JP3540574B2 - Refrigerator abnormality detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality detector capable of securely detecting and alarming falling-off of a fan from the fan motor in a refrigerator including the fan motor. SOLUTION: There is provided revolution number detection means for detecting the number of revolutions of a fan motor 17. There is further provided current detection means for detecting a current flowing through the fan motor 17. There is provided alarming means. When there is continued for a predetermined time interval the state where the number of revolutions of the fan motor 17 is a set one and applied voltage is lower than set voltage set in response to the set number of revolutions, the number of revolutions of the fan motor 17 is changed, and a change in the current value at that time is detected based upon an output of the current value detection means. When the change in the current value is smaller than a predetermined value, failure is judged and the alarming means is actuated.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigerator abnormality detection device including a control device that controls a rotation speed by adjusting a voltage applied to a fan motor.
[0002]
[Prior art]
Conventionally, in a home refrigerator of this type, as disclosed in, for example, Japanese Patent Application Laid-Open No. 8-247606 (F25D17 / 06), a freezing room, a refrigerating room, a vegetable room, and the like are formed in a heat insulating box body. Cool air from a cooler provided on the back is circulated and cooled in each room by an internal fan (cool air circulation blower) driven by a fan motor.
[0003]
Further, a machine room is formed below the heat insulating box, and a compressor and a condenser which constitute a refrigerant circuit together with the cooler are installed in the machine room. A machine room fan (condenser blower) driven by a fan motor for air-cooling the compressor and the condenser is also installed in the machine room.
[0004]
In recent years, the voltage applied to the fan motor of the fan in the refrigerator is adjusted based on the temperature in each room, or the voltage applied to the fan motor of the machine room fan is adjusted based on the temperature of the condenser or the compressor. Refrigerators have also been developed that can control the rotation speed of each fan motor to achieve appropriate cooling air circulation or air cooling according to each temperature, or that can control the rotation speed constantly even when the load fluctuates. ing.
[0005]
[Problems to be solved by the invention]
By the way, these in-compartment fans and machine room fans are fixed to the rotation shaft of each fan motor by a spring or the like. There was a case that it dropped off from the rotating shaft.
[0006]
If the fan in the refrigerator or the machine room fan falls off, the cool air is not circulated in the refrigerator, and the air cooling of the condenser and the compressor is impaired, so that the cooling capacity in the refrigerator is remarkably reduced. Therefore, conventionally, it has been attempted to detect such an abnormality only by the operating current of the fan motor. This is to detect a decrease in the energizing current due to a decrease in the load due to the fan dropping, and to judge the abnormality. However, since the load fluctuation is caused by various other factors, an accurate judgment is made. It was difficult.
[0007]
The present invention has been made in order to solve the conventional technical problem, and in a refrigerator having a fan motor, an abnormality detection that can reliably detect and report the dropout of the fan from the fan motor. It is intended to provide a device.
[0008]
[Means for Solving the Problems]
The abnormality detection device according to the present invention includes a fan motor, and a control device that performs a rotation speed control by adjusting a voltage applied to the fan motor. The control device includes a current value flowing through the fan motor. Current value detecting means for detecting the rotation speed of the fan motor, a rotation speed detecting means for detecting the rotation speed of the fan motor, and a notifying means, wherein the rotation speed of the fan motor is a set rotation speed and the applied voltage is in accordance with the set rotation speed. When the state lower than the set voltage is set for a certain period of time, the rotation speed of the fan motor is changed, and the change in the current value in that case is detected based on the output of the current value detection means, and the current value of the current value is detected. When the change is smaller than a certain value, it is determined that the abnormality is abnormal, and an abnormality detection operation for operating the notification means is performed.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an electric circuit diagram of the refrigerator of the present invention, and FIGS. 2 and 3 are flowcharts showing programs of a microcomputer attached to the refrigerator of the present invention.
[0010]
In FIG. 1, reference numeral 2 denotes a general-purpose microcomputer constituting the control device 1 of the refrigerator. The microcomputer 2 includes a fan motor drive circuit 31, a machine room fan motor drive circuit 32, and an alarm circuit 33. It is connected. In the internal fan motor drive circuit 31, a PWM (pulse width modulation) output port of the microcomputer 2 is connected to the base of the transistor 7 via the resistor 3. The emitter of the transistor 7 is grounded, the collector is connected to the base of the transistor 8 via the resistor 4, and the emitter of the transistor 8 is connected to a DC + 16.5V power supply.
