JPH0823777B2 - Air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to protection of a main control circuit against a power supply abnormality and an air conditioner considering an abnormality alarm.

[Technical background of the invention and its problems]

FIG. 3 shows a system diagram for controlling an indoor fan motor of a conventional air conditioner.

In recent years, motor control by a microcomputer is common, and a noise filter 5, a positive temperature coefficient thermistor 6, a transformer 7 and a rectifier 8 are connected to the microcomputer 10 with the power supply terminal 1, the switch 2, the fuse 3 and the surge absorber 4 as a common part. The power supply voltage is supplied via the constant voltage circuit 9. Further, drive power is supplied to the fan driving transistor motor 17 through the rectifier 14, the switching power supply 15, and the motor drive circuit 16. Here, the control output of the microcomputer 10 is given to the display circuit 12 for performing various displays, and is also given to the motor drive IC 13 constituting a DA converter or the like. The output of the motor drive IC 13 is sent to the switching power supply 15 and the motor drive circuit 16 to control the duty ratio and the like of the signal for driving the motor 17.

In such an air conditioner, the outlet of the power supply terminal 1 is generally a T-type shared by 100V and 200V, so that a device for 100V is connected to a 200V power socket, etc. There is a possibility that an accident may occur in which the voltage is applied.

Conventionally, in consideration of this kind of accident, when applying a voltage higher than the rated voltage, the fuse 3 and the surge absorber 4 are destroyed to protect the circuit.

However, with such a method, it is not possible to respond to the immediate restart of operation because the parts are destroyed.

In addition, it is not possible to notify the operator or user of the fact that an abnormal voltage is applied simply by raising the pressure against parts such as fuses, and further destroying each element of the main circuit, such as a microcomputer. There was a fear.

[Object of the Invention]

The present invention has been made based on the above circumstances, and an object thereof is to provide an air conditioner capable of detecting and coping with an abnormal voltage and issuing an alarm without depending on the destruction of parts.

[Outline of Invention]

To achieve this object, according to the present invention, a voltage abnormality on the power supply circuit side of the microcomputer is detected to shut off the motor drive power supply circuit, and an alarm is issued via the microcomputer.

Example of Invention

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a system diagram showing an embodiment of the present invention.
The same reference numerals as those in the conventional device in the figure denote the same elements.

According to the figure, a detection circuit 110 for detecting an abnormal voltage is provided on the power supply side of the microcomputer 10, and a detection circuit 120 for detecting an abnormal voltage is also provided on the motor control power supply side. An alarm circuit 130 is connected to the microcomputer 10.

Below, focusing on the parts that differ in configuration from the conventional device,
The operation of this embodiment will be described.

First, it is assumed that the power supply terminal 1 to be connected to the 100V AC power supply is mistakenly connected to the 200V AC power supply. Immediately after that, since the resistance value of the positive temperature coefficient thermistor 6 is low, the output voltage of the transformer 7 and the output voltage of the rectifier 8 are approximately twice the rated voltage. The constant voltage circuit 9 continues to output the same voltage as that in the normal connection even with respect to such an abnormal voltage. Therefore, the microcomputer operates normally.

Here, when the user sets the air flow rate using the operation unit 11, the microcomputer 10 outputs the signals “L” and “L” from the ports b and c in response to the stop and the signal “L” in response to the weak. "," H ", corresponding to the signal" H "," L "
, And outputs signals “H” and “H” corresponding to strong. Therefore, except when set to stop, the motor drive IC 13 drives the switching power supply 15, so that a DC voltage that is twice as high as the normal time output from the rectifier 14 is applied to the switching power supply 15 and destruction of its constituent elements occurs. I'm worried.

At this time, in the first abnormal voltage detection circuit 110,
The output voltage of the rectifier 8 is monitored, and when the voltage becomes higher than normal, the transistor Q ₁ is turned on via the Zener diode Z ₁ . Therefore, the transistor Q _{2 is} also turned on, and the control ports b and c of the microcomputer 10 are
To the ground potential, that is, "L", "L".

Therefore, it is possible to avoid the situation where the gate of the switching power supply 15 is cut off via the motor drive IC 13 and the constituent elements of the switching power supply 15 are destroyed by the high voltage.

Next, when the resistance value of the positive temperature coefficient thermistor 6 increases and the voltage on the secondary side of the transformer 7 decreases with the passage of time, and falls below the rated voltage, the first abnormal voltage detection circuit 110 detects an abnormal voltage. No, so transistor Q ₂ is turned off. In this state, when the user uses the operation unit 11 to set the air flow rate, the above-mentioned signals are output from the control ports b and c of the microcomputer 10, and at this time also, the components of the switching power supply 15 There is concern about destruction.

