JPH11146700A - Control method of synchronous motor - Google Patents

Abstract

(57) [Problem] To solve the difference between the magnetic flux calculated by the magnetic flux calculation and the actual magnetic flux due to a decrease in the value of the armature reaction reactance of the synchronous motor when the magnetic flux increases due to the magnetic saturation phenomenon. Find the magnetic saturation model of the synchronous motor. SOLUTION: The magnetic saturation characteristic X _ad ( _id , 0) = X _ad of a linear-axis armature reaction reactance, which is the only measured value of a magnetic saturation model as a no-load saturation characteristic in a synchronous motor.
(I _f, 0) and the resulting (S _1), sine component A _d of the fundamental wave of the magnetic vector potential in combination with the direct axis armature current i _d and the horizontal axis armature current _{i q (i d, i q} ) , The cosine component A _q
(I _d, i _q) the calculated (S _2), further unsaturated value X _aq (0,0) to obtain the horizontal axis armature reaction reactance (S _3),
By combining this measured value and the magnetic field analysis value (S ₄ ), the saturation characteristic of the horizontal axis armature reaction reactance is determined (S ₆ ).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic saturation model of a synchronous motor used for magnetic flux calculation for vector control, which is an operation that cannot be measured by a finite element method magnetic field analysis using a no-load saturation characteristic which is a measured value. The present invention relates to a synchronous motor control method using a high-accuracy magnetic saturation model by compensating magnetic saturation characteristics under a state.

[0002]

2. Description of the Related Art FIG. 5 is also used in the present invention,
FIG. 2 is a block diagram showing a basic configuration of a drive control device of a general synchronous motor that has been used in the related art, wherein 1 is a drive control device that supplies electric power based on a speed command value N, and 2 is a drive control device. 3 shows a synchronous motor as an object.
The drive control device 1 includes a speed controller 11, a magnetic flux controller 12, a current controller 13, a coordinate converter 14, a power supply 15, a rotational speed n of the rotor of the synchronous motor 2, and a speed / position for detecting the position of the magnetic pole. A detector 16 and a magnetic flux calculator 17 are provided.

The speed controller 11 compares a speed command value N given from the outside with the rotation speed n of the rotor of the synchronous motor 2 detected by the speed / position detector 16, and based on the comparison result, determines the torque current. The command value is calculated and output to the current controller 13. The magnetic flux controller 12 is a synchronous motor 2
Is calculated from the magnetic flux reference value input from the magnetic flux reference value setting unit 19, in other words, the excitation current command value required to match the magnetic flux command value, and outputs this to the current controller 13. . Since the magnitude of the magnetic flux inside the synchronous motor 2 cannot be directly measured, the magnitude of the magnetic flux calculated by the magnetic flux calculator 17 is used.

The current controller 13 determines a torque current command value input from the speed controller 11 and an exciting current command value input from the magnetic flux controller 12 and a magnetomotive force input from the coordinate converter 18 to determine the direction of magnetic flux. The orthogonal torque current and the exciting current whose magnetomotive force is in the direction of the magnetic flux are compared, a current control signal is calculated from the comparison result, and this is output to the coordinate converter 14. The coordinate converter 14 converts the current control signal input based on the direction of the magnetic flux calculated by the magnetic flux calculator 17 into a control signal of three-phase AC and field current, and outputs this to the power supply 15. . The power supply 15 is composed of an inverter or the like, and supplies the synchronous motor 2 with a three-phase alternating current and a field current corresponding to a control signal input from the coordinate converter 14.

