JP3370886B2 - Motor control signal generator and motor controller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control signal generator for generating a motor control signal necessary for controlling a brushless motor and a motor control device using this device.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open No. 2-159994 discloses a rotor sensor that outputs a phase signal used to obtain a phase switching signal for switching an excitation phase of a brushless motor, and a rotary encoder that outputs a speed detection signal. There is disclosed a motor control device including a phase loss detection circuit that detects a phase loss of an output signal of a rotary encoder, determines an abnormality of the rotary encoder, and stops the motor. In the phase loss detection circuit of this conventional device, a combination state signal consisting of multiple bits is created based on the phase signal output from the rotor sensor, and the speed detection signal output from the rotary encoder is detected during the period when the combination state signal is generated. Counting the number of signal pulses, if the count value is less than or equal to the specified value, a phase loss has occurred (the rotary encoder has an error).
Therefore, the motor is stopped. The abnormality detection technology of the rotary encoder described in this publication uses a combination state signal created based on the phase signal output from the rotor sensor as a reset signal of the addition / subtraction counter that counts the speed detection signal output from the encoder. Same as using.

Regarding a technique for detecting an abnormality of the rotary encoder, Japanese Patent Laid-Open No. 57-39312 discloses a similar technique. In this technique, a C-phase pulse signal output from a rotary encoder (a signal output only once during one rotation of the encoder) is used as a reset signal of an addition / subtraction counter that counts a speed detection signal output from the encoder. There is.

[0004]

Problems to be Solved by the Invention JP-A-57-3931
In the technique disclosed in Japanese Patent Laid-Open No. 2 (1994), since the high-precision C-phase pulse signal output from the encoder is used as the reset signal of the addition / subtraction counter, the abnormality detection accuracy of the rotary encoder is high. However, since the C-phase pulse signal is output only once per rotation, the abnormality cannot be detected until the rotor makes one rotation.

On the other hand, in the technique disclosed in Japanese Unexamined Patent Publication No. 2-159994, since the reset signal of the addition / subtraction counter is generated based on the phase signal output from the rotor sensor, the rotor is rotated by one revolution. In between, multiple reset signals can be generated. However, the output accuracy of the rotor sensor is lower than the output accuracy of the encoder, the reset signal generation accuracy deteriorates, and as a result, the abnormality detection accuracy deteriorates.

It is an object of the present invention to provide a motor control signal generator having a high abnormality detection accuracy and having a function of detecting an abnormality of a rotary encoder before the rotor makes one revolution.

Another object of the present invention is to provide a motor control signal generator having a function of detecting an abnormality of a rotor sensor.

Another object of the present invention is to provide a motor control device having a high abnormality detection accuracy and having a function of detecting an abnormality of a rotary encoder before the rotor makes one revolution.

[0009]

SUMMARY OF THE INVENTION A motor control signal generator and a motor control device to which the present invention is directed include an n-phase (n-phase).
Is a positive integer greater than or equal to 3) A-phase pulse that is provided with a rotor sensor that outputs a phase signal for n phases used to obtain a phase switching signal that switches the excitation phase of a brushless motor, and a rotary encoder that is 90 degrees out of phase Signal and a B-phase pulse signal and a C-phase pulse signal generated once per rotation, and an m-phase A-phase pulse signal and a B-phase pulse signal based on the A-phase pulse signal and the B-phase pulse signal.
A multiplication signal generation circuit that outputs a multiplication signal (speed detection signal) of multiplication (m is a positive integer of 2 or more) and an abnormality detection circuit that outputs an abnormality detection signal when an abnormality of the rotary encoder is detected are provided. The abnormality detection circuit determines an abnormality of the rotary encoder based on the count value of the addition / subtraction counter that adds / subtracts the multiplication signal according to the rotation direction of the motor and the count value of the addition / subtraction counter when the reset signal that resets the addition / subtraction counter is input. And an abnormality determination circuit that outputs a detection signal. The motor control device further includes a motor control unit that controls the brushless motor based on the outputs from the rotor sensor, the encoder device, the multiplication signal generation circuit, and the abnormality detection circuit.

