JPH02282646A - Outdoor unit of air conditioner - Google Patents

Abstract

PURPOSE:To always perform a stable heat exchange in response to changes in the wind direction and velocity of natural wind by picking up as electrical signals the rotation of the fan motor due to the natural wind while said fan motor is not being electrified so as to find the direction of rotation of the fan motor based on the signals, and operating the fan motor in either normal or reverse direction based on the finding. CONSTITUTION:When the fan motor 3 is rotated due to the natural wind outdoors while said fan motor 3 is not being electrified such as before the air conditioner startup or during the operation suspension on account of the thermostat or during the defrosting operation, etc., the signal detection circuit 9 detects the induced voltage by the fan motor 3 and the normal/reverse rotation determining circuit 8 determines the direction of the rotation. If the rotation is reverse, a control signal is transmitted to the normal/reverse switching circuit 10 to switch said circuit 10, which maintains the switched position to switch the normal rotation command signal from an inverter control circuit 7 to the reverse rotation command signal, which is then transmitted to an inverter circuit 5 to reverse the rotation of the fan motor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an outdoor unit of an air conditioner, and more particularly to control of the rotation direction and rotation speed of a fan motor that cools an outdoor heat exchanger.

[Prior art] In addition to the compressor, the outdoor unit of an air conditioner is equipped with an outdoor heat exchanger, a fan motor, etc., and the outdoor heat exchanger is cooled by the fan motor. As the fan motor, a capacitor-start induction type is widely used.

[Problem to be solved by the invention]

In the case of the above-mentioned fan motor, not only the direction of rotation of the fan motor but also the number of revolutions is almost constant, and depending on conditions such as the installation location of the outdoor unit, the natural wind on the fan motor blades may change depending on the season and day. When the direction and strength change, especially when the wind is facing the fan, the amount of air discharged by the fan motor decreases, making it impossible to obtain the specified wind speed, reducing the heat exchange rate of the outdoor heat exchanger, and reducing efficiency. They are often forced to drive poorly.

For example, the blowing wind speed (3,
If a headwind blows at almost the same wind speed (3 to 4 m/s), the air volume may decrease by about 30%.

In addition, a short circuit phenomenon occurs in which warmed air discharged by the fan motor circulates again to the air intake side, and the heat exchange rate may decrease.

Therefore, the present invention solves these problems,
The aim is to provide an outdoor unit for air conditioners that can constantly exchange heat in a stable manner, even in response to changes in natural wind direction and wind speed.

[Means to solve the problem]

The present invention has been made to solve the above-mentioned problems, and is an outdoor unit of an air conditioner equipped with a fan motor rotationally driven by an inverter circuit, in which the fan motor is rotated by natural wind when the fan motor is not energized. A configuration in which the fan motor is extracted as an electrical signal, the rotation direction of the fan motor is determined based on the electrical signal, and the fan motor is rotated forward or reverse based on the determination result, that is, when the fan motor is not energized. A signal detection circuit that extracts the rotation caused by the natural wind as an electrical signal, a forward/reverse determination circuit that determines the rotation direction of the fan motor based on the output signal from the signal detection circuit, and a forward/reverse rotation determination circuit. and a forward/reverse rotation switching circuit that switches a forward rotation command signal sent from the inverter control circuit to the inverter circuit to a reverse rotation command signal in response to a control signal sent to the inverter circuit.

[Effect]

According to the above configuration, when the fan motor rotates due to outdoor natural wind while the fan motor is in a non-energized state, such as before the air conditioner starts operating, during thermostat operation, or during defrosting, a signal is generated. The detection circuit detects the induced voltage of the fan motor, and the forward/reverse determination circuit determines the rotation direction. When the rotation direction is reverse, a control signal is sent to the forward/reverse switching circuit to switch the same. The switching circuit can maintain the switched state and switch the forward rotation command signal from the inverter control circuit to a reverse rotation command signal and send it to the inverter circuit to cause the fan motor to rotate in the reverse direction.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is a perspective view of an outdoor unit of an air conditioner, in which 1 is the outdoor unit body, 2 is an outdoor heat exchanger, and 3 is a fan motor having blades 3a.

