JP2012196029A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to supplement the number of pulses of a ripple component that is not extracted when an extraction circuit such as a switched capacitor filter does nor correctly extract the ripple component due to variations and the like in the power source voltage of a motor.SOLUTION: A motor controller 1 includes: a motor 2; an extraction circuit for converting the ripple component of the current signal of the motor 2 into a pulse signal; an A/D converter 7 for detecting the voltage of the motor 2; and a controller 4 for inputting a pulse signal. When the controller 4 detects a variation of voltage detected by the A/D converter 7, the controller 4 calculates an average period T_average of a pulse period T_before for one pulse or a plurality of pulses just before the voltage variation and a pulse period T_after for one pulse or a plurality of pulses after passing a predetermined period t from the voltage variation and calculates a quotient n obtained by dividing the predetermined period t by the average period T_average.

Description

  The present invention relates to a motor control device.

  A movable part is provided in a vehicle seat, an electric door mirror, a power window, and the like, and the movable part is driven by a motor. In order to accurately control the position and speed of the movable part by the control device, it is necessary to detect the rotation amount of the motor in operation. A sensor is used to detect the rotation amount of the motor. That is, a sensor (for example, a hall element, an encoder, a reed switch sensor) is provided in a motor or the like, a signal synchronized with the rotation of the motor in operation is output by the sensor, and the output signal of the sensor is detected by a detection circuit (for example, a comparator or It is input to the control device via the AD converter.

  However, using a sensor increases the cost. Therefore, a technique has been proposed in which the motor rotation amount is detected by a circuit subsequent to the motor using a motor current signal without using a sensor (see, for example, Patent Document 1 and Patent Document 2). When the motor is operating, the current signal of the motor includes a direct current component, a low frequency component, a high frequency noise, and the like, and further, a pulsation synchronized with the rotation of the motor (hereinafter referred to as ripple). ) Ingredients are also included. In the techniques described in Patent Document 1 and Patent Document 2, a ripple component is extracted by processing a current signal of a motor by a subsequent circuit. Specifically, a DC component, a low frequency component, and a high frequency noise are removed from the motor current signal by a filter in the subsequent circuit, and the ripple component is passed. Since the frequency of each component of the motor current signal fluctuates due to environmental changes, a switched capacitor filter capable of varying the cut-off frequency is used as the filter of the subsequent circuit. Specifically, a signal that has passed through the switched capacitor filter is fed back to the arithmetic circuit, and the arithmetic circuit calculates a cutoff frequency from the feedback signal to set the cutoff frequency of the switched capacitor filter.

  In the technique described in Patent Document 1, the ripple pulse shaping circuit pulses the ripple component that has passed through the switched capacitor filter (SCF), and the counter (CT) counts the number of pulses of the output signal of the ripple pulse shaping circuit. . The number of pulses counted by the counter (CT) corresponds to the amount of rotation of the motor and the amount of movement of the movable part.

Japanese Patent Laid-Open No. 2003-9585 JP 2008-283762 A

In the conventional technology, the cutoff frequency of the switched capacitor filter is set by feedback control. Therefore, if the frequency of each component of the motor current signal changes transiently or rapidly, the setting of the cutoff frequency is delayed. Therefore, the ripple component may not be accurately extracted even by the switched capacitor filter.
In particular, when the motor power supply voltage fluctuates due to various external factors, the motor current value also fluctuates, so that the amplitude of the ripple component included in the motor current signal decreases when the motor current value fluctuates. Therefore, the ripple component is not accurately extracted by the switched capacitor filter in the subsequent stage. Therefore, the counter can accurately count the number of pulses, and the rotation amount of the motor and the movement amount of the movable part are not accurately measured.
Therefore, the problem to be solved by the present invention is extracted even if the extraction circuit such as the switched capacitor filter does not accurately extract the ripple component due to the fluctuation of the power supply voltage of the motor. It is to be able to supplement the number of pulses of the ripple component that did not exist.

According to the invention according to claim 1 for solving the above problems,
The motor control device
A motor that generates a periodic ripple in the current signal when driven;
An extraction circuit that extracts a ripple component from the current signal of the motor and outputs a pulse signal obtained by pulsing the ripple component;
A voltage detector for detecting the voltage of the motor;
A controller that inputs the pulse signal and controls the motor;
The control unit is
A first process for counting the number of pulses of the pulse signal;
A second process of measuring the pulse period of the pulse signal for each pulse of the pulse signal and sequentially storing the measured pulse period;
In the case where a change in voltage detected by the voltage detector is detected, one pulse or a plurality of pulses immediately before detecting a change in voltage detected by the voltage detector in the pulse period stored in the second process Among the pulse period for the pulse and the pulse period stored in the second process, the pulse period for one pulse or a plurality of pulses after a predetermined period has elapsed since the detection of the voltage variation detected by the voltage detection unit A third process for calculating an average period with
And a fourth process for calculating a quotient obtained by dividing the predetermined period by the average period calculated in the third process.

According to the invention of claim 2, in claim 1,
The control unit is
A fifth process of counting the number of pulses of the pulse signal during the predetermined period when detecting a variation in the voltage detected by the voltage detector;
A sixth process of subtracting the number of pulses counted in the fifth process from the number of pulses counted in the first process and adding the quotient calculated in the fourth process is further executed.

According to the invention of claim 3, in claim 2,
The control unit further executes a seventh process of updating the number of pulses counted in the first process to a value obtained by addition and subtraction of the sixth process.

According to the invention of claim 4,
The motor control device
A motor that generates a periodic ripple in the current signal when driven;
An extraction circuit that extracts a ripple component from the current signal of the motor and outputs a pulse signal obtained by pulsing the ripple component;
A voltage detector for detecting the voltage of the motor;
A controller that inputs the pulse signal and controls the motor;
The control unit is
A first process for calculating the amount of rotation of the motor by counting the number of pulses of the pulse signal;
A second process of calculating the rotational speed of the motor for each pulse of the pulse signal by measuring the pulse period of the pulse signal for each pulse of the pulse signal and sequentially storing the calculated rotational speed for each pulse; ,
When a voltage variation detected by the voltage detector is detected, out of the rotation speed stored in the second process, one pulse or a plurality of pulses immediately before detecting the voltage variation detected by the voltage detector The rotation speed for one pulse or a plurality of pulses after a predetermined period of time has elapsed after detecting the fluctuation of the voltage detected by the voltage detection unit among the rotation speed for the pulse and the pulse period stored in the second process A third process for calculating an average rotation speed with
And a fourth process for calculating a product obtained by multiplying the predetermined period by the average rotation speed calculated in the third process.

According to the invention of claim 5, in claim 4,
The control unit is
A fifth method for calculating the amount of rotation of the motor during the predetermined period by counting the number of pulses of the pulse signal during the predetermined period when a change in the voltage detected by the voltage detection unit is detected. Processing,
A sixth process of subtracting the rotation amount calculated in the fifth process from the rotation amount calculated in the first process and adding the product calculated in the fourth process is further executed.

According to the invention of claim 6, in claim 5,
The control unit further executes a seventh process of updating the rotation amount calculated in the first process to a value obtained by addition and subtraction of the sixth process.