In the present invention, as a rotary encoder,
The fixed-cycle pulse signal generated in a cycle shorter than half the generation cycle of the C-phase pulse signal is output from the same output line as the C-phase pulse signal so as not to overlap with the C-phase pulse signal. A rotary encoder (which is configured to generate a pulse signal including a periodic pulse signal and a C-phase pulse signal) is used. As such a rotary encoder, for example, when an optical rotary encoder including a rotary plate having a plurality of slits for generating an A-phase pulse signal, a B-phase pulse signal and a C-phase pulse signal is used, A plurality of slits are formed at equal intervals on a concentric circle with the slit for generating the C-phase pulse signal so as not to overlap with the slit for forming the slit of this optical rotary encoder. By doing so, the fixed-cycle pulse signal is generated at a cycle of 1/2 or less of the C-phase pulse signal based on the plurality of slits.
It is output from the same output line as the phase pulse signal. Generally speaking, the cycle of the fixed-cycle pulse signal is a cycle of 1 / p (p is a positive integer of 2 or more) of the cycle in which the C-phase pulse signal is output. For example, when the brushless motor is three-phase excitation, it is preferable to set the interval between the slits so as to generate the constant-cycle pulse signal at a cycle of ¼ of the cycle at which the C-phase pulse signal is output. As will be described later in detail, in the present invention, this constant period pulse signal is used as a reset signal for the addition / subtraction counter. In particular, in the case of an optical rotary encoder, it is necessary to increase the size of the rotating plate only by forming slits for generating a fixed-cycle pulse signal in a slit array forming slits for obtaining a C-phase pulse signal. The periodic pulse signal (reset signal) can be easily generated with high accuracy.

In the present invention, since the fixed-cycle pulse signal is used as the reset signal, the phase relationship between two or more phase signals of the phase signals for n phases output from the rotor sensor and the pulse signal output from the output line. Further includes a pulse signal separation circuit for separating the C-phase pulse signal and the constant-cycle pulse signal from the pulse signal output from the output line to separately output the C-phase pulse signal and the constant-cycle pulse signal. . Then, the abnormality detection circuit uses the fixed-cycle pulse signal separated by the pulse signal separation circuit as a reset signal.

If the pulse signal separation circuit is provided, even if the C-phase pulse signal and the constant period pulse signal are output from the same output line, the constant period pulse signal output from the encoder device is used as the reset signal of the addition / subtraction counter. Can be used.

According to the present invention, since the fixed-cycle pulse signal having a short cycle of 1/2 or less of the generation cycle of the C-phase pulse signal output from the encoder device is used as the reset signal of the addition-subtraction counter, the addition-subtraction counter is reset. It can be performed with high accuracy. Further, since the reset signal is output a plurality of times while the rotor makes one rotation, the abnormality of the rotary encoder can be detected early.

The method of detecting the abnormality judgment by the abnormality judgment circuit is arbitrary, but for example, when the motor is rotating in the same direction in the abnormality judgment circuit, is the count value of the addition / subtraction counter between the reset signals larger than the specified value? If the rotary encoder is abnormal, the abnormality of the rotary encoder is determined. When the rotation direction of the motor is changed, the abnormality of the rotary encoder is determined by whether or not the count value of the addition / subtraction counter becomes 0 first after the rotation direction is changed. You may comprise. According to the present invention, since the addition / subtraction counter can be reset with high accuracy, the accuracy of detecting an abnormality by such a determination method is significantly higher than that of the related art.

In the abnormality determining circuit, when the motor is rotating in the same direction, when the count value of the addition / subtraction counter between the reset signals is larger than the upper limit specified value which is larger than the specified value, and when it is larger than the specified value. It may be configured to determine that an abnormality has occurred in the rotor sensor when it is smaller than the small lower limit specified value. When an abnormality occurs in the rotor sensor, some of the phase signals are High or Lo.
It is fixed to w. When this happens,
When the C-phase pulse signal and the fixed-cycle pulse signal are separated by the pulse signal separation circuit, the C-phase pulse signal and the fixed-cycle pulse signal cannot be accurately separated, and the C-phase pulse signal is used as a reset signal. , Part of the fixed-cycle pulse signal is output. Therefore, the reset signal generation cycle is partially extremely short, or the reset signal generation cycle is partially extremely long. Therefore, as described above, by setting the upper limit specified value or the lower limit specified value that is larger than the specified value for detecting the abnormality of the rotary encoder, and comparing them with these specified values, the abnormality of the rotor sensor is detected. It can be detected that it has occurred.

