JP5488043B2 - Motor torque control device - Google Patents

Description

  The present invention relates to a motor torque control device, and more particularly to suppression of periodic disturbance of torque output and suppression of electric / mechanical resonance in a motor control device that generates torque output of an arbitrary waveform.

  In principle, the motor generates torque ripple (torque pulsation), which causes various problems such as vibration, noise, adverse effects on ride comfort, and electrical / mechanical resonance. In particular, an embedded magnet PM motor (IPMSM), which has become popular in recent years, generates a combination of cogging torque ripple and reluctance torque ripple. As a countermeasure, various methods for superimposing a compensation current for canceling the torque ripple on the torque command have been studied.

  However, for example, in the method of performing feedforward compensation using a mathematical analysis model, there is a concern about the influence of analysis errors. Further, in the method of storing the feedback learning control result at the steady operating point and performing feedforward compensation, it takes time to appropriately adjust the control parameter for each operating point, and online compensation becomes difficult. Further, the method for reducing the current ripple is not always optimally suppressed from the viewpoint of torque ripple. In addition, torque ripple observer compensation methods have been studied, but the characteristics during variable speed operation and on-line feedback suppression verification have been insufficient.

  The inventors of the present application have already proposed a feedback suppression control method using an axial torque meter for the purpose of highly accurately suppressing torque ripple, which is a cause of electrical / mechanical resonance, in response to the above problems (for example, Non-Patent Document 1). reference). This control method focuses on the periodicity of torque ripple and constructs a control system that compensates for each pulsation frequency component, and also has a function that automatically adjusts parameters to respond quickly to changes in the operating state using the system identification result. The details of this control method will be described below.

(1) Basic Configuration of Torque Ripple Suppression Control Device FIG. 8 is a control block diagram of a conventional torque ripple suppression control device. The figure is applied to a system in which a load is torque-excited by a motor.

A motor 1 that is a torque ripple generation source and some load device 2 are coupled by a shaft 3, and its shaft torque is measured by a torque meter 4 and input to a torque ripple suppression device 5. Moreover, the rotor position (phase) information of a motor is input using rotational position sensors 6, such as a rotary encoder. The torque ripple suppression device 5 includes 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. 8, in consideration of the 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.

It is known that torque ripple (torque pulsation) periodically occurs according to the rotor position due to the structure of the motor. Therefore, means for extracting a torque ripple frequency component in synchronism with the motor rotation is used to convert the torque ripple of arbitrary order n into cosine and sine coefficients T _An and T _Bn [Nm]. The exact measurement means for torque ripple frequency components includes Fourier transform, but if importance is placed on the ease of operation, a low-pass filter can be passed through a single-phase harmonic rotation coordinate system based on the rotation phase θ [rad]. A torque ripple frequency component can be extracted.

The torque ripple suppression device 5 performs torque ripple suppression control using the cosine and sine coefficients T _An and T _Bn described above, and the cosine / sine coefficients I _An and I _Bn [ampere] of the compensation current iqc ^* [ampere] of an arbitrary frequency component. Is generated. Conversion to the compensation current iqc ^* is obtained by the following equation (2) using the same rotation phase θ as that at the time of conversion, and this compensation current is superposed on the q-axis current command value and normal vector control is performed.

FIG. 9 shows the torque ripple cosine and sine coefficients T _An and T _Bn obtained from the shaft torque T _det and the rotation phase θ, and the compensation current cosine coefficient I _An and sine coefficient I _Bn obtained from these and the rotation speed ω. It is a control block diagram of the torque ripple suppression apparatus which calculates | requires the compensation electric current of periodic external suppression. The symbols in the figure have the following meanings.

T ^* : Torque command value, T _det : Torque detection value, T _An : n-th order torque pulsation extraction component (cosine coefficient), T _Bn : n-th order torque pulsation extraction component (sine coefficient), ω: Rotation speed detection value, θ : Rotation phase detection value, iqc ^* : torque ripple compensation current, id: d-axis current detection value, id ^* : d-axis current command value, iq: q-axis current detection value, iq ^* : q-axis current command value, iu. iv. iw: u, v, w-phase current, iqo ^* : q-axis current command value (before compensation current superposition), I _An : n-order compensation current cosine coefficient, l _Bn : n-order compensation current sine coefficient, abz: rotation sensor signal . Note that the subscript n is an nth-order component torque ripple.

In FIG. 9, the command value conversion unit 11 converts the torque command value T ^* into the d-axis and q-axis current command values Id ^* and Iqo ^* of the rotation dq coordinate system in vector control. In general, conversion formulas and tables that realize maximum torque / current control are used. Current vector control unit 12 suppresses the torque ripple those superimposed torque pulsation compensation current iqc ^* the q-axis current command value Iqo ^* as q-axis current command value iq ^*. In the example of FIG. 9, the compensation current i _qc is superimposed on the q-axis current command value, but it 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 current vector control unit 12 drives the load device 14 by performing a current vector control operation on a general orthogonal rotating coordinate system d-axis q-axis and driving the motor (IPMSM) 13 by vector control. The coordinate conversion unit 15 converts the three-phase alternating currents iu, iv, iw and the motor rotation phase θ detected by the current sensor 16 into currents id, iq in a dq axis orthogonal rotation coordinate system synchronized with the motor rotation coordinates. The rotation phase / speed detection unit 17 converts the rotation sensor signal abz of the rotation position sensor 18 such as an encoder into information on the rotation speed ω and the rotation phase θ.

