JP2010187507A - Motor control device - Google Patents

Abstract

Provided is a motor control device that can detect an extremely low-speed rotation state of a motor with high accuracy even under various environments.
A control device includes a current detection unit that detects a current of a motor, a pulse detection unit that outputs a ripple pulse, and a control unit that controls driving of the motor based on the ripple pulse. The device 21 has a filter means 10 for passing the frequency components from the frequency f1 to the frequency f2 from the motor current, and the inrush current value of the motor current based on the time point when the maximum current value of the motor current of the passed frequency component is detected. Derived calculation unit 11, inrush current value, and time when motor drive is stabilized in the interval from the start of the motor after rush current value derivation until the count value of the ripple pulse counted from the time of reaching the predetermined value to the extremely low speed rotation determination time A storage unit 12 for storing a steady current value, which is a motor current value in the motor, and a difference between the inrush current value and the steady current value is calculated, and the magnitude of the difference is calculated. And a determination means 13 a very low rotational speed over data.
[Selection] Figure 2

Description

  The present invention relates to a motor control device that moves a movable body of an in-vehicle functional component such as a memory sheet, a power window, and a sunroof.

  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 the regeneration switch is pushed, and then the seat is automatically stored at the stored position. The memory sheet to be set is used. The memory seat is provided with a slide motor that moves the entire seat back and forth, a reclining motor that tilts the seat back back and forth, and the like. By driving these motors by operating the operation switches, the sheet position can be adjusted to a desired position, and the sheet position can be stored by the storage switch. For sheet position control and status memory, ripple components included in the motor current of the DC motor that drives the sheet are detected as ripple pulses synchronized with the motor via a pulse generation circuit using a differentiation circuit, Based on. At that time, when the current position of the seat is at the front end or the rear end on the seat rail, the motor has a very low speed (for example, the frequency of the ripple pulse is 100 Hz or less and the speed is 600 rpm or less), Control is performed while simultaneously determining whether or not to stop the operation of the motor. For example, in the prior art disclosed in Patent Document 1, in order to determine whether or not the motor is rotating at an extremely low speed, the motor current from the start of the motor to the first predetermined period (1 to A1 pulse) as shown in FIG. Is the inrush current (aiMAX). Then, the ratio of the current current value to the current power supply voltage (current current value / current power supply voltage value) is updated before the first predetermined period and up to the second predetermined period (A1 + 1 to B pulses). If the current value is larger than the previous value, the current value is updated as a steady current (biMAX), and after a second predetermined period, the speed is extremely low depending on the difference between the inrush current and the steady current (aiMAX−biMAX). Judging the rotation state.

JP 2002-325475 A

  However, in the conventional method, in order to determine the extremely low speed rotation state, the maximum current value in the first predetermined period (1 to A1 pulse) set in advance is used as the inrush current value. Therefore, as shown in FIG. 10, when the load increases after starting the motor, the current value exceeding the original inrush current value to be detected is set as the inrush current value depending on the constant of the set A1 pulse and the output timing of the pulse. Resulting in. Therefore, the extremely low speed rotation state of the motor determined by the difference between the inrush current value and the steady current value (aiMAX−biMAX) may not be correctly determined. Also, as shown in FIG. 11, if the setting of the constant of the A1 pulse is shortened and made small in order to prevent the detection of the inrush current value from being delayed, the timing at which the first pulse is output is not constant, so that the current value reaches the peak. In some cases, the predetermined period may be exceeded before. Therefore, it may be set lower than the inrush current value that should be detected and difficult to determine correctly. In order to respond to the above, a section (1 to A1 pulse which is the “first predetermined period” in the prior art) that can cope with current waveforms in various situations such as mechanical variation, low temperature, and aging deterioration is set. However, since the pulse output timing varies, there is a case where the inrush current value cannot be detected correctly and the detection of the extremely low speed rotation state is erroneously determined. As a result, a significant shift occurs in the sheet storage position, and there is a possibility that each part of the sheet may be moved to a position greatly shifted from the storage position when the reproduction switch is operated.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and provides a motor control device that can detect an extremely low-speed rotation state of a motor with high accuracy even under various environments with a simple configuration. It is.

