor motor 5B that drives the compressor 28 . Furthermore, the main control unit 2 is connected to the door switches 14b, 16b, 18b, and 20b respectively provided on the doors 14a-20a of the respective compartments 14-20.

First, the configuration of the cooling fan drive unit 1B will be described.

The cooling fan driving device 1B is composed of an inverter circuit 42, a rectification circuit 44, an AC power supply 46, a PWM forming unit 48B, an AD conversion unit 50, a dq conversion unit 52, a speed detection unit 54, a speed command output unit 56, and a speed PI control unit. 58B, a q-axis current PI control unit 60 , a d-axis current PI control unit 62 , and a three-phase conversion unit 64 constitute.

The fan motor 3B that rotates the cooling fan 24 is a three-phase brushless DC motor. A three-phase drive current of the inverter circuit 42 flows through the three-phase (u-phase, v-phase, w-phase) stator windings 40u, 40v, 40w of the fan motor 3B.

The PWM forming unit 48B supplies PWM signals to the gate terminals of the six switching transistors Tr1 to Tr6 . The PWM forming unit 48B performs pulse width modulation based on three-phase voltages Vu, Vv, and Vw to be described later, and turns on/off each of the switching transistors Tr1 to Tr6 at predetermined timings.

The AD conversion unit 50 detects voltage values on the detected resistors R1, R2, and R3, converts the voltage values of each phase from analog to digital, and outputs three-phase drive currents Iu, Iv, and Iw.

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

The speed detection unit 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. The rotation angle θ, which is the rotor position of the fan motor 3B, is obtained from the q-axis current and the d-axis current, and the rotational speed is obtained by differentiating the rotation angle θ.

The main control unit 2 outputs a speed command signal S according to the q-axis current Iq sent by the dq conversion unit 52 . This control method will be described later.

The speed command output unit 56 outputs a reference rotational speed ωref based on the speed command signal S of the main control unit 2 and the rotational speed ω of the speed detection unit 54 . The reference rotation speed ωref is input to the speed PI control unit 58B together with 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 current q-axis current Iq and the current d-axis current Id are output together to the q-axis current PI control unit 60 and the d-axis current PI control unit 62, respectively. .

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

Using the above cooling fan driving device 1B to detect the rotational speed based on the d-axis current Id and the q-axis current Iq, and to perform feedback control based on the rotational speed ω and the speed command signal S from the main control unit 2, the PWM forming unit 48B is sent to the inverter circuit 42 outputs a PWM signal so that the fan motor 3 rotates at a rotation speed ωref that matches the speed command signal S. The inverter circuit 42 accordingly outputs a three-phase drive current to the three-phase stator winding 40 of the fan motor 3B.

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

The reference rotation speed ωref from the speed command output unit 56 is input to the compressor driving device 4B, and the rotation of the compressor 28 is controlled accordingly. In addition, the compressor motor 5B is a three-phase brushless DC motor.

The compressor driving device 4B, like the cooling fan driving device 1B, sends the PWM signal formed by the speed PI control unit 66B and the PWM forming unit 68B to the inverter circuit 70 according to the reference rotational speed ωref, and outputs the three-phase drive signal to the compressor motor 5B. The current controls the speed.

(4) The sixth control method of the temperature in the refrigerator

A sixth control method for adjusting the temperature inside the refrigerator in the refrigerator 10 having the above-mentioned configuration will be described.

In the refrigerator 10 of the above-mentioned structure, if food is stored in at least one of the refrigerator compartment 14, the vegetable compartment 16, the first freezer compartment 18, and the second freezer compartment 20, the flow of cold air will be deteriorated due to the food, and the The load of the cooling fan 24 sending cold air increases.

At this time, the rotational speed of 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 rotational speed of the fan motor 3B is kept constant, so the torque applied to the fan motor 3B increases.

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

As a result of the above method, the flow of cold air deteriorates as soon as the food is put in, and the load on the cooling fan 24 increases, so the q-axis current Iq also increases.

The amount of change of this q-axis current Iq is proportional to the amount of food put in the refrigerator, so the main control unit 2 calculates the slope of the q-axis current Iq output by the dq conversion unit, and the slope (increase per unit time) The main control unit 2 controls the speed command signal S to increase the speed of the fan motor 3B and the compressor motor 5B corresponding to the value of the speed.

Thus, as soon as the food is put in, the cooling capacity is increased correspondingly by the rotation speed of the fan motor 3B and the compressor motor 5B, which prevents the temperature inside the refrigerator from rising due to the food being put in, so that the temperature in the refrigerator is kept constant.

