JP4437354B2 - Electric motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for identifying an electric constant of a motor during operation in order to improve control accuracy in a control device for a power converter that supplies power to an AC motor.
[0002]
[Prior art]
As an example of the prior art, a block diagram of a motor control device that controls the torque of a permanent magnet motor is shown in FIG.
The power converter 1 supplies a three-phase voltage based on the input two-phase voltage commands var and vbr to the permanent magnet motor 2. The current detector 4 detects the primary current of the permanent magnet motor 2, converts it into a current vector in a stationary coordinate, and outputs its components ia and ib.
The speed position detector 3 detects and outputs the direction θ of the permanent magnet of the rotor of the permanent magnet motor 2. The coordinate converter 5 performs rotational coordinate conversion on the current vector output from the current detector 4 based on the direction θ of the permanent magnet, and outputs id and iq. Here, id is a current component in the direction of the permanent magnet (hereinafter referred to as d-axis), and iq is a current component in a direction perpendicular thereto (hereinafter referred to as q-axis). The d-axis current command generator 8 outputs a d-axis current command idr.
The q-axis current command generator 9 receives the q-axis current command iqr from the torque command Tr and the d-axis current command idr,
iqr = Tr / {φ + (Ld−Lq) · idr} (1)
Calculate and output with the following formula. Here, φ is the amount of magnetic flux of the permanent magnet of the permanent magnet motor 2, Ld is the d-axis inductance, and Lq is the q-axis inductance. The current controller 7 outputs voltage commands vdr and vqr that cause the id and iq of the output of the current detector 4 to follow the command values idr and iqr, respectively.
The inverse coordinate converter 6 converts the voltage commands vdr and vqr into voltage commands var and vbr on the stationary coordinates based on the direction θ of the permanent magnet output from the velocity position detector.
With the above control configuration, the output torque of the permanent magnet motor 2 is controlled to follow the torque command Tr.
[0003]
[Problems to be solved by the invention]
As described above, in order for the output torque of the permanent magnet motor 2 to be controlled in accordance with the torque command Tr, the formula (1) needs to be accurately calculated.
For this purpose, the amount of magnetic flux φ of the permanent magnet of the permanent magnet motor 2, the d-axis inductance Ld, and the q-axis inductance Lq must match the actual values, but φ varies depending on the temperature of the permanent magnet. Since Ld and Lq vary depending on the magnitude of current due to magnetic saturation, it is difficult to match φ, Ld, and Lq used in equation (1) with the actual values of the permanent magnet motor 2.
Therefore, it becomes difficult to control the output torque of the permanent magnet motor 2 in accordance with the torque command Tr.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the motor control device that controls the output torque and rotation speed of the motor to those command values,
A current detector that detects a primary current of the motor, converts the current into a vector, and outputs the vector;
A speed position detector for detecting a rotation speed or a rotation angle of the electric motor;
A current model magnetic flux calculator that inputs a primary current vector of the current detector output and a rotation speed or rotation angle of the speed position detector output, and calculates a primary interlinkage magnetic flux vector of the motor by an electrical constant;
A voltage detector that detects or estimates a primary voltage of the electric motor, converts the voltage into a vector, and outputs the vector;
A timing generator that outputs a pulse of a predetermined period, and among the two consecutive pulse outputs from this timing generator, the older one is time t0 and the newer one is time t1, and the primary voltage vector of the voltage detector and the current Using the primary current vector of the detector output and the primary winding resistance value of the motor, the fluctuation of the primary linkage flux vector of the motor between the times t0 and t1 is obtained by time integration with an initial value of zero. Voltage model magnetic flux fluctuation calculator to calculate,
The current model magnetic flux calculator output at time t0 is φi0, the current model magnetic flux calculator output at time t1 is φi1, and the output of the voltage model magnetic flux fluctuation calculator is Δφv at time t1. The primary flux linkage vector φv1 of
φv1 = Δφv · φi1 / (φi1-φi0)
A voltage model magnetic flux estimator to be calculated by
A constant adjuster for adjusting an electric constant of the electric motor used in the current model magnetic flux calculator so that φv1 of the voltage model magnetic flux estimator and φi1 of the current model magnetic flux calculator output coincide with each other; .
[0005]
When the motor is a permanent magnet motor, the electric constant of the motor used in the current model magnetic flux calculator is parallel to the magnetic flux amount φ of the permanent magnet of the permanent magnet motor and the inductance Lq perpendicular to the permanent magnet. And Lq and φ, or Lq and Ld, as electrical constants of the permanent magnet motor adjusted by the constant adjuster.
