JP2002325475A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position controller of a movable unit which can detect very low revolution, even when a motor rotates with a very low revolution speed since its start time and avoid misdetection of a very low-speed revolution in a revolution revolution region, in which ripple pulses can be detected. SOLUTION: When the difference between a maximum value of a rush current at the start time of a motor and a steady current is lower than a prescribed threshold (step S114: Yes), it is discriminated that the motor is rotating with a very low-speed revolution by a step S115. If a motor load is increased, the difference between both the currents is reduced, and if the difference is smaller than a prescribed threshold, it is discriminated that the motor is rotating with a very low revolution. Therefore, it can be detected that the motor rotates with very low-speed revolution in a range where ripple pulses cannot be detected accurately, when the motor is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable body position control device for driving a movable body of a vehicle-mounted functional component such as a memory sheet, a power window and a sunroof by a motor.

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as an automobile, the seat position is adjusted to a desired position in accordance with the occupant's body shape, the seat position is stored in a memory, and then, when a reproduction switch is pressed, the seat is stored. A memory sheet that is automatically set at the set position is used.

The memory seat is provided with a slide motor for moving the entire seat back and forth, a reclining motor for tilting the seat back back and forth, and the like. By driving these motors by operating the operation switches, the seat position can be adjusted to a desired position, and the seat position can be stored by the storage switch. For example, in the prior art disclosed in Japanese Patent Application Laid-Open No. 8-47293, a ripple component included in a drive current of a DC motor for driving a sheet is converted into a ripple pulse synchronized with the motor through a pulse generation circuit using a differentiation circuit. Detected as
The position control and the state storage of the sheet are performed based on the pulse.

However, in the above-mentioned conventional technology, the ripple component included in the driving current cannot be accurately pulsed when the motor is rotating at an extremely low speed due to the characteristics of the differentiating circuit.

[0005] This will be described with reference to FIG. As shown in FIG. 19 (a), when the motor rotates at a rotation speed where the frequency of the ripple pulse exceeds 90 Hz, for example, the ripple component can be accurately pulsed, and the normal rotation synchronized with the rotation of the motor can be performed. A ripple pulse is obtained.

On the other hand, as shown in FIG. 19B, when the motor rotates at a rotation speed at which the frequency becomes 90 Hz, the drive current is changed from the normal sine wave shown in FIG. It becomes distorted waveform and contains noise. For this reason, the signals of the differentiation 1 and the differentiation 2 are shown in FIG.
The waveform becomes distorted from the normal waveform shown in FIG. as a result,
The ripple component cannot be accurately pulsed, and FIG.
A ripple pulse including a pulse having a pulse width different from that of the normal pulse shown in FIG. 9A is output (pulse change occurs). Further, as shown in FIG. 19C, when the motor rotates at a rotation speed at which the frequency is less than 90 Hz, the drive current has a waveform closer to a trapezoid that is further distorted than in the case of FIG. 19B. Together with more noise. For this reason, the signals of differentiation 1 and differentiation 2 are shown in FIG.
The waveform is different from that of the normal waveform shown in FIG. 9A and has a different frequency. As a result, the ripple component cannot be accurately pulsed, and a ripple pulse having a larger number of pulses than in the normal state shown in FIG. 19A is output (pulse increase occurs).

Various measures can be taken for the above-described pulse change or pulse increase, but at that time, there has been a problem that it becomes impossible to detect the extremely low speed rotation of the motor from another aspect. .

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to reliably detect an extremely low speed rotation of a motor under various environments.

[0009]

A first means for solving the above problems is a current detecting means for detecting a drive current of a motor, and outputting a ripple pulse obtained by pulsing a ripple component included in the drive current. In a control device including a pulse detection unit and a control unit that controls driving of a motor based on a ripple pulse, the control unit calculates a difference between an inrush current when the motor is started and a steady current detected by the current detection unit. If the difference is smaller than the predetermined value, it is determined that the motor is rotating at an extremely low speed equal to or lower than the predetermined rotation speed.

Here, the extremely low speed rotation means a state where the motor is rotating at a low rotation speed (rotational speed) at which the ripple component cannot be accurately pulsed by the pulse detection means and the ripple pulse cannot be detected accurately. Say. For example, when 10 ripple pulses are detected in one rotation of the motor,
The state where the motor is rotating at a rotation speed of 600 rpm or less (a rotation speed at which the frequency of the ripple pulse is 100 Hz or less) is “extremely low speed rotation”.

According to this means, when the difference between the inrush current (drive current) at the time of starting the motor and the steady current (drive current) is smaller than a predetermined value, the control means determines that the motor is rotating at an extremely low speed. You. Therefore, when the motor is started, it can be detected that the motor is rotating at an extremely low speed at which the ripple pulse cannot be accurately detected.

The current-rotational speed characteristics of the motor (see FIG. 9) vary greatly from motor to motor within a range shown by hatching in FIG. However, as can be seen from the figure, even if the characteristics of each motor vary greatly, the inclination of the characteristics of each motor does not change. Therefore, if the difference between the inrush current and the steady-state current is equal to or larger than a predetermined threshold value (width indicated by reference numeral 58), it is determined that the motor is not rotating at an extremely low speed, so that this determination is not affected by the variation in the characteristics. . Therefore, unlike the above-described prior art, the extremely low-speed rotation of the motor is not erroneously detected in a rotation range where the ripple pulse can be detected (for example, a region on the higher rotation side than the motor extremely low-speed rotation position indicated by reference numeral 59). .

[0013] A second means for solving the above problems is as follows.
In addition to the first means, the control means sets the predetermined value based on the power supply voltage at the time of the inrush current and the power supply voltage at the time of the steady current. According to this means, even when a difference occurs between the power supply voltage at the time of the inrush current and the power supply voltage at the time of the steady current,
The extremely low-speed rotation of the motor can be accurately detected without being affected by the fluctuation of the power supply voltage.

[0014] A third means for solving the above problems is as follows.
In addition to the first or second means, the control means includes a period setting means for setting a certain period from the start of the motor until the drive current is stabilized, and detects the extremely low speed rotation of the motor only within the certain period. That is. According to this means,
Generally, the current-rotation speed characteristic of a motor is affected by a change in the temperature of the motor. However, the detection of the extremely low-speed rotation of the motor is performed only during a certain period from the start of the motor. Therefore, by setting the synchronous period to a short period in which heat generation of the motor is extremely small, it is possible to accurately detect the extremely low-speed rotation of the motor without affecting the characteristics due to the temperature change.

