JP6183554B2 - Periodic disturbance automatic suppression device - Google Patents

Description

  The present invention relates to an automatic periodic disturbance suppressing device, and more particularly to an automatic periodic disturbance suppressing device that suppresses torque ripple while performing current error correction.

  Periodic disturbance generation suppression control includes power system control in power receiving / transforming equipment, robot positioning control, dynamometer system axial torque resonance suppression, motor housing vibration suppression (related to riding comfort of electric vehicles, elevators, etc.) Etc.), and it is desired to suppress the periodic disturbance in each of these products with high accuracy.

  For example, a motor generates torque ripple in principle, causing various problems such as vibration, noise, adverse effects on riding comfort, and electrical / mechanical resonance. In particular, in an embedded magnet type PM motor, cogging torque ripple and reluctance torque ripple are generated in a composite manner. As a countermeasure, a periodic disturbance observer compensation method has been proposed as a control method for suppressing torque ripple.

FIG. 5 is a control block diagram relating to the n-th order torque ripple frequency component of the periodic disturbance observer known from Patent Document 1 and Non-Patent Document.
Reference numeral 1 denotes a torque ripple compensation value calculation unit. The difference between the control command r _n (usually 0) of the sine wave / cosine wave and the estimated values dT _A ^ _n and dT _B ^ _n by the periodic disturbance observer 3 is respectively calculated as the sine wave / cosine. By multiplying the wave values and adding them, a torque ripple compensation command T _C ^* _n is generated and output to the controlled object 2. In the control object 2, there is a periodic disturbance (hereinafter referred to cycle disturbance dT _n) is generated. For example, if the object to be controlled is a motor, a torque ripple that is a disturbance synchronized with the rotational speed due to cogging torque or the like corresponds to this and causes vibration and noise.

Periodic disturbance observer 3 intended to suppress the periodic disturbance dT _n, a system identification model represented by a complex vector for each frequency component by using the inverse system model of the disturbance observer directly the disturbance frequency to be controlled Estimate and compensate.
Thereby, although it is a comparatively simple control configuration, a high suppression effect can be obtained for the target frequency regardless of the order.

Regarding the acquisition of the system identification model P ^ _n , system identification is performed in advance for the plant P _n (= P _An + jP _Bn ) to be controlled prior to the control, and is expressed as an equation (1) in the form of a one-dimensional complex vector. .
P ^ _n = P ^ _An + jP ^ _Bn (1)
However, the subscript n is an n-order component, and all variables are complex vectors expressed as X _n = X _An + jX _Bn .

For example, when the system identification result of 1 to 1000 Hz is expressed by a complex vector every 1 Hz, the system can be expressed by a table composed of 1000 one-dimensional complex vector elements. Alternatively, the system can be expressed by formulating the identification result. In any method, the system model can be expressed with a simple one-dimensional complex vector for a specific frequency component.
Incidentally, a complex vector which is expressed as a system identification model without being limited mentioned in this document _{P ^ n, r n, dT} n, dT ^ n, T n be _{X n = X An + jX Bn} .

Specific control method, by passing the low-pass filter G _F which simplifies Fourier transform to the plant output, to extract a frequency component to be suppressed subject to periodic disturbances. This multiplies the inverse system represented by the reciprocal P ^ _n ^-n the above system identification model, the difference estimating periodic disturbance dT _n from and system identification model d ^ _n the control command value through a G _F To do. The disturbance compensation value by subtracting the estimated period disturbance dT _n from the control command value r _n, suppressing periodic disturbance dT _n. The above flow is a control method for suppressing the periodic disturbance caused by the periodic disturbance observer.
International Publication WO2010 / 024195A1 Torque ripple suppression control method for PM motor based on periodic disturbance observer using complex vector representation, IEEJ Transactions D, Vol. 132, no. 1. p. 84-93 (2012)

  There are many causes of periodic disturbances in an inverter-driven device, and current sensor offset and gain errors are one of them. The offset error mainly causes 1f of the synchronization frequency, and the gain error mainly generates 2f of periodic disturbance.