In addition, as soon as the food is taken out, only the part of the food taken out improves the flow of cold air and reduces the load on the cooling fan 24, and the q-axis current Iq also decreases. The main control unit 2 calculates the rate of decrease of the q-axis current Iq per unit time, and outputs a speed command signal S to decrease the rotational speeds of the fan motor 3B and the compressor motor 5B accordingly. In this way, when the food is taken out, the ability of the cooling fan 24 is also lowered, so that the temperature in the refrigerator does not fall below the predetermined temperature range.

(5) The seventh control method of the temperature in the refrigerator

Now, the seventh control method of the temperature in the refrigerator will be described instead of the sixth control method above.

The sixth control method is to obtain the rate of change of the q-axis current Iq after the temperature of the food is put into the box to rise, and the seventh control method is to open the doors of each chamber 14-20 as shown in Figure 4 14a to 20a are controlled according to the time when they are closed later.

Specifically, the door (for example, the refrigerator compartment 14a) of at least one of the compartments 14 to 20 is opened when food is put in, and then closed. Therefore, the main control unit 2 starts to detect the rate of change of the q-axis current Iq from the time when the closed state of the door 14a is detected by the door switch 14b.

By using this detection, it is possible to accurately detect the time when food is put in, and it is easy to control the temperature in the refrigerator. For example, even when the door is opened but no food is put in, since the flow of cold air does not change, the q-axis current Iq does not increase, and there is no need to control the temperature in the refrigerator. In addition, when a large amount of food is put in, the above-mentioned control method must be adopted because the flow of cold air is deteriorated. Furthermore, the timing when the control is performed and the timing when the control is not performed can be accurately and reliably detected using the signals of the door switches 14b to 20b.

(6) Explanation on defrosting control method

The main control unit 2 detects the accumulation of frost on the cooler 22 when the converted q-axis current reaches a predetermined value (hereinafter referred to as the frost accumulation reference current value).

As mentioned above, if focusing on the flow of cold air, since the cooling fan 24 is on the downstream side of the cooler 22, when frost accumulation occurs on the cooler 22, the flow of the cold air will deteriorate, the air pressure around the cooling fan 24 will drop, and the fan motor 3B will The rotation load becomes easy to reduce, and the q-axis current also decreases. Therefore, when the value of the q-axis current is lower than the frost accumulation reference current value, it is judged that there is frost accumulation, and the defrosting control is started.

In addition, in the refrigerator 10 of this embodiment, the cooling fan 24 is located in the downstream side of the cooler 22, but focusing on the flow of cold air, the cooling fan 24 may be located in the upstream side of the cooler.

In this case, when frost accumulates on the cooler, the flow of cold air becomes poor, the air pressure around the cooling fan 24 increases, the load on the fan motor 3B increases, and the q-axis current also increases. Therefore, as shown in FIG. 8 , when the value of the q-axis current is greater than the frost reference current value at a predetermined rotational speed, it is judged that there is frost accumulation, and defrosting control is performed.

(7) Braking detection method of fan motor 3B

The braking detection method of the fan motor 3B will be described below.

The main control unit 2 determines that the cooling fan 24 is braked when the converted q-axis current rises to a predetermined value, or when the rotational speed detected by the speed detection unit 54 becomes below a predetermined rotational speed (for example, the rotational speed is zero). Thereby, the brake state of the cooling fan 24 can be reliably detected.

(8) Others

If the cooling fan 24 is stopped during the various controls described above, the q-axis current cannot be detected, so the cooling fan 24 is forcibly rotated.

(change example)

The above-mentioned embodiment is one other embodiment of the present invention, and it can be changed as long as it does not deviate from the gist of the present invention.

(1) Modification 1

The cooler in the refrigerator 10 in the above-mentioned embodiment is one, and the cooler and the cooling fan for the refrigerating room, the cooler and the cooling fan for the freezing room can also be separately installed, and the above-mentioned embodiment is implemented on the respective cooler and cooling fan. The control method described.

(2) Modification 2

Both the fan motor 3B and the compressor motor 5B are three-phase brushless DC motors, which can also be replaced by three-phase induction motors.

Industrial Applicability

The present invention is applicable to the temperature control in refrigerators with coolers, such as household refrigerators and various commercial refrigerators.

Claims (20)

1. the motor drive of a refrigerator possesses and has the freeze cycle that drives rotation compressor, condenser, cooler with threephase motor at least,

Utilize described compressor compresses cold-producing medium to make described cooler cooling, cool off cooling chamber inside again, it is characterized in that,

Have

To the stator coil of described motor supply with the three-phase drive electric current inverter circuit,

To described inverter circuit provide pwm signal pwm circuit,

Detect described three-phase drive electric current the drive current detecting unit,

According to described detected three-phase drive electric current, be transformed into the current component corresponding and be with magnetic flux the d shaft current and with the corresponding current component of the torque of described motor be the q shaft current the dq converter unit,

Detect described motor speed rotation speed detection unit,

According to the main control unit of the q shaft current output speed command signal after the described conversion and

According to described detected current rotating speed and described speed command signal, to described pwm circuit output control signal, make motor speed become the speed control unit of the rotating speed corresponding with described speed command signal,

The rate of change of described main control unit and described q shaft current is controlled described speed command signal accordingly, adjusts the refrigerant flow that flows in the described freeze cycle, controls the indoor temperature of described cooling chamber.