A speed / position detector 16 detects a rotation speed n and a position of a magnetic pole by a rotation speed detector provided on a rotor of the synchronous motor 2, and determines the rotation speed n by a speed controller 11 and a magnetic flux reference value setting device. 19, and the position of the magnetic pole is
8 is output. The magnetic flux reference value setting unit 19 determines a magnetic flux having a magnitude corresponding to the input rotation speed n of the rotor, and outputs this to the magnetic flux controller 12. The coordinate converter 18 is connected to the power supply line from the power supply 15 to the synchronous motor 2 for each position of the magnetic pole of the rotor detected by the speed / position detector 16 based on the direction of the magnetic flux calculated by the magnetic flux calculator 17. U phase, w detected by the provided current detectors SE _u , SE _W and SE _f
The respective currents i _u , i _W , and i _f of the phase and the field are coordinate-transformed into torque currents whose magnetomotive force is orthogonal to the direction of the magnetic flux and exciting currents whose magnetomotive force is in the direction of the magnetic flux. Output. As the direction of the magnetic flux, a value calculated by the magnetic flux calculator 17 is used. 6 and 7 previously input to the magnetic flux calculator 17
The direction and magnitude of the magnetic flux are calculated based on the characteristic data as shown in FIG. 2, that is, the magnetic saturation model of the synchronous motor, and are output to the coordinate converters 14, 18 and the magnetic flux controller 12.

FIG. 6 is a characteristic diagram showing a saturation characteristic of the magnetic flux φ with respect to the exciting current i ₀ , and the horizontal axis represents the exciting current i ₀ and the vertical axis represents the magnetic flux φ. FIG. 7 shows the magnetic flux φ ₀ , φ
FIG. 9 is a characteristic diagram showing saturation characteristics (magnetic saturation model) of the armature reaction reactance obtained by dividing _s by the exciting current i ₀ with respect to the exciting current i ₀ , and the horizontal axis represents the exciting current i ₀ , and the vertical axis represents the motor current. The child reaction reactance φ / i ₀ is shown.

Since the synchronous motor 2 generates a torque corresponding to the product of the torque current and the magnitude of the magnetic flux, it is necessary to accurately set and control the magnitude of the torque current and the magnitude of the magnetic flux. If the accuracy of the torque current coordinate-converted based on the direction of the magnetic flux calculated by the magnetic flux calculator 17 and the accuracy of the magnitude of the magnetic flux calculated by the magnetic flux calculator 17 are poor, accurate torque control becomes difficult. Therefore, it is important for accurate torque control to match the direction and magnitude of the magnetic flux calculated by the magnetic flux calculator 17 with that of the actual magnetic flux inside the synchronous motor 2.

[0008]

The magnetic saturation model shown in FIG. 7 is obtained from the characteristic diagram showing the no-load saturation characteristic shown in FIG. The no-load saturation characteristic is obtained by measuring an armature voltage due to a direct-axis magnetic flux generated by flowing only a field current under no-load conditions in which no armature current flows. That is, the magnetic saturation model shown in FIG. 7 expresses the magnetic saturation characteristics of the magnetic flux of the direct axis due to the magnetomotive force of the direct axis, which is the direction of the magnetic pole of the synchronous motor 2. FIG. 9 is a conceptual diagram showing the magnetic flux of the pole piece of the armature in the synchronous motor 2 under the no-load operation condition.

On the other hand, under a load condition in which an armature current flows,
There is a direct magnetic flux in the magnetic pole direction due to the direct axis armature current shown in FIG. 10, and a horizontal magnetic flux perpendicular to the magnetic pole due to the horizontal axis armature current shown in FIG. FIG. 12 is a diagram showing FIG.
FIG. 11 is a conceptual diagram showing a magnetic flux under a load condition in which a magnetic flux shown in FIG. 10, a direct-axis magnetic flux shown in FIG. 10 based on a direct-axis armature current, and a horizontal-axis magnetic flux shown in FIG.

Under the load condition where the magnetic flux becomes a complicated flow,
If the magnetic saturation model shown in FIG. 7 obtained based only on the magnetic flux shown in FIG. 9 is used, the magnetic flux of the synchronous motor 2 cannot be represented accurately, and as a result, the magnetic flux calculator 1 of the drive control device 1
The magnitude and direction of the magnetic flux calculated in step 7 do not match the actual magnitude and direction of the magnetic flux of the synchronous motor 2 to be controlled.

