JP2019187233A - Motor control device and control method thereof - Google Patents

Abstract

To shorten the start-up time while achieving stable motor control.SOLUTION: A motor control device for controlling a motor includes detection means for detecting a current flowing through the motor, an estimation means for estimating a rotation speed of the motor from the current detected by the detection means, first drive means for driving the motor by forced commutation control, and second drive means for driving the motor by vector control on the basis of the rotation speed of the motor estimated by the estimation means. Regarding the execution frequency of detection by the detection means and estimation by the estimation means, control is made so that the first execution frequency in a second period after switching from driving by the first drive means to driving by the second driving means is higher than the second execution frequency in a third period following the second period.SELECTED DRAWING: Figure 1

Description

  The present invention relates to motor control.

  A laser beam printer uses a brushless DC motor or the like for driving a photosensitive drum or a transfer belt. Generally, a brushless DC motor has a three-phase stator of U phase, V phase, and W phase, and the motor is rotated by controlling the voltage applied to these. At this time, the rotational speed which changes according to load etc. is detected, and the stable rotational speed is implement | achieved by feeding back to control.

  Conventionally, the rotational speed was measured using a Hall sensor, etc., but in recent years, a method (sensorless vector control) in which the rotational speed is estimated from three-phase current values without using a sensor and vector control is widely used. (For example, Patent Document 1). However, in order to estimate the rotational speed without a sensor, the motor needs to rotate at a certain high rotational speed to generate a sufficient induced current. Therefore, during the period from the start to the time when the rotational speed increases to some extent, a method (forced commutation mode) in which the motor is forcibly rotated by commutation (operation of applying a voltage to each stator to create a rotating magnetic field) is used. (For example, Patent Document 2). Then, after the motor reaches a certain high rotational speed, the forced commutation mode is switched to vector control.

JP2015-213398A Japanese Patent Laid-Open No. 2006-181945

  However, the forced commutation control is a method in which a voltage is applied to each phase of the motor by open loop control, and as a result, it is not preferable from the viewpoint of power efficiency that the current consumption is large and it is used for a long time. Therefore, at the time of start-up, it is desirable to switch from forced commutation control to SFOC with high power efficiency at an early stage. However, immediately after switching from forced commutation control to SFOC, there is generally a problem that a speed estimation error is large, and it takes time until the motor speed converges stably.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a technique capable of shortening the startup time while realizing stable motor control.

In order to solve the above-described problems, a motor control device according to the present invention has the following configuration. That is, the motor control device that controls the motor
Detecting means for detecting a current flowing through the motor;
Estimating means for estimating the rotational speed of the motor from the current detected by the detecting means;
First driving means for driving the motor by forced commutation control;
Second driving means for driving the motor by vector control based on the rotational speed of the motor estimated by the estimating means;
Control is performed so that the motor is driven by the first driving means until the first period from the start of control of the motor, and the second driving means is provided after the first period has elapsed. First control means for controlling the motor to be driven by:
Second control means for controlling the execution frequency of the detection means and the estimation means;
Have
The second control means has a second period after switching from driving by the first driving means to driving by the second driving means with respect to the detection frequency by the detection means and the estimation execution frequency by the estimation means. The first execution frequency is controlled to be higher than the second execution frequency in the third period subsequent to the second period.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which enables shortening of starting time can be provided, implement | achieving stable motor control.

It is a block diagram of a motor control device. It is a detailed block diagram of a motor speed estimation part. It is a figure which shows the change of the rotational speed of the motor at the time of transfering from forced commutation to SFOC. It is a figure which shows the process timing in SFOC in a steady state. It is a figure which shows the process timing immediately after switching to SFOC. It is a flowchart of a control mode switching process. It is a figure which shows the effect of a control mode switching process exemplarily. It is a figure which shows the processing timing of SFOC and engine control in a steady state. It is a figure which shows the processing timing of SFOC and engine control immediately after switching to SFOC. It is a flowchart of the control mode switching process in 2nd Embodiment.

  Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In addition, the following embodiment does not limit the invention which concerns on a claim. Although a plurality of features are described in the embodiment, all of the plurality of features are not necessarily essential to the invention, and the plurality of features may be arbitrarily combined. Furthermore, in the accompanying drawings, the same reference numerals are assigned to the same or similar components, and duplicate descriptions are omitted.

