Motor drive control device, motor unit, and motor drive control method

Abstract

To improve both stability of rotation speed and responsiveness of a motor in speed control of the motor.SOLUTION: A motor drive control device 2 comprises: a drive circuit 6 for applying a voltage onto a coil of a motor 3 on the basis of a drive control signal Sd for controlling drive of the motor 3, to drive the motor 3; and a control circuit 5 for performing feedback control that generates the drive control signal Sd so that a rotation speed Sr of the motor 3 matches a target rotation speed Stg. The control circuit 5 stepwisely changes a gain Sg so as to reduce the gain Sg of the feedback control as a deviation Sdf of the rotation speed Sr of the motor 3 from the target rotation speed Stg decreases.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor drive control device, a motor unit, and a motor drive control method. [Background technology]

[0002] A known method for controlling motors such as fan motors is speed control, which controls the rotational speed of the motor so that it coincides with a target rotational speed. In motor speed control, it is desirable for the rotational speed of the motor to reach the target rotational speed in as short a time as possible.

[0003] A known method for improving the responsiveness of the motor rotation speed is to increase the motor control amount in response to the error between the target rotation speed and the motor rotation speed, that is, to increase the gain of the speed control.

[0004] Increasing the gain of motor speed control can improve the responsiveness of the motor's rotational speed, for example, when the motor is started or when the target rotational speed is changed. However, this increases the likelihood of the motor's rotational speed overshooting or undershooting the target rotational speed, reducing the stability of the rotational speed. Overshooting or undershooting can cause the motor to produce abnormal noise (e.g., undulating noise), which is undesirable.

[0005] As a technique for improving the stability of the rotation speed in the speed control of a motor, for example, a technique for continuously changing the gain of the speed control in accordance with the error of the rotation speed from a target value is known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. Hei 1-198290 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the motor control device disclosed in Patent Document 1 continuously reduces the gain of motor speed control as shown in Figure 3 of the document, and so although it can improve the stability of the motor's rotational speed, it cannot be expected to improve the responsiveness of the rotational speed. In other words, although it can suppress the occurrence of overshoot and undershoot, it tends to take a long time for the motor's rotational speed to reach the target rotational speed.

[0008] The present invention has been made to solve the above-mentioned problems, and has as its object to improve both the stability and responsiveness of the rotation speed of a motor in motor speed control. [Means for solving the problem]

[0009] A motor drive control device according to a representative embodiment of the present invention comprises a drive circuit that applies a voltage to a coil of the motor to drive the motor based on a drive control signal for controlling the drive of the motor, and a control circuit that performs feedback control to generate the drive control signal so that the rotational speed of the motor matches a target rotational speed, and is characterized in that the control circuit changes the gain of the feedback control in a stepped manner so that the gain becomes smaller as the deviation of the rotational speed of the motor from the target rotational speed becomes smaller. [Effects of the Invention]

[0010] According to one aspect of the present invention, in motor speed control, it is possible to improve both the stability and responsiveness of the rotation speed of the motor. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing the configuration of a motor unit equipped with a motor drive control device according to a first embodiment of the present invention. [Figure 2] 5 is a diagram for explaining the correspondence relationship between the rotation speed of the motor and the designated value of the gain according to the first embodiment. FIG. [Figure 3] FIG. 4 is a diagram showing an example of a gain table according to the first embodiment. [Figure 4] 4 is a flowchart showing the flow of a gain adjustment process performed by the motor drive control device according to the first embodiment. [Figure 5] 10 is a flowchart showing the flow of a transient response determination process (step S5). [Figure 6] FIG. 10 is a diagram showing the changes over time in gain and rotation speed of the motor drive control device according to the first embodiment when the motor is accelerating, and the changes over time in gain and rotation speed of feedback control of the prior art in which the gain is kept constant, as a comparative example. [Figure 7] FIG. 10 is a diagram showing the temporal changes in gain and rotation speed of the motor drive control device according to the first embodiment when the motor is decelerating, and the temporal changes in gain and rotation speed of feedback control of the prior art in which the gain is kept constant, as a comparative example. [Figure 8] FIG. 10 is a diagram showing the changes over time in gain and rotation speed of the motor drive control device according to the first embodiment when the motor accelerates, and the changes over time in gain and rotation speed of a conventional technique, as a comparative example, in which the gain is continuously changed according to the deviation in rotation speed. [Figure 9] FIG. 10 is a diagram showing temporal changes in gain and rotation speed of the motor drive control device according to the first embodiment when the motor is decelerating, and also showing temporal changes in gain and rotation speed of a conventional technique, as a comparative example, in which the gain is continuously changed according to the deviation in rotation speed. [Figure 10] 5 is a diagram showing temporal changes in gain and rotation speed of the motor drive control device according to the first embodiment when the motor is accelerating. FIG. [Figure 11] 5 is a diagram showing temporal changes in gain and rotation speed of the motor drive control device according to the first embodiment when the motor is decelerating. FIG. [Figure 12] 5 is a diagram showing temporal changes in the gain and rotation speed of the motor drive control device according to the first embodiment when the rotation speed of the motor changes after reaching a target rotation speed. FIG. [Figure 13] FIG. 10 is a diagram showing the configuration of a motor unit equipped with a motor drive control device according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a diagram for explaining the correspondence relationship between the rotation speed of the motor and the designated value of the gain according to the second embodiment. [Figure 15] FIG. 10 is a diagram showing an example of a gain table when the motor is accelerating according to the second embodiment. [Figure 16] FIG. 10 is a diagram showing an example of a gain table when the motor is decelerating according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1. Overview of the embodiment First, a typical embodiment of the invention disclosed in this application will be outlined. In the following description, for example, reference numerals in the drawings corresponding to components of the invention are written in parentheses.

[0013] [1] A motor drive control device (2, 2A) according to a representative embodiment of the present invention includes a drive circuit (6) that applies a voltage to a coil of a motor (3) to drive the motor based on a drive control signal (Sd) for controlling the drive of the motor, and a control circuit (5, 5A) that performs feedback control to generate the drive control signal so that the rotational speed (Sr) of the motor coincides with a target rotational speed (Stg), and the control circuit is characterized in that it changes the gain (Sg) of the feedback control in a stepwise manner so that the smaller the deviation (Sdf) of the rotational speed of the motor from the target rotational speed, the smaller the gain of the feedback control.

[0014] [2] In the motor drive control device described in [1] above, a specified value of the gain may be set for each of a plurality of divisions (Rd1 to Rd3, Ra1 to Ra3) representing the magnitude of the deviation, and the control circuit may calculate the deviation, select the specified value set for the division to which the calculated deviation belongs, and perform the feedback control based on the selected specified value.

