JP6973992B2 - Rotation detection device, motor device and rotation detection method - Google Patents

Description

The present invention relates to a rotation detection device, a motor device, and a rotation detection method.

Conventionally, there is a motor device that detects a rotation angle (rotation position) of a motor by using an optical encoder and controls the rotation of the motor by using the detected result.

The optical encoder has a wheel in which a plurality of slits are formed, and the larger the number of slits, the higher the resolution.

Japanese Unexamined Patent Publication No. 2015-90309

Here, in order to increase the resolution, it is conceivable to make improvements such as forming more slits in the wheel. In order to form more slits on the wheel, it is necessary to reduce the size of one slit to make it a minute slit. However, there is a problem that the cost increases when trying to form many minute slits.

The present invention has been made in view of the above, and an object of the present invention is to provide a rotation detection device, a motor device, and a rotation detection method capable of detecting a rotation angle with high resolution without improving an encoder. do.

To solve the above problems and achieve the object, the rotation detecting device according to one embodiment of the present invention, an encoder for detecting the intermittent rotation angle of the angle of rotation of the rotor, the rotation angle by the front Symbol encoder The first voltage of the signal corresponding to the rotation of the rotating body at the first timing in which is detected, and the rotation angle detected by the encoder at the second timing after the first timing. The second voltage of the signal corresponding to the rotation of the rotating body at the second timing and the third voltage of the signal corresponding to the rotation of the rotating body at the third timing after the second timing. The first difference showing the difference between the first voltage and the second voltage, the second difference showing the difference between the second voltage and the third voltage, and the first difference. The detection unit includes a detection unit that detects the rotation angle of the rotary body at the third timing based on the first rotation angle corresponding to the above, and the detection unit outputs a signal corresponding to the rotation of the rotary body. Among the signals of the three-phase Hall elements to be output, the Hall signal having the largest absolute tilt value at the third timing is selected, and the value of the selected Hall signal at the first timing is the value of the first voltage. The value of the selected Hall signal at the second timing is defined as the second voltage, and the value of the selected Hall signal at the third timing is defined as the third voltage at the third timing. The rotation angle of the rotating body is detected .

According to one aspect of the present invention, the rotation angle can be detected with high resolution without improving the encoder.

FIG. 1 is a diagram showing an example of a configuration of a motor device according to an embodiment. FIG. 2 is a diagram showing an example of a signal used in high resolution detection processing. FIG. 3 is a flowchart showing an example of the flow of the high resolution detection process according to the embodiment. FIG. 4 is a diagram for explaining the high resolution detection process. FIG. 5 is a diagram for explaining the process of step S102 in the high resolution detection process.

Hereinafter, the rotation detection device, the motor device, and the rotation detection method according to the embodiment will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a diagram showing an example of a configuration of a motor device according to an embodiment. As shown in the example of FIG. 1, the motor device 1 includes a motor 10, a rotation detection device 15, and a drive circuit 16.

The motor 10 is incorporated into a device (for example, a copier, a personal computer, etc.) used for automating and streamlining office work and the like, and a machine used for automating various work and processes in a factory. It is incorporated in. Hereinafter, the case where the motor 10 is an inner rotor type three-phase brushless DC (direct-current) motor will be described, but the type of the motor 10 is not limited to this. The motor 10 is rotated by a drive signal described later from the drive circuit 16.

The motor 10 includes a rotor 10a. The motor 10 rotates when the rotor 10a rotates. The rotor 10a is an example of a rotating body.

The rotation detection device 15 includes an encoder 11, magnetic sensors 12a, 12b, 12c, operational amplifiers (arithmetic amplifiers) 13a, 13b, 13c, and a microcomputer 14.

The encoder 11 detects the rotation angle (rotation position) of the motor 10 (rotor 10a). The encoder 11 outputs a signal corresponding to the rotation of the motor 10 (rotor 10a). For example, the encoder 11 outputs a signal from the A phase and a signal from the B phase to a counter 14a described later according to the rotation of the motor 10 (rotor 10a). Hereinafter, the case where the encoder 11 has a resolution of 400 P / R (Pulse per Round) will be described, but the resolution of the encoder 11 is not limited to this. In this case, the encoder 11 detects an intermittent rotation angle of every 0.9 (360/400) degrees among the rotation angles of the motor 10 (rotor 10a).