It should be noted that the abnormality determination circuit does not have the abnormality detection function of the rotor sensor, but is based on the change in the generation mode of at least one of the C-phase pulse signal and the fixed-cycle pulse signal output from the pulse signal separation circuit. A rotor sensor abnormality detection circuit for detecting abnormality of the rotor sensor may be separately provided. As described above, when an abnormality occurs in the rotor sensor, the C-phase pulse signal may appear multiple times per revolution, or the period of the fixed-cycle pulse signal may become extremely short or extremely long. To do. Therefore, if the rotor sensor abnormality detection circuit detects this phenomenon, it is possible to detect the abnormality of the rotor sensor.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of an embodiment of a motor control device of the present invention. In the figure, 1 is an AC power supply, 2 is a rectifier circuit, 3 is a smoothing capacitor, 4 is a motor drive circuit, 5 is a three-phase brushless motor, 6 is a rotor sensor for detecting the rotor position of the motor 5, and 7 is a rotary. It is an encoder. Reference numeral 8 is a phase switching control circuit, 9 is a quadruple multiplication circuit as a multiplication signal generation circuit, and 10 is an abnormality detection circuit. Reference numeral 11 is a motor control circuit, 12 is a base drive circuit, and both circuits 11 and 12 constitute a motor control unit.

The operation of the motor controller having the above structure will be described. The rotor sensor 6 outputs phase signals U, V, W for three phases used to obtain a phase switching signal for switching the excitation phase of the brushless motor 5 (U, V, W in FIG. 6).
W signal). The rotary encoder 7 includes an A-phase pulse signal and a B-phase pulse signal whose phases are different by 90 degrees, a C-phase pulse signal generated once per rotation (see a signal C of CD in FIG. 6), and a C-phase pulse signal. Is a encoder device that outputs a fixed-cycle pulse signal (see reset signal D of C-D in FIG. 6) that is generated in a cycle shorter than ½ of the generation cycle. The fixed-cycle pulse signal D is output from the same output line as the C-phase pulse signal so as not to overlap with the C-phase pulse signal (see CD in FIG. 6). The A-phase and B-phase pulse signals output from the rotary encoder 7 are input to the quadrupling circuit 9 and converted into quadrupling pulse signals,
The quadruple pulse signal is input to the motor control circuit 11 to detect the speed of the motor 5.

U, which is output from the rotor sensor 6,
The V and W signals are input to the phase switching control circuit 8, and the phase switching control circuit 8 inputs to the base drive circuit 12 a phase switching signal that determines the energization of the motor stator winding to be energized. The base drive circuit 12 outputs a drive signal to the drive circuit 4 that drives the motor 5 based on the speed detection signal from the motor control circuit 11 and the phase switching signal from the phase switching control circuit 8 to output the speed of the motor 5. Take control.

The abnormality detecting circuit 10 counts the 4 × pulse signal output from the 4 × circuit 9 during the generation interval or generation period of the fixed period pulse signal D output from the rotary encoder 7, and outputs the count value. An abnormality of the rotary encoder 7 is detected depending on whether is larger or smaller than a specified value.

For example, when the A-phase and B-phase pulse signals output from the rotary encoder 7 are out of phase (when no pulse signal is output), the pulse signals output from the quadruple multiplication circuit 9 are counted for the above period. Abnormality detection circuit 1
In the case of 0, the count value is smaller than the specified value, so it is determined that the phase A or the phase B is missing, and a motor stop signal is output to the base drive circuit 12 to stop the motor 5. Further, when noise is mixed in the A-phase and B-phase pulse signals output from the rotary encoder 7 and the number of pulse signals increases, the count value becomes larger than the specified value. The abnormality detection circuit 10 determines from this detection that an abnormality has occurred and outputs a motor stop signal to the base drive circuit 12 to stop the motor 5. Note that the specified value is 1
If the value is limited to one value, the motor may stop due to the instantaneous generation of noise, and thus the specified value may have a range. Since the A-phase and B-phase pulse signals are less likely to be out of phase due to the occurrence of noise, for example, when the count value differs from a certain value R by 2 or more (the specified value in this case is R to R + 2), it is abnormal. It may be determined that the occurrence has occurred.