(First embodiment)
As a first embodiment of a motor control device according to the present invention, a motor control device that controls a three-phase brushless motor will be described below as an example.

<Device configuration>
FIG. 1 is a block diagram of the motor control device according to the first embodiment. The motor control device includes a controller and an engine unit.

  The engine unit includes a motor 100, a motor driver 106, and a motor current detection unit 101. Here, the motor 100 is a three-phase brushless motor. The motor driver 106 applies a pulse voltage to each coil end of the motor 100 to flow current. The motor current detection unit 101 detects a coil current flowing in each phase of the motor 100 (here, three phases (U, V, W)).

  The controller includes an overall control unit 110 and an SFOC (Sensorless Field Oriented Control) unit. The overall control unit 110 manages the engine unit and the SFOC unit in an integrated manner.

  The SFOC unit includes a motor speed estimation unit 102, a start control unit 103, a PI control unit 104, and a PWM control unit 105. The motor speed estimation unit 102 calculates the electrical angle and rotational speed of the motor from two input values of “three-phase current value” detected by the motor current detection unit 101 and “three-phase drive voltage value” applied to each coil end of the motor. Is estimated. The activation control unit 103 instructs the motor current detection unit 101 to detect motor current, and instructs the motor speed estimation unit 102 to perform estimation calculation. The PI control unit 104 performs proportional-integral calculation processing based on the motor rotation speed estimated by the motor speed estimation unit 102. The PWM control unit 105 controls the pulse voltage applied to each coil end of the motor 100 based on a command from the PI control unit 104.

  Here, it is assumed that the SFOC unit is realized by software by a processor (CPU) executing a program. However, part or all of the configuration may be realized by hardware such as an FPGA or a custom LSI.

  FIG. 2 is a detailed block diagram of the motor speed estimation unit 102. Motor speed estimation unit 102 includes a three-phase / two-phase conversion unit 120, an induced voltage calculation unit 130, a position calculation unit 140, and a speed calculation unit 150.

  The three-phase / two-phase conversion unit 120 uses the three-phase current values (iu, iv, iw) detected by the motor current detection unit 101 and the three-phase drive voltage values (Vu, Vv, Vw) output by the PWM control unit 105. Each is converted into a two-phase component and output. Those converted into the two-phase components are respectively referred to as a two-phase drive voltage (Va, Vb) and a two-phase current value (ia, ib).

The induced voltage calculator 130 calculates an A phase induced voltage (Ea) and a B phase induced voltage (Eb) from the two phase drive voltages (Va, Vb) and the two phase current values (ia, ib). This is specifically expressed as follows.
Ea = Va−R × ia−L × dia / dt
Eb = Vb−R × ib−L × dib / dt

  Here, R is a winding resistance, L is a winding inductance, and each has a unique value. Further, dia / dt and dib / dt indicate the rate of current change at a certain time.

The position calculation unit 140 calculates the position (θ) by obtaining an arc tangent with respect to the ratio of the A phase induced voltage (Ea) and the B phase induced voltage (Eb). This is specifically expressed as follows.
θ = tan ⁻¹ (−Eb / Ea)

The speed calculation unit 150 calculates the speed estimated value (ω) by obtaining the rate of change of the position (θ) at a certain time. This is specifically expressed as follows.
ω = dθ / dt

  FIG. 3 is a diagram exemplarily showing a change in the rotational speed of the motor when it is shifted from forced commutation to SFOC. Specifically, the rotational speed of the motor 100 in the prior art that simply switches from forced commutation mode control (forced commutation control) to SFOC is shown. The horizontal axis represents time (t), and the vertical axis represents motor rotation speed (rpm).

  At startup, first, the motor is driven in the forced commutation mode 203 from speed 0 (zero) to a predetermined threshold speed. In FIG. 3, the predetermined threshold speed is the control switching speed 202. When the motor reaches a predetermined speed, the control is switched from forced commutation control to SFOC. Thereafter, when the motor speed reaches the target speed 201, the acceleration command is interrupted. Thereafter, the motor is continuously driven at a constant speed until the target speed is changed.

