JP6514969B2 - Vector controller for permanent magnet synchronous motor - Google Patents

Description

  The present invention relates to a vector control device of a permanent magnet synchronous motor having a permanent magnet as a field, and in particular, vector control of a permanent magnet synchronous motor controlling operation of a permanent magnet synchronous motor according to an estimated value of magnet magnetic flux. It relates to the device.

  Generally, in a vector control device of a permanent magnet type synchronous motor, current values and inductance values of d axis and q axis which are rotating coordinate system, and interlinking magnetic flux (hereinafter referred to as "magnet magnetic flux") by permanent magnets The motor is driven by the output torque controlled accordingly. However, it is known that the magnet flux decreases with the temperature rise of the permanent magnet. In addition, the d-axis and q-axis inductances have a characteristic of fluctuating due to the influence of magnetic saturation when the current changes. Therefore, the values of the magnet magnetic flux and the values of the inductances change according to the operation condition of the motor, and therefore, when the change can not be reflected, the accurate control of the output torque is disturbed.

  In Patent Document 1, as a measure for the fluctuation of the magnet magnetic flux due to the temperature rise of the permanent magnet, an estimated value of the amount of change of the magnet magnetic flux is obtained using the deviation of the voltage value of q axis, A method of controlling output torque is disclosed. The method of Patent Document 1 performs an operation on the premise that the inductance of the d axis is known.

  On the other hand, Patent Document 2 discloses a method of vector control for estimating a magnet magnetic flux using reactive power obtained by calculation. That is, it corresponds to a two-step value of “positive” and “negative” set as a d-axis current using a predetermined relational expression (refer to equation (2) described later) of reactive power, magnet magnetic flux and inductance By calculating two reactive power values, it is possible to estimate the magnet magnetic flux without being affected by the fluctuation or variation of the inductance (for example, see paragraphs 51 to 53 of Patent Document 2).

Japanese Patent Application Laid-Open No. 10-229700 JP, 2007-159212, A

  In Patent Document 1, the inductance of the d axis is less susceptible to the influence of the current conditions than the inductance of the q axis, and the inductance value is stable. Therefore, the estimation accuracy can be stably maintained regardless of the current conditions. I can expect it. However, this method has not taken into consideration the variation in inductance due to individual differences in the motor.

  By employing the method of Patent Document 2, it is possible to easily estimate the magnetic flux of the magnet. However, the estimation of the magnet magnetic flux is limited due to the setting condition of the d-axis current when calculating the estimated value of the reactive power. FIG. 4 is a vector diagram in the case where the current Id of the d-axis is set negative (FIG. 4 (A)) and when it is set positive (FIG. 4 (B)) in the vector control of Patent Document 2. Is a diagram illustrating an example of In FIG. 4, d-axis and q-axis current Id, Iq, motor applied voltage (terminal voltage) Vo and motor applied current (terminal current) Io, motor angular velocity ω, magnet magnetic flux φm, armature linkage flux φa, d The inductances Ld and Lq of the axis and the q axis, and the current phase angle β are each displayed in a vector diagram. As shown in FIG. 4, due to the directivity of Ld · Id, the magnitude of the applied voltage Vo of the motor is greater when the d-axis current is negative than when the d-axis current is negative. It turns out that it rises sharply. Therefore, there is a problem that the operation of FIG. 4B becomes practically difficult due to the limitation of the voltage value applied to the motor, particularly in the operation region where the rotation of the motor becomes high. As described above, in the vector control device of the conventional permanent magnet synchronous motor, a method capable of estimating the magnet flux with high accuracy under various operating conditions of the motor without being affected by the fluctuation of the inductance is used. It could not be realized.

  The present invention has been made to solve these problems, and can be applied under various operating conditions such as a wide range of rotation of a motor while taking into consideration variations in inductance, and magnet flux can be accurately obtained. It is an object of the present invention to provide a vector control device of a permanent magnet synchronous motor which can estimate.

