JPH01218399A - Motor controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applicable to office automation (
^) Concerning control devices for motors used in equipment.

[Prior Art] An encoder having an integer multiple of the number of magnetic poles of a rotor, and a counting means for counting the number of detected parts of the encoder as the rotor rotates at a predetermined location on the stator side. Conventionally, the motor drive signal generator of the motor control device, which switches the energization to the stator coil when the count value of matches the predetermined value, uses a digital comparator to compare the count value and the predetermined value, and when the two match, A flip-flop, such as a clock generating means, was configured to generate a coil energization signal from a pulse generated by a digital comparator.

[Problem to be Solved by the Invention J] However, in such a motor drive signal generator, once the flip-flop is no longer in a normal operating state due to malfunction or electrical noise, it cannot be repaired, and the counter must be reset to initialize. The problem was that I had to start over from scratch.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device that solves these problems, has excellent noise resistance, and is capable of reliable operation.

[Means for Solving the Problems] To achieve this, the present invention provides an encoder that is fixed to the shaft of a rotor and has a detected portion that is an integral multiple of the number of magnetic poles of the rotor, and an encoder that is fixed to the shaft of a rotor and has a detected portion that is an integral multiple of the number of magnetic poles of the rotor, and In a motor control device comprising a counting means for counting a number, and a means for switching energization to a stator coil when a count value of the counting means matches a predetermined value, the means corresponds to a numerical value indicated by the counting means. The present invention is characterized in that it includes a plurality of digital comparators that take an output state, and a motor drive signal generating means that generates a coil energization signal corresponding to the output state.

[Function] In the present invention, the digital comparator compares the count value and the set value and outputs only when a certain state is reached, and the motor drive signal generating means generates a coil energization signal according to the state of the output. .

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. - (First Embodiment) FIGS. 1 to 15 show a first embodiment of the present invention.

First, FIG. 1 is a drive control circuit diagram of a motor according to the present embodiment, and FIGS. 2 and 3 are a perspective view and a cross-sectional view, respectively, showing a configuration example of the motor according to the first embodiment of the present invention. be.

In FIGS. 2 and 3, reference numeral 201 is a motor capable of stepwise rotation and has a built-in magnetic encoder.

This motor 201 has a stator 204 having a structure in which two stators 202 and 203 having magnetic hollow rings are stacked one above the other. The surfaces of the stators 202 and 203 are made of magnetic material, and the inner periphery has magnetic pole pieces (20 in the stator 203) for forming N and S magnetic poles alternately in the circumferential direction.
5.206 as an example, stator 202 as 207,208
A bobbin 21 in which a large number of wires (exemplified in ) are formed alternately at minute intervals, and a conductive wire 209 is wound in a hollow part inside the bobbin 209 in a large number of turns.
0 is inserted.

The magnetic pole pieces (205, 20[i, 207, 208) are arranged and fixed in two stages, upper and lower, so as to face each other in the axial direction. Magnetic pole pieces (205, 206, 207, 208
) is formed to be equal to the circumferential magnetic pole width of the magnet rotor 211. The magnetic pole pieces 205 and 207 are each formed by extending the magnetic material portions on the lower surfaces of the stators 202 and 203 upward toward the inner periphery, and are also formed to be shifted by a quarter pitch from each other. Moreover, the magnetic pole pieces 206 and 208 are each formed by extending the magnetic portions of the upper surfaces of the stators 202 and 203 toward the inner circumference downward, and are also formed one-fourth of a pitch apart from each other. 212 and 213 respectively represent the stator 202.
This is a lead wire connected to the conductor wire 203.

A cylindrical magnet rotor 211 is fixed to a rotating shaft 214 and rotates together with the rotating shaft 214. This magnet rotor 211 has bearings 2 mounted respectively on flanges 215, 216 welded to the stator 202, 203.
17, 218, thereby rotatably disposed within the inner hollow portion of the stator 204). The magnet rotor 211 may be a plastic magnet or a sintered magnet, and any suitable magnet may be used. On the outer periphery of the magnet rotor 211, N and S magnetic poles are alternately radially oriented and magnetized to face the magnetic pole pieces (205, 206, 207, and 208).

