Motor drive controller and motor drive control method

Abstract

To suppress the heat generation and power consumption of a motor, and mechanical damage of a controller.SOLUTION: A motor drive controller 10 comprises: a position calculation unit 100 for calculating a current position of a rotor of a motor 11 based on the output of a position sensor 14; a position control unit 101 for calculating a positional deviation amount between a target stop position of the rotor and the current position calculated by the position calculation unit 100, determining the magnitude of a current to be applied to the motor 11 based on the positional deviation amount, and outputting a control signal; and an inverter circuit 103 for supplying the current to the motor 11 according to the control signal. The position control unit 101 determines the magnitude of the current to be applied to the motor 11 to be a specified value smaller than a maximum allowable current when the positional deviation amount is within a dead zone, and determines the magnitude of the current to be applied to the motor 11 to be a value corresponding to the magnitude of the positional deviation amount when the positional deviation amount is out of the dead zone.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Research and development is being conducted on technologies for stopping a motor rotor at a target stop position. A technology has been proposed for a control device for a three-phase brushless motor, in which after rotating the motor rotor to a target stop position, the rotor's rotational position is held stationary by single-phase energization, which energizes only one of the motor's U, V, or W phases (see Patent Document 1). Here, single-phase energization refers to energized braking. Single-phase energization generates a control force by passing a drive current through only one of the motor's U, V, or W phases within a braking range centered on the target stop position, as shown in Figure 7.

[0003] On the other hand, Patent Document 2 discloses a control device that, after performing control to rotate the rotor of a motor to a target stop position, does not pass current if the rotor is not deviated from the target stop position, but passes current according to the load that caused the deviation if the rotor is deviated from the target stop position, thereby maintaining the rotor position (Fig. 8). In the example of Fig. 8, no current passes through the motor within a predetermined range centered on the target stop position.

[0004] The technology disclosed in Patent Document 1 can maintain the position of the rotor, but has the problem of increasing heat generation and power consumption in the motor because a drive current is passed that takes into account the greatest external force. The technology disclosed in Patent Document 2 has the problem that, because current is applied only after rotor misalignment is detected, braking force cannot be generated until the misalignment is detected, and rotor movement below the misalignment detection resolution cannot be suppressed. Furthermore, the technology disclosed in Patent Document 2 has the problem that, because current is applied to the motor based on a table that associates positional misalignment with torque, data must be acquired at each point in advance to create the table. Furthermore, the technology disclosed in Patent Document 2 has the problem that, because current is suddenly applied from a state of zero braking torque to generate torque, there is a possibility that shocks may occur due to the sudden generation of torque, depending on the settings. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-075376 [Patent Document 2] International Publication WO2023 / 276593 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a motor drive control device and a motor drive control method that can reduce heat generation and power consumption of the motor and mechanical damage to the device. [Means for solving the problem]

[0007] The motor drive control device of the present invention comprises a position calculation unit configured to calculate the current position of the rotor of the motor based on the output of a position sensor attached to the motor; a position control unit configured to calculate the amount of positional deviation between the target stop position of the rotor and the current position calculated by the position calculation unit, determine the magnitude of the current to be passed to the motor based on the calculated amount of positional deviation, and output a control signal; and an inverter circuit configured to supply current to the motor in accordance with the control signal, wherein the position control unit determines the magnitude of the current to be passed to the motor to a predetermined value smaller than the maximum allowable current of the motor when the amount of positional deviation is within a dead band, and determines the magnitude of the current to be passed to the motor to a value corresponding to the amount of positional deviation when the amount of positional deviation is outside the dead band, thereby generating a braking torque that keeps the amount of positional deviation within an allowable range of positional deviation.

[0008] Furthermore, in one configuration example of the motor drive control device of the present invention, when the amount of positional deviation falls outside the dead band, the position control unit calculates the magnitude of the current to be passed through the motor using a linear equation determined by the amount of positional deviation, the predetermined value, the dead band, and a proportionality coefficient, and when the calculated current magnitude becomes equal to or exceeds the maximum allowable current, limits the magnitude of the current to be passed through the motor so that it is equal to the maximum allowable current. In one configuration example of the motor drive control device of the present invention, the position control unit counts the number of times that the position deviation amount deviates from the dead band after the amount of position deviation first enters the dead band to the point where the current flowing through the motor becomes the maximum allowable current, and when the counted number reaches a predetermined number, increases the proportionality coefficient by a predetermined change amount.