Next, a specific embodiment of the essential part of the motor control signal generator of the present invention will be described. In FIG. 2, 13 is a light emitting element of a rotary encoder, 14 is a rotary slit, 15 is a fixed slit, and 16 is a light receiving element. Reference numeral 17 is a pulse conversion circuit, and 10 is an abnormality detection circuit. The light emitted from the light emitting element 13 is a rotary slit plate 14 and a fixed slit plate 1 fixed to the shaft of the motor.
5 through each slit formed, the rotary slit 14
An optical signal having a brightness and darkness corresponding to the rotation of the plate is generated and supplied to the light receiving element 16. The light receiving element 16 converts light and dark of light into intensity of current and supplies it to the waveform shaping circuit of the pulse conversion circuit 17.

The light receiving element 16 is composed of, for example, six elements 16a to 16c and 16a 'to 16c' as shown in FIG. 3, and the output signal of the light receiving element 16b is 90 degrees out of phase with the light receiving element 16a. It is located in. The rotary slits are arranged so that the output of the light receiving element 16a and the output from the light receiving element 16a 'are 180 degrees out of phase with each other, and the outputs thereof are subtracted from each other to obtain a sharper rising and falling waveform. . The same applies to the outputs of the light receiving elements 16b and 16b '. The light receiving elements 16a and 16a 'are for obtaining an A phase pulse signal, and the light receiving elements 16b and 16b' are for obtaining a B phase pulse signal. In addition, the light receiving element 16
c and the light-receiving element 16c 'include one C-phase pulse signal per rotation of the rotary slit 14 and the above-mentioned fixed-cycle pulse signal D.
1 to D4. The arrow in the figure indicates the direction of rotation of the rotary slit.

FIG. 4 shows an example of the rotary slit plate 14 provided with the rotary slit of the rotary encoder used in the present invention. In the figure, 28 is a rotating plate and 14A is A.
Reference numeral 14B is a rotary slit for obtaining a phase pulse signal, 14B is a B phase pulse signal, and 14C is a rotary slit for obtaining a C phase pulse signal. These rotary slits are provided with a plurality of rotary slits 14A and 14B arranged in parallel in the circumferential direction on three circles having different radii, and one rotary slit 14C is provided.
The rotary slits 14D ... Are the above-mentioned fixed-cycle pulse signals D1 to D1.
It is a rotary slit for obtaining D4, and this rotary slit is spaced at an appropriate interval from the slit 14C at a position on the same circumference as the rotary slit 14C, and in this example, the four slits 14D are equidistant. Are arranged as follows. Based on these slits 14D, the fixed-cycle pulse signals D1 to D have a fixed cycle of 1/4 of the generation cycle of the C-phase pulse signal.
4 is output from the same output line as the C-phase pulse signal.

Next, an example of the pulse conversion circuit 17 and the abnormality detection circuit 10 in FIG. 2 will be described with reference to FIG. Figure 5
In, 6 is a rotor sensor, 16A, 16B, 16C
Are the light receiving elements 16 to 16c 'as shown in FIG.
The A-phase signal, the B-phase signal, and the C-phase signal (including the fixed-cycle pulse signals D1 to D4) obtained from FIG. Further, 17 is a pulse conversion circuit of FIG. 2 and 10 is an abnormality detection circuit. Blocks 18 to 20 included in the pulse conversion circuit 17 are all waveform shaping circuits, a block 21 is a direction determination and quadruple multiplication circuit, and 22 is a pulse signal separation circuit. Reference numeral 23 is an addition / subtraction counter for adding / subtracting the multiplication signal according to the rotation direction of the motor, 24 is a register, 25 is a determination unit, and
6 constitutes an abnormality determination circuit.

