WO2020235130A1

WO2020235130A1 - Motor drive device and method for controlling motor drive device

Info

Publication number: WO2020235130A1
Application number: PCT/JP2020/001403
Authority: WO
Inventors: 隆一小川; 野村　昌克; 山本　康弘; 淳也矢野
Original assignee: 株式会社明電舎
Priority date: 2019-05-23
Filing date: 2020-01-17
Publication date: 2020-11-26
Also published as: CN113875145A; JP2020191744A; JP6750707B1; CN113875145B

Abstract

On the basis of a detected motor angular velocity ω_M and a velocity command ω^*, a velocity control unit 1 outputs a torque command T^*. A vibration suppression control unit 2 subtracts the detected motor angular velocity ω_M from an estimated motor angular velocity ω_est to extract the vibration component, feeds back a compensation torque T_FB through a filter 22 which does not compensate low-frequency components and high-frequency components of the vibration component, and adds the compensation torque T_FB to the torque command T^* to calculate a vibration suppressing torque command T^**. A current control unit 3 outputs a gate signal on the basis of the detected motor phase, the detected current, and the aforementioned vibration suppressing torque command. An inverter 4 controls a switching element on the basis of the gate signal, and outputs a voltage to the motor M. In the motor drive device, it is possible to converge to a torque command inputted from higher-level control in a normal state, a lower-order model can be easily implemented, and stability of current control is increased.

Description

Motor drive device and control method of motor drive device

The present invention relates to a system in which a motor drives a multi-inertial system of two or more inertial systems, and particularly relates to vibration suppression.

A mechanism that generates a DC voltage consisting of a combination of a battery or an AC power supply and a rectifier (AC-DC converter), an inverter that converts the DC voltage into an AC voltage and applies it to a motor (electric motor), and the applied electrical energy. Consider a two-inertial drive system consisting of a motor that rotates by converting it into mechanical energy, a single load connected to the motor by a shaft, or the like, or a multi-inertial drive system in which a plurality of loads are connected.

Here, the inverter generates an AC voltage with an amplitude and frequency that allows the motor to operate with an appropriate torque based on a torque command generated by operating the accelerator or operation panel, and applies it to the motor. Systems with such a drive system include, for example, elevators and machine tools.

In such a drive system via a shaft, when a load is driven, a reaction force against torsion may be generated in the shaft, which may excite resonance. In addition, the inertial system may vibrate due to the disturbance component applied to the load. There is known a method of taking countermeasures against the vibration of this inertial system by improving the control.

For example, in the vibration suppression control for automobiles shown in Patent Document 1, the target response by the total inertia converted to the motor shaft is compared with the detected motor angular velocity, and the vibration component is fed back to suppress the vibration.

In the vibration suppression control for a test device such as a transmission in Patent Document 2, vibration suppression that does not depend on the motor rotation speed is performed by detecting and feeding back the output torque.

In the vibration suppression control for machine tools of Patent Document 3, vibration suppression is performed by comparing the speeds of the motor and the driven portion and feeding back the vibration component.

In the vibration suppression control of the multi-inertial system of Patent Document 4, simple vibration suppression control is achieved by achieving both disturbance observer and resonance ratio control.

In the vibration suppression control of Patent Document 1, the application target is limited to automobiles, and the influence of the vibration suppression control on the current control system when a high frequency disturbance is input to the inertial system is not considered.

The vibration suppression control of Patent Document 2 requires an output torque detecting means. Many electric motor drive systems do not have output torque detection means, and there is a risk of design changes and parts procurement costs when applied to general electric motor drive systems.

In the vibration suppression control of Patent Document 3, a speed detector is required for both the motor and the driven unit. When there are two detectors, problems such as increased component cost and increased failure risk occur as compared with the case of one detector.

In the vibration suppression control of Patent Document 4, since the low frequency component is fed back, the torque command after the vibration suppression compensation does not converge to the torque command from the speed control in the steady state. It is not suitable when you want to control the motor torque to a specific value regardless of the magnitude of the command value and the presence or absence of disturbance.

