Motor control device

Abstract

To provide a motor control device that can further improve the responsiveness of a motor. 【Solution means】The motor control device 10 outputs a torque command value τ based on a speed deviation ΔV that is the difference between a speed command value V ff2 and a speed detection value Vd, a speed control unit 16, and the speed command value V * A first feed-forward torque command value τ corresponding to the change amount of ff1 is calculated by a first feed-forward calculation unit 22, and the first feed-forward torque command value τ ff1 is the motor maximum torque τ max When it exceeds, the first feed-forward torque command value τ ff1 is the motor maximum torque τ max For a period longer than the period during which it exceeds, the motor maximum torque τ max A second feed-forward torque command value τ that is less than or equal to ff2 is output and added to the torque command value τ, and a current control unit 30 that controls the motor current based on the torque command value τ.

Description

[Technical Field]

[0001] This specification discloses a motor control device that controls a motor so that it drives at a target speed. [Background technology]

[0002] Motor control devices that drive a motor so that the detected speed of the motor matches the target speed have been widely known. Such motor control devices are used, for example, to control the motor that drives the spindle of a machine tool. In such motor control devices, a speed command value is generated from the target speed, a torque command value is calculated based on the speed deviation, which is the difference between this speed command value and the detected speed value, and a current corresponding to the torque command value is applied to the motor. Patent Document 1 discloses such a motor control device.

[0003] In general, in many control systems, not just the spindle control system, the motor is required to reach the target speed in the shortest possible time. Therefore, to achieve rapid acceleration and deceleration, the motor control device generates a step-function-like speed command value that changes up to the target speed. Consequently, if the detected motor speed differs significantly from the target speed, the motor control device will output a torque command value that exceeds the motor's maximum torque. However, this torque command value is limited by the motor's maximum torque. Then, a current corresponding to the motor's maximum torque is applied to the motor. This enables acceleration and deceleration that maximizes the motor's performance.

[0004] Incidentally, noise such as detection disturbances can be superimposed on the torque command value, negatively affecting control. Therefore, the torque command value is often filtered to remove high-frequency components. However, filtering makes it impossible to achieve sharp changes in the torque command value. As a result, there is a problem in that the maximum torque cannot be commanded immediately at the start of acceleration or deceleration.

[0005] Therefore, some propose calculating a feedforward torque command value based on the derivative of the speed command value and adding this feedforward torque command value to the filtered torque command value. This configuration can improve the motor's responsiveness to some extent. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-182381 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, if the speed command value changes abruptly in a step-like manner, the feedforward torque command value, which is proportional to its derivative, will have an impulse function shape that exceeds the motor's maximum torque. In this case, the feedforward torque command value is limited by the motor's maximum torque, and the feedforward torque command value is output only instantaneously. As a result, the feedforward torque command value becomes insufficient, and the motor's responsiveness deteriorates.

[0008] Therefore, this specification discloses a motor control device that can further improve the responsiveness of the motor. [Means for solving the problem]

[0009] The motor control device disclosed herein is characterized by comprising: a speed control unit that outputs a torque command value based on a speed deviation which is the difference between a speed command value and a speed detection value; a first feedforward calculation unit that calculates a first feedforward torque command value according to the amount of change in the speed command value; a second feedforward calculation unit that, when the first feedforward torque command value exceeds the maximum motor torque, outputs a second feedforward torque command value which is less than or equal to the maximum motor torque for a period longer than the period during which the first feedforward torque command value exceeds the maximum motor torque, and adds it to the torque command value; and a current control unit that controls the motor current based on the torque command value.

[0010] In this case, the second feedforward calculation unit may calculate the acceleration / deceleration time of the motor based on the motor's inertia, the controlled object's inertia, and the motor's maximum torque, and output the motor's maximum torque as the second feedforward torque command value during the acceleration / deceleration time.

