CN101245944A - Air conditioner and its control method - Google Patents

Abstract

According to the air conditioner provided by the present invention, it includes: a fan; an asynchronous motor including a rotor that rotates the fan, a main coil that flows in current from a single-phase power source to rotate the rotor, and an auxiliary motor for starting the rotor. a coil and a capacitor for generating a phase difference between the main coil and the auxiliary coil; a phase detection unit for detecting the phase of the main coil and the auxiliary coil; a control unit for acting as the phase detection unit When the detected phase difference between the main coil and the auxiliary coil is smaller than a reference value, the asynchronous motor is controlled to stop the rotation of the fan. Therefore, since the presence or absence of failure is directly detected using the phase difference between the main coil and the auxiliary coil of the fan motor, unnecessary power consumption can be prevented.

Description

Air conditioner and its control method

technical field

The present invention relates to an air conditioner and its control method, more specifically, to an air conditioner with a fan motor working with a single-phase asynchronous motor and its control method.

Background technique

Generally, an air conditioner such as an air conditioner uses a fan motor implemented as a single-phase asynchronous motor for taking in/discharging outside air. A conventional air conditioner employs the following method to identify a fan motor failure.

For example, when the temperature of the outdoor unit during cooling operation remains higher than a predetermined temperature for a long time or the temperature difference between the outdoor temperature and the outdoor unit during heating operation is greater than a certain temperature, it is determined whether the fan motor is faulty. At this time, in order to determine whether the fan motor fails, the compressor is turned off after the cooling compressor runs for a predetermined time when the cooling operation is in operation; and the compressor is turned off after the heating compressor runs for a predetermined time when the heating operation is in operation. Then, a fan abnormality signal of the outdoor unit is sent to the indoor unit, and the indoor and outdoor units are stopped.

If the fans included in the indoor and outdoor units stop due to the stop of the indoor and outdoor units, an overcurrent flows through the intelligent power module (IPM), causing the compressor to stop, and the indoor and outdoor units are restarted after a few minutes. At this time, if the stop state of the fan is detected all the time, an error message will be displayed and the work of the indoor and outdoor units will be stopped.

This indirect detection method judges whether the fan is limited by using indirect methods such as outdoor temperature, outdoor unit temperature, compressor motor current, etc., and since the current rises when the fan stops, putting pressure on each power element may shorten the life of the element and cause cause unnecessary power consumption.

In addition, the traditional indirect detection method still has the problem of being unable to distinguish whether it is a fan motor failure or a failure of other circuit parts.

Contents of the invention

An object of the present invention is to provide an air conditioner and a control method thereof that prevent unnecessary power consumption by directly detecting whether a failure occurs using a phase difference between a main coil and an auxiliary coil of a fan motor.

In order to achieve the above object, the air conditioner provided according to the present invention includes: a fan; an asynchronous motor, the asynchronous motor includes a rotor that rotates the fan, a main coil that flows in current from a single-phase power supply to rotate the rotor, and is used to start The auxiliary coil of the rotor and a capacitor for generating a phase difference between the main coil and the auxiliary coil; a phase detection unit for detecting the phase of the main coil and the auxiliary coil; a control unit for detecting the phase of the main coil and the auxiliary coil; When the phase difference between the main coil and the auxiliary coil detected by the phase detection unit is smaller than a reference value, the asynchronous motor is controlled to stop rotation of the fan.

Here, the reference value is preferably 90 degrees.

Also, the phase detection unit may further include a first phase detection unit that detects the phase of the main coil and a second phase detection unit that detects the phase of the auxiliary coil.

In addition, the control unit may further include a zero-cross circuit.

Also, the control section includes a power supply section that supplies power to the system, and turns off the power supply section when a phase difference between the main coil and the auxiliary coil is smaller than the reference value.

In addition, in order to achieve the above object, according to the control method of the air conditioner provided by the present invention, the air conditioner includes a fan and a rotor that rotates the fan, a main coil that obtains current from a single-phase power source to rotate the rotor, and In an asynchronous motor for starting an auxiliary coil of the rotor and a capacitor for generating a phase difference between the main coil and the auxiliary coil, the method includes the step of: comparing whether the phase difference between the main coil and the auxiliary coil is is less than a reference value; when the phase difference is less than a reference value, stop the rotation of the fan. .

Here, the reference value is preferably 90 degrees.

Furthermore, the step of comparing whether the phase difference between the main coil and the auxiliary coil is smaller than a reference value further includes the step of determining a zero-cross point position according to the current induced by the main coil and the auxiliary coil.

In addition, it further includes the step of cutting off the power supply to the system when the phase difference is smaller than the reference value.

