JPH0583992A - Driver for four-phase step motor - Google Patents

Abstract

PURPOSE:To rotate a four-phase step motor with only one current supply. CONSTITUTION:First terminals 111-141 of exciting coils 11-14 having second terminals 112-142 connected with each other are connected, through first to eighth semiconductor switching elements Q1-Q8 arranged correspondingly, with the plus and minus terminals 161, 162 of a driving current supply 16. A rotation control section 15 controls ON/OFF operation of the first to eighth semiconductor switching elements Q1-Q8 thus rotating a synthesized magnetic field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a four-phase stepping motor that makes one round of an electrical angle in 16 steps.

[0002]

2. Description of the Related Art As shown in FIG. 6, a conventional four-phase stepping motor has an A-phase coil 91 and an anti-A-phase coil 9 that generate magnetic fields in directions different from each other by 180 degrees.
2 and four sets of exciting coils 91 to 94, which are a B-phase coil 93 and an anti-B-phase coil 94, which generate magnetic fields in directions 180 degrees different from each other in a direction orthogonal to the exciting coils 91 and 92. In addition, one terminal of each of the A-phase coil 91 and the reverse A-phase coil 92 is connected to each other, and one terminal of each of the B-phase coil 93 and the reverse B-phase coil 94 is connected to each other. The other terminal of the two sets of exciting coils 91, 92 has a transistor Q91 for switching.
~ Q94 to connect each terminal to a current source.
It is connected to both the positive terminal and the negative terminal of 95, and the excitation coils 93 and 94 are connected in the same manner.Through the transistors Q95 to Q98, the other terminal of each is connected to the current source 96. It is connected to both the positive terminal and the negative terminal. And transistor Q91
It is configured to generate a rotating magnetic field by switching the ~ Q98.

[0003]

In the above configuration,
As shown in FIG. 7, in the reverse A-phase coil 92, current flows when the phase is different from that in the A-phase coil 91, and in the B-phase coil 93, current flows when the phase is different from that of the A-phase coil 91. It is necessary to control so that current flows even in the reverse B-phase coil 94 even when the phase is different (current flowing in the A-phase coil 91 is indicated by 911, and reverse A
921 for the phase coil 92, 931 for the B phase coil 93, and 941 for the reverse B phase coil 94). Therefore, as for the currents of the current sources 95 and 96, it is necessary to control the currents as the motor body rotates, as shown by 951 and 961 in the figure, and the output currents of the two current sources 95 and 961. , 96, it is necessary to use two different current sources, which makes it indispensable to use two sets of current sources, which causes a problem that the driving device becomes large in size.

The present invention was conceived to solve the above problems, and an object thereof is to provide a driving device for a four-phase stepping motor capable of driving the four-phase stepping motor by one current source. is there.

[0005]

In order to solve the above-mentioned problems, a driving device for a four-phase stepping motor according to the present invention is one of four exciting coils of a four-phase stepping motor, and one exciting coil is an A-phase coil. An exciting coil that generates a magnetic field in a direction different by 90 degrees from the A-phase coil is a B-phase coil, an exciting coil that generates a magnetic field in a direction different by 180 degrees from the A-phase coil is an inverse A-phase coil, and a B-phase coil and a 180-degree coil. An exciting coil that generates magnetic fields in different directions is an inverse B-phase coil, and a terminal on the power supply connection side of each of the four exciting coils is a first terminal.
When the respective terminals forming a pair with the first terminal are used as the second terminals, the A-phase coil, the reverse A-phase coil, the B-phase coil and the reverse B
A driving current source for generating a direct current to be supplied to an exciting coil, and a first terminal of an A-phase coil, which are applied to a driving device in a 4-phase stepping motor in which respective second terminals of a phase coil are connected to each other. A first semiconductor switching element that opens and closes the connection with the positive terminal of the drive current source, and a first A-phase coil
A second semiconductor switching element that opens and closes the connection between the terminal of the drive current source and the negative terminal of the drive current source, and a third semiconductor switching element that opens and closes the connection between the first terminal of the reverse A-phase coil and the positive terminal, and A fourth semiconductor switching element that opens and closes the connection between the first terminal and the negative terminal of the A-phase coil, and the first of the B-phase coil
A fifth semiconductor switching element that opens and closes the connection between the terminal and the positive terminal, a sixth semiconductor switching element that opens and closes the connection between the first terminal and the negative terminal of the B-phase coil, and a reverse B-phase coil A seventh semiconductor switching element that opens and closes the connection between the first terminal and the positive terminal, and an eighth semiconductor switching element that opens and closes the connection between the first terminal and the negative terminal of the reverse B-phase coil When the combined magnetic field of the magnetic fields generated by the four sets of exciting coils is used as the combined magnetic field, the combined magnetic field is rotated by controlling the opening / closing of the first to eighth semiconductor switching elements.

