WO2010024195A1 - Electric motor disturbance suppression device and disturbance suppression method - Google Patents

Abstract

Provided is a device and method that can suppress disturbances of complex electric motor systems and are capable of stable control wherein periodic torque pulsations, etc. are suppressed. A controller (5) that converts a torque command value of an electric motor (1) to d and q axial current command values of a rotation coordinate system in vector control and controls the torque of the electric motor by controlling the current of an inverter (7) according to the current command values, detects periodic torque pulsations of a load device (2) and the electric motor as direct current values from the detected axial torque values using a Fourier transform as a frequency component extraction means, estimates periodic disturbances of the frequency components by means of a periodic disturbance observer, and superimposes compensation currents on the d and q axial current command values so that the periodic disturbances are suppressed, thereby suppressing disturbances. The frequency characteristics of the torque control system are represented as an aggregate of the complex vectors by system identification, and the periodic disturbance observer estimates periodic disturbances using the complex vectors corresponding to arbitrary frequencies.

Description

Disturbance suppression device and disturbance suppression method for electric motor

The present invention relates to an apparatus and a disturbance suppressing method for suppressing torque pulsation (disturbance) generated in an electric motor in a torque control apparatus for an electric motor that drives a rotating machine.

Rotating electrical machines such as electric motors have structural magnetic flux distortion and cogging torque, and therefore generate torque pulsations that contribute to vibration and noise according to the rotation. In addition, various factors such as the magnetic imperfection of the motor structure, the response / current error of the inverter power supply that drives it, and the characteristics of the mechanical system are complicatedly related. In addition, when a multi-inertia system is configured between the motor and the load, the mechanical resonance point and the torque pulsation frequency component coincide with each other, generating an excessive shaft torsion torque, which adversely affects operating characteristics and damages the system. There is a danger of.

In order to solve these problems, a disturbance suppression method using a disturbance observer has been considered for a long time. The torque pulsation is regarded as a disturbance, and the disturbance is estimated by, for example, a general minimum-dimensional observer method and added to the command value so as to suppress it. However, such a disturbance observer has a frequency band condition that can be suppressed, and the suppression effect generally decreases in a high frequency region.

In order to alleviate the problem of the disturbance observer described above, a control method that suppresses periodic disturbances such as torque pulsation using a disturbance observer compensator and repetitive control has been proposed (see, for example, Patent Document 1). In this method, in a frequency band that cannot be sufficiently suppressed only by a disturbance observer compensator, a strong periodic disturbance is suppressed by repetitive control, and an aperiodic disturbance is suppressed by using a normal disturbance observer compensator.

Another method is to reduce the harmonic current of the motor. Rotational coordinate transformation is performed that rotates at a frequency that is an integral multiple of the frequency of the fundamental wave component of the current flowing through the motor, and its harmonic current is extracted and suppressed to zero by the PI controller. At this time, a technique has been proposed in which the harmonic velocity electromotive force is regarded as a disturbance, a disturbance observer is configured and added to a command value, and the disturbance is suppressed (for example, see Patent Document 2).

Japanese Patent Gazette No. 2566033 Japanese Patent Gazette No. 35582505

In the above-mentioned Patent Document 1, a general repetitive controller is used in combination to alleviate the problem of disturbance observer. That is, paying attention to the fact that the torque pulsation of the motor has periodicity, periodic disturbances are repeatedly compensated by the controller, and other non-periodic disturbances are suppressed by using a normal disturbance observer. However, it is not guaranteed that repetitive control in a rotating electromechanical system having complicated mechanical characteristics is stable in the entire frequency band. Therefore, the compensation signal may be returned to cause a divergence phenomenon.

On the other hand, in Patent Document 2, a rotational coordinate transformation of a harmonic that rotates at an integral multiple of the fundamental wave component frequency of the current flowing through the motor is performed, and the harmonic current of that component is extracted and is zeroed by the PI controller. Oppressed. At this time, the harmonic electromotive force is regarded as a disturbance, and a disturbance observer for estimating the disturbance is configured and added to the current command value on the harmonic rotation coordinates to suppress the harmonic current. Although this method can suppress the harmonic current flowing in the motor, the torque pulsation cannot always be suppressed with high accuracy, and it does not cope with complicated electromechanical characteristics such as a multi-inertia system and an inverter response.

An object of the present invention is to provide a disturbance suppressing device and a disturbance suppressing method for an electric motor that can suppress disturbance of a complicated electric motor system and can perform stable control while suppressing periodic torque pulsation.

In order to solve the above-mentioned problems, the present invention performs a Fourier transform for each arbitrary pulsation frequency component, configures a periodic disturbance observer compensator so that two Fourier coefficients are 0, and compensates the compensation current with a vector control inverter. Is superposed on the current command value, and has the following configuration and method.

(1) The controller converts the command value of the electric motor into d and q-axis current command values of a rotating coordinate system in vector control, and controls the motor by current control of the inverter according to the current command values.
The controller detects a periodic pulsation of the motor as a DC value by a frequency component extraction means of Fourier transform, estimates a periodic disturbance on the frequency component by a periodic disturbance observer compensator, and suppresses the periodic disturbance. As described above, a periodic disturbance observer compensator that superimposes a compensation current on the d and q axis current command values is provided with means for suppressing the disturbance.

(2) The frequency characteristic of the control system composed of the inverter and the motor is expressed as a set of complex vectors by system identification, and the periodic disturbance observer compensator estimates the periodic disturbance using a complex vector corresponding to an arbitrary frequency. Means are provided.

(3) The periodic disturbance observer compensator includes a disturbance observer filter having different characteristics on the command value and detected value sides.

(4) The present invention is characterized by comprising means for variably setting the characteristics of the periodic disturbance observer compensator and the Fourier transform unit in accordance with the rotational speed.