[0015] A fourth means for solving the above problems is as follows.
In addition to any one of the first to third means, the control means sets a maximum current of the drive current within a second fixed time period from the start of the motor as an inrush current, and after a lapse of the second fixed time period, sets the That is, the current when the drive current is stabilized within the fixed period of No. 3 is defined as a steady current. According to this means, the difference between the inrush current and the steady current is not affected by the fluctuation of the power supply voltage, and the extremely low speed rotation of the motor can be accurately detected by comparing this current difference with the threshold value.

A fifth means for solving the above-mentioned problems is as follows.
Control comprising: current detection means for detecting a drive current of a motor; pulse detection means for outputting a ripple pulse obtained by pulsating a ripple component included in the drive current; and control means for controlling drive of the motor based on the ripple pulse. In the device, when the cycle of the ripple pulse exceeds the second predetermined value, the control means determines that the motor is rotating at an extremely low speed equal to or lower than the predetermined rotation speed, and the drive current has decreased below the third predetermined value. In other words, the above determination is invalidated within a fourth fixed period thereafter.

According to this means, when the cycle of the ripple pulse exceeds the second predetermined value, it is determined that the motor is rotating at an extremely low speed. However, in the state where the large-capacity actuator such as the starter motor is operated during the operation of the motor and the power supply voltage sharply drops, the drive current drops below the third predetermined value, and during the fourth fixed period thereafter, Even if the cycle of the ripple pulse exceeds a predetermined threshold, it is not determined that the motor is rotating at an extremely low speed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a motor control device according to the present invention is applied to a memory sheet device mounted on a vehicle will be described below. In each embodiment, the same portions are denoted by the same reference numerals, and duplicate description will be omitted.

First, the control device according to the first embodiment will be described. FIG. 5 schematically shows the entire configuration of a position control device 21 for controlling the position of each sheet (movable body) of a memory sheet device. I have. The position control device 21 is an electronic control unit (hereinafter referred to as “EC
U ”) 22).

The ECU 22 includes a CPU 2 serving as control means.
3. A ROM, a RAM, a backup RAM, and the like, each of which is not shown, are provided. The ROM is a memory in which various control programs, maps referred to when executing these programs, and the like are stored. The CPU 23 uses the RO
The arithmetic processing is executed based on various control programs and maps stored in M. The RAM is a memory for temporarily storing the result of operation by the CPU 23 and data input from the outside, and the backup RAM is a non-volatile memory for storing the stored data and the like. And CPU
The ROM 23, the ROM, the RAM, and the backup RAM are connected to each other via a bus (not shown), and are also connected to the input interface circuit 24 and an output interface circuit (not shown).

A battery (BAT) 26 is connected to the CPU 23 via a power supply circuit 25 inside the ECU 22. The positive terminal of the battery 26 is connected to the input interface circuit 24 via an ignition switch (IGSW) 27. When the IG switch 27 is turned on, a constant voltage (for example, 5 V) stabilized by the power supply circuit 25 is input to the CPU 23.

Input interface circuit 2 of CPU 23
An operation switch 28 for adjusting the position (sheet state) of each part of the seat is connected to 4. The operation switches 28 include slide switches 29a and 29b, reclining switches 30a and 30b, front vertical switches 31a and 31b, and lifter switches 32a and 32.
2b.

Further, in addition to the operation switch 28, memory reproduction switches 33 and 34 and a storage switch 35 are connected to the input interface circuit 24. The memory reproduction switches 33 and 34 are switches for storing two sheet positions for one sheet.
By operating each of the operation switches 28, each part of the seat can be adjusted to a desired seat position (sheet state).
The adjusted sheet position is stored in a memory (for example, RA
To store the data in M), one of the reproduction switches 33 and 34 is pressed together with the storage switch 35. Thereafter, when one of the reproduction switches 33 and 34 is pressed, each part of the sheet is automatically moved to the stored sheet position.

The output interface circuit of the CPU 23 is connected to four motors 39 to 42 via a group of relays 43. These motors are DC brush motors. The relay group 43 includes four sets of relays respectively corresponding to the four motors 39 to 42, and each motor is connected to the output interface circuit via a corresponding set of relays. Each set of relays includes a pair of coils and a pair of switching terminals. When any one of the operation switches 28 is operated, the CPU 23 controls the energization of a set of coils corresponding to the operated switch. As a result, the switching terminals of the same set of relays are switched, and the motor 3
Of the relays 9 to 42, the motors corresponding to the same set of relays are independently driven to rotate forward or reverse.

That is, the slide motor 39 rotates forward or backward by operating the slide switches 29a and 29b to slide the entire sheet forward / backward. The reclining motor 40 includes reclining switches 30a, 3
The seatback is rotated forward or backward by the operation of 0b to tilt the seat back forward / backward. The front vertical motor 41 rotates forward or backward by operating the front vertical switches 31a and 31b to move the front portion of the seat cushion up / down. Then, the lifter motor 42 rotates forward or backward by operating the lifter switches 32a and 32b to move the rear portion of the seat cushion up / down.

The ECU 22 includes motors 39-4.
Ripple pulse detection circuit 5 as pulse detection means for pulsating a ripple component included in the drive current of the motor flowing through the motor 2 and outputting a ripple pulse synchronized with the motor
0 and an amplifier circuit 51 for amplifying the drive current. A motor rotation signal obtained by converting a drive current into a signal having a voltage value proportional to the current value by the resistor 52 is input to the ripple pulse detection circuit 50.
The drive current amplified by the amplifier circuit 51 is supplied to the ECU 2
A / D converted by the A / D converter provided in CPU 2
23. Thus, CP
U23 always detects the drive current of each of the motors 39 to 42. The amplification circuit 51 and the A / D converter constitute current detection means for detecting a drive current.

The ripple pulse detecting circuit 50 is a switched capacitor filter (SCF) not shown.
And a ripple pulse shaping circuit 53 shown in FIG. The motor rotation signal is input to the SCF.
The SCF removes noise included in the motor rotation signal together with the ripple component at a predetermined cutoff frequency.

As shown in FIG. 6, the ripple pulse shaping circuit 53 includes a low-pass filter LPF (high-frequency active filter), a first differentiating circuit DC1, an amplifier AP,
It includes a second differentiating circuit DC2, a comparator CM, and the like.