  In order to solve the above problems, the features of the invention according to claim 1 are: current detection means for detecting a motor current; pulse detection means for outputting a ripple pulse obtained by pulsing a ripple component included in the motor current; And a control unit that controls the driving of the motor based on the ripple pulse. The control unit further includes a band-pass filter that starts computation immediately after the motor is started. Filter means for passing frequency components from frequency f1 to frequency f2 among frequency components, and the inrush current of the motor current based on the time point when the maximum current value of the motor current of the frequency component that has passed through the filter means is detected A calculation unit for deriving a value, the inrush current value derived by the calculation unit, and after the inrush current value is derived, A memory that stores a steady current value that is the motor current value at the time when the motor drive is stabilized in the interval from the start of the motor to the extremely low speed rotation determination time when the counted value of the ripple pulse reaches a predetermined value. And a determination means for calculating a difference between the inrush current value and the steady current value and determining an extremely low speed rotation of the motor from the magnitude of the difference.

  According to a second aspect of the present invention, in the first aspect of the present invention, the motor current value is obtained by combining the motor current values at least at one measurement point before and after the detection time of the inrush current value derived by the calculation unit. The maximum value among the acquired inrush current value and at least one motor current value at the front and rear is the inrush current value.

  According to the first aspect of the present invention, the inrush current can be detected by detecting the high frequency component included in the motor current of the motor. As a result, it is only necessary to search for the inrush current from the time of start-up to the determination point of the extremely low speed rotation state. Therefore, the interval in which the maximum current value performed in the prior art is detected as the inrush current (in the present invention, 1 to a pulse). (Strict interval a) is not necessary (it is sufficient to set the constant a so that an inrush current always exists). Further, even when the load increases immediately after startup and the current value continues to increase, the inrush current can be detected with high accuracy because the high frequency component included only in the inrush current is detected and determined.

  According to the second aspect of the present invention, on the basis of the time point when the frequency component becomes maximum in the current value after the bandpass filter processing, the motor current value at the same point and the motor current value at least one point before and after are the largest. The motor current value is used as the inrush current. As a result, the inrush current can be detected with higher accuracy even when the inrush current does not match the maximum motor current timing derived after the bandpass filter processing due to sampling timing or some characteristic variation of the actual machine. I can do it.

It is a block diagram which shows the whole structure of the position control apparatus which concerns on this embodiment. It is the flowchart 1 which shows a 100Hz or less detection process at the time of starting concerning 1st Embodiment. It is a block diagram of the band pass filter which concerns on this embodiment. It is a motor current graph (a figure) at the time of a motor steady operation for effect verification, and a motor current graph (b figure) after a band pass filter process. It is a motor current graph (a figure) at the time of motor high load operation | movement, and a motor current graph (b figure) after a band pass filter process. It is the flowchart 2 which shows a 100Hz or less detection process at the time of starting concerning 2nd Embodiment. It is a motor current graph (a figure) at the time of motor high load operation concerning a 2nd embodiment, and a motor current graph (b figure) after a band pass filter process. It is a wave form diagram which shows the relationship between the ripple pulse which concerns on this embodiment, and a motor current. It is a wave form diagram which shows the relationship between the ripple pulse and motor current in a prior art. It is a motor current graph at the time of the motor high load operation | movement in a prior art. It is a motor current graph at the time of the motor steady operation in a prior art.

  Hereinafter, a motor control device according to the present invention will be described in a first embodiment applied to a memory seat device mounted on a vehicle. FIG. 1 schematically shows the overall configuration of a control device 21 that controls the position of each part (movable body) of the memory sheet device. The control device 21 includes an electronic control unit (hereinafter referred to as “ECU”) 22 formed of a microcomputer.

  The ECU 22 includes a CPU 23 as control means, a ROM, a RAM, a backup RAM, etc., not shown. The ROM is a memory that stores various control programs, maps that are referred to when these programs are executed, and the like. The CPU 23 executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory that temporarily stores calculation results in the CPU 23, data input from the outside, and the like, and the backup RAM is a nonvolatile memory that stores the stored data and the like. The CPU 23, the ROM, the RAM, and the backup RAM are connected to each other via a bus (not shown), and are connected to the input interface circuit 24 and an output interface circuit (not shown).

  The ECU 22 pulsates the ripple component included in the motor current flowing through each of the motors 39 to 42 and outputs a ripple pulse synchronized with each motor, and amplifies the motor current. An amplifier circuit 51 is provided.