According to the first aspect of the present invention, even when the extraction circuit cannot accurately extract the pulse component during the predetermined period during which the power supply voltage of the motor will fluctuate, the control unit immediately before and after the predetermined period. The quotient is calculated by dividing the predetermined period by the average value of the pulse periods. The quotient represents the number of pulses in the predetermined period when the extraction circuit can extract the pulse component. Therefore, the number of pulses counted in the first process is supplemented by the number of pulses of the ripple component that has not been extracted. Therefore, an accurate pulse number is obtained.
Further, since the extraction circuit is not a closed loop circuit such as a feedback control circuit, even if the frequency of each component of the motor current signal changes transiently or rapidly, the ripple component is accurately extracted by the extraction circuit.

According to the fourth aspect of the present invention, even when the extraction circuit cannot accurately extract the pulse component during the predetermined period during which the power supply voltage of the motor will fluctuate, the control unit immediately before and after the predetermined period. The product is calculated by multiplying the average value of the rotation speeds by the predetermined period. The product represents the rotation amount of the motor in the predetermined period when the extraction circuit can extract the pulse component. Therefore, the rotation amount calculated in the first process is supplemented by the rotation amount based on the number of pulses of the ripple component that has not been extracted. Therefore, the rotation amount of the motor is accurately calculated.
Further, since the extraction circuit is not a closed loop circuit such as a feedback control circuit, the ripple component is accurately extracted by the extraction circuit.

It is the block diagram which showed the motor control apparatus which concerns on embodiment to which this invention is applied. It is a timing chart showing a waveform of a motor current signal. It is a timing chart showing a waveform of a motor current signal. It is the figure which showed the waveform of the input signal and output signal of a current-voltage converter, a high pass filter, a band pass filter, a filter and a differential amplifier, an amplifier, and a waveform shaping part. It is the graph which showed the frequency characteristic of the filter. It is a circuit diagram showing a filter and a differential amplifier. It is the timing chart which showed the waveform of the input signal and output signal of a filter and a differential amplifier. It is the flowchart which showed the flow of the process which starts a motor. It is the flowchart which showed the flow of the process which counts the pulse number of a pulse signal during operation | movement of a motor. 5 is a timing chart showing waveforms of a power supply voltage, a motor current signal, and a pulse signal when the motor power supply voltage fluctuates during operation of the motor. It is the flowchart which showed the flow of the process which time-measures the pulse period of a pulse signal during operation | movement of a motor. It is the flowchart which showed the flow of the process which counts the pulse number of the pulse signal during the predetermined estimation period when the power supply voltage of a motor fluctuates. It is the flowchart which showed the flow of the process which calculates the estimated number of pulses of the pulse signal during a predetermined estimation period when the power supply voltage of the motor fluctuates. It is the flowchart which showed the flow of the process which correct | amends the pulse number counted during operation | movement of a motor. It is the side view which showed the sheet | seat main body of the vehicle seat. It is the graph which showed the frequency characteristic of the filter. It is the graph which showed the frequency characteristic of the filter.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

FIG. 1 is a block diagram of the motor control device 1.
The motor control device 1 includes a motor 2, an extraction circuit 3, a control unit 4, a storage unit 5, a motor driver 6, an A / D converter 7, and the like.

  The motor 2 is a direct current motor. When a current flows through the motor 2, the motor 2 rotates and the motor 2 generates a periodic ripple in the current. The current signal of the motor 2 will be described with reference to FIGS. FIG. 2 is a chart showing changes in the level of current flowing through the motor 2 when the motor 2 is driven. FIG. 3 is a chart showing an enlarged scale of time and current in part A shown in FIG.

In FIG. 2, time T1 is timing when the motor 2 is started, and time T2 is timing when the motor 2 starts to operate stably. Time T3 is a timing when the movable part driven by the motor 2 comes into contact with a stopper or the like and the transmission mechanism that transmits the power of the motor 2 to the movable part starts to be restrained. Time T4 is timing when the motor 2 stops.
As shown in FIGS. 2 and 3, the current signal of the motor 2 includes a DC component, a ripple component, and one or more frequency components (AC component), and the frequency component and the ripple component are superimposed on the DC component. Of the current signal of the motor 2, the high frequency component in which the current level has changed abruptly is noise (see, for example, symbol n). Note that FIG. 3 is illustrated as having no high frequency noise component.

In a period P1 from time T1 to time T2, the ripple component r1 and a low frequency component having a frequency lower than the ripple component r1 are superimposed on the direct current component. Immediately after the start of the motor 2 in the period P1, the current level of the low frequency component is large due to the influence of the inertial force, and then the current level of the low frequency component gradually decreases with time. Immediately after the start of the motor 2, the amplitude of the ripple component r1 having a higher frequency than the low frequency component is large, and thereafter, the frequency of the ripple component r1 gradually increases with time, and the amplitude of the ripple component r1 is increased over time. It gradually decreases with the progress of.
In the period P2 from time T2 to time T3, the ripple component r2 and the low frequency component having a frequency lower than the ripple component r2 are superimposed on the DC component, the DC component is substantially constant and stable, and the frequency of the low frequency component and The amplitude is stable, and the frequency and amplitude of the ripple component r2 are stable. The reason why the frequency of the ripple component r2 is higher than the frequency of the low frequency component is that a plurality of coils built in the motor 2 have a difference in winding resistance.
In a period P3 from time T3 to time T4, the frequency of the low frequency component of the motor current signal is lowered, and the current level of the low frequency component gradually increases with time. In the period P3, the frequency of the ripple component r3 of the motor current signal gradually decreases with the passage of time, and the amplitude of the ripple component r3 gradually increases with the passage of time.

  The frequency and amplitude of the low frequency component and the ripple component of the current signal of the motor 2 are affected by various environments (for example, load on the motor 2, environmental temperature, power supply voltage of the motor 2, etc.). Therefore, when the environment changes, the frequency and amplitude of the low frequency component and the ripple component change.

  The extraction circuit 3 extracts a ripple component from the current signal of the motor 2 as described above, pulses the ripple component, and outputs a pulse signal obtained by pulsing the ripple component to the control unit 4. The ripple extraction method using the extraction circuit 3 and the extraction circuit 3 will be specifically described.

  As shown in FIG. 1, the extraction circuit 3 includes a current-voltage converter 10, a high-pass filter 20, a band-pass filter 30, a filter 40, a differential amplifier 50, an amplifier 60, and A waveform shaping unit 70 is provided. FIG. 4 is a diagram for explaining input signals and output signals of the current-voltage converter 10, the high-pass filter 20, the band-pass filter 30, the filter 40 and the differential amplifier 50, the amplifier 60, and the waveform shaping unit 70. In FIG. 4, the period in which the input signal and the output signal of the current-voltage converter 10, the high-pass filter 20, and the band-pass filter 30 are shown is from the time T1 to the beginning of the period P2 in FIG. A period in which the input signals and output signals of the filter 40, the differential amplifier 50, the amplifier 60, and the waveform shaping unit 70 are shown is a part of the period P2 in FIG.

  The current / voltage converter 10 inputs a current signal of the motor 2. The current-voltage converter 10 converts the input current signal of the motor 2 into a voltage signal. Specifically, the current-voltage converter 10 includes a resistor 11, the resistor 11 is connected between the ground and the motor 2, and the current signal of the motor 2 is converted into a voltage signal between the resistor 11 and the motor 2. Converted. The current-voltage converter 10 outputs the converted voltage signal to the filter 40 and the differential amplifier 50 via the high-pass filter 20 and the band-pass filter 30. The current-voltage converter 10 may be one using an operational amplifier (for example, a negative feedback current-voltage converter).