From the above, it is an issue that the motor drive device can converge to the torque command input from the upper control in the steady state, the low-order model can be easily mounted, and the stability of the current control is improved. Become.

Patent No. 6243279 Patent No. 5037024 Patent No. 6412071 Patent No. 5329203

The present invention has been devised in view of the above-mentioned conventional problems, and one aspect thereof is a motor driving device for driving one or a plurality of loads by a motor connected to an inverter. A speed control unit that outputs a torque command based on the motor angular speed and speed command, and a filter that extracts the vibration component by subtracting the detected motor angular speed from the estimated motor angular speed and does not compensate the low frequency component and high frequency component for the vibration component. Based on the vibration suppression control unit that feeds back the compensation torque and adds the compensation torque to the torque command to calculate the vibration suppression torque command, the detection motor phase, the detection current, and the vibration suppression torque command. It is characterized by including a current control unit that outputs a gate signal and an inverter that controls a switching element based on the gate signal and outputs a voltage to the motor.

Further, as one aspect thereof, the vibration suppression control unit calculates the estimated motor angular velocity by multiplying the vibration suppression torque command by the inertial frame model, and obtains the detected motor angular velocity from the estimated motor angular velocity. A subtraction unit for subtraction, a filter that inputs the output of the subtraction unit and outputs the compensation torque, and an addition unit that adds the compensation torque to the torque command and outputs it as the vibration suppression torque command are provided. It is characterized by that.

Further, as one aspect thereof, the transmission coefficient of the filter is characterized by the following equation (9).

G _FB : Transfer function Jr: Internal model inertia ζ _H : Strength of suppression compensation ω _H : Frequency band s: Laplace operator.

According to the present invention, in a motor drive device, it is possible to converge on a torque command input from a higher-level control in a steady state, a low-order model can be easily mounted, and the stability of current control can be improved.

Connection configuration diagram of motor and load. The control system block diagram of the motor drive device in embodiment. Inertial frame block diagram in the embodiment. The block diagram of the vibration suppression control part in an embodiment. The step response diagram in the embodiment. Bode plot in the embodiment.

Hereinafter, embodiments of the motor drive device according to the present invention will be described in detail with reference to FIGS. 1 to 6.

[Embodiment]
FIG. 1 shows a connection configuration diagram of a motor and a load in this embodiment. FIG. 1 shows a four inertial drive system in which a motor M drives three loads A, B, and C via a shaft. The reason for using the 4-inertial drive system is to explain as an example of multi-inertial system control, and the embodiment is not limited to the 4-inertial system. That is, the number of loads is not limited to three, and any number of one or more may be used. Motor torque T _M is the torque which is generated by controlling the current flowing through the motor M by the inverter to drive the motor M and the load A by the motor torque T _M, B, and C. Hereinafter, the drive system of FIG. 1 is referred to as a plant.

FIG. 2 shows a control system configuration diagram according to the present embodiment. The speed command ω ^* is input to the control system according to the amount of operation of the accelerator and operation panel. The position control may be performed before the speed command ω ^* , and the speed command ω ^* may be generated there. The speed control unit 1 outputs a torque command T ^* for following the speed command ω ^* based on the input speed command ω ^* and the detection motor angular velocity ω _M.

The vibration suppression control unit 2 is a control unit that is the target of the present embodiment, and is a torque command for suppressing vibration from the input torque command T ^* and the detection motor angular velocity ω _M (hereinafter referred to as vibration suppression torque command). Output T ^** .

The vibration suppression torque command T ^** , the detection motor phase, and the detection current are input to the current control unit 3, the current control calculation for realizing the vibration suppression torque command T ^** is performed, and the gate signal is given to the inverter 4.

In the inverter 4, switching is performed according to the gate signal, and a voltage is applied to the motor M. When the voltage to the motor M is applied current flows, speed, motor torque T _M corresponding to the current is generated.