  The control by the forced commutation mode referred to in the background art will be briefly described. The forced commutation mode is a method of applying a voltage to each phase of the motor by open loop control. Since the forced commutation mode consumes a large amount of current, it is not desirable to use it for a very long time. Therefore, it is preferable to switch from the forced commutation mode to the power-efficient SFOC as early as possible during startup. However, immediately after switching from the forced commutation mode to SFOC, the error in speed estimation is generally large. Therefore, it takes time until the motor speed converges to the target speed as shown by the curve of the starting characteristic 210.

  Therefore, in the first embodiment, it is considered that the error of speed estimation is reduced early by increasing the execution frequency of speed estimation (and current detection necessary for speed estimation) immediately after switching to SFOC.

  FIG. 4 is a diagram illustrating processing timing in SFOC in a steady state. The steady state is a state in which the motor 100 is stably operating at the target speed 201, for example. Here, the processing timing for two PWM control periods is shown.

  In FIG. 4, “PWM” indicates a cross flow conversion process for flowing a current to the motor. “ADC” indicates an analog-to-digital conversion process for detecting the motor current. “SFOC” indicates a motor control. For example, control related to coordinate transformation (three-phase two-phase transformation and rotational coordinate transformation) and speed estimation, speed control, current control, inverse coordinate transformation (stationary coordinate transformation and two-phase three-phase transformation) necessary for sensorless vector control Execute. “PWM data set” indicates PWM data output processing.

  First, current detection processing 301 by the motor current detection unit 101 is performed. Next, the motor speed estimation unit 102 performs a motor speed estimation process 302 that estimates the motor speed based on the detected current value. Thereafter, the PI control unit 104 performs a PI control process 303 based on the estimated speed, and performs a PWM data output process 304 that outputs data based on the PI control result to the PWM control unit 105.

  FIG. 5 is a diagram illustrating processing timing in SFOC immediately after switching to SFOC. As described above, the operation shown in FIG. 5 is specific to the first embodiment. In FIG. 4, each of the current detection process 301 and the motor speed estimation process 302 is executed once within one control cycle. On the other hand, in FIG. 5, each of the current detection process 301 and the motor speed estimation process 302 is executed twice within one control cycle.

  First, current detection processing 510 by the motor current detection unit 101 is performed at time t1. Next, the motor speed estimation unit 102 performs a motor speed estimation process 511 that estimates the motor speed (ω1) based on the detected current value.

  Thereafter, current detection processing 520 by the motor current detection unit 101 is performed at time t2. Next, the motor speed estimation unit 102 performs a motor speed estimation process 521 that estimates the motor speed (ω2) based on the detected current value. Thereafter, the PI control unit 104 performs a PI control process 303 based on the estimated speed (ω2), and performs a PWM data output process 304 that outputs data based on the PI control result to the PWM control unit 105.

  In the above description, an example in which the frequency of current detection and speed estimation calculation is doubled is shown. However, the current detection is performed in a range that can be completed up to the PWM data output process 304 before the next control cycle starts. And the execution frequency of speed estimation can be further increased.

  FIG. 6 is a flowchart of the control mode switching process in the first embodiment. In S601, the overall control unit 110 starts motor control in the forced commutation mode. Also, acquisition of the rotation speed of the motor 100 is started. The rotation speed of the motor 100 may be acquired by operating the motor speed estimation unit 102 of the SFOC unit, or may be acquired using a separate encoder. In S602, the overall control unit 110 determines whether or not the rotation speed of the motor 100 has reached the switching speed to SFOC (control switching speed 202), and when it reaches the switching speed, proceeds to S603.

  In S603, the overall control unit 110 switches to motor control by SFOC. In S604, the overall control unit 110 increases the frequency of current detection and speed estimation. For example, control is performed so that current detection and speed estimation are performed twice per control cycle.

  In S605, the overall control unit 110 determines whether or not the rotational speed of the motor 100 has reached the target speed 201. When the overall speed reaches the target speed 201, the overall control unit 110 proceeds to S606. In S606, the overall control unit 110 decreases the cycle of current detection and speed estimation. For example, control is performed so as to perform current detection and speed estimation once per control cycle.

  FIG. 7 is a diagram exemplarily showing the effect of the control mode switching process. Specifically, FIG. 3 shows the rotation speed of the motor 100 when the control shown in FIG. 5 is performed after the start of control by SFOC (after reaching the control switching speed 202). Similar to FIG. 3, the horizontal axis represents time (t) and the vertical axis represents motor speed (rpm).

