JPH05322410A - Refrigerator - Google Patents

Abstract

PURPOSE:To reduce the level of noise emission occurring at the start of a compressor by a method wherein the load torque of the compressor is calculated based on the result of detection of the operating conditions of a refrigerator and the revolution number of the compressor for producing the torque equal to the load torque thus obtained is calculated, thereby controlling the starting means of the compressor. CONSTITUTION:A refrigerator condition detecting means 1 is provided consisting of an interior refrigerator temp. detecting means 101, an exterior temp. detecting means 103, a means 105 for calculating the operating time of a compressor (hereinafter referred to as comp.) and a means 107 for detecting the comp. pressure and, based on the output from the refrigerator condition detecting means 1, a load torque calculating means 3 calculates the load torque required for starting the comp. 31 by retrieving a predetermined table. A means 5 for controlling comp. revolution number for its starting calculates the revolution number for producing the torque equivalent to the load torque obtained from the aforesaid calculation and controls a refrigerator control means 9 to start the comp. 31 at a speed of the revolution number thus obtained or in the neighborhood thereof. The revolution number of the comp. 31 is thereafter changed from the starting to the normal one by a comp. revolution number changing means 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator in which noise at startup of the compressor is reduced by controlling operation at startup of the compressor.

[0002]

2. Description of the Related Art In a refrigerator, when the temperature inside the refrigerator falls below a set temperature, a compressor is activated to control the temperature inside the refrigerator below the set temperature. Conventionally, such a compressor is started by rotating the compressor at a rotation speed of 60 Hz or 50 Hz, which is the same frequency as the frequency of the commercial power supply, or when the rotation speed can be controlled, the objective is to start from the start. Rotation speed, eg 30H
The compressor is started at the rotation speed of z or 90 Hz.

[0003]

As described above, conventionally, when the compressor is started, the compressor is started at the same speed as the commercial power source or at the target speed.
There is a problem that more torque is applied to the compressor and noise is generated from the compressor.

The present invention has been made in view of the above,
It is an object of the invention to provide a refrigerator that reduces noise when the compressor is started.

[0005]

In order to achieve the above object, the refrigerator of the present invention has an operating state detecting means for detecting the operating state of the refrigerator, and a compressor for the compressor based on the operating state detected by the operating state detecting means. Load torque calculating means for calculating the load torque, rotation speed calculating means for calculating the rotation speed of the compressor that generates torque equal to or less than the load torque of the compressor calculated by the load torque calculating means, and the rotation speed The gist is to have a starting means for starting the compressor at the rotation speed calculated by the number calculation means.

[0006]

In the refrigerator of the present invention, the load torque of the compressor is calculated based on the operating state of the refrigerator, the rotation speed of the compressor that generates torque equal to or less than the load torque is calculated, and the compressor is operated at the rotation speed. to start.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the functional arrangement of a refrigerator according to an embodiment of the present invention. As shown in the figure, the refrigerator of the present embodiment calculates the operating time of the inside temperature detecting means 101 for detecting the temperature inside the refrigerator, the outside air temperature detecting means 103 for detecting the outside air temperature outside the refrigerator, and the compressor. The refrigerator operating condition calculating means 105 and the compressor pressure detecting means 107 for detecting the pressure of the compressor such as the refrigerant suction pressure and the refrigerant discharge pressure of the compressor are included in the refrigerator state detecting means 1 and the refrigerator state detecting means 1 detects the refrigerator state. Information regarding each operating state is supplied to the load torque calculating means 3, where the load torque required to start the compressor is calculated from the operating state of the refrigerator. The calculation of the load torque by the load torque calculation means 3 is performed by the inside temperature detection means 101, the outside air temperature detection means 103, the compression operation time calculation means 105, and the compression pressure detection means 107 which constitute the refrigerator state detection means 1.
It is also possible to create a table in which the load torque is predicted in advance for each piece of information from 1) and search the table.