[0009] Furthermore, the motor drive control method of the present invention includes a first step of calculating a current position of the rotor of the motor based on the output of a position sensor attached to the motor, and a second step of calculating a positional deviation between a target stop position of the rotor and the current position calculated in the first step, determining a magnitude of a current to be passed through the motor based on the calculated positional deviation, and outputting a control signal, wherein the second step includes a step of determining the magnitude of the current to be passed through the motor to a predetermined value smaller than the maximum allowable current of the motor when the positional deviation amount is within a dead band, and determining the magnitude of the current to be passed through the motor to a value corresponding to the magnitude of the positional deviation amount when the positional deviation amount is outside the dead band, thereby generating a braking torque that keeps the positional deviation amount within the allowable positional deviation range.

[0010] In one configuration example of the motor drive control method of the present invention, the second step is characterized by including a step of calculating, when the amount of positional deviation falls outside the dead band, the magnitude of the current to be passed through the motor using a linear equation determined by the amount of positional deviation, the predetermined value, the dead band, and a proportionality coefficient, and, when the calculated magnitude of the current becomes equal to or exceeds the maximum allowable current, limiting the magnitude of the current to be passed through the motor so that it is equal to the maximum allowable current. In one configuration example of the motor drive control method of the present invention, the second step includes a step of counting the number of times that the positional deviation amount deviates from the dead band after the positional deviation amount first enters the dead band until the current flowing through the motor becomes the maximum allowable current, and increasing the proportionality coefficient by a predetermined change amount when the counted number reaches a predetermined number. [Effects of the Invention]

[0011] According to the present invention, current flows through the motor even when the positional deviation is within the dead zone. This allows for the generation of braking torque even in areas below the resolution where positional deviation cannot be detected, thereby suppressing rotor position fluctuations due to external forces. In this invention, by setting a small current value when the positional deviation is within the dead zone, heat generation and power consumption of the motor can be reduced. Furthermore, this invention allows the numerical values ​​for determining the current value to be passed through the motor to be determined through theoretical considerations alone, significantly reducing the need for prior measurement. Furthermore, since this invention generates braking torque even when the positional deviation is within the dead zone, when the positional deviation becomes large, the braking torque is increased from a state in which braking torque is already being generated. This reduces the occurrence of shocks due to changes in motor torque and suppresses mechanical damage to the device.

[0012] Furthermore, the present invention counts the number of times that the positional deviation amount deviates from the range in which the current flowing through the motor becomes the maximum allowable current after the amount of positional deviation first enters the dead band, and when the count reaches a predetermined number, increases the proportionality coefficient by a predetermined change amount.In this way, in an environment in which the external force causing rotor positional deviation is small, power consumption can be kept low by maintaining the value of the proportionality coefficient, and in an environment in which the external force is large, rotor positional deviation can be suppressed by increasing the proportionality coefficient. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing the configuration of a motor drive control device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart illustrating the operation of the motor drive control device according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the relationship between the amount of rotor positional deviation and the current flowing through the three-phase brushless motor in the first embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart illustrating the operation of the motor drive control device according to the second embodiment of the present invention. [Figure 5]FIG. 5 is a diagram showing the relationship between the amount of rotor positional deviation and the current flowing through the three-phase brushless motor in the second embodiment of the present invention. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a computer that realizes the motor drive control device according to the first and second embodiments of the present invention. [Figure 7] FIG. 7 is a diagram illustrating conventional single-phase current supply. [Figure 8] FIG. 8 is a diagram illustrating another conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0014] [First Example] Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a motor drive control device according to a first embodiment of the present invention. In the example of FIG. 1, a motor drive control device 10 is provided in an actuator device 1 that rotates a rotating body 2. The motor drive control device 10 drives a three-phase brushless motor 11. The rotation of the three-phase brushless motor 11 is transmitted to an output shaft 13 of the actuator device 1 via a mechanical component 12, causing the rotating body 2 attached to the output shaft 13 to rotate. A setter 3 sets a target stop position for the three-phase brushless motor 11. A power supply device 4 supplies a DC power supply voltage to the motor drive control device 10.