[0006]

1 is a circuit diagram showing the electrical construction of an embodiment of the present invention.

In the figure, a first terminal 111, which is a power source side terminal of the A-phase coil 11, is a collector of a transistor Q1 which is a first semiconductor switching element and a collector of a transistor Q2 which is a second semiconductor switching element. Connected to the reverse A
The first terminal 121 of the phase coil 12 is connected to the collector of the transistor Q3 which is the third semiconductor switching element and the collector of the transistor Q4 which is the fourth semiconductor switching element. Further, the first terminal 131 of the B-phase coil 13 is led to the collector of the transistor Q5 which is the fifth semiconductor switching element and the collector of the transistor Q6 which is the sixth semiconductor switching element, and the first terminal 131 of the reverse B-phase coil 14 is connected. The first terminal 141 is led to the collector of the transistor Q7 which is the seventh semiconductor switching element and the collector of the transistor Q8 which is the eighth semiconductor switching element.

The second terminal 112 of the A-phase coil 11 and the second terminal 122 of the reverse A-phase coil 12 are connected to each other, and the neutral point which is the connection point is the second terminal of the B-phase coil 13. Terminal 13
2 and the second terminal 142 of the reverse B-phase coil 14 are connected to a neutral point. That is, the second terminals 112, 122, 132, and 142 of the four sets of exciting coils 91 to 94 of the A-phase coil 11, the reverse A-phase coil 12, the B-phase coil 13, and the reverse B-phase coil 14 are
Each is connected to each other.

The emitters of the transistors Q1, Q3, Q5 and Q7 are connected to the plus terminal 161 of the drive current source 16 which is a constant current source, and the emitters of the transistors Q2, Q4, Q6 and Q8 are
It is led to the negative terminal 162 of the drive current source 16. The bases of the eight transistors Q1 to Q8 are introduced into the rotation control unit 15, respectively. Then, the rotation control unit 15 has
A timing signal 151 indicating the operation timing is provided.

FIG. 2 is a timing chart showing the states of the eight transistors Q1 to Q8 and the states of the currents flowing in the four exciting coils 11 to 14, respectively.
Is an explanatory view showing a state of a generated magnetic field (currents of the exciting coils 11 to 14 in FIG. 2 are indicated as positive when current flows from the first terminal to the second terminal,
The opposite is shown as negative).

The operation of one embodiment of the present invention will be described below with reference to FIG.

In step 0, the rotation control unit 15 sets the transistors Q1 and Q4 to the ON state (FIG. 2).
Of 501 and 502). In this state, when the current value of the drive current source 16 is indicated by I, the current value I flows through the A-phase coil 11 and the current value -I flows through the reverse A-phase coil 12 (50
3, indicated by 504). No current flows through the B-phase coil 13 and the reverse B-phase coil 14. Therefore, the magnetic field generated by the A-phase coil 11 is the magnetic field shown by the vector 601 in FIG. 3, and the magnetic field generated by the inverse A-phase coil 12 is the magnetic field shown by the vector 602.
The magnetic field is given by the vector 603, which is the sum of 601 and vector 602.

