JP3127321B2 - Stepping motor control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for a stepping motor used in, for example, a part of an air conditioner.

[0002]

2. Description of the Related Art A stepping motor of this type has a rotor constituted by permanent magnets and a stator constituted by electromagnets. By changing the order in which the electromagnets are excited, the magnetic poles are moved, and the rotor moves with the movement of the magnetic poles.
That is, it rotates.

FIG. 6 shows a schematic configuration of a stepping motor 10, which comprises a cylindrical stator 11 and a rotor 12 made of a permanent magnet and supported inside the stator 11. The stator 11 includes upper and lower phases A and B, each having a 12-pole configuration, and the coils for the phases A and B are divided into two by a center tap. A plurality of stator teeth A are provided on the inner peripheral surface of the A phase of the stator 11.
A1, A1 ', A2, A2'... A12, A12 'are formed, and a plurality of stator teeth B13, B13'... B24 'are formed on the inner peripheral surface of the B phase. The terminal of each coil is connected to a power supply V via switches A and AB (B means Bar), B and BB. The rotor 12 is rotatably supported inside the stator 11 and is formed of a cylindrical permanent magnet. N poles and S poles are alternately magnetized in the circumferential direction.

FIG. 7 shows a state in which the coil is excited. For example, an N pole is generated in the stator tooth A1 and an S pole is generated in the stator tooth B13. Indicates a state in which is sucked.

Next, the operating principle of the stepping motor will be described with reference to FIG. The case of 1-2 phase excitation will be described. When switch A shown in FIG. 6 is turned on,
The N pole appears at the stator teeth A1, A2, A3,..., And the S pole appears at the stator teeth A1 ′, A2 ′, A3 ′,.
When the switch AB shown in FIG. 6 is turned on, S poles appear at the stator teeth A1, A2, A3,.
N poles appear at 1 ′, A2 ′, A3 ′. The same applies to the B phase.

First, when the switch A is turned on in step 1 shown in FIG. 8, N poles appear at the stator teeth A1, A2, A3... And S poles appear at the stator teeth A1 ', A2', A3 '.
A pole appears, and the north pole of the rotor 12 becomes the stator teeth A1 ', A
It is sucked by 2 ', A3' ... When the switches A and AB are turned on in step 2, the stator teeth A1, A2, A
3 ... B13, B14 ... N pole, stator teeth A
1 ', A2', A3 '... B13', B14 '...
S poles appear respectively. Therefore, the S pole of the rotor 12 is located between the stator teeth A1 and B13, A2 and B14..., And the S pole of the rotor 12 is located between the stator teeth A1 'and B
.. Are sucked in the middle of 13 ′, A2 ′ and B14 ′.

Next, as shown in step 3 of FIG. 8, when the switch B is turned on, the stator teeth B13, B14,.
, And S poles appear on the stator teeth B13 ', B14',..., And the S pole of the rotor 12 is the stator teeth B13,
In B14, the north pole of the rotor 12 is connected to the stator teeth B1.
3 ′, B14 ′... When the switches B and AB are turned on in step 4, the stator teeth B1
3, B14 ... A1 ', A2', A3 '... N
Poles, stator teeth B13 ', B14' ... A1, A2,
The S poles appear at A3..., And the S poles of the rotor 12 correspond to the stator teeth B13, B14.
3 ′, the north pole of the rotor 12 is the stator tooth B1.
3 ', B14'..., A1, A2, A3. In this way, the rotor 12 is rotated by sequentially exciting each coil according to the excitation pattern shown in FIG. 9 until step 8. The rotation angle per step of the stepping motor is 3.75 ° in 24-pole, 1-2-phase excitation. Step 1 to step 8 shown in FIG. 9 constitute one cycle. Further, as shown in FIG. 8, the distance between stator teeth having the same polarity is 30 °, and A
The phase between the phase and B phase stator teeth is 7.5 °.

FIG. 10 shows a non-excited state in which the stator teeth are not excited, and A-phase and B-phase stator teeth A1 and B1 are shown.
The magnet of the rotor 12 is stabilized where the area of 3 becomes maximum. The hatched portion indicates the N-pole or S-pole magnet portion of the rotor 12.