(5) In a steady operation state at an arbitrary frequency, the Fourier coefficient of the pulsation compensation current is learned and recorded in advance by the periodic disturbance observer compensator, and the Fourier coefficient is similarly processed at a plurality of operating points to obtain the rotational speed and A compensation current Fourier coefficient table using torque as an input parameter or an approximation function is generated, and means for providing a pulsation compensation current by feedforward control is provided.

(6) The compensation current Fourier coefficient table or the approximate function includes a detected temperature value of the motor as a parameter.

(7) Periodic disturbance suppression by the feedforward control is performed only when the rotational speed or torque command value exceeds a certain rate of change, and switching to periodic disturbance suppression by feedback is performed during other steady or quasi-steady operation. It is characterized by.

(8) The periodic disturbance observer compensator is applied to different frequency components, and parallelizes them to simultaneously suppress periodic disturbances of a plurality of frequency components.

(9) The periodic disturbance is a detected value of shaft torque of the motor, and the disturbance of shaft torque of the motor is suppressed.

(10) The periodic disturbance is a pulsation component of the electric motor frame, and suppresses the electric motor frame disturbance.

(11) The periodic disturbance is a pulsation component of the rotation speed detection value or rotation position detection value of the motor, and suppresses the disturbance of the speed of the motor or the disturbance of the rotation position.

(12) The periodic disturbance is a pulsating component of the electric current of the motor, and suppresses the disturbance of the electric current of the electric motor.

(13) The amplitude M and phase φ of the torque ripple compensation current i _qc ^* learned in the steady operation state (steady torque command / steady rotation speed) designated when the torque ripple suppression control is executed by the controller are used as the torque command T _ref ^* And an amplitude / phase compensation table for generating a two-dimensional amplitude table and a phase table with the rotational speed ω as a variable,
The amplitude M and phase φ at that time are read out from the amplitude / phase compensation table from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor, and the amplitude M and phase φ and the rotational phase θ of the motor at that time are read out. A compensation current generation unit that generates a table compensation current i _qct ^* = M · sin (nθ + φ) using
Compensation current synthesis means for synthesizing the online compensation current i _qc ^* and the table compensation current i _qct ^* when torque ripple suppression control is executed by the controller and superimposing them on the d and q axis current command values is provided. It is characterized by.

(14) The amplitude M and phase φ of the torque ripple compensation current i _qc ^* learned in the steady operation state (steady torque command / steady rotation speed) designated when the torque ripple suppression control is executed by the controller are used as the torque command T _ref ^* And an amplitude / phase compensation table for generating a two-dimensional amplitude table and a phase table with the rotational speed ω as a variable,
The amplitude M and the phase φ at that time are read from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor from the amplitude / phase compensation table, and the amplitude M and the phase φ and the compensation current amplitude by the controller Combining means for synthesizing the command value M ^* and the compensation current phase command value φ ^* to generate a combined compensation current amplitude value M ′ and a combined compensation current phase value φ ′;
Compensation current generation for generating a table compensation current i _qc ^* = M ′ · sin (nθ + φ ′) using the combined compensation current amplitude value M ′, the combined compensation current phase value φ ′ and the rotational phase θ of the motor at that time And a section.

(15) Compensation current cosine Fourier coefficient table value A and compensation current sine Fourier coefficient table of torque ripple frequency components learned in a steady operation state (steady torque command / steady rotation speed) designated when torque ripple suppression control is executed by the controller A Fourier coefficient compensation table for generating a two-dimensional Fourier coefficient compensation table using the value B as a variable for the torque command T _ref ^* and the rotational speed ω;
The Fourier coefficient table values A and B at that time are read out from the Fourier coefficient compensation table from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor, and the Fourier coefficient table values A and B and the controller Compensation current cosine Fourier coefficient A ^* and compensation current sine Fourier coefficient B ^* for extracting torque ripple frequency components by Fourier transform are synthesized to generate compensation current cosine Fourier coefficient synthesis value A ′ and compensation current sine Fourier coefficient synthesis value B ′. A synthesis means to
Using the Fourier coefficient composite value A ′, the compensation current sine Fourier coefficient composite value B ′, and the rotational phase θ of the motor at that time, the amplitude M = √ (A ′ ² + B ′ ² ) and the phase φ = tan ⁻¹ ( B ′ / A ′) table compensation current i _qc ^* = M · sin (nθ + φ).

(16) The compensation table, synthesizing means, and compensation current generating section are provided with means for individually generating an amplitude M and a phase φ or a Fourier coefficient with a plurality of order components and generating a compensation current by synthesizing them according to these orders. It is characterized by that.

(17) In the method in which the controller converts the command value of the motor into a d, q-axis current command value of a rotating coordinate system in vector control, and controls the motor by current control of the inverter according to the current command value.
The controller detects a periodic pulsation of the motor as a direct current value by a frequency component extraction means of Fourier transform, estimates a periodic disturbance on the frequency component by a periodic disturbance observer, and suppresses the periodic disturbance. Further, the disturbance is suppressed by a periodic disturbance observer compensator that superimposes a compensation current on the d and q axis current command values.

(18) The frequency characteristic of the control system including the inverter and the motor is expressed as a set of complex vectors by system identification, and the periodic disturbance observer compensator estimates the periodic disturbance using a complex vector corresponding to an arbitrary frequency. It is characterized by that.

(19) The amplitude M and phase φ of the torque ripple compensation current learned in the steady operation state (steady torque command / steady rotational speed) designated when the torque ripple suppression control is executed by the controller, or the compensation current cosine Fourier of the torque ripple frequency component A coefficient table value A and a compensation current sine Fourier coefficient table value B are generated as a two-dimensional compensation table using the torque command T _ref ^* and the rotational speed ω as variables,
The amplitude M and phase φ or Fourier coefficient table values A and B at that time are read from the compensation table from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor, and the amplitude M and phase φ or Fourier Using the coefficient table values A and B and the rotational phase θ of the motor at that time, a table compensation current is generated,
The compensation current and the table compensation current when torque ripple suppression control is executed by the controller are combined and superimposed on the d and q axis current command values.