FIG. 2 is a block diagram of a fan motor control circuit that controls the rotation speed and rotation direction of the fan motor 3.

In FIG. 2, 3 is the aforementioned fan motor, 4 is a commercial power source, 5 is a converter circuit that converts AC power from the commercial power source 4 into DC power, and 6 is a converter circuit that takes in DC power from the converter circuit to drive the fan motor 3. 7 is an inverter control circuit that sends out a forward rotation command signal (base drive signal) that drives the inverter circuit 6 based on a serial signal sent from the indoor unit (not shown), and 8 is an inverter circuit that drives the rotation. A forward/reverse switching circuit 9 is interposed between the control circuit 7 and the inverter circuit 6 and switches a forward rotation command signal from the inverter control circuit 7 to a reverse rotation command signal. A signal detection circuit 10 detects electric signals generated from three Hall elements (not shown) included in the fan motor 3, and a signal detection circuit 10 detects electric signals generated by the fan motor 3 based on an output signal from the signal detection circuit 9. A forward/reverse determination circuit 11 determines the rotation direction of the motor 3, which compares a control signal sent from the forward/reverse determination circuit with a predetermined reference voltage, and sends a forward/reverse switching signal to the forward/reverse switching circuit 8. This is a comparison circuit.

The circuit configuration for controlling the rotation speed and rotation direction of the fan motor 3 has been described above, and the circuit operation will be explained below.

The method of controlling the rotation speed of the fan motor 3 using the inverter circuit 6, the inverter control circuit 7, etc. is not particularly different from the method conventionally used for controlling the rotation speed of the compressor of an air conditioner. The explanation is omitted,
Here, switching of the rotation direction will be mainly explained.

If the blades 3a rotate due to outdoor natural wind while the fan motor (DC motor) 3 is in a de-energized state, such as before starting operation of the air conditioner, during thermostat operation, or during defrosting, the blades 3a may rotate. Rotor (permanent magnet) directly connected to the rotating shaft
rotates, generating an electromotive force in the coil, and the fan motor 3
Electric signals corresponding to the rotational speed and direction of the blade 3a are sequentially sent out from three Hall elements (not shown) arranged in the blade 3a.

The signal detection circuit 9 detects electrical signals sequentially obtained from the three Hall elements.

The forward/reverse determination circuit IO determines the rotation direction of the fan motor 3 based on the electrical signals from at least two adjacent Hall elements among the electrical signals sequentially sent from the signal detection circuit 9 in the previous stage, and determines the rotation direction of the fan motor 3 if the determination result is reverse. In the case of rotation, a signal voltage corresponding to the rotation speed is sent out.

In the comparator circuit 11, a preset reference voltage, for example, a voltage approximately equal to the signal voltage output from the forward/reverse determination circuit 10 when the back wind against the fan motor 3 is 1 m/s, is set as the reference voltage, The signal voltage output from the forward/reverse determination circuit 10 to the comparison circuit 11 is compared, and if it is higher than the reference voltage, a forward/reverse switching signal is sent out.

In the forward/reverse switching circuit 8, for example, the head wind is 1 m.
/s or less, and if a forward/reverse switching signal is not applied in advance by the comparison circuit 11, the forward rotation command signal sent from the inverter control circuit 7 is sent out as it is as the base drive signal of the inverter circuit 6.

When the head wind exceeds l m/s and a forward/reverse switching signal is applied in advance from the comparator circuit 11, the output circuit in the forward/reverse switching circuit 8 remains switched, so that inverter control is performed. The forward rotation command signal sent from the circuit 7 is also inverted to become a reverse rotation command signal, and this reverse rotation command signal is sent as the base drive signal of the inverter circuit 6.