The torque pulsation frequency component extraction unit 19 extracts torque periodic disturbance for each pulsation frequency component from the shaft torque detection value T _det detected by the shaft torque meter 20 and the rotation phase θ. A representative means is Fourier transform. The method for extracting the pulsation component is arbitrary, but means such as equations (3) to (5) will be used as an example of simplifying the calculation.

£: Laplace transform, ω _f : Pulsation extraction low-pass filter cutoff frequency [rad / s], s: Laplace operator The torque ripple suppression control unit 21 is a coordinate system synchronized with the torque ripple frequency component, and its cosine coefficient component I _An and sine Each coefficient component I _Bn is obtained. As a representative form of the torque ripple suppression control unit 21, a periodic disturbance observer compensation method or a compensation current Fourier coefficient learning control method can be used.

The compensation current generator 22 generates a compensation current command value iqc ^* by the above equation (2) and superimposes it on the q-axis current command value. In the figure, the compensation current command value is superimposed on the q-axis current command value, but it can be replaced with a d-axis current command value, a current command value for both the d-axis and the q-axis, a torque command value, and the like.

(2) System Identification The system configuration as shown in FIG. 8 is a multi-inertia torsional resonance system due to the moment of inertia of the PM motor 1, the load device 2, the torque meter 4, the coupling 3, and the like. When the detected value of the shaft torque is fed back, since there are a plurality of resonance / anti-resonance frequencies, the suppression control parameter must be appropriately determined according to the operation state. If the learning time of the control parameter is long, there is a risk of increasing the electric / mechanical resonance phenomenon, so a quick automatic adjustment function is necessary.

Therefore, in Non-Patent Document 1, in order to derive a variable nominal control parameter adapted to the rotational speed change, the system transfer characteristic from the output value to the input value of the torque ripple suppressing device 5 in FIG. 8, that is, the compensation current command in FIG. The frequency transfer characteristic from the value iqc ^* to the detection value T _det of the shaft torque detector 4 is identified. The system identification method is arbitrary, but the shaft torque detection value T _det when a Gaussian noise signal is given to iqc ^* in an open loop is measured for 20 seconds at a calculation period of 100 μs, and the frequency is calculated from the ratio of input and output power spectral densities. The result of non-parametric estimation of the transfer function is shown in FIG. 10 (actual machine characteristics including mechanical system, inverter current response, torque meter response, dead time, etc.). In addition, the result of parametric identification in the case of approximating a four-inertia system from the tendency of frequency transfer characteristics is also shown. There are various optimization methods for approximation, but errors in amplitude characteristics up to 1 kHz in the frequency domain were evaluated, and constrained nonlinear minimization (sequential quadratic programming) was performed.

In FIG. 9, in order to construct a control system with coordinates synchronized with the torque ripple frequency, only an arbitrary frequency transfer characteristic is extracted from the system identification result of FIG. In the steady state, the amplitude / phase transfer characteristic of the system synchronized with the torque ripple frequency can be expressed by a one-dimensional complex vector. Therefore, the system characteristic _Psys in the control system of FIG. 9 is defined as the following equation (6).

P _Am : Real part of the system characteristic, P _Bm : Imaginary part of the system characteristic, m: Frequency element number of the system identification table For example, the system characteristic from 1 to 1000 [Hz] is expressed by equation (3) for each IHz. In this case, the system identification table can be constructed from the elements of 1000 complex vectors. Only one complex vector is always used in the control system, and P _Am and P _Bm are instantaneously read from the identification table according to changes in the rotational speed (torque ripple frequency change), and converted into complex vectors by linear interpolation. The identified results are applied to suppression control. In addition, in order to define the axis | shaft of the real part and imaginary part on the basis of a rotation phase, the cosine coefficient in (5) Formula respond | corresponds to a real part component, and a sine coefficient corresponds to an imaginary part component.

(3) Compensation current Fourier coefficient learning control method This is a torque ripple suppression control method described as method 1 in Non-Patent Document 1 described above, which is obtained as a Fourier coefficient of a torque ripple frequency component, and from this, the compensation current is calculated by the above equation (2). Find iqc ^* . In this control method, a system transfer function of a frequency component synchronized with the torque ripple frequency is expressed by a one-dimensional complex vector, and a real part and an imaginary part of the torque ripple of an arbitrary frequency component are extracted by Fourier transform or the like. By applying the cosine and sine Fourier coefficients to the real and imaginary parts of the complex vector, a feedback suppression control system is constructed.

  The compensation current coefficient is obtained by an IP (proportional / integral) learning control method. The proportional / integral gain is determined by the model matching method so that the closed loop characteristic of the IP suppression control system matches the pole arrangement of an arbitrary standard system reference model. In addition, since the parameters are automatically adapted using the system identification result and the rotation speed information, the implementation to the multi-inertia resonance system is facilitated.

  Saves the amplitude and phase of the compensation current signal when suppression is completed at an arbitrary steady operating point (steady torque and steady rotational speed), and implements it at multiple operating points to create a two-dimensional table of torque and rotational speed Implement as At this time, it is possible to input the torque / rotational speed information into the table, generate a compensation current from the read compensation current amplitude / phase data, and suppress feedforward.

(4) Periodic disturbance observer compensation method This is a torque ripple suppression control method described as method 2 in Non-Patent Document 1 described above. Since the control parameter automatic adjustment method in the compensation current Fourier coefficient learning control method suppresses disturbance through the adjustment of the IP control gain, the responsiveness to variable speed operation decreases. For this reason, it is recommended that the learning results be tabulated in advance to suppress feedforward.