  At startup, first, the motor 100 is driven in the forced commutation mode 203 from a speed of 0 (zero) to a predetermined speed. When the motor reaches a control switching speed 202 that is a predetermined threshold speed, the control is switched from the forced commutation mode to SFOC. Immediately after the control is switched to SFOC, the frequency of current detection and speed estimation is increased as shown in FIG. Thereby, the difference from the target speed is corrected at a time interval shorter than the control cycle. As a result, as shown by the curve of the start characteristic 710, the speed followability improves with respect to the target speed 201. Thereafter, when the motor speed reaches the target speed 201, the acceleration command is interrupted. Further, as shown in FIG. 4, the frequency of current detection and speed estimation is lowered. Thereafter, the motor is continuously driven at a constant speed until the target speed is changed.

  As described above, according to the first embodiment, in motor control, motor drive in the forced commutation mode is performed at the time of startup, and the motor drive is switched to SFOC. Immediately after switching to SFOC, the frequency of executing current detection and speed estimation is increased. As a result, it is possible to suppress the estimation error of the motor speed immediately after switching to SFOC, and to shorten the start-up time while realizing stable motor control.

(Modification)
In the first embodiment described above, the control is switched to the SFOC control with the trigger that the rotational speed of the motor has reached the predetermined threshold speed. However, the control may be switched to the SFOC control based on another trigger. For example, it may be configured to switch to SFOC after a first period (for example, a predetermined number of control cycles) has elapsed since the start of motor control.

  In the first embodiment described above, the frequency of executing the current detection and speed estimation is lowered by using the trigger that the motor rotational speed has reached the target speed. However, the current detection and speed are determined based on other triggers. The estimation execution frequency may be lowered. For example, the frequency of current detection and speed estimation may be reduced in a third period following the elapse of a second period (for example, a predetermined number of control cycles) after shifting to SFOC. It is sufficient to increase the frequency of current detection and speed estimation in at least one control cycle immediately after switching to SFOC.

  Moreover, although the example which performs the current detection and speed estimation immediately after switching to SFOC twice in one control cycle was demonstrated, it is good also as N times (N is an integer greater than or equal to 2). In that case, you may comprise so that the frequency | count in 1 control period may be reduced gradually. For example, it may be configured such that it is executed three times immediately after shifting to the control by SFOC, reduced to two executions after a predetermined time has elapsed, and reduced to one execution after reaching the target speed.

(Second Embodiment)
In the first embodiment, the current detection and speed estimation execution frequency is increased immediately after switching to SFOC, and after the target speed is reached, the current detection and speed estimation execution frequency is set back to the original setting. In the second embodiment, an example will be described in which the control of the frequency of execution of current detection and speed estimation immediately after switching to SFOC is performed according to the status of other engine control processes.

  Examples of other engine control processing here include processing for controlling various processes such as charging, exposure, development, transfer, and fixing in a laser beam printer. These engine control processes are performed asynchronously with the control cycle of SFOC, and may be completed within a predetermined time from a certain trigger (for example, an interrupt notification indicating that the transported paper has reached a predetermined position). It is the control of properties.

  Note that when the engine control process and the SFOC process are performed by one CPU, the time division process is performed by switching the time interval. The engine control process is managed and implemented by the overall control unit 110 as in the case of SFOC.

  FIG. 8 is a diagram showing the processing timing of SFOC and engine control in a steady state. The steady state is a state in which the motor 100 is stably operating at the target speed 201, for example. Here, similarly to FIG. 4, the processing timing for two PWM control cycles is shown.

  The current detection process 301, the motor speed estimation process 302, the PI control process 303, and the PWM data output process 304 are the same as those in FIG. As described above, “engine control processing” indicates processing for controlling various processes in the laser beam printer, and the engine control processing 801 is performed within the control cycle 300.

  The processing time and execution of the “engine control process” are managed by the overall control unit 110 and executed in parallel with the PWM data output process 304. The “engine control process” is managed and implemented by the overall control unit 110, but the “PWM data output process” is managed and implemented by the PWM module (hardware), so that the process can proceed in parallel. ing.

  FIG. 9 is a diagram showing the processing timing of SFOC and engine control immediately after switching to SFOC. In FIG. 8, each of the current detection process and the motor speed estimation process is executed once within one control cycle. On the other hand, in FIG. 9, each of the current detection process and the motor speed estimation process is executed twice within one control cycle.