Here, although the detection motor angular velocity ω _M and the detection motor phase are used in FIG. 2, the estimated motor phase may be calculated by current control or the like, that is, the speed sensor may be omitted. In that case, the estimated motor angular velocity is input to the speed control unit 1 and the vibration suppression control unit 2 instead of the detected motor angular velocity ω _M. In the present specification, the detected motor angular velocity ω _M shall include the estimated motor angular velocity, and the detected motor phase shall include the estimated motor phase.

In addition, regarding the following examination of vibration suppression control, it is assumed that the current control is sufficiently accurate, and it is regarded as the first-order lag transfer function of the same time constant as the current control response.

FIG. 3 is a representation of FIG. 1 in the form of a block diagram. _{_{_{J M, J A, J B}}} , J C respectively motor M, the load A, load B, and the inertia of the load C. _{_{Further, D MA, D AB, D}} BC motor M and the load A, the load A and the load B, the attenuation constant representing the loss of the shaft to be connected to the load B load C, K _MA, K _AB, the K _BC motor The rigidity of the shaft connecting M and the load A, the load A and the load B, and the load B and the load C. The loss of the shaft refers to a component such as friction generated according to the angular velocity at which the shaft twists.

Block

7,11,15,18 with inertia, such as 1 / J _M s denotes the transfer function of the angular speed from the torque.

Blocks

9, 13 and 17 using shaft coefficients such as D _MA s + K _MA / s show the transfer function from angular velocity to torque.

Subtractors

8, 12 and 16 by feedback before

blocks

9, 13 and 17 using the transfer function of the shaft coefficient are for deriving the angular velocity at which the shaft twists from the difference between the two angular velocities. The

subtractors

6, 10 and 14 by feedback before the

blocks

7, 11, 15 and 18 using the transfer function of the inertia of the motor M or the loads A, B and C express the reaction force from the shaft.

A specific description will be given with reference to FIG. In the subtraction unit 5 subtracts the disturbance torque T _dis from the motor torque T _M. In the subtraction unit 6, the output of the first shaft block 9 is subtracted from the output of the subtraction unit 5.

In the motor inertia block 7, the detected motor angular velocity ω _M is calculated by multiplying the output of the subtraction unit 6 by the motor inertia transfer function 1 / J _M s. The subtracting unit 8 subtracts the output of the first load inertia block 11 from the detection motor angular velocity ω _M. In the first shaft block 9, the output of the subtraction unit 8 is multiplied by the first shaft transfer function D _MA s + K _MA / s.

The subtraction unit 10 subtracts the output of the second shaft block 13 from the output of the first shaft block 9. In the first load inertia block 11, it is multiplied by a first load transfer function 1 / J _A s the output of the subtraction unit 10. The subtracting unit 12 subtracts the output of the second load inertia block 15 from the output of the first load inertia block 11.

In the second shaft block 13, the output of the subtraction unit 12 is multiplied by the second shaft transfer function D _AB s + K _AB / s. The subtraction unit 14 subtracts the output of the third shaft block 17 from the output of the second shaft block 13. In the second load inertia block 15, the output of the subtraction unit 14 is multiplied by the second load transfer function 1 / J _B s. The subtraction unit 16 subtracts the output of the third load inertia block 18 from the output of the second load inertia block 15.

In the third shaft block 17, the output of the subtraction unit 16 is multiplied by the third shaft transfer function _DC C s + K _BC / s. In the third load inertia block 18, the output of the third shaft block 17 is multiplied by the third load transfer function 1 / J _C s.

Although FIG. 3 shows a case where the load is three, the load may be one or more. When there is one load, the plant transfer function _GP is a block from the subtraction unit 6 to the first load inertia block 11 (however, there is no subtraction unit 10). When there are two loads, the blocks are from the subtraction unit 6 to the second load inertia block 15 (however, there is no subtraction unit 14). When the load is 4 or more, the necessary blocks may be added to FIG.