[0011]
The collector of the transistor 8 is connected to one terminal of the fan motor 17 via the forward diode 12 and the coil L1. A capacitor 10 is connected between the coil L1 and the ground, and the coil L1 and the capacitor 10 form a smoothing circuit. A surge absorbing diode 13 is connected between the diode 12 and the coil L1 and between the ground.
[0012]
The fan motor 17 is composed of a DC motor and drives a fan in the refrigerator (not shown) that circulates cool air in the refrigerator. The in-compartment fan includes the fan motor 17 and a fan fixed to a rotating shaft of the fan motor 17 by a spring or the like. The fan motor 17 has a built-in Hall IC serving as rotation speed detecting means, and the output of the Hall IC is connected to the base of the transistor 9 via the resistor 5. The emitter of this transistor 9 is grounded, and the collector is connected via a resistor 6 to a DC +5 V power supply. The collector and the resistor 6 are connected to a rotation speed input port of the microcomputer 2.
[0013]
The Hall IC generates an output corresponding to the rotation speed of the fan motor 17 and turns on / off the transistor 9 to input the rotation speed of the fan motor 17 to the rotation speed input port of the microcomputer 2. The other terminal of the fan motor 17 is grounded via a resistor 18 as small as about 10 ohms.
[0014]
The machine room fan motor drive circuit 32 has the same circuit configuration as the in-compartment fan motor drive circuit 31. That is, in the machine room fan motor drive circuit 32, another PWM (pulse width modulation) output port of the microcomputer 2 is connected to the base of the transistor 7A via the resistor 3A. The emitter of the transistor 7A is grounded, the collector is connected to the base of the transistor 8A via the resistor 4A, and the emitter of the transistor 8A is connected to a DC + 16.5V power supply.
[0015]
The collector of the transistor 8A is connected to one terminal of a fan motor 17A via a forward diode 12A and a coil L1A. A capacitor 10A is connected between the coil L1A and the ground, and the coil L1A and the capacitor 10A form a smoothing circuit. A surge absorbing diode 13A is connected between the diode 12A and the coil L1A and between the ground.
[0016]
The fan motor 17A is also formed of a DC motor, and circulates air in a machine room of a refrigerator (not shown) and drives a machine room fan for cooling a compressor and a condenser of a cooling device (not shown). The machine room fan includes the fan motor 17A and a fan fixed to a rotating shaft of the fan motor 17A by a spring or the like. The fan motor 17A also has a built-in Hall IC serving as rotation speed detecting means, and the output of the Hall IC is connected to the base of a transistor 9A via a resistor 5A. The emitter of this transistor 9A is grounded, and the collector is connected to a DC + 5V power supply via a resistor 6A. The collector and the resistor 6A are connected to another rotation speed input port of the microcomputer 2.
[0017]
The Hall IC generates an output according to the rotation speed of the fan motor 17A, and turns on / off the transistor 9A to input the rotation speed of the fan motor 17A to the rotation speed input port of the microcomputer 2. The other terminal of the fan motor 17A is also grounded via the resistor 18. That is, the resistor 18 is configured to flow a current in which the currents flowing through the two fan motors 17 and 17A are combined.
[0018]
The voltage between the fan motors 17 and 17A and the resistor 18 is connected to the plus input terminal of the OP amplifier 14, and the minus input terminal of the OP amplifier 14 is grounded via the resistor 19. A negative feedback resistor 16 is connected between the output of the OP amplifier 14 and the negative input terminal, and the output of the OP amplifier 14 is connected to an A / D (analog / digital) conversion input port of the microcomputer 2. .
[0019]
As described above, since the total current of the two fan motors 17 and 17A flows through the resistor 18, a voltage proportional to the total current value is amplified by the OP amplifier 14 and input to the A / D conversion input port of the microcomputer 2. Configuration.