FIG. 11 shows a case of one-phase excitation, in which the magnet of the rotor 12 is stabilized at the excited B-phase stator teeth B13.

FIGS. 12 and 13 show the case of two-phase excitation. Also in this case, the magnets of the rotor 12 are stable at the illustrated positions. In the case of FIG. 12, the stator teeth A1,
This is the case where B13 is excited to the N pole and the stator teeth A1 'and B13' are excited to the S pole. In FIG. 13,
The stator teeth A1 are S pole, B13 is N pole, A1 'is N pole,
This is a case where B13 'is excited to the S pole.

FIG. 14 shows the coils 2 to 5 of the stepping motor, and FIG. 16 shows an excitation pattern when a voltage is applied to each of the terminals. Note that Co in FIG. 14 is a common terminal.

FIG. 15 shows the case of non-excitation, where the N-pole or S-pole of the rotor 12 is located at the center between a and b at the center position of each stator tooth from the relationship between the two phases A and B. To a stable state.

Next, as in the case of FIG. 8, when the coils 2 to 5 are sequentially excited in one or two phases as in the excitation patterns 1 to 8 shown in FIG. 16, the rotor 12 rotates by 3.75 °. Will be. In the excitation pattern 1, the magnet of the rotor 12 is attracted to the B-phase stator teeth by exciting only the coil 3. In the excitation pattern 2, by exciting the coils 4 and 3, the A-phase and B-phase stators alternately show N-poles and S-poles as shown, and the magnets of the rotor 12 are attracted to the illustrated positions. . It should be noted that the black triangles in the figure are drawn so that the movement of the magnet of the rotor 12, that is, the rotation of the magnet can be understood. When the excitation pattern is changed from 1 to 8 and the rotor 12 is rotated and stopped, as shown in FIG.
The rotor 12 stops at the positions of the stator teeth corresponding to the eight types of excitation patterns 6 and the magnets of the rotor 12.

Considering the excitation pattern shown in FIG. 16, the following can be understood. That is, the excitation pattern 4
In the cases of (8) and (8), the area where the A-phase and B-phase stator teeth of the stator facing the magnet (S-pole) of the rotor 12 on the left side of the black triangle mark are the largest compared to the other excitation patterns. Has become. This corresponds to the case of FIG. 12 described above. In the case of the excitation patterns 2 and 6 in FIG. 16, the facing area between the magnet of the rotor 12 and the A-phase and B-phase stator teeth is smaller than in the case of the excitation patterns 4 and 8. This corresponds to the case of FIG. 13 described above. In the case of FIG. 9, steps 2 and 6 are stable points.

[0015]

That is, when the stepping motor is stopped, the pattern shown in FIG.
6 (corresponding to the excitation patterns 4 and 8) is the same as the non-excitation stable state shown in FIG. Therefore, when the excitation of the coil is turned off, the rotor 12 moves to a non-excitation stable state in other patterns. In other words, it becomes a cause of slip.

When the stepping motor is stopped in this way, if the excitation is terminated by ending with an arbitrary excitation pattern, the magnet of the rotor 12 is stopped between the A-phase and B-phase stator teeth with a probability of 3/4. In this case, the non-excitation holding torque (detent torque) extremely decreases, falls below the nominal stationary holding torque, and causes slippage. For example, when the stepping motor is used for controlling the flap of the air outlet of the air conditioner, the stop position of the stepping motor is controlled in consideration of only the angle of the flap. Since there is a stop at which the holding torque becomes small, there arises a problem that the structure must be designed in accordance with the small torque.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to determine not only the flap angle but also the stepper motor stop position.
By setting the non-excitation holding torque to the maximum position in consideration of the rotor position of the
Allow slippage to prevent slippage immediately after stopping
At the same time, design the structure according to the small non-excitation holding torque.
Flap control for air conditioners
It is an object of the present invention to provide a control circuit for a stepping motor capable of reducing the size of the stepping motor for use in the stepping motor . ─
That's it

[0018]