The high-pass filter 20 receives the voltage signal converted by the current-voltage converter 10 (output signal of the current-voltage converter 10). The high-pass filter 20 passes a high-frequency component of the voltage signal converted by the current-voltage converter 10 (an output signal of the current-voltage converter 10) and attenuates a low-frequency component. That is, the high pass filter 20 removes a DC component from the voltage signal converted by the current-voltage converter 10. The high pass filter 20 outputs a signal with the low frequency component attenuated to the filter 40 and the differential amplifier 50 via the band pass filter 30.
The high-pass filter 20 is one using an operational amplifier (for example, a negative feedback high-pass filter or a positive feedback high-pass filter) or one using a resistor / capacitor (for example, a CR high-pass filter).

The bandpass filter 30 inputs the voltage signal converted by the current-voltage converter 10 via the highpass filter 20. The band-pass filter 30 passes a component in a predetermined frequency band of the voltage signal (the output signal of the high-pass filter 20) converted by the current-voltage converter 10, and attenuates a component outside the predetermined frequency band. That is, the band-pass filter 30 removes high-frequency noise components from the voltage signal (output signal of the high-pass filter 20) converted by the current-voltage converter 10, and removes low-frequency components that could not be removed by the high-pass filter 20. Remove. The bandpass filter 30 outputs a signal obtained by attenuating a component outside a predetermined frequency band to the filter 40 and the differential amplifier 50.
The band pass filter 30 uses an operational amplifier (for example, a multiple negative feedback type band pass filter, a multiple positive feedback type band pass filter) or a resistor / capacitor.

  The filter 40 receives the voltage signal converted by the current-voltage converter 10 through the high-pass filter 20 and the band-pass filter 30, and filters the signal. The filter 40 outputs the filtered signal to the differential amplifier 50.

FIG. 5 is a graph showing the frequency characteristics of the filter 40.
As shown in FIG. 5, the filter 40 is a band pass filter. The filter 40 passes the component in the intermediate frequency band between the low cutoff frequency fc1 and the high cutoff frequency fc2 in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10. . Low cut-off frequency fc1 <high cut-off frequency fc2. The cut-off frequency refers to a frequency at which the output power is 1/2 of the input power. That is, the frequency at which the gain G is −3 db is the cutoff frequency.
Further, the filter 40 attenuates a component in a low frequency range lower than the low cutoff frequency fc1 in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10. Specifically, in the low frequency range lower than the low cut-off frequency fc1, the filter 40 has a lower component frequency included in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10. The low frequency band component of the voltage signal (the output signal of the band pass filter 30) converted by the current-voltage converter 10 is attenuated so that the attenuation rate becomes higher.
Further, the filter 40 attenuates a component in a high frequency region exceeding the high cut-off frequency fc2 in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10. Specifically, in a high frequency region exceeding the high cut-off frequency fc2, the filter 40 attenuates as the frequency of the component included in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 decreases. The high frequency component of the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 is attenuated so that the rate becomes lower.

  As shown in FIGS. 2 and 3, the current signal of the motor 2 is obtained by superimposing a ripple component and a low frequency component having a frequency lower than that of the ripple component. The frequency of the ripple component is checked in advance by experiments, measurements, etc., and in the circuit design of the filter 40, the high cutoff frequency fc2 of the filter 40 is set to the frequency of the ripple component (for example, the frequency of the ripple component due to temperature change). , The frequency at room temperature). Therefore, the filter 40 has a ripple component in the voltage signal (the output signal of the band pass filter 30) converted by the current-voltage converter 10 that is lower in frequency than the low frequency component (the frequency of the low frequency component is lower than that of the ripple component). Attenuate with high attenuation factor. That is, the filter 40 removes the ripple component more efficiently than the low frequency component. Therefore, the filter 40 outputs a signal from which the ripple component has been removed to the differential amplifier 50.

  The differential amplifier 50 inputs the voltage signal converted by the current-voltage converter 10 via the high-pass filter 20 and the band-pass filter 30 and also receives the output signal of the filter 40. The differential amplifier 50 takes the difference between the input output signal of the filter 40 and the voltage signal converted by the current-voltage converter 10 (the output signal of the bandpass filter 30), and amplifies the difference. The differential amplifier 50 outputs a differential signal representing the difference to the amplifier 60.

  FIG. 6 is a circuit diagram illustrating an example of the filter 40 and the differential amplifier 50. FIG. 7A is a timing chart showing the waveform of the voltage signal in the A section shown in FIG. 6, and FIG. 7B is a timing showing the waveform of the voltage signal in the B section shown in FIG. FIG. 7C is a timing chart showing the waveform of the voltage signal in the portion C shown in FIG.

  As shown in FIG. 6, the filter 40 includes a high pass filter 41, a low pass filter 42, and a high pass filter 43. The output of the band pass filter 30 is connected to the input of the high pass filter 41, the output of the high pass filter 41 is connected to the input of the low pass filter 42, and the output of the low pass filter 42 is connected to the output of the high pass filter 43.

The high pass filter 41 is a secondary CR high pass filter. That is, the high pass filter 41 includes a capacitor 41a, a resistor 41b, a capacitor 41c, and a resistor 41d. Note that the high-pass filter 41 may be a primary CR high-pass filter including one capacitor and a resistor. Further, the high-pass filter 41 may be a third-order or higher CR high-pass filter.
The low pass filter 42 is a secondary RC low pass filter. That is, the low-pass filter 42 includes a resistor 42a, a capacitor 42b, a resistor 42c, and a capacitor 42d. The low-pass filter 42 may be a primary RC low-pass filter including one resistor and a capacitor. Further, the low-pass filter 42 may be a third-order or higher RC low-pass filter.
The high pass filter 43 includes a capacitor 43a.

  The differential amplifier 50 includes resistors 51 and 52, an operational amplifier 53, a coupling capacitor 54, a bias circuit 55, and the like. The output terminal of the operational amplifier 53 is connected to the inverting input terminal of the operational amplifier 53 via the resistor 52, and negative feedback is applied to the operational amplifier 53. The output signal of the filter 40 (the output signal of the high pass filter 43) is input to the inverting input terminal of the operational amplifier 53 via the resistor 51, and the output signal of the band pass filter 30 is supplied to the operational amplifier via the coupling capacitor 54 and the bias circuit 55. 53 is input to the non-inverting input terminal. The coupling capacitor 54 removes a direct current component of the output signal of the band pass filter 30. The bias circuit 55 includes resistors 56 and 57 connected in series between the power supply voltage and the ground. The bias circuit 55 applies a bias voltage to the output signal of the bandpass filter 30 from which the DC component has been removed by the coupling capacitor 54, and raises the reference level of the output signal of the bandpass filter 30. Note that the coupling capacitor 54 and the bias circuit 55 may be omitted.

  The differential signal output by the differential amplifier 50 is a ripple component of the voltage signal converted by the current-voltage converter 10. Because the difference signal output by the differential amplifier 50 represents the difference between the output signal of the bandpass filter 30 and the output signal of the filter 40, the frequency of each component of the current signal of the motor 2 changes due to environmental changes. In addition, ripples included in the current signal of the motor 2 can be detected with high accuracy.

  As shown in FIGS. 1 and 6, the amplifier 60 receives the differential signal (the output signal of the operational amplifier 53) output by the differential amplifier 50. The amplifier 60 amplifies the differential signal output by the differential amplifier 50 and outputs it to the waveform shaping unit 70. The amplifier 60 is, for example, a negative feedback amplifier.