The rotating shaft 214 is arranged to protrude from the lower end of a bearing 218 attached to a flange 216 welded to the stator 202, and N and S are provided at minute intervals around the entire circumference of the protruding portion of the rotating shaft 214. A magnetic encoder 219 with 288 magnetic poles alternately magnetized is attached. A magnetic sensor (MR element) 220 is configured to output A-phase and B-phase signals with an electrical phase shift of 90° at a location facing the magnetic pole portion 224 (periphery) of the magnetic encoder 219.
is installed.

This magnetic sensor (MR element) 220 is connected to a fixed member 222
The output signal is sent to the control circuit shown in the first diagram via a lead wire 223 soldered on the board 221. 225 is a metal cup-shaped magnetic encoder storage case fixed to the stator 202, and a fixing member 222 to which a magnetic sensor (M11 element) 220 is fixed is attached to the bottom of the inner surface. In addition, the magnetic pole portion 224 and magnetic sensor (MR element) inside this storage case 225
This prevents dirt and dust from adhering to the surface of the 220.

In this embodiment, the number of magnetic poles of the magnet rotor 211 is 24.
The number of magnetic poles of the magnetic encoder 219 is an integral multiple of 288 poles. Therefore, the number of encoder output pulses per rotor pole is 12.

In this example, the rotation angle per pulse of the encoder output is 1.25 degrees/pulse (360 degrees/288 pulses), which is a sufficiently small value for the rotation angle of 15 degrees of one rotor pole. . In other words, even without any adjustment, the error in the position between the encoder output pulse and the rotor magnetic pole is at most ±
It is 0.625 degrees, which is about 4 degrees per rotor pole.
The error is 2%, which is a value that can be completely ignored. The relationship between the number of encoder output pulses and the number of rotor magnetic poles may be set within a permissible error range, and the number of encoder output pulses per rotation of the rotor may be an integral multiple of the number of rotor magnetic poles. In general, an error of ±12.5% is sufficient;
In that case, the number of pulses will be four times the number of rotor magnetic poles.

In addition, when the number of rotor magnetic poles is 100, such as in a hybrid step motor, and when the number of encoder output pulses and the number of rotor magnetic poles correspond one-to-one, as with conventional Hall elements or other encoders, , precise adjustment is required to align both. However, according to this embodiment, by setting the number of encoder output pulses to 400 to 500, the motor having the hybrid step motor structure can function like a DC brushless motor without the above-mentioned alignment. This level of output pulse number can be easily achieved using a magnetic encoder and magnetoresistive element (MR element) with a magnetization pattern of wavelength QJ of 34 μm and a diameter of 26.6non (structured as shown in Figures 2 and 3). can.

FIG. 1 shows an example of the configuration of a motor control circuit configured as described above. In FIG. 1, 220A and 220B are the second
Magnetoresistive element (MR element) indicated by 220 in the figure and FIG. 3, 103 and 104 are differential amplifiers, 105°1
06 is a comparator, 107 is an up-down clock generator that generates the UP clock and DOWN clock according to this embodiment, 108 is an up-down (UP-DOWN) counter, 109 is a motor drive signal generator, 110 is a motor drive circuit, 11! is a position detection counter, 112 is an external control device, 113 is a speed control reference (X generator, 114
is the motor speed controller.

The operation of the drive circuit will be explained with reference to this figure.

The Mll element 220A, as shown in FIG. 4(A),
Four magnetoresistive elements "1 to r4" are arranged along the magnetic pole array direction of the ff1 pole part 224. In the figure, the MR element 2208 is shown by a solid line, and the MR element 220B is shown by a dotted line.

Elements rl to r4 are connected in a bridge configuration as shown in FIG. 4(B), and generate an output voltage according to changes in the external magnetic field. Note that this FIG. 4 (II) shows the MR element 220A.
The same applies to the MR element 220B, although only this is shown.

The four elements constituting the other MR element 220B are 1. 4 of MIl element 220A
The elements r1 to ``4'' are arranged in the middle.

