JPS626440B2 - - Google Patents

Description

[Detailed Description of the Invention] Although there are no known examples of using a stepping motor to control the air blowing angle of an air conditioner, generally when controlling the rotational position of a stepping motor or a servo motor, The reference position is detected using a micro switch that closes when the motor shaft (or an object controlled by the motor, such as a damper) comes to a certain predetermined reference position.
However, according to this method, when the air conditioner is frequently returned to the reference position, for example, when the air blowing angle of a domestic air conditioner is constantly swung up and down, as will be described later as an embodiment of the present invention. passes through the reference position hundreds of thousands of times, which causes problems with durability in microswitches and the like. Also, when using a non-contact photoelectric switch, dust etc. (there is a lot of dust in the air,
special care must be taken to prevent it from sticking (it tends to get sticky). Moreover, providing a switch itself deteriorates reliability.

The present invention relates to a reference position detection method and a rotation angle control method for controlling the rotation angle of a stepping motor, and is particularly suitable for detecting a reference position for motors that frequently detect positions or for motors that frequently pass through a reference position. This makes it possible to control a predetermined angle from a reference position without using a dedicated switch, and eliminates all the drawbacks mentioned in the prior art.

Another object of the present invention is to provide an excellent method for swinging the wind blowing direction of a domestic air conditioner within a predetermined angle range based on a certain position, or for keeping it stationary at a certain predetermined position.

An embodiment of the present invention in which the present invention is used to control the blowout angle of air from a domestic air conditioner will be described below with reference to the drawings.

FIG. 1 is a sectional view of the main parts of an indoor unit of a separate type air conditioner.

1 is an outer frame, 2 is a heat exchanger, and 3 is a blower fan. 4 is a damper provided at the air outlet 5,
It rotates up and down around the shaft 6.

Indoor air is transferred to a heat exchanger 2 by a blower fan 3.
During cooling, the air is sucked in as shown by the arrow 7, and when cooling, it is cooled and exits from the air outlet 5. The upper and lower walls 8, 9 forming the air outlet 5 are hydrodynamically designed to accommodate the bending angle of the damper 4. It is bent more than a degree and blows out as shown by arrow 10. Therefore, by rotating the damper 4 up and down about the shaft 6, the direction of the blown air 10 also changes from horizontal to downward. Now, the present invention is based on this damper 4.
This relates to the method of driving the motor, but in order to clarify its contents, Fig. 1 will be briefly explained. The wind blowing angle is designed such that the maximum upward blowing angle is in the horizontal direction as indicated by arrow 10', and the blowing angle does not blow upwards, but swings between this direction and downwards. Therefore, conventionally, a switch would be installed at the rotational angle position of the damper that provides the blowing angle of 10', and it would be known by opening and closing the switch that the damper has reached this position. , only a stopper 11 is provided near this horizontal position. Therefore, the damper 4 can no longer be moved by the stopper 11.
It is designed not to rotate upward.

If the switch is installed in this position, if you move the damper up and down to swing the blowing air downward from the horizontal and from below to the horizontal, the switch will open and close each time it reaches the horizontal position, for example. , if the swing period is 15 seconds, in 1 hour
3600/15 = 240 times, 1440 if used 6 hours a day
140,000 times in 100 days. Therefore,
Ordinary switches have problems with their durability and are not practical. This is where the advantage of the drive system of the present invention that does not use a switch arises.

Although the shaft of the damper 4 is not shown, it is coupled to a stepping motor (or pulse motor). The damper 4 is rotated up and down by the left and right rotation of the stepping motor.

A stepping motor is generally known as a control motor for digital equipment, and its configuration is schematically shown in FIG. 2.

The stator 12 includes coils 16a and 1, respectively.
Four salient pole elements 1 wound with 6b, 16c, and 16d
3a, 13b, 13c, 13d, and sub salient pole elements 17a, 17b, 17c, 1 with no coil wound thereon.
7d is provided. Further, the rotor 14 is made of a permanent magnet magnetized to N--S as shown in the figure, and its shaft 15 usually comes out from the motor via a speed reduction mechanism such as a gear. This shaft is connected to the shaft 6 of the damper 4 shown in FIG. 1 mentioned above.

Now, in FIG. 2, when the coil 16a is excited with the polarity shown, the _N1 pole of the rotor is attracted to the rotor 13a and comes to rest in the state shown in FIG. This phase of the coil 16a is called a phase. Next, when the excitation of this phase is stopped and a current is applied to the phase, that is, 16b, _N2 of the rotor is attracted to this pole 13b, and the rotor rotates 22.5 degrees to the left as shown by the arrow in the 1-step angle diagram. Stop again. From then on, phase 1
When phase 6c and phase 16d are sequentially switched and energized, the rotor is attracted by this and continues to rotate one step angle at a time. Now, the magnets are excited in the order of phase-phase-phase-phase-phase, but if this order is reversed, the rotor will rotate in the opposite direction. The above explanation is a method called one-phase excitation because only one phase is always excited.