The block diagram of the disturbance suppression apparatus of the electric motor which concerns on this invention.

The basic block diagram of the disturbance suppression which concerns on this invention.

The block diagram of the torque pulsation compensation apparatus by a system identification apparatus.

The block diagram of a disturbance suppression control system.

Explanatory drawing of the effect of disturbance suppression.

The block diagram of the disturbance suppression control system of Embodiment 2. FIG.

FIG. 6 is a configuration diagram of a disturbance suppression control system of a third embodiment.

The block diagram of the disturbance suppression control system of Embodiment 4. FIG.

FIG. 10 is a configuration diagram of a disturbance suppression control system according to a fifth embodiment.

FIG. 10 is a configuration diagram of a disturbance suppression control system of a seventh embodiment.

FIG. 10 is a configuration diagram of a disturbance suppression device according to an eighth embodiment.

FIG. 10 is a configuration diagram of a disturbance suppression device according to a ninth embodiment.

FIG. 10 is a configuration diagram of a disturbance suppression device according to a tenth embodiment.

The block diagram of the disturbance suppression apparatus of Embodiment 11. FIG.

FIG. 18 is a configuration diagram of a disturbance suppression device according to a twelfth embodiment.

The block diagram of the disturbance suppression apparatus of Embodiment 13. FIG.

The block diagram of the disturbance suppression apparatus of Embodiment 14. FIG.

(Basic configuration)
Before describing an embodiment of the present invention, a basic configuration of a disturbance suppression device according to the present invention will be described.
FIG. 1 shows the configuration of a disturbance suppression device for an electric motor according to the present invention. An electric motor 1 that is a generation source of torque pulsation and some load device 2 are coupled by a shaft 3, and the shaft torque is measured by a torque meter 4 and input to a controller 5. Moreover, the rotor position information of the electric motor is input using a rotational position sensor 6 such as a rotary encoder. The controller 5 is equipped with torque pulsation suppression means, and gives the inverter 7 a command value obtained by adding a torque pulsation compensation current to the current command value generated based on the torque command value (or speed command value). In the example of FIG. 1, in consideration of current vector control by the inverter 7, the d-axis and q-axis current command values id ^* and iq ^* on the rotation coordinates (orthogonal dq axes) synchronized with the rotation of the motor are given. Yes.

The controller 5 detects torque pulsation from the torque detection value by the shaft torque meter 4, but this form is only an example, and vibration detection by an acceleration sensor installed in the frame, rotation speed fluctuation detection by an encoder, etc., or current In place of detection of current pulsation by a sensor, it is possible to suppress disturbance of the motor shaft, disturbance of the frame of the motor, suppression of disturbance of the speed of the motor or disturbance of the rotational position, and suppression of disturbance of the current of the motor.

Torque pulsation is known to occur periodically according to the rotor position due to the structure of the motor. The torque pulsation of the three-phase motor is mainly a frequency 6 × n times the electrical rotation fundamental frequency (n is a positive integer: hereinafter, the 6-fold component is expressed as 6f, the 12-fold component is expressed as 12f, etc.) It is also known that the component becomes large. In addition, 1f and 2f torque pulsations may appear due to incompleteness of the inverter power supply, current sensor offset, and the like. Further, in a system in which axial torsional resonance can occur as shown in FIG. 1, a pulsation component close to the mechanical resonance point is amplified and appears in the detected axial torque value.

In the present invention, the torque pulsation in which these various frequency components are mixed is extracted based on Fourier transform. That is, the controller 5 in FIG. 1 performs a Fourier transform for each arbitrary order on the shaft torque meter detection value T _det using information on the motor rotor phase θ≡. Here, the Fourier series is defined by Equation 1 and Equation 2 below. ω represents an electrical angular frequency, and _Tr represents one cycle of a pulsating component that is arbitrarily defined. Note that the integration of the Fourier transform can be simply changed to a low-frequency pass filter (low-pass filter) having an arbitrary time constant. That is, any means for extracting a high frequency component (torque pulsation) as a direct current value may be used.

It is noted that the Fourier coefficients T _An and T _Bn expressed by Equation 2 output a DC value if the motor rotation speed and the pulsation component that is a periodic disturbance are constant in an arbitrary period. If some control is given and both of these coefficients are zero and steady, it means that the torque pulsation of the frequency component has been suppressed.

Therefore, in the present invention, the Fourier transform is performed for each arbitrary pulsation frequency component, the periodic disturbance observer compensator is configured so that the two Fourier coefficients are 0, and the compensation current is superimposed on the current command value of the vector control inverter. To do. Hereinafter, a basic configuration of disturbance suppression according to the present invention will be described with reference to FIG.

FIG. 2 develops control blocks based on the system configuration of FIG. The command value conversion unit 11 converts the torque command value T _ref into the d-axis and q-axis current command values I _do and I _qo of the rotation dq coordinate system in vector control (for example, maximum torque control), and converts it into a current command value. Torque pulsation is suppressed by superimposing torque pulsation compensation current. In the example of FIG. 2, the compensation current i _qc is superimposed on the q-axis current command value, but may be applied to the d-axis current or both the d-axis and the q-axis. Alternatively, in a system where interference of dq axis current does not become a problem, a torque pulsation compensation signal may be directly superimposed on the torque command value. The inverter 12 is a general electric motor drive device that realizes current vector control in the d-axis and q-axis converted from the three-phase rotational coordinates, and drives the electric motor load 13.

The sine / cosine wave generator 14 sets the rotor phase angle θ of the motor load 13 and the order n of the pulsating component to be suppressed, and generates a sine / cosine wave having a reference frequency. In the Fourier transform unit 15, the sine / cosine wave and an arbitrary Fourier transform period _Tr are set, and the shaft torque detection value T _det is Fourier transformed based on Equation 2, and the nth-order Fourier coefficients T _An and T _Bn are obtained. Calculate. Here, it is also possible to replace the integration process of the Fourier transform of Formula 2 with a low frequency band pass filter (low pass filter) having an appropriate time constant.