  Factors that generate torque ripple include the cogging torque of the motor itself in addition to the current sensor error. At this time, let us consider a case where the two purposes of “torque ripple suppression” and “current sensor error correction” are simultaneously aimed.

In the conventional disturbance observer configuration for torque ripple suppression using the detected torque detection value as an input, torque ripple can be suppressed, but current sensor error cannot be corrected. This corresponds to a case where the control command value r _n and a torque command or current command and a detected value from the controlled object 5 as a torque detection value. The applicant has filed a patent application regarding a technique that enables current sensor error correction. In this case, however, the torque ripple generated by the cogging torque or the like remains. It may be possible to simply drive the current sensor error correction and torque ripple suppression in parallel, but if the sensor error factor and the motor side ripple occur in the same dimension, interference between the two causes vibration suppression and current ripple. Falls out of control.

  For this reason, a control system that achieves torque ripple suppression while performing current sensor error correction is required.

An object of the present invention is to provide a periodic disturbance automatic suppression device that suppresses torque ripple while performing current error correction.
The present invention generates a voltage command value by a current control unit from a current command value and a current detection value by a current sensor, and controls a plant via a control device based on the voltage command value.
A plant model unit is provided, and the voltage command value is input to the plant model unit to generate a virtual current value. The virtual current value is input to the periodic disturbance observer of the current error correction control system via the coordinate conversion unit and compensated. And superimposing the calculated compensation value on the current detection value to correct the current detection value by the current sensor,
A periodic disturbance observer for the torque ripple suppression system is provided, and the compensation value is calculated by inputting the plant output torque and the rotational angular velocity to the periodic disturbance observer, and the calculated compensation value is added to the current command value via the coordinate converter. It is characterized by having constituted so.

  Further, the present invention calculates a difference between the compensation value output through the coordinate conversion unit of the torque ripple suppression system and the virtual current value from the plant model unit, and inputs the difference to the coordinate conversion unit of the current error correction control system. It is characterized by comprising.

The present invention further includes a switch provided on the output side of the periodic disturbance observer of the current error correction control system and a switch unit having a memory,
A switch unit provided on the output side of the periodic disturbance observer of the torque ripple suppression system, and when the current sensor error correction by the current error correction control system, the switch unit of the torque ripple suppression system is turned off, and the current error correction control system Turn on the switch of the switch unit, store the compensation value in the memory, perform current sensor error correction based on the compensation value stored in the memory,
The torque ripple suppression system is configured to suppress torque ripple by turning on the switch portion of the torque ripple suppression system after completion of the current sensor error correction.

Further, the present invention generates a voltage command value by a current control unit from a current command value and a current detection value by a current sensor, and controls a plant via a control device based on the voltage command value.
The generated voltage command value and the rotational angular velocity signal of the plant are input to a periodic disturbance observer of a current error correction control system to calculate a disturbance estimated value,
A periodic disturbance observer for a torque ripple suppression system is provided, and a compensation command value is calculated by inputting a plant output torque and a rotational angular velocity to the periodic disturbance observer, and the calculated compensation command value and a periodic disturbance observer for the current error correction control system are calculated. The difference between the estimated disturbance values calculated by the above is used as a compensation value, and the difference between the compensation value and the detected current value is added to the current command value as a compensation value.

The block diagram which shows the 1st Embodiment of this invention. The block diagram which shows the 2nd Embodiment of this invention. The block diagram which shows the 3rd Embodiment of this invention. The block diagram which shows the 4th Embodiment of this invention. The block diagram of a periodic disturbance observer.

  In the present invention, torque ripple is also suppressed along with suppression of periodic disturbance due to current sensor error, which will be described below with reference to the drawings. It should be noted that generation of vibration by the current sensor is not limited to the combination of the inverter and the motor, and is a problem that applies to general control equipment using the current sensor. Therefore, in each embodiment shown below, the control device is an inverter and the controlled object is an example of a motor. However, the present invention is applicable to general control equipment.