[0015] [3] In the motor drive control device described in [2] above, when the control circuit determines that a transient response has occurred that includes at least one of an overshoot and an undershoot of the rotational speed of the motor relative to the target rotational speed, the control circuit may change the gain to a value (G0) that is smaller than the specified value selected immediately before, and perform the feedback control.

[0016] [4] In the motor drive control device described in [3] above, the control circuit may determine whether or not the transient response has occurred when the target rotation speed is equal to or greater than a predetermined threshold value (Sth).

[0017] [5] In the motor drive control device described in [3] or [4] above, when the control circuit changes the gain to a value (G0) smaller than the specified value, the control circuit may fix the gain regardless of the calculated deviation.

[0018] [6] In the motor drive control device (2A) described in any one of [2] to [5] above, the rate of change of the specified value with respect to the deviation in a range (Ra1 to Ra3) in which the rotation speed is smaller than the target rotation speed and the rate of change of the specified value with respect to the deviation in a range (Rd1 to Rd3) in which the rotation speed is larger than the target rotation speed may be different from each other.

[0019] [7] In the motor drive control device (2A) described in [6] above, the width of the section (Ra1 to Ra3) in the range where the rotation speed is smaller than the target rotation speed and the width of the section (Rd1 to Rd3) in the range where the rotation speed is larger than the target rotation speed may be different from each other.

[0020] [8] In the motor drive control device described in [6] or [7] above, the designated values ​​(Ga0 to Ga3) associated with the range (Ra1 to Ra3) in which the rotation speed is smaller than the target rotation speed and the designated values ​​(Gd0 to Gd3) associated with the range (Rd1 to Rd3) in which the rotation speed is larger than the target rotation speed may be different from each other.

[0021] [9] A motor unit (1, 1A) according to a representative embodiment of the present invention is characterized by comprising the motor drive control device (2, 2A) described in any one of [1] to [8] above, and the motor (3).

[0022]

[10] A motor drive control method according to a representative embodiment of the present invention is a motor drive control method for performing feedback control so that the rotational speed (Sr) of a motor (3) coincides with a target rotational speed (Stg), and is characterized by including a first step (S1) of detecting the rotational speed of the motor, and a second step (S5 to S11) of changing the gain of the feedback control in a stepwise manner so that the gain decreases as the deviation of the rotational speed detected in the first step from the target rotational speed decreases.

[0023] 2. Specific examples of embodiments Hereinafter, specific examples of embodiments of the present invention will be described with reference to the drawings. In the following description, components common to the embodiments will be designated by the same reference numerals, and repeated description will be omitted.

[0024] First Embodiment FIG. 1 is a diagram showing the configuration of a motor unit 1 equipped with a motor drive control device 2 according to a first embodiment of the present invention.

[0025] The motor unit 1 shown in FIG. 1 includes a motor 3, a position detector 4, and a motor drive control device 2.

[0026] The motor 3 is a motor having at least one coil. For example, the motor 3 is a brushless DC motor having three-phase (U-phase, V-phase, and W-phase) coils (windings). The motor 3 functions as a fan motor, for example, by connecting an impeller (not shown) to the output shaft of the motor 3.

[0027] The position detector 4 is a device that generates a position detection signal Sh that corresponds to the rotation of the rotor of the motor 3. The position detector 4 is, for example, a Hall element. The Hall element detects the magnetic poles of the rotor and outputs a Hall signal whose voltage changes according to the rotation of the rotor. The Hall signal output from the position detector 4 is, for example, a pulse signal, and is input to the motor drive control device 2 as the position detection signal Sh.

[0028] The motor drive control device 2 is a device that controls the driving of the motor 3. The motor drive control device 2 controls the driving of the motor 3, for example, so that the rotation speed Sr of the motor 3 matches the target rotation speed Stg.

[0029] Specifically, the motor drive control device 2 includes a control circuit 5 and a drive circuit 6. The motor drive control device 2 receives a DC voltage from an external DC power supply (not shown). The DC voltage is supplied to a power supply line (not shown) within the motor drive control device 2 via, for example, a protection circuit, and is input as a power supply voltage to the control circuit 5 and the drive circuit 6 via the power supply line.

[0030] The drive circuit 6 is a circuit that drives the motor 3 based on a drive control signal Sd output from the control circuit 5. The drive control signal Sd is a signal for controlling the driving of the motor 3, and is, for example, a PWM (Pulse Width Modulation) signal.

[0031] The drive circuit 6 is, for example, an inverter circuit having a plurality of transistors as switching elements. The drive circuit 6 switches the connection destination of the coil of the motor 3 between a DC voltage and a ground potential in response to, for example, a PWM signal as the drive control signal Sd, thereby switching the direction of the motor current and rotating the motor 3.

[0032] The drive circuit 6 may include a pre-drive circuit for driving each transistor constituting the inverter circuit based on the drive control signal Sd. A sense resistor for detecting the motor current may be connected to the inverter circuit.

[0033] The control circuit 5 is a circuit for comprehensively controlling the operation of the motor drive control device 2. In this embodiment, the control circuit 5 is a program processing device having a configuration in which a processor such as a CPU, various storage devices such as RAM, ROM, and flash memory, and peripheral circuits such as a counter (timer), an A / D conversion circuit, a D / A conversion circuit, a clock generation circuit, and an input / output interface circuit are interconnected via a bus or dedicated lines. For example, the control circuit 5 is a microcontroller (MCU: Micro Controller Unit).

[0034] The control circuit 5 and the drive circuit 6 may be configured to be packaged as a single semiconductor integrated circuit (IC: Integrated Circuit), or may be configured to be packaged as separate integrated circuits, mounted on a circuit board, and electrically connected to each other on the circuit board.

[0035] The control circuit 5 has a speed feedback function that performs feedback control to generate a drive control signal Sd so that the rotation speed Sr of the motor 3 coincides with the target rotation speed Stg. In addition to the speed feedback function, the control circuit 5 also has a gain adjustment function that, when performing feedback control of the rotation speed Sr of the motor 3, changes the gain of the feedback control in accordance with the deviation (speed deviation) Sdf of the rotation speed Sr of the motor 3 from the target rotation speed Stg.

[0036] The control circuit 5 has, as functional units for realizing the above-mentioned functions, for example, as shown in FIG. 1, a drive command analysis unit 10, a rotational speed calculation unit 11, a speed deviation calculation unit 12, a gain determination unit 13, an operation amount calculation unit 14, a drive control signal generation unit 15, and a transient response determination unit 16.