  The ripple pulse detection circuit 50 is configured such that the motor current is converted into a signal having a voltage value proportional to the current value by the resistor 52 and input as a motor rotation signal. Note that the specific configuration of the ripple pulse detection circuit 50 is disclosed in Japanese Patent Application Laid-Open No. 2002-325475, and a description thereof will be omitted. Then, a ripple pulse having a frequency in accordance with the rotation speed of each of the motors 39 to 42 detected by the ripple pulse detection circuit 50 is output to the CPU 23 via the output interface circuit, and the output ripple pulse is output. The position is detected and controlled based on the count value.

  The motor current amplified by the amplifier circuit 51 is A / D converted by an A / D converter provided in the ECU 22 and read into the CPU 23. Thus, the CPU 23 constantly detects the motor currents of the motors 39 to 42. The amplifying circuit 51 and the A / D converter constitute current detecting means for detecting the motor current.

  A battery (BAT) 26 is connected to the CPU 23 via a power 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.

  An operation switch 28 for adjusting the position (sheet state) of each part of the sheet is connected to the input interface circuit 24 of the CPU 23. The operation switch 28 includes slide switches 29a and 29b, reclining switches 30a and 30b, front vertical switches 31a and 31b, and lifter switches 32a and 32b.

  In addition to the operation switch 28, memory playback 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 sheet can be adjusted to a desired sheet position (sheet state). When storing the adjusted sheet position in a memory (for example, the RAM), one of the reproduction switches 33 and 34 is pressed together with the storage switch 35. Thereafter, when any one of the reproduction switches 33 and 34 is pressed, each part of the sheet is automatically moved to the stored sheet position.

  Four motors 39 to 42 are connected to the output interface circuit of the CPU 23 via a relay group 43. These motors are direct current 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 the 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 the set of coils corresponding to the operated switch. Thereby, the switching terminals of the relays of the same group are switched, and the motors corresponding to the relays of the same group among the motors 39 to 42 are independently driven 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 rotates forward or reverse by operating the reclining switches 30a and 30b to tilt the seat back forward / backward. The front vertical motor 41 rotates forward or reverse by operating the front vertical switches 31a and 31b to raise / lower the front portion of the seat cushion. The lifter motor 42 rotates forward or reverse by operating the lifter switches 32a and 32b to raise / lower the rear part of the seat cushion.

  Further, the ECU 22 detects the inrush current value ai_MAX shown in FIG. 8 with high accuracy even when the load increases for some reason after the motor is started and the motor current value continues to rise (see FIG. 10). A band-pass filter 10 as a filter means for passing a current ai_flt of a predetermined frequency component of the motor current, and an operation for deriving an inrush current value ai_MAX on the basis of the time point when the maximum current value ai_flt_MAX in the current ai_flt is detected Part 11 is provided. Further, a storage unit 12 including a RAM that stores the derived inrush current value ai_MAX and the steady current value bi_MAX that is the motor current value at the time when the motor drive detected after the inrush current value ai_MAX is derived most stably. And are provided. Then, the difference between the inrush current value ai_MAX and the steady current value bi_MAX stored in the storage unit 12 is calculated, and when the difference is smaller than the predetermined value, it is determined that the motor is locked or the rotation is extremely low speed less than the predetermined rotation speed. Judgment means 13 is provided.

  Here, the inrush current value ai_MAX is the maximum current value in the motor current that suddenly increases immediately after startup and settles to a steady value during normal operation of the motor, and is almost unaffected by the motor load. It has a certain characteristic.

  As shown in FIG. 3, the band-pass filter 10 includes a high-pass filter HPF having a frequency f1 as a cutoff frequency and a low-pass filter LPF having a frequency f2 that is higher than the frequency f1 as a cutoff frequency. The motor current passes through the amplifier circuit 51 and is amplified and then input to the bandpass filter 10. The motor current passes through the high-pass filter HPF and the low-pass filter LPF, is processed, and is A / D converted by the A / D converter. Then, the current ai_flt of the frequency components f1 to f2 is input to the CPU 23 as digital data. The bandpass filter 10 is activated immediately after the motor is activated.

  The current ai_flt of the frequency components f1 to f2 after the filter processing is a relatively high frequency component in the motor current components. The present invention aims to detect the inrush current value ai_MAX using the high-frequency component current ai_flt. That is, it is predicted that the characteristic of the high frequency component generated only when a sudden change occurs is in good agreement with the characteristic of the inrush current value ai_MAX. Therefore, the maximum value ai_flt_MAX of the filtered current ai_flt is first detected, and the value of the motor current at the time (timing) when the maximum value ai_flt_MAX is detected is set as the inrush current value ai_MAX.

