JP4043741B2 - Electric motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electric motor that uses only reluctance torque used in a machine tool or the like, or uses reluctance torque and magnet torque, and more particularly, to a field current control method.
[0002]
[Prior art]
FIG. 10 shows a block diagram of a motor control device applied for feed axis control and spindle control of a general machine tool. For convenience of explanation, a host controller that generates a torque command value, a phase distribution of a field (hereinafter referred to as d-axis) current command value and an armature (hereinafter referred to as q-axis) current command value according to the rotor position. The phase distribution unit, the vector calculation unit, and the power conversion unit are omitted.
A q-axis current calculation unit 1 and a d-axis current calculation unit 2 are provided to calculate a q-axis current command value SIQC and a d-axis current command value SIDC, respectively.
The q-axis current calculation unit 1 includes a torque command limiting unit 13 and a torque / q-axis current conversion unit 14, and a torque command value STC is given to the torque command limiting unit 13 from the host controller, depending on the rotor speed SPD. The torque command limit value is calculated, the torque command value STC is compared with the torque command limit value, and clamp processing is performed below the limit value, whereby the corrected torque command value STCC is output.
The corrected torque command value STCC is dimension-converted by the torque / q-axis current converter 14 and a q-axis current command value SIQC is output.
The d-axis current calculation unit 2 includes a magnetic flux command generation unit 91, a magnetic flux reduction rate calculation unit 6, and a magnetic flux / d-axis current conversion unit 12. The magnetic flux command generation unit 91 generates a magnetic flux command value SID that is normally a fixed value. The magnetic flux reduction rate calculation unit 6 calculates a magnetic flux reduction coefficient SKID with reference to the rotor speed SPD, and multiplies the magnetic flux command value SID to obtain a magnetic flux command value SIDC0.
The magnetic flux command SIDC0 is dimension-converted by the magnetic flux / d-axis current command converter 12 to output a d-axis current command value SIDC.
[0003]
[Problems to be solved by the invention]
In general, a reluctance type motor (RM) or a permanent magnet internal type motor (IPM) that uses reluctance torque and magnet torque has a d-axis current corresponding to the field of a permanent magnet of a general permanent magnet type motor on the principle of operation. Control is needed.
In particular, when used for high-speed rotation applications of several thousand revolutions or more, a saturation phenomenon occurs with respect to the power supply voltage unless the field in the rotor is weakened by control of the d-axis current, There is a problem that both the phase and the followability are poor, a desired torque cannot be obtained, and stable control cannot be performed.
[0004]
In addition, due to the rotor structure described later in the above motor, torque is not generated when the applied current is small, or when the applied current changes little, a torque insensitive region occurs, and control response As a result, the acceleration / deceleration time is prolonged and the torque ripple becomes large in the boundary region between the dead region and the steady region, resulting in the occurrence of rotation unevenness.
As is well known, the principle of generating the reluctance force is based on the magnetoresistance difference (inductance difference) between the d axis and the q axis in the rotor.
For this reason, in order to provide a magnetoresistive difference, it is necessary to devise a method of providing a slit-like gap in the rotor or sandwiching a non-magnetic material. There is also a disadvantage that it becomes weaker. Therefore, in order to increase the rotor strength, a mechanical bridging portion is provided by providing a mechanical bridging portion outside the rotor or in a slit-like gap, but at the same time, a magnetic bridging portion is also formed.
Even if the rotor structure is devised so as to prevent a magnetic short circuit due to the bridging part, the entire rotor is molded, or external reinforcement with an annular non-magnetic material is performed between the stator and the rotor. There is always a gap, and in the type of motor that obtains torque using the magnetoresistive difference, the loss at the time of magnetic energy transfer of the magnetic bridge part at the outer periphery of the rotor and the gap between the stator and the rotor is always Will exist.
In addition, the H-B (magnetizing force-magnetic flux density) characteristics of the soft magnetic material forming the magnetic path have a large rate of change of the magnetic flux density with respect to the current change in a region where the current is small (= H is small), and the stable magnetic flux. There is a property that cannot be obtained.
Due to the above factors, a torque dead zone exists and a problem arises that stable control cannot be performed.