The structure and operation of the apparatus shown in FIG. 5 will be described below.
The A-phase pulse output is shaped through the waveform shaping circuit 18,
It is added to the direction determination and quadruple multiplication circuit 21. The B-phase pulse output, which is 90 degrees out of phase with the A-phase pulse output, is similarly shaped through the waveform shaping circuit 19 and applied to the direction determination and quadruple multiplication circuit 21. Direction discrimination and quadrupling circuit 21
In (1), the rotation direction of the rotary slit is determined from the relationship between the waveform levels of the two pulse signals input from the waveform shaping circuits 18 and 19. That is, the waveform shaping circuit 19
At the rising edge of the output waveform of, the rotation direction is determined depending on whether the output of the waveform shaping circuit 18 is at the high level or the low level. Further, in the direction discriminating and quadrupling circuit 21, a pulse is generated at the rising and falling points of the output signals of the waveform shaping circuits 18 and 19, and the rotation direction discriminated by the discriminating method for the quadruple frequency signal, That is, it outputs to separate terminals according to the clockwise direction or the counterclockwise direction.
These different direction outputs are added and subtracted by counters 2
3 is input to the addition input or the subtraction input.

On the other hand, the rotary slits 14C and 14D shown in FIG.
C-phase pulse signal generated once per rotation by the rotation of
The fixed-cycle pulse signals D1 to D4, which are generated in a cycle shorter than 1/2 of the generation cycle of the C-phase pulse signal, are output from the same output line as the C-phase pulse signal so that they do not overlap each other [see FIG. ) CD pattern], waveform shaping circuit 2
Input to 0. The C-phase pulse signal and the fixed-cycle pulse signal D shaped through the waveform shaping circuit 20 are input to the pulse signal separation circuit 22.

On the other hand, from the rotor sensor 6, in this example, 3
Phase signals U, V, W for three phases used to obtain a phase switching signal for switching the excitation phase of the phase brushless motor [Fig.
(See (A) to (C)] is input to the pulse signal separation circuit 22. The pulse signal separation circuit 22 is based on the phase relationship between the phase signals for the three phases from the rotor sensor 6 and the pulse signal input from the waveform shaping circuit 20.
The C-phase pulse signal and the fixed-cycle pulse signal D are separated from the pulse signal [CD pattern of FIG. 6 (C)] input from 0, and these signals are separately output. The pulse signal separation circuit 22 is composed of a combination of logic circuits as shown in FIG. 7, for example. The U-phase and V-phase pulse signals of FIGS. 6A and 6B are input to the prohibiting circuit 22a of FIG. 7 as shown, and the U * V pulse signal of FIG. 6E is output from the output terminal. Let This signal is input as a switching signal to the AND circuit 22b and the inhibition circuit 22c as shown in the figure. On the other hand, the AND circuit 22b and the prohibition circuit 22c are each supplied with a pulse signal of the CD pattern shown in FIG. Then, the AND circuit 22b outputs the C-phase pulse signal [FIG. 6 (F)], and the prohibiting circuit 22c outputs the fixed-cycle pulse signals D1 to D4 [FIG. 6 (G)]. The outputs of the above-described fixed-cycle pulse signals D1 to D4 are input to the addition / subtraction counter 23 and the register 24, and the counter 23
And a reset signal for resetting the register 24. The addition / subtraction counter 23 counts the multiplied signals output from the quadruple multiplication circuit 21 during the generation cycle or generation interval of the fixed-cycle pulse signal, and sets the count value in the register 24. When the motor is rotating in the same direction, the determination unit 25 determines whether the register 24 is operating as described above.
The abnormality of the rotary encoder is determined depending on whether the count value set in is larger or smaller than a predetermined specified value. When the rotation direction of the motor is switched, the count value becomes 0 after the rotation direction is switched (the count value reset by the reset signal generated first after the rotation direction is switched is 0
It is determined whether the rotary encoder is abnormal. The fact that this count value is not 0 means that the pulse signal output from the rotary encoder is small or large, which means that the rotary encoder has an abnormality.