[0020]
The alarm output port of the microcomputer 2 is connected to the base of a transistor 22 via a resistor 20, and the emitter of the transistor 22 is grounded. The collector of the transistor 22 is connected via a resistor 21 to one end of an alarm device 23 composed of an LED as an alarm means, and the other end of the alarm device 23 is connected to a DC + 5V power supply. The alarm device 33, the transistor 22, and the resistors 20, 21 constitute the alarm circuit 33.
[0021]
The microcomputer 2 generates an output from each of the PWM output ports, and controls ON / OFF of the transistor 8 or 8A via the transistor 7 or 7A. In this case, the fan motors 17 and 17A are turned ON and OFF by issuing ON and OFF commands in synchronization with ON / OFF of the compressor based on the temperature of the refrigerator (not shown). Is also turned off when is opened. The transistors 8 and 8A output a pulse having a width corresponding to the ON time, and the pulse is smoothed by the coil L1 (L1A) and the capacitor 10 (10A) and applied to each fan motor 17 or 17A.
[0022]
The microcomputer 2 changes the voltage applied to each fan motor 17, 17A by changing the ON time of the transistor 8 or 8A, that is, the pulse width, thereby changing the rotation speed of the fan motor 17, 17A. It is to adjust.
[0023]
Next, control of the number of revolutions of the fan motor 17 of the internal fan motor drive circuit 31 by the microcomputer 2 will be described with reference to FIG. Since the rotation speed control of the fan motor 17A of the machine room fan motor drive circuit 32 is the same, the description is omitted. Further, it is assumed that the microcomputer 2 has a preset rotation number of the in-compartment fan motor 17 (in this case, the fan motor 17A may be set).
[0024]
The microcomputer 2 determines in step S1 whether an operation (ON) command for the fan motor 17 has been issued, and if the operation command has been issued and the fan motor 17 is operating, sets a certain time in step S2. Proceed to step S3.
[0025]
In step S3, the microcomputer 2 determines whether or not the fixed time set in step S2 has elapsed. If the fixed time has not elapsed, the microcomputer 2 repeats step S3 and waits. When the predetermined time has elapsed in step S3, the process proceeds to step S4, where the microcomputer 2 determines that the rotation speed of the fan motor 17 input to the rotation speed input port as described above is equal to the preset rotation speed. It is determined whether or not the rotation speeds are equal, and if the rotation speed is the set rotation speed, the process returns to step S2.
[0026]
If the rotation speed of the fan motor 17 is different from the set rotation speed in step S4, the process proceeds to step S5, and it is determined whether the rotation speed of the fan motor 17 is higher than the set rotation speed. If it is higher than the set rotation speed, the process proceeds to step S6. Therefore, the microcomputer 2 subtracts the set number of revolutions from the current number of revolutions of the fan motor 17 input to the number of revolutions input port and divides the result by a predetermined ratio A. After the conversion to ΔV, the process proceeds to step S7.
[0027]
Here, the microcomputer 2 changes the rotation speed of the fan motor 17 in a predetermined number of steps. In the conversion in step S6, if the difference between the rotation speeds is small, the calculation result is smaller than 1. , ΔV is determined to be 0. Therefore, in step S7, the microcomputer 2 determines whether or not the calculation result in step S6 is 0. If the calculation result is 0, the microcomputer 2 proceeds to step S8, sets ΔV to 1 (step), and proceeds to step S9. If it is not 0 in step S7, the process proceeds directly to step S9.
[0028]
In step S9, the microcomputer 2 determines a value obtained by subtracting the calculation result ΔV in step S6 or step S8 from the voltage currently applied to the fan motor 17 as the voltage to be applied to the fan motor 17. Based on this determination, the microcomputer 2 reduces the voltage applied to the fan motor 17 and reduces the rotation speed by reducing the pulse width.
[0029]
On the other hand, when the rotation speed of the fan motor 17 is lower than the set rotation speed, the process proceeds from step S5 to step S10. Therefore, the microcomputer 2 subtracts the current rotation speed of the fan motor 17 input to the rotation speed input port from the set rotation speed, similarly divides the ratio by the ratio A, and determines the difference between the rotation speeds as the number of voltage change steps ΔV After that, the process proceeds to step S11.