[0005]
The present invention has been made in view of the above circumstances, and provides an electric motor control device that can perform stable control while avoiding voltage instability, instability of control due to the rotor structure and the magnetic characteristics of the soft magnetic material. The purpose is to do.
[0006]
[Means for Solving the Problems]
In the present invention, there is provided a control unit for an electric motor comprising a rotor having an inductance change when viewed from the stator winding in the direction of rotation has a soft magnetic material, a speed detecting means for detecting a rotor speed, the upper position and the q-axis current calculating unit for calculating a q-axis current command value from the torque command value commanded from the controller, and the d-axis current calculating portion d-axis current command value is calculated according to the rotor speed, the electric motor and a current detection means for detecting a d-axis current and a q-axis current , wherein the d-axis current calculation unit calculates a magnetic flux command value by referring to the q-axis current command value. comprising a part, and a voltage estimator for estimating the inter-terminal voltage value of the motor with reference to the d-axis current detection value and a q-axis current detection value by the current detecting means and the rotor speed, the terminal voltage value calculating a voltage bias value from the magnetic The command value corrected by the voltage bias value calculates the d-axis current command value.
[0007]
In the present invention, the d-axis current calculation unit further corrects the magnetic flux reduction coefficient calculated with reference to the rotor speed by the voltage bias value , and the magnetic flux command value is corrected by the corrected magnetic flux reduction coefficient. And the d-axis current command value is calculated.
[0008]
In the present invention, a q-axis current is obtained from a torque command value commanded by a host controller for an electric motor having a rotor having a soft magnetic material and having an inductance change as viewed from the stator winding in the rotation direction. In a motor control device comprising: a q-axis current calculation unit that calculates a command value; and a d-axis current calculation unit that calculates a d-axis current command value according to the rotor speed, the d-axis current calculation unit includes: The sign of the calculated pre-correction d-axis current command value is determined, and when the pre-correction d-axis current command value is positive or negative, the corresponding magnetoresistive bias value is determined, and the pre-correction d-axis current command value is determined. The d-axis current command value is calculated by correcting with the magnetoresistive bias value , and the d-axis current calculation unit further calculates the pre-correction when the sign of the pre-correction d-axis current command value is positive. d-axis current command value is positive magnetoresistive via Is corrected by a value, the sign of the uncorrected d-axis current command value is corrected by the negative magnetoresistance bias value the uncorrected d-axis current command value in the case of negative.
[0009]
In the present invention, the d-axis current calculation unit further determines the magnetoresistive bias value based on a d-axis current- d-axis inductance characteristic of the electric motor.
[0010]
In the present invention, the d-axis current calculation unit can achieve the object by determining the magnetoresistive bias value based on the magnetizing force-magnetic flux density characteristics of the rotor.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. Unless otherwise noted, the same elements and functions are denoted by the same reference numerals as in FIG.
[0012]
FIG. 1 is a block diagram of a motor control apparatus showing an embodiment of the present invention. Since the q-axis current calculation unit 1 is equivalent to the prior art, description thereof is omitted. The d-axis current calculation unit 2 receives the q-axis current command value SIQC, the d-axis current detection value SIDD, the q-axis current detection value SIQD, and the rotor speed SPD.
The d-axis current calculation unit 2 is roughly divided into a magnetic flux reduction rate calculation unit 6 and a magnetic flux / d-axis current conversion unit 12 having functions equivalent to those of the prior art, and further includes a magnetic flux command calculation unit 4 and a field of the present invention. There are a voltage bias calculation unit 15 as a magnetic current correction value calculation unit and a magnetoresistive bias calculation unit 16 as a field current bias calculation unit. The voltage bias calculation unit 15 and the magnetoresistance bias calculation unit 16 are provided in more detailed control blocks. Although detailed description is possible, a detailed description will be given later.
[0013]
Hereinafter, the operation in the d-axis current calculation unit 2 will be described according to the flow of the control block diagram.
[0014]
A q-axis current command value SIQC is input from the q-axis current calculation unit 1 to the magnetic flux command calculation unit 4, and the magnetic flux command SID is output in the magnetic flux command calculation unit 4 according to a function that refers to the q-axis current command value SIQC.