The low-pass filter LPF removes noise (noise generated by a clock signal that makes the cutoff frequency of the SCF variable) included in the output signal of the SCF (the signal of the SCF cutoff shown in FIG. 18). The output signal of the SCF from which the noise has been removed is differentiated by the first differentiating circuit DC1 to attenuate the DC component, and a signal having only a ripple component (a signal of the differential 1 shown in FIG. 19A) is obtained. When this signal is amplified by the amplifier AP and then passed through the second differentiating circuit DC2, a signal delayed by 90 ° with respect to the signal (a differential 2 signal shown in FIG. 19A) is obtained. And
By comparing the output signal of the amplifier AP and the output signal of the second differentiating circuit DC2 with the comparator CM, each motor 39
Synchronous with the rotations of .about.42, a ripple pulse (see FIGS. 18 and 19) having a frequency corresponding to the rotation speed (rotation speed) is obtained.

The ripple pulses detected by the ripple pulse detection circuit 50 in synchronization with the rotation of each of the motors 39 to 42 and having a frequency corresponding to the number of rotations are output to the CPU 23 via the output interface circuit.

The low-pass filter LPF of the ripple pulse shaping circuit 53 shown in FIG.
The specific configurations of the amplifier AP, the second differentiating circuit DC2, and the comparator CM are disclosed in Japanese Patent Application Laid-Open No. 2000-242336, and thus description thereof will be omitted.

Next, various processes executed by the CPU 23 will be described with reference to flowcharts shown in FIGS.
Each of these processes is executed at a predetermined control cycle, for example, every 2 ms. In addition, since these processes are performed similarly for the four motors 39 to 42, in the following description, only one of the motors will be described without reference numerals.

First, the "ripple pulse counting process" and the "pulse edge detection process" executed by the CPU 23 will be described with reference to FIGS. Note that these 2
The two processes, which are shown separately in FIGS. 2 and 3, are executed as a series of processes.

First, the "pulse edge detection process" shown in FIG. 3 will be described. In step S301, it is determined whether or not the motor is operating. When the motor is stopped, the process proceeds to step S302, and when the motor is operating, the process proceeds to step S303.

In step S302, when the motor is stopped, no ripple pulse is output from the ripple pulse detection circuit 50, so that the pulse edge detection flag is set to "0". After this setting, the process of FIG. 3 is temporarily terminated.

In step S303, it is determined whether a pulse edge has been detected. The detection of the pulse edge here is performed, for example, by detecting the rise of a ripple pulse. If no pulse edge is detected, the process proceeds to step S302, and if a pulse edge is detected, the process proceeds to step S304.

In step S304, since a pulse edge has been detected, the pulse edge detection flag is set to "1". After this setting, the process of FIG. 3 is temporarily terminated. In this manner, when the rising edge (pulse edge) of the ripple pulse output from the ripple pulse detection circuit 50 is not detected by the pulse edge detection processing, the pulse edge detection flag is set to “0” and the pulse edge is detected. In this case, the flag is set to “1”.

Next, the "ripple pulse counting process" shown in FIG. 2 will be described. In step S201, it is determined whether the motor is operating. When the motor is stopped, the process proceeds to step S202, and when the motor is operating, the process proceeds to step S203.

In step S202, the pulse counter value of the ripple pulse counter is set to "0". After this setting, the process of FIG. 2 is temporarily terminated. Step S20
In 3, it is determined whether the pulse edge detection flag is set to “1”. Step S302 in FIG. 3
If the pulse edge detection flag is set to "0" in step (2), the processing in FIG. On the other hand, if the pulse edge detection flag is set to “1” in step S304, the process proceeds to step S204.

In step S204, the pulse counter value of the ripple pulse counter is incremented by "1". Thereafter, the process proceeds to step S205. Step S2
In 05, the pulse edge detection flag is set to "0". After this setting, the process of FIG. 2 is temporarily terminated.

Thus, in the ripple pulse counting process of FIG. 2, every time the pulse edge of the ripple pulse is detected, the pulse counter value of the ripple pulse counter is increased by one and the pulse edge detection flag is set to "0".
Set to. When the motor stops, the pulse counter value of the ripple pulse counter is reset to “0”.

Next, the "Startup 10" executed by the CPU 23 is executed.
The detection process at 0 Hz or lower (the process of detecting the extremely low-speed rotation of the motor at startup) will be described with reference to FIG. First, in step S101, it is determined whether the motor is operating. If the motor is stopped, the process of FIG. 1 is terminated. If the motor is operating, the process proceeds to step S102.

In step S102, it is determined whether the pulse counter value of the ripple pulse counter is equal to or less than a predetermined value a. If the count value is equal to or smaller than a, the process proceeds to step S103. If the count value exceeds the predetermined value a, the process proceeds to step S107. That is, in step S102, the current time is the first period (the second constant period) from the start of the motor until the pulse count value, which has started counting, exceeds the predetermined value a (the 1-a pulse period shown in FIG. 7). Is determined. If the current time is within the first period, the process proceeds to step S103, and the current time is after the first period and is in the second period (third fixed period) (a + shown in FIG. 7).
(1 to b pulse period), the process proceeds to step S107.

In step S103, it is determined whether or not the pulse count value is "1". Immediately after the motor is started, the count value is "1", so that the step S104
Proceed to.

In step S104, the read value (current current value) of the current drive current input from the amplifier circuit 51 via the A / D converter is converted to the maximum value (ai) of the inrush current ai.
MAX). After this setting, step S10
Go to 5.

In step S105, step S104
The drive current set as aiMAX at (inrush current a
i) The read value (current power supply voltage value) of the power supply voltage of the battery 26 at the time of reading the power supply voltage value av at the inrush current
Set as After this setting, the process of FIG. 1 is temporarily terminated.

Thereafter, when the process proceeds to step S103,
While the pulse count value is 2 or more and a or less, the process proceeds to step S106. In step S106, the current value is set to the value of aiMA set in step S104.
It is determined whether X is exceeded. The current value is ai
In the case of MAX or less, the processing of FIG. 1 is temporarily terminated.
On the other hand, if the current value exceeds aiMAX,
Steps S104 and S105 are executed to update aiMAX and av with the current current value and the current power supply voltage value, respectively.

As described above, after the motor is started, the first period (1 shown in FIG. 7) until the pulse count value exceeds the predetermined value a.
~ A pulse period) the maximum drive current value is the inrush current a
It is set as the maximum value aiMAX (rush current) of i.
At the same time, the power supply voltage at the time of reading the maximum value aiMAX is set as the power supply voltage av at the time of inrush current. Then, when the pulse count value exceeds the predetermined value a, that is, the current time passes the first period and the second period (a + 1 to a + 1 shown in FIG. 7).
Upon entering the (b pulse period), the process proceeds to step S107.

