JPH07293493A - Fan motor controller - Google Patents

Abstract

PURPOSE:To provide a room fan motor controller which cancels the feed- -back control when impressed voltage of a room fan motor becomes a preset value or lower because of clogging or the like. CONSTITUTION:Electric voltage impressed to a room fan motor 1 is detected by a voltage detecting circuit 6 in order to compare it with a preset value (the lowest operating voltage value) stored by storing part 7 by using a comparing part 8. If the voltage is the lowest operating voltage value or lower, the feed-back control to a room controlling part 3 is cancelled by a cancelling part 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan motor control device for an air conditioner, and more particularly to properly controlling the rotation speed of a fan motor.

[0002]

2. Description of the Related Art Conventionally, rotation speed control of an indoor fan motor of an air conditioner is performed by generating and supplying a voltage corresponding to a target rotation speed by changing the phase angle by phase control.
Changes in the number of revolutions due to fluctuations in the power supply voltage, the temperature of the intake air, exposure to heat exchangers, etc. are detected by the number of revolutions detection circuit consisting of Hall elements incorporated in the fan motor, and the number of revolutions data is sent to the control microcomputer. Phase control is performed by feedback to keep the rotation speed of the fan motor constant. If the rotation speed deviates significantly higher than the target rotation speed, noise due to operating noise becomes a problem, and if the rotation speed deviates to a lower one, problems due to cooling capacity and dew performance 1 occur. In the phase control by feedback, as shown in FIGS. 5 and 6, the “phase angle-rotation speed characteristic” for obtaining the target rotation speed N is operated at A, and the characteristic changes from B to C for some reason. In this case, in order to change the phase angle φa from φb to φc by the feedback control, it is necessary to adjust the control time Ta corresponding to the phase angle to Tb or Tc in the voltage waveform of FIG. However, if a constant rotation speed is maintained by feedback control, for example, if the load applied to the indoor fan motor is extremely reduced due to clogging of the air filter, etc., feedback control suppresses the increase in rotation speed. Make it extremely low. As a result, the amount of air blown into the room is greatly reduced, and a problem occurs when dew condensation occurs on the air outlet.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. When the voltage applied to the indoor fan motor falls below a set value due to clogging or the like, the feedback control is canceled. It is an object of the present invention to provide an indoor fan motor control device that operates.

[0004]

In order to solve the above-mentioned problems, the present invention provides a fan motor control device for an air conditioner, wherein a fan motor is phase-controlled by an indoor unit control section and its rotational speed is feedback-controlled. When a voltage detection circuit that detects the applied voltage of the fan motor, a storage unit that stores a set voltage value, the voltage value detected by the voltage detection circuit and the set voltage value are compared and the former becomes the latter or less,
A comparison unit that outputs a signal, a cancellation unit that cancels feedback control by the output signal of the comparison unit, and an indoor unit control unit that controls each unit, and feedback control when the applied voltage becomes equal to or less than a set voltage value The present invention provides a fan motor control device characterized in that

[0005]

According to the above construction, the voltage applied to the indoor fan motor is detected by the voltage detection circuit and compared with the set voltage value stored in the storage section by the comparison section. The unit cancels the feedback control of the indoor unit control unit.

[0006]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, reference numeral 1 is an AC power supply, which is connected to a phase control circuit 2, and the same phase control circuit 2 is connected to an indoor fan motor 4. The voltage detection circuit 6 is connected to the input terminal of the indoor fan motor 4, and the output of the voltage detection circuit 6 is sent to the indoor unit control unit 3. On the other hand, the indoor fan motor 4 is provided with a rotation speed detection circuit 5, and the output signal of the rotation speed detection circuit 5 is sent to the indoor unit control unit 3. Further, the indoor unit control unit 3 is provided with a storage unit 7 that stores a target rotation speed, a comparison unit 8 that compares the rotation speeds, and a release unit 9 that releases the feedback control. When the air conditioner operates, the indoor unit controller 3 generates a control signal commensurate with the preset target rotation speed and sends it to the phase control circuit 2 to rotate the indoor fan motor 4. Then, the indoor unit controller 3 detects the rotation speed and the voltage detection circuit 6 detected by the rotation speed detection circuit 5.
The control signal is changed on the basis of the change value of the power supply voltage or the like detected in step 1 to perform feedback control of the operation of the indoor fan motor 4 by the phase control circuit 2 to maintain the target rotation speed. On the other hand, the indoor unit control unit 3 compares the set voltage value (minimum operating voltage value) and the target rotation speed with the memory unit 7 and the voltage detected by the voltage detection circuit 6 and the minimum operating voltage value of the memory unit 7. When the former becomes less than the latter, a signal for canceling the feedback control is output.