  Since the periodic disturbance observer compensation method of the present method directly estimates the torque ripple disturbance using the concept of the periodic disturbance observer, it is possible to improve the above responsiveness problem. Therefore, torque ripple can always be suppressed by online feedback even for a system having variable speed and load fluctuation. Similarly to the compensation current Fourier coefficient learning control method, the system identification result expressed by a one-dimensional complex vector is used to provide a function for automatically adjusting the inverse model of the periodic disturbance observer. It has a feature that makes it easy to implement.

FIG. 11 is a calculation block diagram of the periodic disturbance observer compensation method. In the figure, dI _An ^* : n-th order periodic disturbance current real part (cosine coefficient) command value, dI _Bn ^* : n-th order periodic disturbance current imaginary part (sine coefficient) command value, iqcn: n-order compensation current, dI _An : Real part (cosine) component estimated value of nth order periodic disturbance, dI _Bn : Imaginary part (sine) component estimated value of nth order periodic disturbance, I _An : Real part of nth order compensation current (cosine coefficient), I _Bn : n-order compensation current imaginary part (sine coefficient).

  Since the figure shows only the control system synchronized with the torque ripple frequency, the characteristics of the system are represented by a one-dimensional complex vector. That is, the real system is expressed by the following equation (7), and the system identification result is expressed by equation (8). The estimated value in the equation (8) is indicated by adding a “^” symbol to the top of P, but in the specification, it is indicated as “P ^”.

P _An : System real part of n-th order torque ripple frequency component, P _Bn : System imaginary part of n-th order torque ripple frequency component, P ^ _An : System real part estimated value of n-th order torque ripple frequency component, P ^ _Bn : n-th order torque ripple frequency Estimated value of system imaginary part of component The low-pass filter transfer function of the torque ripple extractor in the figure is represented by the following equation (9) from the equation (5).

FIG. 11 has the same configuration as that of a general conventional disturbance observer. However, since attention is paid only to periodic disturbance, the system characteristic is expressed by a one-dimensional complex vector as shown in Equation (7). The inverse system P ^ sys ^-1 can be simply indicated by the reciprocal of the equation (8) using the system identification result.

The periodic disturbance observer estimates the real part component and the imaginary part component of the periodic disturbance (torque ripple) after performing the above complex vector calculation. The periodic disturbance estimated value real part dI _An and imaginary part dI _Bn may be given as compensation currents so as to cancel the disturbance components as shown in FIG. Usually, by setting the periodic disturbance current command values I _An ^* and I _Bn ^* to zero, the disturbance current of the frequency component can be suppressed.

Kanno et al., “Examination of torque ripple suppression control method focusing on periodic disturbance of PM motor”, 2009 IEEJ Industrial Application Division Conference, I-615-618, Date: August 31-September 2, 2009 Sun, venue: Mie University

  In a motor control device that generates an arbitrary torque waveform by oscillating and superimposing sine wave torque commands of multiple frequency components, the torque waveform resonates when the torque excitation frequency matches the resonance point of the electromechanical system. Causes various problems such as vibration, noise, equipment damage, and measurement problems. In addition, torque periodic disturbance of the motor causes similar problems due to mechanical resonance.

  The compensation current Fourier coefficient learning control method and the periodic disturbance observer compensation method described in Non-Patent Document 1 can basically suppress torque ripple disturbance, but torque resonance occurs in the system due to the above-described torque excitation or the like. . That is, although it corresponds to suppression of periodic disturbance, it does not correspond to suppression of the resonance phenomenon of the electric / mechanical system by a torque command value applied by torque excitation or the like.

  Furthermore, in the compensation current Fourier coefficient learning control method, it is necessary to tabulate the compensation current in order to be able to suppress torque ripple online, but this compensation current table method cannot cope with fluctuations in system control parameters.

  An object of the present invention is to provide a motor torque control device capable of suppressing on-line periodic disturbance of motor torque output and electrical / mechanical resonance in a motor control device that generates torque output of an arbitrary waveform such as torque excitation. There is to do.

  In order to solve the above problems, the present invention provides a motor torque control device that controls the output of a motor with a torque command value having an arbitrary waveform, and estimates torque periodic disturbance from the torque output of the motor directly by an observer. By correcting the command value to suppress torque periodic disturbance, the resonance phenomenon of the electrical / mechanical system due to the frequency component of the torque output is identified as a system transfer function for each frequency component from the torque command value to the torque detection value, and this frequency A torque command value is generated by a resonance suppression table or a resonance suppression calculation using the reciprocal of the identification result for each component.

  Also, the torque command value of an arbitrary waveform is separated into a torque component other than DC and a torque component other than DC, the torque component of DC is converted into a d-axis q-axis current command value, and the torque component other than DC is cycled by the observer. When a periodic disturbance is obtained by expressing a periodic disturbance by a complex vector, it is decomposed into a real part component and an imaginary part component and input to the observer as a periodic disturbance current command value.

  From the above, the present invention is characterized by the following configurations.

(1) In a torque control device for a motor provided with a torque control circuit for controlling output of a motor for driving a load device to a torque command value having an arbitrary waveform,
A periodic disturbance suppression control means for estimating torque periodic disturbance directly from the torque output of the motor with an observer, correcting the torque command value with this estimated value and suppressing the torque periodic disturbance;
The resonance phenomenon of the electrical / mechanical system due to the frequency component of the torque output is identified as a system transfer function for each frequency component from the torque command value to the torque detection value, and the resonance using the reciprocal of the identification result for each frequency component is identified. A mechanical resonance suppression control means for generating a torque command value by a suppression table or a resonance suppression calculation is provided.

