Motor drive device and motor drive method

Abstract

To provide a motor driving device and a motor driving method that can improve the followability of a drive current to a transient control signal.SOLUTION: A motor drive device that controls and outputs a drive current according to an external control signal includes a drive current output unit that outputs a drive current to a motor, a feedback control unit that controls the operation of the drive current output unit on the basis of a current target value specified by the control signal and a current output value output from the drive current output unit, and a gain setting unit that sets the control gain of the feedback control unit on the basis of the deviation between the current target value and the current output value and the amount of change in the current target value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a motor drive device and a motor drive method. [Background technology]

[0002] Conventionally, motor drive devices are known that control the drive current according to a control signal from a motor control device and output it to the motor (see, for example, Patent Document 1). The motor control device detects the drive state of the motor based on the output of a sensor or the like, and sends a control signal to the motor drive device to instruct a target value for the drive current (hereinafter referred to as the "target current value") so that the motor reaches a desired drive state.

[0003] In motor drive systems, for example, so-called feedback control is performed to control the operation of the drive current output section based on the current target value indicated by the control signal and the current drive current output value (hereinafter referred to as the "current output value"). Generally, when feedback control is performed, the control gain is fixed to one value. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-75962 [Overview of the project] [Problems that the invention aims to solve]

[0005] Motor drive systems are required to output drive current in a manner that accurately follows the input control signal. However, with typical feedback control systems where the control gain is fixed, it is difficult to achieve both high response speed and improved stability when transient control signals with changing current target values ​​are input.

[0006] For example, when the control gain is set to a high value, the responsiveness to a control signal is improved, but overshoot and oscillation are likely to occur, resulting in decreased stability (see FIG. 4C). On the other hand, when the control gain is set to a low value, the above problem is less likely to occur, but the responsiveness to a control signal deteriorates (see FIG. 4B).

[0007] An object of the present disclosure is to provide a motor driving device and a motor driving method capable of improving the followability of a drive current to a transient control signal. [[Means for Solving the Problem]]

[0008] The motor driving device according to the present disclosure includes: A motor driving device that controls and outputs a drive current in accordance with an external control signal, the motor driving device comprising: a drive current output unit that outputs said drive current to said motor; a feedback control unit that controls an operation of said drive current output unit based on a target current value instructed by said control signal and an output current value output from said drive current output unit; and a gain setting unit that sets a control gain of said feedback control unit based on an amount of change in said target current value and a deviation between said target current value and said output current value.

[0009] The motor driving method according to the present disclosure is: A motor driving method of controlling and outputting a drive current in accordance with an external control signal, the motor driving method comprising: a first step of outputting said drive current to said motor; a second step of performing feedback control on said first step based on a target current value instructed by said control signal and an output current value output in said first step, wherein said second step includes a step of setting a control gain based on an amount of change in said target current value and a deviation between said target current value and said output current value. [[Effects of the Invention]]

[0010] According to the motor drive device and motor drive method described herein, it is possible to improve the responsiveness of the drive current to transient control signals. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a diagram showing the schematic configuration of a motor drive device according to an embodiment. [Figure 2] Figure 2 shows an example of a gain setting table. [Figure 3] Figure 3 is a timing chart showing an example of the control gains that are set. [Figure 4] Figures 4A to 4C show the tracking performance of the drive current in response to the control signal (CMD). [Modes for carrying out the invention]

[0012] Embodiments of this disclosure will be described in detail below with reference to the drawings.

[0013] Figure 1 is a diagram showing the schematic configuration of a motor drive device 1 according to one embodiment of the present disclosure.

[0014] As shown in Figure 1, the motor drive unit 1 has a drive current output unit 10 and a drive current control unit 20. The drive current output unit 10 converts the input voltage from the power supply and outputs a drive current to the motor 101. The drive current control unit 20 controls the operation of the drive current output unit 10 according to the control signal CMD from the controller 102.

[0015] Motor 101 is, for example, a single-phase DC motor. Motor 101 may be a rotary motor or a linear motor. Motor 101 operates in a driving direction and driving speed corresponding to the direction and magnitude of the drive current supplied from the motor drive unit 1.

[0016] The controller 102 detects the driving state of the motor 101 based on the output of a sensor or the like attached to the motor 101, and sends a control signal CMD to the motor drive unit 1 so that the motor 101 enters the desired driving state.

[0017] The drive current output unit 10 includes a switching circuit 11, an output filter circuit 12, a current detection unit 13, and a gate drive circuit 14, etc.

[0018] The switching circuit 11 is composed of, for example, a full-bridge circuit (also called an H-bridge circuit) having four switching elements (e.g., MOSFETs). The output current can be controlled by alternately conducting two sets of switching elements arranged diagonally across the full-bridge circuit and by varying the ON pulse width.