  The waveform shaping unit 70 inputs the differential signal (the output signal of the operational amplifier 53) output from the differential amplifier 50 via the amplifier 60. The waveform shaping unit 70 shapes the waveform of the differential signal (the output signal of the amplifier 60) output by the differential amplifier 50 into a rectangular wave. Specifically, the waveform shaping unit 70 has a comparator, and the comparator compares the differential signal (the output signal of the amplifier 60) output by the differential amplifier 50 with a reference voltage, thereby allowing the differential amplifier 50 to The output differential signal (the output signal of the amplifier 60) is converted into a pulse signal. The waveform shaping unit 70 outputs a pulse signal shaped into a rectangular wave to the control unit 4. The control unit 4 receives the pulse signal output from the waveform shaping unit 70.

  The motor driver 6 drives the motor 2 in accordance with a command from the control unit 4. That is, when the motor driver 6 receives the start command and the rotation direction command from the control unit 4, the motor driver 6 starts the motor 2 in the rotation direction. The motor driver 6 drives the motor 2 at the set speed according to the set speed command received from the control unit 4. When the motor driver 6 receives a stop command from the control unit 4, the motor driver 6 stops the motor 2.

  The A / D converter 7 is a voltage detection unit. That is, the A / D converter 7 detects the power supply voltage of the motor 2, converts the voltage signal into a digital signal, and outputs the digitized voltage data to the control unit 4. The control unit 4 inputs voltage data output by the A / D converter 7.

  The control unit 4 is a computer having a CPU 4a, a RAM 4b, and the like. The CPU 4a performs various processes such as numerical calculation, information processing, and device control. The RAM 4b provides a work area as a temporary storage area to the CPU 4a.

  The storage unit 5 is connected to the control unit 4. The storage unit 5 is a readable / writable storage medium such as a nonvolatile memory or a hard disk. The storage unit 5 may be a single storage medium or a combination of a plurality of storage media.

  The storage unit 5 stores initial position data 5A. The initial position data 5A indicates the initial rotational position of the motor 2 before the motor 2 operates and the initial position of the movable part driven by the motor 2. Specifically, the initial position data 5A is the number of pulses of a pulse signal when the motor 2 rotates from a predetermined origin position to an initial rotation position. A value obtained by multiplying the number of pulses by a predetermined constant is a rotation amount when the motor 2 rotates from a predetermined origin position to an initial rotation position, and is an initial value of the motor 2 before the motor 2 operates. Indicates the rotational position. The initial position data 5A is a preset default value or a value written when the motor 2 has been operated before. If the initial rotational position of the motor 2 is the origin position, the initial position data 5A is zero.

  The storage unit 5 stores a program 5Z that can be read by the control unit 4. The control unit 4 reads the program 5Z and performs processing according to the program 5Z, or implements various functions by the program 5Z. When the storage unit 5 is a combination of a plurality of storage media, the program 5Z may be stored in the ROM of the storage unit 5.

  The control unit 4 functions as means described below by the program 5Z.

The control unit 4 functions as a starting unit that outputs a command and a start command regarding the rotation direction to the motor driver 6 to start the motor 2.
The control unit 4 functions as a counting unit that counts the number of pulses of the output signal of the waveform shaping unit 70. A value obtained by multiplying the number of pulses counted by the counting means by a predetermined constant corresponds to the amount of rotation of the motor 2 and also corresponds to the amount of movement of the movable part driven by the motor 2. Therefore, the counting means is also a movement amount calculation means for calculating the rotation amount of the motor 2 and the movement amount of the movable part driven by the motor 2.
The control unit 4 functions as a time measuring unit that measures the pulse period of the output signal of the waveform shaping unit 70 (the time from the rising edge of the pulse to the rising edge of the next pulse) for each pulse. A value obtained by multiplying the reciprocal of the pulse period measured by the control unit 4 by a predetermined constant corresponds to the rotation speed of the motor 2 and to the speed of the movable part driven by the motor 2. Therefore, the time measuring means is also a speed calculating means for calculating the rotational speed of the motor 2 and the moving speed of the movable part driven by the motor 2.
The control unit 4 functions as an accumulating unit that sequentially stores the pulse period of each pulse measured by the time measuring unit.
The control unit 4 functions as a monitoring unit that monitors the voltage data input from the A / D converter 7.
The control unit 4 functions as a second timing unit that starts timing when the voltage data monitored by the monitoring unit is detected and continues the timing until the measured time reaches a predetermined estimated time t. .
The control unit 4 functions as a second counting unit that counts the number of pulses of the output signal of the waveform shaping unit 70, separately from the counting by the counting unit, while the timing unit performs timing.
The control unit 4 includes a pulse period T_before for one pulse or a plurality of pulses immediately before detecting a change in the voltage data monitored by the monitoring unit among the pulse cycles sequentially stored by the storage unit, and a second timing unit. It functions as an average period calculating means for calculating an average period T_average with a pulse period T_after for one pulse or a plurality of pulses immediately after counting to the estimated time t.
The control unit 4 functions as an estimated pulse number calculation unit that calculates the estimated pulse number as the quotient by dividing the estimated time t by the average period T_average calculated by the average cycle calculation unit.
The control unit 4 functions as a correcting unit that subtracts the number of pulses counted by the second counting unit from the number of pulses counted by the counting unit and adds the estimated number of pulses calculated by the estimated number of pulses calculating unit.
The control unit 4 functions as an updating unit that updates the number of pulses counted by the counting unit to a value calculated by addition / calculation of the calculation unit.
The control unit 4 functions as a stopping unit that issues a stop command to the motor driver 6 to stop the motor 2.

  The flow of processing of the control unit 4 based on the program 5Z will be described, and the operation of the motor control device 1 accompanying the processing of the control unit 4 will be described.

  When a predetermined condition is satisfied, the control unit 4 executes a startup process of the motor 2 (see FIG. 8). The predetermined condition is satisfied when, for example, the user turns on the activation switch, the activation sensor is turned on, or the process (for example, sequence process) executed by the control unit 4 satisfies the predetermined condition. Etc.

  First, the control unit 4 determines the rotation direction (forward rotation or reverse rotation) of the motor 2, and writes the rotation direction in the RAM or the storage unit 5 (step S11).

  Next, the control part 4 starts the motor 2 in the direction determined in step S11 (step S12). That is, the control unit 4 outputs a rotation direction command according to the direction determined in step S <b> 11 to the motor driver 6 and outputs a start command to the motor driver 6. Thereby, the motor 2 is started and the movable part is driven by the motor 2. Thus, the startup process of the motor 2 is completed.

  During operation of the motor 2, the extraction circuit 3 extracts (detects) a ripple component from the current signal of the motor 2, and pulses the ripple component. Then, the extraction circuit 3 outputs a pulse signal obtained by pulsing the ripple component to the control unit 4.

  When the motor 2 is activated, the control unit 4 counts the number of pulses of the pulse signal, calculates the rotation amount of the motor 2, and calculates the rotation position of the motor 2 based on the pulse signal input from the extraction circuit 3. More specifically, the control unit 4 performs the processing shown in FIG. 9 to count the number of pulses of the pulse signal, calculate the rotation amount of the motor 2, and calculate the rotation position of the motor 2.