[0037] Each of the above-described functional units of the control circuit 5 is realized, for example, by program processing of an MCU serving as the control circuit 5. Specifically, a processor constituting the MCU serving as the control circuit 5 performs various calculations in accordance with programs stored in a memory, and controls each of the peripheral circuits constituting the MCU, thereby realizing each of the above-described functional units.

[0038] First, the functional section for realizing the velocity feedback function will be mainly described. The drive command analysis unit 10 receives, for example, a drive command signal Sc output from a higher-level device (not shown) provided outside the motor drive control device 2. The drive command signal Sc is a signal indicating a target value for driving the motor 3, such as a speed command signal indicating a target rotation speed Stg of the motor 3.

[0039] The drive command analyzer 10 analyzes the drive command signal Sc to obtain information on the specified target rotation speed Stg. For example, if the drive command signal Sc is a PWM signal having a duty ratio corresponding to the target rotation speed Stg, the drive command analyzer 10 analyzes the duty ratio of the drive command signal Sc and outputs information on the rotation speed corresponding to the duty ratio as the target rotation speed Stg.

[0040] The rotation speed calculation unit 11 is a functional unit that calculates the actual rotation speed Sr of the motor 3. The rotation speed calculation unit 11 calculates and outputs the rotation speed Sr of the motor 3 based on the position detection signal (e.g., a Hall signal) Sh output from the position detector 4.

[0041] The speed deviation calculation unit 12 is a functional unit that calculates a deviation (speed deviation) Sdf of the rotation speed Sr of the motor 3 from the target rotation speed Stg. The speed deviation calculation unit 12 calculates the deviation Sdf (=Stg-Sr) by, for example, subtracting the rotation speed Sr calculated by the rotation speed calculation unit 11 from the target rotation speed Stg output from the drive command analysis unit 10.

[0042] The operation amount calculation unit 14 is a functional unit that calculates the operation amount So for driving the motor 3.

[0043] The manipulated variable So is information that specifies the drive amount of the motor 3 required to make the rotation speed Sr of the motor 3 coincide with the target rotation speed Stg (to make the deviation Sdf zero).

[0044] The operation amount calculation unit 14 calculates the operation amount So by performing a PID (Proportional-Integral-Differential) control calculation using, for example, the value of the feedback control gain Sg determined by the later-described gain determination unit 13. For example, the operation amount calculation unit 14 calculates the operation amount So such that the rotational speed control amount of the motor 3 increases as the gain Sg increases.

[0045] The drive control signal generator 15 is a functional unit that generates a drive control signal Sd based on the operation amount So calculated by the operation amount calculator 14. For example, the drive control signal generator 15 generates a PWM signal having a duty ratio according to the operation amount So and outputs it as the drive control signal Sd. The drive circuit 6 drives the motor 3 based on the drive control signal Sd output from the drive control signal generator 15.

[0046] Next, a functional section for mainly realizing the gain adjustment function will be described. As a gain adjustment function, the control circuit 5 changes the gain Sg of the feedback control in a stepwise manner so that the smaller the deviation Sdf of the rotation speed Sr of the motor 3 from the target rotation speed Stg, the smaller the gain Sg of the feedback control becomes.

[0047] Specifically, the control circuit 5 has a gain determination unit 13 and a transient response determination unit 16 as functional units for gain adjustment. Although details will be described later, the gain determination unit 13 has a gain table 20 in which a designated value of the gain Sg is set for each of a plurality of sections (ranges) that represent the magnitude of the deviation Sdf. The gain determination unit 13 refers to the gain table 20, selects the designated value of the gain Sg that is set for the section to which the deviation Sdf input from the speed deviation calculation unit 12 belongs, and performs feedback control based on the selected designated value.

[0048] Furthermore, as will be described in detail later, the transient response determination unit 16 determines whether or not a transient response has occurred in the rotation speed Sr based on the input deviation Sdf, and if it determines that a transient response has occurred, it generates a transient response notification signal Str notifying the occurrence of the transient response and outputs it to the gain determination unit 13.

[0049] FIG. 2 is a diagram illustrating the correspondence relationship between the rotation speed Sr of the motor 3 and the designated value of the gain Sg according to the first embodiment.

[0050] As shown in Fig. 2, in the motor drive control device 2 according to the first embodiment, the specified value of the gain Sg for the rotation speed Sr of the motor 3 is set in stages according to the magnitude of the deviation Sdf of the rotation speed Sr from the target rotation speed Stg. For example, Fig. 2 shows a case in which the magnitude of the deviation Sdf is divided into three ranges (divisions) on both the positive and negative sides of the target rotation speed Stg based on the values ​​α, β, and γ of the deviation Sdf, and a specified value of the gain Sg is set for each range.

[0051] For example, in FIG. 2, when the value of the deviation Sdf with respect to the target rotation speed Stg is within the range of ±α, that is, for the divisions Rd1 and Ra1 of the deviation Sdf, "G1" is set as the specified value of the gain Sg. Further, when the value of the deviation Sdf with respect to the target rotation speed Stg is within the range from ±α to ±β, that is, for the divisions Rd2 and Ra2 of the deviation Sdf, "G2" is set as the specified value of the gain Sg. Further, when the value of the deviation Sdf with respect to the target rotation speed Stg is in the range exceeding ±β, that is, for the divisions Rd3 and Ra3 of the deviation Sdf, "G3" is set as the specified value of the gain Sg. Here, the magnitude relationship of the specified values of the gain Sg is G1 < G2 < G3. Thus, in the motor drive control device 2 according to the first embodiment, the gain Sg is set to be smaller as the deviation Sdf is smaller.

[0052] Specifically, the gain determination unit 13 of the control circuit 5 determines the magnitude of the gain Sg for feedback control based on the correspondence between the range (division) representing the magnitude of the deviation Sdf and the specified value of the gain Sg as shown in FIG. 2. For example, the gain determination unit 13 has a gain table 20 which is information showing the correspondence between the range (division) representing the magnitude of the deviation Sdf and the specified value of the gain Sg, and determines the magnitude of the gain Sg for feedback control by referring to the gain table 20 based on the calculated value of the deviation Sdf.

[0053] FIG. 3 is a diagram showing an example of the gain table 20 according to the first embodiment. As shown in FIG. 3, the gain table 20 is a table associating the range (division) representing the magnitude of the deviation Sdf with the specified value of the gain Sg.

[0054] When determining the magnitude of the gain Sg, the gain determination unit 13 reads out the specified value of the gain Sg corresponding to the value of the deviation Sdf calculated by the speed deviation calculation unit 12 from the gain table 20, and determines the read specified value as the magnitude of the gain Sg. For example, when the absolute value |Sdf| of the deviation Sdf is greater than the value α of the deviation Sdf and less than or equal to the value β of the deviation Sdf, the gain determination unit 13 sets the specified value of the gain Sg to "G2".