Further, in the judging section 25, when the motor is rotating in the same direction, the upper limit of the count value of the addition / subtraction counter 23 between the constant period pulse signals (for example, D1-D2) is larger than the specified value. When it is larger than the specified value,
And when it is smaller than the lower limit specified value that is smaller than the specified value, it is determined that an abnormality has occurred in the rotor sensor 6.
When an abnormality occurs in the rotor sensor 6, in FIG.
For example, the U-phase signal remains High, the V-phase signal remains Low, and so on. If the U-phase signal remains High, the U * V signal in FIG. 6E remains Low, and the D1, C, and D3 signals are output as reset signals. In this state, the interval between the pulse signal D1 and the pulse signal C is set to the normal pulse interval (D1
-D2), and the interval between the pulse signal C and the pulse signal D3 or the pulse signal D3 and the pulse signal D1.
Is longer than the normal pulse interval (D1-D2). If the V-phase signal remains low,
Only the pulse signals D2 and D4 are output as reset signals, and the interval between the pulse signals D2 and D4 is longer than the normal pulse interval (D1-D2). Therefore, a lower limit specified value (for example, ⅔ of one normal cycle) is set with reference to the interval between the pulse signal D1 and the pulse signal C.
Of the pulse signals D2 and D4 (two cycles) as a reference, and an upper limit specified value (for example, 4/3 of one normal cycle) (Count value to be counted in) is defined. These lower limit reference value and upper limit reference value are values that can be distinguished from the specified values used when determining the abnormality of the rotary encoder.The lower limit reference value is smaller than the above specified value and the upper limit specified value is the above specified value. Is a larger value.

When determining the abnormality of the rotary encoder or the rotor sensor, the determination section 25 outputs an abnormality detection signal for stopping the motor. Further, the determination unit 25
Determines whether the abnormality is in the rotary encoder or the rotor sensor. When it is determined that the rotor sensor is abnormal, the fact may be displayed by a lamp display, a buzzer display, or the like.

In this example, the judging section 25 detects the occurrence of an abnormality in the rotary sensor from the count value. However, in addition to the judging section 25, the C-phase pulse signal and the fixed period pulse output from the pulse signal separation circuit are output. The rotor sensor 6 is based on a change in the generation mode of at least one of the signals.
A rotor sensor abnormality detection circuit for detecting the abnormality may be provided. When an abnormality occurs in the rotor sensor 6, two or more C-phase pulse signals are output during one rotation, or the generation cycle of the fixed cycle pulse signal becomes uneven. Therefore, the abnormality of the rotor sensor 6 can be detected by observing the change in the generation mode of at least one of the C-phase pulse signal and the fixed-cycle pulse signal output from the pulse signal separation circuit. It should be noted that how to configure such a rotor sensor abnormality detection circuit is arbitrary.

In the above-described embodiment, the three-phase brushless motor is used, and the rotor sensor that outputs the phase signals for three phases is used. However, in the present invention, the brushless motor has n phases (n is 3 or more). The rotor sensor may be any one as long as it outputs a phase signal for n phases used to obtain a phase switching signal for switching the excitation phase of an n-phase brushless motor.

Further, the multiplication signal generating circuit may be any one that outputs a multiplication signal of m multiplications (m is a positive integer of 2 or more) of the A phase pulse signal and the B phase pulse signal.

Further, in the above-described embodiment, the generation period of the constant period pulse signal is 1/4 of the generation period of the C-phase pulse signal.
However, the generation cycle of the fixed-cycle pulse signal may be a fixed cycle shorter than 1 / P (P is a positive integer of 2 or more) of the generation cycle of the C-phase pulse signal.

[0036]

According to the motor control signal generator of the present invention, since the constant period pulse signal is used as the reset signal of the addition / subtraction counter, the addition / subtraction counter can be reset with high accuracy. As a result, the abnormality detection accuracy of the rotary encoder can be made significantly higher than in the conventional case. Further, since the reset signal is output a plurality of times during one rotation of the rotor, it is possible to detect the abnormality of the rotary encoder earlier than in the conventional case.

Further, according to the motor control device of the present invention,
Quickly and accurately detect abnormalities in the rotary encoder,
The drive of the brushless motor can be controlled extremely well.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an embodiment of a motor control device according to the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration example of a motor control signal generation device of the present invention.

FIG. 3 is an explanatory diagram showing a layout of the light receiving elements of FIG.

FIG. 4 is an explanatory diagram showing a configuration example of a rotary plate of a rotary encoder used in the present invention.

FIG. 5 is a block diagram showing an example of an embodiment of a main part of a motor control signal generation device according to the present invention.