The process shown in FIG. 9 will be specifically described.
The control unit 4 monitors the voltage data input from the A / D converter 7 and compares the voltage data with a predetermined threshold value (step S21). As described above, when the control unit 4 activates the motor 2 (step S13), the current is supplied to the motor 2. Therefore, the control unit 4 determines that the voltage data exceeds a predetermined threshold value, Activation is detected (step S21: Yes). And the control part 4 reads the initial position data 5A from the memory | storage part 5, and the process of the control part 4 transfers to step S22.

  When the current is supplied to the motor 2, the control unit 4 counts the number of pulses of the pulse signal output by the extraction circuit 3, and calculates the rotation amount and rotation position of the motor 2 (steps S22, S23, S24, S25). . Specifically, first, the control unit 4 resets the count value N to zero (step S22). Thereafter, each time the pulse of the pulse signal output by the extraction circuit 3 is input (step S23: Yes), the controller 4 updates the count value N by adding 1 to the count value N (step S24). ) The updated count value N is added to the read initial position data 5A, or the updated count value N is subtracted from the read initial position data 5A (step S25). The control unit 4 determines the calculation in step S25 according to the direction determined in step S11. For example, when the rotation direction determined in step S11 is forward rotation, the control unit 4 performs addition in step S25, and when the rotation direction determined in step S11 is reverse rotation, the control unit 4 Subtracts in step S25. Of course, the relationship between the direction of rotation and the calculation may be reversed.

  The count value N updated in step S24 is the number of pulses counted by the control unit 4. Since the value obtained by multiplying the number of pulses (count value N) counted by the control unit 4 by a predetermined constant corresponds to the amount of rotation of the motor 2 or the amount of movement of the movable unit, the control unit 4 determines the number of pulses (count value). The process of counting N) (steps S21 to S26) corresponds to a process in which the control unit 4 calculates the rotation amount of the motor 2 and the movement amount of the movable unit. Further, the difference or sum obtained in step S25 indicates the rotational position of the motor 2 and the distance from the origin position with reference to the origin position.

  The control part 4 repeats the process of step S23-step S26 until it detects the interruption | blocking of the electric current of the motor 2 (step S26: No). That is, the control unit 4 compares the voltage data input from the A / D converter 7 with a predetermined threshold after the process of step S25 (step S26). If the voltage data exceeds the predetermined threshold (step S26: No), the process of the control unit 4 returns to step S23, and the control unit 4 performs the process of steps S23 to S25 again. On the other hand, when the voltage data is below the predetermined threshold (step S26: yes), the control unit 4 ends the process shown in FIG.

  If a predetermined condition is satisfied when the control unit 4 is executing the processing shown in FIG. 9, the control unit 4 outputs a stop command to the motor driver 6 to stop the motor 2. The predetermined condition is, for example, that the user turns on the stop switch, that the predetermined condition is satisfied by the process executed by the control unit 4 (for example, the sequence process), the difference obtained in step S25 described above, The sum is a predetermined value.

  When the control unit 4 stops the motor 2, the current of the motor 2 is cut off. Therefore, as shown in FIG. 9, the control unit 4 detects the cut-off of the current of the motor 2 (step S26: Yes), and the control unit 4 finishes the process shown in FIG. And the control part 4 writes the difference or sum calculated | required in the last step S25 in the memory | storage part 5 when repeating the process of step S23-step S26 shown in FIG. Specifically, the control unit 4 rewrites the initial position data 5A stored in the storage unit 5 with the sum or difference obtained in step S25.

  When various external factors (for example, cranking at the time of engine start of a vehicle equipped with the motor 2) occur during the operation of the motor 2, the power supply voltage of the motor 2 fluctuates rapidly as shown in FIG. When the power supply voltage of the motor 2 changes rapidly, the current value of the motor 2 also changes rapidly. When the current value of the motor 2 fluctuates rapidly, the amplitude of the ripple component included in the current signal is reduced, so that the extraction circuit 3 cannot extract the ripple component. In the period in which the amplitude of the ripple component is reduced, the pulse period of the pulse signal output by the extraction circuit 3 is extended, and the number of pulses in that period is reduced. Therefore, the control unit 4 complements the number of pulses during the period in which the power supply voltage of the motor 2 is rapidly changing by performing the following processing (see FIGS. 11 to 14).

  During the operation of the motor 2, the control unit 4 calculates the pulse period of the pulse signal. Specifically, the control unit 4 sequentially calculates the pulse period from the rising edge of the pulse to the rising edge of the next pulse by executing the process shown in FIG. The data is stored in the storage unit 5 sequentially.

  First, the control unit 4 resets the timekeeping time to zero (step S31). Next, the control unit 4 starts measuring time and continues measuring time until the pulse of the output pulse signal of the extraction circuit 3 rises (step S32, step S33: No). When the control unit 4 detects the rise of the pulse of the output pulse signal of the extraction circuit 3 (step S33: Yes), the control unit 4 ends the time measurement (step S34), and the time measured is stored in the RAM or the storage unit 5 or These are stored in both of them (step S35). And the control part 4 resets time-measurement time to zero again (step S31). When the control unit 4 repeats the processes of steps S31 to S35, the time measurement is sequentially stored in the RAM, the storage unit 5, or both. The time measured written in the RAM or the storage unit 5 or both is the pulse period of the output pulse signal of the extraction circuit 3. The reciprocal of the pulse period indicates the rotational speed of the motor 2 and the speed of the movable part driven by the motor 2. Therefore, the process in which the control unit 4 measures the pulse period for each pulse (steps S31 to S35) corresponds to a process for obtaining the rotation speed of the motor 2 and the speed of the movable part for each pulse.

  As shown in FIG. 10, when the power supply voltage of the motor 2 rapidly changes during the operation of the motor 2, the control unit 4 counts the number of pulses of the pulse signal during the change of the power supply voltage of the motor 2. Specifically, when the power supply voltage of the motor 2 fluctuates rapidly, the control unit 4 counts the number of pulses by executing a process as shown in FIG.

  The control unit 4 monitors the voltage data input from the A / D converter 7 and compares the voltage data with a predetermined threshold value (step S41). When the power supply voltage of the motor 2 changes rapidly, the voltage data falls below the threshold value, so the control unit 4 detects that the voltage data falls below the threshold value (step S41: Yes).

  Next, the control part 4 sets the estimation period t (step S42). The estimation period t is a preset period and is programmed in the program 5Z. The estimation period t indicates a period during which the power supply voltage of the motor 2 varies. For example, the estimation period t is previously investigated by experiments or the like. A look-up table or function representing the relationship between the voltage fluctuation range and time is stored in the storage unit 5 in advance, and the control unit 4 detects the voltage fluctuation range based on the voltage data of the A / D converter 7. The estimated period t may be obtained by applying the detected voltage fluctuation range to a lookup table or function.

Next, the control part 4 resets the count value M to zero (step S43).
Further, the control unit 4 resets the counting time to zero simultaneously with the reset of the count value M and starts counting (step S44), and continues counting until the counting time reaches the estimation period t (step S47: No). ). In addition, the control part 4 performs the time measurement in the process shown in FIG. 12 in parallel with the time measurement of the pulse period in the process shown in FIG.

  The control unit 4 updates the count value M by adding 1 to the count value M every time the pulse of the pulse signal output by the extraction circuit 3 is input during the timing (step S45: Yes) (step S45). S46). The control unit 4 counts the count value M in the process shown in FIG. 12 in parallel with the pulse number (count value N) count process in FIG. Further, the control unit 4 performs time measurement in the process shown in FIG. 12 in parallel with the time measurement process of the pulse period in FIG.