The load torque calculated by the load torque calculation means 3 is supplied to the compression start rotation speed control means 5, and the rotation speed for generating a torque equivalent to the load torque is calculated.
At this speed or at a speed around it, the compressor 31
The refrigerator control means 9 is controlled to activate the. The compressor 31 started via the refrigerator control means 9 by the rotation speed calculated by the comp start-up rotation speed control means 5 is gradually changed from the rotation speed at the time of startup to the normal rotation speed by the control of the compression rotation speed change control means 7. It can be raised to or at a stretch. The refrigerator control unit 9 determines whether the compressor 31 is on or off based on the inside temperature from the inside temperature detecting unit 101, the outside air temperature from the outside air temperature detecting unit 103, and executes the other operations of the refrigerator. To control.
Further, the compressor operation time information from the compressor operation time calculation means 105 is also supplied to the refrigerator control means 9.

FIG. 2 is a block diagram showing a more specific circuit configuration of the refrigerator shown in FIG. As shown in FIG.
The refrigerator according to the present embodiment is mainly composed of, for example, a CPU 11 including a microprocessor and the like, a ROM 13 for storing programs and fixed information, and a RAM 1 for temporarily storing information.
5, a computer including the interfaces 17 and 25 and a counter 33 is configured to control the entire operation, and the interface 17 constitutes the refrigerator state detecting means 1 and the inside temperature detecting means 101, the outside air temperature detecting means 103, and The temperature sensors 17 and 19 and the pressure sensors 21 and 23 corresponding to the compression pressure detecting means 107 are connected, and the interface 25 is provided with an inverter 27,
A compressor 31 is connected via a driver 29.

The temperature sensor 17 corresponds to the inside temperature detecting means 101 and detects the temperature inside the refrigerator. The temperature sensor 19 corresponds to the outside air temperature detecting means 103 and detects the temperature outside the refrigerator, that is, the outside air temperature. The pressure sensor 21 detects the refrigerant suction pressure of the compressor, and the pressure sensor 23 detects the refrigerant discharge pressure of the compressor.

The counter 33 corresponds to the compressor operation time calculating means 105 and is a counter for counting the off time of the compressor.

Next, the operation of the refrigerator constructed as described above will be described with reference to the flow chart shown in FIG.

In FIG. 3, when the refrigerator is performing normal processing (step 310), the temperature of the refrigerator is detected by the inside temperature detecting means 101, that is, the temperature sensor 17, and the detected inside temperature of the refrigerator is detected. Checks whether the compressor has risen to the on temperature, that is, the temperature at which the compressor should be turned on (step 32).
0). When the temperature in the refrigerator is the ON temperature of the compressor, the compressor 31 must be started. For this reason, the temperature sensors 17 and 19, the pressure sensors 21 and 23, and the compression operation time calculation means 10 are required.
5, that is, the refrigerator internal temperature, the outside air temperature, the compressor refrigerant suction pressure, the compressor refrigerant discharge pressure, and the compressor off time detected by the counter 33 are taken in, and the load torque is calculated from these information (step 330). The calculation of the load torque may be performed by searching using the table as described above.

When the load torque is calculated in step 330, the compressor corresponding to the load torque is first calculated from the calculated load torque in order to calculate the rotational speed of the compressor that generates a torque equivalent to the load torque. The voltage for operating 31 is retrieved from the data stored in advance in the ROM 13 (step 34).
0). Then, the retrieved voltage is applied to the interface 2
5, supplied to the compressor 31 via the inverter 27 and the driver 29, and starts the compressor (steps 350, 370).

The rotational speed of the compressor is roughly determined by the voltage applied to the compressor, as will be described later. Therefore, as described above, by supplying the voltage corresponding to the load torque to the compressor, the compressor can be rotated at the rotation speed corresponding to the load torque.

After starting the compressor 31 as described above, it is confirmed that the compressor has started (step 37).
0), and then by the comp rotation speed change control means 7,
That is, in FIG. 2, the compressor revolution speed is increased to a target revolution speed by the compressor revolution speed change control means 7 constituted by the CPU 11 and the ROM 13 as software (step 380), and then the normal operation is started (step 39).
0), then return to the first step 310.

FIG. 4 is a flow chart showing the operation of the refrigerator according to another embodiment of the present invention. The hardware configuration of the refrigerator in this embodiment is the same as that shown in FIGS. 1 and 2. In the embodiment shown in FIG. 4, the compressor is started while gradually increasing the rotation speed of the compressor from around zero.