If there is a large difference between the magnetic saturation characteristics under the load condition and the magnetic saturation characteristics under the no-load condition, the torque control accuracy and control stability will deteriorate, and the operating range will be reduced. Limiting or increasing the size of the synchronous motor 2 so as not to cause a large difference between the magnetic saturation characteristics under the load condition and the magnetic saturation characteristics under the no-load condition, in other words, manufacturing an expensive synchronous motor There was a problem that had to be.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has expanded a control limit enabling stable control, and has improved magnetic saturation characteristics under a load condition and a no-load condition. It is an object of the present invention to provide a magnetic saturation model of a synchronous motor that enables vector control of a synchronous motor having good control stability even in an inexpensive synchronous motor having a small size and a large difference.

[0013]

According to a first aspect of the present invention, there is provided a synchronous motor control method for measuring a saturation characteristic of a linear shaft armature reaction reactance under no-load operation conditions obtained from a no-load saturation characteristic test. The values are combined with the magnetic field analysis values of the saturation characteristics obtained by the finite element method as a function of the currents on the direct and horizontal axes, and the direct-axis armature reaction reactance and the horizontal-axis armature reaction reactance are respectively plotted on the direct and horizontal axes. A magnetic saturation model of the synchronous motor determined as a function of the current of the motor.

According to a second aspect of the present invention, there is provided the synchronous motor control method, wherein the horizontal axis armature reaction reactance for obtaining the magnetic flux is corrected in proportion to the sum of the absolute values of the field current and the direct axis armature current. It is characterized in that a value obtained by subtracting the amount is used.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. (Embodiment 1) In Embodiment 1 of the present invention, FIG.
The conventional synchronous motor drive control device shown in FIG.
7 except for the magnetic saturation model of the synchronous motor used in FIG. FIG. 5 shows a drive control device 1 that supplies electric power based on a speed command value N and a synchronous motor 2 that is a drive control target in a control device that implements the synchronous motor control method according to the present invention. The drive control device 1 includes a speed controller 11, a magnetic flux controller 12, a current controller 13, a coordinate converter 14, a power supply 15, a rotational speed n of the rotor of the synchronous motor 2, and a speed / position for detecting the position of the magnetic pole. Detector 16
And a magnetic flux calculator 17.

The speed controller 11 compares a speed command value N given from the outside with the rotation speed n of the rotor of the synchronous motor 2 detected by the speed / position detector 16, and based on the comparison result, determines the torque current. The command value is calculated and output to the current controller 13. The magnetic flux controller 12 is a synchronous motor 2
Is calculated from the magnetic flux reference value input from the magnetic flux reference value setting unit 19, in other words, the excitation current command value required to match the magnetic flux command value, and outputs this to the current controller 13. . Since the magnitude of the magnetic flux inside the synchronous motor 2 cannot be directly measured, the magnitude of the magnetic flux calculated by the magnetic flux calculator 17 is used. The current controller 13 is the speed controller 1
Command value and magnetic flux controller 12 input from 1
Is compared with an exciting current command value inputted from the coordinate converter 18 and a torque current whose magnetomotive force is orthogonal to the direction of magnetic flux and an exciting current whose magnetomotive force is in the direction of magnetic flux. The control signal is calculated and output to the coordinate converter 14. The coordinate converter 14 converts the current control signal input based on the direction of the magnetic flux calculated by the magnetic flux calculator 17 into a control signal of three-phase AC and field current, and outputs this to the power supply 15. . The power supply 15 is composed of an inverter or the like, and supplies the synchronous motor 2 with a three-phase alternating current and a field current corresponding to a control signal input from the coordinate converter 14.

A speed / position detector 16 detects a rotation speed n and a position of a magnetic pole by a rotation speed detector provided on a rotor of the synchronous motor 2, and determines the rotation speed n by a speed controller 11 and a magnetic flux reference value setting device. 19, and the position of the magnetic pole is
8 is output. The magnetic flux reference value setting unit 19 determines a magnetic flux having a magnitude corresponding to the input rotation speed n of the rotor, and outputs this to the magnetic flux controller 12.