Therefore, a control circuit for a stepping motor according to the first aspect of the present invention has an N pole,
A plurality of stator teeth A1, A that alternately generate S poles
1 ', A2, A2'... B13, B13 '... In the circumferential direction, and the stator teeth A1, A
1 ', A2, A2' ··· B13, B13 'N pole alternately facing circumferentially ..., and a rotor 12 comprising a permanent magnet S poles are magnetized stepping motor 1
0 , the stator teeth A1, A1 ', A2, A
In the control circuit of the stepping motor to which the 2 ', ... B13, B13' to generate a predetermined magnetic poles ... rotate the rotor 12, the stepping motor 1
0 is used to control the flap 50 of the air outlet of the air conditioner.
Control means 20 for stopping the stepping motor 10 at a position where the non-excitation holding torque is maximized.
The control means 20 has a magnetic pole of the rotor 12 and a pole having a different polarity.
At the position where the area facing the data teeth A1 and B13 is maximized
It is characterized in that it is stopped .

[0019]

[0020]

[0021]

The control circuit for a stepping motor according to claim 1 is provided.
Then, make sure that the stepping motor 10
Stop at the position where is the maximum. Therefore, the flap 50
When stopping at a specific angle
The stop position coincides with the position where the non-excitation holding torque is maximum.
Stop at that position,
Is also stopped at the position where the non-excitation holding torque is maximized.
As a result, the flap 50 should be stopped at an angle
It will stop at an angle slightly deviated from
In the position, the non-excitation holding torque of the stepping motor 10 is
Since it is the maximum, occurrence of slippage immediately after stopping can be prevented.
In addition, the structural design of the stepping motor 10
Is advantageous, and downsizing can be achieved. In addition,
The deviation of the angle of the pump 50 has almost no effect on the actual wind direction control.
There is no echo and no inconvenience occurs for the user .

[0022]

[0023]

[0024]

Next, a specific embodiment of a control circuit for a stepping motor according to the present invention will be described in detail with reference to the drawings. Note that the configuration and the excitation pattern of the stepping motor are the same as those in the related art, and the gist will be described in detail. FIG. 1 is a block diagram of a control circuit for controlling the rotation of the stepping motor 10. The stepping motor 10 is driven by a control unit (control means) 20 composed of a microcomputer and a signal from the control unit 20 according to an excitation pattern. It comprises a drive circuit 30 and a DC power supply section 40 for supplying power to each section.

FIG. 2 is a block circuit diagram of the drive circuit 30. A signal from the control unit 20 is applied to each coil of the stepping motor 10 via a photocoupler 31 and a driver 32. Here the photocoupler 31
Is used to electrically insulate the control unit 20 side and the stepping motor 10 side by optical coupling, and to improve noise immunity generated by the coil of the stepping motor 10. The driver 32 outputs a pulse signal from the control unit 20 to obtain power required to drive the stepping motor 10.

Here, a pulse signal corresponding to the excitation pattern as shown in FIG.
The signal is amplified by the driver 32 via the photocoupler 31 and the rotation of the stepping motor 10 is controlled by applying the coil of the stepping motor 10.

Next, the control of the present invention will be described. When the stepping motor 10 is stopped, the application of the voltage is stopped by exciting the excitation patterns 4 and 8 shown in FIG. 16, that is, the coils for applying the voltage with the coils 4 and 5 or the coils 2 and 3 being excited. The stepping motor 10 is stopped. The control in the case of the stop is performed by the control unit 20 which receives the signal of the stop switch (off switch), and is performed by, for example, software. Therefore, when the stepping motor 10 is stopped, in the case of FIG. 16, the operation is always terminated by the excitation patterns 4 and 8. In the non-excitation state, the magnet (S pole) of the rotor 12 and the stator 11, the opposing area between the A-phase and B-phase stator teeth A1 and B13 is maximized, the non-excitation holding torque is maximized, and no slippage occurs immediately after the motor stops, unlike the related art. At the start of driving of the stepping motor, the driving is started from the stop excitation pattern.

FIG. 3 shows that the stepping motor 10 controls the rotation of the flap 50 at the air outlet of the air conditioner (vertical direction).
15 is a connector connected to the power supply unit and the control unit 20, and 16 is a rotary shaft connected to the connection port of the flap 50. Stepping motor 10
As shown in FIG. 3, especially when the flap 50 and the like are connected, there is a downward force due to the weight of the flap 50 (arrow in the figure), and when the non-excitation holding torque is small, slip occurs. Although it is easy, the configuration according to the present invention prevents slippage from occurring when the motor is stopped even when the motor is stopped even when the motor is connected to the flap 50. Therefore, the non-excitation holding torque can be increased by stopping the motor stop position in consideration of not only the angle of the flap but also the rotor position of the motor.