[0011] In this case, the speed command value is in the shape of a step function, the first feedforward torque command value is in the shape of an impulse function, and the second feedforward calculation unit calculates the speed command value after it has changed in a step shape. r V0 is the initial speed command value, which is the speed command value before it changes in a step-like manner, and J is the motor inertia. m The motor shaft equivalent load inertia of the controlled object is J W If the maximum torque of the motor is τmax, the acceleration / deceleration time ta may be calculated based on Equation 1.

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[0012] Furthermore, the second feedforward calculation unit may output the maximum motor torque as the second feedforward torque command value after calculating the first feedforward torque command value which exceeds the maximum motor torque, until the speed deviation falls below a specified reference value.

[0013] Furthermore, the second feedforward calculation unit may calculate the second feedforward torque command value such that the time integral of the second feedforward torque command value is equal to the time integral of the first feedforward torque command value.

[0014] In this case, the second feedforward calculation unit may, for each control cycle, add the first feedforward torque command value to the current integral value to calculate an intermediate torque command value, output the smaller of the intermediate torque command value and the maximum motor torque as the second feedforward torque command value, and calculate a new integral value by adding the first feedforward torque command value and subtracting the second feedforward torque command value from the integral value.

[0015] Furthermore, the maximum torque of the motor is the torque limit value specified by the motor control device, or the actual maximum torque, and the actual maximum torque is the maximum output of the motor P max、 Set the motor base speed to V b Alternatively, when the motor speed is V, it may be defined by equations 2 and 3.

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[0016] According to the technology disclosed herein, even if the first feedforward torque command value is output only instantaneously, the second feedforward torque command value is output continuously, thereby maintaining high motor responsiveness. [Brief explanation of the drawing]

[0017] [Figure 1] Configuration block of the motor control device. [Figure 2] This figure shows the waveforms of each parameter when a step-shaped speed command value is input. [Figure 3] This is a block diagram showing the configuration of another example motor control device. [Figure 4] This flowchart shows the processing flow in another example of a motor control device. [Figure 5] This is a simplified flowchart of the flow shown in Figure 4. [Figure 6] This figure shows a concrete example of the process according to Figures 4 and 5. [Figure 7] Figures 4 and 5 show how the process is applied when the speed command value is a ramp function. [Figure 8] This figure shows the situation when the speed command value exceeds the base speed during the increasing process. [Figure 9] This is a block diagram showing the configuration of a motor control device in a comparative example. [Figure 10] This figure shows the acceleration speed and final torque command value in the motor control device of the comparative example. [Figure 11] This figure shows the speed and final torque command value during deceleration in the motor control device of the comparative example. [Figure 12] This is a block diagram showing the configuration of a motor control device in a comparative example. [Modes for carrying out the invention]

[0018] The configuration of the motor control device 10 will be described below with reference to the drawings. In the following description, "feedback" will be abbreviated as "FB" and "feedforward" as "FF". Figure 1 is a block diagram showing the configuration of the motor control device 10. This motor control device 10 controls the motor 32 that drives the target plant 34 (for example, the spindle of a machine tool). The command generation unit 12 of the motor control device 10 generates a speed command value V from a given target speed. * The subtractor 14 outputs this speed command value V. *Subtracts the speed detection value Vd therefrom and outputs the speed deviation ΔV. In order to obtain the speed detection value Vd, a speed sensor may be attached to the motor 32. Alternatively, a position sensor may be attached to the motor 32, and a value obtained by differentiating the detection value of the position sensor with a differentiator (not shown) may be output as the speed detection value Vd.

[0019] The speed control unit 16 calculates the FB torque command value τ fb ' based on the speed deviation ΔV. For example, the speed control unit 16 outputs a value obtained by multiplying the speed deviation ΔV by a prescribed proportional gain as the FB torque command value τ fb '.

[0020] The filter processing unit 18 performs filter processing on the FB torque command value τ fb ' to output the FB torque command value τ fb from which high-frequency components are removed. By providing such a filter processing unit 18, the adverse effects on control caused by the superposition of noises such as detected external disturbances are reduced.

[0021] The adder 26 adds the FB torque command value τ fb and the second FF torque command value τ ff2 described later. The output value of the adder 26 is subjected to limit processing by the limit processing unit 28. That is, there is an allowable maximum motor torque τ max for the motor 32. The limit processing unit 28 limits the output value from the adder 26 with this maximum motor torque τ max .