Next, the periodic disturbance observer compensator 16 is configured so that the Fourier coefficients T _An and T _{Bn of} the pulsation component are 0 (that is, the pulsation is suppressed). Details of this portion will be described in an embodiment described later. The outputs I _An and I _Bn of the periodic disturbance observer compensator 16 are the Fourier coefficients of the compensation current signal, and the n-th order sine and cosine waves are respectively multiplied by the multipliers 17A and 17B and inversely converted. That is, it is restored as a compensation current signal having a time waveform. The restored pulsation compensation current iqc ^* is superimposed on the q-axis current command value iq0 ^* of the vector control inverter 7 by an adder.

As described above, instead of directly detecting the shaft torque pulsation, torque estimated by an observer or the like from the inverter current or speed detection value may be used, or the motor housing frame vibration or the like is detected by an acceleration sensor, It is also conceivable to perform vibration suppression.

In the present invention, in order to simplify the explanation of the core control method, an embodiment will be described below by taking as an example a case where torque is directly detected by an axial torque meter or the like.

　ただし、Ｐｓｙｓ＾：同定システム、ｍ：周波数成分の分割要素番号、Ｐ_Am：ｍ番目の要素の同定システム実数部、Ｐ_Bm：ｍ番目の要素の同定システム虚数部 (Embodiment 1)
In the present embodiment, the process starts by grasping in advance the frequency characteristics of the motor drive system. There are various methods for grasping frequency characteristics and system identification, but these are known general techniques, and the present invention is not limited to specific methods. For example, as shown in FIG. 3, the system identification device 18 inputs the white noise signal as a torque pulsation compensation current to the actual system and superimposes it on the current command value in any steady operation state (FIG. 3 shows the q-axis current). Although they are superimposed, they may be d-axis or both). System input / output data is obtained using the detected shaft torque value as a system output signal. It is possible to obtain a frequency transfer function from the pulsation compensation current command value to the shaft torque detection value by spectrum analysis of the frequency response from the input / output time series data. Although it is possible to formulate based on the system identification theory or to obtain parameters based on a physical model (for example, a two-inertia system model), in this embodiment, the frequency transfer function is complex as shown in Equation 3. Expressed as a set of vectors. The elements of the set correspond to complex vectors indicating gain / phase characteristics in each frequency component.

Where Psys ^: identification system, m: frequency component division element number, P _Am : m-th element identification system real part, P _Bm : m-th element identification system imaginary part

Here, the division element number m will be described. For example, if the frequency component necessary for identification is DC to 5 kHz and the resolution is 1 Hz, the number of elements is 5001. Therefore, as m = {0, 1, 2, 3,..., 4999, 5000}, a spectrum analysis result or a system identification result is applied to each element (frequency component). Since the gain / phase characteristic of the system for each frequency component can be expressed by a complex vector on the complex plane, it can be expressed as in Equation 3.

When Fourier transform is used, torque pulsation of an arbitrary frequency component can be extracted with a Fourier coefficient. As shown in Equation 2, since the two Fourier coefficients have orthogonality, if one element of the complex vector of Equation 3 above is extracted focusing on only the system state of any frequency component, its real part and imaginary part Can be compared to two Fourier coefficients. That is, here, the real part is adapted to the cosine Fourier coefficient, and the imaginary part is adapted to the sine Fourier coefficient (for example, the counterclockwise direction is defined as the lag phase, and the polarity is adapted by inverting the polarity of P _Bm ).

From the above, if attention is paid only to the arbitrary frequency component after Fourier transform, the periodic disturbance (torque pulsation) of the frequency component and the pulsation for suppressing it using the complex vector of Equation 3 that means system characteristics The relationship between the Fourier coefficient of the compensation current signal and the detected torque pulsation value can be grasped. In addition, since these relationships are all expressed by a DC component by Fourier transform, the periodic disturbance also becomes a DC value at that frequency.

Here, as shown in FIG. 4, a disturbance suppression control system considering only one arbitrary frequency component is considered, and a periodic disturbance observer compensator for estimating and compensating for the periodic disturbance is configured. That is, an error from the compensation current command value is obtained from the detected axial torque pulsation value via the inverse system of Equation 4 (reciprocal of the complex vector), and the error is regarded as a periodic disturbance current corresponding to the periodic disturbance. Then, the error compensation amount is superimposed as a compensation current command value so as to cancel the disturbance.

FIG. 4 will be described. The characteristic P _sys (n-order component) of the real system 19 is considered to be represented by a one-dimensional complex vector at a certain frequency component, as in Equation 4. The compensation current i _qcn is given to the input, and the pulsation compensation torque T _cn is generated so as to cancel the periodic disturbance torque T _rpln . Since the torque pulsation is extracted by Fourier transform, the Fourier coefficients T _An and T _Bn of the detected torque pulsation value are obtained via the response transfer function G _FT of the Fourier transform unit 20. These are replaced with the complex vector T _An + T _Bn i.

Next, the nth-order disturbance observer 21 obtains current input information including the disturbance current using the reciprocal of the frequency transfer function identified in Formula 4 (not including the disturbance), and subtracts the compensation current command value therefrom. Thus, the periodic disturbance currents dI _An and dI _Bn are estimated. _GOBS is used to insert an arbitrary filter (for example, a low-pass filter) to suppress the influence of residual pulsation and disturbance estimation error during Fourier transform extraction and stabilize pulsation compensation.

The periodic disturbance is estimated as described above, and the compensation current i _qcn is generated by subtracting the currents dI _An and dI _Bn corresponding to the disturbance from the target value (usually 0 when the periodic disturbance is suppressed).

FIG. 5 shows the disturbance suppression effect when the present embodiment is applied. From the top, the waveforms are the detected shaft torque value [Nm], the torque pulsation Fourier coefficient [Nm], the compensation current Fourier coefficient [A], and the torque pulsation amplitude evaluation value [Nm]. As an example, only the 12th pulsation component is shown.