For the magnetic sensors 12a, 12b, 12c, for example, a Hall element is used. The magnetic sensors 12a, 12b, 12c are fixedly arranged at predetermined positions in the vicinity of the rotor 10a. The magnetic sensors 12a, 12b, and 12c output U-phase, V-phase, and W-phase differential signals HU + / HU−, HV + / HV−, and HW + / HW−, which change according to the magnetic field of the rotor 10a, respectively. The U-phase, V-phase, and W-phase differential signals HU + / HU−, HV + / HV−, and HW + / HW− are analog signals having a phase difference of 120 degrees from each other.

The operational amplifier 13a outputs a Hall signal HU that can be input to the A / D (Analog to Digital) converter 14b from the differential signals of HU + and HU−. The operational amplifier 13b outputs a hall signal HV that can be input to the A / D converter 14b from the differential signals of HV + and HV−. The operational amplifier 13c outputs a hall signal HW that can be input to the A / D converter 14b from the differential signals of HW + and HW-. The Hall signals HU, HV, and HW are signals corresponding to the rotation of the motor 10 (rotor 10a).

In the present embodiment, the microcomputer 14 includes a counter 14a, an A / D converter 14b, and a CPU (Central Processing Unit) 14c, but the counter 14a and the A / D converter 14b are external to the microcomputer 14. May be placed in.

The counter 14a outputs an encoder signal by counting the rising / falling position of the signal from the A phase output from the encoder 11 and the rising / falling position of the signal from the B phase.

The A / D converter 14b converts the Hall signals HU, HV, and HW output from the operational amplifiers 13a, 13b, and 13c into digital signals and outputs them. From this point onward, these signals are actually processed as digital numerical values, but for convenience of operation explanation, HU, HV, and HW are expressed as voltages to proceed with the explanation.

The CPU 14c is connected to a speed command signal generation unit (not shown) which is an external device. The CPU 14c finally generates a drive control signal from the speed command signal input from the speed command signal generation unit. The speed command signal is a signal generated by the speed command signal generation unit, and is command information for designating the target rotation speed of the motor 10. Specifically, the speed command signal is a pulse signal in which the number of pulses is the number of rotation steps and the number of pulses per unit time is the rotation speed. The speed command signal generation unit generates, for example, a clock signal having a frequency corresponding to the target rotation speed as a speed command signal by pulse frequency modulation (PFM), and outputs the clock signal to the CPU 14c. The CPU 14c generates a PWM signal for rotating the motor 10 at a rotation speed corresponding to a speed command signal, for example, by pulse width modulation (PWM).

The CPU 14c generates a PWM signal based on the encoder signal output by the counter 14a together with the speed command signal. For example, the CPU 14c compares the count number of the speed command signal with the count number of the encoder signal while the motor 10 is rotating by inputting the speed command signal. When the count numbers are different, the CPU 14c generates a PWM signal in which the duty ratio is changed so that the count numbers match. The CPU 14c may control the rotation speed of the motor 10 by using the hall signals HU, HV, and HW instead of the encoder signal output by the counter 14a while the motor 10 is rotating. ..

The CPU 14c generates a drive control signal for driving the inverter circuit of the drive circuit 16 described later based on the control by the generated PWM signal, and outputs the drive control signal to the inverter circuit. As the drive control signal, for example, six types of switching signals corresponding to each switch element of the inverter circuit are output. By outputting these drive control signals, the switch elements corresponding to the respective drive control signals operate on and off, the drive signal is output to the motor 10, and power is supplied to each phase of the motor 10. The motor 10 rotates.

Further, the CPU 14c adjusts the timing for switching the on / off operation of each switch element of the inverter circuit based on the Hall signals HU, HV, and HW.

The drive circuit 16 is connected to a DC power supply (not shown), generates a drive signal from the drive control signal generated by the CPU 14c, and outputs the drive signal to the motor 10. For example, the drive circuit 16 includes an inverter circuit. The inverter circuit outputs a drive signal to the motor 10 based on the drive control signal output from the CPU 14c, and energizes the three armature coils included in the motor 10. In the inverter circuit, for example, a pair of a series circuit of two switch elements provided at both ends of a DC power supply is arranged for each phase (U phase, V phase, W phase) of the three armature coils. It is composed. In each pair of the two switch elements, the terminals of each phase of the motor 10 are connected to the connection points between the switch elements.