[0055] In this way, by dividing the magnitude of the deviation Sdf into multiple sections with a predetermined width and setting the specified value of the gain Sg to be larger the further the section is from the target rotation speed Stg, it is possible to control the feedback control gain Sg to decrease in a stepped manner as the rotation speed Sr approaches the target rotation speed Stg.

[0056] In addition, as a gain adjustment function, the control circuit 5 may change the gain Sg to a value smaller than the specified value selected immediately before when it determines that a transient response has occurred that includes at least one of an overshoot and an undershoot of the rotation speed Sr of the motor 3 relative to the target rotation speed Stg.

[0057] Specifically, the transient response determination unit 16 of the control circuit 5 determines whether or not there is a transient response in the rotation speed Sr, and the gain determination unit 13 of the control circuit 5 changes the gain Sg based on the determination result by the transient response determination unit 16.

[0058] The transient response determination unit 16 performs a transient response determination process to determine whether or not a transient response has occurred based on the deviation Sdf calculated by the speed deviation calculation unit 12.

[0059] The transient response determination unit 16 may use the magnitude of the deviation Sdf in addition to whether the polarity (positive / negative) of the deviation Sdf has switched as a criterion for determining whether a transient response has occurred. For example, when the transient response determination unit 16 detects that the polarity of the deviation Sdf (=Stg-Sr) has switched from positive (+) to negative (-) and that the deviation Sdf is +γ or greater (the rotation speed Sr is equal to or greater than "Stg+γ"), it determines that an overshoot of the rotation speed Sr with respect to the target rotation speed Stg has occurred. Furthermore, when the transient response determination unit 16 detects that the polarity of the deviation Sdf (=Stg-Sr) has switched from negative (-) to positive (+) and that the deviation Sdf is -γ or greater (the rotation speed Sr is equal to or less than "Stg-γ"), it determines that an undershoot of the rotation speed Sr with respect to the target rotation speed Stg has occurred.

[0060] Further, the above-described transient response determination process may be executed only in a situation where overshoot or undershoot of the rotational speed Sr is likely to occur.

[0061] For example, overshoot or undershoot of the rotational speed Sr is likely to occur when the rotational speed Sr is changing toward the target rotational speed Stg at the start of driving of the motor 3 or after the change of the target rotational speed Stg, that is, when the motor 3 is accelerating or decelerating.

[0062] Therefore, when the motor 3 is accelerating or decelerating, in other words, when the rotational speed Sr is not stable, the transient response determination unit 16 may execute the transient response determination process. For example, when the rotational speed Sr of the motor 3 is within the range of the value ±γ of the deviation Sdf centered on the target rotational speed Stg (Stg - γ < Sr < Stg + γ), the transient response determination unit 16 does not perform the transient response determination process. On the other hand, when the rotational speed Sr of the motor 3 is not within the range of the value ±γ of the deviation Sdf centered on the target rotational speed Stg (Sr ≦ Stg - γ, Stg + γ ≦ Sr), the transient response determination unit 16 performs the transient response determination process.

[0063] Also, overshoot or undershoot of the rotational speed Sr tends to occur as the target rotational speed Stg is higher. Therefore, when the target rotational speed Stg is set to a predetermined threshold value Sth or more, the transient response determination unit 16 may perform the transient response determination process. As described above, when the transient response determination unit 16 determines that a transient response has occurred, it generates a transient response notification signal Str notifying the occurrence of the transient response and outputs it to the gain determination unit 13.

[0064] When the gain determination unit 13 receives a transient response notification signal Str output from the transient response determination unit 16, it changes the gain Sg to a value smaller than the specified value selected immediately before. For example, when the specified value of the gain Sg is set to "G1" and the motor 3 is accelerating, if the rotation speed Sr becomes equal to or greater than (Stg+γ), the transient response determination unit 16 determines that an overshoot of the rotation speed Sr has occurred. In this case, the gain determination unit 13 sets the specified value of the gain Sg to "G0", which is smaller than "G1". Similarly, when the specified value of the gain Sg is set to "G1" and the motor 3 is decelerating, if the rotation speed Sr becomes equal to or less than (Stg-γ), the transient response determination unit 16 determines that an undershoot of the rotation speed Sr has occurred. In this case, the gain determination unit 13 sets the specified value of the gain Sg to "G0", which is smaller than "G1".

[0065] In this way, when the occurrence of a transient response (overshoot or undershoot) of the rotation speed Sr is detected, the gain Sg of the feedback control is further reduced, thereby making it possible to suppress subsequent fluctuations in the rotation speed Sr.

[0066] The control circuit 5 may change the designated value of the gain Sg to "G0" which is smaller than "G1", and then fix the designated value of the gain Sg to "G0" regardless of the magnitude of the deviation Sdf. This can further stabilize the rotation speed Sr. When the target rotation speed Stg is changed, the fixed value of the gain Sg is released.

[0067] Next, the flow of the gain adjustment process performed by the motor drive control device 2 according to the first embodiment will be described.

[0068] FIG. 4 is a flowchart showing the flow of the gain adjustment process performed by the motor drive control device 2 according to the first embodiment.

[0069] First, in the motor drive control device 2, the control circuit 5 acquires information on the rotation speed Sr of the motor 3 (step S1). Specifically, as described above, the rotation speed calculation unit 11 calculates the rotation speed Sr of the motor 3 based on the position detection signal Sh output from the position detector 4.

[0070] Next, the control circuit 5 acquires information on the target rotation speed Stg (step S2). Specifically, as described above, the drive command analysis unit 10 analyzes the drive command signal Sc to acquire information on the target rotation speed Stg.

[0071] Next, the control circuit 5 (transient response determination unit 16) determines whether the target rotation speed Stg is equal to or greater than a predetermined threshold value Sth (step S3). If the target rotation speed Stg is smaller than the predetermined threshold value Sth (step S3: NO), the control circuit 5 proceeds to step S6 without performing the transient response determination process described below.

[0072] On the other hand, if the target rotation speed Stg is equal to or greater than the predetermined threshold value Sth (step S3: YES), the control circuit 5 determines whether the motor 3 is accelerating or decelerating (step S4).

[0073] If the target rotation speed Stg has changed, the drive command analyzer 10 determines that the motor 3 is accelerating or decelerating (step S4: YES), and performs a transient response determination process (step S5). The flow of the transient response determination process in step S5 will be described later.

[0074] On the other hand, if the target rotation speed Stg has not changed, the drive command analysis unit 10 determines that the motor 3 is not accelerating or decelerating (step S4: NO), and proceeds to step S6 without performing the transient response determination process described below.