FIG. 1 is a block diagram showing a first embodiment of the present invention. The symbols in the figure are as follows.
[Common variables]
T ^* : torque command value, i _dq ^* : i _d , i _q command value, v _dq ^ref : v _d , v _q command value, i _uvw : phase current value, T: output torque value, θ: rotation angle, ω : Rotational angular velocity, i _dq ^sense : current detection i _d , i _q value [current sensor correction side variable]
i _dq ′: post-compensation i _d , i _q , ic _dq ^CT : i _d , i _q compensation value, i ^{^} _dq : virtual i _d , i _q value, I _dqn : n-order harmonics i _d , i _q value, ic _dqn : n-order i _d , i _q compensation value, dI _dq ^* _n : n-order i _d , i _q compensation command value, dI _dqn : n-order i _d , i _q disturbance estimated value [torque correction side variable]
ic _dq ^trq : compensation i _d , i _q value, T _n : n-order harmonics i _d , i _q value, Tc _n : n-order i _d , i _q compensation value, dT ^* _n : n-order torque compensation command value dT _n : n-th order torque disturbance estimated value,
In FIG. 1, reference numeral 1 denotes an inverter that is a control device, 2 is a plant to be controlled (here, a PM motor), 3 and 4 are periodic disturbance observers, and the periodic disturbance observer 3 is a current error correction control system, which is a periodic disturbance observer. 4 is a torque ripple suppression system.

11 converts the conversion unit, the torque command value T ^* d, the current command value of q-axis _{^{i dq * (i d, i}} q) to. The converted current command value i _dq ^* is subtracted with i _dq ′ or added with ic _dq ^trq in the adder / subtractor and input to the current controller 12. The current control unit 12 calculates the voltage command value v _dq ^ref based on the difference between i _dq ^* and i _dq ′ or the added value of i _dq ^* and ic _dq ^trq . A conversion unit 13 converts the d- and q-axis two-phase voltages into three phases and outputs them to the inverter 1, and converts the three-phase current detected by the current sensor 14 into two phases, i _d , i _q Current detection value i _dq ^{sens e} is output to the subtraction unit, and a difference i _dq ′ between i _d and i _{q and} the compensation value ic _dq ^CT is calculated.

  A rotational position sensor 15 detects the rotor rotational angle θ and the rotational angular velocity ω from the encoder waveform abz, outputs them to the conversion unit 13, and multiplies them by a coefficient n to the coordinate conversion unit 17 and the torque ripple suppression system conversion unit 21. Each is output to the coordinate conversion unit 22.
Further, the angular velocity ω is input to the periodic disturbance observers 3 and 4 after being multiplied by a factor n.
Reference numeral 16 denotes a plant model unit (here, a motor model unit), which is an output of the current control unit 12 v_dq ^refInput a command and the virtual current value i ^_dqAnd a torque compensation value ic described later_dq ^trqIs output to the periodic disturbance observer 3 via the coordinate conversion unit 17 as a vibration suppression target. Thereby, since current sensor error correction is not performed, torque ripple suppression is achieved at the same time.
Note that G in the periodic disturbance observers 3 and 4_FIs a low-pass filter.

When an error occurs in the current sensor, the current control unit 12 suppresses the detected vibration on the i _dq ^sense within the response range of the current control unit 12. The vibration component is superimposed on the v _dq ^ref command, and as a result, the output current vibrates and appears as a periodic disturbance. For this reason, no vibration is observed in the i _dq ^sense inside the inverter. However, the virtual current value i ^ _dq in the vibration state can be observed by passing the v _dq ^ref command through the circuit equation of the motor model unit 16. The circuit equation in the motor model unit 16 uses equation (2) when the target is a PM motor.

Here, R is an electric resistance, L _{d is a} d-axis inductance, L _{q is a} q-axis inductance, and Φ is a flux linkage number.

  The parameter accuracy used in the circuit equation in the motor model unit 16 is not required to be high accuracy and may be within the robustness range of the periodic disturbance observer 3. For this reason, a design value or the like is applied, and a system model inside the periodic disturbance observer 3 can be calculated in advance according to this, and accurate acquisition by actual measurement or the like is not necessarily required.