The coordinate converter 18 converts the power from the power supply 15 to the synchronous motor 2 for each position of the rotor magnetic pole detected by the speed / position detector 16 based on the direction of the magnetic flux calculated by the magnetic flux calculator 17. Current detectors SE _u and S provided on the feeder line
E _W u phase detected by and SE _f, the current i _u and w phase and magnetic field, i _W, the torque current and magnetomotive force its magnetomotive force a i _f is orthogonal to the direction of the magnetic flux in the direction of the magnetic flux The coordinates are converted into an exciting current, and these are output to the current controller 13. As the direction of the magnetic flux, a value calculated by the magnetic flux calculator 17 is used. The magnetic flux calculator 17 calculates the direction and magnitude of the magnetic flux based on a new magnetic saturation model of the synchronous motor as described below, and outputs this to the coordinate converters 14 and 18 and the magnetic flux controller 12.

Hereinafter, the process of deriving the magnetic saturation model of the synchronous motor used in the present invention will be described with reference to the explanatory diagram shown in FIG. FIG. 1 is an explanatory diagram showing a process of deriving a magnetic saturation model of a synchronous motor according to the present invention. The no-load saturation characteristic is the only possible measured value for the magnetic saturation model, and is analyzed by a finite element method magnetic field analysis. A magnetic saturation model that compensates for the magnetic saturation characteristics in an operation region where measurement is practically impossible and that can accurately express the magnetic saturation characteristics of the synchronous motor not only under no-load conditions but also under load conditions is obtained.

(A) In FIG. 1, S₁Is the no-load saturation characteristic
Magnetic Saturation Characteristics of Direct-axis Armature Reaction Reactance from Test
Function X representing_ad(I_d, 0). No load
In the sum characteristics test, the reciprocation of the
The magnetic saturation characteristics of the reactance are measured. This magnet
When the saturation characteristics are expressed by the unit method, the voltage shown in FIG.
The value is almost the same as the magnetic flux shown, and as shown in FIG.
Armature reaction reactor by dividing
Is found. That is, the field current i _fShaft electric machine by excitation of
Child reaction reactance X_adExpressing the magnetic saturation characteristics of
Number X_ad (i_f) Is obtained. The field shown in FIG.
The magnetic flux when only the magnetic current flows is compared with the magnetic flux shown in FIG.
The direct-axis magnetic flux when only the shaft armature current flows is the N pole
Since they can be considered almost equal except that the S pole is opposite,
Field current i_f-Axis armature reaction reactor when flowing only
Function X representing saturation characteristics_ad (i_f) And
Armature current i_d-Axis armature reaction rear when only flowing
Function X representing the saturation characteristic of the reactance_ad (i_d) Is a unit
It is almost the same when expressed by the law. Function representing this saturation characteristic
Is the horizontal axis armature current i_qX so that the effects of_ad (i
_d, I_q) Like i_dAnd i_qFunction expression of two variables
Then, the horizontal axis armature current i_q= 0 armature anti-axis armature condition
Action reactance X_ad (i_d, i_q), Ie, X _ad
 (i_d, 0) = X_ad (i_f, 0) is obtained as the measured value.
You.

[0021] (b) the magnetic vector potential of the armature inner diameter S ₂ is determined by magnetic field analysis in FIG. 1 A _d (i _d,
iq ) and _Aq ( _id , _iq ).

The direct axis armature current _id and the horizontal axis armature current _iq
The magnetic field analysis by the finite element method is performed with the combination of. FIG. 2 is a magnetic field analysis diagram in which an electric angle is set to 0 degree on the direct axis and an area of one pole from 0 to 180 degrees is performed under a periodic boundary condition.
Assuming that the magnetic flux density is B, the magnetic vector potential is A, the magnetic permeability is μ, and the current density is J, the basic equation of the magnetic field analysis is expressed by equation (1).