Although not particularly illustrated, the magnetic flux command SID applies a function of a linear equation or a quadratic equation to the q-axis current command value SIQC, and may take a constant value depending on the use of the motor. Also, an arbitrary threshold value may be set for the q-axis current command value SIQC, and the function may be changed with the threshold value as a boundary. For example, the q-axis current command value SIQC can be set to a quadratic expression if it is below the threshold, a primary expression if it is above the threshold, or a primary expression below the threshold, or a constant value above the threshold is there.
[0015]
Next, a voltage estimator 3 and a voltage bias calculator 5 are provided in the voltage bias calculator 15, and the q-axis current detection value SIQD, the d-axis current detection value SIDD, and the rotor speed SPD are supplied to the voltage estimator 3. Entered. Although not shown, the electric motor is provided with a position detector for detecting the position of the rotor, and the rotor speed SPD is obtained, for example, by differentiating the rotor position signal. Further, the q-axis current detection value SIQD and the d-axis current detection value SIDD are detected by, for example, a three-phase AC current value supplied to the electric motor (not shown), and coordinated on the dq axis using the rotor position signal. Calculated by performing conversion.
[0016]
In the voltage estimator 3, the d-axis current detection value SIQD, the d-axis current detection value SIDD, the rotor speed SPD and the preset d-axis and q-axis inductance values are referred to according to a known voltage equation. The shaft voltage and the q-axis voltage are calculated, and the voltage value SVD between the terminals of the motor is output as the combined voltage.
[0017]
The voltage bias value SIDC1 as the field current correction value calculated by the voltage bias calculator 5 with reference to the voltage value SVD between the terminals of the motor is added to the magnetic flux reduction coefficient SKID calculated by the magnetic flux reduction rate calculation unit 6 The post-bias reduction coefficient SKIDC, which is added by the unit 11 and is the output thereof, is multiplied by the magnetic flux command value SID and the multiplier 9, and becomes the pre-correction magnetic flux command value SID1 as the pre-correction field current command value.
[0018]
In the magnetoresistive bias calculator 16, the polarity of the pre-correction magnetic flux command value SID 1 is determined by the sign determiner 8 and the sign value SPN is input to the magnetoresistive bias calculator 7, and the magnetoresistive bias calculator 7 receives the sign value SPN. The magnetoresistive bias value SIDC2 is output as the field current bias value determined according to the polarity.
This magnetoresistive bias value SIDC2 is added by the adder 10 with the pre-correction magnetic flux command SID1 and outputs the d-axis current command value SIDC via the magnetic flux / d-axis current conversion unit 12 as the post-correction magnetic flux command SID2.
[0019]
The calculated d-axis current command value SIDC and q-axis current command value SIQC are, for example, not shown, but are converted into a three-phase AC current command value by coordinate conversion according to the rotor position. Current command value is supplied to the inverter and supplied to the electric motor as a PWM signal.
[0020]
FIG. 2 shows an example of a motor rotor model to which the present invention is applied. For convenience of explanation, a two-pole motor will be described, but 2n poles (n is an integer) has the same principle.
[0021]
The rotor 28 is made of a soft magnetic material such as a silicon steel plate, and has a structure in which a nonmagnetic material or a slit-like gap 29 is provided in order to provide a difference in magnetic resistance.
Usually, there is a stator made of a soft magnetic material outside the rotor 28, and a magnetic flux is generated by applying a current to a winding wound around the stator, and the magnetic flux passes through the rotor. Rotating force is obtained by doing.
[0022]
The current phase in which the magnetic flux easily passes through the winding to which the current is applied is set as the d axis, and the current phase in which the magnetic flux does not easily pass is set as the q axis, and the windings CDP and CDN on the d axis and the winding on the q axis are set. When a current is applied in the direction shown in the figure to CQP and CQN (circles indicate current in the front direction and currents in circle indicate a current in the back direction), magnetic flux CMF is generated, and the magnetic flux is generated in the rotor 28. Since it passes, the rotor 28 moves in a direction in which the magnetic flux easily passes, so that a rotational force RD is obtained.