[0019] The output filter circuit 12 includes, for example, an inductor and a capacitor. The output filter circuit 12 smooths the current output from the switching circuit 11 and outputs a drive current to the motor 101. Note that the output filter circuit 12 may be omitted depending on the circuit configuration.

[0020] The current detection unit 13 detects the current output value I0 of the drive current and outputs it to the PID control unit 21.

[0021] The gate drive circuit 14 controls the on / off state of the switching elements of the switching circuit 11 based on the drive signal PWM signal from the PWM control unit 22.

[0022] The drive current control unit 20 includes, as functional modules, a PID control unit 21, a PWM control unit 22, and a gain setting unit 23. The drive current control unit 20 is composed of a known microcontroller control circuit, which includes, for example, a CPU (Central Processing Unit) as an arithmetic / control device, and ROM (Read Only Memory) and RAM (Random Access Memory) as main memory. The CPU, for example, reads a program corresponding to the processing content from ROM, expands it into RAM, and executes the expanded program to realize each functional module of the drive current control unit 20.

[0023] Furthermore, some or all of the functional modules of the drive current control unit 20 may be composed of electronic circuits such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), or PLD (Programmable Logic Device) provided according to the processing.

[0024] The PID control unit 21 receives the current output value I0 detected by the current detection unit 13 and the current target value I indicated by the control signal CMD from the controller 102. cmd Based on this, the current output value I0 and the current target value I cmd The manipulated variable C for PWM control is calculated so that it matches the given value, and this value is output to the PWM control unit 22.

[0025] The PID control unit 21 controls the current target value I cmd The system performs proportional control (P), which controls the manipulated variable C in proportion to the difference (deviation e) between the current output value I0; integral control (I), which controls the manipulated variable C by accumulating the deviation e over time; and differential control (D), which controls the manipulated variable C according to the change in the deviation e.

[0026] The control gains in the PID control unit 21 include a proportional gain used for proportional control, an integral gain used for integral control, and a differential gain used for differential control.

[0027] The PWM control unit 22 calculates a duty ratio based on the manipulated variable C output from the PID control unit 21, generates a drive signal PWM having the duty ratio, and outputs the generated drive signal PWM to the gate drive circuit 14.

[0028] The gain setting unit 23 includes a deviation calculation unit 231, a change amount calculation unit 232, and a gain determination unit 233. The gain setting unit 23 sets the control gain G used in the PID control unit 21, that is, proportional gain, integral gain, and derivative gain. In contrast to the conventional case where the control gain G is fixed to one constant value, in the present embodiment, the control gain G can be changed.

[0029] In the gain setting unit 23, the deviation calculation unit 231 calculates a deviation e between a target current value I cmd and an output current value I0. The change amount calculation unit 232 calculates a change amount ΔI per unit time of the target current value I cmd , the change amount ΔI cmd is calculated. The change amount ΔI cmd is represented by the slope of the target current value I cmd . The gain determination unit 233 sets the control gain G based on the deviation e calculated by the deviation calculation unit 231 and the change amount ΔI calculated by the change amount calculation unit 232 cmd .

[0030] Specifically, the gain determination unit 233 sets the control gain G to be higher as the change amount ΔI cmd and the deviation e are larger. Further, the gain determination unit 233 sets the control gain G to be lower as the change amount ΔI cmd and the deviation e are smaller. That is, when the change amount ΔI cmd and the deviation e are large, the gain determination unit 233 sets the control gain G with emphasis on responsiveness to the control signal CMD, and when the change amount ΔI cmd and the deviation e are small, the gain determination unit 233 sets the control gain G with emphasis on the stability of the output current value I0. The determination of the control gain G by the gain determination unit 233 is performed, for example, with reference to the gain setting table shown in FIG. 2.

[0031] In the gain setting table shown in Figure 2, the range of change is divided by multiple change thresholds X0, X1, ... Also, the deviation range is divided by multiple deviation thresholds Y0, Y1, ... And the change amount ΔI cmd The gain setting value G(X,Y) is set in correspondence with the combination of the range of change to which the variable belongs and the range of deviation e belongs. The gain setting value G(X,Y) is the change amount ΔI cmd Furthermore, the larger the deviation e, the higher the value is set.

[0032] The controller 102 sends a current target value I to the motor drive unit 1. cmd An example of the control gain G set when a transient control signal CMD is input is explained using Figure 3. Figure 3 shows the current target value I being set to the motor drive unit 1. cmd When the control signal CMD is input, the current output value I0 and the change in the current target value ΔI cmd , Current target value I cmd The relationship between the difference (deviation e) between the current output value I0 and the set control gain G is shown.