[0023]

(Equation 1)

The straight axis armature current _id and the horizontal axis armature current _iq
From the results of the magnetic field analysis performed in combination with the above, the Fourier expansion is performed on the magnetic vector potential A along the inner diameter of the armature of the synchronous motor. The fundamental wave of a sine (sin) component of the magnetic vector potential of Fourier expansion in the range of electrical angle 0 ° 180 ° _{A d (i d, i q} ), cosine (co
Assuming that the s) component is A _q ( _id , _iq ), the magnetic flux direct axis component φ _ad ( _id , _iq ) and the magnetic flux horizontal axis component φ _aq ( _id , i
_q ) and a proportional relationship such as equation (2) holds.

[0025]

(Equation 2)

[0026] The foregoing as abscissa armature current i direct-axis armature reaction reactance at the conditions of _{q = 0 X ad (i d} , i q)
Magnetic saturation characteristic, i.e. X _ad (i _d, 0) are obtained as the measured value, the combination of magnetic field analysis value by the following equation to the measured values in the no-load condition at S ₄ as shown in FIG. 1 , the function X _ad showing the saturation characteristic of the direct-axis armature reaction reactance is a function of the direct-axis armature current i _d and the horizontal axis armature current i _q
( _Id , _iq ) can be obtained by the following equation (3).

[0027]

(Equation 3)

(C) S in FIG._ThreeIs the horizontal axis armature
Value of reactance X_aqProcess for finding (0,0)
It is a block showing. Horizontal axis armature reaction reactance
X_aqIt is difficult to actually measure the saturation characteristics of. There
Shaft armature current i_dAnd the horizontal axis armature current i_qIs extremely small
Condition (i_d≒ i_q不 0) the unsaturated value, ie X_aq(0,
FIG. 1 shows that only one point of 0) can be measured.
S as shown_FourCombine this measured value with the magnetic field analysis value
And the direct-axis armature current i_dAnd the horizontal axis armature current i_qFunction and
Represents the saturation characteristics of the abscissa armature reaction reactance
Function X_aq(I_d, I _q) Is obtained as equation (4). In addition,
I used in equation (4)_q0Is i_qUsed in place of = 0
With a small horizontal armature current that does not cause magnetic saturation
is there.

[0029]

(Equation 4)

(D) In FIG. 1, S ₅ is a magnetic saturation model of the linear axis armature reaction reactance in which the results of equation (3) are shown in table form, and specific numerical values are shown in Table 1. In this magnetic saturation model, the direct-axis armature current i _d = direct-axis armature reaction reactance measured value of 7 points for 0 to 1.5 X _ad
Using a (i _d, 0), the horizontal axis armature current i _q = magnetic field analysis result of performing at 7 × 6 = 42 points a combination of six points for _{0~1.5 A d (i d, i} q) with Is a magnetic saturation model of the direct-axis armature reaction reactance determined by the unit method. The magnetic saturation model composed of these 42 points is input to the magnetic flux calculator 17 of the drive control device 1 shown in FIG.
Flux calculator 17 creates an interpolation equation from the value of 42 points is input, the field current i _f and the direct-axis armature current i Synthesis of _d direct axis current i _f + i _d, the horizontal axis armature current i _q X _ad ( _if + _id , _iq ) is obtained for an arbitrary combination of the above and the calculation of the magnetic flux is performed.

[0031]

[Table 1]

(E) In FIG. 1, S ₆ is a magnetic saturation model of the abscissa armature reaction reactance in which the results of equation (4) are shown in table form, and the specific numerical values are shown in Table 2. In this magnetic saturation model, one point of the measured unsaturated value X _aq ( _0,0 ) of the horizontal-axis armature reaction reactance and the direct-axis armature current i
7 points for _d = 0 to 1.5, the horizontal axis armature current i _q = 0
Combining 6 points for ~1.5, 7 × 6 = 42 magnetic field analysis result of performing at point _{A q (i d, i q} ) with unit normal magnetic saturation model of horizontal axis armature reaction reactance determined using It is an expression. The magnetic saturation model composed of these 42 points is used to calculate the magnetic flux calculator 17 of the drive control device 1 shown in FIG.
Enter Flux calculator 17 creates an interpolation equation from the value of 42 points is input, the field current i _f and the direct-axis armature current i _d
Combined axis-axis armature current _if + _id , horizontal-axis armature current _iq
X _aq ( _if + _id , _iq ) for any combination of
And calculate the magnetic flux. The magnetic saturation models shown in Tables 1 and 2 obtained in this way are set in the magnetic calculator 17 shown in FIG. 5, and drive control based on vector control for the synchronous motor 2 is performed.