The inverter circuit 6 is operated by either the forward rotation command signal or the reverse rotation command signal, and the fan motor 3 rotates forward in response to the former signal and reversely rotates in response to the latter signal.

As explained above, the present invention provides the blades 3 of the fan motor 3.
The rotation direction of the fan motor 3 can be automatically switched and controlled in accordance with the direction and strength of the natural wind relative to a.

Incidentally, the inverter control circuit 7 cuts off the control signal to the signal detection circuit 9 at the same time or immediately before sending out the forward rotation command signal, and controls the fan motor 3 of the signal detection circuit 9.
The electric signal input end (not shown) of the fan motor 3 is opened to prevent the signal detection circuit 9 from being damaged by the electromotive force generated when the fan motor 3 rotates at high speed.

In addition, when the forward rotation command signal from the inverter control circuit 7 is stopped due to the air conditioner stopping operation or thermostat operation, a control signal is sent to the signal detection circuit 9, but the timing of this sending is is not immediately after the stop of the forward rotation command signal, but after a predetermined period of time has elapsed.

The reason for this is that even if the forward rotation command signal is stopped, the fan motor 3 continues to rotate for a predetermined time due to inertia, so it is impossible to distinguish it from rotation caused by natural wind, and accurate information about natural wind cannot be obtained. It's to get it.

〔Effect of the invention〕

With an outdoor unit that has a fan motor control circuit as explained above, the rotation speed of the fan motor can be controlled according to the operating conditions, and the outdoor natural wind against the fan motor can be In some cases, such as when an air conditioner stops operating or when the thermostat is activated, the direction of rotation of the fan motor can be reversed based on information obtained from the fan motor in advance, such as when rotating against a headwind. This eliminates the occurrence of a short circuit phenomenon in which the air volume decreases or the exhausted air is re-inhaled, the heat exchange efficiency of the outdoor heat exchanger improves, and there is no need to waste electricity.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an outdoor unit of an air conditioner showing an embodiment of the present invention, and FIG. 2 is a block diagram of a control circuit that controls the rotation speed and rotation direction of a fan motor of the outdoor unit. In the figure, 1 - outdoor unit main body, 2 - outdoor heat exchanger,
3---Fan motor, 3a---Blade, 4---
Commercial power supply, 5. Converter circuit, 6. Inverter circuit, 7. Inverter control circuit, 8..- Forward/reverse switching circuit, 9. Signal detection circuit, to- Forward/reverse determination circuit, 1.
1- Comparison circuit.

Claims (4)

[Claims] (1) In an outdoor unit of an air conditioner equipped with a fan motor rotationally driven by an inverter circuit, the rotation caused by natural wind when the fan motor is not energized is extracted as an electric signal, and the fan motor is controlled based on the electric signal. An outdoor unit of an air conditioner, characterized in that the direction of rotation of the fan motor is determined, and the fan motor is rotated forward or backward based on the determination result. (2) A signal detection circuit that extracts the rotation caused by natural wind when the fan motor is not energized as an electrical signal, and a forward/reverse determination circuit that determines the rotation direction of the fan motor based on the output signal from the signal detection circuit. and a forward/reverse switching circuit that switches a forward rotation command signal sent to the inverter circuit from the inverter control circuit to a reverse rotation command signal in response to a control signal sent from the same stop/reverse determination circuit. 2. The outdoor unit of an air conditioner according to claim 1, wherein the fan motor is made to rotate in reverse. (3) A comparison circuit for comparing the control signal sent from the forward/reverse determining circuit with a predetermined reference voltage is interposed between the forward/reverse determining circuit and the forward/reverse switching circuit, and 2. The outdoor unit of an air conditioner according to claim 1, wherein when the strength of the head wind is greater than a predetermined strength, the forward/reverse switching circuit is switched by a forward/reverse switching signal from the comparison circuit to cause the fan motor to rotate in the reverse direction. (4) The outdoor unit of an air conditioner according to claim 1, wherein the electric signal is a voltage obtained from a plurality of Hall elements that detect rotation of a rotor.