Further, the CPU 14c according to the present embodiment detects the rotation angle of the motor 10 (rotor 10a) with high resolution by executing the high resolution detection process.

FIG. 2 is a diagram showing an example of a signal used in high resolution detection processing. In the example of FIG. 2, the signal 21 from the A phase output from the encoder 11, the signal 22 from the B phase, and the Hall signal HU output from the A / D converter 14b, which are signals used in the high resolution detection process, are shown. HV and HW are shown. In the example of FIG. 2, the horizontal axis represents time and the vertical axis represents voltage.

The signal 21 from the A phase and the signal 22 from the B phase have a phase difference of 90 degrees. The signal 21 from the A phase and the signal 22 from the B phase are signals in which a pulse having a rising edge and a falling edge is formed. Hereinafter, when the description is given without distinguishing between the rising edge and the falling edge, the “rising edge and falling edge” are simply referred to as “edge”. When the encoder 11 has a resolution of, for example, 400 P / R, the motor 10 (rotor 10a) rotates 0.9 (360/400) degrees between the edges of the signal 21 from the A phase and the signal 22 from the B phase. Means things. That is, in the signal 21 from the A phase and the signal 22 from the B phase, each time the rotation angle of the motor 10 (rotor 10a) becomes a specific rotation angle among a plurality of intermittent specific rotation angles. It is a signal having an edge.

The Hall signals HU, HV, and HW are signals that change according to the magnetic field of the rotor 10a. That is, the Hall signals HU, HV, and HW are signals corresponding to the rotation of the motor 10 (rotor 10a). The Hall signals HU, HV, and HW have a phase difference of 120 degrees from each other.

FIG. 3 is a flowchart showing an example of the flow of the high resolution detection process according to the embodiment. The high-resolution detection process is performed by the CPU 14c when detecting the rotation angle of the motor 10 (rotor 10a) at a timing other than the edge timing of the signal 21 from the A phase and the signal 22 from the B phase (hereinafter, timing T3). Is executed by. That is, the timing T3 is a timing different from the timing at which the rotation angle is detected by the encoder 11. The CPU 14c that executes the high-resolution detection process is an example of the detection unit, and detects the rotation angle at the timing T3. Further, the timing T3 is an example of the third timing.

As shown in the example of FIG. 3, the CPU 14c first waits for the designation of the timing T3 (step S101). The CPU 14c waits for the edge of the signal 21 from the A phase or the signal 22 from the B phase (step S102) until it is specified (step S101: No), and when an edge occurs (step S102: Yes), the previous timing. The voltage at T2 is specified as the voltage at timing T1 (step S103), then the voltage at timing T2 is specified (step S104), and the process returns to step S102. Here, the timing T2 is a timing before the timing T3, and is temporally at the timing T3 among the plurality of timings of the edge of the signal 21 from the A phase and the edge of the signal 22 from the B phase. It is the closest timing to. Further, the timing T1 is a timing before the timing T2, and is temporally at the timing T2 among a plurality of timings of the edge of the signal 21 from the A phase and the edge of the signal 22 from the B phase. The closest timing. The CPU 14c performs this operation for all of the hall signals HU, HV, and HW for each edge timing. Further, as can be seen from the operation, in order to specify both the voltages at the timings T2 and T1 prior to the designation of the timing T3, at least two or more processes are required.

Then, when the timing T3 is specified (step S101: Yes), the CPU 14c specifies the voltage of the hall signal (step S105). The CPU 14c performs this operation for all of the hall signals HU, HV, and HW. After that, the CPU 14c has a larger absolute value of the slope (rate of change) of the hall signals HU, HV, and HW from the voltages at the timings T2 and T1, preferably the absolute value of the slope. The largest Hall signal is selected (step S106). FIG. 4 is a diagram for explaining the high resolution detection process. In FIG. 4, the Hall signals HU, HV, HW up to the timing T3, the signal 21 from the A phase, and the signal 22 from the B phase are shown on the upper side. Further, FIG. 4 is an excerpt of a part of the Hall signal HU, the signal 21 from the A phase, and the signal 22 from the B phase in the time range from the timing just before the timing T3 to the timing T3. An enlarged view is shown at the bottom. For example, in FIG. 4, the CPU 14c calculates the absolute value of the slope at the timing T3 for each of the hall signals HU, HV, and HW, and selects the hall signal HU having the largest absolute value of the slope.