[0030]
In step S11, the microcomputer 2 determines whether or not the calculation result in step S10 is 0. If the calculation result is 0, the microcomputer 2 proceeds to step S12, sets ΔV to 1 (step) as described above, and proceeds to step S13. If it is not 0 in step S11, the process directly proceeds to step S13.
[0031]
Then, in step S13, the microcomputer 2 determines a value obtained by adding the calculation result ΔV of step S10 or step S12 to the voltage currently applied to the fan motor 17 as the voltage to be applied to the fan motor 17. The microcomputer 2 increases the voltage applied to the fan motor 17 by increasing the pulse width based on this determination, thereby increasing the rotation speed.
[0032]
After the processing in step S9 or step S13, the microcomputer 2 returns to step S2, sets a fixed time again, waits in step S3, and then executes the rotation speed adjustment in step S4 and thereafter.
[0033]
Note that the machine room fan motor 17A of the machine room fan motor drive circuit 32 is also controlled in the same manner as the in-compartment fan motor drive circuit 31, but in this case, the determination in step S4 is based on the setting rotation of the machine room fan motor 17A. The numbers are of interest.
[0034]
The means (Hall IC) for detecting the number of revolutions of the fan motor 17 (17A) is provided, and the microcomputer 2 controls the number of revolutions of the fan motor 17 to the set number of revolutions based on the number of revolutions output from the Hall IC. Therefore, even if the load applied to the fan motor 17 fluctuates, the set rotation speed can be maintained.
[0035]
In particular, since the microcomputer 2 repeats the adjustment of the rotation speed of the fan motor 17 (17A) at a constant cycle (constant time), the microcomputer 2 starts the adjustment at a stage where the rotation speed is stabilized after the fan motor 17 is started, and thereafter, Is also adjusted at a constant cycle. Thus, the operation of the fan motor 17 can be stabilized.
[0036]
Next, the operation of the microcomputer 2 for detecting an abnormality of the internal fan will be described with reference to FIG. Since the same applies to the fan motor 17A of the machine room fan, the description is omitted. Further, it is assumed that the applied voltage when the fan is attached to each of the fan motors 17 and 17A and rotates at the set rotation speed is stored in the microcomputer 2 in advance as the set voltage PV.
[0037]
The microcomputer 2 determines in step S21 whether an operation (ON) command for the fan motor 17 has been issued. If yes, the process proceeds to step S22. If not, the microcomputer 2 sets the PV to the set voltage in step S32. Set as On the other hand, in step S22, it is determined whether or not the fan motor 17 is rotating at the set rotation speed. If the fan motor 17 is rotating at the set rotation speed, the process proceeds to step S23. If the fan motor 17 is not rotating at the set rotation speed in step S22, step S22 is repeated.
[0038]
In step S23, the microcomputer 2 determines from the output generated from the PWM output port whether or not the voltage (current voltage in the drawing) currently applied to the fan motor 17 is smaller than the set voltage PV. If the current voltage is smaller than the set voltage PV, the process proceeds to step S24, where a predetermined time (in this case, 10 seconds) is set in a timer (not shown), and the process proceeds to step S25. If the current voltage is equal to or higher than the set voltage PV in step S23, step S23 is repeated.
[0039]
Next, in step S23, it is determined whether or not the predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step S23. That is, steps S23, S24, and S25 are repeated to determine whether the state in which the current voltage is lower than the set voltage PV has continued for a predetermined time.
[0040]
If the predetermined time has elapsed in step S25, the microcomputer 2 detects the total current of the two fan motors 17 and 17A amplified by the OP amplifier 14 and input to the A / D conversion input port of the microcomputer 2 in step S26. And store it in the memory M. That is, in step S26, the current total current of both fan motors 17 and 17A is detected, stored as the current value in the memory M, and the process proceeds to step S27.
[0041]
In step S27, the microcomputer 2 changes the voltage applied to the fan motor 17 by changing the ON time (pulse width) of the transistor 8 generated from the PWM output port. In this case, the rotation speed of the fan motor 17 is changed by plus 200 rotations or minus 200 rotations, and the process proceeds to step S28. In step S28, the microcomputer 2 stores the current value (current value after the rotation speed change) flowing through both fan motors 17 and 17A into the memory M when the rotation speed of the fan motor 17 is changed by 200 rotations or 200 rotations respectively. Is stored as the deviation ΔA, and the process proceeds to step S29.