[0033]

[Table 2]

Next, the operation will be described. FIG.
In the drive control device 1 for the starting motor, the coordinate converter 18 detects the current.
Dispenser SE _u, SE_W, SE_fCurrent i detected from_u,
i_W, I_fIs the direction of the magnetic flux input from the magnetic flux calculator 17.
The magnetomotive force is orthogonal to the direction of the magnetic flux based on the direction and size
Coordinates the torque current and the exciting current whose magnetomotive force is in the direction of the magnetic flux.
The current is converted and output to the current controller 13. This coordinate transformation is
Physically, it is performed in the following two stages. That is, first of all,
Armature current i_u, I_WBy the conversion formula shown in the following equation (5)
Direct-axis armature current i_dAnd the horizontal axis armature current i_qIs converted to
You. Θ in the equation (5) is the u-phase winding of the armature of the synchronous motor 2.
The electrical angle between the direction of the magnetomotive force and the direction of the magnetomotive force of the field winding.
And the speed / position detector 16 detects it.

[0035]

(Equation 5)

Next, the torque current and the magnetomotive force whose magnetomotive force is orthogonal to the direction of the magnetic flux are coordinate-converted into the exciting current in the magnetic flux direction. The direction of the magnetic flux used as the reference for coordinate transformation is the magnetic flux calculator 1
7 is calculated as follows. For example, the field current i
_f = 1.4, direct-axis armature current i _d = -0.6, if the horizontal axis armature current i _q = 0.7, the synthesis direct axis of the field current i _f and the direct-axis armature current i _d current i _f + i _d = 1.4-0.6
= 0.8, and the because the horizontal axis armature current i _q = 0.7, referring to magnetic saturation model of the direct-axis armature reaction reactance shown in Table 1, X _ad (0.8,0.7 ) = 1.
018 is obtained. Similarly, referring to the magnetic saturation model of the horizontal axis armature reaction reactance shown in Table 2, X _aq (0.
8, 0.7) = 0.610. In other words, under the load condition as well as the no-load condition, the direct-axis armature reaction reactance X _ad and the horizontal-axis armature reaction reactance X _aq are obtained for any combination of the field current and the armature current. X _ad and X _aq indicate the directions of the armature flux linkage φ _d , the armature flux linkage _{q q} and the armature flux linkage on the horizontal axis from the armature leakage reactance X ₁ obtained separately. The electrical angle θ _s is given by the following equation (6).

[0037]

(Equation 6)

The magnetic flux controller 12 adjusts the magnitude of the armature interlinkage magnetic flux of the synchronous motor 2 to the magnetic flux command value determined by the magnetic flux reference value setting device 19 according to the speed detected by the speed / position detector 16. Control is performed so that they match. Since the magnitude of the magnetic flux inside the synchronous motor cannot be directly measured, the magnitude φ of the magnetic flux calculated by the magnetic flux calculator 17 is used.
The magnitude φ of this magnetic flux is the above-mentioned direct-axis armature linkage flux φ _d
And the horizontal axis armature interlinkage magnetic flux φ _q is given by the following equation (7).

[0039]

(Equation 7)

The current controller 13 calculates a control signal as a torque current whose magnetomotive force is orthogonal to the direction of magnetic flux and an exciting current whose magnetomotive force is in the direction of magnetic flux. The control signal is
The electric current is converted into a three-phase alternating current and a field current by the coordinate converter 14 and supplied to the synchronous motor 2 through the power supply 15. Also in this coordinate conversion, the direction of the magnetic flux calculated by the magnetic flux calculator 17 is used as a reference.