In this example, since the MR element is placed facing the magnetic encoder attached to the motor shaft, a waveform as shown in Fig. 5 is obtained in response to the magnetic field fluctuation caused by the magnetic encoder as the motor rotates. . Since two Ml elements are arranged with a phase shift of 178 periods with respect to the s magnetic period of the magnetic encoder, when one MR element 2208 has a waveform shown by the symbol soi in FIG.
The II element 220B, as shown by reference numeral 502 in FIG.
A waveform whose phase is electrically shifted by 90' is obtained.

These waveforms are amplified by differential amplifiers 103 and 104 in the next stage, and then converted into signals 503 (corresponding to waveform 501) and 504 in FIG. 9 by comparators 105 and 106.
The waveform is shaped into a square wave shown in (corresponding to waveform 502),
Next, it is input to the UP-DOWN clock generator 107.

This clock generator 107 has two clock generators as shown in FIG.
Consists of two D-type flip-flops 601 and 602,
Two input terminals 603, . 6
04, mouth P, and two output terminals 605, 60 of DOWN.
6, and generates the tlP clock or DOWN clock depending on the phase between the human input signals A and B (details will be described later).

Figure 7 shows waveforms 603 and 604 of signals A and B, and up-D
6 is a diagram showing the relationship with OWN output waveforms 605 and 606. FIG. In addition, the two arrows in the figure indicate the IJP direction or DOWN direction.
Shows the flow of time in the direction.

Now, in Fig. 7, the UP force direction signals A and B are clock generators! 07, the major general number 701 in Figure 7 is entered.
Two waveforms shown at 702 appear at the UP-DOWN output terminals. That is, pulses corresponding to the surroundings of the magnetic encoder appear only at the IIP terminal, and nothing is output from the DOWN terminal. Conversely, when pulse signals A and B seen from the DOWN direction in FIG. 7 are input, the signal 703
, 704° are output to the UP and DOWN terminals. In other words, the phase relationship of the signals output from the two MR elements is determined by the rotational direction of the rotor to be one of the two arrows in FIG. 7, so the output corresponding to the rotational direction is used to generate the UP-DOWN clock. It is output from the device 107.

Next, the UP-DOWN signal is 2-) (7)
IIP-DOWN counter 1 (18 and 1] 1- is input. IIP-DOWN counter 108 is 5 bi
It is a radix 24 counter of t, which counts up or down according to the manual UP clock signal 121 or DOWN clock signal 122, and counts from "0" to "" in decimal notation.
23" is expressed as a 5-bit signal in binary representation (each signal is BO, Bl.

B2. B3, 84) is output to the output terminal.

The output of the counter 108 is input to a motor drive signal generator 109.

The motor drive signal generator 109, as shown in FIG.
4 digital comparators 801.802.803
.

804, clock generator 8051 rotation direction switch 806
゜It consists of a start/stop controller 807. The start/stop controller 807 is configured, for example, as shown in FIG.
S) has OR circuits 1101-1104 that receive the signal and signals 816-819, respectively.

Digital comparator 801.802.803.804
compares the preset value with the manually inputted data, and outputs “1” if the set value is greater than the input value,
In other cases, that is, when the values are the same or when they are smaller, "0" is output. Therefore, by setting one of the numerical values from "0" to "23" in decimal notation in 5 binary bits to the four digital comparators, the value corresponding to the value indicated by the υP-DOWN counter 108 is set. The output state is determined.

Figure 1O shows the comparison values of each digital comparator, a=O,
b=6. c=12. The respective outputs 808, 809, 810, and 811 when d=18 are shown. These outputs are input to clock generator 805.

Figures 11 and 12 show two configurations of the clock generator.
This is an example, and is composed of two or four exclusive OR circuits. Now set the clock generator to the first
As shown in Figure 1, the digital comparator 801
．． Signal 808 output from 802.803.804,
809, 810, and 811 are input to corresponding terminals, respectively.

At this time, if the clock generator has the configuration shown in FIG. 11, the output signals of the two exclusive ON circuits 901 and 902 and the inverted signals from the inverters 903 and 904 are outputted from 1302, 1303, and 130 in FIG. 13(A).
4. A lock signal like 1305 is output. Therefore, these outputs correspond to the output states (
808, 809, 810, 811) (in addition, 1301 is the up-oowN counter 108
This is a human clock signal waveform, and the number above it indicates the current value).