[0042]
Here, if the fan motor 17 is changed to plus 200 rotations or minus 200 rotations, the load fluctuates during normal operation because the fan blows air, and a predetermined current change occurs. On the other hand, when the fan of the fan motor 17 is dropped off, even if the rotation is changed by plus 200 rotations or minus 200 rotations, the air is not blown by the fan, so that the load variation is small and the current value also varies little. Disappears. That is, the deviation ΔA becomes smaller.
[0043]
Based on the above, the microcomputer 2 determines whether or not the deviation ΔA is smaller than the set value in step S29. If smaller, the microcomputer 2 determines that the fan of the fan motor 17 has dropped out and proceeds to step S30. Then, in step S30, the alarm device 23 (LED) is flickered and the dropped fan motor 17 is stopped, and the process proceeds to the subsequent steps.
[0044]
If the deviation ΔA is not smaller than the set value in step S29 (the above case), the microcomputer 2 proceeds to step S31 to make a change by subtracting one step voltage from the set voltage PV, and sets the changed value as the set voltage PV. It memorizes and returns to step S23. That is, if it is determined in step S29 that the fan of the fan motor 17 has not fallen off, the load is reduced due to softening of the grease of the motor and the like, and it is determined that the applied voltage is reduced, and the set voltage PV is reduced. It is to be corrected.
[0045]
As described above, the falling-off of the fan from the fan motor 17A can be similarly detected for the machine room fan. Therefore, in the case of the present invention, any of the fan motors can be used in a refrigerator having two fan motors as in the embodiment. It is possible to quickly and accurately detect whether or not the fan has dropped out of the device.
[0046]
Also in this case, since only one OP amplifier 14 is required, the cost is low.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, the control device includes: a current value detection unit that detects a current value flowing through the fan motor; a rotation speed detection unit that detects a rotation speed of the fan motor; and a notification unit. When the rotation speed of the fan motor is the set rotation speed and the applied voltage is lower than the set voltage set according to the set rotation speed for a certain period of time, the rotation speed of the fan motor is changed, and The change of the current value in the case is detected based on the output of the current value detection means, and when the change of the current value is smaller than a certain value, it is determined that the current value is abnormal, and an abnormality detection operation for operating the notification means is performed. As a result, it is possible to eliminate temporary changes due to the influence of ambient temperature, etc., accurately detect and judge the dropout of the fan from the fan motor, and to notify by the notification means. That.
[Brief description of the drawings]
FIG. 1 is an electric circuit diagram of a control device of a refrigerator according to the present invention.
FIG. 2 is a flowchart showing a program of a microcomputer attached to the refrigerator of the present invention.
FIG. 3 is a flowchart showing a program of an abnormality detecting operation of a microcomputer attached to the refrigerator of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 control device 2 microcomputer 3 resistor 4 resistor 5 resistor 6 resistor 7 transistor 8 transistor 9 transistor 10 capacitor 12 diode 13 diode 14 OP amplifier 16 resistor 17 fan motor 17A fan motor 18 resistor 19 resistor 20 resistor 21 resistor 22 transistor 23 alarm device 31 Internal fan motor drive circuit 32 Machine room fan motor drive circuit 33 Alarm circuit

Claims (1)

A refrigerator including a fan motor and a control device that adjusts a voltage applied to the fan motor and executes a rotation speed control,
The control device includes a current value detection unit that detects a current value flowing through the fan motor, a rotation speed detection unit that detects a rotation speed of the fan motor, and a notification unit, and the rotation speed of the fan motor is set. When a certain period of time has elapsed since the rotation speed and the applied voltage is lower than the set voltage set according to the set rotation speed, the rotation speed of the fan motor is changed, and the change in the current value in that case is changed. Detecting the current value based on the output of the current value detection means, determining that the change in the current value is smaller than a predetermined value is abnormal, and performing an abnormality detection operation for operating the notification means. Refrigerator abnormality detection device.

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