[0033] In Figure 3, the target current value I cmd This is a constant change ΔI from timing T0 to timing T2. cmd It increases, and remains constant after timing T2. For example, when the controller 102 detects an increase in torque in the motor 101, it sets the current target value I as shown in Figure 3. cmd This instructs the system to increase the drive current by increasing the value.

[0034] At timing T0 to T1, the change amount ΔI cmd The variable is constant and falls within the range of change X1 to X2. The deviation e falls within the deviation range Y0 to Y1. Referring to the gain setting table in Figure 2, the control gain G is set to G(X1,Y0).

[0035] At timings T1 to T2, the change amount ΔI cmdThe variable is constant and falls within the range of change X1 to X2. The deviation e also falls within the deviation range Y1 to Y2. Referring to the gain setting table in Figure 2, the control gain G is set to G(X1,Y1). Since the gain setting value G(X1,Y1) is higher than the gain setting value G(X1,Y0), control that prioritizes responsiveness is performed.

[0036] At timings T2 to T3, the change ΔI cmd The value of ΔI is 0 and falls within the range of change X0 to X1. The deviation e falls within the range of deviation Y1 to Y2. Referring to the gain setting table in Figure 2, the control gain G is set to G(X0,Y1). Since the gain setting value G(X0,Y1) is lower than the gain setting value G(X1,Y1), control prioritizing stability is performed. That is, the change amount ΔI cmd After the deviation becomes 0, the deviation e converges, so stability is prioritized over responsiveness to suppress overshoot and oscillation.

[0037] At timings T3 to T4, the change amount ΔI cmd The value is 0 and belongs to the change range X0 to X1. Also, the deviation e belongs to the deviation range Y0 to Y1. Referring to the gain setting table in Figure 2, the control gain G is set to G(X0,Y0). Since the gain setting value G(X0,Y0) is lower than the gain setting value G(X0,Y1), control that prioritizes stability is performed. In other words, after the deviation e falls below the threshold Y1, the current output value I0 becomes the current target value I cmd To match this, stability is given even greater emphasis.

[0038] Figure 4 shows the control signal CMD (current target value I cmd This figure shows the responsiveness of the drive current to ). Figure 4A shows the current control according to the embodiment, i.e., the change amount ΔI cmd The figures also show the tracking performance when current control is performed by setting the control gain G based on the deviation e. Figure 4B shows the case when the control gain G is fixed at a low value, and Figure 4C shows the case when the control gain G is fixed at a high value.

[0039] When the control gain G is fixed at a low value, as shown in Figure 4B, the current output value I0 is equal to the current target value I cmd It takes time to reach this point, and the response to the control signal CMD is poor. Also, when the control gain G is fixed at a high value, as shown in Figure 4C, the response speed is fast, but overshoot and oscillation are more likely to occur, and stability decreases. In contrast, the change amount ΔI cmd And when the control gain G is appropriately adjusted based on the deviation e, as shown in Figure 4A, both the responsiveness and stability of the drive current can be achieved, and the control signal CMD (current target value I cmd The ability to follow ) is significantly improved.

[0040] As described above, the motor drive device 1 and motor drive method according to the embodiment are equipped with the following features individually or in appropriate combinations.

[0041] In other words, the motor drive unit 1 is a motor drive unit that controls and outputs a drive current according to a control signal CMD from a controller 102 (external), and includes a drive current output unit 10 that outputs a drive current to the motor 101, and a current target value I indicated by the control signal CMD. cmd Based on the current output value I0 output from the drive current output unit 10, the PID control unit 21 (feedback control unit) controls the operation of the drive current output unit 10, and the change amount ΔI of the current target value cmd , and the target current value I cmd The system includes a gain setting unit 23 that sets the control gain G of the PID control unit 21 based on the deviation e between the current output value I and the current output value I.

[0042] Furthermore, the motor driving method according to the embodiment is a motor driving method that controls and outputs a drive current according to a control signal CMD from a controller 102 (external), and comprises a first step of outputting a drive current to the motor (operation of the drive current output unit 10), and a current target value I instructed by the control signal CMD. cmd The system includes a second step (operation of the drive current control unit 20) which provides feedback control to the first step based on the current output value I0 output in the first step, and the second step controls the change amount ΔI of the current target value.cmd , and the target current value I cmd This includes the step of setting the control gain G based on the deviation e between the current output value I0 and the current output value I0 (operation of the gain setting unit 23).

[0043] According to the motor drive device 1 and motor drive method, appropriate feedback control is performed by appropriately changing the control gain, so the responsiveness of the drive current to transient control signals CMD can be significantly improved.