  First, at time t1, it is determined whether the frequency of current detection and speed estimation calculation within the control cycle 300 can be increased. As a determination criterion, for example, first, it is determined whether or not there is engine control to be performed within the control cycle 300. In some cases, the processing time of the engine control process to be controlled is predicted and divided, and whether or not the divided engine control process 902 can be executed even if the frequency of the current detection process and the motor speed estimation process is increased within one control cycle. to decide. If there is no engine control to be controlled within the control cycle 300, the PWM data output processing 304 is performed even if the current detection processing and the motor speed estimation processing are increased within one control cycle as in the first embodiment. Judge whether it is possible.

If there is an engine control to be performed within the control cycle 300 and the determination of whether the frequency of the current detection process and the motor speed estimation process can be increased is expressed by an expression, for example, the following is obtained.
(T2-t1)> Ta (1)
(T3-t2)> Tb (2)

here,
Ta: Total expected processing time of current detection 510, speed estimation 511, and divided engine control processing 901 (because it is predicted from the previous control cycle or history of a certain period, it is estimated to be less Absent)
Tb: Total expected processing time of the current detection 520, speed estimation 521, PI control 303, divided engine control processing 902, and PWM data output processing 304, whichever is longer, (Since it is predicted from the control cycle and the history of a certain period, it will not be underestimated)
It is.

  It is a condition that the frequency of current detection and speed estimation calculation can be increased that Expression (1) and Expression (2) hold simultaneously. In addition, when either one of the expressions (1) and (2) does not hold, the division ratio between the engine control process 901 and the engine control process 902 is adjusted so that the expressions (1) and (2) hold. May be. (FIG. 9 shows an example in which it is determined that the frequency of current detection processing and motor speed estimation processing can be increased, and current detection and speed estimation calculation are performed twice in one control cycle.)

  The processes after the above determination will be described in order. The motor current detection unit 101 performs current detection processing 510. Next, the motor speed estimation unit 102 performs a motor speed estimation process 511 that estimates the motor speed (ω1) based on the detected current value. When the motor speed estimation process 511 ends, a divided engine control process 901 is performed.

  Thereafter, at time t2, the motor current detection unit 101 performs a current detection process 520. Next, the motor speed estimation unit 102 performs a motor speed estimation process 521 that estimates the motor speed (ω2) based on the detected current value. Thereafter, the PI control unit 104 performs a PI control process 303 based on the estimated speed (ω2), and performs a PWM data output process 304 that outputs data based on the PI control result to the PWM control unit 105. In parallel with the PWM data output process 304, the other divided engine control process 902 is executed. (As described above, the engine control process and the PWM data output process can be performed in parallel.)

  In the above description, an example in which the frequency of current detection and speed estimation calculation is doubled is shown, but a frequency other than double may be used. Prior to the start of the next control cycle, it is possible to further increase the frequency of execution of current detection and speed estimation within a range in which one of the divided engine control processing and PWM data output processing 304 can be completed up to the longer processing time.

  FIG. 10 is a flowchart of the control mode switching process in the second embodiment. Steps S601 to S603 are the same as those in FIG.

  In S1000, the overall control unit 110 determines whether or not there is an engine control process to be controlled within the control cycle 300 at t1 in FIG. If yes, go to S1001, otherwise go to S604.

  In S1001, the overall control unit 110 predicts the processing time of the engine control process to be controlled within the control cycle 300 at t1 in FIG. As a method for predicting the processing time, the processing time may be predicted based on the processing performed in the previous control cycle, or the processing time based on the processing performed in the control cycle of a certain period. The method of predicting may be used. Since it is predicted from the previous control cycle or a history of a certain period, it is not estimated too little.

  In S1002, the overall control unit 110 divides the predicted engine control process. The engine control processing division method may be equal division, or may be unequal division according to the priority of the processing in the control cycle 300. Moreover, it is not necessary to divide.

  In addition, immediately after switching to SFOC, a method may be used in which the priority of the engine control process is lowered and the processing time required for the engine control process is intentionally shortened. Further, as described above, if either of the expressions (1) and (2) does not hold, the engine control process 901 and the engine control process 902 are set so that the expressions (1) and (2) hold. The division ratio may be adjusted.