[0075] In step S6, the gain determiner 13 determines whether the absolute value |Sdf| of the deviation Sdf is equal to or less than α. If the absolute value |Sdf| of the deviation Sdf is equal to or less than α, the gain determiner 13 determines whether the designated value of the gain Sg set at that time is "G0" (step S7). If the designated value of the gain Sg is not equal to G0 (step S7: NO), the gain determiner 13 sets the designated value of the gain Sg to "G1" (step S9). On the other hand, if the designated value of the gain Sg is equal to G0 (step S7: YES), the gain determiner 13 maintains the designated value of the gain Sg as "G0".

[0076] In step S6, if the absolute value |Sdf| of the deviation Sdf is greater than α (step S6: NO), the gain determiner 13 determines whether the absolute value |Sdf| of the deviation Sdf is less than or equal to β (step S8). If the absolute value |Sdf| of the deviation Sdf is less than or equal to β (step S8: YES), the gain determiner 13 sets the designated value of the gain Sg to "G2" (step S10). On the other hand, if the absolute value |Sdf| of the deviation Sdf is greater than β (step S8: NO), the gain determiner 13 sets the designated value of the gain Sg to "G3" (step S11).

[0077] Next, the transient response determination process in step S5 will be described. FIG. 5 is a flowchart showing the flow of the transient response determination process (step S5).

[0078] In the transient response determination process (step S5), the transient response determination unit 16 of the control circuit 5 determines whether the polarity of the deviation Sdf (=Stg-Sr) calculated by the speed deviation calculation unit 12 has switched from positive (+) to negative (-) (step S51).

[0079] If the polarity of the deviation Sdf (=Stg-Sr) switches from positive to negative (step S51: YES), the transient response determination unit 16 determines whether the rotation speed Sr of the motor 3 is equal to or greater than (Stg+γ) (step S53).

[0080] If the rotation speed Sr of the motor 3 is smaller than (Stg+γ) (step S53: NO), the control circuit 5 ends the transient response determination process (step S5) and proceeds to step S6 in FIG. 4. On the other hand, if the rotation speed Sr of the motor 3 is equal to or greater than (Stg+γ) (step S53: YES), the transient response determination unit 16 determines that an overshoot of the rotation speed Sr relative to the target rotation speed Stg has occurred (step S55). In this case, the gain determination unit 13 sets the designated value of the gain Sg to "G0" (step S56). Thereafter, the control circuit 5 proceeds to step S6 in FIG. 4.

[0081] In step S51, if the polarity of the deviation Sdf (=Stg-Sr) has not switched from positive to negative (step S51: NO), the transient response determination unit 16 determines whether the polarity of the deviation Sdf (=Stg-Sr) has switched from negative to positive (step S52). If the polarity of the deviation Sdf (=Stg-Sr) has not switched from negative to positive (step S52: NO), the control circuit 5 ends the transient response determination process (step S5) and proceeds to step S6 in FIG.

[0082] If the polarity of the deviation Sdf (=Stg-Sr) switches from negative to positive (step S52: YES), the transient response determination unit 16 determines whether the rotation speed Sr of the motor 3 is equal to or lower than (Stg-γ) (step S54).

[0083] If the rotation speed Sr of the motor 3 is greater than (Stg-γ) (step S54: NO), the control circuit 5 ends the transient response determination process (step S5) and proceeds to step S6 in FIG. 4. On the other hand, if the rotation speed Sr of the motor 3 is equal to or less than (Stg-γ) (step S54: YES), the transient response determination unit 16 determines that an undershoot of the rotation speed Sr relative to the target rotation speed Stg has occurred (step S57). In this case, the gain determination unit 13 sets the designated value of the gain Sg to "G0" (step S58). Thereafter, the control circuit 5 proceeds to step S6 in FIG. 4. The gain adjustment process and the transient response determination process are executed according to the above-described processing procedures.

[0084] Next, the effects of the gain adjustment function in the motor drive control device 2 according to the first embodiment will be described.

[0085] FIG. 6 shows the change over time in the specified value of gain Sg and rotation speed Sr of motor drive control device 2 according to embodiment 1 during motor acceleration, and the change over time in the gain and rotation speed of feedback control of the prior art in which the gain is kept constant as a comparative example (for convenience, it is assumed that the gain of the comparative example is equivalent to the specified value G3 of gain Sg in the present invention).

[0086] In FIG. 6, reference numerals 51 and 61 respectively represent the gain Sg and the rotation speed Sr of the motor 3 in the motor drive control device 2 according to embodiment 1, and reference numerals 51A and 61A respectively represent the gain and the rotation speed of the motor when the gain is kept constant as in the prior art.

[0087] FIG. 7 shows the change over time in the specified value of gain Sg and rotation speed Sr of motor drive control device 2 according to embodiment 1 when the motor is decelerating, and the change over time in the gain and rotation speed of feedback control of the prior art in which the gain is kept constant as a comparative example (for convenience, it is assumed that the gain of the comparative example is equivalent to the specified value G3 of gain Sg in the present invention).

[0088] In FIG. 7, reference numerals 52 and 62 respectively represent the gain Sg and the rotation speed Sr of the motor 3 in the motor drive control device 2 according to embodiment 1, and reference numerals 52A and 62A respectively represent the gain and the rotation speed of the motor when the gain is kept constant as in the prior art.

[0089] As shown in FIGS. 6 and 7, in the case of the conventional technology in which the gain of the feedback control is fixed to a predetermined value, the overshoot and undershoot of the rotation speed becomes large when the motor is accelerating and decelerating.

[0090] In contrast, according to the motor drive control device 2 of embodiment 1, the smaller the deviation Sdf of the rotation speed Sr from the target rotation speed Stg, the smaller the gain Sg becomes. Therefore, as shown in Figures 6 and 7, it is possible to reduce overshoot and undershoot and improve the stability of the rotation speed Sr.

[0091] FIG. 8 shows the change over time in the specified value of gain Sg and rotation speed Sr of the motor drive control device 2 according to embodiment 1 when the motor 3 accelerates, and, as a comparative example, the change over time in the gain (for convenience, it is assumed that the gain of the conventional technology changes from the specified value G3 of the gain Sg of the present invention to the value G1) and rotation speed in a conventional technology that continuously changes the gain according to the deviation of the rotation speed.

[0092] In FIG. 8, reference numerals 53 and 63 respectively represent the gain Sg and the rotation speed Sr of the motor 3 in the motor drive control device according to embodiment 1, and reference numerals 53A and 63A respectively represent the gain and the rotation speed of the motor when the gain is continuously changed according to the deviation in the rotation speed as in the prior art.