  (2) The mechanical resonance suppression control means expresses the system identification result by an approximate mathematical expression of a system characteristic.

(3) The torque control circuit is configured to control the motor current by converting the torque command value into a d-axis q-axis current command value of a rotating coordinate system in vector control,
The periodic disturbance suppression control means, based on the system identification result from the q-axis current command value to the power detection value, uses the reciprocal thereof to calculate the torque command value of only the q-axis current command value for each frequency component. It is characterized by generating.

  (4) The mechanical resonance suppression control means separates a torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component. It is generated as a direct current component of the d-axis q-axis current command value, and a torque command value other than the direct current is converted into a q-axis current command value considering resonance suppression in the resonance suppression table or the resonance suppression calculation.

  (5) The mechanical resonance suppression control means separates an arbitrary waveform torque command value having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component, and the torque component of the DC component is d The torque component other than the direct current is converted into a torque command value considering mechanical resonance characteristics by the resonance suppression table or the resonance suppression calculation.

(6) The mechanical resonance suppression control means separates the torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component. The torque component other than DC is converted into the q-axis current command value, and the real part component dI _An ^* (cosine coefficient component) and the imaginary part when the observer obtains the periodic disturbance by expressing the periodic disturbance as a complex vector It is characterized in that it is decomposed into a component dI _Bn ^* (sine coefficient component) and inputted to the observer as a periodic disturbance current command value.

(7) The mechanical resonance suppression control means separates a torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component, and the torque component of the DC component is d When converting to an axis q-axis current command value, extracting only frequency components synchronized with the torque ripple periodic disturbance from torque components other than DC, and the observer expressing the periodic disturbance by a complex vector to obtain the periodic disturbance The real part component dI _An ^* (cosine coefficient component) and the imaginary part component dI _Bn ^* (sinusoidal coefficient component) are decomposed and input to the observer as a periodic disturbance current command value.

  (8) When the mechanical resonance suppression control unit and the periodic disturbance suppression control unit generate torque output of an arbitrary waveform by superimposing arbitrary torque command values having a plurality of frequency components including a DC component, In addition, a torque command value for each arbitrary frequency component and a current command value in a complex vector representation are generated independently.

  As described above, according to the present invention, the torque periodic disturbance is directly estimated by the observer from the torque output of the motor and the torque command value is corrected to suppress the torque periodic disturbance. The resonance phenomenon of the system is identified as a system transfer function for each frequency component from the torque command value to the torque detection value, and the torque command value is calculated using the resonance suppression table or resonance suppression calculation using the reciprocal of the identification result for each frequency component. Since it is generated, periodic disturbance suppression and mechanical resonance suppression of the torque output of the motor can be performed online in a motor control device that generates torque output of an arbitrary waveform in the motor, such as a torque excitation device.

  Also, the torque command value of an arbitrary waveform is separated into a torque component other than DC and a torque component other than DC, the torque component of DC is converted into a d-axis q-axis current command value, and the torque component other than DC is cycled by the observer. When the periodic disturbance is expressed by a complex vector and decomposed into a real part component and an imaginary part component and input to the observer as a periodic disturbance current command value, the torque ripple frequency and the torque command frequency are Unstable operation due to interference in case of coincidence can be eliminated.

A control block diagram of a torque control device (embodiment 1). The block diagram of a periodic disturbance observer. A control block diagram of a torque control device (second embodiment). A control block diagram of a torque control device (embodiment 3). The block diagram of a periodic disturbance observer. A control block diagram of a torque control device (embodiment 4). The control block diagram of a torque control device (embodiment 5). The block diagram of the conventional torque control apparatus. The control block diagram of the conventional torque control apparatus. The example of the frequency transfer function of a torque control apparatus. The block diagram of the system identification by a periodic disturbance observer.

(Embodiment 1)
A basic configuration diagram of this embodiment is shown in FIG. FIG. 2 shows a calculation block configuration of a periodic disturbance observer which is a representative form of the torque ripple suppression control unit in FIG.

In this embodiment, FIG. 1 differs from FIG. 9 as mechanical resonance suppression control means for suppressing periodic resonance of torque by the periodic disturbance observer shown in FIG. 2 and simultaneously suppressing resonance of the electric / mechanical system. A resonance suppression table 23 for converting the shaft torque command Tsh ^* into a torque command value T ^* considering the mechanical resonance characteristics is provided.

Here, a method of realizing the resonance suppression table 23 will be described. The resonance suppression table 23 is configured based on the system identification result (not the identification result but the system characteristic may be expressed by an approximate expression or the like, but in the present embodiment, an example using a precisely obtained identification result is considered. ), An identification input “torque command value T ^* ” to an identification output “torque detection value T _det ” is identified as a system transfer function for each frequency component, and is configured using the reciprocal of the identification result for each frequency component. Since system identification is a general technique, details of the method are not particularly limited. For example, white noise is given as an identification input signal to the torque command value T ^*, and the output signal (T _det ) at that time is observed and recorded. If the frequency transfer function is obtained from the input / output recorded data, the system transfer characteristic (identification result) for each frequency component can be obtained.