[0022] Here, the maximum motor torque τ max may be the actual maximum torque of the motor 32, or may be a value obtained by limiting the actual maximum torque with a torque limit value τ lim in the control device. The actual maximum motor torque τ max is a function of the motor speed V and is defined by the following equations 2 and 3.

Equation

[0023] Here, P max This is the maximum motor output, V b This is the motor base speed. The maximum motor output P max This value is defined as (base rotational speed) × (torque at base rotational speed). The maximum output P of this motor. max The motor's maximum speed and instantaneous maximum torque are both determined by the specifications of motor 32. Therefore, the motor's maximum output P max This can be considered the maximum output according to the motor specifications.

[0024] The limit processing unit 28 outputs a final torque command value τ. The current control unit 30 applies a current to the motor 32 corresponding to this final torque command value τ. This current control unit 30 includes, for example, an inverter. The motor 32 is driven by the application of current.

[0025] Here, there are two factors that prevent the realization of a steep torque command in the above-described configuration. These will be explained with reference to Figures 9 to 11. Figure 9 is a block diagram of a comparative example motor control device 10*. Figures 10 and 11 are diagrams showing the motor speed V and final torque command value τ during acceleration and deceleration in the motor control device 10*, respectively. In Figures 10 and 11, the dashed lines represent the ideal motor speed V and ideal final torque command value τ, and the solid lines represent the actual motor speed V and actual final torque command value τ obtained as a result of control by the motor control device 10*. The comparative example motor control device 10* has a different FF torque command value τ compared to the motor control device 10 in this example. ff1 , τ ff2 It differs in that it does not output.

[0026] One of the factors that prevents the realization of steep torque commands is the presence of the filter processing unit 18. While the filter processing unit 18 reduces the effects of disturbances, it also hinders the high-frequency response, causing the step-like torque command value τ to become blunted, as shown in Figure 10. This, in turn, slows down the change in motor speed V, worsening responsiveness. The second factor that prevents the realization of steep torque commands is due to the characteristics of the feedback. FF torque command value τ ff1 , τ ff2 In the case of the motor control device 10* of the comparative example that does not output, the speed detection value Vd is equal to the speed command value V * As the speed approaches the speed command value V, the torque command value due to the proportional gain decreases, and as shown in Figure 11, the step-shaped torque command value τ changes to a blunt shape. This also blunts the change in motor speed V, worsening responsiveness. Increasing the proportional gain can be considered to mitigate this problem, but in that case, the risk of adverse effects such as mechanical resonance and detection noise increases. Therefore, applying feedback using integral gain can be considered, but in this case, the speed detection value Vd becomes the speed command value V * There is a risk of overshooting. Therefore, it is difficult to set a high value for the integral gain.

[0027] Therefore, some have proposed adding a first FF calculation unit 22, as shown in Figure 12. In the case of the motor control device 10** of the comparative example shown in Figure 12, the first FF calculation unit 22 calculates the speed command value V * Based on the derivative value, the first FF torque command value τ ff1 Calculate the first FF torque command value τ. ff1 The speed command value V * This is the value obtained by multiplying the derivative of by a predetermined proportional gain. And the FB torque command value τ fb The first FF torque command value τ was calculated. ff1 The addition of this improves responsiveness.

[0028] However, in the configuration shown in Figure 12, the step-shaped speed command value V * It cannot handle the speed command value V. * If it is stepwise, its derivative, and consequently the first FF torque command value τ ff1 This takes the shape of an impulse function. And this first FF torque command value τ ff1 The motor's maximum torque τ maxIf it exceeds this value, the excess is limited by limit processing. In this case, the first FF torque command value τ ff1 Since the correction of the torque command value is instantaneous, it cannot prevent a deterioration in responsiveness.

[0029] Therefore, in this example, in addition to the first FF calculation unit 22, a second FF calculation unit 24 is also provided. This will be explained in detail below. As shown in Figure 1, the motor control device 10 has a differentiator 20, a first FF calculation unit 22, and a second FF calculation unit 24.