[0093] FIG. 9 shows the change over time in the specified value of gain Sg and rotation speed Sr of the motor drive control device 2 according to embodiment 1 when the motor 3 is decelerating, and also shows the change over time in the gain (for convenience, it is assumed that the gain of the conventional technology changes from the specified value G3 of the gain Sg of the present invention to the value G1) and rotation speed of the conventional technology, which continuously changes the gain according to the deviation of the motor's rotation speed, as a comparative example.

[0094] In FIG. 9, reference symbols 54 and 64 respectively represent the gain Sg and the rotation speed Sr of the motor 3 in the motor drive control device 2 according to embodiment 1, and reference symbols 54A and 64A respectively represent the gain and the rotation speed of the motor when the gain is continuously changed according to the deviation in the rotation speed as in the prior art.

[0095] As shown in Figures 8 and 9, in the case of conventional technology in which the feedback control gain is continuously changed in response to the deviation, the overshoot and undershoot of the motor rotation speed are reduced, but the time it takes for the rotation speed to reach the target speed is lengthened.

[0096] In contrast, according to the motor drive control device 2 of embodiment 1, the gain Sg changes gradually (stepwise) according to the deviation Sdf, so that the rotation speed Sr can reach the target rotation speed Stg in a shorter time, as shown in Figures 8 and 9, and it is possible to improve both the stability and responsiveness of the rotation speed Sr of the motor 3.

[0097] FIG. 10 is a diagram showing temporal changes in the designated value of gain Sg and rotation speed Sr of motor drive control device 2 according to embodiment 1 when motor 3 is accelerating.

[0098] In Figure 10, reference symbols 55 and 65 represent the gain Sg and the rotation speed Sr of the motor 3, respectively, when the overshoot and undershoot of the rotation speed Sr is small in the motor drive control device 2 of embodiment 1, and reference symbols 55A and 65A represent the gain Sg and the rotation speed Sr of the motor 3, respectively, when the overshoot and undershoot of the rotation speed Sr is large in the motor drive control device 2 of embodiment 1.

[0099] FIG. 11 is a diagram showing temporal changes in the designated value of gain Sg and rotation speed Sr of motor drive control device 2 according to embodiment 1 when motor 3 is decelerating.

[0100] In FIG. 11, reference numerals 56 and 66 respectively represent the gain Sg and the rotation speed Sr of the motor 3 when the overshoot and undershoot of the rotation speed Sr is small in the motor drive control device 2 of embodiment 1, and reference numerals 56A and 66A respectively represent the gain and the rotation speed Sr of the motor 3 when the overshoot and undershoot of the rotation speed Sr is large in the motor drive control device 2 of embodiment 1.

[0101] As shown in Figures 10 and 11, with the motor drive control device 2 of embodiment 1, if a large overshoot occurs for some reason, the specified value of the gain Sg is set to "G0," which is even lower than "G1." This reduces subsequent overshoot and undershoot, making it possible to more quickly make the rotational speed Sr reach the target rotational speed Stg.

[0102] Figure 12 is a diagram showing the time-dependent changes in the specified value of the gain Sg of the motor drive control device 2 of embodiment 1 and the rotational speed Sr of the motor 3 when the rotational speed Sr changes after reaching the target rotational speed Stg.

[0103] In FIG. 12, reference numerals 57 and 67 respectively denote the designated value of gain Sg and rotation speed Sr of motor 3 in motor drive control device 2 according to the first embodiment.

[0104] For example, even if the rotation speed Sr changes due to load fluctuations on the motor 3, the motor drive control device 2 adjusts the specified value of the gain Sg according to the deviation Sdf of the rotation speed Sr, as shown in Figure 12, so that the rotation speed Sr can be stabilized at the target rotation speed Stg more quickly.

[0105] As described above, the motor drive control device 2 according to the first embodiment can improve both the stability and responsiveness of the rotation speed Sr of the motor 3 in speed control of the motor 3.

[0106] Second Embodiment FIG. 13 is a diagram showing the configuration of a motor unit 1A equipped with a motor drive control device 2A according to a second embodiment of the present invention.

[0107] 13, a gain determination unit 13A in a control circuit 5A has two gain tables (gain tables 21 and 22). Motor drive control device 2A differs from motor drive control device 2 according to embodiment 1 in that, by referencing the two gain tables, the rate of change in the designated value of gain Sg relative to the value of deviation Sdf of rotation speed Sr when motor 3 is accelerating differs from the rate of change in the designated value of gain Sg relative to the value of deviation Sdf of rotation speed Sr when motor 3 is decelerating; in other respects, motor drive control device 2A is similar to motor drive control device 2 according to embodiment 1.

[0108] FIG. 14 is a diagram illustrating the correspondence relationship between the rotation speed Sr of the motor 3 and the designated value of the gain Sg according to the second embodiment.

[0109] As shown in Figure 14, in the motor drive control device 2A of embodiment 2, the rate of change of the specified value of the gain Sg relative to the value of the deviation Sdf (=Stg-Sr) of the rotational speed Sr when the motor 3 is accelerating, i.e., in the range where the rotational speed Sr is smaller than the target rotational speed Stg, is different from the rate of change of the specified value of the gain Sg relative to the value of the deviation Sdf of the rotational speed Sr when the motor 3 is decelerating, i.e., in the range where the rotational speed Sr is larger than the target rotational speed Stg.

[0110] Specifically, the width of the division of the deviation Sdf in the range where the rotation speed Sr is smaller than the target rotation speed Stg (the range where the deviation Sdf is positive) is different from the width of the division of the deviation Sdf in the range where the rotation speed Sr is larger than the target rotation speed Stg (the range where the deviation Sdf is negative).

[0111] Also, the specified value of the gain Sg associated with the classification of the value of the deviation Sdf in the range where the rotational speed Sr is smaller than the target rotational speed Stg (the range where the deviation Sdf is positive) is different from the specified value of the gain Sg associated with the classification of the value of the deviation Sdf in the range where the rotational speed Sr is larger than the target rotational speed Stg (the range where the deviation Sdf is negative).

[0112] For example, the magnitude of the gain Sg during the acceleration of the motor 3 is set as follows. As shown in FIG. 14, when the value of the deviation Sdf of the rotational speed Sr is in the range of -αa ≦ Sdf < 0, that is, in the classification Ra1 of the deviation Sdf, "Ga1" is set as the specified value of the gain Sg. Also, when the value of the deviation Sdf of the rotational speed Sr is in the range of -βa ≦ Sdf < -αa, that is, in the classification Ra2 of the deviation Sdf, "Ga2" is set as the specified value of the gain Sg. Also, when the value of the deviation Sdf of the rotational speed Sr is in the range of Sdf < -βa, that is, in the classification Ra3 of the deviation Sdf, "Ga3" is set as the specified value of the gain Sg.