Description of drawings

Fig. 1 is the control block diagram of the air conditioner provided according to the present invention;

2a and 2b are schematic diagrams showing a single-phase asynchronous motor provided according to the present invention;

Fig. 3 is a control flowchart of the air conditioner provided according to the present invention.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a control block diagram of an air conditioner provided according to the present invention, Fig. 2a is a single-phase asynchronous motor provided according to the present invention, and Fig. 2b is a diagram of a phase detection circuit.

As shown in FIG. 1, the air conditioner provided according to the present invention includes a fan 10, an asynchronous motor 20, a phase detection part 30 and a control part 40 for controlling them.

The fan 10 rotates with the operation of an asynchronous motor 20 described below. For example, the fan 10 may be embodied as a compressor provided in an outdoor unit and compressing intake air to discharge to an exhaust port (not shown) or a blower fan provided in an indoor unit for heat exchange.

An asynchronous motor is powered by a common power source and rotates a rotor by a magnetic field flowing through a coil. An asynchronous motor as an example of the present invention is a single-phase asynchronous motor into which a single-phase current flows.

As shown in FIG. 2 a , the asynchronous motor 20 provided by the present invention takes a capacitive split-phase asynchronous motor in which a capacitor 24 is inserted in series on an auxiliary coil 23 to obtain starting torque as an example. That is, in the state where there is no capacitor 24, the supply current that was originally in a magnetic field balance state due to the current flowing through the main coil 22 is changed into a supply current whose phase is changed by the residual current flowing through the capacitor 24 inserted into the auxiliary coil 23 and flows in parallel. Through the coil, thereby destroying the balance state of the electromagnetic force to obtain the starting torque.

The rotor 21 is composed of squirrel cage windings, and the stator (not shown) is formed by parallel winding of the running winding as the main coil 22 and the starting winding as the auxiliary coil 23, so when connected to the parallel circuit In the case of single-phase AC voltage, due to the reactance difference between the main coil 22 and the auxiliary coil 23, a phase difference is generated in the currents flowing through the two circuits, thereby generating a rotating magnetic field and generating torque.

The centrifugal switch 26 is connected in series with the starting winding, and remains on at the initial stage of starting. When the speed of the rotor increases and reaches about 75% of the rated speed, the switch is cut off, and then the starting winding circuit is cut off, while the motor continues to rotate by the running winding . That is, at the time of starting, the capacitor 24 is required in order to break the balance state of the electromagnetic force (magnetic field) and obtain the starting torque. Then, when the rotor 21 starts to rotate and the rotation speed increases to a certain rotation speed, the rotor 21 operates in a state where the centrifugal switch 26 separates the capacitor 24 .

The phase detection unit 30 is used to detect the phases of the main coil 22 and the auxiliary coil 23 of the asynchronous motor 20 . At this time, the phase detection unit 30 may be represented as a phase detection circuit. The phase detection unit 30 may be configured to detect the phases of the main coil 22 and the auxiliary coil 23 by one phase detection unit, or may be configured as a first phase detection unit (not shown) provided corresponding to the main coil 22 and the auxiliary coil 23 respectively. out) and the structure of the second phase detection section (not shown).

Here, as shown in FIG. 2 b , the phase detection unit 30 may be represented as a phase detection circuit respectively provided in the main coil 22 and the auxiliary coil 23 .

At this time, the AC input power of the main coil 22 or the auxiliary coil 23 input through the input part 31 of the phase detection circuit is processed by the circuit and output with a constant waveform through the output part 32 . The control unit 40 judges the phase difference of the output waveform of the phase detection circuit, and according to the result, when the output phase difference between the main coil 22 and the auxiliary coil 23 is smaller than a predetermined value, it is determined that the fan motor is faulty and the operation of the fan 10 is stopped. Here, the control part provided according to the present invention may include a phase difference calculation part (not shown) that calculates the phase difference between the main coil 22 and the auxiliary coil 23 according to the detection result of the phase detection part, and an operation control part (not shown) that controls the operation of the fan 10 ( not shown).

During normal operation, the phase difference between the main coil 22 and the auxiliary coil 23 of the fan motor as a capacitive phase split asynchronous motor is 90 degrees.

The phase difference calculation unit calculates the phase difference. According to the phase difference calculation part of the air conditioner provided by the present invention, as an example, a zero-crossing circuit is used to calculate the position where the phase of the current passing through the main coil 22 and the phase of the current of the auxiliary coil 23 pass through the zero point. Phase difference.

When the phase difference calculated by the phase difference calculation unit is less than the reference value of 90 degrees or there is no phase difference, the operation control unit judges that the fan motor is in a stopped state or abnormal state, and stops the operation of the fan 10 .

In addition, the phase difference reference value for the control unit 40 to determine the abnormal state of the fan motor may include 90 degrees provided according to the exemplary embodiment of the present invention or a value within a range enabling it to operate normally.