Referring to the shaft torque waveform, it can be seen that the torque pulsation appears larger than the steady torque before the suppression starts, but the pulsation is greatly reduced after the suppression. It can be seen that the sine / cosine Fourier coefficient of the torque pulsation is 0 after suppression.

(Embodiment 2)
In the present embodiment, the filter of the nth-order disturbance observer 21 in FIG. 4 is separated on the command value side and the detection value side. A configuration example of this embodiment is shown in FIG.

For example, the filter characteristics of G _OBS and G _LPF can be set separately in consideration of pulsation extraction by Fourier transform, communication / calculation delay time, and the like.

According to the present embodiment, the disturbance suppression characteristics can be obtained in which the filter characteristics on the command value side and the detection value side of the periodic disturbance observer are set separately, and the detection system delay and the like are taken into account.

(Embodiment 3)
In the present embodiment, in consideration of the case where the rotation speed of the motor changes, both the Fourier transform cycle and the cutoff frequency of the disturbance observer filter are made variable using the rotation speed detection value (or estimated value) of the motor. FIG. 7 is a configuration example of this embodiment.

When the rotational speed changes, one element (one-dimensional complex vector) extracted from the complex vector set of Formula 3 and applied also changes. Therefore, (P _sys ) ⁻¹ is also variable according to the speed. Further, the cut-off frequency of the observer filter _GOBS and the Fourier transform response _GFT are also made variable in accordance with the rotation speed, and are adapted so that a stable pulsation suppression effect is always obtained.

According to the present embodiment, it is possible to suppress periodic disturbance by sequentially adapting to rotational speed fluctuations.

(Embodiment 4)
When a frequency component is extracted using Fourier transform or the like, the extraction time is required for a certain period, and a sufficient disturbance suppression response speed may not be obtained. For example, when trying to cope with variable speed operation and quasi-steady torque fluctuation exceeding the response, the suppression effect may be insufficient.

Therefore, in the present embodiment, after suppressing the torque pulsation using the periodic disturbance suppressing means described above, two Fourier coefficients of the pulsation compensation current are recorded in the memory in the steady state at the arbitrary operating point. Such a memory recording process is performed in advance in the same manner at each operating point, and a compensation current Fourier coefficient table having the rotational speed and the torque command value as inputs is created. Instead of the table, an approximate function using the rotation speed and the torque command value as parameters may be used. After generating the compensation table, two compensation current Fourier coefficients are read from the table according to the operating point, and a pulsation compensation current is generated and applied by feedforward.

FIG. 8 is a configuration example of this embodiment. The difference from FIG. 2 is that the rotational speed W _m is obtained from the rotor phase angle θ by the rotational speed calculation unit 22 and the compensation current Fourier coefficient I is obtained from this and the torque command value T _ref by the compensation table 23 (or compensation approximate function). _{Reads An} and I _Bn .

According to this embodiment, since the Fourier coefficient of the pulsation compensation current is learned in advance and can be suppressed only by reading the coefficient, it is possible to instantly cope with a sudden change in the operating point such as the rotational speed and torque. Is possible.

(Embodiment 5)
In this embodiment, in addition to the fourth embodiment, the temperature of the electric motor is detected, a change in system characteristics due to a temperature change is detected, and a table or an approximate function is formed at each operating point as in the fourth embodiment. .

FIG. 9 is a configuration example of this embodiment. The part different from FIG. 8 is to measure the temperature t of the motor load 13 and incorporate this temperature t as a compensation parameter of the compensation table 23.

According to this embodiment, it is possible to cope with a system having a strong temperature dependency.

(Embodiment 6)
In the present embodiment, the periodic disturbance suppression control in which shaft torque detection is fed back and the feedforward compensation method based on the learned compensation table (or approximate expression) are switched and used. A rotation speed or a torque command value is used as a reference for switching control.

For example, when looking at the change rate of the rotational speed or torque command value and inputting a command value change rate that is equal to or higher than the Fourier transform response, switch to the compensation table method. In quasi-steady operation with a small change rate, periodic disturbance suppression means by constant feedback is used.

Since the compensation means by feedforward may not be able to sufficiently cope with perturbation changes of system characteristics depending on the system to be applied, the feedforward operation can be minimized by using the means for switching the operation state as described above. Can be.

(Embodiment 7)
The above embodiments have been periodic disturbance suppression control means for any one pulsation frequency component, but if the configurations in each embodiment are parallelized, frequency components of a plurality of periodic disturbances can be suppressed. Is possible.

A configuration diagram of this embodiment is shown in FIG. 10, where 24 ₁ to 24 _n are control elements for suppressing pulsation components according to the first to nth orders of the Fourier series, and the compensation current signals i _qc1 to i _qcn by these are controlled. The signals are superimposed on each other by an adder 25 to obtain a torque pulsation compensation signal i _qc .
According to this embodiment, a plurality of torque pulsations can be suppressed simultaneously. Further, since these can be simultaneously suppressed in parallel, it is an effective means even when disturbance suppression of one frequency component adversely affects periodic disturbance of another frequency component.

(Embodiment 8)
In the embodiments described above, the torque pulsation compensation method or method has been proposed based on the configuration that feeds back the shaft torque, but the object to be fed back can be changed.

In this embodiment, as shown in FIG. 11, the acceleration sensor 8 detects the vibration of the frame / housing of the motor and feeds it back. The disturbance suppression control method is the same as in the above embodiments.

According to the present embodiment, it is possible to suppress the disturbance of the casing of the electric motor.

(Embodiment 9)
In the present embodiment, as shown in FIG. 12, the fluctuation of the phase / speed information provided from the rotational position sensor 6 is detected, and control is performed so as to suppress the fluctuation. The control contents are basically the same as those in the above-described embodiments.

According to this embodiment, periodic speed fluctuations and phase fluctuations can be suppressed.