Therefore, it is possible to control the rotational torque by controlling the magnitude of the current on each d-axis and q-axis.
[0023]
In FIG. 2, a reluctance type motor (RM) having no permanent magnet in the rotor 28 is modeled. However, although not shown in the drawing, a permanent magnet interior type (IPM) motor in which a permanent magnet is inserted in the air gap 29 is shown. The same control can be applied. However, in that case, it is necessary to control the magnetic flux component of the permanent magnet on the d-axis.
[0024]
FIG. 3 is a view showing a structural example of a rotor of an electric motor to which the present invention is applied.
The positional relationship between the soft magnetic material constituting the rotor 28 and the air gap 29 is as shown in FIG. 4A. When the interval FB1 between the outer periphery of the rotor 28 and the air gap 29 is narrow, the magnetic flux CMF applied from the stator is in each magnetic path. Although it is possible to pass without interference, since the distance FB1 is narrow, the strength of the rotor 28 itself cannot be secured, and this leads to an increase in the number of man-hours required for reinforcement in production. Thus, the rotor structure as shown in FIG.
[0025]
In this case, since the distance FB2 between the outer peripheral portion of the rotor 28 and the air gap 29 becomes large and magnetically becomes a bridging portion, the degree of freedom in the rotor 28 of the magnetic flux CMF from the stator increases, and the bridge As a result, magnetic fluxes interfere with each other in order to pass through each magnetic path as well as the entangled portion.
[0026]
FIG. 4 shows an example of electrical characteristics of the rotor 28 structure shown in FIG.
(A) shows the characteristic by d-axis current Id of d-axis inductance Ld (equivalent to SIDD on the control block of FIG. 1). The characteristic curve LD1 shows the inductance change in the case of the rotor structure of FIG. 3 (a), and the characteristic curve LD2 shows the inductance change in the case of the rotor structure of FIG. 3 (b).
Similarly, (b) shows the characteristic of the q-axis inductance Lq due to the q-axis current Iq (equivalent to SIQD on the control block of FIG. 1), and the characteristic curve LQ1 shows the inductance change in the case of the rotor structure of FIG. The characteristic curve LD2 shows the inductance change in the case of the rotor structure of FIG.
[0027]
As can be seen from FIG. 4 (a), in the case of a rotor (FIG. 3 (b)) having a magnetic bridging portion on the outer periphery of the rotor, the change in inductance Ld has a peak value in a region where the d-axis current Id is small. In FIG. 4B, it can be confirmed that the current increases when the q-axis current is small. This means that the characteristics of the d-axis inductance Ld and the q-axis inductance Lq are influenced by the rotor structure, in particular, the magnetic bridge portion on the outer periphery of the rotor.
[0028]
Normally, the torque of a motor that uses reluctance torque is proportional to (Ld−Lq) × Id × Iq, where d-axis inductance is Ld, q-axis inductance is Lq, d-axis current is Id, and q-axis current is Iq. From the characteristics of FIGS. 4A and 4B, it can be explained that when the d-axis current Id and the q-axis current Iq are small, the inductance difference between the d-axis and the q-axis is small. Therefore, it can be said that the torque is also reduced.
[0029]
FIG. 5 shows an H-B (magnetizing force-magnetic flux density) characteristic diagram of the soft magnetic material constituting the rotor 28. When the magnetizing force H is small, there is a region REG1 where the characteristic curve BHC changes sharply. In comparison with the region REG2 where a stable magnetic flux can be obtained with respect to the applied current, the region tends to be unstable in terms of control and hardly generates torque.
For reference, when the control is performed within the region REG1, the rate of change of the magnetic flux with respect to the applied current is large, which may cause torque ripples or cause irregularities due to uneven rotation.
[0030]
Even in the case of a rotor structure without a magnetic bridge as shown in FIG. 3 (a), when the applied current is low due to the magnetic properties of the soft magnetic material constituting the rotor 28. It is confirmed that the torque is not generated or the torque with respect to the applied current is small.