[0015] The motor drive control device 10 includes a position calculation unit 100, a position control unit 101, a storage unit 102, and an inverter circuit 103.

[0016] 2 is a flowchart illustrating the operation of the motor drive control device 10 of this embodiment. The setting device 3 sets a target stop position (angle) of the rotor of the three-phase brushless motor 11 for the actuator device 1 (step S100 in FIG. 2).

[0017] A position sensor 14 is attached to the three-phase brushless motor 11 to detect the rotational position of the rotor of the motor 11. An example of the position sensor 14 is a three-phase Hall sensor. The position calculation unit 100 of the motor drive control device 10 calculates the rotational position of the rotor of the three-phase brushless motor 11 based on the output signal of the position sensor 14 (step S101 in FIG. 2).

[0018] Next, position control unit 101 of motor drive control device 10 calculates the amount of positional deviation between the target stop position set by setter 3 and the current rotational position of the rotor calculated by position calculation unit 100, and determines the magnitude of current (duty ratio of the PWM signal) to be passed through each coil of the U, V, and W phases of three-phase brushless motor 11 based on the calculated amount of positional deviation (step S102 in FIG. 2), and outputs control signals for each of the U, V, and W phases to inverter circuit 103 so that a current of the determined magnitude flows (step S103 in FIG. 2).

[0019] 3 shows the relationship between the amount of rotor positional deviation from the target stop position and the current flowing through three-phase brushless motor 11. The relationship between the amount of rotor positional deviation (angle) and the current flowing through three-phase brushless motor 11 is determined by the maximum allowable current of three-phase brushless motor 11, a predetermined current smaller than the maximum allowable current, a dead band for the amount of positional deviation, and a proportionality coefficient. Specifically, if the amount of positional deviation is x, the predetermined current is I1, the width of the dead band is W, and the proportionality coefficient is a, the current I flowing through three-phase brushless motor 11 is determined by a linear equation such as equation (1) when the amount of positional deviation x, which is the difference between the target stop position and the current rotational position of the rotor, is positive. I=a{x-(W / 2)}+I1 (1)

[0020] On the other hand, when the positional deviation x is negative, the current I is determined by a linear equation such as equation (2). I=a{x+(W / 2)}+I1 (2)

[0021] When the positional deviation amount x is within the dead zone, one-phase current is applied to the coil of only one of the U, V, and W phases, with a predetermined current I=I1. In addition, in either case of equation (1) or equation (2), the value of the current I calculated is equal to or less than the maximum allowable current I of the three-phase brushless motor 11. max At this point, I=I maxThe maximum allowable current I max , the predetermined current I1, the width W of the dead zone, and the proportionality coefficient a are stored in advance in the storage unit 102. In this manner, the position control unit 101 can determine the magnitude of the current I.

[0022] In response to the control signal output from position control unit 101, inverter circuit 103 of motor drive control device 10 converts the DC current supplied from power supply device 4 into a three-phase current (or three-phase drive current), and supplies the three-phase current (or three-phase drive current) to the U-phase, V-phase, and W-phase coils of three-phase brushless motor 11. Inverter circuit 103 is composed of switching elements that are turned ON / OFF in response to the control signal output from position control unit 101. In this way, three-phase brushless motor 11 rotates so that the rotor of three-phase brushless motor 11 reaches a target stop position.

[0023] The rotation direction of three-phase brushless motor 11 may be appropriately determined based on the relationship between the target stop position and the current position calculated by position calculation unit 100. Furthermore, the driving method in which position control unit 101 switches the currents flowing through the coils of the U, V, and W phases of three-phase brushless motor 11 to rotate three-phase brushless motor 11 is a well-known technique, and therefore a detailed description thereof will be omitted.

[0024] Next, the process returns to step S101, and the current position of the rotor of the three-phase brushless motor 11 is calculated again. In this way, the processes of steps S101 to S103 are repeatedly executed until the driving of three-phase brushless motor 11 is completed or a new target stop position is set.