[0006]
When the motor is a synchronous reluctance motor, the electric constant of the motor used in the current model magnetic flux calculator is an inductance Lγ in a direction in which the magnetic flux of the synchronous reluctance motor easily passes and an inductance Lδ in a direction perpendicular thereto. Let Lγ and Lδ be electrical constants of the synchronous reluctance motor adjusted by the constant adjuster.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An example block diagram in which the present invention is applied to a permanent magnet motor is shown in FIG. 1, and the present invention will be described in detail with reference to this figure. In the figure, the same numbers as those in FIG. 2 indicate the same blocks, and the description thereof is omitted.
[0008]
The current model magnetic flux calculator 10 is
φia = (Ld · id + φ) · cos (θ) −Lq · iq · sin (θ)
φib = (Ld · id + φ) · sin (θ) + Lq · iq · cos (θ)
・ ・ ・ ・ ・ ・ ・ ▲ 2 ▼
To calculate the primary flux linkage vector on the stationary coordinates. Here, φia and φib are components of the primary linkage magnetic flux vector φi.
id and iq are rotational coordinates converted from the output of the current detector 4 to the direction θ of the permanent magnet of the rotor of the permanent magnet motor 2 output from the speed position detector 3, and are the same as the output from the coordinate converter 5. .
[0009]
The timing generator 15 generates a pulse signal S having a predetermined cycle, and the voltage detector 11 detects or estimates the primary voltage of the permanent magnet motor 2, converts it into a vector, and outputs its components va and vb.
The voltage model magnetic flux fluctuation calculator 12
φv = ∫ (v−R · i) dt (3)
To calculate the primary flux linkage vector. Here, v is a primary voltage vector whose components are va and vb of the voltage detector 11 output, i is a primary current vector whose components are ia and ib of the current detector 4 output, and R is a permanent magnet motor. 2 is a primary winding resistance value.
The voltage model magnetic flux fluctuation calculator 12 receives the signal S output from the timing generator 15 and outputs φv in the equation (3) as Δφv when the pulse of the signal S is input. Clear the integrator to zero. That is, assuming that the time when the latest pulse is input is t1 and the time when the previous pulse is input is t0, the voltage model magnetic flux fluctuation calculator 12 has a permanent magnet motor between time t0 and t1. 2 is output as Δφv.
[0010]
The voltage model magnetic flux estimator 13 receives the signal S output from the timing generator 15 and when the pulse of the signal S is input,
φv1 = φi1 · Δφv / (φi1−φi0) (4)
To calculate and output the primary flux linkage vector. Here, Δφv is the output of the voltage model magnetic flux fluctuation calculator 12 when the pulse is input (time t1), and φi1 is the output of the current model magnetic flux calculator 10 when the pulse is input (time t1). Φi0 stores the output of the current model magnetic flux calculator 10 at the time when the previous pulse is input (time t0).
[0011]
The actual primary flux linkage vectors at time t0 and time t1 are φr0 and φr1, respectively, and the relationship between them and φi0 and φi1 is a constant vector A.
φi0 = A · φr0, φi1 = A · φr1
If it is expressed as follows, φv1 = φr1 · Δφv / Δφr by substituting it into the equation (4)
It becomes. Here, Δφr = φr1−φr0, and Δφr = Δφv unless there is an error in R in equation (3), so φv1 = φr1. That is, the output of the voltage model magnetic flux estimator 13 is an accurate primary flux linkage vector at time t1.
[0012]
The constant adjuster 14 receives the signal S output from the timing generator 15 and when the pulse of the signal S is input, φv1 of the voltage model magnetic flux estimator 13 output and the pulse are input (time t1). The q-axis inductance Lq used in the current model magnetic flux calculator 10 and the magnetic flux φ are adjusted so that the φi1 of the output of the current model magnetic flux calculator 10 in FIG. As a result, the values of Lq and (φ + Ld · id) are adjusted to be equal to the actual values.
[0013]
Since the output of the constant adjuster 14 is also input to the q-axis current command generator 9, the denominator of the calculation of equation (1) calculated by the q-axis current command generator 9 can be an accurate value. The permanent magnet motor 2 outputs torque according to the torque command Tr.
[0014]
The same effect can be obtained by using Ld instead of the constant φ adjusted by the constant adjuster 14.
[0015]
In the voltage model magnetic flux estimator 13, φv0 = φi0 · Δφv / (φi1−φi0) (5) instead of the equation (4).
May be used to output φv0, and the constant used in the current model magnetic flux calculator 10 may be adjusted so that φv0 and φi0 at time t0 stored in the constant adjuster 14 coincide with each other.