[0030] Differentiator 20 controls the velocity command value V * Differentiate the expression. The first FF calculation unit 22 calculates the speed command value V * Based on the derivative value, the first FF torque command value τ ff1 The first FF torque command value τ is calculated. ff1 For example, speed command value V * It is calculated by multiplying the derivative of by a predetermined proportional gain.

[0031] The second FF calculation unit 24 calculates the first FF torque command value τ ff1 Based on the second FF torque command value τ ff2 Calculate and output τ. ff1 ≤τ max In the case of τ ff2 =τ ff1 This is the result. On the other hand, the first FF torque command value τ ff1 The motor's maximum torque τ max If it exceeds τ, the second FF calculation unit 24 will ff1 >τ max For a period longer than the period in which this occurs, the motor's maximum torque τ max The following value is the second FF torque command value τ ff2 It outputs as follows. More specifically, in this case, the second FF torque command value τ ff2 The time integral of that value is the first FF torque command value τ ff1 This value is approximately the same as the time integral value of τ. ff2 The procedure for calculating this will be explained.

[0032] The second FF calculation unit 24 calculates the motor shaft equivalent load inertia J w Based on the second FF torque command value τ ff2 The output duration is calculated. Specifically, the motor's maximum torque τ max When outputting the speed command value V * The acceleration / deceleration time ta required to reach the target value is given by the second FF torque command value τ. ff2 This is calculated as the output duration. The acceleration / deceleration time ta is calculated using the following equation 1.

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[0033] Here, V r V0 is the speed command value after the stepwise change, and V0 is the speed command value before the stepwise change (hereinafter referred to as the "initial speed command value"). Also, J m It is a motor inertia, J w This is the motor shaft equivalent load inertia. The "motor maximum torque τ" mentioned in Equation 1 and the following explanation is used. max " may be the value calculated by equations 2 and 3, or the output values ​​of equations 2 and 3 may be the control torque limit value τ lim A value limited by that is also acceptable.

[0034] In any case, the second FF calculation unit 24 calculates the first FF torque command value τ ff1 The motor's maximum torque τ max If it exceeds this value, the acceleration / deceleration time ta is calculated based on Equation 1. Then, the second FF torque command value τ is set until the calculated acceleration / deceleration time ta has elapsed. ff2 As the maximum torque τ of the motor max It outputs the first FF torque command value τ. ff1 The motor's maximum torque τ max In the following cases, the second FF calculation unit 24 τ ff2 =τ ff1 Outputs.

[0035] Figure 2 shows the step-like speed command value V. *is a diagram showing the waveforms of each parameter when is input. As shown in the first row of FIG. 2, the speed command value V that changes in steps * is input. In this case, the first FF torque command value τ ff1 becomes an impulse function shape that exceeds the motor maximum torque τ max as shown in the second row of FIG. 2. The second FF calculation unit 24 calculates the acceleration / deceleration time ta when τ ff1 >τ max . Then, as shown in the third row of FIG. 2, the motor maximum torque τ max is output until the acceleration / deceleration time ta elapses.

[0036] On the other hand, the FB torque command value τ fb has a gentle rise and fall due to the influence of the filter processing unit 18 as shown in the fourth row of FIG. 2. This FB torque command value τ fb is added to the second FF torque command value τ ff2 and is limited by the limit processing unit 28. As a result, a pulse-wave-shaped final torque command value τ as shown in the fifth row of FIG. 2 is obtained. By applying a current to the motor 32 based on this final torque command value τ, the speed changes steeply as shown in the sixth row of FIG. 2, and the target speed can be reached in a short time.

[0037] As is clear from the above description, according to this example, even if the first FF torque command value τ ff1 is an impulse function, τ ff2 =τ max is continuously output. As a result, the torque lacking due to the filter processing is compensated by the second FF torque command value τ ff2 , so high responsiveness can be ensured. Note that when the first FF torque command value τ ff1 is not in the impulse function shape, the second FF calculation unit 24 may output τ ff1 =τ ff2 =τ ff1 regardless of the magnitude of the first FF torque command value τ ff1 . In this case, the second FF calculation unit 24 may sequentially calculate the differential value of the first FF torque command value τ ff1 and determine whether it is in the impulse function shape based on the change amount of this differential value.