FIG. 5 is a diagram for explaining the process of step S106 in the high resolution detection process. For example, in the example of FIG. 5, when the timing T3 is within the range of the time T11 or more and less than the time T12, the CPU 14c selects the hall signal HW having the largest absolute value of the slope. Further, when the timing T3 is within the range of the time T12 or more and less than the time T13, the CPU 14c selects the Hall signal HV having the largest absolute value of the slope. Further, when the timing T3 is within the range of the time T13 or more and less than the time T14, the CPU 14c selects the Hall signal HU having the largest absolute value of the slope. Further, when the timing T3 is within the range of the time T14 or more and less than the time T15, the CPU 14c selects the hall signal HW having the largest absolute value of the slope. Further, when the timing T3 is within the range of the time T15 or more and less than the time T16, the CPU 14c selects the Hall signal HV having the largest absolute value of the slope. Further, when the timing T3 is within the range of the time T16 or more and less than the time T17, the CPU 14c selects the Hall signal HU having the largest absolute value of the slope. The same applies even if the timing T3 is a timing within a time range other than the time range described above.

That is, in step S106, the CPU 14c selects a Hall signal whose signal shape is closest to a straight line (linear) at the timing T3. Therefore, in the present embodiment, the CPU 14c is a simple process of selecting the Hall signal having the largest absolute value of the slope among the Hall signals HU, HV, and HW, and the shape of the signal becomes the closest to the straight line at the timing T3. Hall signals can be selected. Therefore, according to the present embodiment, it is possible to easily select a hall signal whose signal shape is closest to a straight line.

Further, regardless of the timing of the timing T3, as described with reference to FIG. 5 above, there is a hall signal whose signal shape is closest to a straight line. Therefore, the CPU 14c can select a hall signal whose signal shape is closest to a straight line regardless of the timing of the timing T3.

As shown in the example of FIG. 5, as a result, in step S106, the CPU 14c selects a hall signal included in the range R determined by the intersection of the hall signals HU, HV, and HW at the timing T3. Become. Note that the range R is not always constant because the waveforms of the Hall signals HU, HV, and HW may change due to individual differences of the magnetic sensors 12a, 12b, and 12c, environmental conditions, and the location of each intersection. Although it may not be possible, the hall signal closest to the straight line can be selected at any time by the above method.

The timing T2 described above has already been specified here (steps S102 to S104).

FIG. 4 shows a case where the CPU 14c selects the hall signal HU at the timing T3 in the previous step S106 as described above. For example, as shown in the enlarged view described above in FIG. 4, in steps S103 to 104, the CPU 14c is at a timing before the timing T3, at the timing of the falling edge of the signal 22 from the B phase. Specify a certain timing T2. The timing T2 is an example of the second timing, which is the timing at which the rotation angle of the motor 10 (rotor 10a) is detected by the encoder 11.

Further, the timing T1 described above has already been specified here (steps S102 to 104).

For example, as shown in the enlarged view described above in FIG. 4, in steps S102 to 104, the CPU 14c is at a timing before the timing T2, at the timing of the falling edge of the signal 21 from the A phase. Specify a certain timing T1. The timing T1 is an example of the first timing, which is the timing at which the rotation angle of the motor 10 (rotor 10a) is detected by the encoder 11.

As described above, the CPU 14c specifies the voltage V3 at the timing T3 in the selected Hall signal in step S105, and specifies the voltage V2 at the timing T2 and the voltage V1 at the timing T1 in steps S102 to 104. The voltage V1 at the timing T1 is an example of the first value, the voltage V2 at the timing T2 is an example of the second value, and the voltage V3 at the timing T3 is an example of the third value.

For example, as shown in the enlarged view described above in FIG. 4, the CPU 14c identifies the voltage V3 at the timing T3 in step S105 and the voltage V2 at the timing T2 in steps S102 to 104 in the selected Hall signal HU. The voltage V1 at the timing T1 is specified.

Then, the CPU 14c calculates a voltage difference (hereinafter referred to as a first difference Vd1) indicating a difference between the voltage V1 at the timing T1 and the voltage V2 at the timing T2 (hereinafter referred to as the first difference Vd1) (step S107), and the voltage V2 and the timing T3 at the timing T2. A voltage difference (hereinafter, referred to as a second difference Vd2) indicating a difference from the voltage V3 in the above is calculated (step S108).