Motor torque T _M and, by entering the disturbance torque T _dis, the motor M on the basis of FIG. 3, the load A, B, C are driven. The motor angular velocity is detected and used as the detected motor angular velocity ω _{M in} the control system of FIG. Motor torque T _M, the subsequent subtraction of the disturbance torque T _dis, referred to as the plant transfer function G _P from the plant input torque to the detection motor angular velocity omega _M. However, the plant does not have to be a combination of linear transfer functions as shown in FIG. 3, that is, a configuration that can be combined into one plant transfer function _GP , and is a plant having non-linear elements such as gear backlash. Also, this embodiment is applicable.

FIG. 4 shows a configuration diagram of the vibration suppression control unit 2. _GP is the plant transfer function shown in FIG. The plant transfer function _GP is an external term of the vibration suppression control unit 2 in FIG. 2, but is described for the sake of clarity of the vibration suppression control as a whole.

In this embodiment, a detection means is provided for the resonating model, and the result is compared with the in-control calculation result having a component other than the resonance and fed back to the output. This is the basic idea of control. A model that expresses components other than resonance is a model that roughly represents the entire inertial system, and this is a first-order lag with the sum of all inertias of the inertial system as the time constant.

A torque command T ^* is input to the vibration suppression control unit 2. The adder 19 adds the torque command T ^* and the fed-back compensation torque T _FB to calculate the vibration suppression torque command T ^** .

The inertial frame model block 20 calculates the estimated motor angular velocity ω _est by multiplying the vibration suppression torque command T ^** by the inertial frame model (1 / _Jrs ) inside the control. Here, J _r is an internal model inertia. The vibration suppression torque command T ^** is the motor torque T _M via the (omitted regarded as small primary delay time constant in this case) the current control system. In the subtracter 5, the disturbance torque T _dis is subtracted from the motor torque T _M, is input to the plant transfer function G _P. The output of the plant transfer function _GP is the detection motor angular velocity ω _M.

In the subtraction unit 21, the detected motor angular velocity ω _M is subtracted from the estimated motor angular velocity ω _est . In other words, the internal model is compared with the detected value from the plant. The subtracted result is added to the torque command T ^* as a compensating torque T _FB for suppressing vibration via the filter 22 (transfer function G _FB ).

Here, assuming that the speed control and current control in FIG. 2 operate without any special problem, only the vibration suppression control is considered.

The basic concept of vibration suppression control (FIG. 4) of the present embodiment will be described. The motor angular velocity ω _M detected from the plant vibrates due to the rigidity of the plant. On the other hand, the internal model is expressed only by the integral considering the inertia, and the estimated motor angular velocity ω _est obtained from it has no vibration component. In other words, if the internal model is appropriate, only the vibration component of the detected motor angular velocity ω _M can be extracted by comparing the detected motor angular velocity ω _M with the estimated motor angular velocity ω _est . Then, the obtained vibration component is passed through an appropriate filter (transfer function G _FB ) and fed back to the torque command T ^* , so that the vibration of the detected motor angular velocity ω _M can be suppressed. The above is the basic concept of vibration suppression.

The vibration suppression control according to the configuration of FIG. 4 will be described using a mathematical formula. Here, it is assumed that the current control system can be regarded as a first-order lag with a small time constant, and the vibration suppression torque command T ^** and the motor torque _TM are equal. In addition, the motor angular velocity of the plant is considered to be detected accurately without delay.

First, the inertial frame model inside the control will be described. Since we want to extract the vibration component by comparing the detected motor angular velocity ω _M with the estimated motor angular velocity ω _est as described above, the estimated motor angular velocity ω _est may be a simulation of the rough movement of the motor angular velocity.

Therefore, in order to simulate that the loads A, B, and C are connected to the motor M, the internal model inertia J _r is adjusted to a value equal to or higher than the inertia J _M so that vibration can be easily suppressed. As a desirable value when the inertia information is known in advance, the internal model inertia Jr is the sum of the inertias of the motor M and the total loads A, B, and C as shown in the following equation (1).