[0038] Next, another example of the motor control device 10 will be described. Figure 3 is a diagram showing the configuration of the motor control device 10 in another example. In the example of Figure 3, the second FF calculation unit 24 also has τ ff1 >τ max In the case of τ ff1 >τ max For a longer duration than the duration of the maximum motor torque τ max The second FF torque command value τ is as follows: ff2 It outputs the second FF torque command value τ. ff2 The time integral of that value is the first FF torque command value τ ff1 It is approximately the same as the time integral value.

[0039] To explain in more detail, the second FF calculation unit 24 is τ ff1 >τ max If this is entered, the motor's maximum torque τ will be set until the speed deviation ΔV falls below the specified reference value Vdef. max The second FF torque command value τ ff2 The output is as follows. The reference value Vdef is not particularly limited, but is a value that can be considered practically zero, for example. As shown in Figure 3, the velocity deviation ΔV is input to the second FF calculation unit 24 in order to realize this control.

[0040] Even in this case, the first FF torque command value τ ff1 Even if it is an impulse function, continuously τ ff2 =τ max The output is as follows: As a result, the torque that is insufficient in the feedback control is the second FF torque command value τ ff2 This compensates for the lack of response, ensuring high responsiveness. In this example as well, the second FF calculation unit 24 calculates the first FF torque command value τ ff1 If it is not in the shape of an impulse function, the first FF torque command value τ ff1 Regardless of size τ ff2 =τ ff1 You may output this.

[0041] Next, another example of the motor control device 10 will be described. The block diagram of the motor control device 10 in this example is the same as in Figure 1 and will therefore be omitted. In this example, the second FF torque command value τ ff2 The time integral value is the first FF torque command value τ ff1 It is made to match the time integral value of τ. More specifically, the second FF calculation unit 24 calculates the integral value τ stk (Initial value is 0) First FF torque command value τ ff1 The values ​​are added sequentially, along with the second FF torque command value τ ff2 The following is subtracted sequentially. Also, the second FF calculation unit 24 performs τ stk >τ max In the case of τ ff2 =τ max and τ stk ≤τ max In the case of τ ff2 =τ stk The output will be generated sequentially.

[0042] Figure 4 shows the second FF torque command value τ in this example. ff2 This is a flowchart showing the calculation process for the integral value τ. stk The initial value is set to 0. As shown in Figure 4, the second FF calculation unit 24 calculates the first FF torque command value τ ff1 The motor's maximum torque τ max Check whether it exceeds (S10). ff1 >τ max In this case, the second FF calculation unit 24 calculates the motor's maximum torque τ max The second FF torque command value τ ff2 Output as (S12). This second FF torque command value τ ff2 This is the FB torque command value τ fb It is added to. Also, the second FF calculation unit 24 calculates the integral value τ stk The first FF torque command value τ ff1 In addition, the second FF torque command value τ is added. ff2 Subtracting this, the integral value τ stk After updating it, return to the first step (S12).

[0043] Meanwhile, τ ff1 ≤τ maxIn the following cases, the second FF calculation unit 24 calculates the first FF torque command value τ ff1 and the integral value τ stk The sum of these is the motor's maximum torque τ max Check whether it exceeds (S18).

[0044] Motor maximum torque τ max If it exceeds τ, the second FF calculation unit 24 will ff2 =τ max The output is (S20). The second FF calculation unit 24 outputs the current integral value τ. stk The first FF torque command value τ ff1 Add this to the second FF torque command value τ ff2 The value is updated by subtracting the value, and then the process returns to the first step (S20).