[0113] Also, for example, the magnitude of the gain Sg during the deceleration of the motor 3 is set as follows. As shown in FIG. 14, when the value of the deviation Sdf of the rotational speed Sr is in the range of 0 < Sdf ≦ αd, that is, in the classification Rd1 of the deviation Sdf, "Gd1" is set as the specified value of the gain Sg. Also, when the value of the deviation Sdf of the rotational speed Sr is in the range of αd < Sdf ≦ βd, that is, in the classification Rd2 of the deviation Sdf, "Gd2" is set as the specified value of the gain Sg. Also, when the value of the deviation Sdf of the rotational speed Sr is in the range of βd < Sdf, that is, in the classification Rd3 of the deviation Sdf, "Gd3" is set as the specified value of the gain Sg.

[0114] Here, the magnitude relationship of the specified values of the gain Sg is Gd1 < Gd2 < Gd3, Ga1 < Ga2 < Ga3. Also, for example, the relationship of the values of the deviation Sdf is αd ≠ αa, βd ≠ βa. Further, for example, the magnitude relationship of the specified values of the gain Sg is Ga1 < Gd1, Ga2 < Gd2, Ga3 < Gd3.

[0115] In the control circuit 5A according to the second embodiment, the gain determination unit 13A determines the magnitude of the gain Sg based on the correspondence relationship between the range (division) representing the magnitude of the deviation Sdf and the specified value of the gain Sg, as shown in FIG.

[0116] For example, as shown in FIG. 13, the gain determination unit 13A has a gain table 21 which is information indicating the correspondence between the range (division) representing the magnitude of the deviation Sdf and the specified value of the gain Sg when the motor 3 is accelerating (the range in which the deviation Sdf of the rotation speed is positive (+)), and a gain table 22 which is information indicating the correspondence between the range (division) representing the magnitude of the deviation Sdf and the specified value of the gain Sg when the motor 3 is decelerating (the range in which the deviation Sdf of the rotation speed Sr is negative (-)).

[0117] The gain determination unit 13A determines the magnitude of the gain Sg by referring to the gain tables 21 and 22 based on the deviation Sdf (=Stg−Sr) calculated by the speed deviation calculation unit 12.

[0118] FIG. 15 is a diagram showing an example of the gain table 21 when the motor 3 is accelerating according to the second embodiment. As shown in FIG. 15, the gain table 21 is a table that associates ranges (divisions) that indicate the magnitude of the deviation Sdf when the motor 3 is accelerating (the range in which the deviation Sdf of the rotation speed Sr is positive (+)) with designated values ​​of the gain Sg.

[0119] FIG. 16 is a diagram showing an example of the gain table 22 when the motor 3 is decelerating according to the second embodiment. As shown in FIG. 16, the gain table 22 is a table that associates ranges (divisions) that indicate the magnitude of the deviation Sdf when the motor 3 is decelerating (the range in which the deviation Sdf of the rotation speed Sr is negative (-)) with designated values ​​of the gain Sg.

[0120] When determining the magnitude of the gain Sg, the gain determination unit 13A reads out from the gain table 21 or the gain table 22 a designated value of the gain Sg corresponding to the value of the deviation Sdf calculated by the speed deviation calculation unit 12, and determines the read designated value as the magnitude of the gain Sg. For example, when the polarity of the value of the deviation Sdf is negative (-) and the absolute value |Sdf| of the deviation Sdf is greater than αd and equal to or less than βd, the gain determination unit 13A sets the designated value of the gain Sg to "Gd2."

[0121] Furthermore, in the motor drive control device 2A according to the second embodiment, the range (division) of the deviation Sdf, which is the criterion for determining the transient response of the motor 3 during acceleration, and the designated value of the gain Sg set for that division, may be different from the range (division) of the deviation Sdf, which is the criterion for determining the transient response of the motor 3 during acceleration, and the designated value of the gain Sg set for that division. That is, in Figures 14 to 16, the value γd of the deviation Sdf may be γa≠γa, and the designated value Gd0 of the gain Sg may be Ga0.

[0122] In this way, by differentiating the rate of change of the specified value of the gain Sg relative to the value of the deviation Sdf of the rotational speed Sr when the motor 3 is accelerating from the rate of change of the specified value of the gain Sg relative to the value of the deviation Sdf of the rotational speed Sr when the motor 3 is decelerating, it is possible to further improve the responsiveness of the rotational speed Sr.

[0123] For example, when the motor 3 is decelerating, the motor 3 is rotating by inertia, and therefore the responsiveness (tracking ability) to a deceleration command is lower than when an acceleration command is issued for the motor 3. Therefore, for example, the width of the section Rd2 of the deviation Sdf when the motor 3 is decelerating can be made wider than the width of the section Ra2 of the deviation Sdf when the motor 3 is accelerating, and the specified gain value "Gd2" for the section Rd2 when the motor 3 is decelerating can be made larger than the specified gain value "Ga2" for the section Ra2 when the motor 3 is accelerating, thereby improving the responsiveness of the rotational speed Sr to a deceleration command. This makes it possible to make the rotational speed Sr of the motor 3 reach the target rotational speed Stg more quickly, even when the motor 3 is decelerating.

[0124] <<Extension of Embodiment>> The invention made by the present inventors has been specifically described above based on an embodiment, but it goes without saying that the invention is not limited thereto and can be modified in various ways without departing from the spirit of the invention.

[0125] For example, in the above embodiment, the range of the deviation Sdf of the rotation speed Sr is divided into three sections on each of the positive side (high rotation speed side) and negative side (low rotation speed side) of the target rotation speed Stg. However, the number of sections may be two or more. For example, the greater the number of sections of the deviation Sdf, i.e., the greater the number of settings of the gain Sg, the more precisely the duty ratio of the PWM signal serving as the drive control signal Sd can be set during the process of changing the rotation speed Sr, thereby enabling better suppression of transient response (overshoot and undershoot). On the other hand, if the number of settings of the gain Sg is too large, the responsiveness of the rotation speed Sr will decrease (it will take longer for the rotation speed Sr to reach the target rotation speed Stg), and the drive control of the motor 3 will become more complicated. Therefore, the number of sections of the deviation Sdf (the number of settings of the gain Sg) is preferably 10 or less, and more preferably in the range of 2 to 5. Furthermore, the number of sections of the deviation Sdf of the rotation speed Sr provided on the positive side and the negative side with respect to the target rotation speed Stg does not necessarily have to be the same.

[0126] In the above embodiment, the type of motor 3 is not limited to a brushless DC motor. Also, the motor 3 is not limited to a three-phase motor, and may be, for example, a single-phase brushless DC motor.