(Embodiment 10)
In the present embodiment, as shown in FIG. 13, the current sensor 9 detects the current of the three-phase line that supplies power from the inverter 7 to the pulsation compensation target electric motor 1, and suppresses the current disturbance.
According to the present embodiment, the estimated disturbance torque pulsation can be suppressed by suppressing the inverter current disturbance using the detected inverter current value or by using the estimated torque value converted from the inverter current.

(Embodiment 11)
In the torque ripple suppression control according to the above-described embodiments, the Fourier transform is performed for each arbitrary pulsation frequency component, and the periodic disturbance observer is configured so that the two Fourier coefficients are 0, thereby performing stable control in the entire frequency band. The “on-line compensation method” is obtained. According to this online compensation method, torque ripple can be suppressed by always online feedback even for a system having variable speed and load fluctuation. In addition, since it has a function of automatically adjusting the periodic disturbance observer model using the system identification result expressed by a one-dimensional complex vector, it can be implemented in a multi-inertia resonance system.

In addition, since the “online compensation method” is constantly learning, it is possible to cope with changes in the motor and inverter characteristics over time. However, since the learning algorithm always needs to be operated, the computation load is relatively high. Even when the load device of the motor is changed, the system needs to be re-identified, and learning time is required, so it can respond quickly to variable speed operation and torque changes. There is a problem with inferiority.

The eleventh embodiment and the following twelfth to fourteenth embodiments can suppress torque ripple by on-line compensation that can cope with changes in electric motors and inverters over time, and reduce computation load, eliminate the need for re-identification of the system, and have responsiveness. The present invention proposes a control device and method capable of suppressing torque ripple.

FIG. 14 shows a block configuration of the torque control apparatus for an electric motor according to the present embodiment, and shows a case where torque ripple suppression is performed by an on-line compensation method for controlling an inverter of a current vector control method.

In FIG. 14, the current vector control unit 31 of the inverter 7 is synchronized with the motor rotation coordinates by the coordinate conversion unit 33 from the motor drive currents i _u , i _v , i _w detected by the current sensor 32 and the rotor rotation angle θ of the motor 1. The motor current is controlled by comparison with the d and q axis current detection values converted into the current of the dq axis orthogonal rotation coordinate system. The rotor rotation angle θ is obtained from the encoder waveform abz by the rotational position sensor 6 together with the speed ω by the speed / phase detector 34.

The torque / id, iq conversion unit 35 (command value conversion unit 11) determines the d-axis and q-axis current command values i of the rotation dq coordinate system in vector control from the torque command value T _ref from the controller 5 and the motor rotation speed ω. _d ^* (I _do ), i _q0 ^* (I _qo ), and among these current command values, the q-axis current command value i _q0 ^* is superimposed on the torque pulsation compensation current i _qcm to obtain a current vector control command value. .

As in FIG. 1, the controller 5 is equipped with torque ripple suppression control means. Examples of the torque ripple suppression control means include a sine / cosine wave generator 14, a Fourier transform unit 15, and a periodic disturbance observer compensator 16 shown in FIG. 2. The pulsation compensation currents such that the Fourier coefficients T _An and T _{Bn of the} pulsation components become zero are obtained by the multipliers 17A and 17B, and the pulsation compensation current i _qc ^* is the q-axis current command value i _q0 ^* To make a compensation signal.

Here, in the present embodiment, on the basis of the “online compensation method”, a compensation current generation unit that suppresses in a feedforward manner is added using a compensation table learned in advance. As this compensation current generation means, an amplitude / phase compensation table 36 and a compensation current generator 37 are provided.

The amplitude / phase compensation table 36 records the amplitude M and the phase φ of the torque ripple compensation current i _qc ^* learned in the steady operation state (steady torque command / steady rotation speed) designated when the torque ripple suppression control is executed by the controller 5. To do. This operation is similarly recorded at a plurality of steady operation points to generate a two-dimensional amplitude table and phase table using the torque command T _ref ^* and the rotational speed ω as variables. Information between data is interpolated by linear interpolation or the like.

The compensation current generation unit 37 reads the current amplitude M and phase φ from the operating state (torque command / rotation speed) from the amplitude / phase compensation table 36, and the read amplitude M and phase φ are the rotational phase at that time. Table compensation current i _qct ^* = M · sin (nθ + φ) is generated using θ (n is the compensation order). The generated table compensation current i _qct ^* is combined with the online compensation current _iqc ^* to obtain a q-axis current command value i _qcm ^* .
Thus, ^* the table compensation current i _qct, because it generates a compensation current instantaneously from the learned compensation current table to obtain the amplitude and phase, a suitable compensation current even when the speed change or torque change occurs rapidly Can be output. In addition, even if the torque ripple deviates from the characteristics at the time of learning due to changes in ambient temperature or changes in physical properties over time, the online compensation feedback loop works, so the error in the table compensation current can be corrected. .

Embodiment 12
FIG. 15 shows a block configuration of the torque control apparatus for an electric motor according to the present embodiment, and the basic configuration and operation are the same as those in FIG. 14, but errors in the amplitude M and phase φ of the compensation current generated in the compensation table 36 are shown. An online compensation feedback loop is constructed from the controller 5 to correct.

In FIG. 15, M ^* is a compensation current amplitude command value (on-line compensation), φ ^* is a compensation current phase command value (on-line compensation), and the synthesizers 38 and 39 use these as the compensation current amplitude M · phase φ. The compensation current amplitude value (composite value) M ′ and the compensation current phase value (composite value) φ ′ to the compensation current generator 37 are combined.

In the eleventh embodiment, the table compensation current i _qct ^* and the online compensation current i _qc ^* are combined after the generation of the compensation current. However, in the present embodiment, they are combined in the state of amplitude and phase. That is, the compensation table amplitude value M and the compensation table phase value φ are combined with the online compensation amplitude value M ^* and the online compensation phase value φ ^* , respectively, and the combined compensation current amplitude value M ′ and the combined compensation current phase value φ ′. Is generated. The compensation current generator 37 generates a final compensation current i _qc ^* with i _qc ^* = M ′ · sin (nθ + φ ′). (N is the compensation order)

According to the present embodiment, the table error can be grasped and corrected with an intuitively easy-to-understand state quantity such as amplitude and phase, and the compensation current generator 37 can be gathered in one place.