[0045] On the other hand, in step S18, the first FF torque command value τ ff1 and the integral value τ stk The sum of these is the motor's maximum torque τ max If it does not exceed the first FF torque command value τ, the second FF calculation unit 24 calculates the first FF torque command value τ ff1 The current integral value τ stk The value obtained by adding this is the second FF torque command value τ ff2 The output is as follows (S22). The second FF calculation unit 24 then outputs a new integral value τ. stk Set the value to 0 and return to the first step (S22).

[0046] Figure 5 is a simplified flowchart of the flow shown in Figure 4. In Figure 5, the integral value τ stk Initial value and intermediate torque command value τ tmp The initial values ​​of are all 0. The second FF calculation unit 24 calculates the current integral value τ at each control period tc. stk The first FF torque command value τ ff1 The intermediate torque command value τ is obtained by adding this value. tmp The calculation is performed as follows (S30). Then, the second FF calculation unit 24 calculates the intermediate torque command value τ tmp and motor maximum torque τ max Of these, the smaller value is the second FF torque command value τ ff2It outputs as (S32). The second FF calculation unit 24 also outputs the current integral value τ stk The first FF torque command value τ ff1 In addition, the second FF torque command value τ is added. ff2 The value obtained by subtracting this is the new integral value τ stk This is calculated as follows (S32). The same process is repeated sequentially thereafter.

[0047] A specific example of the process according to Figures 4 and 5 will be explained with reference to Figure 6. Figure 6 shows the first FF torque command value τ. ff1 , second FF torque command value τ ff2 , and the integral value τ stk This graph shows an example. In the example in Figure 6, the first FF torque command value τ ff1 is 4.5 × τ max This is the shape of the impulse function. In this case, naturally, τ ff1 >τ max Therefore, the second FF calculation unit 24, τ ff2 =τ max Outputting τ stk =τ ff1 -τ max = 3.5 × τ max Let's assume that.

[0048] In the next control period tc, τ stk >τ max , τ ff1 Since = 0, the second FF calculation unit 24 is τ ff2 =τ max Outputting τ stk =τ stk -τ max = 2.5 × τ max Let's do this. If we repeat this process two more times, τ stk = 0.5 × τ max In this case, the second FF calculation unit 24 is τ ff2 =τ stk = 0.5 × τ max Outputting τ stk Let = 0.

[0049] As is clear from the above explanation, in this example, the second FF torque command value τ ff2The time integral is the first FF torque command value τ ff1 This is equivalent to the time integral of τ. And as a result, the first FF torque command value τ ff1 Even if it is output only momentarily, the second FF torque command value τ ff2 This is continuously output. As a result, the responsiveness of the motor 32 can be maintained at a high level.

[0050] Note that the configuration in this example is based on the first FF torque command value τ ff1 This is effective not only when the waveform is in the shape of an impulse function, but also when it is in the shape of other waveforms. For example, as shown in Figure 7, the speed command value V * Let's consider the case where the curve has a ramp function shape. In this case, the first FF torque command value τ ff1 This takes the shape of a step function. At this point, the previous integral value τ stk And the first FF torque command value τ ff1 The sum of these values ​​is the motor's maximum torque τ max If it exceeds τ ff2 =τ max The output is as follows: Also, the integral value τ stk The output τ ff2 This amount is subtracted. By repeating this process, the first FF torque command value τ ff1 Even after time t1 when it becomes 0, the second FF torque command value τ ff2 The output is then the second FF torque command value τ. ff2 The time integral is the first FF torque command value τ ff1 This allows the time integral to be matched. This makes it possible to appropriately set the speed of motor 32 to the speed command value V * It can be made to follow.

[0051] Furthermore, as shown in Figure 8, the speed command value V * During the increasing process, the base velocity V b Let's consider the case where it exceeds [a certain value]. As is clear from Equations 2 and 3, the maximum motor torque τ max This is the speed command value V of motor 32. * base velocity V b It decreases when it exceeds a certain value. Therefore, in the example in Figure 8, the maximum motor torque τ maxThe first FF torque command value τ changes as shown by the dashed line. ff1 Of these, the motor's maximum torque τ max The excess amount from there is the second FF torque command value τ ff2 It is output as follows. In other words, according to this example, the first FF torque command value τ ff1 Of these, the motor's maximum torque τ max The excess portion from is the integral value τ stk It can be held as such. As a result, the second FF torque command value τ ff2 The time integral is the first FF torque command value τ ff1 This allows the time integral to be matched. This enables the speed of motor 32 to be appropriately controlled to the speed command value V. * It can be made to follow.