In FIG. 4, when the refrigerator is performing normal processing (step 410), the temperature of the refrigerator is detected by the temperature sensor 17, and the detected temperature in the refrigerator rises to the ON temperature of the compressor. It is checked whether or not there is any (step 420). If the temperature in the refrigerator is the on temperature of the compressor, the compressor 3
1 is started from the point where the rotation speed is close to 0 (step 430).

When the compressor 31 is started, for example, 1
A fixed rate for each unit time of 00 ms (for example, 1 Hz)
While increasing the number of revolutions of the compressor, the number of revolutions is increased to the target number of revolutions (steps 440 to 460).

FIG. 5 is a diagram showing changes in the number of revolutions when the compressor is started with respect to time in the process shown in FIG. As can be seen in this figure and the processing described above, the rotation speed of the compressor gradually increases from a fairly low rotation speed.

Next, with reference to FIGS. 6 and 7, the operation of varying the rotation speed of the compressor by varying the voltage supplied to the compressor will be described.

FIG. 6 is a diagram showing a part of a circuit for controlling the rotation of the compressor motor. The rotation speed of the compressor motor is changed by changing the voltage applied to the compressor motor by the PAM transistor 51 shown in FIG. Can be changed.

FIG. 7 is a diagram showing characteristics of a DC motor used as a compressor motor. The rotation speed N of the DC motor has a relationship with the voltage V as shown in the following equation.

N = (V / K _E ) − (R τ / K _{E KT} ) where K _E is the induced voltage constant (V / rpm), _KT is the torque constant (kg · m / A), τ Is torque and τ =
K _T · I, R is the winding resistance of the motor coil, and I is the current.

As shown in FIG. 7, the voltage V is set to E1, E2,
When constant as E3 (E1>E2> E3), the rotation speed N
And the torque τ is as shown in FIG. Here, the rotational speed trying kept constant N _o, when the motor torque during startup compressor was tau _1, the temperature is lowered in the refrigerator, as the load of the compressor is stabilized, the torque of the motor Transitions to τ ₂ and τ ₃ . Therefore,
To keep the rotation speed constant, the voltage applied to the motor may be changed according to the torque τ at that time.
Therefore, if the torque required for starting the motor is known, the voltage for the target rotation speed can be known.

Table 1 shown below is a table showing an example of the compressor discharge pressure, the suction pressure, and the temperature of each part of the refrigerator at the number of revolutions of the compressor and the input power (W).
On the contrary, by knowing the pressure of the compressor and the temperature of each part of the refrigerator, the rotation speed of the compressor and the input power (W) can be known, and the torque required for the rotation of the compressor can be predicted. Therefore, if the torque is predicted from the information of each part of the refrigerator and the target rotation speed is determined, the voltage required for the rotation speed can be known.

[0028]

[Table 1] Although the above embodiment describes the control at the time of starting the compressor, the present invention can be applied by reversing the operation even when the compressor is stopped. It is also possible to prevent noise.

[0029]

As described above, according to the present invention,
The load torque of the compressor is calculated based on the operating state of the refrigerator, the rotation speed of the compressor that generates torque equal to or less than the load torque is calculated, and the compressor is started at the rotation speed. Noise can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of a refrigerator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a more specific circuit configuration of the refrigerator shown in FIG.

FIG. 3 is a flowchart showing the operation of the embodiment shown in FIGS.

FIG. 4 is a flowchart showing the operation of the refrigerator according to another embodiment of the present invention.

FIG. 5 is an explanatory view showing the operation of the embodiment of FIG.

FIG. 6 is a diagram showing a part of a circuit for controlling rotation of a compressor motor.

FIG. 7 is a diagram showing characteristics of a DC motor used as a compressor motor.

[Explanation of symbols]

 1 Refrigerator State Detecting Means 3 Load Torque Calculating Means 5 Comp Starting Speed Controlling Means 7 Comp Speed Changing Controlling Means 9 Refrigerating Controlling Means 11 CPU 31 Compressor

Claims (1)

[Claims] 1. An operating state detecting means for detecting an operating state of a refrigerator, a load torque calculating means for calculating a load torque of a compressor based on the operating state detected by the operating state detecting means, and the load torque calculating means. A rotation speed calculation means for calculating the rotation speed of the compressor that generates a torque equal to or less than the calculated load torque of the compressor, and a starting means for starting the compressor at the rotation speed calculated by the rotation speed calculation means. A refrigerator characterized by having.