2. the motor drive of refrigerator as claimed in claim 1 is characterized in that, described main control unit is that described speed command signal is exported in timing at the rate of change of described q shaft current, makes rotating speed improve.

3. the motor drive of refrigerator as claimed in claim 1 is characterized in that, described main control unit is exported described speed command signal at the rate of change of described q shaft current when negative, makes described motor speed descend.

4. the motor drive of refrigerator as claimed in claim 1 is characterized in that, described refrigerator has cooling fan near described cooler, and described main control unit changes described speed of cooling fan according to described q shaft current.

5. the motor drive of refrigerator as claimed in claim 1, it is characterized in that, described refrigerator has the door detecting unit of the switching usefulness that detects described cooling chamber door, described main control unit described door detecting unit detect go out be in closed condition after to described refrigerator in temperature control.

6. the motor drive of refrigerator as claimed in claim 1, it is characterized in that, described refrigerator has the door detecting unit of the open and-shut mode of the door that detects described cooling chamber, described main control unit described door detecting unit detect described door be in closed condition after through the stipulated time after just to described refrigerator in temperature control.

7. the motor drive of refrigerator as claimed in claim 1 is characterized in that, described main control unit is obtained instantaneous electric power according to described q shaft current and shown on display unit.

8. the electric drive unit of refrigerator as claimed in claim 1 is characterized in that, described rotation speed detection unit is carried out computing according to the detected three-phase drive electric current of described drive current detecting unit.

9. the motor drive of refrigerator as claimed in claim 1 is characterized in that, described rotation speed detection unit is according to carrying out computing from the position signalling that is located near the position detection unit the described motor rotor.

10. the motor drive of refrigerator as claimed in claim 1 is characterized in that, described motor is three phase induction motor or three-phase brushless DC motor.

11. the cooling fan drive device of a refrigerator possesses and has the freeze cycle that is driven rotation compressor, condenser, cooler by threephase motor at least,

Have and be arranged near the described cooler, carry cooling fan, it is characterized in that through the cold air of described cooler cooling to described cooling chamber,

Have

To the fan motor stator coil that makes the rotation of described cooling fan supply with the three-phase drive electric current inverter circuit,

To described inverter circuit provide pwm signal pwm circuit,

Detect described three-phase drive electric current the drive current detecting unit,

According to described detected three-phase drive electric current, be transformed into the current component corresponding and be with magnetic flux the d shaft current and with the corresponding current component of the torque of described fan motor be the q shaft current the dq converter unit,

Detect described fan motor rotating speed rotation speed detection unit,

According to the q shaft current after the described conversion, the main control unit of output speed command signal and

According to described detected current rotating speed and described speed command signal, to described pwm circuit output control signal, make motor speed become the speed control unit of the rotating speed corresponding with described speed command signal,

The rate of change of described main control unit and described q shaft current is controlled described speed command signal accordingly, adjusts the cold air flow that described cooling fan is sent, and controls the indoor temperature of described cooling chamber.

12. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, described main control unit is timing at the rate of change of described q shaft current, exports described speed command signal rotating speed is improved.

13. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, when described main control unit is negative at the rate of change of described q shaft current, exports described speed command signal described motor speed is descended.

14. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, described refrigerator has the door detecting unit of the switching that detects described cooling chamber door,

Described main control unit described door detecting unit detect go out be in closed condition after temperature in the described refrigerator of control.

15. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, when the q shaft current of described main control unit after described conversion reaches setting, judges long-pending frost on the described cooler.

16. the cooling fan drive device of refrigerator as claimed in claim 11, it is characterized in that, the q shaft current of described main control unit after described conversion is raised to setting when above, or the detected rotating speed of described rotation speed detection unit is that the regulation rotating speed is judged described cooling fan braking when following.

17. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, described main control unit during temperature, when described thermantidote is stopping, being forced described cooling fan rotation in the refrigerator of the described cooling chamber of control.

18. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, described rotation speed detection unit is carried out computing according to the detected three-phase drive electric current of described drive current detecting unit.

19. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, described rotation speed detection unit is carried out computing according to the position signalling near the position detection unit the rotor that is located at described cooling fan motor.

20. the cooling fan drive device of refrigerator as claimed in claim 11 is characterized in that, described fan motor is three phase induction motor or three-phase brushless DC motor.

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