JP2004150697A - Control method for fan motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for a fan motor preventing frost from dew formation even while adopting a direct current brushless motor with high operation efficiency and little heat generation as the fan motor for circulating cold air in a refrigerator. <P>SOLUTION: The direct current brushless motor is adopted as the fan motor circulating cold air in the refrigerator. During defrosting, an alternating current with a long cycle of, for example, several seconds is supplied to a U phase, a V phase, and a W phase of a coil 11 of the direct current brushless motor in defiance of a signal of a position detecting element. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fan motor operation control method for preventing dew condensation and icing inside a fan motor of a freezer, a refrigerator or the like (hereinafter simply referred to as a refrigerator).
[0002]
[Prior art]
In order to save power consumption of refrigerators, DC brushless motors are often used as fan motors for circulating cool air in the refrigerator.
[0003]
DC brushless motors are characterized by high operating efficiency and very low heat generation.However, moisture condensed during defrosting freezes when the cooling operation resumes, which hinders the operation of the fan motor. In particular, as shown in FIG. 2, when the icing 23 occurs between the rotor 21 and the stator (iron core) 22, the rotor 21 is locked and there is a problem that a failure occurs.
[0004]
[Problems to be solved by the invention]
Although the DC brushless motor has a high operation efficiency and generates very little heat, it generates a small amount of heat due to its operation and is in a state in which dew condensation hardly occurs in normal operation.
[0005]
By the way, when defrosting, when the fan motor is operating, the fan motor is stopped because the heat generated by the defrost circulates inside the refrigerator and causes the temperature inside the refrigerator to rise rapidly.
[0006]
In this state, as time elapses, the temperature inside the refrigerator gradually rises, and when it becomes over-humidified and `` fan motor body temperature ≤ dew point temperature '', dew condensation or dew condensation is likely to occur. However, the operation of the fan motor is hindered, and the rotor is locked when the location of ice formation is between the rotor and the stator (iron core).
[0007]
It is conceivable to attach a heater to the fan motor as a countermeasure against the above-mentioned dew condensation and icing.However, it is not preferable from the viewpoint of saving power consumption. There is a time lag, and there is a problem that even after the power is turned off, the temperature rises due to thermal inertia and it is not possible to perform preferable control.
[0008]
In view of the above problems, the present invention provides a method for controlling a fan motor that does not lead to condensation or icing while employing a DC brushless motor having high operating efficiency and low heat generation as a fan motor for circulating cool air in a refrigerator. The task is to
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention employs a DC brushless motor as a fan motor for circulating cool air in a refrigerator.In the case of defrosting, the current flowing through the winding of the DC brushless motor is reduced to a long-period current. In the switching device (Claim 1), the long-period current is supplied via a 120 ° switching matrix in the DC motor driving device, ignoring the detection signal of the position detecting element (Claim 1). Item 2).
[0010]
According to the present invention having the above-described configuration, a long-period current is applied to the rotor winding of the DC brushless motor from the time of defrosting to the beginning of the restart of the cooling operation to generate heat from the winding (the central portion of the motor). Since the temperature is raised, the effect of preventing dew condensation and ice formation appears immediately, and since the heat is generated from the rotating portion, when the normal operation is started, the rotor rotates and is effectively cooled, so that there is no concern about the rise in the temperature in the refrigerator.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a block diagram of a DC brushless motor.
[0012]
During the normal operation for cooling air circulation in the refrigerator, the DC motor drive unit makes a phase shift of 120 ° as shown in FIG. An alternating current is supplied.
[0013]
When defrosting the inside of the refrigerator, the signal of the position detecting element (not shown) is ignored, and the DC motor is switched to the U phase, V phase, and W phase of the rotor winding 11 of the DC brushless motor, for example, every few seconds. An alternating current is supplied through a 120 ° switching matrix provided in the drive device to generate heat from the rotor winding 11 to prevent condensation.
[0014]
【The invention's effect】
As described above, according to the present invention, a long-period current is applied to the rotor winding of the DC brushless motor from the time of defrosting to the beginning of the restart of the cooling operation, so that the current flows from the rotor winding (the central part of the motor). Heat generation and temperature increase effectively prevent condensation and icing. In addition, since the heat is generated from the rotating part, when the normal operation is started, the rotor is rapidly cooled by the rotation of the rotor and does not affect the refrigeration efficiency of the refrigerator.
[Brief description of the drawings]
FIG. 1A is a block diagram of a DC brushless motor employing the method of the present invention. FIG. 1B is an alternating current application diagram. FIG. 2 is an explanatory diagram of condensation and icing in a conventional fan motor for circulating cool air in a refrigerator. ]
11 Winding 21 Rotor (rotor)
22 Iron core (stator)
23 Condensation (freezing)

Claims (2)

A fan motor that uses a DC brushless motor as the fan motor that circulates cool air in a refrigerator, and switches the current flowing through the winding of the DC brushless motor to a long-period current during defrosting. Control method. 2. The method according to claim 1, wherein the long-period current is supplied via a 120.degree. Switching matrix in the DC motor drive, ignoring the detection signal of the position detecting element. .

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