[0031]
Therefore, the purpose of this embodiment is to avoid the torque reduction region and the unstable control region as described above by applying a bias to the d-axis current Id. The d-axis in FIG. The current value calculated from the current bias value IDBIAS and the magnetizing force value at the boundary between the regions REG1 and REG2 in FIG. 5 becomes the magnetoresistive bias value SIDC2 calculated by the magnetoresistive bias calculating unit 16 in the control block diagram of FIG. Accordingly, stable d-axis current control can be obtained.
For example, the d-axis current bias value IDBIAS is set based on Id where the slope of the d-axis current Id-d-axis inductance Ld characteristic is equal to or greater than a threshold when Id is decreased. In addition, the magnetization force value at the boundary between the regions REG1 and REG2 is, for example, H or HB when the slope of the HB (magnetization force-magnetic flux density) characteristic is equal to or greater than a threshold when H is decreased. The magnetic resistance is set based on the value of H at which the amount of change in the slope of the (magnetizing force-magnetic flux density) characteristic is greater than or equal to the threshold, and the distance between the stator winding and the magnetic flux passage portion of the rotor. A bias value SIDC2 is set.
[0032]
FIG. 6 shows an example of the effect of this embodiment. The current-torque characteristic curves when the present embodiment is applied and not applied are TQ1 and TQ2, respectively, and the q-axis current Iq is low. In this case, in particular, it became possible to avoid a dead zone having a size of δIq. In addition, since the d-axis current is excessively supplied by the amount corresponding to the bias, the torque is increased.
[0033]
FIGS. 7A to 7C illustrate the function of the voltage bias calculation unit 15 shown in FIG. 1, and the operation will be described by showing examples of functions in each block diagram.
FIG. 7A shows an example of a function in the magnetic flux reduction rate calculation unit 6, and calculates the magnetic flux reduction coefficient SKID with reference to the rotor speed SPD. In FIG. 7A, the function is set to be inversely proportional to the constant value and the rotor speed SPD with the threshold value SPDB as a boundary.
[0034]
Next, FIG. 7B shows a function example in the voltage bias calculation unit 5, and outputs the voltage bias value SIDC 1 with reference to the voltage value SVD between terminals of the electric motor. In FIG. 7 (b), a linear expression is set that changes the slope at the threshold value SVDB.
[0035]
In this way, the magnetic flux reduction coefficient SKID and the voltage bias value SIDC1 are added by the adder 11 of FIG. 1, but the adder 11 performs a negative addition in this embodiment and actually functions as a subtracter. Therefore, the voltage bias value SIDC1 is subtracted from the magnetic flux reduction coefficient SKID.
[0036]
FIG. 7C shows an example of the calculation result. Since the voltage bias value SIDC1 increases when the voltage between the motor terminals is large, the post-bias reduction coefficient SKIDC may be a negative value as illustrated. is there.
This phenomenon is not an operational error, and the d-axis current functions as a field weakening field, especially when the rotor has a field component such as a permanent magnet in advance, as in a permanent magnet interior (IPM) type motor. Means.
[0037]
FIGS. 8A and 8B show the internal function of the magnetoresistive bias calculator 16 shown in FIG.
For convenience of explanation, when the magnetic flux command value SID = 1, the post-bias reduction coefficient SKIDC in FIG. 7C is multiplied by the multiplier 9 to obtain a pre-correction magnetic flux command SID1, which is input to the adder 10. Shall.
[0038]
FIG. 8A illustrates the processing in the magnetoresistive bias calculator 16. The magnetoresistive bias calculator 16 receives the sign value SPN in which the pre-correction magnetic flux command SID1 is sign-determined by the sign determiner 8, and when the sign polarity is positive, the magnetoresistive bias value SIDC2 = positive bias value BIASP. If negative, the magnetoresistive bias value SIDC2 is output to the adder 10 as a negative bias value BIASN.
[0039]
Note that the absolute values of the bias values do not necessarily have to be equal, that is, it is not necessary to be | positive bias value BIASP | = | negative bias value BIASN |. The characteristics of the motor, the soft magnetic material constituting the rotor 28 The numerical value can be changed according to the characteristics of
[0040]
FIG. 8B shows the result of correcting the magnetoresistive bias value SIDC2 with respect to the curve 63 of FIG. 7C. Compared with the curve 63, the curve 73 has a positive magnetoresistive bias value BIASP and a negative magnetoresistive bias value BIASN corrected for positive and negative, respectively.