The stepping motor can be applied not only to a flap of an air conditioner but also to an electric expansion valve. In other words, by rotating the rotor,
The present invention can also be applied to a configuration in which a linear motion is converted into a linear motion with a screw-like configuration, a needle is connected to the rotor, the valve opening is controlled by the linear motion of the needle, and the refrigerant is controlled.

FIG. 4 shows a connection portion of the coils 2 to 5 in the case of two-phase excitation. Each of the coils 2 to 5 is connected to each terminal of the connector 15. FIG. 5 shows an excitation pattern in the case of two-phase excitation. In the case of excitation patterns 0 and 4, the non-excitation holding torque is maximized, so that the motor is stopped in such an excitation pattern.

[0031]

As described above, according to the control circuit for a stepping motor according to the first aspect, the stopping position of the stepping motor is controlled.
Not only the flap angle but also the stepper motor
The position where the non-excitation holding torque is maximized considering the rotor position
The flap angle slightly
Although slipping, slippage immediately after stopping can be prevented.
As a result, if the flap that I thought stopped stopped suddenly moves
Can prevent users from feeling uncomfortable
Wear. In addition, the structure is set to match the small non-excitation holding torque.
The inconvenience of having to measure
The downsizing of the motor can be achieved .

[0032]

[0033]

[Brief description of the drawings]

FIG. 1 is an overall block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a drive circuit according to the present invention.

FIG. 3 is an exploded perspective view when the stepping motor of the present invention is used for controlling a flap.

FIG. 4 is a circuit diagram when the stepping motor of the present invention is excited in two phases.

FIG. 5 is a diagram showing an excitation pattern when two-phase excitation is performed in the case of FIG. 4 of the present invention.

FIG. 6 is a configuration diagram of a stepping motor.

FIG. 7 is an explanatory diagram showing a rotation operation of a stepping motor.

FIG. 8 is an explanatory diagram showing excitation of a stepping motor.

FIG. 9 is an explanatory diagram showing an excitation pattern of a stepping motor.

FIG. 10 is an explanatory diagram showing a non-excitation state.

FIG. 11 is an explanatory diagram showing a case of one-phase excitation.

FIG. 12 is an explanatory diagram showing a case of two-phase excitation.

FIG. 13 is an explanatory diagram showing a case of another state of two-phase excitation.

FIG. 14 is a diagram illustrating connection of a coil portion of a stepping motor.

FIG. 15 is an explanatory diagram showing a non-excitation state.

FIG. 16 is a diagram showing excitation patterns and positions of magnets.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stepping motor 11 Stator 12 Rotor 20 Control part (control means) A1 Stator tooth A1 'Stator tooth B13 Stator tooth B13' Stator tooth

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-143298 (JP, A) JP-A-60-2065 (JP, A) JP-A-63-143441 (JP, A) JP-A-1- 184359 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 8/00 H02K 37/00 F24F 11/00

Claims (1)

(57) [Claims] 1. A plurality of stator teeth (A1, A1 ′, A2, A2) that alternately generate north and south poles according to the direction of current.
2 '... B13, B13'...) In the circumferential direction and the stator teeth (A1, A1 ',
A2, A2 '... B13, B13'...) And a rotor (12) composed of permanent magnets facing each other in the circumferential direction and having N and S poles magnetized alternately.
(10) wherein the stator teeth (A1, A1 ', A
In 2, A2 '··· B13, B13 ' ···) to thereby generate a predetermined magnetic pole control circuit of the stepping motor so as to rotate the rotor (12), the Suteppi
Motor (10) to the flap of the blower of the air conditioner
With used for control of (50), comprising a control means for non-excited holding torque the stop position of the stepping motor (10) stops at a position where the maximum (20), the control means (2
0) is a stator tooth (A) of a different polarity from the magnetic pole of the rotor (12).
1, B13) and stop at the position where the area facing
The control circuit of the stepping motor, characterized in that the so that.