In the first embodiment, the direction and magnitude of the magnetic flux can be calculated for any combination of the field current and the armature current under the load condition as well as the no-load condition. Flux calculator 1 under conditions
The direction and magnitude of the magnetic flux calculated in step 7 can be made to match the actual magnetic flux of the synchronous motor 2, and there is an effect that accurate torque control becomes possible.

[0042] When the load (Embodiment 2) synchronous motor 2 becomes extremely large, positive field current i _f and the negative direct axis armature current i _d both become very large value, the magnetic flux due to the field current i _f flux by the direct-axis armature current i _d is a state of canceling little. In such a state, as shown in FIG. 3, the field winding leakage flux remaining as a residual of the canceled magnetic flux and the horizontal axis flux are superimposed, and local magnetic saturation occurs at the end of the pole piece. There is. When this local magnetic saturation occurs, instead of the horizontal axis armature reaction reactance X _aq of Table 2 described in the first embodiment, a value obtained by correcting the value to a small value as shown in FIG. 4 is used. Improve the accuracy of magnetic flux calculation.

FIG. 4 shows a magnetic saturation model according to the second embodiment.
FIG. 7 is an explanatory diagram showing a derivation process of
And the positive field current i_fAnd the negative straight-axis armature current i_dRespectively
Is very large, and the combined current i on the direct axis is_f+ I_dTo
Comparison i_f−i_dIs large, so i_f−i_dA supplement focused on
Do positive. That is, S in FIG.₁₁Horizontal electric motor as shown
Child reaction reactance X_aqAs positive field current i_fWhen
Negative direct axis armature current i _dA complement proportional to the sum of the respective absolute values
Positive amount K (i_f−i_d) To reduce that value
Horizontal axis armature reaction reactance X_aqIs used. Field
Current i_f, The direct-axis armature current i_d, The horizontal axis armature current i_qof
Complement of the horizontal axis armature reaction reactance as a function of three variables
X for positive result_aq(I_f, I_d, I_q), As shown in FIG.
Axis composite current i_f+ I_dAnd the horizontal axis armature current i_qOf two variables
Horizontal axis armature reaction reactance X before correction, which is a function_aq
(I_f+ I_d, I_q), The proportional coefficient is k, and the positive field current i
_fAnd the negative straight-axis armature current i_dI is the sum of the absolute values of_f−
i_dThen, this magnetic saturation model is expressed by the following equation (8).
Is done.

[0044]

(Equation 8)

For example, the field current i_f= 2.1, direct shaft electric
Child current i_d= -1.9, horizontal armature current i_q= 0.5
The field current i_fAnd direct-axis armature current i_dThe composite straight-axis
The flow is i_f+ I_d= 2.1-1.9 = 0.2, current on the horizontal axis
Is i_q= 0.5, so the horizontal axis armature counteraction shown in Table 2
Reactance X_aqReferring to the magnetic saturation model of _aq
(0.2, 0.5) = 0.700 is obtained. So far
The processing is the same as in the first embodiment. In the second embodiment,
Further, a proportional coefficient k = 0.035, a positive field current and a negative direct axis
Sum i of the absolute values of each armature current_f−i_d= 2.1 + 1.
9 = 4.0, from which 0.56 = 0.700-0.0
35 × 4.0 and horizontal axis armature reaction reactance X_aqThe value of the
From 0.70 to 0.56. Used here
The value of the proportional coefficient k is i_f, I_d, I_qIndividually given
It can be found from magnetic field analysis. In addition, adjustment operation
It is also possible to find an optimal value.

As described above, in the second embodiment, in which the correction of the horizontal axis armature reaction reactance is added to the first embodiment, not only under no-load conditions and normal load conditions, but also under an extremely large load condition, Since the direction and magnitude of the magnetic flux can be calculated for the combination of the field current and the armature current, the range in which the magnetic flux calculated by the magnetic flux calculator 17 matches the actual magnetic flux of the synchronous motor 2 is described in the embodiment. There is an effect that the operating range in which accurate torque control is possible can be expanded as compared with the case of only one.