  The identification result is expressed in a table by expressing it as a one-dimensional complex vector for each frequency component as shown in the following equation (12). m represents a table element number representing a frequency component, and N represents the number of elements in the table. When actually used, only a one-dimensional complex vector corresponding to a desired excitation frequency component is extracted from the table and used.

In the equation (12), N is an arbitrary natural number that determines the frequency resolution of the table. For example, when N = 1000 and the table is configured for each IHz, 1 to 1000 Hz can be expressed in 1 Hz increments. P _Am : real part m-th element of system identification result, P _Bm : imaginary part m-th element of system identification result.

Since P _Tm expressed by the above equation (12) indicates the transfer characteristic from the torque command T ^* to the torque detection value T _det in the frequency component corresponding to the m-th element, its reverse calculation value, that is, the reverse characteristic P _Tm ^When a desired excitation torque command value Tsh ^* is input via ⁻¹ , it is possible to generate a torque command value T ^* in consideration of the system resonance characteristics in advance. Since P _Tm ⁻¹ which is the reciprocal of the equation (12) is the set data of the reciprocal of the one-dimensional complex vector, it can be easily calculated.

Therefore, the table of the system inverse characteristic P _Tm ⁻¹ calculated in advance is given to the resonance suppression table 23 of FIG. The frequency component extracted from the resonance suppression table 23 is matched with the frequency component of the excitation torque command value. The resonance suppression table 23 described above can be expressed by a functional expression using the rotational speed ω as a parameter, and the torque command T ^* can be obtained online by calculation according to the functional expression.

The torque ripple suppression control unit 21 has the same configuration as the periodic disturbance observer compensation method described above. If the disturbance current command values dI _An = 0 and dI _Bn = 0, the periodic disturbance is learned and suppressed online. it can.

  According to this embodiment, even if the excitation torque command coincides with the resonance point of the electro-mechanical system, the shaft torque waveform can be controlled safely and satisfactorily to a desired value without causing a dangerous torque resonance phenomenon. Can do. Furthermore, with regard to the periodic disturbance of torque, it is possible to simultaneously realize both periodic disturbance suppression and target value response by simultaneously performing suppression control online by an observer.

  In general, the multi-inertia resonance system is a high-order complex system, and the controller is often required to perform complicated calculations. If this embodiment is used, since the inverse model characteristic is also represented by a one-dimensional complex vector, there is an advantage that the suppression control system can be designed relatively easily.

(Embodiment 2)
When the motor is an interior permanent magnet synchronous motor (IPMSM), it is customary to effectively utilize the reluctance torque using the d-axis current. For example, the ratio of the d-axis current and the q-axis current is controlled so that the maximum torque can be obtained. In general, torque commands are converted into id and iq current command values using theoretical conversion formulas and adjustable conversion tables.

  In the above embodiment, the vector control is performed by converting the torque command including the excitation frequency component into the id and iq current command values. That is, both id and iq current commands have an excitation frequency component. The IPMSM has a complicated torque generation mechanism depending on the load and the rotational speed because of its structure, and is likely to generate a torque error. When d-axis and q-axis currents are vibrated to such a motor, there is a possibility that torque having a more complicated frequency component is generated due to the influence of the above-described error and torque ripple characteristics.

  The simplest torque equation of IPMSM is expressed by equation (13). However, since id and iq are multiplied on the right side, if there is an excitation frequency component in both, a double frequency is generated. Also, since there is actually torque ripple. A simple approximate expression such as expression (13) cannot accurately represent the frequency component included in the torque.

T: Torque, Φ: Number of flux linkages by permanent magnets, Ld: d-axis inductance, Lq: q-axis inductance, p: number of pole pairs As described above, the torque generated by the motor is complicated due to the various causes described above. Contains frequency components. Therefore, in the present embodiment, the vibration is performed using only the q-axis current in order to reduce the adverse effects of the error and interference between the vibration frequencies of the d-axis and the q-axis current. FIG. 3 is a basic configuration diagram of the present embodiment, and a difference from FIG. 1 is that a shaft torque command separating unit 24 is added.

The shaft torque command separation unit 24 separates the direct current component T ₀ ^* and the excitation component Tvib ^* (a plurality of frequency components other than the direct current) from the shaft torque command value Tsh ^* of an arbitrary waveform (that is, including a plurality of frequency components). To do. The separation method is arbitrary. For example, when generating a command value of an arbitrary waveform, the command value of the DC component and other frequency components may be separately commanded in advance, or even a mixed command value may be a high-pass filter (high-pass filter). ) Can be used to separate components other than direct current.

The DC component T ₀ ^* of the torque command separated as described above is converted into the d-axis current command value id ^* and the q-axis current command value (DC component) iqo ^* via the normal torque-id, iq current conversion unit 11. . On the other hand, the excitation torque command value Tvib ^* uses the resonance suppression table 23A to suppress the resonance phenomenon caused by the excitation torque command value. However, the resonance suppression table 23A used here is different from that of the above-described embodiment.

In this embodiment, in order to convert the vibration torque command into the q-axis current command value, the system identification result P _iq from the vibration current command value iqvib ^* to the torque detection value T _det shown in the following equation (14) is used. The reciprocal P _iq ⁻¹ (inverse model) is given as a resonance suppression table. (The basic principle description is as shown in the first embodiment.)