When the timed time reaches the estimation period t, the control unit 4 ends the timekeeping and ends the counting of the count value M (step S48). Next, the control unit 4 writes the count value M in the RAM or the storage unit 5 or both (step S49). The count value M is the number of pulses during a period (estimated period t) in which the power supply voltage of the motor 2 is fluctuating. Since the value obtained by multiplying the number of pulses (count value M) counted by the control unit 4 by a predetermined constant corresponds to the rotation amount of the motor 2 and the movement amount of the movable unit, the control unit 4 performs the estimation period t. The processing (step S41 to step S49) for counting the number of pulses (count value M) during the period corresponds to the processing in which the control unit 4 calculates the rotation amount of the motor 2 and the movement amount of the movable unit during the estimation period t. To do.
Then, after writing the count value M, the control unit 4 ends the process shown in FIG.

  As shown in FIG. 10, when the power supply voltage of the motor 2 changes abruptly during the operation of the motor 2, the control unit 4 temporarily assumes the motor 2 during the period in which the power supply voltage of the motor 2 is changing (estimated period t). The number of pulses in the case where the power supply voltage of the case does not fluctuate is estimated. Specifically, the control unit 4 estimates the number of pulses by executing a process as shown in FIG.

  The control unit 4 monitors the voltage data input from the A / D converter 7 and compares the voltage data with a predetermined threshold value (step S51). When the power supply voltage of the motor 2 fluctuates rapidly, the voltage data falls below the threshold value, so that the control unit 4 detects a sudden fluctuation of the voltage data (step S51: Yes).

  Next, the control part 4 sets the estimation period t (step S52). The estimation period t set in step S52 is the same as the estimation period t set in step S42.

  Next, the control unit 4 immediately before detecting the fluctuation of the power supply voltage of the motor 2 detected by the A / D converter 7 in the pulse period (see FIG. 11) for each pulse stored in the storage unit 5 or the RAM. A pulse period T_before for one pulse or a plurality of pulses (immediately before the estimation period t) is read (step S53). A value obtained by multiplying the inverse of the pulse period T_before by a predetermined constant corresponds to the rotation speed of the motor 2 immediately before the estimation period t and also corresponds to the speed of the movable part immediately before the estimation period t. Therefore, the process in which the control unit 4 reads the pulse cycle T_before (step S53) corresponds to the process in which the control unit 4 reads the rotational speed of the linear motor 2 and the speed of the movable part in the estimation period t.

  Next, in the pulse period (see FIG. 11) for each pulse stored in the storage unit 5 or the RAM, the control unit 4 outputs one pulse immediately after the estimated period t has elapsed since the power supply voltage of the motor 2 fluctuated. A pulse period T_after for minutes or a plurality of pulses is read (step S54). A value obtained by multiplying the reciprocal of the pulse period T_after by a predetermined constant corresponds to the rotation speed of the motor 2 immediately after the estimation period t and also corresponds to the speed of the movable part immediately after the estimation period t. Therefore, the process in which the control unit 4 reads the pulse cycle T_after (step S54) corresponds to the process in which the control unit 4 reads the rotation speed of the motor 2 and the speed of the movable part immediately after the estimation period t. If the estimation period t has not elapsed since the power supply voltage of the motor 2 fluctuated, the control unit 4 waits for the estimation period t to elapse, and then one pulse or a plurality of pulses immediately after the estimation period t has elapsed. Read the minute pulse period T_after.

  Next, the control unit 4 calculates an average period T_average between the pulse period T_before for one pulse or a plurality of pulses read in step S53 and the pulse period T_after for one pulse or a plurality of pulses read in step S54. (Step S55). Note that a value obtained by multiplying the inverse of the average period T_average by a predetermined constant corresponds to the average rotational speed of the motor 2 within the estimation period t and also corresponds to the average speed of the movable part within the estimation period t. Therefore, the process in which the control unit 4 calculates the average period T_average (step S55) corresponds to the process in which the control unit 4 calculates the average rotation speed of the motor 2 and the average speed of the movable part within the estimation period t.

Next, the control unit 4 calculates a quotient n obtained by dividing the estimated time t by the average period T_average (step S56). The quotient n is the estimated number of pulses when the power supply voltage of the motor 2 does not change during the period during which the power supply voltage of the motor 2 is changing (estimation period t). Hereinafter, the quotient n is also referred to as an estimated pulse number n.
Since the value obtained by multiplying the reciprocal of the average period T_average by a predetermined constant corresponds to the average rotational speed of the motor 2 and the average speed of the movable part within the estimation period t, the control unit 4 calculates the estimated time t as the average period. The process of obtaining the quotient by dividing by T_average (step S56) corresponds to the process of obtaining the product by the control unit 4 multiplying the estimation period t by the average rotational speed of the motor 2 or the average speed of the movable part. The product is the estimated amount of rotation of the motor 2 or the estimated amount of movement of the movable part when the power supply voltage of the motor 2 does not fluctuate during the period in which the power supply voltage of the motor 2 fluctuates (estimated period t). It is.

  After calculating the estimated number of pulses n, the control unit 4 ends the process shown in FIG.

  After obtaining the estimated number of pulses n in the process shown in FIG. 13, the control unit 4 counts M (the number of pulses during the estimation period t) counted in the process shown in FIG. 12 and the estimated pulse obtained in the process shown in FIG. Based on the number n, the count value N (number of pulses) being counted is corrected in the process being executed shown in FIG. Specifically, the control unit 4 estimates the number of pulses by executing a process as shown in FIG. That is, the control unit 4 subtracts the count value M from the count value N being counted, and adds the estimated pulse number n thereto. Then, the control unit 4 updates the count value N being counted to a value after addition / subtraction (step S61). As described above, the count value N is updated based on the count value M and the estimated pulse number n. Then, the control unit 4 executing the process shown in FIG. 9 adds 1 to the corrected count value N in the first step S24 after the end of the process shown in FIG. Update.

  Note that a value obtained by multiplying the count value N (number of pulses) updated by the control unit 4 by a predetermined constant corresponds to the amount of rotation after the motor 2 is updated or the amount of movement of the movable unit after the update. Therefore, the process in which the control unit 4 subtracts the count value M from the count value N (number of pulses) and adds the estimated number of pulses n thereto (step S61) is the rotation amount of the motor 2 being calculated by the control unit 4 (step S61). The product (corresponding to the estimated number of pulses n) calculated by subtracting the rotation amount (corresponding to the count value M) of the motor 2 in the estimation period t from the count value N) and multiplying the estimation period t by the average rotation speed of the motor 2 ) Is equivalent to the process of adding to it. Further, the process in which the control unit 4 subtracts the count value M from the count value N (number of pulses) and adds the estimated number of pulses n thereto (step S61) is the amount of movement of the movable part being calculated by the control unit 4 (step S61). The product (corresponding to the estimated number of pulses n) calculated by subtracting the moving amount (corresponding to the counted value M) of the movable part in the estimation period t from the count value N) and multiplying the estimation period t by the average rotational speed of the movable part. ) Is equivalent to the process of adding to it.

  What has been described above is the description of the operation of the motor control device 1. The motor control device 1 shown in FIG. 1 is used for a vehicle seat device, for example. The vehicle seat device includes the motor control device 1 shown in FIG. 1 and the seat body 90 shown in FIG. 15, and the movable part of the seat body 90 is driven by the motor 2. The number of movable parts of the sheet main body 90 and the number of motors 2 are preferably the same. When there are a plurality of motors 2, the motor driver 6 and the extraction circuit 3 are provided for each motor 2, and the control unit 4 and the storage unit 5 are common to all the motors 2.