  FIG. 4 shows the verification result of the inference performed by the inventor. FIG. 4A shows actually measured motor current during steady operation, and FIG. 4B shows data of current ai_flt after the band-pass filter 10 processing. The result shows that the detection timing of the maximum value ai_flt_MAX of the filtered current ai_flt shown in FIG. 4B and the detection timing of the inrush current value ai_MAX generated in the motor current shown in FIG. You can see that they match very well. Therefore, it was confirmed that the inrush current value ai_MAX can be obtained by detecting the maximum value ai_flt_MAX of the current ai_flt obtained by the filtering process and obtaining the motor current value at the detection timing. Thus, for example, as shown in FIG. 5 (a), even when the load increases after the motor is started and the motor current value continues to increase, the maximum value ai_flt_MAX of the current ai_flt after the filtering process as shown in FIG. 5 (b). Inrush current value ai_MAX shown in FIG. 5A can be detected with high accuracy. The inventor has found this knowledge from the fact that when the frequency component of the current value is analyzed, the frequency component in the predetermined frequency range is included at a high timing at the time when it is desired to detect it as the inrush current. However, since incorporating frequency analysis into a motor control device is problematic in terms of cost, a bandpass filter is employed in the present application. The cut-off frequencies f1 and f2 of the bandpass filter 10 are values that are adapted in advance for each system so that the inrush current value ai_MAX can be detected with the highest accuracy.

  As shown in FIG. 1, the calculation unit 11 is provided in the CPU 23 and is configured to be started immediately after the motor is started and to repeat the calculation at predetermined intervals (for example, every 2 ms). The calculation unit 11 periodically reads and stores the current ai_flt after the processing of the bandpass filter 10 together with the power supply voltage av at the time of measurement (current). The maximum value of the read current ai_flt is searched and detected as the inrush current value ai_MAX from the ripple pulse count value 1 to a pulse immediately after the motor start shown in FIG. Here, the ripple pulse count value a pulse is a predetermined interval that is expected to include the maximum value ai_flt_MAX and does not need to be a strict value but is an approximate value (approximate value). And after that, the search is continued until the ripple pulse count value c pulse described later, and if the value of the current ai_flt larger than the inrush current value ai_MAX detected between 1 and a pulses is detected, it was detected. The value is updated as the inrush current value ai_MAX. The ripple pulse count value c is a ripple pulse count value counted immediately after the start of the motor, which is determined by evaluation in advance in order to reliably detect the steady current value bi_MAX. The number of pulses between the ripple pulse count value a and the ripple pulse count value c is defined as a ripple pulse count value b. That is, there is a relationship of c pulse = a pulse + b pulse.

  The steady-state current value bi_MAX is a section in which the count value of the ripple pulse counted after the start of the motor detected after the inrush current value ai_MAX is derived reaches a predetermined value c pulse, that is, a section until the extremely low speed rotation determination time. This is the motor current value when the motor drive is most stable. The method is to determine the ratio between the current motor current value and the current power supply voltage (current motor current value / current power supply voltage value), and the ratio between the previous motor current value and the power supply voltage value that has been updated before the present (bi). The reciprocal of the resistance value (ease of current flow) / bv (previous power supply voltage value)) is compared, and if the ratio value measured last time is larger, Is determined to be stable, and the steady current value bi_MAX and the power supply voltage bv are kept at the previous values. On the other hand, if the ratio value measured this time is larger, it is determined that the motor drive is more stable at the present time, the current motor current value is set to the steady current value (bi_MAX), and the current power supply voltage is determined. Each value is updated as the power supply voltage value bv. Then, the inrush current value ai_MAX and the steady current value bi_MAX are stored in the storage unit 12 composed of RAM.

  The determination means 13 is provided in the CPU 23 of FIG. First, the determination unit 13 calculates the difference between the inrush current value ai_MAX and the steady current value bi_MAX stored in the storage unit 12. When the difference is smaller than a predetermined threshold value read from a map stored in the ROM in advance, it is determined that the motor is in a very low speed rotation state equal to or lower than a predetermined rotation speed. The map is a data group acquired in advance, and the reference value (inrush current value ai_MAX−steady state) corresponding to the power supply voltage av at the time of inrush current value ai_MAX measurement and the power supply voltage bv at the time of measurement of the steady current value bi_MAX, which fluctuate due to various causes. Current value bi_MAX), and the reference value is used as a threshold value.