(Embodiment 13)
FIG. 16 shows a block configuration of the torque control apparatus for an electric motor according to the present embodiment, which is replaced with a cosine Fourier coefficient and a sine Fourier coefficient instead of the compensation table amplitude M and phase φ in the twelfth embodiment (FIG. 15). .

The compensation table 40 generates a compensation current cosine Fourier coefficient table value A and a compensation current sine Fourier coefficient table value B according to the torque command T _ref ^* and the rotational speed ω, and the controller 5 calculates the online compensation current cosine Fourier coefficient A ^* . The online compensation current sine Fourier coefficient B ^* is generated, and the synthesizers 38 and 39 synthesize these to obtain a compensation current cosine Fourier coefficient synthesis value A ′ and a compensation current sine Fourier coefficient synthesis value B ′.

The controller 5 equipped with the torque ripple suppression control function basically uses a technique for extracting and suppressing the torque ripple frequency component by Fourier transform (or a similar technique). In FIG. 2, there are real and imaginary components of a complex vector corresponding to two Fourier coefficients, and the amplitude value and phase value of the compensation current are calculated using these components.

In the configuration of FIG. 2, the real part component of the compensation current generated by the periodic disturbance observer compensator 16 is defined as B (I _Bn ), and the imaginary part component is defined as A (I _An ). From these, the amplitude M and the phase φ are obtained as follows.

M = √ (A ² + B ² ), φ = tan ⁻¹ (B / A)

In the eleventh and twelfth embodiments, the compensation table is generated or the online compensation is performed after obtaining the amplitude M and the phase φ. While the compensation current characteristic is easy to understand intuitively, the above-described arithmetic conversion is required. It was.

Therefore, in the present embodiment, as shown in FIG. 16, a compensation table is generated in the state of two Fourier coefficients A and B before being converted into amplitude and phase, and online compensation is also synthesized in the state of the Fourier coefficient. The compensation current i _qc ^* is generated at the final stage. As a result, it is possible to save the labor of the above-described calculation for converting into amplitude / phase and simplify the compensation process.

(Embodiment 14)
In the present embodiment, a method is provided in which any of the configurations of the eleventh to thirteenth embodiments is parallelized to simultaneously suppress torque ripples of multiple order components.

For example, FIG. 17 shows a case where the configuration of the eleventh embodiment is parallelized. (This is the same for the other embodiments, so the explanation is omitted in the drawing.) FIG. 17 shows that the two compensation components 36A and 36B individually generate the amplitude M and the phase φ with the two order components. The two compensation current generators 37A and 37B generate compensation currents for two orders, and simultaneously suppress torque ripple for these two orders. Of course, it is possible to extend the case where three or more orders are simultaneously suppressed.

As described above, according to the present invention, the Fourier transform is performed for each arbitrary pulsation frequency component, the periodic disturbance observer compensator is configured so that the two Fourier coefficients are 0, and the compensation current is set to the current of the vector control inverter. Since it is superposed on the command value, it is possible to suppress disturbances in a complicated electric motor system and to perform stable control in which periodic torque pulsation is suppressed.

Furthermore, based on the “online compensation method”, a compensation current that has been learned in advance is used in combination to generate a compensation current that is suppressed in a feed-forward manner. Torque ripple suppression can be suppressed.

Claims (19)

