JPS58205036A - Blower speed controller for airconditioner - Google Patents

Abstract

PURPOSE:To eliminate any unfavorable effect of heated reactor circuit while saving energy by a method wherein a blower is controlled by means of a reactor circuit and a stop circuit provided with hysteresis characteristic feeding-back the reactor circuit control side coil current to the comparison circuit reference voltage. CONSTITUTION:The output potential from an amplifier 6 is fluctuated due to the changes of resistance values of a room temperature thermistor 1. Resultantly, the set potentials of the maximum and minimum potential setting circuits 9, 10 are input into a comparison circuit 13. A reactor circuit 14 is saturated or unsaturated in accordance with the outputs operating a blower 15 within the range of the maximum and minimum values. Moreover, when air temperature decreases down to the set temperature of a stop circuit 17, a relay 18 is connected to stop the blower 15. Besides, the reactor 14 control side coil current is fed-back to the comparison circuit 13 through a constant current feedback circuit 19 to change the output potential from the comparison circuit 13 making the coil current value constant. In such a constitution, the blower 15 may be relieved from any unfavorable effect of heated reactor while saving energy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a blower speed control device for an air conditioner.

Generally, a control device for an air conditioner needs to vary the rotational speed of an AC motor for a blower, which is a load, and methods using thyristors or triacs have been widely known as methods for controlling this AC load. However, as shown in Figure 1, the load voltage waveform has large waveform distortion and also contains a large amount of high frequency components, which may cause vibrations of the motor, magnetic sound, electromagnetic sound, etc. Ta.

The conventional solution to this problem was to make the case of the electric motor out of casting, but in recent years, due to the cost reduction and weight reduction of electric motors, the cases mentioned above are often made out of sheet metal or plastic. A disadvantage has emerged in that it tends to generate the vibrations, magnetic sounds, and electromagnetic sounds mentioned above, which had been eliminated.

This invention was made to eliminate the above-mentioned drawbacks, and by using a new control means for controlling an AC load such as an AC motor, vibrations and magnetic noise can be reduced.

It is an object of the present invention to provide a blower speed control device for an air conditioner that can eliminate electromagnetic noise and save energy by controlling the rotation speed of the blower or stopping its operation based on the deviation between a predetermined environmental temperature and a set temperature. This is the purpose.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIGS. 2 and 3 are block diagrams and detailed circuit diagrams showing one embodiment of the present invention, and in FIG. 1, numeral 1 indicates a temperature sensor such as a thermistor for detecting room temperature.

2a, 2b, and 2c are three-pole, double-throw changeover switches that switch between cooling and heating; 3 is a DC power supply; 1) A stabilizing power supply is composed of a rectifier and smoothing circuit (not shown) that rectifies and smoothes the AC power supply current, a Zener diode, etc. This is what I got. 4 is a variable resistor, which allows the customer to arbitrarily vary the set temperature. 5 is a semi-fixed resistor, and when the resistance value of the thermistor l, that is, the room temperature reaches the set temperature for any set temperature of the variable resistor 4, the changeover switch 2 is switched to cold and warm respectively. Since the voltages applied to the blower are set in advance so that the potentials at the connection branch point between the thermistor 1 and the semi-fixed resistor 5 remain the same, the voltages applied to the blower become equal. 6 is an amplifier circuit whose output increases when the input potential decreases; conversely, when the input potential increases, the output decreases (becomes low).

7.8 is a diode, 9 is a minimum voltage setting circuit, and 10 is a maximum voltage setting circuit, which limits the anode side potential of the diode 7.8 to the minimum voltage and maximum voltage set respectively. . 11.12 is resistance.

Reference numeral 13 denotes a comparison circuit, the potential of one input point A of which is higher than the potential of the minimum voltage setting circuit 9, lower than the potential of the maximum voltage setting circuit 10, and the indoor temperature detected by the thermistor 1. A considerable potential is supplied. The reference voltage divided by the resistors 11 and 12 is supplied to the other input terminal of the comparator circuit 13, and this reference voltage is compared with the voltage at the point A, and an output potential corresponding to the potential at the point A is determined. Occur.

That is, if the potential at point A increases, the output also increases. 1
4 is a reactor circuit, which includes a first saturable reactor 14a and a second saturable reactor 14b, each having the same characteristics, and the control side winding is connected between the end of one winding and the other winding. The starting sides are connected in series, and the load side windings are connected by connecting the end of one winding and the end of the other winding, and the beginning of each winding is connected in series to the blower 15 and the AC power supply 16, which are loads. . Also, the number of windings on the control side is.

The number of windings is several times greater than that on the load side.

It is configured to obtain a large current change on the load side with a small current change on the control side. Note that the reactors 14a, 14
b are constructed so as to cancel out the generated voltages with each other by the above-described load side winding connection method so as not to generate high voltage on the control side.

Reference numeral 17 denotes a stop circuit which includes an IC (not shown) and a relay, and is configured so that when the input potential rises, the output potential of the IC rises and turns on the relay.

The normally closed contact 18 of this relay is connected to the reactor circuit 14° and the blower motor 15. It is connected in series to an AC power source 16. In addition, if the indoor temperature of the cooling/heating system drops by an arbitrary temperature below the set temperature, the relay of this stop circuit 17 is set in advance to be turned ON, and this relay is turned ON/OFF.
The operating temperature should have a hysteresis effect. A constant current feedback circuit 19 detects the current flowing through the control side windings of the reactors 14a and 14b and feeds it back to the other input terminal of the comparison circuit 13.

Based on the above configuration, the operation of an embodiment of the present invention will be explained with reference to the drawings.