[0052] It should be noted that the configurations described so far are all examples, and other configurations may be modified as appropriate as long as the configuration of claim 1 is obtained. For example, in the description so far, τ ff1 >τ max In the case of τ ff2 =τ max The example given is the second FF torque command value τ ff2 The maximum motor torque τ max It may be less than the second FF torque command value τ. ff2 Motor maximum torque τ max If it is made smaller, the second FF torque command value τ will be used for a longer period of time. ff2 You just need to keep outputting it. Also, in Figures 1 and 3, the area enclosed by the dashed rectangle may be a computer having a processor and memory. [Explanation of Symbols]

[0053] 10,10*,10** Motor control device, 12 Command generation unit, 14 Subtractor, 16 Speed ​​control unit, 18 Filter processing unit, 20 Differentiator, 22 First FF calculation unit, 24 Second FF calculation unit, 26 Adder, 28 Limit processing unit, 30 Current control unit, 32 Motor, 34 Target plant.

Claims

1. A speed control unit that outputs a torque command value based on the speed deviation, which is the difference between the speed command value and the speed detection value, A first feedforward calculation unit that calculates a first feedforward torque command value corresponding to the amount of change in the speed command value, A second feedforward calculation unit outputs a second feedforward torque command value that is less than or equal to the maximum motor torque for a period longer than the period during which the first feedforward torque command value exceeds the maximum motor torque, and adds it to the torque command value, when the first feedforward torque command value exceeds the maximum motor torque. A current control unit that controls the motor current based on the torque command value, A motor control device characterized by comprising:

2. A motor control device according to claim 1, The second feedforward calculation unit calculates the acceleration / deceleration time of the motor based on the motor's inertia, the controlled object's inertia, and the motor's maximum torque, and outputs the motor's maximum torque as the second feedforward torque command value during the acceleration / deceleration time. A motor control device characterized by the following features.

3. A motor control device according to claim 2, The speed command value has a step function shape, and the first feedforward torque command value has an impulse function shape. The second feedforward calculation unit calculates the speed command value after it has been changed in a step-like manner, V ｒ The initial speed command value, which is the speed command value before it changes in a step-like manner, is V ０ Motor inertia J ｍ The motor shaft equivalent load inertia of the controlled object is J Ｗ A motor control device characterized in that, when the maximum torque of the motor is τmax, the acceleration / deceleration time ta is calculated based on Equation 1. [Math 1]

4. A motor control device according to claim 1, The motor control device is characterized in that the second feedforward calculation unit outputs the maximum motor torque as the second feedforward torque command value after the first feedforward torque command value, which exceeds the maximum motor torque, is calculated, until the speed deviation falls below a specified reference value.

5. A motor control device according to claim 1, The motor control device is characterized in that the second feedforward calculation unit calculates a second feedforward torque command value such that the time integral of the second feedforward torque command value is equal to the time integral of the first feedforward torque command value.

6. A motor control device according to claim 5, The second feedforward calculation unit performs the following for each control cycle: The current integral value is added to the first feedforward torque command value to calculate the intermediate torque command value. The smaller of the intermediate torque command value and the maximum motor torque is output as the second feedforward torque command value. The integral value is calculated by adding the first feedforward torque command value and subtracting the second feedforward torque command value from the aforementioned integral value, and this result is obtained as a new integral value. A motor control device characterized by the following features.

7. A motor control device according to any one of claims 1 to 6, The aforementioned maximum motor torque is either the torque limit value specified by the motor control device or the actual maximum torque. The actual maximum torque mentioned above is calculated by setting the motor's maximum output to P ｍａｘ、 Set the motor base speed to V ｂ When the motor speed is V, the following is defined by equations 2 and 3: A motor control device characterized by the following features. [Math 2]

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