  In order to solve the above problems, according to a first aspect of the present invention, an output voltage of an inverter (14) for driving a permanent magnet synchronous motor (16) having a permanent magnet as a field according to a torque command (Tr) A vector control device for a permanent magnet synchronous motor that performs vector control, comprising: voltages (Vd, Vq) or voltage command values of the d axis and q axis that are rotating coordinate systems, and supplied from the inverter to the permanent magnet synchronous motor Reactive power acquisition means (20) for calculating or detecting reactive power of the permanent magnet synchronous motor based on detected values (Iu, Iv, Iw) of current, and d-axis current corresponding to the detected value of the current Magnet flux estimation means (21) for estimating a magnet flux (磁 束 m) which is a linkage flux by the permanent magnet based on the reactive power and the angular velocity of the permanent magnet synchronous motor; When estimating the magnetic flux, while making the q-axis current corresponding to the detected value of the current a constant value other than zero, and changing the d-axis current to a plurality of negative values (Id1, Id2, Id3), It is characterized in that the permanent magnet synchronous motor is driven.

  According to the first aspect of the present invention, when estimating the magnet flux, control is performed so that the d-axis current is changed to a plurality of negative values while the q-axis current is a constant value that is not zero. Therefore, it is possible to estimate the magnet flux with high accuracy without being affected by the fluctuation of the inductance in a wide high rotation area of the motor while suppressing the voltage applied to the motor. Further, according to the first aspect, it is possible to estimate the magnet flux in an operating state in which torque is generated in the motor.

  In the first aspect of the present invention, when the magnet flux estimating means sets currents of the d axis to three different values Id1, Id2, and Id3 different from each other with respect to the current Iq of the q axis, the Id1, Id2 , And the ternary value ω1, ω2, ω3 of the angular velocity corresponding to the Id1, Id2, Id3 and the reactive power ternary value Q1, Q2, Q3, respectively, to calculate the equation (6) described later By doing this, the magnet magnetic flux .phi.m can be estimated. Further, at this time, when the magnet magnetic flux estimating means can be regarded as ω1 = ω2 = ω3 regarding the ternary values ω1, ω2, ω3 of the angular velocity, the magnet magnetic flux can be calculated by calculating the equation (7) described later. The φ m can be estimated.

  In order to solve the above-mentioned subject, the 2nd mode of the present invention makes output voltage of inverter (14) which drives a permanent magnet synchronous motor (16) which has a permanent magnet as a field according to torque command (Tr) A vector control device for a permanent magnet synchronous motor that performs vector control, comprising: voltages (Vd, Vq) or voltage command values of the d axis and q axis that are rotating coordinate systems, and supplied from the inverter to the permanent magnet synchronous motor Reactive power acquisition means (20) for calculating or detecting reactive power of the permanent magnet synchronous motor based on detected values (Iu, Iv, Iw) of current, and d-axis current corresponding to the detected value of the current Magnet flux estimation means (21) for estimating a magnet flux (磁 束 m) which is a linkage flux by the permanent magnet based on the reactive power and the angular velocity of the permanent magnet synchronous motor; When estimating the magnetic flux, the q-axis and d-axis currents corresponding to the detected values of the current are represented by a plurality of points ((Id1, Iq1), (Id2, Iq2), (Id3, Iq3) on a constant torque curve (Ct). The permanent magnet synchronous motor is driven while changing to)).

  According to the second aspect of the present invention, in the estimation of the magnet magnetic flux, the d-axis and q-axis currents are controlled to be changed to a plurality of points of the constant torque curve. In addition to being able to estimate the magnet flux with high accuracy in a wide high-speed region, the magnet flux can be estimated in an operating state in which the torque fluctuation is sufficiently suppressed.

  In the second aspect of the present invention, the magnet magnetic flux estimating means determines the q-axis and d-axis currents at three points (Id1, Iq1), (Id2, Iq2), (Id3, Iq3) on the constant torque curve. By setting equation (11) described later using three values Q1, Q2, Q3 of the reactive power and three values .omega.1, .omega.2, .omega.3 of the angular velocity corresponding to the three points. The magnet flux φm can be estimated. Further, at this time, when the magnet magnetic flux estimating means can be regarded as ω1 = ω2 = ω3 regarding the ternary values ω1, ω2, ω3 of the angular velocity, the magnet magnetic flux can be calculated by calculating the equation (12) described later. The φ m can be estimated.