The second abnormal voltage detection device 120 copes with this, and when the power supply terminal 1 is erroneously connected, it detects a high voltage and causes the microcomputer 10 to activate the alarm circuit 130 to prevent the operation of the operation unit 1. It is a thing.

That is, in the second detection circuit 120, the output voltage of the rectifier 14 of the motor control power supply, which is directly applied with a high voltage without passing through the power supply transformer 7, is drawn from the microcomputer power supply side and calculated with the reference voltage formed by the Zener diode Z _2. The comparison is made by the amplifier OP. When an abnormal voltage occurs, an output is generated in the operational amplifier OP, and this is supplied to the port a of the microcomputer 10.

Microcomputer 10 based on input to port a
The alarm circuit 130 can be operated to generate an alarm sound by a buzzer or to display an alarm display such that all the pilot lamps of the display circuit 12 blink. Display circuit 12, for example, in the air conditioner capacity variable type is 90H _Z indicating the operating state of the compressor motor as shown in FIG. 2, 75H _Z, 65H _Z, 55H
_Z, there are pilot lamps 20, such as 45H _Z, also there is such as a pilot lamp 21 which indicates the defrost. All of these pilot lamps 20 can be flashed based on the output of the operational amplifier OP. When all or part of the operation unit 11 is a wireless controller, a buzzer can be incorporated in the controller or an existing lamp can be used to similarly issue an alarm.

Because of the above situation, if the power outlet of the equipment is reconnected to the rated power source, the alarm disappears and the operation can be started immediately. However, it goes without saying that the elements such as the fuse 3, the surge absorber 4, and the positive temperature coefficient thermistor 6 have the capacity to withstand the abnormal voltage in the above description.

Needless to say, the warning may be given by other means such as voice.

〔The invention's effect〕

According to this invention, with the above configuration,
An air conditioner having the following effects can be provided.

When the abnormal voltage is applied to the power supply, the switching power supply on the motor control power supply side can be shut off immediately, so that the switching power supply element can be prevented from being damaged.

In the configuration in which the parts are destroyed, the restart operation cannot be performed unless these parts are replaced, but in the present invention, the operation can be immediately restarted only by changing the connection.

Since an alarm is issued when an abnormal voltage is generated, the safety of the equipment can be confirmed, and the operator can be warned about restarting operation.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an essential part of the embodiment, and FIG. 3 is a system diagram of a conventional device. 1 ... Power supply terminal, 2 ... Switch, 3 ... Fuse, 4
…… Surge absorber, 5 …… Noise filter, 6 ……
Positive characteristic thermistor, 7 ... Transformer, 10 ... Microcomputer, 13 ... Motor drive IC, 14 ... Rectifier, 15 ... Switching power supply, 16 ... Motor drive circuit, 17 ... Fan drive transistor motor, 110 ……
First abnormal voltage detection circuit, 120 ... Second abnormal voltage detection circuit, 130 ... Alarm circuit.

Claims (2)

[Claims] 1. A microcomputer is operated by a secondary side voltage of a transformer having a positive temperature coefficient thermistor on a primary side, and electric power supplied from an electric power source common to the transformer to an indoor fan motor via a switching power source,
In an air conditioner controlled by changing the operating state of the switching power supply according to the output signal of the microcomputer, it is detected that the secondary side voltage of the transformer is higher than a normal voltage, and the power supplied to the indoor fan motor is detected. An air conditioner comprising an abnormal voltage detection circuit for converting an output signal of the microcomputer so as to cut off. 2. A microcomputer is operated by the secondary side voltage of a transformer having a positive temperature coefficient thermistor on the primary side, and electric power supplied from an electric power source common to the transformer to an indoor fan motor via a switching power source is supplied.
In an air conditioner controlled by changing the operating state of the switching power supply according to the output signal of the microcomputer, it is detected that the secondary side voltage of the transformer is higher than a normal voltage, and the power supplied to the indoor fan motor is detected. A first abnormal voltage detection circuit that converts the output signal of the microcomputer so as to cut off, an alarm circuit that operates by the output of the microcomputer, and an input side voltage of the switching power supply that is higher than a normal voltage. A second abnormal voltage detection circuit for detecting and applying a command to activate the alarm circuit to the microcomputer.