6A to 6G are signal waveform diagrams for explaining the operation of the pulse signal separation circuit in FIG.

FIG. 7 is a circuit diagram showing a specific configuration example of the pulse signal separation circuit of FIG.

[Explanation of symbols]

4 Motor drive circuit 5 brushless motor 6 Rotor sensor 7 Rotary encoder 8-phase switching control circuit 9 multiplication signal generation circuit 10 Abnormality detection circuit 11 Motor control circuit 12 Base drive circuit 13 Light emitting device 14 Rotating slit plate 14A A-phase pulse slit 14B B-phase pulse slit 14C C-phase pulse slit 14D fixed-cycle pulse slit 16, 16a to 16c Light receiving element 17 Pulse conversion circuit 18 to 20 waveform shaping circuit 21 Direction Discrimination and Quadrupling Signal Generation Circuit 22 pulse signal separation circuit 23 Addition / subtraction counter 24 registers 25 Judgment section 26 Abnormality judgment circuit 28 rotating plate

Front Page Continuation (72) Inventor Shoji Ito 1-5-11-1 Kitaotsuka, Toshima-ku, Tokyo Sanyo Electric Co., Ltd. (56) Reference JP-A-6-26883 (JP, A) JP-A-5 -118871 (JP, A) JP-A-4-25716 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01D 5/00-5/62 H02P 6/00-6/02

Claims (7)