  The sheet body 90 will be specifically described. The seat body 90 includes a rail 91, a seat bottom 92, a backrest 93, a headrest 94, an armrest 95, a legrest 96, and the like.

  The seat bottom 92 is mounted on the rail 91, the seat bottom 92 is provided so as to be movable in the front-rear direction by the rail 91, and the motor 2 drives the seat bottom 92 in the front-rear direction. The front part of the seat bottom 92 is provided to be movable up and down, and another motor 2 drives the front part of the seat bottom 92 in the vertical direction. The rear part of the seat bottom 92 is provided so as to be movable up and down, and another motor 2 drives the rear part of the seat bottom 92 in the vertical direction. The backrest 93 is rotatably connected to the rear end portion of the seat bottom 92 by a reclining mechanism, and another motor 2 raises and lowers the backrest 93 with respect to the seat bottom 92. The headrest 94 is connected to the upper end of the backrest 93 so as to be able to move up and down and rotate, and another motor 2 drives the headrest 94 in the vertical direction, and another motor 2 undulates the headrest 94 back and forth. The armrest 95 is rotatably connected to the side surface of the backrest 93, and another motor 2 drives the armrest 95 from the horizontal state to the vertical state and vice versa. A legrest 96 is rotatably connected to the front end portion of the seat bottom 92, and another motor 2 drives the legrest 96 from a flipped state to a suspended state or vice versa.

The embodiment of the present invention has the following effects.
(1) Even when the extraction circuit 3 cannot accurately extract the pulse component during the estimation period t during which the power supply voltage of the motor 2 will fluctuate, the control unit 4 performs pulses immediately before and immediately after the estimation period t. By dividing the estimation period t by the average value of the period, the number of pulses (quotient n) during the estimation period t is calculated (see FIG. 13). Then, the control unit 4 corrects the pulse number by adding the estimated pulse number (quotient n) to the pulse number (count value N) based on the output pulse signal of the extraction circuit 3 (see FIG. 14). Therefore, an accurate pulse number is obtained, and the rotation amount obtained by the control unit 4 accurately represents the actual rotation amount of the motor 2.
(2) Since the high cut-off frequency fc2 of the filter 40 is set lower than the frequency of the ripple component in the circuit design of the filter 40, the ripple component can be removed by the filter 40.
(3) The differential amplifier 50 outputs the output signal of the bandpass filter 30 (the voltage signal converted by the current-voltage converter 10 from which the DC component and the high-frequency noise component are removed) and the output signal of the filter 40. The difference between the voltage signals converted by the current-voltage converter 10 from which the DC component, the high-frequency noise component, the ripple component, etc. are removed is taken and output as a difference signal. Therefore, the output signal of the differential amplifier 50 is a ripple component in the voltage signal converted by the current-voltage converter 10. Because the output signal of the differential amplifier 50 is a differential signal, even if the frequency of each component of the current signal of the motor 2 fluctuates due to environmental changes, the ripple component is accurately extracted, Ripple can be detected with high accuracy.
(4) Of the frequency characteristics shown in FIG. 5, the output of the differential amplifier 50 can be obtained even if the frequency of the ripple component fluctuates due to temperature change because the sloped portion in the region higher than the high cutoff frequency fc2 is used. The signal is accurately extracted as a ripple component.
(5) Since the ripple component is extracted by the filter 40 and the differential amplifier 50 using the frequency characteristics of the filter 40, it is not necessary to use a variable cutoff frequency filter for the filter 40. Therefore, the cost of the filter 40 can be reduced.
(6) Since the extraction circuit 3 is not a closed loop circuit such as a feedback control circuit, ripples can be accurately detected even if the frequency of each component of the current signal of the motor 2 changes transiently or rapidly. .
(7) Since the filter 40 is a filter including resistors 41b, 41d, 41a, and 41c and capacitors 41a, 41c, 41b, 41d, and 43a, the configuration of the filter 40 is simple, and an increase in the cost of the filter 40 is suppressed. Can do.
(8) Since the ripple component is extracted by the filter 40 and the differential amplifier 50 using the frequency characteristics of the filter 40, it is not necessary to use a variable cutoff frequency filter for the high-pass filter 20 or the band-pass filter 30. Therefore, the cost increase of the high pass filter 20 and the band pass filter 30 can be suppressed.
(9) Since the DC component of the voltage signal converted by the current-voltage converter 10 is removed by the high-pass filter 20, the processing of the band-pass filter 30, the filter 40 and the differential amplifier 50 subsequent to the high-pass filter 20 is performed. Exactly done.
(10) Since the component outside the predetermined frequency band of the voltage signal converted by the current-voltage converter 10 is attenuated by the band-pass filter 30, the processing of the filter 40 and the differential amplifier 50 subsequent to the band-pass filter 30 is performed. Exactly done.

[Modification]
The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention. Hereinafter, modified examples will be described. The following modifications may be combined as much as possible.

[Modification 1]
In step S22 described above, the control unit 4 may set the count value N in the initial position data 5A instead of resetting the count value N to zero. In this case, the process in step S25 is omitted. Further, in step S24, the control unit 4 updates the count value N by adding or subtracting 1 to the count value N every time the pulse of the pulse signal output by the extraction circuit 3 is input. The control unit 4 determines the calculation in step S24 according to the direction determined in step S11. For example, when the rotation direction determined in step S11 is normal rotation, the control unit 4 performs addition in step S24, and when the rotation direction determined in step S11 is reverse rotation, the control unit 4 Performs subtraction in step S24. Of course, the relationship between the direction of rotation and the calculation may be reversed.
The count value N updated in step S24 indicates the rotational position of the motor 2 and the distance from the origin position with reference to the origin position.

[Modification 2]
The detection circuit 3 is an example, and is not limited to the circuit of the above-described embodiment. For example, the filter 40 and the differential amplifier 50 may be omitted. In this case, a switched capacitor filter is provided after the band-pass filter 30 and before the amplifier 60 so that the ripple component can be accurately extracted even if the frequency of the ripple component changes. preferable. Even when the cutoff frequency of the switched capacitor filter is variable and the frequency of the ripple component or the low frequency component changes, the switched capacitor filter attenuates the low frequency component and passes the ripple component.

[Modification 3]
In the circuit design of the filter 40, the low cut-off frequency fc1 of the filter 40 shown in FIG. 5 is set to be higher than the frequency of the ripple component (for example, the frequency at normal temperature) while taking into account fluctuations in the frequency of the ripple component due to temperature changes. Has been. Therefore, the filter 40 attenuates the ripple component of the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 higher than the high-frequency component (the high-frequency component has a higher frequency than the ripple component). Decay at a rate. That is, the filter 40 removes the ripple component more efficiently than the high frequency component. Therefore, the filter 40 outputs a signal from which the ripple component has been removed to the differential amplifier 50.

  In this case, the current signal of the motor 2 and the input signals of the filter 40 and the differential amplifier 50 are obtained by superimposing a ripple component and a high frequency component having a higher frequency than the ripple component.