The control operation of the indoor fan motor in the above configuration will be described with reference to the flowchart of FIG. 2 and FIGS. 3 and 4. As shown in FIG. 3, during normal operation, the indoor fan motor 4 has a phase angle Ta (normal operation value) of the applied voltage waveform.
The indoor fan motor 4 is rotating at the target rotation speed at this time. However, when the air filter is clogged with dust and the load on the indoor fan motor 4 decreases, the rotation speed of the indoor fan motor 4 increases. The rotation speed detection circuit 5 detects the rotation speed and determines whether it is the target rotation speed (step 101). When Y, the voltage is maintained and operation continues. When N, is it lower than the target speed (step 10
2) is determined. When Y, the phase angle is shifted from Ta to T1, the phase control circuit 2 is controlled, the voltage is increased, and the operation is continued. When it is N, the phase angle is shifted from Ta to T2, the phase control circuit 2 is controlled, and the voltage is lowered to maintain the target rotation speed. As for the relationship at this time, as shown in FIG. 4, the normal operation voltage VN (phase angle Ta) is applied to the indoor fan motor 4 to maintain the target rotation speed N, and a predetermined air volume is obtained.

Next, when the air filter is clogged with dust and the load on the indoor fan motor 4 is reduced, the voltage applied to the indoor fan motor 4 is reduced by the feedback control and the target rotational speed N is maintained, so that the air volume becomes a curve. Decrease along.
When the load of the indoor fan motor 4 further decreases and the curve becomes equal to or less than the set value (minimum operating voltage value) VL, it is determined whether the detection voltage ≦ minimum operating voltage value step 103). In the case of N, the feedback control is returned to the original state so as to continue, and in the case of Y, the feedback control is released and the minimum operation voltage is applied to the indoor fan motor 4 to continue the operation. As a result, as shown in FIG. 4, the rotation speed of the indoor fan motor 4 tends to increase, the air volume curve goes from the decreasing direction to the horizontal direction, and the air volume is prevented from decreasing and the air volume is maintained. As another embodiment, the voltage detection circuit 6 detects the phase angle instead of detecting the applied voltage of the indoor fan motor 4, and the storage unit 7 obtains the minimum operation voltage value instead of the minimum operation voltage value. The angle is stored in memory, and the comparison unit 8 compares the detected phase angle with the phase angle during the minimum operation. When the phase angle of the applied voltage becomes equal to or smaller than the phase angle of the storage unit, the output signal is released by the release unit 9 Send to. The cancellation unit 9 cancels the feedback control of the indoor unit control unit 3, and the same effect as described above is obtained.

[0009]

As described above, according to the present invention, when the load applied to the indoor fan motor is extremely reduced due to clogging of the air filter or the like, the feedback control is canceled and the rotation speed of the indoor fan motor is increased. The amount of air flow is increased to prevent condensation on the outlet.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a fan motor control device of the present invention.

FIG. 2 is a flowchart of a fan motor control device of the present invention.

FIG. 3 is a fan motor applied voltage waveform of the fan motor control device of the present invention.

FIG. 4 is a diagram of fan motor applied voltage / revolutions of the fan motor control device of the present invention.

FIG. 5 is a diagram of phase angle / rotation speed of a conventional fan motor control device.

FIG. 6 is a fan motor applied voltage waveform of a conventional fan motor control device.

[Explanation of symbols]

 1 AC power supply 2 Phase control circuit 3 Indoor unit control unit 4 Indoor fan motor 5 Rotation speed detection circuit 6 Voltage detection circuit 7 Storage unit 8 Comparison unit 9 Release unit

Claims (2)

[Claims] 1. A fan motor controller for an air conditioner, wherein a phase of a fan motor is controlled by an indoor unit controller and the number of revolutions of the fan motor is feedback-controlled, and a voltage detection circuit for detecting a voltage applied to the fan motor, and a setting. When the former becomes less than or equal to the latter by comparing the voltage value detected by the storage unit that stores the voltage value and the voltage value detected by the voltage detection circuit and the set voltage value,
A comparison unit that outputs a signal, a cancellation unit that cancels feedback control by the output signal of the comparison unit, and an indoor unit control unit that controls each unit, and feedback control when the applied voltage becomes equal to or less than a set voltage value A fan motor control device characterized by being released. 2. A voltage detection unit for detecting a phase angle of an applied voltage to the fan motor is provided, and a set phase angle is stored in the storage unit, and feedback control is performed when the detected phase angle is less than or equal to the set phase angle. The fan motor control device according to claim 1, wherein the fan motor control device is released.