Next, in order to extract the target frequency component of the virtual current value i ^ _dq , the coordinate conversion unit 17 performs harmonic dq conversion of equation (3).

Using the fact that the currents i _d and i _q are always orthogonal, i _dn and i _qn are set to the real part and the imaginary part, respectively, for the complex frequency components to be suppressed by the periodic disturbance observer 3.
_{Treat as} i _dqn = i _dn + ji _qn . From here, the compensation value is calculated according to the control law of the normal periodic disturbance observer 3.
Finally, the coordinate conversion unit 17 converts the compensation value into the dq coordinate system by the coordinate system inverse conversion of equation (4).

The nth-order harmonic current compensation value ic _dqn obtained as a result is added by the vector adding unit 18 to become a compensation value ic _dq ^CT , and this ic _dq ^CT is superimposed on the current detection value i _dq ^sense with a reverse polarity to compensate. A value i _dq ′ is set, and a difference from i _dq ^* is obtained and input to the current controller 12.
Therefore, the periodic disturbance observer 3 becomes a current error correction control system, and the current detection value can be directly compensated by reducing the periodic disturbance due to the current sensor error.

Next, the torque ripple suppression system will be described.
The output torque value T of the PM motor 2 is input to the conversion unit 21. A rotor rotation angle θ detected by the rotational position sensor 15 is input to the conversion unit 21 after being multiplied by a factor n, and the torque value T is converted into a two-phase ab signal corresponding to this θ, and a periodic disturbance is generated. Input to the observer 4.

The periodic disturbance observer 4 also input coefficients n times the angular velocity ω is carried out similar operations as in FIG. 5 calculates a compensation value Tc _n, is output to the coordinate transformation unit 22. The compensation value ic _dq ^trq converted to the coordinates of the d and q axes by the coordinate transformation unit 22 is added to the current command value i _dq ^* and input to the current control unit 12, and the compensation value ic _dq ^trq is the motor model. The signal is superimposed on the opposite polarity to the output i ^{^} _dq of the unit 16 and input to the coordinate conversion unit 17.

  Therefore, according to this embodiment, it is possible to correct the periodic disturbance due to the current sensor error and to suppress the torque ripple.

FIG. 2 is a block diagram showing the second embodiment. The difference from the first embodiment shown in FIG. 1 is that switch portions 19 and 23 are provided.
In the case of the first embodiment shown in FIG. 1, if there is an error in the motor model unit 16, it becomes an interference error of the compensation value. Even in such a case, current error correction and torque ripple suppression can be achieved, but a deviation occurs between the current sensor error correction value and the true value of the sensor error appearing in the compensation value ic _dqn . For this reason, the current sensor error is estimated from the compensation value ic _dqn once acquired, and the current sensor error correction is performed by feedforward, thereby generating a correction error.

Therefore, in FIG. 2, a method of stopping the subtraction of the compensation value ic _dq ^trq of the torque ripple suppression system from the output i ^{^} _dq of the motor model unit 16 and switching the operation of the control system by the switch units 19 and 23 is adopted. . The switch unit 19 includes a switch 19a and a memory 19b.

The procedure of suppression control is as follows.
(1) The switch 19a of the switch unit 19 is turned on, the switch unit 23 is turned off, only the current error correction control system is operated, current sensor error correction is performed, and the compensation value ic _dq ^CT is stored in the memory 19b.
(2) When the current sensor error correction is sufficiently completed, the switch 19a is switched to a terminal on the memory side, and the following compensation value ic _dq ^CT performs current sensor error correction using the compensation value stored in the memory 19b. . At this point, torque ripple is not yet sufficiently suppressed.
(3) Next, when the current sensor error correction is sufficiently completed, the switch unit 23 is turned on, and the remaining torque ripple is controlled to be suppressed.

As a result, the control response is sacrificed and cannot be applied during variable speed operation or the like, but the current sensor error correction ic _dqn value can be accurately obtained at a fixed operating point regardless of the accuracy of the motor model unit 16. Is possible.