  In S1003, the overall control unit 110 determines whether or not the cycle of current detection and speed estimation calculation can be increased. Specifically, the above conditions (1) and (2) are satisfied at the same time, which is a condition for increasing the period of current detection and speed estimation calculation. If the condition is satisfied, the process proceeds to S604, and if the condition is not satisfied, the process proceeds to S605. Henceforth, since S604-S606 is the same as that of FIG. 6, description is abbreviate | omitted. If it is determined at time t1 that the frequency of current detection and speed estimation calculation cannot be increased, the processing timing shown in FIG. 8 is reached.

  As described above, according to the second embodiment, in motor control, motor driving in the forced commutation mode is performed at the time of startup, and the motor driving is switched to SFOC. In particular, the execution frequency of current detection and speed estimation immediately after switching to SFOC is determined according to the load status of other engine control processing (that is, processing other than vector control). Thereby, even when SFOC processing and other engine control processing are performed by one CPU, it is possible to efficiently change the execution frequency of current detection and speed estimation.

  As a result, it is possible to suppress the estimation error of the motor speed immediately after switching to SFOC, and to shorten the start-up time while realizing stable motor control.

(Other examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

  The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the claims are appended to publicize the scope of the invention.

  DESCRIPTION OF SYMBOLS 100 Motor; 101 Motor current detection part; 102 Motor speed estimation part; 103 Start-up control part; 104 PI control part; 105 PWM control part; 106 Motor driver;

Claims (10)

A motor control device for controlling a motor,
Detecting means for detecting a current flowing through the motor;
Estimating means for estimating the rotational speed of the motor from the current detected by the detecting means;
First driving means for driving the motor by forced commutation control;
Second driving means for driving the motor by vector control based on the rotational speed of the motor estimated by the estimating means;
Control is performed so that the motor is driven by the first driving means until the first period from the start of control of the motor, and the second driving means is provided after the first period has elapsed. First control means for controlling the motor to be driven by:
Second control means for controlling the execution frequency of the detection means and the estimation means;
Have
The second control means has a second period after switching from driving by the first driving means to driving by the second driving means with respect to the detection frequency by the detection means and the estimation execution frequency by the estimation means. The motor control device is configured to control the first execution frequency so that the first execution frequency is higher than the second execution frequency in a third period subsequent to the second period. 2. The motor control device according to claim 1, wherein the first period is a period from a start of control of the motor until a rotation speed of the motor reaches a predetermined threshold speed. 3. The motor control according to claim 1, wherein the second period is a period from when switching to driving by the second driving unit to when the rotation speed of the motor reaches a target speed. apparatus. 4. The motor control device according to claim 1, wherein the third period is a period during which the motor rotates at a target speed. 5. The said 2nd drive means performs the said vector control according to the difference of the rotational speed of the said motor estimated by the said estimation means, and target speed, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Motor control device. The first execution frequency is a frequency of N times (N is an integer of 2 or more) in one control cycle in the second driving unit,
6. The motor control device according to claim 1, wherein the second execution frequency is a frequency of once in one control cycle of the second drive unit. The second control means determines whether or not to increase the first execution frequency based on a load state of processing other than the vector control in the second period. The motor control device according to any one of 1 to 6. The second control means increases the first execution frequency by raising the priority of the vector control over the processing other than the vector control in the second period. The motor control device according to any one of 1 to 7. A control method of a motor control device for controlling a motor,
The motor control device
Detecting means for detecting a current flowing through the motor;
Estimating means for estimating the rotational speed of the motor from the current detected by the detecting means;
First driving means for driving the motor by forced commutation control;
Second driving means for driving the motor by vector control based on the rotational speed of the motor estimated by the estimating means;
Have
The control method is:
Control is performed so that the motor is driven by the first driving means until the first period from the start of control of the motor, and the second driving means is provided after the first period has elapsed. A first control step for controlling to drive the motor by:
Regarding the execution frequency of detection by the detection means and estimation by the estimation means, the first execution frequency in the second period after switching from driving by the first driving means to driving by the second driving means is: A second control step of controlling to be higher than a second execution frequency in a third period following the second period;
A control method for a motor control device.   The program for functioning a computer as each means of the motor control apparatus of any one of Claims 1 thru | or 8.

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