As a caveat here, when transmitting force via gears, etc., when converting rotational force such as wheels into forward and backward movement, the inertia of each load A, B, C seen from the motor M is the inertia measured separately. Since the above looks different, the estimated motor angular velocity ω _est deviates from the detected motor angular velocity ω _M if the equation (1) remains as it is. In such a case, the inertia of each load may be converted into the motor shaft using the gear ratio and turning radius, and the sum may be taken.

Next, the design of the filter (transfer function G _FB ) will be described. The transfer function from the torque command T ^* and the disturbance torque T _dis to the motor torque T _M is the following equation (2). The transfer function from the torque command T ^* and the disturbance torque T _dis to the detected motor angular velocity ω _M is as shown in equation (3) below.

Here, expressing the plant transfer function G _P molecules G _PN, in the denominator G _PD. Further, in consideration of suppressing the vibration of the detection motor angular velocity ω _M , the coefficient portion of the torque command T ^{* in} the equation (3) is set to G _X. Then, the following equations (4) and (5) are obtained.

_Paying attention to the _designable transfer functions 1 / _Jrs , G _FB , replace with the following equation (6), and rearrange the equation (5) to obtain the following equation (7).

(7) Focusing on the expression of the denominator, it can be seen that has a resonance caused by the denominator G _PD of the plant transfer function G _P in a form that can be suppressed by G _H.

Here, in the vibration suppression of the present embodiment, the following two points are emphasized, and the design is such that the low frequency component and the high frequency component are not compensated.
-If there is no vibration, the value of the torque command T ^* is not changed, that is, steady compensation is not performed.
-No compensation is provided that requires consideration of the balance with the current control response.

From _Eqs. (3) and (6), based on the fact that the response of the detected motor angular velocity ω _M to the disturbance torque T _dis is G _X G _H , set G _H to the notch filter as shown in Eq. (8). .. ω _H determines the frequency band, and ζ _H determines the strength of suppression compensation.

The frequency band ω _H and the strength of suppression compensation ζ _H are adjusted so that vibration can be suppressed according to the plant, but in general, the frequency band ω _H is from the antiresonance point of the plant transfer function _GP. Set low, and if the suppression compensation strength ζ _H is small, the vibration suppression performance is weak, and if it is large, a steep compensation torque T _FB is generated, so it is better to set it to about 0.2 <ζ _H <0.8.

For the filter (transfer function G _FB ) used for vibration suppression control, the following equation (9) is derived from equation (8).

The above is the description of the vibration suppression control of this embodiment. The effect of this embodiment was confirmed by simulation. FIG. 5 shows the simulation results for the step response. The left side of FIG. 5 shows the case where the torque command T ^* is changed, and the right side shows the case where the disturbance torque T _dis is changed. It can be seen that the vibration of the detected motor angular velocity ω _M is suppressed regardless of whether the torque command T ^* or the disturbance torque T _dis is changed. Both results even torque command T ^* and the vibration suppression torque command T ^**, where that is the motor torque T _M is seen to converge eventually equal.

Therefore, it can be seen that the vibration of the multi-inertial system can be suppressed while achieving the purpose of suppressing the vibration of the present embodiment, "the value of the torque command T ^* is not changed when there is no vibration". The deviation in the degree of increase in the angular velocity in the disturbance torque response is derived from the fact that the torque that cancels the disturbance is generated by the amount of vibration suppression only when there is control.

FIG. 6 shows a Bode diagram. Since it is a 4-inertial system, there are three resonance points without vibration suppression control. When vibration suppression is performed, the gain at the resonance point can be suppressed for both the response to the torque command T ^* and the response to the disturbance torque T _dis .

Consider the features of this embodiment.

The first feature is steady-state characteristics. In the steady state after vibration suppression, the vibration suppression torque command T ^** becomes equal to the torque command T ^* . This is advantageous when it is desired to output a particular motor torque T _M or without disturbance.

The second feature is the order of the internal model. Normally, when trying to reproduce the resonance of a multi-inertial system with an internal model, the order of the transfer function becomes high, and the coefficient also differs greatly depending on the term, so it is necessary to pay attention to the decimal point position and calculation error at the time of mounting. However, internal model 1 / J _r s of the present embodiment is able to reduce the difficulties of the orders lower mounting.