When a pulse is transmitted to the timing signal 151, the step proceeds from 0 to 1, and when the step 1 is reached, the transistors Q1 and Q4 are kept in the ON state and the transistor Q8 is further turned on. Set (indicated by 505). In this state, since the drive current source 16 is a constant current source, the current value I flows through the A-phase coil 11 (506
The current value −I / 2 flows through each of the reverse A-phase coil 12 and the reverse B-phase coil 14 (shown by 507 and 508). Therefore, the magnetic field generated by the reverse A-phase coil 12 is a vector
A vector that is in the same direction as 602 and has length 1/2
The magnetic field indicated by 604 is obtained. The magnetic field generated by the inverse B-phase coil 14 has the same length as that of the vector 604 and becomes the magnetic field indicated by the vector 605 whose direction is rotated 90 degrees clockwise. Since the magnetic field generated by the A-phase coil 11 is the magnetic field indicated by the vector 606 which is the same as the vector 601, the combined magnetic field is the magnetic field indicated by the vector 607.

The electrical angle of the vector 607 with respect to the vector 603 is θ = arctan (-(-I / 2) / (I-(-I / 2))) = arctan (1 / 3) ≈ 18.4 °. This electrical angle of 18.4 ° is 4.1 ° less than the electrical angle of 22.5 °, which is obtained by dividing 360 ° of one rotation into 16 parts. This difference is caused by the non-linearity of the correspondence between the electrical angle and the mechanical angle. Since it is within the range, it is a value that can be ignored.

When a pulse is again sent to the timing signal 151 to reach the stage 2, the transistor Q5 is further turned on (indicated by 509), so that the A-phase coil 11 and the B-phase coil 13 are respectively provided. Current value I / 2 flows (51
0 and 511), reverse A-phase coil 12 and reverse B-phase coil 14
A current value -I / 2 flows through and (indicated by 512 and 513). Therefore, the A-phase coil 11 and the anti-A-phase coil 12 both generate a magnetic field indicated by the vectors 608 and 609 (the lengths of which are both half the length of the vector 601) in the same direction, and the B-phase coil 13 And the reverse B-phase coil 14 have the same length as the vector 608,
Generates a magnetic field indicated by the vectors 610, 611 whose directions are rotated 90 ° clockwise. Therefore, the combined magnetic field is vector 61 rotated by 45 ° clockwise with respect to vector 603.
It becomes the magnetic field shown by 2.

In the stage 3, since the transistor Q1 is turned off (indicated by 514) from the above state, the current value I flows in the B-phase coil 13 (indicated by 515), and the reverse A-phase coil 12 and the reverse B-phase coil are shown. A current value -I / 2 flows through 14 (shown by 516 and 517). Therefore, the B-phase coil 13 generates the magnetic field indicated by the vector 613, and the inverse A-phase coil 12 generates the vector 61.
The magnetic field indicated by 4 and the reverse B-phase coil 14 are vector 615
The magnetic field indicated by is generated, and the resultant magnetic field is the magnetic field indicated by the vector 616 rotated clockwise by 81.6 ° with respect to the vector 603 (electrical angle 7
The deviation for 7.5 ° is within a negligible range).

In the following steps 4 to 15, as shown in FIG. 2, eight transistors Q1 to Q8 are provided for each step.
ON / OFF of is set, A-phase coil 11, reverse A-phase coil 1
2, the B-phase coil 13 and the reverse B-phase coil 14 have a transistor Q
Since the currents corresponding to the ON / OFF settings of 1 to Q8 flow, the combined magnetic field in step 4 becomes the magnetic field shown by the vector 617 in FIG. 4, and the combined magnetic field in step 5 becomes the magnetic field shown by the vector 618. Then, in step 15, the combined magnetic field becomes the magnetic field shown by the vector 619, and in step 15, it becomes the magnetic field shown by the vector 620. Then, the subsequent step becomes the same as the state shown by step 0, and the same operation is repeated thereafter, so that the combined magnetic field rotates clockwise in 16 steps per cycle.

The present invention is not limited to the above embodiment, and the rotating composite magnetic field is generated when a current is applied from the first terminal 111 to the second terminal 112 of the A-phase coil 11, as shown in FIG. If the direction of the magnetic field of (shown by 621) is 0 °, a square 622 connecting the tips of the vectors 603, 617, ... Shows the combined magnetic field when the directions are 0 °, 90 °, 180 °, and 270 °. Since the strength of the magnetic field is indicated by the vector whose tip reaches the side of, and the strength of the composite magnetic field is a magnetic field whose strength varies depending on the direction, the current value of the driving current source 16 is made variable (step 0 Compared to the current value at step 4,
Same current value for 8 and 12, about 1.41 for steps 2, 6, 10, and 14.
Double the current value, and in steps 1, 3, 5, 7, 9, 11, 13, 13, the current value is approximately 1.26 times higher), so that the strength of each combined magnetic field can be made uniform. Is.