As described above, the effects described with reference to FIGS. 4 to 6 can be obtained by correcting the d-axis current with the magnetoresistive bias value.
[0041]
9A and 9B are diagrams for explaining the effect of the voltage bias calculation unit 15 of FIG. 1, and the processing is as described in FIG.
FIG. 9A shows a current command waveform and a current response waveform for one phase. When this embodiment is not applied, the current response waveform 82 is delayed in phase with respect to the current command waveform 81, and the amplitude also responds. Not done.
When this embodiment is applied, the current response waveform 84 can follow the current command waveform 83 in both amplitude and phase. The ripple superimposed on the current response waveforms 82 and 84 depends on the PWM frequency and the winding inductance to which the current is applied. In an electric motor having a high PWM frequency and a high winding inductance (the number of windings is large). I don't care.
[0042]
FIG. 9B shows the voltage as a dq axis vector. When the voltage cannot be controlled within the voltage limit circle 85 of the power supply (vector VO), the current command is shown as shown in FIG. 9A. As a result, the current response waveform 82 does not follow the waveform 81. In this embodiment, a negative bias is applied to the d-axis current. That is, in the voltage equation, attention is paid to a term related to the d-axis current Id. The angular velocity of the child is ω, the d-axis inductance is Ld, and the term of ω × Ld × Id in the q-axis voltage component is reduced (vector VOD). In particular, in a reluctance motor having a large d-axis inductance Ld included in the term of q-axis voltage, the reduction of the d-axis current Id has a great effect on reducing the voltage between the motor terminals.
[0043]
【The invention's effect】
According to the present invention as described above, calculates a magnetic flux command value with reference to the q-axis current command value calculated by the q-axis current calculation portion, d-axis current detection value by more current detecting means and the q-axis current detection The voltage bias value is calculated from the voltage value obtained by the voltage estimator that estimates the voltage value between the terminals of the electric motor with reference to the value and the rotor speed, and the magnetic flux command value is corrected with the voltage bias value to obtain the d-axis current command. By calculating the value, it becomes possible to avoid instability of control due to voltage saturation. Further, to determine the sign of the uncorrected d-axis current command value in the d-axis current calculation portion calculates a magnetoresistive bias value corresponding to the respective cases of positive and negative pre-correction d-axis current command value before correction d-axis By correcting the current command value with the magnetoresistive bias value and calculating the d-axis current command value, it is possible to avoid a current-torque non-linear region due to the magnetic structure of the motor rotor and the magnetic characteristics of the material. It becomes possible. Therefore, by adopting one of the above configurations, an electric motor control device having stable controllability can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram of a motor control device according to an embodiment of the present invention.
FIG. 2 is a model diagram of an electric motor to which the electric motor control device according to the embodiment of the present invention is applied.
FIG. 3 is a detailed view of an electric motor model to which the electric motor control device according to the embodiment of the present invention is applied.
FIGS. 4A and 4B are diagrams showing inductance characteristics of a motor applied to the motor control apparatus according to the embodiment of the present invention ((a) d axis, (b) q axis).
FIG. 5 is a diagram showing HB (magnetizing force-magnetic flux density) characteristics of a soft magnetic material constituting the electric motor applied to the electric motor control apparatus according to the embodiment of the present invention.
FIG. 6 is a diagram for explaining the application effect of the motor control device according to the embodiment of the present invention.
FIG. 7 is a diagram illustrating an example of functions in a control block of the motor control device according to the embodiment of the present invention.
FIG. 8 is a diagram illustrating a function example in a control block of the motor control device according to the embodiment of the present invention.
FIG. 9 is a diagram for explaining an application effect of the motor control device according to the embodiment of the present invention.
FIG. 10 is a block diagram showing a conventional motor control device.