In the time chart shown in Figure 3, the one to the left of time 33 is a method called two-phase excitation, in which two phases are always excited at the same time, which causes less rotor vibration than the one-phase excitation described above. It is known as a method, but between 28 and 29, the phase and phase are 2.
Between 9 and 30, the phases are excited, and the two phases are excited in sequence, and the excited phase is shifted every clock (cycle _t0 seconds) and rotates by one step angle. One step angle of the rotor is 22.5 degrees in the case of FIG. 2, but as mentioned above, the shaft is decelerated by gears, etc., so in reality, the damper 4 in FIG. It's about ゜. Therefore, by counting the number of clock pulses from a certain reference position, the angle of the damper can be determined.

Furthermore, a characteristic of step motors is that in the case of a normal induction motor, a very large excitation current flows when the rotor is fixed by an external force, whereas in the case of a step motor, the excitation current is The point is that it is almost the same as the steady state case. Fig. 4 shows an example of the excitation current in the case of two-phase excitation.The rotor vibrates during the period _t0 , so there is some pulsation, but after that it settles down to a constant value (steady value).

The present invention can be realized using the features of the step motor as described above.

FIG. 5 shows one embodiment of a circuit for driving a step motor, in which the microcomputer 26
is used to connect the winding 16a of the step motor from the output port E~ _E3 through the driver 25.
~16d is excited. Microcomputer 26
In addition, inputs such as operation switches are connected to the A port, and outputs for controlling the blower, compressor, etc. are connected to the port, and the power supply circuit 18 connects the power to V and turns on the power A reset circuit including a resistor 23 and a capacitor 24, which resets the microcomputer to its initial state when the microcomputer is reset, is connected to the reset terminal R.

The control of the step motor according to the present invention described below is all executed by a program stored in the microcomputer 26.

Now, in order to rotate the damper in Fig. 1 to the desired angle, a reference position is required, and once you know that the damper is at that position, you can rotate the step angle by a predetermined number from that position. That's fine. Therefore, the microcomputer requires a counter for the current position relative to the reference position (a counter for counting the step angle of movement). The current position of the damper can be recognized by the counter based on the reference position. For example, when moving downward, add 1 to the counter every clock, and when moving upward, subtract from the counter, so that the current angle of the damper can always be recognized. However, when a microcomputer's power is turned off, its internal memory usually disappears. Furthermore, even if the power is not turned off, the initial position of the damper cannot be known. Therefore, in such a case, it is necessary to set the damper at the reference position, and the present invention can be used for this purpose.

That is, in the present invention, when setting the damper at the reference position, the damper is driven toward the stopper 11 with a sufficient number of pulses to ensure that the damper always reaches and hits the stopper 11 shown in FIG. The microcomputer is moved in the opposite direction by the number of pulses (step angle), and that position is used as a reference position, and the counter inside the microcomputer is set to 0 (value of the reference position).

These operations will be explained with reference to FIGS. 3 and 6. First, in order for the damper to always reach the stopper 11, the movable range of the damper, for example
360°, and if the damper moves 0.6° by excitation per 1 clock pulse of the step motor (1 step angle of damper 1 = h), then 360 ÷
It is necessary to move the damper toward the stopper for 0.6 = 600 pulses. Figure 3 shows operation with two-phase excitation, and since both phases are excited at time 26, the damper (rotor) is at a stable point between the phases, that is, as shown in Figure 6. It is at point 26'.
Next, since the excitation becomes both phase and phase, the damper (rotor) moves to a stable point 27' in the middle (moves by step angle h) in this way, and at time 30, the damper (rotor) Stopper position 42
It has reached the stable point 30' of the phase just before (Fig. 6). Then, at point 31, the stable point moves to 31'', but since the damper collides with the stopper, it actually stops at point 31'.Therefore, the rotor of the step motor is also fixed by the stopper, but
As mentioned earlier in the description of the step motor, the excitation current of the step motor does not increase even if the rotor is fixed by an external force. Therefore, there is no fear of burning out the motor. Here, the damper has already reached the stopper position (reference position), but the microcomputer continues to send the predetermined pulse as described above, and at the next point 32, the stable point is the midpoint between the phases. Become. In FIG. 6, this point is 32'' on the right side of the stopper position 42.
It occurs at 32' on the left, but it is blocked by the stopper and cannot go to the right, so it returns to the stable point on the left (it is also possible that it does not return from 31' while still hitting the stopper).The next stable point is Since it is between the phases, it moves to 33'. In this way, after colliding with the stopper, before the stopper, 2 step angle + stable point and stopper distance (δ),
It vibrates in the range of (2h+δ), but when the microcomputer finishes excitation for the predetermined number of times, it becomes one-phase excitation (phase) and stops after time 34. At this time, in Figure 6, the phase tries to stop at the stable point 34'', but
It hits the stopper and stops at 37'.