P _Aiqm : Real part m-th element of system identification result, P _Biqm : Imaginary part m-th element of system identification result As for torque ripple periodic disturbance suppression, disturbance current command values dl _An and dI are the same as in the first embodiment. _{If Bn is set} to zero, periodic disturbances can be learned and suppressed online. Then, as shown in FIG. 3, the excitation current command value iqvib ^* and the torque ripple compensation current iqc ^* considering resonance suppression are both superimposed on the q-axis current command value to generate iq ^* .

  According to this embodiment, by using torque excitation by the q-axis current command while separating from the DC torque component, torque waveform distortion and torque error due to interference of torque ripple and d-axis / q-axis current excitation can be reduced. Can be reduced.

(Embodiment 3)
In the first and second embodiments, it is possible to realize a system that suppresses torque ripple periodic disturbance online and does not cause electrical / mechanical resonance even with respect to the excitation torque command value. However, when the torque ripple frequency and the excitation torque command frequency coincide with each other, the torque ripple suppression control system functions as a periodic disturbance up to the frequency component desired to be excited. Therefore, the desired condition cannot be obtained under the above conditions, and an unstable operation may occur.

  In the embodiments after this embodiment, a torque control device that can solve the interference problem between the torque ripple suppression control system and the excitation torque resonance suppression system is proposed.

FIG. 4 shows a basic configuration diagram of this embodiment, and FIG. 5 shows a calculation block of a periodic disturbance observer, which is a representative form of the torque ripple suppression control unit 21 in FIG. In FIG. 4, the excitation frequency component extraction unit 25 obtains a DC component T ₀ ^* and an excitation component Tvib ^* (a plurality of components other than DC) from the shaft torque command value Tsh ^* of an arbitrary waveform (that is, including a plurality of frequency components). Frequency component). The separation method is arbitrary. For example, when generating a command value of an arbitrary waveform, the command value of the DC component and other frequency components may be separately commanded in advance, or even a mixed command value may be a high-pass filter (high-pass filter). ), Or a component other than direct current can be separated using a Fourier transform or a frequency component extraction method as shown in the equations (3) to (5).

The DC component T ₀ ^* of the shaft torque command value separated as described above is converted into the d-axis current command value id ^* and the q-axis current command value (DC component) iqo ^* via the torque-id, iq current conversion unit 11. . On the other hand, the excitation torque command value Tvib ^* suppresses the resonance phenomenon caused by the excitation torque command value using the resonance suppression table 23B. However, unlike the above-described embodiment, the resonance suppression table 23B used here converts the shaft torque command value Tsh ^* into a torque command value considering the mechanical resonance characteristics.

The resonance suppression table 23B is configured based on the system identification result (although it may be an approximate expression indicating the system characteristics instead of the identification result, in this embodiment, an example using a precisely obtained identification result is considered). It is identified as a system transfer function for each frequency component from the input “compensation current command value iqc ^* ” to the identification output “torque detection value T _det ”, and is constructed using the reciprocal of the identification result for each frequency component. Since system identification is a general technique, details of the method are not particularly limited. For example, white noise is given to the compensation current command value iqc ^* as an identification input signal, and the output signal (T _det ) at that time is observed and recorded. If the frequency transfer function is obtained from the input / output recorded data, the system transfer characteristic (identification result) for each frequency component can be obtained.

  The identification result is expressed as a table by expressing it as a one-dimensional complex vector for each frequency component as shown in the following equation (15). m represents a table element number representing a frequency component, and N represents the number of elements in the table. When actually used, only a one-dimensional complex vector corresponding to a desired excitation frequency component is extracted from the table and used.

In equation (15), N is an arbitrary natural number that determines the frequency resolution of the table. For example, when N = 1000 and the table is configured every 1 Hz, 1 to 1000 Hz can be expressed in 1 Hz increments. P _Aiqm : Real part m-th element of system identification result, P _Biqm : Imaginary part m-th element of system identification result P _iq expressed by the above equation (15) is a compensation current command in a frequency component corresponding to the m-th element Since the transfer characteristic from iqc ^* to the torque detection value T _det is shown, if the desired excitation torque command value Tsh ^* is input via the reverse calculation value, that is, the reverse characteristic P _iq ⁻¹ , the system resonance characteristic is obtained. A torque command value considering in advance can be generated. P _iq ^−1, which is the reciprocal of equation (15), can be easily calculated because it is set data of the reciprocal of the one-dimensional complex vector.

Therefore, the table of the system inverse characteristic P _iq ⁻¹ calculated in advance is given to the resonance suppression table 23B of FIG. The frequency component extracted from the resonance suppression table 23B is matched with the frequency component of the excitation torque command value. The resonance suppression table can also be expressed by a functional expression with the rotation speed ω as a parameter.

The DC component T ₀ ^* of the torque command separated and extracted as described above is a normal torque-id, d-axis current command value id ^* via the iq current conversion unit 11, q-axis current command value (DC component) iq ₀ ^*. Convert to On the other hand, the vibration component Tvib ^* is converted into the vibration current command value iqvib ^* in consideration of mechanical resonance using the resonance suppression table 23B. In the method of the second embodiment shown in FIG. 3, the excitation current command value iqvib ^* is directly superimposed on the q-axis current command value. However, in this embodiment, the real part / imaginary part separation unit 26 uses the arbitrary frequency component. When the excitation current command value is expressed as a complex vector, it is decomposed into a real part component dI _An ^* (cosine coefficient component) and an imaginary part component dI _Bn ^* (sine coefficient component), and the torque ripple suppression control unit 21 receives a periodic disturbance. Input as current command value. That is, when the excitation current command value of an arbitrary n-order frequency component is expressed by the following equation (16), the periodic disturbance current command value is given as iq _An = dI _An ^* and iq _Bn = dl _Bn ^* . The torque ripple suppression control unit 21 is equivalent to the periodic disturbance observer proposed in the first and second embodiments.