  Next, processing executed by the CPU 23 will be described with reference to the flowchart 1 shown in FIG. These processes are executed at predetermined control cycles, for example, every 2 ms. In addition, since these processes are similarly performed for the four motors 39 to 42, only one of the motors will be described without reference numerals in the following description.

  First, in step S101, it is determined whether or not the motor is operating. When the motor is stopped, the process of FIG. If the motor is operating, the process proceeds to step S102.

  In step S102, it is determined whether or not the pulse count value of the ripple pulse counter is greater than a predetermined value c (= a + b). If the count value is less than or equal to c, the process proceeds to step S103. If the count value exceeds the predetermined value c, the process of FIG. That is, in step S102, it is determined whether or not the search interval for the ripple pulse count value for the steady current value bi_MAX has ended.

  Next, in step S103, it is determined whether or not the pulse count value is a predetermined value c. If the pulse count value is the predetermined value c, the search section for the steady current value bi_MAX is completed, and the process proceeds to step S115 described later, and is smaller than the predetermined value c. If it is a value, the process proceeds to step S104.

  In step S104, the filtered current passed by the bandpass filter 10 is read and set as the processed current ai_flt.

  In step S105, it is determined whether or not the current calculation is the first time. If it is the first time, the process proceeds to step S107. If it is the second time or later, the process proceeds to step S106.

  In step S106, the current filtered current ai_flt value is compared with the previously obtained filtered maximum current value ai_flt_MAX. If the current current ai_flt is greater, steps S107 to S109 are sequentially executed. Is done. On the other hand, when the current current ai_flt is less than or equal to the maximum current value ai_flt_MAX, the process proceeds to step S110.

  In step S107, the current filtered current ai_flt value is set as the filtered maximum current value ai_flt_MAX.

  In step S108, the current motor current read value (current motor current value) input from the amplifier circuit 51 via the A / D converter is set as the inrush current value ai_MAX.

  In step S109, the read value (current power supply voltage value) of the battery 26 at the time of reading the current motor current value set as the inrush current value ai_MAX in step S108 is set as the power supply voltage value av of the inrush current ai_MAX. To do.

  In step S110, it is determined whether or not the ripple pulse count value immediately after the start of the motor is a or less, and steps S101 to S109 are repeatedly executed until the pulse count value becomes greater than a. When the pulse count value becomes larger than a, the process proceeds to step S111.

  In step S111, it is determined whether or not the ripple pulse count value has advanced by one pulse from a (a + 1). If the current time is immediately after exceeding a, the pulse count value is (a + 1), so the process proceeds to step S113. If the pulse count value is greater than a + 1, the process proceeds to step S112.

  In step S112, the ratio of the current motor current value to the current power supply voltage value (current motor current value / current power supply voltage value) is set to bi_MAX (previous value of steady current) and bv (power supply value) set in steps S113 and S114, respectively. It is determined whether or not it is larger than the ratio (bi_MAX / bv) of the previous voltage value. When this determination result is NO, that is, when the change rate of the motor current with respect to the change in the power supply voltage is smaller than the previous change rate, it can be determined that the motor has shifted to the steady rotation, and the processing of FIG. Once terminated. If the determination result is YES, that is, if the change rate of the motor current with respect to the change of the power supply voltage is larger than the previous change rate, it can be determined that the motor has not yet shifted to the steady rotation, and the above step Steps S113 and S114 are executed to update bi_MAX and bv with the current motor current value and the current power supply voltage value, respectively.

  In step S113, the current motor current read value (current motor current value) input from the amplifier circuit 51 via the A / D converter is set as the maximum value (bi_MAX) of the steady current bi.

  In step S114, the read value of the power supply voltage (current power supply voltage value) at the time when the motor current (steady current bi) set as bi_MAX in step S113 is read is set as the power supply voltage value bv in the steady current. After this setting, the processing in FIG. 2 is temporarily terminated.

  Thereafter, step S112 is executed until the pulse count value becomes equal to c (= a + b) in step S103. Then, until the current value of the change rate becomes equal to or less than the previous value (until both change rates match), the steps S113 and S114 are executed, and bi_MAX and bv are updated.