[0127] In the above embodiment, a Hall element is used as the position detector 4, but this is not limiting. For example, a Hall IC, an encoder, a resolver, or the like may be provided as the position detector 4, and the detection signal thereof may be input to the motor drive control device 2, 2A as the position detection signal Sh. Furthermore, the motor drive control device 2, 2A may drive the motor 3 using a known position sensorless method without providing the position detector 4.

[0128] Furthermore, although an example has been given in which each functional unit of the control circuits 5 and 5A is realized by program processing of an MCU, this is not limited to this, and some or all of each functional unit of the control circuits 5 and 5A may be realized by a dedicated circuit (hardware).

[0129] Furthermore, the above-described flowcharts are merely examples and are not limited to these. For example, other processes may be inserted between each step, or the processes may be parallelized. [Explanation of symbols]

[0130] 1, 1A... motor unit, 2, 2A... motor drive control device, 3... motor, 4... position detector, 5, 5A... control circuit, 6... drive circuit, 10... drive command analysis unit, 11... rotation speed calculation unit, 12... speed deviation calculation unit, 13, 13A... gain determination unit, 14... operation amount calculation unit, 15... drive control signal generation unit, 16... transient response determination unit, Sc... drive command signal (speed command signal), Stg... target rotation speed, Sr... Rotation speed, Sdf...deviation, Str...transient response notification signal, Sg...gain, So...operated amount, Sd...drive control signal, Sh...position detection signal, Sth...threshold (of target rotation speed), 20~22...gain table, Rd1~Rd3, Ra1~Ra3...classification of deviation Sdf, G0~G3, Gd0~Gd3, Ga0~Ga3...specified gain value, α, αa, αd, β, βa, βd, γ, γa, γd...deviation value.

Claims

1. a drive circuit that applies a voltage to a coil of the motor to drive the motor based on a drive control signal for controlling the drive of the motor; a control circuit that performs feedback control to generate the drive control signal so that the rotation speed of the motor coincides with a target rotation speed, the control circuit changes the gain in a stepwise manner so that the gain of the feedback control decreases as the deviation of the rotation speed of the motor from the target rotation speed decreases; a designated value of the gain is set for each of a plurality of sections representing the magnitude of the deviation; the control circuit calculates the deviation, selects the designated value set for the category to which the calculated deviation belongs, and performs the feedback control based on the selected designated value; when it is determined that a transient response including at least one of an overshoot and an undershoot of the rotation speed of the motor with respect to the target rotation speed has occurred, the control circuit changes the gain to a value smaller than the designated value selected immediately before, and performs the feedback control; The control circuit performs a transient response determination process to determine whether or not the transient response has occurred when the target rotation speed is equal to or greater than a predetermined threshold value, and does not perform the transient response determination process when the target rotation speed is smaller than the predetermined threshold value. Motor drive control device.

2. a drive circuit that applies a voltage to a coil of the motor to drive the motor based on a drive control signal for controlling the drive of the motor; a control circuit that performs feedback control to generate the drive control signal so that the rotation speed of the motor coincides with a target rotation speed, the control circuit changes the gain in a stepwise manner so that the gain of the feedback control decreases as the deviation of the rotation speed of the motor from the target rotation speed decreases; a designated value of the gain is set for each of a plurality of sections representing the magnitude of the deviation; the control circuit calculates the deviation, selects the designated value set for the category to which the calculated deviation belongs, and performs the feedback control based on the selected designated value; when it is determined that a transient response including at least one of an overshoot and an undershoot of the rotation speed of the motor with respect to the target rotation speed has occurred, the control circuit changes the gain to a value smaller than the designated value selected immediately before, and performs the feedback control; The control circuit fixes the gain regardless of the calculated deviation when the gain is changed to a value smaller than the specified value, and releases the fixation of the gain when the target rotation speed is changed. Motor drive control device.

3. 3. The motor drive control device according to claim 1, A rate of change of the designated value with respect to the deviation in a range in which the rotation speed is smaller than the target rotation speed is different from a rate of change of the designated value with respect to the deviation in a range in which the rotation speed is larger than the target rotation speed. Motor drive control device.

4. 4. The motor drive control device according to claim 3, The width of the section in the range where the rotation speed is smaller than the target rotation speed is different from the width of the section in the range where the rotation speed is larger than the target rotation speed. Motor drive control device.

5. 5. The motor drive control device according to claim 3, The designated value associated with the range in which the rotation speed is smaller than the target rotation speed and the designated value associated with the range in which the rotation speed is larger than the target rotation speed are different from each other. Motor drive control device.

6. The motor drive control device according to any one of claims 1 to 5; the motor; Motor unit.

7. A motor drive control method for performing feedback control so that the rotation speed of a motor coincides with a target rotation speed, comprising: a first step of detecting a rotation speed of the motor; a second step of changing the gain of the feedback control in a stepwise manner so that the gain decreases as the deviation of the rotation speed detected in the first step from the target rotation speed decreases, a designated value of the gain is set for each of a plurality of sections representing the magnitude of the deviation; The second step is a third step of calculating the deviation, selecting the designated value set for the category to which the calculated deviation belongs, and performing the feedback control based on the selected designated value; a fourth step of performing a transient response determination process to determine whether or not a transient response has occurred when the target rotation speed is equal to or greater than a predetermined threshold value, and not performing the transient response determination process when the target rotation speed is smaller than the predetermined threshold value; a fifth step of changing the gain to a value smaller than the designated value selected immediately before and performing the feedback control when it is determined in the transient response determination process that a transient response including at least one of an overshoot and an undershoot of the rotation speed of the motor with respect to the target rotation speed has occurred. Motor drive control method.

8. A motor drive control method for performing feedback control so that the rotational speed of a motor coincides with a target rotational speed, comprising: a first step of detecting a rotation speed of the motor; a second step of changing the gain of the feedback control in a stepwise manner so that the gain decreases as the deviation of the rotation speed detected in the first step from the target rotation speed decreases, a designated value of the gain is set for each of a plurality of sections representing the magnitude of the deviation; The second step is a third step of calculating the deviation, selecting the designated value set for the category to which the calculated deviation belongs, and performing the feedback control based on the selected designated value; a fourth step of changing the gain to a value smaller than the designated value selected immediately before, when it is determined that a transient response including at least one of an overshoot and an undershoot of the rotation speed of the motor with respect to the target rotation speed has occurred, and performing the feedback control; a fifth step of fixing the gain regardless of the calculated deviation when the gain is changed to a value smaller than the specified value, and releasing the fixation of the gain when the target rotation speed is changed. Motor drive control method.

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