At this time, even if noise enters the circuit, the output of the digital comparator and the output of the clock generator will only contain temporary noise and will immediately return to the original pattern, so the motor will not run out of control. Moreover, since the response speed of the motor is slow, there is no actual effect on rotation.

This signal 1302.1303.1304.1305 is 2
Represents the energization signal to the phase coil 2021.2031,
A each.

B, τ, expressed in hundreds. The A, B, A, and B signals are applied to the motor drive circuit 110 to energize the coils 2021 and 2031.

The A-phase coil 2031 is the tlP-DOWN counter 1
When the manual clock to 08 is “0” or “12”, the B-phase coil 2021 also outputs IIP-DOWN counter 1.
The direction of energization is switched when the 08 henojin clock is "6" or "18".

Focusing on the l-phase, the direction of energization is switched every 12 pulses, in other words, the energization is switched every 180 degrees in electrical angle.

The timing of energization switching is based on the magnetic poles of the rotor and the output value of the UP-DOWN counter 108 with reference to the position of the stator magnetic poles, and the mode of speed control is as follows.

That is, the rotor rotational speed signal 120 obtained based on the output signal from one magnetoresistive element 220B is compared with the signal 133 from the speed control reference signal generator 13, and the rotor is adjusted so as to eliminate the difference between the two. control the speed of

As soon as the rotor speed becomes slower than the set value (the value indicated by the speed control reference signal 133), the signal 134 from the comparator circuits 1 and 4 is used to generate a signal from the phase compensation circuits 115 and 115. Voltage control circuit 1
Coil 2021 in motor drive circuit 110 via 16
．． The applied voltage to 2031 is increased to speed up the rotation of the rotor, and conversely, when the speed becomes faster than the set value, the applied voltage is lowered to keep the rotor speed constant.

By the way, the comparison value of the digital comparator can be arbitrarily set by the control signal 130 from the external control device 112.

That is, in this embodiment, since the encoder pulses are subdivided into 12 pulses per magnetic pole of the rotor, the energization timing can be changed from the normal energization timing.

FIG. 13(B) shows a case where the energization timing is accelerated, and the phase is advanced from the normal energization timing (FIG. 13(A)).

FIG. 13(C) shows a case where the energization timing is delayed, and the phase is delayed from the normal energization timing (FIG. 13(A)).

By advancing or delaying the phase in this manner, optimal control can be performed when the speed is unstable due to rotor acceleration/deceleration, load fluctuations, etc.

For example, if the setting value of the digital comparator 801 is a=23
, the same <802 as b=5, the same <803 as C=11, the same <804 as d=j7, and each comparator output 808
.about.811 is input manually to the clock generator 805 in FIG. 805 output signals 812-81
Obtained as 5. Similarly, the comparison value of the comparator is a=
1. 'b=7. c=13. When d=19, output signals 812 to 815 having waveforms whose phases are delayed by one pulse are obtained, which are shown at 1312 to 1315 in FIG. 13(C). In other words, the external signal 130 can be used to arbitrarily UP-DOW.
Four output signals 812-815 with phases corresponding to the count value of the N counter are obtained by the clock generator 805.

The output signal button of clock generator 805 can be changed by changing the internal configuration of clock generator 605. For example, if the clock generator 805 is configured using exclusive OR circuits 1001 to 1004 as shown in FIG.
For = output signals 812 to 815 as shown in Fig. 14 (^)
, (B) and (C) (indicated by symbols 1402-1405, 1407-1410 and 1412-1415, respectively) are obtained. As will be explained later, the waveform pattern in Figure 13 obtained by the clock generator in Figure 11 is a signal for driving the step motor with two-phase excitation, and the waveform pattern in Figure 14 is for driving with one-phase excitation. This is the signal.

Next, the output signals 812-815 of the clock generator are
As shown in the figure, the rotation direction switch 806 is manually operated. The rotation direction switching device 806 is composed of four multiplexers, and outputs the human power signals by distributing them according to the motor rotation direction instruction signal 129 from the external control device 112. For example, an OR circuit 1101 provided in the start/stop controller 807 may be
-llig all output signals 124 to 127 of 1104
The motor can be stopped by changing to the h'' state.