FIG. 3 is a block diagram showing the third embodiment. The difference from the first embodiment shown in FIG. 1 is the difference between the compensation value ic _dq ^trq of the torque ripple suppression system and the output i ^{^} _dq of the motor model unit 16. There is no difference calculation.

  In the first and second embodiments, it is configured to prevent interference between the current error correction control system and the torque ripple suppression system assuming suppression of the same order. There is no need to consider. Therefore, simultaneous suppression can be achieved with the simple coupling shown in FIG.

FIG. 4 is a block diagram showing the fourth embodiment. The difference from the first embodiment shown in FIG. 1 is that the motor model unit 16 and the coordinate conversion unit 22 are omitted. That is, the input to the cycle disturbance observer 3 output Tc _n periodic disturbance observer 4 as compensation command value dI _dq ^* _n, the difference between the calculated disturbance estimated value dI _dqn at periodic disturbance observer 3 is obtained. This difference is input to the coordinate conversion unit 17 as the compensation value Ic _dqn .

Further, by omitting the motor model unit 16, the periodic disturbance observer 3 is provided with a parameter changing function based on a circuit equation used in the motor model unit 16 in advance. For example, when acquiring the system identification model P ^ _n in the periodic disturbance observer 3, a function of changing the model by a table or the like for each frequency is provided.

In this embodiment, the overall control basic configuration is the same as in FIG. 1, and the vibration suppression target on the current sensor error correction side is the v _dq ^ref command, and the ripple generated in the voltage command value v _dq ^ref is derived from the sensor error. While suppressing, the torque ripple derived from the motor is also suppressed and input to the sensor error correction as a compensation command. This makes it possible to suppress ripples generated in the same order derived from the motor and the sensor error without causing interference.

  Therefore, according to this embodiment, the current detection value can be accurately corrected while suppressing torque ripple.

Claims (4)

From the current command value and the current detection value by the current sensor, a voltage command value is generated by the current control unit, and the plant is controlled via the control device based on the voltage command value.
A plant model unit is provided, and the voltage command value is input to the plant model unit to generate a virtual current value. The virtual current value is input to the periodic disturbance observer of the current error correction control system via the coordinate conversion unit and compensated. And superimposing the calculated compensation value on the current detection value to correct the current detection value by the current sensor,
A periodic disturbance observer for the torque ripple suppression system is provided, and the compensation value is calculated by inputting the plant output torque and the rotational angular velocity to the periodic disturbance observer, and the calculated compensation value is added to the current command value via the coordinate converter. An apparatus for automatically suppressing periodic disturbances configured to perform   A difference between a compensation value output through the coordinate conversion unit of the torque ripple suppression system and a virtual current value from the plant model unit is calculated and input to the coordinate conversion unit of the current error correction control system. The periodic disturbance automatic suppression device according to claim 1. A switch provided on the output side of the periodic disturbance observer of the current error correction control system and a switch unit having a memory;
A switch portion provided on the output side of the periodic disturbance observer of the torque ripple suppression system;
At the time of current sensor error correction by the current error correction control system, the switch part of the torque ripple suppression system is turned off, and the switch of the current error correction control system switch part is turned on, and the compensation value is stored in the memory and stored in the memory. Current sensor error correction based on the compensation value,
2. The periodic disturbance automatic suppression device according to claim 1, wherein after the current sensor error correction is completed, the torque ripple suppression system is turned on to suppress the torque ripple. From the current command value and the current detection value by the current sensor, a voltage command value is generated by the current control unit, and the plant is controlled via the control device based on the voltage command value.
While inputting the generated voltage command value and the rotational angular velocity of the plant into a periodic disturbance observer of a current error correction control system to calculate a disturbance estimated value,
A periodic disturbance observer for a torque ripple suppression system is provided, and a compensation command value is calculated by inputting a plant output torque and a rotational angular velocity to the periodic disturbance observer, and the calculated compensation command value and a periodic disturbance observer for the current error correction control system are calculated. A periodic disturbance automatic suppression device configured to add the difference between the estimated disturbance value calculated by the above equation as a compensation value and add the difference between the compensation value and the detected current value to the current command value.

Images