Now, considering cooling, if the indoor temperature is very high compared to the set temperature, the resistance value of the thermistor 1 is small and the input potential of the amplifier circuit 6 is also low.As a result, the output potential of the amplifier circuit 6 is high. (The potential set by the highest potential setting circuit 10 is supplied to one input point A of the comparator circuit 13, and its output potential is given to the accelerator circuit 14. Therefore, since the reactors 14a and 14b approach the saturated state, The impedance on the load side decreases, the blower I5 rotates at the highest voltage, and the air conditioner is rapidly cooled.When the indoor temperature decreases, the potential detected by the thermistor 1 begins to rise, and the amplifier circuit 6 The potential supplied to the reactor circuit 14 via the comparator circuit 13 begins to decrease, and both the reactors 14a and 14b approach a non-saturated state (therefore, the number of revolutions of the blower 150 begins to decrease. When the temperature reaches the set temperature, the low voltage set by the minimum voltage setting circuit 9 is supplied to the reactor circuit 14 via the comparison circuit 13, so the rotation speed of the blower 15 is operated at the minimum rotation speed. When the indoor temperature drops by an arbitrary temperature set by the stop circuit 17, the relay installed inside the stop circuit 17 turns ON, and the normally closed contact 18 of this relay turns the blower off. 1
5 stops. Thereafter, when the indoor temperature rises again by the amount of hysteresis set by the stop circuit 17.

The blower 15 starts operating at the lowest voltage, and the same operation is repeated thereafter. In addition, in the case of heating, since the connection of the thermistor 1 that detects the indoor temperature is switched by the changeover switch 2, the minimum voltage, maximum voltage, and
Although the stop temperature, hysteresis temperature width, etc. are the same, the voltage change characteristics of the blower 15 with respect to the indoor temperature are completely opposite.

Also, when the indoor temperature reaches the set temperature, selector switch 2
Since the semi-fixed resistor 5 is set in advance so that the voltage applied to the blower 15 remains the same even when the voltage is switched, the voltage change characteristics of the blower 15 as shown in FIG. 4 are obtained. Further, since a saturable reactor is used, the voltage waveform applied to the blower 15 is as shown in FIG. 5. That is, due to the effect of the saturable reactor, when the blower voltage is large, the waveform becomes a sine wave that is almost similar to the power supply voltage waveform. Also, when the blower voltage is low, the waveform contains some waveform distortion, but this is low-frequency distortion and not the high-frequency waveform distortion that occurs when controlling with a conventional triac or thyristor. It can prevent motion, magnetic noise, and electromagnetic noise.

Also, during energizing operation, a large current flows through the load side windings of the reactors 14a and 14b due to the blower motor 15, and the reactor body generates heat and its impedance decreases. Even if the potential supplied to the input point A of the blower 1 is constant,
The set voltage of 5 may vary. In one embodiment of this invention.

By providing a constant current feedback circuit 19, if the current flowing through the control side windings of the reactors 14a, 14b increases, an increase in potential due to the increase in current is detected.

The comparison circuit 13 is fed back to the other input terminal of the comparison circuit 13.
to lower the output potential of the reactors 14a, 14b.
A constant current can always flow through the control side winding, and as a result, it is possible to prevent fluctuations in the set voltage of the blower 15 due to heat generation in the reactor even during long-time energized operation.

As explained above, according to the present invention, problems such as vibration, magnetic noise, electromagnetic noise, etc. of the blower can be solved, the rotation speed of the blower can be automatically varied or stopped depending on the predetermined environmental temperature, and wasteful energy can be avoided. Energy saving can be achieved without using .

Furthermore, this has the great practical effect of preventing fluctuations in the set voltage of the blower due to heat generated by the handle.

[Brief explanation of the drawing]

Fig. 1 is a voltage waveform diagram showing the blower voltage of a conventional air conditioner, Figs. 2 and 3 are a block diagram and detailed circuit diagram showing an embodiment of the present invention, and Fig. 4 is a diagram showing this FIG. 5 is a diagram corresponding to FIG. 1 showing an embodiment of the present invention. 1...Thermistor 6...Amplifier circuit 9...Minimum voltage setting circuit 10...
・Minimum voltage setting circuit 13... Comparison circuit 14... Reactor circuit 15... Blower l7... Stop circuit 19... Constant current feedback In the circuit diagram, the same reference numerals indicate the same or equivalent parts. Agent Shin Kuzuno - (1 other person) ・・・□、1:. spear 1 figure

Claims (1)

[Claims] (1) A blower, a switching means for switching between cooling and heating, a first temperature control means for varying an arbitrary set temperature of a predetermined environment, and a first temperature control means for varying an arbitrary set temperature of a predetermined environment. , temperature detecting means for detecting the predetermined environmental temperature; and when the temperature detecting means detects the predetermined environmental temperature reaching the preset temperature set by the temperature control means, the temperature does not change even if the switching means is switched. The second electrode is set so that the potential at the connection point with the detection means does not change and becomes equal potential.
temperature control means, an amplifier circuit that inputs the potential of the connection point, a maximum voltage setting circuit connected to the output of the amplifier circuit that sets the maximum voltage, a minimum voltage setting circuit that sets the minimum voltage, a comparison circuit that compares the output voltage of the amplifier circuit, which is consistent with the predetermined environmental temperature within a voltage range between the voltage and the minimum voltage, with a preset reference voltage, and outputs an output according to the deviation; An acdle circuit that inputs an output, and a stop circuit that operates with a predetermined hysteresis characteristic when the potential at the connection point rises. a constant current feedback circuit, wherein the constant current feedback circuit detects a current flowing through the control side winding of the reactor circuit and feeds it back as a reference voltage to the comparison circuit. Speed control device.