The time of this one-phase excitation is longer than the conventional clock pulse time _t0 , and the excitation is performed for _t1 , so that vibration of the rotor (damper) is eliminated.
At this point, the damper has reached the reference position (stopper position). At this time, the distance from the stopper is 0 in this example, but even if it deviates farthest, it will take 2 steps + the distance from the stable point to the stopper as described above, and the maximum distance is 3 hours (3 hours).
Step angle). Since h=0.6° in this example, this is within 1.8° at most.

It is possible to set the counter in the microcomputer to 0 and use it as the reference position, but in this case, there is a possibility that it will collide with the stopper 4 every time it is moved to the reference position.In order to prevent this, in this example, From time 37 onwards, it is returned by one step angle and one phase excitation in the opposite direction. Therefore, the sixth
At the point shown in FIG. 38' (the stable phase point), it is completely stopped and the reference position is reached, and at this point the counter in the microcomputer is set to 0 and the reference position is set. By doing this, the microcomputer can move the damper to any desired angle from now on, and even if the damper is moved to the reference position, it will not collide with the stopper. Also,
Since one-phase excitation is performed at the final stop, the excitation power is less than two-phase excitation, and the shaft position does not move even if excitation is interrupted.

As explained above, when setting to the reference position for the first time, it can be set reliably without using a switch, and even if you move it to the reference position many times, it will collide with the stopper. There's nothing to do.

In the above example, a permanent magnet type 4-phase step motor was explained as the step motor.
The present invention is not limited to this, and other types of step motors or pulse motors can be used. However, it is unsuitable for the excitation current to become too large when the motor is in the locked state.

As described above, in the present invention, when initially setting the step motor to a rotational position, the step motor is rotated by a predetermined angle sufficient to rotate the step motor toward the stopper in a fixed direction by multi-phase excitation and collide with the stopper. After this rotation, one-phase excitation is applied for a predetermined period of time in a direction that provides rotation in the same direction, and then one-phase excitation is applied for a predetermined period of time that provides rotation in the opposite direction to the aforementioned rotation direction, so that the reference position is set. , has the following effect.

(1) No switch is required, so the lifespan is long.

(2) The configuration is simple, just by providing a stopper.

(3) It only collides with the stopper the first time, and there are no subsequent collisions, so the lifespan is long.

(4) Since the step motor's excitation current does not flow excessively even in the locked state, a special excitation circuit is not required.

(5) As a result of being able to use one-phase excitation when stopped, it is possible to save energy by de-energizing after stopping, and there is no inconvenience that the reference position shifts when restarting.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of an indoor unit of an air conditioner using the control method of the present invention, FIG. 2 is a block diagram of a step motor controlled by the control method of the present invention, and FIG. is an excitation time chart of a step motor in an embodiment of the present invention, FIG. 4 is an excitation current waveform diagram of a step motor controlled by the control method of the present invention, and FIG. 5 is a diagram of the excitation current waveform of the step motor controlled by the control method of the present invention. FIG. 6 is a block diagram of one embodiment of the control section, and is a time chart showing the movement of the shaft position of the step motor according to the control method of the present invention. 4...damper, 11...stopper, 6...shaft.

Claims (1)

[Claims] 1. A step motor consisting of a rotor made of a permanent magnet and a stator made of a plurality of excitation phases, a stopper that prevents the rotation shaft of this step motor from rotating in one direction at a certain position, and a rotation angle of the step motor. The rotation angle of the step motor is controlled based on a certain reference position, and when the rotation axis of the step motor is initially set to the reference position, the rotation angle of the step motor is controlled by the stopper. The step motor is rotated in a certain direction by multi-phase excitation to a predetermined angle sufficient to collide with the stopper, and after this rotation, one-phase excitation is applied for a predetermined period of time in a direction that provides rotation in the same direction. A method for controlling a step motor, in which one-phase excitation is then performed for a predetermined period of time to provide rotation in the opposite direction to the aforementioned rotation direction, and the step motor is brought to a reference position.