[0025] In this embodiment, while no positional deviation of the rotor from the target stop position is detected, one phase is energized with a small predetermined current I1, and after a positional deviation is detected, a current I proportional to the magnitude of the positional deviation is passed through the three-phase brushless motor 11 to generate a braking force. In this embodiment, because current is passed through the three-phase brushless motor 11 even when no positional deviation is detected, braking torque can be generated even in an area below the resolution where positional deviation cannot be detected, and positional fluctuation of the rotor (rotating body 2) due to external forces can be suppressed. In this embodiment, by setting the value of the predetermined current I1 to a small value, heat generation and power consumption of the three-phase brushless motor 11 can be suppressed.

[0026] In addition, to determine the current value to be applied to the three-phase brushless motor 11, the maximum allowable current I max All that is required is the specified current I1, the width of the dead band W, and the proportional coefficient a. All of these values ​​can be determined through desk studies alone, which can significantly reduce the need for prior measurements. In addition, the maximum allowable current I max Only one point may be measured in advance.

[0027] Furthermore, in this embodiment, braking torque is generated even when no positional deviation is detected, so that if the positional deviation becomes large, the braking torque is increased from the state in which braking torque is already being generated, making it less likely that an impact will occur due to a change in the torque of the three-phase brushless motor 11, and reducing mechanical damage to the actuator device 1.

[0028] [Second Example] Next, a second embodiment of the present invention will be described. In the first embodiment, the relationship between the amount of positional deviation x of the rotor from the target stop position and the current I flowing through the three-phase brushless motor 11 was fixed, but this relationship may be changed. In this embodiment, the configurations of the actuator device 1 and the motor drive control device 10 are the same as in the first embodiment, so the description will use the symbols in Figure 1.

[0029] 4 is a flowchart illustrating the operation of the motor drive control device 10 of this embodiment. The processing of steps S100 and S101 in FIG. 4 is the same as that described in the first embodiment. The position control unit 101 detects when the positional deviation x first enters the dead zone as the three-phase brushless motor 11 rotates and the current I reaches the maximum allowable current I max The number of times that the positional deviation x is out of range is counted until the current I reaches the maximum allowable current I after the positional deviation x first enters the dead zone. max If the current I is out of the range, the count value will be 1, and the current I will reach the maximum allowable current I max After the current I becomes smaller than the maximum allowable current I max If you miss the target until it reaches the target, the count value will be 2. After that, the counting will continue in the same way.

[0030] When the count reaches a predetermined number (YES in step S105 in FIG. 4), position control unit 101 changes the value of proportionality coefficient a so that it increases by a predetermined change amount (step S106 in FIG. 4). Position control unit 101 then determines the magnitude of current I (duty ratio of the PWM signal) to be flowed through three-phase brushless motor 11 using equation (1) or (2) based on the positional deviation amount x and proportionality coefficient a (step S102 in FIG. 4), and outputs control signals for the U-phase, V-phase, and W-phase to inverter circuit 103 so that a current of the determined magnitude flows (step S103 in FIG. 4).

[0031] In this embodiment, by increasing the proportionality coefficient a, the relationship between the positional deviation amount x and the current I is changed from the characteristic 200 (the characteristic of the first embodiment) shown in Fig. 5 to the characteristic 201. In this embodiment, in an environment where the external force that causes the rotor (rotating body 2) to be misaligned is small, power consumption can be kept low by maintaining the value of the proportionality coefficient a, and in an environment where the external force is large, the proportionality coefficient a can be increased to suppress the positional deviation of the rotor (rotating body 2).

[0032] The proportionality coefficient a may be changed only once or multiple times. That is, every time the number of times counted by the position control unit 101 increases by a predetermined number, the determination in step S105 may be YES, and the proportionality coefficient a may be increased by a predetermined change amount in step S106.

[0033] Furthermore, when the positional deviation amount x remains within the dead zone for a certain period of time or longer, the proportional coefficient a may be returned to the initial value stored in the memory unit 102, and the number of times counted by the position control unit 101 may be reset to 0.