In FIG. 1, 110 indicates two stators 202°20
Coil 2021.203 consisting of conductor 209 provided in 3
1, which is a bipolar drive circuit in this example. This motor drive circuit 1
10 is the output signal 1 from the motor drive signal generator 109
The motor is rotated forward or reverse based on steps 24 to 126.

In addition, the signal from the magnetic sensor (MR element) 220
- The rotor position can be known by counting with the DOWN counters 108 and 111, but the position where the rotor's magnetic poles and the stator's magnetic poles are facing each other when the power is turned on (initial setting) before driving the motor is set as the initial state, and the outputs of the UP-DOWN counters 108 and 111 are set to MO''.After this, even if the motor is stopped, this setting remains valid as long as the power to the circuit is not turned off.

Specifically, one phase of the two-phase coils 2021 and 2031 is energized in a fixed direction. At this time, the magnetic poles of the stator phase on the energized side and the magnetic poles of the rotor magnet face each other, and at this point the IIP-DOWN counter 108
Reset signals 131 and 132 are applied from external control device 112 so that the outputs of 11.1 and 11.1 become "O". By this operation, it is possible to obtain a position information signal in which the rotor position is subdivided into 1/12 based on the opposing point between the rotor magnetic pole and the stator magnetic pole, and furthermore, the rotor position is divided into 1/12.
The position of the rotor can be known based on the output values of the N counters 108 and 111, and it is possible to switch the energization to the coils.

Furthermore, if the clock generator 805 shown in FIG. 12 is used, the energization timings shown in FIGS. 14(^) to (C) can be obtained. In Figure 14 (^), 1401
is the encoder output waveform, 1402, 1403, 1404
1405 represents the energized state of the two-phase coils 2021 and 2031, and represents four signals A, B, A, and B, respectively. In this case, the A phase is tlP-DOWN counter 10
When the output of 8 is "0", "6", 12", "18",
Also, in the B phase, the output of the UP-DOWN counter 108 is “0”.
”.

The energization and the direction of energization are switched at 6'', 12, and 18°.

In this case, energization is switched every 90 degrees in terms of electrical angle.

This energization method is similar to the bipolar drive single sum dynamic magnetic force method.

Compared to the 180° energization method (Fig. 12) described above, the energization time is shorter, so the current flowing through the coil is localized, but the rotational torque obtained is approximately 1/7T.
Ru. This is similar to the comparison between two-phase excitation and one-phase excitation of a normal motor, and can be used depending on driving conditions and the like. Even in the case of energization every 90°, the phase of the energization timing described above can be changed in the same way (Fig. 14 (B)
, see (C)).

Note that, as shown in FIG. 15, four coils 1201.
1202, 1203, and 1204, and add the first
By applying four drive signals 124, 125, 126, and 127 from the illustrated motor drive signal generator 109, the motor illustrated in FIGS. 2 and 3 can be driven unipolarly. The drive signal energization method used is the same as the bipolar drive (Fig. 1). This can also be used depending on driving conditions and the like.

゛As explained above, by detecting the rotor position using an encoder signal that is subdivided into 1/12 per pole compared to the number of magnetic poles of the rotor, rotor speed control is stabilized and optimal control can be performed. Can be done. Moreover, since encoder signals are counted, the energization timing can be switched accurately. Furthermore, the rotational position of the rotor can be detected and the position can be controlled.

According to the operation explanation above, the rotor position is determined by the encoder,
Monitoring is performed based on the combination of MR elements, and when the stator magnetic pole and rotor magnetic pole match, the excitation button is switched, so the original step motor characteristics are lost and D
Although C motor characteristics are realized, operation as a step motor is also possible by changing the drive circuit.

That is, FIG. 16 shows its drive circuit, which is the circuit of FIG. 1 plus an excitation button generator 1501. Signal switch 1
502 has been added.

An excitation button generator 1501 generates excitation signals 1503, 1504, 1505, and 1506 for two-phase step motors in synchronization with a drive clock signal 1507 from an external control device 112.
Output. Also, the rotation direction 18 of the external control device 112
No. 1508 and excitation method switching signal 1509 enable switching of the direction of movement of the bang and output of one-phase and two-phase excitation patterns. The 1-phase excitation pattern is shown in Figure 14 (8).
The two-phase excitation pattern is the same as the four-waveform shown in FIG. 13(A).