As described above, by setting the excitation current command value iqvib ^* to the periodic disturbance current command value iq _An = dI _An ^* and iq _Bn = dl _Bn ^* , the torque ripple compensation by the periodic disturbance observer can be performed as desired. It functions to suppress disturbances other than the excitation component while generating an oscillating current. The real component I _An and the imaginary component I _Bn of the excitation current command value whose disturbance is suppressed are converted into a compensation current command value iqc * by the calculation according to the following equation (16) by the compensation current generator 22, and q It is superimposed on the shaft current command value iq0 ^* .

  According to the present embodiment, even if the excitation torque frequency component and the torque ripple frequency component coincide with each other, the resonance phenomenon is suppressed by avoiding interference between the excitation torque resonance suppression control system and the torque ripple suppression control system. The torque can be controlled to a desired value.

(Embodiment 4)
In the third embodiment, in a state where the shaft torque excitation frequency component is known in advance, the real part and the imaginary part of the excitation current command value are separated and used as the periodic disturbance current command value of the torque ripple suppression control system. The present embodiment proposes a system that avoids an interference problem with the torque ripple suppression control system even when the frequency component of the shaft torque command value is unknown.

FIG. 6 is a basic configuration diagram of the present embodiment. This is basically the same as in the third embodiment, but the excitation current command value iqvib ^* , which is the output of the resonance suppression table 23B, is directly superimposed on the q-axis current command value, and the torque pulsation synchronization frequency component extraction unit 27 adds it. Only the frequency component synchronized with the torque ripple periodic disturbance is extracted from the vibration current command value iqvib ^* and set as the periodic disturbance current command values dI _An ^* and dl _Bn ^* of the torque ripple suppression control.

  The torque pulsation synchronization frequency component extraction unit 27 may basically perform the same processing as the torque pulsation extraction unit. That is, extraction is performed as follows using the rotational phase θ.

£: Laplace transform, ω _f : Pulsation extraction cutoff frequency, iq _An : Real part component (cosine coefficient) of excitation current command value, iq _Bn : Imaginary component (sine coefficient) of excitation current command value
The real part / imaginary part component of the excitation current command value obtained by the above equations (17) to (19) may be given as it is as the real part / imaginary part component of the periodic disturbance current command value of the torque ripple suppression control system. . That is, dI _An ^* = iq _An and dl _Bn ^* = iq _Bn may be set.

  According to this embodiment, even if an excitation torque command value that does not know the frequency component or is provided with an aperiodic frequency component is given, the current command value that basically considers resonance suppression by the excitation torque command value Can be generated. Further, even when there is a moment synchronized with the torque ripple frequency, the frequency component of the excitation current at that time is extracted to give the periodic disturbance current command value, so that the problem that the suppression control system interferes can be avoided at the same time. .

(Embodiment 5)
In the present embodiment, a method for realizing the frequency components of the third or fourth embodiment in parallel and simultaneously is proposed. A basic configuration diagram is shown in FIG. 7, and an excitation frequency component extraction unit 25A, a resonance suppression table 23C, a torque pulsation synchronization frequency component extraction unit 27A, a torque ripple suppression control unit 21A, a torque pulsation frequency component extraction unit 19A, and a compensation current generation unit 22A. Then, the command value for each frequency component, torque pulsation, etc. are obtained. Also, determine the vibration current command value Iqvib ^* by the addition of vibration current command value iqvibl ^* ~iqvibn ^* frequency components in the adder 28.

7, Tvibl ^{* to} Tvibn ^* are torque excitation command values of different arbitrary frequency components, iqvibl ^{* to} iqvibn ^* are excitation current command values of different arbitrary frequency components, and di _A1 ^{* to} di _An ^* are The real part component (cosine coefficient) of the periodic disturbance current command value of different arbitrary frequency components, di _B1 ^{* to} di _Bn ^* are the imaginary part component (sine coefficient) of the periodic disturbance current command value of different arbitrary frequency components, T _A1 ^* ~ T _An ^* is the real part component (cosine coefficient) of the periodic disturbance torque ripple of different arbitrary frequency components, T _B1 ^{* to} T _Bn ^* are the imaginary part component (sine coefficient) of the periodic disturbance torque ripple of different arbitrary frequency components, I _A1 ^{* to} I _An ^* are real part components (cosine coefficient) of the excitation current command value in which the periodic disturbance is suppressed, and I _B1 ^{* to} I _Bn ^* are imaginary parts of the excitation current command value in which the periodic disturbance is suppressed. component (sine coefficients), iqc ^* is periodic disturbance compensation A vibration current command value.

  An arbitrary waveform can be realized by superposing a plurality of frequency components. Therefore, in the present embodiment, the configuration of the third or fourth embodiment is made to correspond to the torque excitation command values of a plurality of frequency components. Here, the configuration of the fourth embodiment is parallelized as a representative form. The method for achieving both the torque ripple periodic disturbance suppression and the suppression of the resonance phenomenon by the excitation signal is the same as the method described in the fourth embodiment.