[0034] The position calculation unit 100, position control unit 101, and storage unit 102 described in the first and second embodiments can be realized by a computer equipped with a CPU (Central Processing Unit), a storage device, and an interface, and a program that controls these hardware resources. An example of the configuration of this computer is shown in Figure 6.

[0035] The computer includes a CPU 300, a storage device 301, and an interface device (I / F) 302. The I / F 302 is connected to the hardware of the inverter circuit 103, the setting device 3, etc. In such a computer, a program for realizing the drive control method of the present invention is stored in the storage device 301. The CPU 300 executes the processes described in the first and second embodiments in accordance with the program stored in the storage device 301. [Industrial Applicability]

[0036] The present invention can be applied to, for example, a technique for stopping the rotor of a three-phase brushless motor at a target stop position. [Explanation of symbols]

[0037] 1...actuator device, 2...rotating body, 3...setting device, 4...power supply device, 10...motor drive control device, 11...three-phase brushless motor, 12...mechanism component, 13...output shaft, 14...position sensor, 100...position calculation unit, 101...position control unit, 102...memory unit, 103...inverter circuit

Claims

1. a position calculation unit configured to calculate a current position of a rotor of the motor based on an output of a position sensor attached to the motor; a position control unit configured to calculate a positional deviation between a target stop position of the rotor and the current position calculated by the position calculation unit, determine a magnitude of a current to be passed through the motor based on the calculated positional deviation, and output a control signal; an inverter circuit configured to supply a current to the motor in response to the control signal; a position control unit that, when the amount of positional deviation is within a dead zone, determines the magnitude of the current to be passed through the motor to a predetermined value smaller than the maximum allowable current of the motor, and, when the amount of positional deviation is outside the dead zone, determines the magnitude of the current to be passed through the motor to a value corresponding to the amount of positional deviation, thereby generating a braking torque that keeps the amount of positional deviation within an allowable range of positional deviation.

2. 2. The motor drive control device according to claim 1, a motor drive control device, characterized in that, when the amount of positional deviation falls outside the dead band, the position control unit calculates the magnitude of the current to be passed through the motor using a linear equation determined by the amount of positional deviation, the predetermined value, the dead band, and a proportionality coefficient, and, when the calculated current magnitude becomes equal to or greater than the maximum allowable current, limits the magnitude of the current to be passed through the motor so that it is equal to the maximum allowable current.

3. 3. The motor drive control device according to claim 2, the position control unit counts the number of times that the amount of positional deviation falls outside the dead band after the amount of positional deviation first falls within the dead band until the current flowing through the motor becomes the maximum allowable current, and when the counted number reaches a predetermined number, increases the proportionality coefficient by a predetermined change amount.

4. a first step of calculating a current position of a rotor of the motor based on an output of a position sensor attached to the motor; a second step of calculating a positional deviation between a target stop position of the rotor and the current position calculated in the first step, determining a magnitude of a current to be passed through the motor based on the calculated positional deviation, and outputting a control signal; the second step includes a step of determining the magnitude of the current to be passed through the motor to a predetermined value smaller than the maximum allowable current of the motor when the amount of positional deviation is within a dead zone, and determining the magnitude of the current to be passed through the motor to a value corresponding to the amount of positional deviation when the amount of positional deviation is outside the dead zone, thereby generating a braking torque that keeps the amount of positional deviation within the allowable range of positional deviation.

5. 5. The motor drive control method according to claim 4, a second step of calculating, when the amount of positional deviation falls outside the dead band, a magnitude of a current to be passed through the motor using a linear equation determined by the amount of positional deviation, the predetermined value, the dead band, and a proportionality coefficient, and, when the calculated magnitude of the current becomes equal to or greater than the maximum allowable current, limiting the magnitude of the current to be passed through the motor so that it is equal to the maximum allowable current.

6. 6. The motor drive control method according to claim 5, the second step includes a step of counting the number of times that the amount of positional deviation falls outside the dead band after the amount of positional deviation first falls within the dead band until the current flowing through the motor becomes the maximum allowable current, and increasing the proportionality coefficient by a predetermined change amount when the counted number reaches a predetermined number.

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