In step S107, it is determined whether the pulse counter value has exceeded a predetermined value (a + b).
If the count value is equal to or less than (a + b), step S
Proceeding to 108, if the count value exceeds (a + b),
The process of FIG. 1 is temporarily terminated. That is, step S107
Then, it is determined whether or not the current time is within the second period. Steps S102 and S107 correspond to "period setting means". Further, the sum of the first period and the second period can be set as the first predetermined period.

In step S108, it is determined whether the pulse count value is equal to (a + b). If the current time is immediately after the second period, the pulse count value is less than (a + b), and the process proceeds to step S109.

In step S109, it is determined whether or not the pulse count value is equal to (a + 1). If the current time is immediately after entering the second period, the pulse count value becomes (a
+1), the process proceeds to step S110.

In step S110, the read value (current current value) of the current drive current input from the amplifier circuit 51 via the A / D converter is converted to the maximum value (bi) of the steady current bi.
MAX). After this setting, step S11
Proceed to 1.

In step S111, step S110
The drive current set as biMAX at (the steady current b
The read value (current power supply voltage value) of the power supply voltage at the time of reading i) is set as the power supply voltage value bv at the time of steady current. After this setting, the process of FIG. 1 is temporarily terminated.

Thereafter, while the pulse count value is more than (a + 1) and less than (a + b), the above-mentioned step S1 is performed.
07 to step S109 are executed, and the process proceeds to step S112.

In step S112, the ratio of the current value to the current power supply voltage value (current current value / current power supply voltage value)
Is the biMA set in steps S110 and S111, respectively.
It is determined whether or not a ratio (biMAX / bv) between X (the previous value of the drive current) and bv (the previous value of the power supply voltage) is larger.
If the result of this determination is YES, that is, if the rate of change of the drive current with respect to the change in power supply voltage is greater than the previous rate of change, it can be determined that the motor has not yet transitioned to steady-state rotation. Therefore, when the determination result of step S112 is YES, the above-described steps S110 and S11
1 and the current current value and the current power supply voltage value
Update MAX and bv respectively. After this update, the processing of FIG. 1 is temporarily terminated.

Thereafter, step S112 is executed until the pulse count value becomes equal to (a + b). Until the current value of the change rate becomes equal to or less than the previous value (until the two change rates match), the above-described step S is performed.
Steps 110 and S111 are executed respectively, and biMAX and bv are updated respectively.

Thereafter, when the pulse count value becomes equal to (a + b), the decision result in the step S108 becomes YES, and the process proceeds to a step S113. In step S113, a is set in steps S105 and S111.
By searching the map stored in the ROM based on the values of v and bv, a threshold (first difference) to be compared with the difference between aiMAX and biMAX (difference between inrush current and steady current)
Is set.) After this, (aiMAX-biM
AX) (not shown), and proceeds to step S114.

In step S114, the current difference (aiMA
X-biMAX) is smaller than the above threshold value. If the current difference is equal to or greater than the threshold value, it can be determined that the motor is rotating at a rotation speed (e.g., extremely low speed rotation or more, for example, 600 rpm or more) where the frequency of the ripple pulse exceeds 100 Hz. Once terminated. In this case, the operation of the motor is continued. On the other hand, if the current difference is smaller than the threshold, the process proceeds to step S115.

In step S115, the number of rotations at which the frequency of the ripple pulse becomes 100 Hz or less when the motor is started (the number of rotations is extremely low speed or less, for example, 600 rpm or less).
It is determined that the motor is rotating, and the start flag of 100 Hz or less is set to "1" at startup. After this setting, this processing is temporarily ended.

If it is determined in step S115 that the frequency is equal to or less than 100 Hz, the motor can be stopped, or in the case of a memory sheet, control can be performed to clear the sheet position information stored in the memory. .

As described above, in the processing of FIG.
Is smaller than the threshold, it is determined that the motor is rotating at an extremely low speed.

Next, the “steady region 10” executed by the CPU 23
The detection process at 0 Hz or less will be described with reference to FIG. First, in step S401, it is determined whether the motor is stopped. If it is operating, step S40
The operation proceeds to step S403 if the operation is in progress.

In step S402, the pulse cycle count value of the pulse cycle counter is set to "0". After this setting, the processing in FIG. 4 is temporarily terminated. Step S403
Then, as in step S107 shown in FIG. 1, it is determined whether the pulse counter value exceeds a predetermined value (a + b). If the count value is equal to or less than (a + b), the second period has not elapsed since the motor was started.
Proceed to step S402. On the other hand, the count value is (a +
b), the second period has elapsed since the motor was started, and the motor is rotating in the steady range.
Proceed to step 404.

In step S404, it is determined whether the pulse edge detection flag has been set to "1".
If the pulse edge detection flag is set to “0” in step S205 shown in FIG. 2 or step S302 shown in FIG. 3, the process proceeds to step S402. On the other hand, FIG.
If the pulse edge detection flag is set to "1" in step S304 shown in (3), the process proceeds to step S405.

In step S405, the pulse cycle count value of the pulse cycle counter is incremented by "1". Thereafter, the process proceeds to step S406. Step S40
At 6, it is determined whether the pulse cycle count value is 6 or more. When the pulse period count value is less than 6, FIG.
Is temporarily terminated. On the other hand, if the pulse cycle count value is 6 or more, the process proceeds to step S407.

In step S407, it is determined that the motor is rotating at a rotation speed at which the frequency of the ripple pulse is 100 Hz or less (a rotation speed at an extremely low speed or less). When the motor is operating in the steady state, the frequency of the ripple pulse is 10
0 Hz or less (less than very low speed, for example 60
It is determined that the motor is rotating at a rotation speed of 0 rpm or less, and the determination flag is set to “1” in a steady range of 100 Hz or less. Further, in the present embodiment, when the determination is made in step S <b> 407 that the steady range is 100 Hz or less, the motor is stopped. Alternatively, in the case of a memory sheet, the information on the sheet position stored in the memory is cleared. Thereafter, this processing is temporarily ended.

As described above, in the process of FIG. 1, when the second period has elapsed after the motor is started and the motor is rotating in the steady range, the pulse period count value which has started counting when the second period has elapsed. Is 6 or more, an extremely low speed rotation of the motor is detected.