[Explanation of symbols]
1 q-axis current calculation unit, 2 d-axis current calculation unit, 3 voltage estimator, 4 magnetic flux command calculation unit, 5 voltage bias calculation unit, 6 magnetic flux reduction rate calculation unit, 7 magnetoresistive bias calculation unit, 8 sign determination unit, 9 multiplier, 10, 11 adder, 12 magnetic flux / d-axis current converter, 13 torque command limiter, 14 torque / q-axis current converter, 15 voltage bias calculator, 16 magnetoresistive bias calculator, 28 rotor (Soft magnetic material), 29 air gap (non-magnetic material), 61, 62, 63 function, 81, 83 current command waveform, 82, 84 current detection waveform, 91 magnetic flux command generator, STC torque command value, STCC corrected torque Command value, SIQC q-axis current command value, SIDC d-axis current command value, SIQD q-axis current detection value, SIDD d-axis current detection value, SPD rotor speed, SID magnetic flux command, SID1 magnetic flux command before correction, S D2 Corrected magnetic flux command, SKIDC Post bias reduction coefficient, SIDC1 voltage bias value, SIDC2 magnetoresistive bias value, SKID magnetic flux reduction coefficient, SPN sign value, SVD terminal voltage value, CDP, CDN d-axis winding, CQP, CQN q Axis winding, CMF winding magnetic field, RD rotational force, FB1, FB2 Rotor outer circumference-slit distance (bridge), LD1, LD2 d-axis inductance characteristics, LQ1, LQ2 q-axis inductance characteristics, BHC, H-B (Magnetizing force-magnetic flux density) characteristics, REG1, REG2 control region, TQ1, TQ2 generated torque, BIASP, BIASN bias value, VO pre-correction voltage vector, VOD post-correction voltage vector.

Claims (5)

A control device for an electric motor comprising a rotor having a soft magnetic material and having an inductance change as seen from the stator winding in the rotation direction,
Speed detecting means for detecting the rotor speed ;
And the q-axis current calculating unit for calculating a q-axis current command value from the torque command value commanded from the top level control device,
A d-axis current calculation unit for calculating a d-axis current command value according to the rotor speed;
Current detection means for detecting d-axis current and q-axis current of the motor;
In an electric motor control device comprising:
The d-axis current calculator is
A magnetic flux command calculation unit for calculating a magnetic flux command value with reference to the q-axis current command value;
A voltage estimator for estimating the inter-terminal voltage value of the motor with reference to the rotor speed and the d-axis current detection value and a q-axis current detection value by the current detecting means,
With
Calculating a voltage bias value from the voltage value between the terminals, the magnetic flux command value control unit for an electric motor, wherein the benzalkonium to calculate the d-axis current command value corrected by the voltage bias value. The motor control device according to claim 1,
The d-axis current calculation unit corrects the magnetic flux reduction coefficient calculated with reference to the rotor speed with the voltage bias value , and corrects the magnetic flux command value with the corrected magnetic flux reduction coefficient, thereby correcting the d-axis current. An electric motor control device that calculates a current command value. For an electric motor including a rotor having a soft magnetic body and having an inductance change as seen from the stator winding in the rotation direction,
And the q-axis current calculating unit for calculating a q-axis current command value from the torque command value commanded from the host controller,
A d-axis current calculation unit for calculating a d-axis current command value according to the rotor speed;
In an electric motor control device comprising:
The d-axis current calculation unit determines the sign of the calculated d-axis current command value before correction, determines a magnetoresistive bias value corresponding to each of the positive and negative d-axis current command values, and the correction The d-axis current command value is calculated by correcting the previous d-axis current command value with the magnetoresistive bias value ,
Further, the d-axis current calculation unit corrects the d-axis current command value before correction with a positive magnetoresistive bias value when the sign of the d-axis current command value before correction is positive, and the d-axis current before correction. When the sign of the command value is negative, the d-axis current command value before correction is corrected with a negative magnetoresistive bias value . In the motor control device according to claim 3,
The d-axis current calculation unit determines the magnetoresistive bias value based on a d-axis current- d-axis inductance characteristic of the motor. In the motor control device according to claim 3,
The d-axis current calculation unit determines the magnetoresistive bias value based on a magnetizing force-magnetic flux density characteristic of the rotor.

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