[0016]
When the motor is a synchronous reluctance motor, the current model magnetic flux calculator 10 obtains the primary flux linkage vector using the inductance Lγ in the direction in which the magnetic flux of the synchronous reluctance motor easily passes and the inductance Lδ in the direction perpendicular thereto. In the constant adjuster 14, Lγ and Lδ used in the current model magnetic flux calculator 10 can be adjusted to accurate values. When the torque control is performed using Lγ and Lδ, accurate torque control is possible because accurate Lγ and Lδ can be used.
[0017]
When the motor is an induction motor, the current model magnetic flux calculator 10 inputs the speed of the speed position detector 3 and the current vector of the current detector, and uses the mutual inductance M of the induction motor and the secondary time constant T2. The secondary linkage magnetic flux vector is calculated, and the voltage model magnetic flux fluctuation calculator 12 subtracts the voltage drop due to the primary winding resistance and the voltage drop due to the leakage inductance from the voltage vector v output from the voltage detector 11 as a time integration. Thus, the fluctuation of the secondary linkage magnetic flux vector is calculated, the voltage model magnetic flux estimator 13 obtains an accurate secondary linkage magnetic flux vector, and the constant adjuster 14 calculates the second output of the voltage model magnetic flux estimator 13. Induction current used in the current model flux calculator 10 so that the secondary linkage flux vector and the secondary linkage flux vector output from the current model flux calculator 10 match. It is possible to adjust the mutual inductance M and the secondary time constant T2 of the machine. And when it is the structure which performs torque control using M and T2, since exact M and T2 can be used, exact torque control is attained.
[0018]
【The invention's effect】
According to the present invention, it is possible to accurately grasp the constants of the electric motor that changes during operation. For example, it is possible to improve the accuracy of control using these constants as in torque control, which is practically useful. .
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to a permanent magnet motor.
FIG. 2 is a block diagram showing a torque control configuration of a permanent magnet motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Power converter 2 ... Permanent magnet motor 3 ... Speed position detector 4 ... Current detector 5 ... Coordinate converter 6 ... Inverse coordinate converter 7 ... Current control 8 ... d-axis current command generator 9 ... q-axis current command generator 10 ... current model magnetic flux calculator 11 ... voltage detector 12 ... voltage model magnetic flux fluctuation calculator 13 ..Voltage model magnetic flux estimator 14 ... constant adjuster 15 ... timing generator

Claims (3)

In the motor control device that controls the output torque and rotation speed of the motor to those command values,
A current detector that detects a primary current of the motor, converts the current into a vector, and outputs the vector;
A speed position detector for detecting a rotation speed or a rotation angle of the electric motor;
A current model magnetic flux calculator that inputs a primary current vector of the current detector output and a rotation speed or a rotation angle of the speed position detector output and calculates a primary flux linkage vector of the electric motor by an electrical constant;
A voltage detector that detects or estimates a primary voltage of the motor, converts the voltage into a vector, and outputs the vector;
A timing generator that outputs a pulse of a predetermined period, and among the two consecutive pulse outputs by this timing generator, the older one is time t0 and the newer one is time t1, and the primary voltage vector and the current of the voltage detector Using the primary current vector of the detector output and the primary winding resistance value of the motor, the fluctuation of the primary linkage flux vector of the motor between the times t0 and t1 is obtained by time integration with an initial value of zero. Voltage model magnetic flux fluctuation calculator to calculate,
The current model magnetic flux calculator output at time t0 is φi0, the current model magnetic flux calculator output at time t1 is φi1, and the output of the voltage model magnetic flux fluctuation calculator is Δφv at time t1. The primary flux linkage vector φv1 of
φv1 = Δφv · φi1 / (φi1-φi0)
A voltage model magnetic flux estimator to be calculated by
A constant adjuster for adjusting an electric constant of the electric motor used in the current model magnetic flux calculator so that φv1 of the voltage model magnetic flux estimator and φi1 of the current model magnetic flux calculator output coincide with each other; An electric motor control device characterized by that. In the case where the motor is a permanent magnet motor, the electric constant of the motor used in the current model magnetic flux calculator is a magnetic flux amount φ of the permanent magnet of the permanent magnet motor, and an inductance Lq in a direction perpendicular to the permanent magnet. 2. The motor control device according to claim 1, wherein an inductance Ld is used, and the Lq and φ or the Lq and Ld are set as the electrical constant of the permanent magnet motor adjusted by the constant adjuster. When the motor is a synchronous reluctance motor, the electric constant of the motor used in the current model magnetic flux calculator is an inductance Lγ in a direction in which the magnetic flux of the synchronous reluctance motor easily passes and an inductance Lδ in a direction perpendicular thereto, 2. The motor control device according to claim 1, wherein the Lγ and Lδ are set as electrical constants of the synchronous reluctance motor adjusted by a constant adjuster.

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