The third feature is the consideration of high frequency disturbance. If the vibration suppression control is designed to compensate for high-frequency disturbance, the compensation torque fluctuates at high frequencies, and there is a risk of destabilizing the current control. On the other hand, in the present embodiment, the _GH that contributes to the disturbance response is set as in the equation (8), and the stability is ensured by not performing compensation for high frequencies.
The above are the features of this embodiment.

The effects of this embodiment will be described below.

After subtracting the estimated motor angular velocity ω _est , which has no vibration component, from the vibrating detection motor angular velocity ω _{M, the} torque command input from the upper control in the steady state is fed back through a filter that does not compensate for low and high frequencies. Can converge to T ^*
It can be easily implemented with a low-order model, and it is possible to perform vibration suppression control of a multi-inertial system that does not make current control unstable.

Conventionally, vibration control of automobiles may be performed by expressing resonance due to shaft rigidity with a model. This can be controlled with feedforward without overshoot, but model accuracy is important instead.

The expression term of resonance (rigidity) when the vehicle model is made into a discrete transfer function is considerably smaller than the other terms, but if it is regarded as 0 and approximated, all the representations of resonance disappear, and vibration suppression Can not be done. Therefore, in the past, measures have been taken specifically for damping control to express resonance.

The control of this embodiment does not express resonance, but makes it possible to perform vibration damping control with a simple transfer function expression.

For Patent Documents 1 to 4, the influence on the current control system when a high-frequency disturbance is input to the inertial system is taken into consideration, no output torque detecting means is required, and the speed detector is at most a motor. On the other hand, there is an advantage that only one is required, and the torque command after vibration suppression in the steady state converges to the torque command from the speed control.

Although the above description has been made in detail only with respect to the specific examples described in the present invention, it is clear to those skilled in the art that various modifications and modifications can be made within the scope of the technical idea of the present invention. It goes without saying that such modifications and modifications fall within the scope of claims.

Claims

A motor drive that drives one or more loads by a motor connected to an inverter.
A speed control unit that outputs a torque command based on the detection motor angular velocity and speed command,
The detected motor angular velocity is subtracted from the estimated motor angular velocity to extract the vibration component, the vibration component is passed through a filter that does not compensate for the low frequency component and the high frequency component, the compensation torque is fed back, and the compensation torque is added to the torque command. Vibration suppression control unit that calculates the vibration suppression torque command
A current control unit that outputs a gate signal based on the detection motor phase, the detection current, and the vibration suppression torque command.
An inverter that controls a switching element based on the gate signal and outputs a voltage to the motor.
A motor drive device characterized by being equipped with.
The vibration suppression control unit
An inertial model block that calculates the estimated motor angular velocity by multiplying the vibration suppression torque command by an inertial model.
A subtraction unit that subtracts the detected motor angular velocity from the estimated motor angular velocity,
The filter that inputs the output of the subtraction unit and outputs the compensation torque,
The motor drive device according to claim 1, further comprising an adder that adds the compensation torque to the torque command and outputs the vibration suppression torque command.
The motor drive device according to claim 2, wherein the transmission coefficient of the filter is the following equation (9).

G FB : Transfer function Jr: Internal model inertia ζ H : Strength of suppression compensation ω H : Frequency band s: Laplace operator
A control method for a motor drive device that drives one or more loads by a motor connected to an inverter.
The speed control unit outputs a torque command based on the detected motor angular velocity and speed command.
In the vibration suppression control unit, the detection motor angular velocity is subtracted from the estimated motor angular velocity to extract the vibration component, the compensation torque is fed back through the filter that does not compensate the low frequency component and the high frequency component, and the compensation torque is used as the torque. Calculate the vibration suppression torque command by adding to the command,
The current control unit outputs a gate signal based on the detection motor phase, the detection current, and the vibration suppression torque command.
A method for controlling a motor drive device, which comprises controlling a switching element based on the gate signal in an inverter and outputting a voltage to the motor.