For example, in the example of the above-mentioned enlarged view in FIG. 4, the CPU 14c calculates (V2-V1) as the first difference Vd1 in step S107, and in step S108, (V3-V2) is the second difference Vd2. Calculated as.

That is, the CPU 14c has the voltage V1 of the selected Hall signal (Hall signal HU, HV or HW) at the timing T1 of the edge of the signal 21 from the A phase or the signal 22 from the B phase, and the timing after the timing T1. The first difference Vd1 indicating the difference from the voltage V2 of the selected Hall signal at the timing T2, which is the timing of the edge of the signal 21 from the A phase or the signal 22 from the B phase, is calculated. Further, the CPU 14c is the difference between the voltage V2 and the voltage V3 of the selected Hall signal at the timing T3 which is the timing after the timing T2 and is the timing of the edge of the signal 21 from the A phase or the signal 22 from the B phase. The second difference Vd2 indicating the above is calculated.

Then, the CPU 14c calculates (Vd1 / α) by dividing the first difference Vd1 by a predetermined value α (step S109). The predetermined value α is a value indicating how many times the detection resolution of the rotation angle is to be multiplied, and is set by the user. For example, when the predetermined value α is “25”, the resolution of the rotation angle detected by the high resolution detection process is 25 times higher. If the calculated (Vd1 / α) value is smaller than 1, it means that the required resolution is not satisfied. Therefore, review the resolution or reexamine the performance of the A / D converter 14b. do it.

Then, the CPU 14c calculates how many times the second difference Vd2 is (Vd1 / α) (step S110). For example, the CPU 14c divides the second difference Vd2 by (Vd1 / α) to calculate (α · Vd2 / Vd1), so that the second difference Vd2 is a multiple of (Vd1 / α). Is calculated. That is, the second difference Vd2 is (α · Vd2 / Vd1) times (α · Vd2 / Vd1) times (Vd1 / α).

If (α ・ Vd2 / Vd1) does not become a natural number and includes a numerical value after the decimal point, the CPU 14c may use a value rounded to the first decimal place of (α ・ Vd2 / Vd1). .. In the following description, the value obtained by rounding off the first decimal place of (α ・ Vd2 / Vd1) is also referred to as (α ・ Vd2 / Vd1).

_{Then, the CPU 14c calculates the rotation angle θ T3} of the motor 10 (rotor 10a) at the timing T3 according to the following equation (1) (step S111), and ends the high resolution detection process.

θ _T3 = θ _T2 + θ _div × (α · Vd2 / Vd1) (1)

_{The θ T2} in the equation (1) will be described. θ _T2 is the rotation angle of the motor 10 (rotor 10a) at the timing T2. The CPU 14c calculates _{θ T2} by counting the pulses of the encoder signal.

_{Further, the term θ div} × (α · Vd2 / Vd1) in the equation (1) refers to the amount of change from the rotation angle of the motor 10 (rotor 10a) at the timing T2 to the rotation angle at the timing T3. _{The θ div} in the equation (1) is a rotation angle obtained by dividing the rotation angle (first rotation angle) corresponding to the first difference Vd1 by a predetermined value α, and is calculated in step S109 (Vd1 / α). The corresponding rotation angle. The rotation angle corresponding to the first difference Vd1 refers to the amount of change from the rotation angle of the motor 10 (rotor 10a) at the timing T1 to the rotation angle at the timing T2.

For example, when the encoder 11 has a resolution of 400 P / R and the predetermined value α is “25”, 0.036 (360 / (400 × 25)) degrees corresponds to (Vd1 / α). It is a rotation angle and is θ _div . In this case, as can be seen from the equation (1), the resolution of the detectable rotation angle is 0.036 degrees. On the other hand, when the encoder 11 has a resolution of 400 P / R, the resolution of the detectable rotation angle is 0.9 (360/400) degrees. Therefore, the resolution of the detectable rotation angle is increased 25 times from 0.9 degrees to 0.036 degrees. That is, according to the rotation detection device 15 and the motor device 1 according to the present embodiment, even if the encoder 11 itself has a resolution of 400 P / R, the rotation angle can be set at 25 times the resolution (10000 P / R) of 400 P / R. Can be detected.