The first to eighth semiconductor switching devices have been described using the transistors Q1 to Q8, but the same applies to other semiconductor switching devices such as thyristors. It is possible to

[0020]

According to the driving device of the four-phase stepping motor of the present invention, the second terminals of the A-phase coil, the reverse A-phase coil, the B-phase coil and the reverse B-phase coil are connected to each other, and the first Each of the terminals is connected to the plus terminal and the minus terminal of the drive current source through the semiconductor switching elements provided correspondingly, and the rotation control unit controls the opening and closing of these semiconductor switching elements. As a result, since the composite magnetic field is rotated, it is possible to drive the four-phase stepping motor with only one current source.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 2 is a timing chart showing the open / close state of each of the eight semiconductor switching elements and the state of the current flowing through each of the four exciting coils.

FIG. 3 is an explanatory diagram showing a state of a generated magnetic field.

FIG. 4 is an explanatory diagram showing a state of a generated magnetic field.

FIG. 5 is an explanatory diagram showing a state of a generated magnetic field.

FIG. 6 is a circuit diagram showing an electrical configuration of a conventional technique.

FIG. 7 is an explanatory diagram showing a relationship between a current flowing through an exciting coil and a current of a current source according to a conventional technique.

[Explanation of symbols]

 11 A-phase coil 111 1st terminal 112 2nd terminal 12 Reverse A-phase coil 121 1st terminal 122 2nd terminal 13 B-phase coil 131 1st terminal 132 2nd terminal 14 Reverse B-phase coil 141 1st 1st terminal 142 2nd terminal 16 Driving current source 161 Plus terminal 162 Minus terminal Q1 1st semiconductor switching element Q2 2nd semiconductor switching element Q3 3rd semiconductor switching element Q4 4th semiconductor switching element Q5 5th Semiconductor switching element Q6 6th semiconductor switching element Q7 7th semiconductor switching element Q8 8th semiconductor switching element

Claims (1)

[Claims] 1. Four sets of exciting coils of a four-phase stepping motor, one exciting coil is an A-phase coil, and an exciting coil for generating a magnetic field in a direction different from the A-phase coil by 90 degrees is a B-phase coil. The exciting coil that generates a magnetic field in a direction different by 180 degrees from the A-phase coil is an inverse A-phase coil, and the exciting coil that generates a magnetic field in a direction different by 180 degrees from the B-phase coil is an inverse B-phase coil. The first terminal on the power supply connection side of each excitation coil is the first
And the respective terminals forming a pair with the first terminal as the second terminals, the second terminals of the A-phase coil, the reverse A-phase coil, the B-phase coil and the reverse B-phase coil are A drive device in a four-phase stepping motor connected to each other, wherein a drive current source for generating a direct current to be supplied to the exciting coil, a first terminal of the A-phase coil and a positive terminal of the drive current source are connected. A first semiconductor switching element that opens and closes a second semiconductor switching element that opens and closes a connection between the first terminal of the A-phase coil and the negative terminal of the drive current source, and a first terminal of the reverse A-phase coil A third semiconductor switching element that opens and closes the connection between the positive terminal and the positive terminal, a fourth semiconductor switching element that opens and closes the connection between the first terminal of the inverted A-phase coil and the negative terminal, and a fourth semiconductor switching element of the B-phase coil. Connect the terminal of 1 and the positive terminal A fifth semiconductor switching element that opens and closes; a sixth semiconductor switching element that opens and closes the connection between the first terminal of the B-phase coil and the negative terminal; and a first terminal of the reverse B-phase coil and the positive terminal. And a seventh semiconductor switching element that opens and closes a connection between the first and second terminals of an inverted B-phase coil and the negative terminal, and is generated by the four sets of excitation coils. A driving device for a four-phase stepping motor, characterized in that when the magnetic field obtained by synthesizing the generated magnetic field is used as the synthetic magnetic field, the synthetic magnetic field is rotated by controlling opening / closing of the first to eighth semiconductor switching elements.