  According to the present invention, it is possible to prevent torque from being generated in the motor without being restricted by the voltage applied to the motor under various operating conditions such as a wide rotation area of the motor while avoiding the influence of the fluctuation of the inductance. It is possible to realize a vector control device of a permanent magnet synchronous motor capable of accurately estimating the magnet flux.

FIG. 1 is a block diagram showing a schematic overall configuration of a vector control device for a permanent magnet synchronous motor according to an embodiment of the present invention. It is a figure which shows an example of the vector diagram in the vector control using the 1st estimation method of this embodiment. It is a figure which shows an example of the vector diagram in the vector control using the 2nd estimation method of this embodiment. It is a figure which shows the example of the vector diagram in vector control of patent document 2. FIG.

  Preferred embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below is an example of a form to which the present invention is applied, and the present invention is not limited by the contents of the present embodiment.

  Hereinafter, a vector control device of a permanent magnet synchronous motor according to an embodiment to which the present invention is applied will be described. FIG. 1 is a block diagram schematically showing the overall configuration of a vector control device for a permanent magnet synchronous motor according to the present embodiment, and shows a current command generation unit 10, a current control unit 11, and a two-phase / three-phase conversion unit 12 The PWM operation unit 13, the inverter 14, the current detection unit 15, the motor 16, the rotation angle detection unit 17, the three-phase / two-phase conversion unit 18, the angular velocity operation unit 19, and the reactive power operation unit 20 And a configuration including the magnet flux estimation unit 21.

In FIG. 1, the current command generation unit 10 generates current command values Id ^* and Iq ^* of the d axis and the q axis, which are two-phase rotational coordinate systems, based on the torque command Tr received from the outside. Taking the case where the motor 16 of FIG. 1 is mounted on an electric vehicle as an example, the torque command Tr input to the current command generation unit 10 changes in conjunction with the accelerator operation amount. Further, since the magnet magnetic flux φm estimated by the magnet magnetic flux estimation unit 21 described later is fed back to the current command generation unit 10, the current command generation is performed even when the magnet magnetic flux φm changes due to temperature fluctuation of the permanent magnet. The above-mentioned command values generated by the unit 10 are controlled to compensate appropriately.

The current control unit 11 includes a pair of subtraction units 11a and 11b and a PI control calculation unit 11c. The subtractors 11a and 11b calculate the d-axis and q-axis currents Id output from the three-phase / two-phase converter 18 described later from the current command values Id ^* and Iq ^* output from the current command generator 10. Iq is respectively subtracted to output current deviations ΔId and ΔIq. PI control operation unit 11 c executes PI (Proportional and Integral) control using a well-known relational expression, and current deviations ΔId and ΔIq from subtraction units 11 a and 11 b and angular velocity ω output from angular velocity calculation unit 19 The voltage command values Vd ^* and Vq ^* of the d axis and the q axis are respectively calculated based on

Based on the rotation angle θ of the motor 16 detected by the rotation angle detection unit 17, the two-phase / three-phase conversion unit 12 calculates a voltage command value Vd ^* of two phases in the rotation coordinate system represented by the d axis and the q axis. Coordinate conversion of Vq ^* is performed, and voltage command values Vu ^* , Vv ^* , Vw ^* of three-phase alternating current represented by u phase, v phase, w phase are output.

The PWM operation unit 13 and the inverter 14 generate three-phase AC output voltages for driving the motor 16 based on the voltage command values Vu ^* , Vv ^* , Vw ^* output from the two-phase / three-phase conversion unit 12 Do. Note that the output voltages of the three-phase alternating current are in a phase-shift relationship of 120 ° with each other. The inverter 14 includes, for example, switching elements (not shown) such as a plurality of transistors whose switching is controlled according to the PWM control signal generated by the PWM operation unit 13, and the output side thereof includes u phase, v phase and w phase It is electrically connected to the input side of the motor 16 through the respective three-phase wires.

  The current detection unit 15 detects currents Iu, Iv, and Iw of the three-phase wirings flowing from the inverter 14 to the motor 16. The current detection unit 15 can detect each current by using, for example, a magnetic field generated in the vicinity of each of the three-phase wirings.

  The motor 16 includes a rotor using a permanent magnet as a field and a stator that generates a rotating magnetic field by three-phase alternating current supplied from the inverter 14, and is a permanent magnet that rotates in synchronization with the three-phase alternating current frequency. Type synchronous motor. Further, the rotation angle detection unit 17 attached to the motor 16 detects the above-described rotation angle θ as the position of the rotor of the motor 16.