Furthermore, the control unit 40 stops the fan 10 and notifies the user that the fan motor is in an abnormal state when the phase difference deviates from the reference value based on the calculation result of the phase calculation unit. At this time, the user can be notified of the abnormal state through methods such as alarm, OSD, and LED lighting.

In addition, if the control unit 40 detects an abnormal state of the fan motor, it can control the power supply unit 50 to stop supplying power to the system. For example, the control part 40 may control the power supply part 50 to stop supplying power to the system after a predetermined time elapses after detecting an abnormal state of the fan motor. Here, the system means all elements for cooling or heating included in the indoor and outdoor units, and the control part 40 may control the power supply part 50 to stop supplying power to at least one part included in the system.

Hereinafter, referring to FIG. 3 , the method for judging the fault of the fan motor of the air conditioner provided by the present invention will be described in detail.

First, the phase detection unit 30 detects the phases of the main coil 22 and the auxiliary coil 23 of the asynchronous motor 20, and the control unit 40 calculates the phase difference between the main coil and the auxiliary coil through a zero-cross point circuit (S1).

Since the asynchronous motor 20 provided by the exemplary embodiment of the present invention is a capacitive phase-separated motor, the reference value of the phase difference between the main coil 22 and the auxiliary coil 23 is 90 degrees as an example.

Next, the control unit 40 determines whether the phase difference between the main coil and the auxiliary coil is 90 degrees (S3), if the phase difference is less than 90 degrees or there is no phase difference, then it is judged that the fan motor is faulty and the operation of the fan 10 is stopped (S5).

Then, the control unit 40 stops the operation of the fan 10 , and stops the power supply to the system after a lapse of a predetermined time to stop the operation of the system.

As mentioned above, the direct detection method of fan motor failure based on the phase difference can distinguish and judge fan motor parts, single products, and unconnected wires, so it is also advantageous in service.

In addition, although the exemplary embodiment of the present invention uses 90 degrees as the reference value of the phase difference, the phase difference is not limited thereto, and it may be set as a value within an allowable error range for normal operation of the fan motor.

Also, although the present invention takes an air conditioner using a fan motor as its example, the present invention is not limited thereto and is also applicable to a system using an asynchronous motor.

While several embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various modifications may be made to the embodiments of the invention without departing from the principles and spirit of the invention. The scope of the invention is defined by the claims and their equivalents.

To sum up, according to the air conditioner and its control method provided by the present invention, by using the phase difference between the main coil and the auxiliary coil of the fan motor to directly detect whether a fault occurs, thereby preventing unnecessary power consumption and reducing The pressure applied to each power element of the air conditioner prevents the life of each power element from being shortened.

Claims (9)

1. An air conditioner, characterized in that it comprises: fan; An asynchronous motor that includes a rotor that rotates the fan, a main coil that rotates the rotor by flowing current from a single-phase power supply, an auxiliary coil that starts the rotor, and that generates A capacitor with a phase difference between them; a phase detection unit for detecting phases of the main coil and the auxiliary coil; A control unit configured to control the asynchronous motor to stop rotation of the fan when the phase difference between the main coil and the auxiliary coil detected by the phase detection unit is smaller than a reference value. 2. The air conditioner according to claim 1, wherein said reference value is 90 degrees. 3. The air conditioner according to claim 1, wherein the phase detection part includes a first phase detection part which detects the phase of the main coil and a second phase detection part which detects the phase of the auxiliary coil. 4. The air conditioner according to claim 1, wherein the control part further includes a zero-cross circuit. 5. The air conditioner according to any one of claims 1 to 4, characterized in that: Also includes a power supply that supplies power to the system; The control unit turns off the power supply unit when the phase difference between the main coil and the auxiliary coil is smaller than the reference value. 6. A control method of an air conditioner including a fan and a rotor having a rotor that rotates the fan, a main coil that rotates the rotor by flowing current from a single-phase power supply, and an auxiliary coil for starting the rotor and an asynchronous motor with a capacitor for generating a phase difference between said primary and auxiliary windings, said method comprising the steps of: comparing whether the phase difference between the main coil and the auxiliary coil is smaller than a reference value; When the phase difference is smaller than a reference value, the rotation of the fan is stopped. 7. The control method of the air conditioner according to claim 6, characterized in that the reference value is 90 degrees. 8. The control method of an air conditioner according to claim 7, characterized in that the step of comparing whether the phase difference is smaller than a reference value further comprises determining the position of the zero-crossing point of the current induced by the main coil and the auxiliary coil step. 9. The control method of an air conditioner according to claim 6, further comprising cutting off the power supply to the system when the phase difference is smaller than the reference value.

Images