From the above, the CPU 14c has a first voltage corresponding to the voltage at the timing T1 specified in steps S102 to 104, the voltage at the timing T2, the voltage at the timing T3 specified in the step S105, and the first difference Vd1. The rotation angle of the motor 10 (rotor 10a) at the timing T3 is detected based on the rotation angle of.

Further, the CPU 14c has a rotation angle of the motor 10 (rotor 10a) at the timing T3 based on the first difference Vd1, the second difference Vd2, and the first rotation angle corresponding to the first difference Vd1. Is detected.

Further, the CPU 14c uses the equation (1) to obtain a second difference Vd2 from a first rotation angle corresponding to the first difference Vd1 based on the ratio of the first difference Vd1 and the second difference Vd2. The second rotation angle θ _div × (α · Vd2 / Vd1) corresponding to the above is calculated. Then, the CPU 14c detects the sum of the calculated second rotation angle θ _div × (α · Vd2 / Vd1) and the rotation angle θ _T2 of the motor 10 (rotor 10a) at the timing T2 as the rotation angle at the timing T3. do.

From the above, according to the rotation detection device 15 and the motor device 1 according to the present embodiment, the rotation angle can be detected with high resolution without improving the encoder.

Further, since the rotation angle is detected by using the voltage (value) of the timing of the two edges closest to the timing T3, the rotation angle can be detected accurately without any error.

The rotation angle detected with high resolution is used for various controls. For example, when the motor device 1 controls to rotate and linearly move the ball screw by driving the motor 10 to rotate, the rotation angle can be detected with high resolution. Therefore, the ball screw can be used. It can be stopped with high accuracy at a predetermined position to be stopped.

Further, in the above-described embodiment, the case where high-resolution detection processing is performed using the Hall signals HU, HV, and HW from the magnetic sensors 12a, 12b, and 12c is illustrated, but the waveform changes with the rotation of the motor 10. Any signal may be used as long as it is a signal. For example, high-resolution detection processing may be performed using the signal of the back electromotive force of the motor 10.

Further, the CPU 14c rotates the motor 10 (rotor 10a) in the timing T3 according to the following equation (2) under the condition that the value of the first difference Vd1 can be large and the specified resolution is surely satisfied. The angle θ _T3 may be calculated.

θ _T3 = θ _T2 + θ _Vd1 × (Vd2 / Vd1) (2)

_{Here, θ Vd1} in the equation (2) is a first rotation angle corresponding to the first difference Vd1. From the viewpoint of calculating the rotation angle θ _T3 , the equation (1) and the equation (2) are substantially the same equation, but the equation (1) is an equation in consideration of the required resolution.

According to the equation (2), the CPU 14c is the motor 10 (at the timing T3) based on the first difference Vd1, the second difference Vd2, and the first rotation angle θ _{Vd1 corresponding to the first difference Vd1.} The rotation angle of the rotor 10a) is detected.

Further, the CPU 14c has a second difference from the _{first rotation angle θ Vd1} corresponding to the first difference Vd1 based on the ratio of the first difference Vd1 and the second difference Vd2 according to the equation (2). The second rotation angle θ _Vd1 × (Vd2 / Vd1) corresponding to Vd2 is calculated. Then, the CPU 14c detects the sum of the calculated second rotation angle θ _Vd1 × (Vd2 / Vd1) and the rotation angle θ _T2 of the motor 10 (rotor 10a) at the timing T2 as the rotation angle at the timing T3.

From the above, even when the equation (2) is used, the rotation detection device 15 and the motor device 1 according to the present embodiment detect the rotation angle with high resolution without improving the encoder. be able to.

Here, an example of a time axis element for the rotation detection device 15 according to the present embodiment will be described. For example, when the A / D converter 14b takes 1 μs to convert a Hall signal HU, HV, or HW of one channel, which is an analog signal, into a digital signal, and the conversion preparation time takes 2 μs. Including the conversion preparation time, it takes 3 μs to convert the Hall signal HU, HV or HW of one channel from an analog signal to a digital signal. Since the A / D converter 14b converts the Hall signals HU, HV, and HW of the three channels from analog signals to digital signals, the total conversion time of the A / D converter 14b is 9 μs (3 (μs) × 3). It takes time.