[Modification 4]
The filter 40 may be a low-pass filter having frequency characteristics as shown in FIG. 16 instead of a band-pass filter. The filter 40 passes the component below the cutoff frequency fc3 among the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10, and attenuates the component exceeding the cutoff frequency fc3. Specifically, in a high frequency region exceeding the cut-off frequency fc3, the filter 40 decreases the attenuation rate as the frequency of the component included in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 decreases. Is attenuated so that the voltage signal converted by the current-voltage converter 10 (the output signal of the bandpass filter 30) is attenuated.

  In the circuit design of the filter 40, the cut-off frequency fc3 of the filter 40 shown in FIG. 16 is set to be lower than the frequency of the ripple component (for example, the frequency at normal temperature) while taking into account fluctuations in the frequency of the ripple component due to temperature changes. ing. Therefore, the filter 40 has a ripple component in the voltage signal (the output signal of the band pass filter 30) converted by the current-voltage converter 10 that is lower in frequency than the low frequency component (the frequency of the low frequency component is lower than that of the ripple component). Attenuate with high attenuation factor. That is, the filter 40 removes the ripple component more efficiently than the low frequency component. Therefore, the filter 40 outputs a signal from which the ripple component has been removed to the differential amplifier 50.

  In this case, the current signal of the motor 2 and the input signal of the filter 40 and the differential amplifier 50 are obtained by superimposing a ripple component and a low frequency component having a frequency lower than that of the ripple component.

  When the filter 40 is a low-pass filter, the high-pass filters 41 and 43 shown in FIG. 6 are omitted, the output of the band-pass filter 30 is connected to the input of the low-pass filter 42, and the output of the low-pass filter 42 is connected via the resistor 51. The inverting input terminal of the operational amplifier 53 is connected.

[Modification 5]
The filter 40 may be a high-pass filter having frequency characteristics as shown in FIG. 17 instead of the band-pass filter. The filter 40 passes a component having a cutoff frequency fc4 or higher in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10, and attenuates a component lower than the cutoff frequency fc4. Specifically, in the low frequency region below the cut-off frequency fc4, the filter 40 attenuates as the frequency of the component included in the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 decreases. The voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 is attenuated so that the rate becomes higher.

  In the circuit design of the filter 40, the cut-off frequency fc4 of the filter 40 shown in FIG. 17 is set to be higher than the frequency of the ripple component (for example, the frequency at normal temperature) while taking into account fluctuations in the frequency of the ripple component due to temperature changes. ing. Therefore, the filter 40 attenuates the ripple component of the voltage signal (the output signal of the bandpass filter 30) converted by the current-voltage converter 10 higher than the high-frequency component (the high-frequency component has a higher frequency than the ripple component). Decay at a rate. That is, the filter 40 removes the ripple component more efficiently than the high frequency component. Therefore, the filter 40 outputs a signal from which the ripple component has been removed to the differential amplifier 50.

  When the filter 40 is a high pass filter, the low pass filter 42 shown in FIG. 6 is omitted, and the output of the band pass filter 30 is connected to the input of the high pass filter 41.

[Modification 6]
The filter 40 may be a band stop filter instead of a band pass filter.

[Modification 7]
One or both of the high pass filter 20 and the band pass filter 30 may be omitted. When the high-pass filter 20 is omitted, the output of the current-voltage converter 10 is connected to the input of the band-pass filter 30. When the band pass filter 30 is omitted, the output of the high pass filter 20 is connected to the input of the filter 40 and the input of the differential amplifier 50. When both the high-pass filter 20 and the band-pass filter 30 are omitted, the output of the current-voltage converter 10 is connected to the input of the filter 40 and the input of the differential amplifier 50.

[Modification 8]
The motor control device 1 is incorporated in an electric door mirror device, and a movable part of the electric door mirror device (for example, a storage mechanism that stores and unfolds the mirror housing with respect to the door, a tilt mechanism that swings the mirror up and down with respect to the mirror housing, a mirror) A pan mechanism that swings the mirror to the left and right with respect to the housing may be driven by the motor 2 of the motor control device 1. The motor control device 1 may be incorporated in the power window device, and the movable portion (for example, window regulator) of the power window device may be driven by the motor 2.

[Modification 9]
The filter 40 may use an operational amplifier (for example, a negative feedback low-pass filter, a positive feedback low-pass filter, a multiple negative feedback band-pass filter, or a multiple positive feedback band-pass filter).

2 Motor 3 Extraction circuit 4 Control unit 5 Storage unit 7 A / D converter (voltage detection unit)

Claims (6)

A motor that generates a periodic ripple in the current signal when driven;
An extraction circuit that extracts a ripple component from the current signal of the motor and outputs a pulse signal obtained by pulsing the ripple component;
A voltage detector for detecting the voltage of the motor;
A controller that inputs the pulse signal and controls the motor;
The control unit is
A first process for counting the number of pulses of the pulse signal;
A second process of measuring the pulse period of the pulse signal for each pulse of the pulse signal and sequentially storing the measured pulse period;
In the case where a change in voltage detected by the voltage detector is detected, one pulse or a plurality of pulses immediately before detecting a change in voltage detected by the voltage detector in the pulse period stored in the second process Among the pulse period for the pulse and the pulse period stored in the second process, the pulse period for one pulse or a plurality of pulses after a predetermined period has elapsed since the detection of the voltage variation detected by the voltage detection unit A third process for calculating an average period with
And a fourth process of calculating a quotient obtained by dividing the predetermined period by the average period calculated in the third process. The control unit is
A fifth process of counting the number of pulses of the pulse signal during the predetermined period when detecting a variation in the voltage detected by the voltage detector;
The sixth process of further subtracting the number of pulses counted in the fifth process from the number of pulses counted in the first process and adding the quotient calculated in the fourth process to the sixth process. Motor control device.   The motor control device according to claim 2, wherein the control unit further executes a seventh process of updating the number of pulses counted in the first process to a value obtained by addition and subtraction of the sixth process. A motor that generates a periodic ripple in the current signal when driven;
An extraction circuit that extracts a ripple component from the current signal of the motor and outputs a pulse signal obtained by pulsing the ripple component;
A voltage detector for detecting the voltage of the motor;
A controller that inputs the pulse signal and controls the motor;
The control unit is
A first process for calculating the amount of rotation of the motor by counting the number of pulses of the pulse signal;
A second process of calculating the rotational speed of the motor for each pulse of the pulse signal by measuring the pulse period of the pulse signal for each pulse of the pulse signal, and sequentially storing the calculated rotational speed;
When a voltage variation detected by the voltage detector is detected, out of the rotation speed stored in the second process, one pulse or a plurality of pulses immediately before detecting the voltage variation detected by the voltage detector The rotation speed for one pulse or a plurality of pulses after a predetermined period of time has elapsed after detecting the fluctuation of the voltage detected by the voltage detection unit among the rotation speed for the pulse and the pulse period stored in the second process A third process for calculating an average rotation speed with
And a fourth process of calculating a product obtained by multiplying the average rotation speed calculated in the third process during the predetermined period. The control unit is
A fifth method for calculating the amount of rotation of the motor during the predetermined period by counting the number of pulses of the pulse signal during the predetermined period when a change in the voltage detected by the voltage detection unit is detected. Processing,
5. The sixth process of subtracting the rotation amount calculated in the fifth process from the rotation amount calculated in the first process and adding the product calculated in the fourth process to the sixth process is further executed. Motor control device.   The motor control device according to claim 5, wherein the control unit further executes a seventh process of updating the rotation amount calculated in the first process to a value obtained by addition and subtraction of the sixth process.

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