[0047]

As described above, according to the first aspect of the present invention, the measured value of the linear axis armature reaction reactance saturation characteristic under the no-load operation condition obtained from the test result of the no-load saturation characteristic, and the linear axis The linear axis armature reaction reactance and the horizontal axis armature reaction reactance are combined with the magnetic field analysis value of the saturation characteristic calculated by the finite element method from the current function on the horizontal axis and the current on the horizontal axis. Even if the magnetic saturation characteristics under load conditions differ from the magnetic saturation characteristics under no-load conditions, the magnetic flux calculated by the magnetic flux calculator must match the actual magnetic flux of the synchronous motor even if the magnetic saturation characteristics under load conditions differ from the magnetic saturation models of synchronous motors. The control stability can be improved, the control limit can be expanded, and the size of the synchronous motor can be increased. The constant can be an effect which can be used a small inexpensive synchronous motor physique.

According to the second aspect of the present invention, the horizontal axis armature reaction reactance according to the first aspect is obtained by subtracting a correction amount proportional to the sum of the absolute values of the field current and the direct axis armature current. Since the value of the abscissa armature reaction reactance with a smaller value is used, even under extremely large load conditions, the magnetic flux calculated by the magnetic flux calculator and the magnetic flux of the actual synchronous motor can be matched. The control stability can be improved and the control limit can be expanded as compared with the case where only the invention described in Item 1 is applied. In addition, since the magnetic flux can be calculated with high accuracy even when a complicated magnetic saturation phenomenon appears by manufacturing the synchronous motor with a small size, an inexpensive synchronous motor having a small size compared to the case where only the invention according to claim 1 is applied. There is an effect that can be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a process of deriving a magnetic saturation model of a synchronous motor according to a first embodiment of the present invention.

FIG. 2 is a magnetic flux diagram showing magnetic vector potential contours as a result of a magnetic field analysis by a finite element method performed on a combination of a direct axis armature current and a horizontal axis armature current.

FIG. 3 is a conceptual diagram showing a field winding leakage flux and a horizontal axis flux that interfere at an end of a pole piece and are considered in a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a process of deriving a magnetic saturation model of a synchronous motor according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a drive control device for a synchronous motor by vector control.

FIG. 6 is a characteristic diagram showing a conventional magnetic saturation characteristic (magnetic saturation model).

FIG. 7 is a characteristic diagram showing a conventional magnetic saturation characteristic (magnetic saturation model).

FIG. 8 is a characteristic diagram showing a no-load saturation characteristic.

FIG. 9 is a conceptual diagram showing a direct-axis magnetic flux generated under a no-load condition in which only a field current flows.

FIG. 10 is a conceptual diagram showing a direct-axis magnetic flux when only a direct-axis armature current flows.

FIG. 11 is a conceptual diagram showing a horizontal axis magnetic flux when only a horizontal axis armature current flows.

FIG. 12 is a conceptual diagram showing magnetic flux when a direct-axis magnetic flux and a horizontal-axis magnetic flux are mixed under a load condition.

[Explanation of symbols]

1 drive control device, 2 synchronous motor, 11 speed controller, 12 flux controller, 13 current controller, 14 coordinate converter, 15 power supply, 16 speed / position detector,
17 flux calculator, 18 coordinate converter, 19 magnetic flux reference value _{setter, SE u, SE W, SE} f current detector.

Claims (2)

[Claims] 1. A finite element method as a function of a measured value of a saturation characteristic of a linear axis armature reaction reactance under a no-load operating condition obtained from a no-load saturation characteristic test and a current of a linear axis and a horizontal axis. And a magnetic saturation model of a synchronous motor in which the linear-axis armature reaction reactance and the horizontal-axis armature reaction reactance are determined as a function of the currents on the linear and horizontal axes, respectively. To control a synchronous motor. 2. As a horizontal axis armature reaction reactance,
2. The synchronous motor control method according to claim 1, wherein a value obtained by subtracting a correction amount proportional to a sum of absolute values of the field current and the direct-axis armature current is used.