In the present embodiment, as shown in FIG. 7, since it is assumed that the shaft torque command value has a plurality of frequency components, the frequency components Tvibl ^{* to} Tvibn ^* are extracted and input to the resonance suppression table 23C. since vibration current command value considering resonance characteristics in this table iqvibl ^* ~iqvibn ^* it is obtained, superimposing them adder 28 vibration current command value obtained by adding at Iqvib ^* the q-axis current command value. Next, in order to prevent interference with the torque ripple suppression control system, the torque pulsation synchronization frequency component extraction unit 19A extracts the torque pulsation synchronization component included in iqvib ^* . The extraction method is the same as that of the fourth embodiment, and for example, the above equations (17) to (19) may be used. The extracted real part / imaginary part current signals are directly input to the torque ripple suppression control system as periodic disturbance current command values di _A1 ^{* to} di _An ^* and di _A1 ^{* to} di _An ^* . The periodic disturbance compensation currents I _A1 ^{* to} I _An ^* and I _B1 ^{* to} I _Bn ^* are generated and added in the respective orders using the above equation (2) as the compensation current iqc ^* , and the q-axis current Superimpose on the command value. Other components are basically the same as those in the fourth embodiment.

  As described above, by using this embodiment, it is possible to generate an arbitrary torque waveform without causing a resonance phenomenon by superimposing excitation torques of a plurality of frequency components. In addition, torque ripple periodic disturbance can be suppressed at the same time.

  Each embodiment shows a case of a control device that obtains torque excitation in the motor output, but it can be applied to a motor control device that generates a torque output of an arbitrary waveform in the motor to obtain an equivalent effect. it can.

DESCRIPTION OF SYMBOLS 11 Command value conversion part 12 Current vector control part 13 Motor 14 Load apparatus 15 Coordinate conversion part 16 Current sensor 17 Rotation phase / speed detection part 18 Rotation position sensor 19, 19A Torque pulsation frequency component extraction part 20 Axis torque detector 21, 21A Torque ripple suppression control unit 22, 22A Compensation current generation unit 23, 23A, 23B, 23C Resonance suppression table 24 Shaft torque command separation unit 25, 25A Excitation frequency component extraction unit 26 Real part / imaginary part separation unit 27, 27A Torque pulsation synchronization Frequency component extractor 28 Adder

Claims (8)

In a motor torque control device provided with a torque control circuit that outputs and controls a motor that drives the load device to a torque command value having an arbitrary waveform,
A periodic disturbance suppression control means for estimating torque periodic disturbance directly from the torque output of the motor with an observer, correcting the torque command value with this estimated value and suppressing the torque periodic disturbance;
The resonance phenomenon of the electrical / mechanical system due to the frequency component of the torque output is identified as a system transfer function for each frequency component from the torque command value to the torque detection value, and the resonance using the reciprocal of the identification result for each frequency component is identified. A motor torque control apparatus comprising mechanical resonance suppression control means for generating a torque command value by a suppression table or resonance suppression calculation.   2. The motor torque control device according to claim 1, wherein the mechanical resonance suppression control unit expresses the system identification result by an approximate mathematical expression of a system characteristic. 3. The torque control circuit is configured to control the motor current by converting the torque command value into a d-axis q-axis current command value of a rotating coordinate system in vector control,
The periodic disturbance suppression control means, based on the system identification result from the q-axis current command value to the power detection value, uses the reciprocal thereof to calculate the torque command value of only the q-axis current command value for each frequency component. The motor torque control device according to claim 1, wherein the motor torque control device is generated.   The mechanical resonance suppression control unit separates a torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than DC and a torque component other than DC, and the torque command value for DC is d-axis q 4. A direct current component of an axial current command value is generated, and a torque command value other than direct current is converted into a q-axis current command value considering resonance suppression in the resonance suppression table or resonance suppression calculation. The motor torque control device according to any one of the above.   The mechanical resonance suppression control means separates a torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component, and the DC component torque component is a d-axis q-axis. 5. The torque command value is converted into a current command value, and torque components other than direct current are converted into a torque command value in consideration of mechanical resonance characteristics by the resonance suppression table or resonance suppression calculation. The motor torque control apparatus described. The mechanical resonance suppression control means separates a torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component, and the DC component torque component is a d-axis q-axis. The torque component other than the direct current is converted into a current command value, and the real component dI _An ^* (cosine coefficient component) and the imaginary component dI _Bn when the observer obtains the periodic disturbance by expressing the periodic disturbance with a complex vector. ^* torque control apparatus for a motor according to any one of claims 1 to 5, and decomposed into (sine coefficient component), characterized in that input as periodic disturbance current command value to the observer. The mechanical resonance suppression control means separates a torque command value having an arbitrary waveform having a plurality of frequency components including a DC component into a torque component other than a DC component and a torque component other than a DC component, and the DC component torque component is a d-axis q-axis. Real part when converting to a current command value, extracting only frequency components synchronized with the torque ripple periodic disturbance from torque components other than DC, and the observer expressing the periodic disturbance by a complex vector to obtain the periodic disturbance 6. The component dI _An ^* (cosine coefficient component) and the imaginary part component dI _Bn ^* (sine coefficient component) are decomposed and input to the observer as a periodic disturbance current command value. The motor torque control device according to claim 1.   The mechanical resonance suppression control means and the periodic disturbance suppression control means are parallel and independent when generating an arbitrary waveform torque output by superimposing arbitrary waveform torque command values having a plurality of frequency components including a DC component. The torque control device for a motor according to any one of claims 1 to 7, wherein a torque command value for each arbitrary frequency component and a current command value in a complex vector representation are generated.

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