  When the pulse count value becomes equal to c (= a + b), the determination result in step S103 is YES, and the process proceeds to step S115. In step S115, the map stored in the ROM is searched based on the values of av and bv set in steps S109 and S114, and compared with the difference between ai_MAX and bi_MAX (difference between the inrush current and the steady current). Set the threshold value. Thereafter, (ai_MAX−bi_MAX) is calculated, and the process proceeds to step S116.

  In step S116, it is determined whether or not the current difference (ai_MAX−bi_MAX) is less than the threshold value. If the current difference is greater than or equal to the threshold value, it can be determined that the motor is rotating at a rotation speed (over a very low speed rotation, for example, a rotation speed of 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 less than the threshold value, the process proceeds to step S117.

  In step S117, it is determined that the motor is rotating at a rotation speed (the rotation speed is a very low speed rotation or less, for example, a rotation speed of 600 rpm or less including the locked state) at which the frequency of the ripple pulse is 100 Hz or less at the start, and this processing is temporarily terminated Is done.

  If it is determined in step S117 that the rotation speed is 100 Hz or less indicating the extremely low speed, the motor is stopped, or in the case of a memory sheet, control for clearing the sheet position information stored in the memory can be performed. Is possible.

  As apparent from the above description, in the first embodiment, the inrush current value ai_MAX can be detected by detecting the maximum value ai_flt_MAX of the high-frequency component current ai_flt included in the motor current. As a result, it proceeds from the start of the motor to the ripple pulse count value c, and it is sufficient to search for the inrush current ai_MAX until the determination point of the extremely low speed rotation state. Therefore, the maximum value of the current performed in the prior art is detected as the inrush current ai_MAX. Strict setting of the interval (1 to A1 pulse) to be performed is not necessary, and the control can be simplified. In addition, even when the load increases immediately after startup and the motor current value continues to increase, the inrush current value is detected by detecting the current maximum value ai_flt_MAX of the high frequency component that is not easily affected by the load included only in the inrush current ai_MAX. Since ai_MAX is obtained and determined, it is possible to accurately determine extremely low speed rotation.

  Next, a second embodiment will be described. The second embodiment differs from the first embodiment only in the method of setting the inrush current value ai_MAX, and the other configurations are the same, so only the changes are described and the other descriptions are omitted.

  In the first embodiment, in order to set the inrush current value ai_MAX, a detection time point (timing) of the maximum value ai_flt_MAX is obtained from the current value ai_flt after the processing of the bandpass filter 10, and the motor current value at the timing is determined as the inrush current value. ai_MAX. However, in the second embodiment, as shown in FIG. 7B, which is a current value ai_flt graph after the processing of the bandpass filter 10, the detection timing at which the current value ai_flt becomes the maximum value ai_flt_MAX is first used as a reference. Next, the value of the motor current value (see FIG. 7A) at the same timing as the reference is set to ai_1, for example. The motor current values at at least one sampling point before and after ai_1 (a total of three points) are ai_2 and ai_3, and the largest motor current value among ai_1, ai_2, and ai_3 is the inrush current value ai_MAX (FIG. 7). (See (a)). In the example shown in FIG. 7A, ai_2 is adopted as the inrush current. The procedure for determining the extremely low speed rotation of the motor after determining the inrush current value ai_MAX is the same as in the first embodiment.

  Next, processing executed by the CPU 23 in the second embodiment will be described based on the flowchart 2 shown in FIG. First, steps S121 to S127 are the same as steps S101 to S107 in the flowchart 1 of the first embodiment.

  Next, in step S128 corresponding to step S108 in the flowchart 1, the current motor current read value (current motor current value) input from the amplifier circuit 51 via the A / D converter is stored as ai_1. That is, the inrush current value ai_MAX is not set in step S128. The setting of the power supply voltage value av corresponding to step S109 in the flowchart 1 is performed in step S137 described later.

  Steps S129 to S133 are the same as steps S110 to S114 in the flowchart 1.

  Thereafter, when the pulse count value becomes equal to c (= a + b) in step S123, the determination result in step S123 is YES, and the process proceeds to step S134.

  In step S134, the motor current value at the time point one pulse before ai_1 stored in step S128 is read from the stored ai_flt and stored as ai_2. In step S135, the motor current value at the time one pulse after ai_1 is read from the stored ai_flt and stored as ai_3.

  In step S136, the maximum value among the stored ai_1, ai_2, and ai_3 is set as the inrush current value ai_MAX.