[0044] Furthermore, in the motor drive device 1, the gain setting unit 23 sets the change amount ΔI cmd Furthermore, the larger the deviation e, the higher the control gain G should be set, and the amount of change ΔI cmd Furthermore, the smaller the deviation e, the lower the control gain G is set. This allows the current target value I to be set. cmd During the rising or falling edge, feedback control prioritizing responsiveness is performed, and the current target value I cmd When the change is small (typically 0), feedback control prioritizing stability is performed. Therefore, the responsiveness of the drive current to transient control signals (CMD) is improved.

[0045] Furthermore, in the motor drive device 1, the gain setting unit 23 sets the change amount ΔI cmd However, it is determined which of the change ranges divided by multiple change thresholds X0, X1, ... belongs to, and it is also determined which of the deviation ranges divided by multiple deviation thresholds Y0, Y1, ... belongs to, and the change amount ΔI cmd The control gain G is set based on the combination of the change range to which the variable belongs and the deviation range to which the deviation e belongs. This reduces the processing load in the gain setting unit 23, allowing for faster current control and further improving the responsiveness of the drive current.

[0046] Furthermore, in the motor drive unit 1, the gain setting unit 23 selects a control gain G from among the gain setting values ​​G(X,Y) that are preset in correspondence with a combination of change range and deviation range. This further reduces the processing load on the gain setting unit 23, enabling faster current control and further improving the responsiveness of the drive current.

[0047] Furthermore, in the motor drive unit 1, the PID control unit 21 (feedback control unit) performs proportional control, which controls the manipulated variable in proportion to the deviation e; integral control, which controls the manipulated variable by accumulating the deviation e over time; and differential control, which controls the manipulated variable according to the change in the deviation e. This makes it possible to efficiently track the drive current in response to the control signal CMD.

[0048] Although the present invention has been specifically described above based on embodiments, the present invention is not limited to the above embodiments and can be modified without departing from its spirit.

[0049] For example, in the embodiment, a case where PID control is performed as an example of feedback control was described, but the present invention can also be applied to other feedback control methods such as PI control and PD control.

[0050] Furthermore, although the embodiment described a case in which the gain setting unit 233 sets the control gain by referring to the gain setting table, the gain determination unit 233 also considers the deviation e and the amount of change. cmd The control gain may be determined by calculation using a function with variable .

[0051] Furthermore, although the embodiment described the case in which the drive current output unit 10 has a switching circuit configuration, the drive current output unit 10 may have a circuit configuration other than a switching type, such as a linear type.

[0052] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this book is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]

[0053] 1. Motor drive unit 10 Drive current output section 20 Drive current control unit 21 PID Control Unit (Feedback Control Unit) 22 PWM control unit 23 Gain setting section 101 Motor 102 Controllers 231 Deviation Calculation Section 232 Change Amount Calculation Unit 233 Gain determination section

Claims

1. A motor drive device that controls and outputs drive current according to an external control signal, A drive current output unit that outputs the aforementioned drive current to the motor, A feedback control unit controls the operation of the drive current output unit based on the current target value indicated by the control signal and the current output value output from the drive current output unit, The system includes a gain setting unit that sets the control gain of the feedback control unit based on the amount of change in the current target value and the deviation between the current target value and the current output value. Motor drive device.

2. The gain setting unit sets the control gain higher as the amount of change and the deviation increase, and sets the control gain lower as the amount of change and the deviation decrease. The motor drive device according to claim 1.

3. The gain setting unit is, The change amount is determined to determine which of the change amount ranges, divided by multiple change amount thresholds, it belongs to. Determine which of the multiple deviation thresholds the aforementioned deviation belongs to. Based on the combination of the range of change to which the change amount belongs and the range of deviation to which the deviation belongs, the control gain is set. A motor drive device according to claim 1 or 2.

4. The gain setting unit selects the control gain from among the gain setting values ​​that are set in advance in correspondence with the combination of the change amount range and the deviation range. The motor drive device according to claim 3.

5. The feedback control unit performs proportional control, which controls the manipulated variable in proportion to the deviation; integral control, which controls the manipulated variable by accumulating the deviation over time; and differential control, which controls the manipulated variable in accordance with the change in the deviation. The motor drive device according to claim 1.

6. A motor drive method that controls and outputs the drive current according to an external control signal, The first step is to output the drive current to the motor, The system includes a second step that provides feedback control of the first step based on the current target value indicated by the control signal and the current output value output in the first step, The second step includes setting a control gain based on the amount of change in the current target value and the deviation between the current target value and the current output value. Motor drive method.

Images