When the resolution is increased 25 times, it takes 9 (μs) × 25 × 400 (pulse) = 90 ms for the motor 10 (rotor 10a) to make one rotation. The processing limit rotation speed is (1000/90) × 60 = 666.7 min ^-1 . Therefore, it is considered that the rotation detection device 15 that operates under the various conditions described above ^{can be used at about 667 min-1.}

Further, an example of the amplitude axis element of the rotation detection device 15 according to the present embodiment will be described. The case where the full-scale voltage of the A / D converter 14b is 5000 mV, the full-scale data is 4095, and the above-mentioned first voltage difference Vd1 is 120 mV will be described. Here, for a plurality of edges of the signal 21 from the A phase and the edge of the signal 22 from the B phase, two temporally adjacent edges are set as one pulse. In this case, the voltage for one pulse is 120 mV. The data for one pulse is (120/5000) × 4095 = 98.28.

When the resolution is increased 25 times, the data value per resolution is 98.25 / 25 = 3.93. Therefore, an error margin of about 3 digits is expected.

The present invention is not limited to the above embodiments. The present invention also includes those configured by appropriately combining the above-mentioned constituent elements. Further, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

1 Motor device 10 Motor 10a Rotor 11 Encoder 12a, 12b, 12c Magnetic sensor 13a, 13b, 13c Operational amplifier (arithmetic amplifier)
14 Microcomputer 14a Counter 14b A / D converter 14c CPU (detector)
15 Rotation detector 16 Drive circuit

Claims (5)

An encoder for detecting the intermittent rotation angle of the rotation angle of the rotating body,
A first voltage signal corresponding to the rotation of the rotating body at the first timing rotational angle is detected by the pre-Symbol encoder, by the first of the encoder and a second timing later than the timing The second voltage of the signal corresponding to the rotation of the rotating body at the second timing when the rotation angle is detected, and the signal corresponding to the rotation of the rotating body at the third timing after the second timing. The third voltage, the first difference showing the difference between the first voltage and the second voltage, and the second difference showing the difference between the second voltage and the third voltage. A detection unit that detects the rotation angle of the rotating body at the third timing based on the first rotation angle corresponding to the first difference.
The detection unit selects the Hall signal having the largest absolute value of inclination at the third timing from the signals of the three-phase Hall element that outputs a signal corresponding to the rotation of the rotating body, and the first one. The value of the selected Hall signal at the timing is defined as the first voltage, the value of the selected Hall signal at the second timing is defined as the second voltage, and the value of the selected Hall signal at the third timing is defined as the second voltage. Using the value as the third voltage, the rotation angle of the rotating body at the third timing is detected.
Rotation detector. The detection unit calculates and calculates a second rotation angle corresponding to the second difference from the first rotation angle based on the ratio of the first difference to the second difference. The rotation detection device according to claim 1, wherein the sum of the second rotation angle and the rotation angle of the rotating body at the second timing is detected as the rotation angle at the third timing. In the detection unit, Vd2 is (Vd1 / α) when predetermined values indicating the magnification of the detection resolution of the first difference, the second difference, and the rotation angle of the rotating body are Vd1, Vd2, and α, respectively. ) Is (α × Vd2 / Vd1) times, the rotation angle of the rotating body at the third timing is detected.
The rotation detection device according to claim 1 or 2. The rotation detection device according to any one of claims 1 to 3.
A motor equipped with the rotating body as a rotor and
Motor equipment including. From the first voltage of the signal corresponding to the rotation of the rotating body at the first timing when the rotation angle is detected by the encoder that detects the intermittent rotation angle among the rotation angles of the rotating body, and the first timing. The second voltage of the signal at the second timing after the second timing and the rotation angle is detected by the encoder, and the signal at the third timing after the second timing. A third voltage, a first difference showing the difference between the first voltage and the second voltage, and a second difference showing the difference between the second voltage and the third voltage. A step of detecting the rotation angle of the rotating body at the third timing based on the first rotation angle corresponding to the first difference is included.
In the step, among the signals of the three-phase Hall element that outputs a signal corresponding to the rotation of the rotating body, the Hall signal having the largest absolute value of inclination at the third timing is selected, and the first timing is described. The value of the selected Hall signal in the above is the first voltage, the value of the selected Hall signal at the second timing is the second voltage, and the value of the selected Hall signal at the third timing. Is the third voltage, and the rotation angle of the rotating body at the third timing is detected.
Rotation detection method.

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