According to the first embodiment configured as described above, the following operation and effect can be obtained. (A) When the difference between the maximum value aiMAX of the inrush current and the maximum value biMAX of the steady-state current is smaller than the threshold value (step S11)
4 (YES), it is determined in step S115 that the motor is rotating at an extremely low speed.

This is done for the following reason. As shown in FIGS. 8A and 8B, the rotation speed of the motor after starting is stabilized at a lower rotation speed as the motor load increases. For this reason, compared with the low load state shown in FIG.
At the time of high load shown in FIG. 8B, the steady current becomes higher. On the other hand, as is clear from FIGS. 8A and 8B, the inrush current is almost constant without being affected by the motor load. This is because the inrush current is a value obtained by subtracting the reactance effect of the motor coil from the restraint current (drive current when the motor is stopped) and is not affected by the motor load.

As described above, as the motor load increases, the difference between the inrush current and the steady-state current (aiMAX-
biMAX) becomes smaller, and if this difference is smaller than the threshold value, it can be determined that the motor is rotating at an extremely low speed.
Therefore, when the motor is started, it can be detected that the motor is rotating at an extremely low speed at which the ripple pulse cannot be accurately detected.

(B) As shown in FIG. 9, the characteristics of the current-rotational speed of the motor greatly vary from motor to motor within the range shown by the diagonal lines in FIG. In the figure, reference numeral 55 indicates the characteristics of the sample motor, reference numeral 56 indicates the characteristics of a certain motor, and
Reference numeral 57 indicates the characteristics of another motor. As can be seen from the characteristics of these motors, even if the characteristics of each motor vary greatly, the inclination of the characteristics of each motor does not change.

Therefore, as in the present embodiment, (aiM
If (AX-biMAX) is equal to or larger than the width (the threshold value) indicated by reference numeral 58 in FIG. 9 (NO in step S114 in FIG. 1).
), It is determined that the rotation is not extremely low speed,
This determination is not affected by the variation in the characteristics.
Therefore, unlike the above-described prior art, the extremely low-speed rotation is not erroneously detected in the rotation region where the ripple pulse can be detected (the region on the higher rotation side than the motor extremely low-speed rotation indicated by reference numeral 59 in the figure). As a result, it is possible to eliminate a situation in which the extremely low-speed rotation is erroneously detected and the motor is stopped although the motor should not be stopped.

(C) Appropriate processing such as stopping the motor can be performed after the detection of the extremely low-speed rotation of the motor, thereby preventing each part of the seat from being controlled to an incorrect position. For example, it is possible to prevent the storage position of the memory sheet from being largely deviated, and to prevent the sheet from being moved to a position that is largely deviated from the storage position during reproduction of the sheet position.

(D) In step S114, the difference between the amplified inrush current and the steady current (aiMAX-biMA
Since X) can be compared with the threshold value, the extremely low-speed rotation of the motor can be detected more accurately.

(E) Since the threshold is set as in step S113, the extremely low-speed rotation can be accurately detected without being affected by the fluctuation of the power supply voltage. That is, even when a difference occurs between the power supply voltage at the time of the inrush current and the power supply voltage at the time of the steady current, the extremely low-speed rotation of the motor can be accurately detected without being affected by the fluctuation of the power supply voltage.

(G) In general, the current-rotation speed characteristic of a motor is affected by a change in the temperature of the motor. However, detection of extremely low speed rotation is performed only for a predetermined period from the start of the motor. The certain period is a period from the time of activation until the pulse count value exceeds (a + b) and becomes NO in step S107. For this reason, by setting the fixed period to a short period in which the heat generation of the motor is extremely small, it is possible to accurately detect the extremely low speed rotation without affecting the characteristics of the motor due to the temperature change.

(H) By step S107, there is no need to generate a clock signal or the like for measuring a fixed period from the start of the motor, and the circuit configuration can be simplified. (I) Steps S102, S107, S104, S10
6, the processing of S110 and S112 allows the maximum value of the drive current in the first period to be the inrush current, and the drive current when the change rate becomes maximum to be the steady current in the second period. Therefore, the difference between the inrush current and the steady current is not affected by the fluctuation of the power supply voltage, and the extremely low-speed rotation can be accurately detected by comparing the current difference with the threshold.

Next, the control device according to the second embodiment is
This will be described with reference to FIGS. In the position control device 21 according to the present embodiment, when the period of the ripple pulse exceeds a predetermined threshold value in a state where no sudden change in the power supply voltage of the It is determined that the rotation speed is low (100 Hz or less).

In other words, as shown in FIGS. 10 and 11, when the large-capacity actuator such as the starter motor is operated during the operation of the motor and the power supply voltage is rapidly reduced, the cycle of the ripple pulse is not fixed. Even if the threshold value is exceeded, it is not determined that the motor is rotating at an extremely low speed.

First, the "motor extremely low speed rotation detection process" executed by the CPU 23 will be described with reference to FIG. In this process, ten ripple pulses are detected per one rotation of the motor, and when the cycle of the ripple pulse exceeds the motor extremely low-speed rotation (10 ms), it is determined that the motor is extremely low-speed rotation (600 rpm or less) (FIG. 14).

First, in step S501, as in step S303 of FIG. 3, it is determined whether a pulse edge has been detected. The detection of the pulse edge is performed, for example, by detecting the rise of a ripple pulse.
If no pulse edge is detected, step S502
To step S if a pulse edge is detected.
Proceed to 503.

In step S502, the operation of the motor is continued. Thereafter, this processing is temporarily ended. Step S
At 503, it is determined whether the cycle of the ripple pulse has exceeded a threshold value (second predetermined value) of 10 ms.
If the cycle is 10 ms or less, the motor is rotating in a rotation range exceeding the extremely low speed rotation, and therefore, step S50 is performed.
Proceed to 2 to continue the operation of the motor. On the other hand, if the period exceeds 10 ms, it can be determined that the motor is rotating at an extremely low speed, and the process proceeds to step S504.

In step S504, it is determined whether or not the power supply voltage is in a sudden fluctuation period (power supply voltage fluctuation detection period shown in FIG. 15). Here, when the drive current becomes equal to or less than the threshold value ei (third predetermined value) (A), it is determined that the power supply voltage is rapidly changed. A certain period after the sudden change is detected is referred to as a “power supply voltage sudden change detection period”. If the determination result in step S504 is YES, that is, if the power supply voltage is not within the rapid fluctuation period, the process proceeds to step S502.
Otherwise, the process proceeds to step S505.