(57) [Claims] 1. A rotor sensor for outputting a phase signal for n phases used to obtain a phase switching signal for switching an excitation phase of an n-phase (n is a positive integer of 3 or more) brushless motor, and a rotary encoder. 90 degrees out of phase A
An encoder device that outputs a phase pulse signal and a B phase pulse signal and a C phase pulse signal that occurs once per rotation, and the A phase pulse signal and the B phase pulse based on the A phase pulse signal and the B phase pulse signal A multiplied signal generation circuit for outputting a multiplied signal of m times the signal (m is a positive integer of 2 or more),
An abnormality detection circuit that outputs an abnormality detection signal when detecting an abnormality of the rotary encoder, wherein the abnormality detection circuit resets the addition and subtraction counter that adds and subtracts the multiplication signal according to the rotation direction of the motor, and the addition and subtraction counter. A motor control signal generator comprising: an abnormality determination circuit that determines the abnormality of the rotary encoder from the count value of the addition / subtraction counter when a reset signal is input and outputs the abnormality detection signal. The rotary encoder uses the same output line as the C-phase pulse signal so that a constant-cycle pulse signal generated at a cycle shorter than 1/2 of the generation cycle of the C-phase pulse signal does not overlap with the C-phase pulse signal. And output from the output line and two or more phase signals of the phase signals for the n phases. Based on the phase relationship with the pulse signal, the C-phase pulse signal and the fixed-cycle pulse signal are separated from the pulse signal output from the output line to separate the C-phase pulse signal and the fixed-cycle pulse signal. A motor control signal device, further comprising a pulse signal separation circuit for outputting, wherein the addition / subtraction counter uses the fixed-cycle pulse signal separated by the pulse signal separation circuit as the reset signal. 2. The rotary encoder is an optical rotary encoder including a rotary plate having a plurality of slits for generating the A-phase pulse signal, the B-phase pulse signal and the C-phase pulse signal. In addition, a plurality of slits are formed on the rotary plate in a concentric circle with the slits for generating the C-phase pulse signal at equal intervals so as not to overlap with the slits, and based on the plurality of slits. 1/2 of the generation cycle of the C-phase pulse signal
2. The motor control signal device according to claim 1, wherein the fixed-cycle pulse signal is output from the same output line as the C-phase pulse signal at the following fixed cycles. 3. A rotor sensor for outputting a phase signal for three phases used to obtain a phase switching signal for switching the excitation phase of a three-phase brushless motor, an A-phase pulse signal having a rotary encoder and 90-degree different phases, and An encoder device that outputs a B-phase pulse signal and a C-phase pulse signal that is generated once per rotation; a multiplication signal generation circuit that outputs a 4 times multiplication signal based on the A-phase pulse signal and the B-phase pulse signal; An abnormality detection circuit that outputs an abnormality detection signal when an abnormality of the rotary encoder is detected, and the abnormality detection circuit is configured to detect the abnormality according to the rotation direction of the motor.
An addition / subtraction counter for adding / subtracting a multiplication signal, and an abnormality determination circuit for determining an abnormality of the rotary encoder from the count value of the addition / subtraction counter when a reset signal for resetting the addition / subtraction counter is input, and outputting the abnormality detection signal. A rotary encoder having a plurality of slits for generating the A-phase pulse signal, the B-phase pulse signal, and the C-phase pulse signal. It comprises an optical rotary encoder having a plate, and a plurality of slits are formed on the rotary plate at equal intervals on a concentric circle so as not to overlap with the slit for generating the C-phase pulse signal. The interval between the plurality of slits is a quarter of the generation period of the C-phase pulse signal, and It is determined that a periodic pulse signal based on a number of slits is generated, and based on a phase relationship between two phase signals of the phase signals for the three phases and a pulse signal output from the output line, A pulse signal separation circuit that separates the C-phase pulse signal and the fixed-cycle pulse signal from the pulse signal output from the output line to separately output the C-phase pulse signal and the fixed-cycle pulse signal, A motor control signal generator, wherein the addition / subtraction counter uses the fixed-cycle pulse signal separated by the pulse signal separation circuit as the reset signal. 4. The abnormality determination circuit, when the motor is rotating in the same direction, determines whether the rotary encoder has an abnormality depending on whether the count value of the addition / subtraction counter between the reset signals is larger or smaller than a specified value. When the rotation direction of the motor is switched, the abnormality of the rotary encoder is determined depending on whether or not the count value of the addition / subtraction counter becomes 0 after the rotation direction is switched. The signal generator for motor control according to claim 1 or 2. 5. The abnormality determination circuit, when the motor is rotating in the same direction, when the count value of the addition and subtraction counter between the reset signals is larger than an upper limit specified value larger than the specified value, and The motor control signal generation device according to claim 3, wherein when the lower limit value smaller than the specified value is smaller than the lower limit value, it is determined that an abnormality has occurred in the rotor sensor. 6. A rotor sensor abnormality detection for detecting abnormality of the rotor sensor based on a change in a generation mode of at least one of the C-phase pulse signal and the fixed-cycle pulse signal output from the pulse signal separation circuit. The signal generator for motor control according to claim 1, further comprising a circuit. 7. A rotor sensor for outputting a phase signal for n phases used to obtain a phase switching signal for switching an excitation phase of an n-phase (n is a positive integer of 3 or more) brushless motor, and a rotary encoder. 90 degrees out of phase A
An encoder device that outputs a phase pulse signal and a B phase pulse signal and a C phase pulse signal that occurs once per rotation, and the A phase pulse signal and the B phase pulse based on the A phase pulse signal and the B phase pulse signal A multiplied signal generation circuit for outputting a multiplied signal of m times the signal (m is a positive integer of 2 or more),
An abnormality detection circuit that outputs an abnormality detection signal when an abnormality of the rotary encoder is detected, and a motor that controls the brushless motor based on outputs from the rotor sensor, the encoder device, the multiplication signal generation circuit, and the abnormality detection circuit. A control unit, wherein the abnormality detection circuit, the addition and subtraction counter for adding and subtracting the multiplication signal according to the rotation direction of the motor, and the count value of the addition and subtraction counter when a reset signal for resetting the addition and subtraction counter is input. Is a motor control device configured to determine an abnormality of the rotary encoder and output the abnormality detection signal, wherein the rotary encoder is 1 / P of a generation cycle of the C-phase pulse signal. (P is a positive integer of 2 or more) It is configured to output the C-phase pulse signal and the fixed-cycle pulse signal from the same output line so as not to overlap with the phase pulse signal, and based on the phase relationship with two or more signals of the n-phase signal. And a pulse signal separation circuit for separating the C-phase pulse signal and the fixed-cycle pulse signal from the pulse signal output from the output line to separately output the C-phase pulse signal and the fixed-cycle pulse signal. The motor control device, wherein the addition / subtraction counter uses the fixed-cycle pulse signal separated by the pulse signal separation circuit as the reset signal.