  The three-phase / two-phase conversion unit 18 coordinate-converts the three-phase currents Iu, Iv, Iw detected by the current detection unit 15 based on the rotation angle θ of the motor 16 detected by the rotation angle detection unit 17. The two-phase currents Id and Iq of the rotational coordinate system represented by the d axis and the q axis are output.

  The angular velocity calculation unit 19 outputs the above-described angular velocity ω of the motor 16 based on the rotation angle θ of the motor 16 detected by the rotation angle detection unit 17. The rotational speed of the motor 16 can be determined by this angular velocity ω.

ここで、（１）式は、回転座標系における電流及び電圧指令値の各ベクトルの外積の差に相当する。なお、本発明の無効電力取得手段は、（１）式に基づき演算した無効電力Ｑを用いることに限られず、センサにより検知した無効電力Ｑを用いることも可能である。 The reactive power calculation unit 20 is a unit (reactive power acquisition unit of the present invention) that calculates reactive power Q of the motor 16. In reactive power calculation unit 20, d-axis and q-axis currents Id and Iq output from the above-described 3-phase / 2-phase conversion unit 18 and d-axis and q-axis voltage command values output from current control unit 11 The reactive power Q can be calculated as in the following equation (1) using Vd ^* and Vq ^* .

Here, the equation (1) corresponds to the difference between the outer products of each vector of the current and voltage command values in the rotational coordinate system. The reactive power acquisition means of the present invention is not limited to using the reactive power Q calculated based on the equation (1), but it is also possible to use the reactive power Q detected by a sensor.

  The magnet flux estimation unit 21 is means for estimating the magnet flux φm based on the reactive power Q output from the reactive power calculation unit 20 (a first magnet flux estimation unit of the present invention). A specific estimation method in the magnet flux estimation unit 21 will be described later. The magnet flux φm output from the magnet flux estimation unit 21 is sent to the current command generation unit 10 described above.

Next, a first estimation method of the magnet flux φm by the magnet flux estimation unit 21 of FIG. 1 will be described. First, the reactive power Q is expressed by the following equation (2) using the currents Id and Iq in the d axis and q axis, and the inductances Ld and Lq in the d axis and q axis, the magnet magnetic flux φm, and the angular velocity ω. Can.

なお、上記Ｉｄ１、Ｉｄ２、Ｉｄ３は、ｄ軸及びｑ軸のインダクタンスＬｄ、Ｌｑの変動が小さい範囲内に設定されるものとする。これにより、（３）〜（５）式において、ｄ軸の電流Ｉｄの３値Ｉｄ１、Ｉｄ２、Ｉｄ３に対応して、３つの無効電力Ｑ１、Ｑ２、Ｑ３と、３つの角速度ω１、ω２、ω３が得られる。 Then, while setting the q-axis current Iq to a constant value, drive the motor 16 while setting different ternary values Id1, Id2, and Id3 as the d-axis current Id, and perform the calculation of equation (2) respectively. . Thus, the following equations (3) to (5) corresponding to the three values Id1, Id2, and Id3 are respectively calculated.

The above-mentioned Id1, Id2 and Id3 are set within a range where the fluctuation of the inductances Ld and Lq of the d-axis and q-axis is small. Thus, in the equations (3) to (5), three reactive powers Q1, Q2, and Q3 and three angular velocities ω1, ω2, and ω3 corresponding to the three values Id1, Id2, and Id3 of the current Id of the d axis. Is obtained.

In the above equations (3) to (5), since Ld, Lq, and φm can be regarded as constant, they can be calculated as simultaneous equations. As a result, in the magnet flux estimation unit 21, the following equation (6) is calculated for the magnet flux φm.

In the equation (6), when the motor 16 is driven as described above, the angular velocity ω gradually changes temporally, so that ω = ω1 = ω2 = ω3 can be regarded. In this case, the following equation (7) can be derived from the equation (6).