In step S505, the motor is stopped. Thereafter, this processing is temporarily ended. The threshold value ei is a no-load current corresponding to the rotation speed (no-load rotation speed) when the motor is rotating in a no-load state, as shown in FIG. However, in the following description, the drive current is compared with a predetermined threshold value ei (A). However, in practice, a voltage signal having a voltage value proportional to the drive current is converted to a threshold value ei (for example, 1). . 4A).

As described above, in the "motor extremely low speed rotation detection process", only when it is determined in step S503 that the cycle of the ripple pulse has exceeded 10 ms and it is determined that the period is not within the power supply voltage sudden change detection period, It is determined that the motor is rotating at an extremely low speed, and the motor is stopped. On the contrary,
Even if it is determined that the period has exceeded 10 ms, if it is determined that the period is within the power supply voltage sudden change detection period, the motor operation is continued without determining that the motor is rotating at extremely low speed.

Next, a description will be given, with reference to FIG. 13, of the "power supply voltage sudden fluctuation detection processing" executed by the CPU 23.
In step S601, it is determined whether the motor is operating. If the motor is stopped, this process is terminated. If the motor is operating, the process proceeds to step S602.

In step S602, it is determined whether the drive current is less than a predetermined threshold value ei. If the driving current is equal to or larger than the threshold value ei, the process proceeds to step S603. If the driving current is smaller than the threshold value ei, the process proceeds to step S603.
Proceed to 604.

Now, at time t1 shown in FIG. 15, since the large-capacity actuator was simultaneously operated during the operation of the motor, the power supply voltage fluctuated rapidly (see FIGS. 10 and 11).
Consider a case where the drive current has become less than the threshold value ei. At this time, the determination result of step S602 is YES, and the process proceeds to step S604.

In step S604, it is determined that the power supply voltage has fluctuated rapidly, and the power supply voltage fluctuating detection flag is set to "1". After this setting, the process proceeds to step S605. Step S
At 605, the power supply voltage rapid fluctuation period counter value of the power supply voltage rapid fluctuation period counter is set to “0”. After this setting, this process is temporarily terminated.

Thereafter, when the motor is in operation and in step S60
In step 2, it is determined whether the drive current is less than the threshold value ei. As shown in FIG. 15, after the time point t1, while the drive current is less than the threshold value ei, step S
Since the determination result of step 602 is YES, the above-described step S
Steps 604 and S605 are executed, and the power supply voltage rapid change period count value remains at “0”.

When the drive current becomes equal to or larger than the threshold value ei at the time point t2 in FIG. 15, the determination result in the step S602 becomes NO, and the process proceeds to the step S603. Step S6
At 03, it is determined whether the power supply voltage sudden fluctuation detection flag is set to “1”. At this time, since the flag has been set to “1” in step S604, the process proceeds to step S606.

In step S606, it is determined whether the pulse edge detection flag has been set to "1".
If the pulse edge detection flag is set to “0” in step S302 in FIG. 3, step S607
If the flag is set to "1" in step S304, the process proceeds to step S608.

Since the pulse edge has not yet been detected immediately after the time point t2, the determination result in the step S606 is NO, and the process proceeds to a step S607. In step S607, it is determined whether or not the power supply voltage rapid fluctuation period count value has exceeded a predetermined value 10 (a fourth constant period). At the moment, the count value is "0",
The decision result in the step S607 is NO, and this processing is temporarily ended.

Thereafter, at time t3 shown in FIG. 15, and when a pulse edge is detected, step S30 in FIG.
At 4, the pulse edge detection flag is set to "1". Thus, when the process proceeds to step S606, the determination result is YES, and the process proceeds to step S608.

In step S608, the power supply voltage rapid fluctuation period count value is incremented by "1". Thereafter, the process proceeds to step S607. At this time, since the count value is “1”, the determination result of step S607 is NO.
, And this process is temporarily ended.

Thereafter, every time a pulse edge is detected,
In step S608, the power supply voltage rapid fluctuation period count value is incremented by “1”. Now, at the time point t4 shown in FIG. 15, the pulse edge of the tenth ripple pulse from the time point t3 is detected, and the count value becomes "1".
If “0” is exceeded, the determination result of step S607 is YES
, And the process proceeds to step S609.

In step S609, it is determined that the power supply voltage sudden change detection period has ended, and the power supply voltage sudden change detection flag is set to "0". After this setting, the process proceeds to step S610.

In step S610, the power supply voltage rapid fluctuation period count value is set to "0". After this setting, this processing is temporarily ended. As described above, in the process of FIG. 13, the power supply voltage sudden change detection period starts when the drive current becomes less than the threshold value ei due to the sudden change of the power supply voltage (time t1 in FIG. 15). After this start, the drive current becomes the threshold ei.
While the value is less than (until time t2), step S60
At 5, the power supply voltage rapid fluctuation period count value is kept at "0". When the drive current becomes equal to or more than the threshold value ei (t in FIG. 15).
At three times), every time the pulse edge of the ripple pulse is detected, the count value of the power supply voltage rapid change period counter is incremented by “1”. Then, when the count value exceeds “10” (at time t4 in FIG. 15), the power supply voltage sudden change detection period ends.

Note that step S504 in FIG. 12 and step S602 in FIG. 13 each correspond to “power supply voltage sudden fluctuation detecting means”. The second configured as described above
According to the embodiment, the following operation and effect can be obtained.

(N) Steps S503, S504 and S
According to the process of step 505, when there is a sudden change in the power supply voltage, the motor is actually rotating at a rotational speed (a rotational speed higher than 600 rpm) at which a ripple pulse can be normally detected. It is possible to prevent erroneous determination that the rotation is extremely low speed (600 rpm or less). For example,
When the reproduction switch 33 or 34 is operated, it is possible to prevent the motor from being stopped by mistake while the various parts of the sheet are being moved to the storage position.

(G) By the processing of steps S602 and S604, a sudden change in the power supply voltage can be accurately detected by the operation of the large-capacity actuator. (ヲ) During the power supply voltage abrupt fluctuation detection period, even if the determination of the motor extremely low speed rotation is made, the determination can be invalidated and the operation of the motor can be continued (step S in FIG. 12).
504, S502). In this case, during a certain period (period S shown in FIGS. 10 and 11) immediately after the detection of the power supply voltage sudden change,
The drive current temporarily and rapidly drops, and the ripple pulse cannot be detected for a moment, and the motor control based on the pulse is interrupted. However, the interruption occurs for a very short time of about one rotation of the motor. For this reason, the moving amount of each part of the seat that should be originally moved during this period is extremely small, and there is no positional displacement of each part of the seat that is large enough for the occupant to feel uncomfortable.