  Then, the read value (current power supply voltage value) of the power supply voltage of the battery 26 at the time when any one of the motor current values ai_1, ai_2, or ai_3 set as the inrush current value ai_MAX in step S137 is read is the inrush current value ai_MAX. Is set as the power supply voltage value av.

  Thereafter, as in steps S115 to S117 in the flowchart 1 of the first embodiment, in step S138, the map stored in the ROM is searched based on the values of av and bv set in steps S137 and S133. Then, a threshold for comparison with the difference between ai_MAX and bi_MAX (difference between the inrush current and the steady current) is set. Then, (ai_MAX−bi_MAX) is calculated, and the process proceeds to steps S139 and S140, where the rotational speed at which the frequency of the ripple pulse becomes 100 Hz or less when the motor is started (less than extremely low speed rotation, for example, 600 rpm or less including the locked state). It is determined whether or not it is rotating.

  As is clear from the above description, in the second embodiment, the detection timing of the maximum current value ai_flt_MAX derived after the processing of the bandpass filter 10 and the inrush current value ai_MAX are determined depending on the sampling timing or some characteristic variation of the actual machine. Even when the detection timing does not coincide with the detection timing, the correction can be made, so that the inrush current value ai_MAX can be detected with higher accuracy, and the extremely low speed rotation can be accurately determined.

  In the second embodiment, the inrush current value ai_MAX is searched for at three points of the detection timing of the maximum current value ai_flt_MAX and one point before and after that, but depending on the interval of calculation (measurement) sampling, the number of points to be compared is determined. The number may be increased and compared by a total of 5 points, 2 points before and 2 points behind. Thereby, the inrush current value ai_MAX can be detected with higher accuracy.

  In the first and second embodiments, since it is possible to accurately determine the extremely low speed rotation, in the case of the above memory sheet, there is a significant shift in the sheet storage position, and when the playback switch is operated, the sheet It is possible to prevent each part from being moved to a position greatly deviated from the storage position.

  In the first and second embodiments, in order to detect the inrush current value ai_MAX, the maximum value ai_flt_MAX of the current ai_flt after the processing of the bandpass filter 10 is detected. However, since the current ai_flt after the filter processing becomes maximum immediately after starting the motor, the maximum value of the current ai_flt is not detected, but the timing at which the slope of the ai_flt becomes 0 (the differential value is 0). It is good also as a standard.

  In the first and second embodiments, the band-pass filter processing is performed by an analog circuit, and is input to the CPU 23 through A / D conversion. The digital filter processing may be performed.

  Furthermore, the present invention can be applied to all movable bodies that are positioned and driven by a motor, such as power windows and open / close bodies such as sunroofs, in addition to memory sheets.

DESCRIPTION OF SYMBOLS 10 ... Band-pass filter, 11 ... Operation part, 12 ... Memory | storage part, 13 ... Determination means, 21 ... Control apparatus, 22 ... Electronic control unit (ECU), 23 ... Control means (CPU), 24 ... Input interface circuit, 25 DESCRIPTION OF SYMBOLS ... Power supply circuit, 39-42 ... Motor, 50 ... Pulse detection means (ripple pulse detection circuit), 51 ... Amplifier circuit, 53 ... Ripple pulse shaping circuit.

Claims (2)

Current detection means for detecting the current of the motor;
Pulse detection means for outputting a ripple pulse obtained by pulsing the ripple component included in the motor current;
In a control device comprising control means for controlling the drive of the motor based on the ripple pulse,
The control device further includes a filter unit that allows a frequency component from a frequency f1 to a frequency f2 to pass through a frequency component of the motor current by a band-pass filter that starts calculation immediately after the motor is started.
A calculation unit for deriving an inrush current value of the motor current based on a time point when the maximum current value of the motor current of the frequency component that has passed through the filter means is detected;
After the inrush current value derived by the calculation unit and the inrush current value are derived, the extremely low speed rotation determination point in time when the count value of the ripple pulse counted from the time of starting the motor has reached a predetermined value is obtained. A storage unit that stores a steady current value that is the motor current value at the time when the motor drive is stabilized in the section;
A motor control apparatus comprising: a determination unit that calculates a difference between the inrush current value and the steady current value, and determines a very low speed rotation of the motor from the magnitude of the difference.   2. The acquired inrush current value and at least about the obtained inrush current value according to claim 1, wherein the motor current values at least at one measurement point before and after the detected inrush current value derived by the arithmetic unit are centered. A motor control device characterized in that a maximum value among the motor current values at one point is an inrush current value.

Images