Signal switch! 502 are output signals 124, 125, 126, 127 from the motor drive signal generator 109 and output signals 1503, 1504 from the excitation button generator 1501.
, 1505, 1506. That is, by selecting the former using the drive switching signal 1510 from the external control device 112, an OC motor-like operation can be realized, and by selecting the latter, a step motor-like operation can be realized. This also serves as an example of the initial setting of the motor counter described above. That is, the initial setting of the counter is performed using one phase of a two-phase motor as an example, but this can be easily achieved by setting the motor drive to stepping mode and selecting the l-phase excitation button.

(Second Embodiment) In this embodiment, digital comparators 801.802
.

803.804 compares the set value and the data value and outputs "1" only when the set value is smaller.

In FIG. 17, the set value is a = 23. b=5. c=1
1. Digital comparator output 8 when d=17
0a.

809.810,811. By inputting these outputs to the corresponding terminals of the clock generator shown in FIG. 11 or 12, a lock signal as shown in FIG. 13 (^) or FIG. 14 (A) is output.

Therefore, these outputs are uniquely determined by the output states (808, 809, 810, 811) of the fourth digital comparator at count values (decimal) from 0" to "23".

Also in this embodiment, by manipulating the value of the digital comparator with an external signal, tlP-DOW can be controlled arbitrarily.
Four output signals 812 to 815 are obtained whose phases correspond to the count value of the N counter.

[Effects of the Invention] As described above, according to the present invention, it is possible to realize a motor control circuit that has excellent noise resistance and operates reliably.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a motor control device according to a first embodiment of the present invention, and FIGS. 2 and 3 are a perspective view and a sectional view, respectively, showing an example of the configuration of a motor applicable to this embodiment. , Figure 4(A) shows the MR element and encoder in this example.
. - Figure 4 (B) is an equivalent circuit diagram of the MR element according to this example, Figure 5 is a waveform diagram showing the output signal of the MR element, and Figure 6 is this example A circuit diagram showing an example of the configuration of the IIP-DOWN clock generator, FIG. 7 is a timing chart showing the human output signal of the same generator, FIG. 8 is a circuit diagram showing an example of the configuration of the motor drive signal generator, FIG. 9 is a circuit diagram showing an example of the configuration of a start-stop control device, FIG. 1O is a waveform diagram showing the output waveform of the digital comparator according to this embodiment, and FIG. 11 is an example of the configuration of a clock generator according to this embodiment. Figure 12 is a circuit diagram showing another example of the configuration of the clock generator according to this embodiment. Figures 13 and 14 are IIP diagrams corresponding to Figures 11 and 12, respectively. -A timing chart showing the relationship between the DOWN counter output and the energization switching signal; Fig. 15 is a unipolar drive circuit diagram of the motor; Fig. 16 is a circuit diagram showing an example of the configuration of a switching circuit between continuous drive and step drive; FIG. 17 is a waveform diagram for explaining the second embodiment of the present invention. 220.22OA, 220B...M-mouth element, 107.
・・Up/down clock generator, lα8,111-U
P-DOWN counter, 109... Motor drive signal generator, 112... External control device, 801.802.803.804... Digital comparator, 2!2, 213, 2021.2031... Coil, 211... Rotor, 202.203... Stator. Figure 2 Figure 3 Figure 4 (B) Figure 5 6! "9M604 B Figure 7 Figure 9 Figure 16 Procedural Amendment May 25, 1999

Claims (1)

[Claims] 1) An encoder that is fixed to the shaft of a rotor and has a detected part that is an integral multiple of the number of magnetic poles of the rotor, and a counter that counts the number of detected parts of the encoder as the rotor rotates. and means for switching energization to the coils of the stator when the count value of the counting means matches a predetermined value, wherein the means outputs an output corresponding to the numerical value indicated by the counting means. A motor control device comprising: a plurality of digital comparators that change states; and a motor drive signal generating means that generates a coil energization signal corresponding to the output state.