The controller converts the command value of the motor into d and q-axis current command values of a rotating coordinate system in vector control, and controls the motor by current control of the inverter according to the current command values.
The controller detects a periodic pulsation of the motor as a direct current value by a frequency component extraction means of Fourier transform, estimates a periodic disturbance on the frequency component by a periodic disturbance observer, and suppresses the periodic disturbance. A disturbance suppression device for an electric motor comprising means for suppressing disturbance by a periodic disturbance observer compensator for superimposing a compensation current on the d and q axis current command values. The frequency characteristic of the control system composed of the inverter and the motor is expressed as a set of complex vectors by system identification, and the periodic disturbance observer compensator includes means for estimating the periodic disturbance using a complex vector corresponding to an arbitrary frequency. The disturbance suppression device for an electric motor according to claim 1. 3. The disturbance suppression device for an electric motor according to claim 1, wherein the periodic disturbance observer compensator includes a disturbance observer filter having different characteristics on a command value and detection value side. The disturbance suppression for an electric motor according to any one of claims 1 to 3, further comprising means for variably setting the characteristics of the periodic disturbance observer compensator and the Fourier transform unit in accordance with a rotation speed. apparatus. In a steady operation state at an arbitrary frequency, the periodic disturbance observer compensator previously learns and records the Fourier coefficient of the pulsation compensation current, processes the Fourier coefficient in a plurality of operating points in the same manner, and inputs the rotation speed and torque. The motor disturbance according to any one of claims 1 to 4, further comprising means for generating a compensation current Fourier coefficient table or an approximate function as a parameter and providing a pulsation compensation current by feedforward control. Suppressor. The motor disturbance suppression device according to claim 5, wherein the compensation current Fourier coefficient table or the approximate function includes a temperature detection value of the motor as a parameter. The periodic disturbance suppression by the feedforward control is performed only when the rotation speed or the torque command value exceeds a certain rate of change, and switching to the periodic disturbance suppression by feedback is performed during other steady or quasi-steady operation. The disturbance suppression device for an electric motor according to claim 5 or 6. 8. The periodic disturbance observer compensator is applied to each of different frequency components and parallelized to suppress periodic disturbances of a plurality of frequency components at the same time. A disturbance suppression device for an electric motor according to claim 1. The motor disturbance suppression device according to any one of claims 1 to 8, wherein the periodic disturbance is a shaft torque detection value of the motor and suppresses the disturbance of the shaft torque of the motor. 10. The disturbance suppression device for an electric motor according to claim 9, wherein the periodic disturbance is a pulsation component of the frame of the electric motor, and suppresses the disturbance of the electric motor frame. 10. The electric motor disturbance according to claim 9, wherein the periodic disturbance is a pulsation component of a rotation speed detection value or a rotation position detection value of the motor, and suppresses the disturbance of the speed of the motor or the disturbance of the rotation position. Suppressor. 10. The disturbance suppression device for an electric motor according to claim 9, wherein the periodic disturbance is a pulsation component of the electric current of the electric motor, and suppresses the electric current disturbance of the electric motor. The amplitude M and phase φ of the torque ripple compensation current i _qc ^* learned in the steady operation state (steady torque command / steady rotation speed) designated when the torque ripple suppression control is executed by the controller are used as the torque command T _ref ^* and the rotation speed. An amplitude / phase compensation table for generating a two-dimensional amplitude table and a phase table with ω as a variable;
The amplitude M and phase φ at that time are read out from the amplitude / phase compensation table from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor, and the amplitude M and phase φ and the rotational phase θ of the motor at that time are read out. A compensation current generation unit that generates a table compensation current i _qct ^* = M · sin (nθ + φ) using
Compensation current combining means for combining the online compensation current _iqc ^* and the table compensation current i _qct ^* when the torque ripple suppression control is executed by the controller and superimposing them on the d and q axis current command values is provided. The motor disturbance suppression device according to any one of claims 1 to 12, characterized in that: The amplitude M and phase φ of the torque ripple compensation current i _qc ^* learned in the steady operation state (steady torque command / steady rotation speed) designated when the torque ripple suppression control is executed by the controller are used as the torque command T _ref ^* and the rotation speed. An amplitude / phase compensation table for generating a two-dimensional amplitude table and a phase table with ω as a variable;
The amplitude M and the phase φ at that time are read from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor from the amplitude / phase compensation table, and the amplitude M and the phase φ and the compensation current amplitude by the controller Combining means for synthesizing the command value M ^* and the compensation current phase command value φ ^* to generate a combined compensation current amplitude value M ′ and a combined compensation current phase value φ ′;
Compensation current generation for generating a table compensation current i _qc ^* = M ′ · sin (nθ + φ ′) using the combined compensation current amplitude value M ′, the combined compensation current phase value φ ′ and the rotational phase θ of the motor at that time The electric motor disturbance suppression device according to any one of claims 1 to 12, wherein the electric motor disturbance suppression device is provided. The compensation current cosine Fourier coefficient table value A and the compensation current sine Fourier coefficient table value B of the torque ripple frequency component learned in the steady operation state (steady torque command / steady rotation speed) designated when the torque ripple suppression control is executed by the controller. A Fourier coefficient compensation table for generating a two-dimensional Fourier coefficient compensation table using the torque command T _ref ^* and the rotational speed ω as variables;
Reading said Fourier coefficient table value A and B at that time the torque command T _ref ^* in operating state of the motor from the rotational speed ω from the Fourier coefficients compensation table, and these Fourier coefficient table value A and B, wherein the controller Compensation current cosine Fourier coefficient A ^* and compensation current sine Fourier coefficient B ^* for extracting torque ripple frequency components by Fourier transform are synthesized to generate compensation current cosine Fourier coefficient synthesis value A ′ and compensation current sine Fourier coefficient synthesis value B ′. A synthesis means to
Using the Fourier coefficient composite value A ′, the compensation current sine Fourier coefficient composite value B ′, and the rotational phase θ of the motor at that time, the amplitude M = √ (A ′ ² + B ′ ² ) and the phase φ = tan ⁻¹ ( 13. The electric motor according to claim 1, further comprising a compensation current generation unit that generates a table compensation current i _qc ^* = M · sin (nθ + φ) of B ′ / A ′). Disturbance suppression device. The compensation table, the synthesizing means, and the compensation current generating unit are provided with means for individually generating an amplitude M and a phase φ or a Fourier coefficient with a plurality of order components, and generating a compensation current by synthesizing by each order. The motor disturbance suppressing device according to any one of claims 13 to 15, wherein The controller converts the command value of the motor into a d, q-axis current command value of a rotating coordinate system in vector control, and controls the motor by current control of the inverter according to the current command value.
The controller detects a periodic pulsation of the motor as a direct current value by a frequency component extraction means of Fourier transform, estimates a periodic disturbance on the frequency component by a periodic disturbance observer, and suppresses the periodic disturbance. A disturbance suppression method for an electric motor, wherein disturbance is suppressed by a periodic disturbance observer compensator that superimposes a compensation current on the d and q axis current command values. The frequency characteristic of the control system composed of the inverter and the motor is expressed by a set of complex vectors by system identification, and the periodic disturbance observer compensator estimates the periodic disturbance using a complex vector corresponding to an arbitrary frequency. The disturbance suppression method for an electric motor according to claim 17. Amplitude M and phase φ of torque ripple compensation current learned in steady operation state (steady torque command / steady rotation speed) designated when torque ripple suppression control is executed by the controller, or compensation current cosine Fourier coefficient table value of torque ripple frequency component A two-dimensional compensation table with the torque command T _ref ^* and the rotational speed ω as variables is generated for A and the compensation current sine Fourier coefficient table value B, and
The amplitude M and phase φ or Fourier coefficient table values A and B at that time are read from the compensation table from the torque command T _ref ^* and the rotational speed ω in the operating state of the motor, and the amplitude M and phase φ or Fourier Using the coefficient table values A and B and the rotational phase θ of the motor at that time, a table compensation current is generated,
The motor disturbance according to claim 17 or 18, wherein the compensation current and the table compensation current when torque ripple suppression control is executed by the controller are combined and superimposed on the d and q-axis current command values. Repression method.

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