Next, a position control device according to a third embodiment will be described with reference to FIG. C of the position control device 21
The PU 23 executes the “processing at 100 Hz or less detection”.
First, in step S701, it is determined whether the motor is operating. If the motor is stopped, this process is temporarily terminated. On the other hand, when the motor is operating, the process proceeds to step S702.

In step S702, at the time of starting
Thereafter, it is determined whether or not the detection is performed, that is, whether or not the motor extremely low speed rotation is detected. This determination is made based on whether or not the “determination of 100 Hz or less at startup” is made in step S115 of FIG. 1 and the determination flag for 100 Hz or less at startup is set to “1”. If the flag is not set to “1”, it is determined that there is no detection at 100 Hz or less at the time of startup, and the process proceeds to step S703. On the other hand, if the flag is set to “1” in step S115, it is inverted that detection is performed at 100 Hz or less at startup, and the process proceeds to step S704.

In step S704, it is determined whether a sudden change in the power supply voltage is detected. The determination here is that the power supply voltage is determined to be abruptly changed in step S604 in FIG.
The determination is made based on whether or not the power supply voltage sudden change detection flag is set to “1”. If the flag is set to "1" in step S604, it is determined that a sudden change in the power supply voltage has been detected, and this process is temporarily ended. in this case,
The operation of the motor is continued. On the other hand, if the flag is not set to “1”, it is determined that there is no sudden change in the power supply voltage, and the process proceeds to step S705 to stop the operation of the motor. Thereafter, this processing is temporarily ended.

As described above, steps S701 and S7
02 and S704, even if 100 Hz or less at startup (motor extremely low speed rotation at startup) is detected during motor operation, if a sudden change in power supply voltage is detected, motor operation is started. Is continued. In other words, the motor is stopped only when the frequency of 100 Hz or less is detected at the time of starting and the sudden fluctuation of the power supply voltage is not detected.

In the above step S702, at the time of startup, 100H
If it is determined that there is no detection of z or less, and the process proceeds to step S703, it is determined in step S703 whether or not there is detection in the steady range of 100 Hz or less. The determination here is made based on whether or not “determination of steady-state 100 Hz or less” is made in step S407 of FIG. 4 and the determination flag of steady-state 100 Hz or less is set to “1”. If the flag is not set to “1”, it is determined that there is no detection below the steady range of 100 Hz, and this process is temporarily terminated. On the other hand, when the steady-state region 100 Hz or less determination flag is set to “1”, it is determined that the steady-state region 100 Hz or less is detected, and
The process proceeds to step S704.

At this time, if the power supply voltage sudden change detection flag is set to "1" in step S604, it is determined that there is a sudden change in the power supply voltage, and this processing is temporarily terminated. In this case, the operation of the motor is continued. On the other hand, if this flag is not set to “1”, it is determined that there is no sudden change in the power supply voltage, and the process proceeds to step S605.
Stop the motor.

As described above, steps S701 and S7
02 and S704, even if a steady-state region of 100 Hz or less (motor extremely low-speed rotation in the steady-state region) is detected during the operation of the motor, if a sudden change in the power supply voltage is detected, the operation of the motor is started. Is continued. That is, the motor is stopped only when the steady-state range of 100 Hz or less is detected and the sudden change in the power supply voltage is not detected.

According to the third embodiment configured as described above, the following operation and effect can be obtained. (W) By the processing of steps S702 and S704, it is possible to prevent the motor from being erroneously determined to be rotating at an extremely low speed when the power supply voltage suddenly fluctuates at or immediately after the motor is started.

(F) By the processing in steps S703 and S704, the motor is stopped only when the motor is rotated at an extremely low speed because the motor load increases during operation of the motor.

Next, a position control device according to a fourth embodiment will be described with reference to FIG. In the position control device 21 according to the present embodiment, the extremely low-speed rotation (for example, 100 Hz) is performed in a case where the motor rotation gradually decreases to the extremely low-speed rotation, and in a case where the motor rotation rapidly decreases to the extremely low-speed rotation. Less than)
Is changing the detection method.

First, as a first detection method, a description will be given of a detection method in a case where the motor rotation gradually decreases as shown in FIG. That is, the second
Similarly to the case of the embodiment, when the period of the ripple pulse exceeds a predetermined threshold during the operation of the motor, it is determined that the motor is rotating at a very low speed (100 Hz or less). To detect.

Next, a second detection method will be described. In the first detection method, each part of the sheet driven by the motor hits a stopper or the like at the end of its movable range, so that the motor is locked (motor end point lock), and the motor rotates as shown in FIG. If the motor speed drops rapidly, it is not possible to detect the extremely low speed rotation of the motor. The reason is that the rotation speed of the motor jumps from the region where the normal ripple pulse can be detected by the motor lock to the region where the extremely low-speed rotation is detected by the cycle at a stretch, and is shown in FIGS. 19 (b) and 19 (c). This is because it enters the area where the incorrect pulse shown occurs. In this case, too, it is necessary to detect an extremely low-speed rotation of the motor and to perform appropriate control such as stopping the motor in order to prevent occurrence of a trouble such as each part of the seat being controlled to an incorrect position.

When the motor is locked, a fine reciprocating motion may occur between the motor and a cable connected to the motor due to magnetic resonance. When this occurs, the pulse continues to be generated even though the motor is locked. Therefore, in the case of the above memory sheet, a large shift occurs in the sheet storage position. May be moved to a position significantly deviated from the position.

In order to prevent the occurrence of these problems,
As shown in FIG. 18 (c), when the motor rotation sharply decreases and becomes extremely low speed, the change rate of the drive current (change rate = current / number of ripple pulses) is calculated. Is larger than a predetermined value, it is determined that the motor has rotated to an extremely low speed. That is, when the drive current changes at a certain rate or more, it is determined that the motor is suddenly locked (for example, the motor end point is locked), and the extremely low speed rotation of the motor is detected. This detection makes it possible to perform appropriate control such as stopping the motor. In this manner, a sudden decrease in the motor rotation speed when the motor end point is locked can be detected based on the change rate of the drive current.

According to the fourth embodiment configured as described above, the following operation and effect can be obtained. (G) In the case where the rotation of the motor gradually decreases and becomes extremely low speed, the extremely low speed rotation of the motor can be detected by the first detection method. At the same time, even when the motor rotation suddenly drops at the time of motor lock such as the above-mentioned motor end point lock, appropriate control such as detecting the extremely low speed rotation of the motor and stopping the motor after this detection can be performed. it can. Therefore, in the case of the memory sheet, it is possible to prevent a large shift in the sheet storage position and prevent the sheet sections from being moved to a position significantly shifted from the storage position when the reproduction switch is operated.

The present invention can be embodied with the following modifications. In the first embodiment, the drive current may be amplified inside the ripple pulse detection circuit 50.

In the first embodiment, although the threshold value is set, the power supply voltage bv at the time of steady current may be corrected so as to match the power supply voltage av at the time of inrush current. In the first embodiment, the first period and the second period may be set to different predetermined times without using a ripple pulse.

In the fourth embodiment, the second detection method may be applied to the detection processing at 100 Hz or less shown in FIG. In other words, between step S703 and step S704 in FIG.
A determination process is performed to determine whether or not there is detection of z or less. As a result, as in the case of “100 Hz or less at start-up” or “100 Hz or less in a steady state”, in a state where no sudden change in power supply voltage is detected (NO in step S704), the second detection method is used. The motor can be stopped only when extremely low speed rotation is detected.

The threshold value e in the second embodiment.
i is not limited to the no-load current, and any value may be used as long as it can reliably determine that the motor is operating at extremely low speed in consideration of the above-described variation in the characteristics of the motor.

In the above embodiments, the rotation speed of 600 rpm or less is set as the extremely low speed rotation of the motor. However, an arbitrary speed can be selected in design. -The present invention can be applied to all movable bodies that are positioned and driven by a motor, such as opening and closing bodies such as a power window and a sunroof, in addition to the memory sheet.

[0122]

As described above, according to the first aspect of the present invention, an extremely low-speed rotation can be detected even when the motor starts to rotate at an extremely low speed. Further, it is possible to prevent the extremely low-speed rotation of the motor from being erroneously detected in the rotation range where the ripple pulse can be detected.

According to the fifth aspect of the present invention, it is possible to prevent the extremely low-speed rotation of the motor from being erroneously detected even when the driving current of the motor decreases when the large-capacity actuators are simultaneously operated.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a detection process at 100 Hz or less at startup according to a first embodiment.

FIG. 2 is a flowchart showing a ripple pulse count process according to the embodiment;

FIG. 3 is a flowchart showing a pulse edge detection process according to the embodiment;

FIG. 4 is a flowchart showing a detection process in a constant range of 100 Hz or less according to the embodiment;

FIG. 5 is an exemplary block diagram showing the entire configuration of the position control device according to the embodiment;

FIG. 6 is a configuration diagram showing a part of the ripple pulse detection circuit shown in FIG. 5;

FIG. 7 is an explanatory diagram showing a starting current waveform of the embodiment.

FIG. 8A is a waveform chart showing a drive current at a low load.
(B) A waveform diagram showing a drive current under a high load.

FIG. 9 is an explanatory diagram showing characteristics of a DC brush motor.

FIG. 10 is an explanatory diagram showing a current waveform at the time of a sudden change in power supply voltage according to the second embodiment.

FIG. 11 is an explanatory diagram showing a current waveform similar to FIG.

FIG. 12 is a flowchart illustrating motor extremely low speed rotation detection processing according to the second embodiment.

FIG. 13 is a flowchart showing a power supply voltage sudden change detection process according to the embodiment;

FIG. 14 is an explanatory diagram illustrating a cycle of a ripple pulse detected in the embodiment.

FIG. 15 is an explanatory diagram of a power supply voltage fluctuation period according to the embodiment.

FIG. 16 is an explanatory diagram showing motor characteristics of the embodiment.

FIG. 17 is a flowchart illustrating processing at the time of detection of 100 Hz or less according to the third embodiment.

FIG. 18 is a waveform chart showing a detection method of the position control device according to the fourth embodiment.

FIG. 19 is a waveform chart showing a relationship between a ripple pulse and a motor rotation speed.

[Explanation of symbols]

21 ... Position control device, 22 ... Electronic control unit, 23 ...
CPU as control means, 39 to 42 ... motor, 50 ...
Ripple pulse detection circuit.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideyuki Kanie 2-1-1 Asahimachi, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. F-term (reference) 5H550 AA16 BB08 DD06 EE01 GG05 HB14 JJ04 LL13 LL14 LL15 LL22 LL23 5H571 AA03 BB07 EE02 FF01 FF07 GG04 JJ04 LL14 LL15 LL22 LL23

Claims (5)

[Claims] 1. A current detecting means for detecting a driving current of a motor, a pulse detecting means for outputting a ripple pulse obtained by pulsing a ripple component included in the driving current, and controlling the driving of the motor based on the ripple pulse. A control unit that calculates a difference between the inrush current at the time of starting the motor and the steady-state current detected by the current detection unit, and the difference is smaller than a first predetermined value. A controller for determining that the motor is rotating at an extremely low speed equal to or lower than a predetermined number of rotations. 2. The motor control according to claim 1, wherein the control unit sets the predetermined value based on a power supply voltage at the time of the inrush current and a power supply voltage at the time of the steady current. apparatus. 3. The control means includes a period setting means for setting a first fixed period from the start of the motor until the drive current is stabilized, and detects an extremely low speed rotation of the motor only within the fixed period. The motor control device according to claim 1 or 2, wherein: 4. The motor control device according to claim 1, wherein the control means is configured to perform a second
Wherein the maximum current of the drive current within the predetermined period is defined as the inrush current, and the current when the drive current is stabilized within the third predetermined period after the lapse of the second predetermined period is defined as the steady-state current. The motor control device according to any one of claims 1 to 3, wherein 5. A current detecting means for detecting a driving current of a motor, a pulse detecting means for outputting a ripple pulse obtained by pulsing a ripple component included in the driving current, and controlling the driving of the motor based on the ripple pulse. The control device, comprising: a controller that, when the cycle of the ripple pulse exceeds a second predetermined value, determines that the motor is rotating at an extremely low speed equal to or lower than a predetermined number of revolutions; When the current falls below the third predetermined value, the fourth
A motor control device, wherein the determination is invalidated within a certain period of time.