  As described above, in the magnet flux estimation unit 21, the reactive power Q received from the reactive power calculation unit 20, the d-axis and q-axis currents Id and Iq received from the 3-phase / 2-phase conversion unit 18, and the angular velocity calculation The angular velocity ω received from the unit 19 can be extracted respectively, and the calculation of the equation (6) or (7) can be performed as a first estimation method.

  FIG. 2 shows an example of a vector diagram in vector control using the first estimation method. In FIG. 2, the currents Id and Iq of the d axis and the q axis and the applied current Io of the motor 16 are displayed as in FIG. 4. As described above, since the q-axis current Iq is set to a constant value and the d-axis current Id is set to three values Id1, Id2, and Id3 on the d axis, the applied current Io of the motor 16 has a value Io1. Three points (Id1, Iq), values Io2 (Id2, Iq), and values Io3 (Id3, Iq) transition in parallel with the d axis.

  According to the first estimation method, since the d-axis current Id is set to a negative value at each of three points for driving the motor 16, the voltage applied to the motor 16 as shown in FIG. The rise of Vo can be prevented, and the magnet magnetic flux φm can be estimated with high accuracy in the high rotation region of the motor. Further, since the values of the inductances Ld and Lq are not used in the calculation of the equation (6) or (7), the variation of the inductance of the estimation accuracy of the magnet magnetic flux φm becomes a problem in the conventional estimation method (method of patent document 1) Impact can be avoided. Furthermore, since the q-axis current Iq is maintained at a constant value larger than zero, it is possible to estimate the magnet magnetic flux φm in a situation where the motor 16 is generating torque (for example, while the vehicle is traveling). In addition, as long as the above-described effects can be obtained, the q-axis current Iq can be set to a constant negative value other than zero.

Next, a second method of estimating the magnet flux φm by the magnet flux estimation unit 21 of FIG. 1 will be described. In the second estimation method, the above-mentioned equation (2) is common, but based on the equation (2), along the constant torque curve Ct (see FIG. 3) in which the torque of the motor 16 is kept constant, Three different values Io1, Io2 and Io3 are set as the applied current Io. The calculation of the constant torque curve Ct will be described later. Then, corresponding to the three values Io1, Io2 and Io3 set as described above, three points (Id1, Iq1) and (Id2) on the constant torque curve Ct by the combination of the currents Id and Iq of the d axis and q axis. , Iq2), and (Id3, Iq3), the following equations (8) to (10) are computed by performing the above-mentioned equation (2).

In the equations (8) to (10), three reactive powers Q1, Q2, and Q3 and three reactive powers are provided corresponding to three points determined by the d-axis and q-axis currents Id and Iq, as in the first estimation method. Angular velocities ω1, ω2, ω3 are obtained. Therefore, based on (8) to (10), the following equation (11) is obtained for the magnet magnetic flux φm.

In the equation (11), from the same viewpoint as the case of the equation (6), it can be regarded that ω = ω1 = ω2 = ω3, so the following equation (12) can be derived from the equation (11) .

  As described above, in the magnet flux estimation unit 21, the reactive power Q received from the reactive power calculation unit 20, the d-axis and q-axis currents Id and Iq received from the 3-phase / 2-phase conversion unit 18, and the angular velocity calculation The angular velocity ω received from the unit 19 can be extracted, and the calculation of the equation (11) or the equation (12) can be performed as a second estimation method.

  FIG. 3 shows an example of a vector diagram in vector control using the second estimation method. In FIG. 3, the currents Id and Iq of the d axis and the q axis and the applied current Io of the motor 16 are displayed. As described above, the applied current Io of the motor 16 has values Io1 (Id1, Iq1) and Io2 (Id2) along the constant torque curve Ct in accordance with the settings of the currents Id and Iq in the d and q axes. , Iq2) and the value Io3 (Id3, Iq3).

ただし、Ｐｎ：磁極対数 Here, in FIG. 3, a method of calculating the constant torque curve Ct will be described. In general, the torque T of the motor 16 can be expressed by the following equation (13) using the currents Id and Iq of the d axis and q axis, the inductances Ld and Lq, and the magnet magnetic flux φm.

However, Pn: pole number

In equation (13), assuming that torque T is a constant value (T = Tconst) and solving for Iq, the following equation (14) is derived.

  As understood from the equation (14), on the constant torque curve Ct, the currents Id and Iq of the d axis and the q axis are in inverse proportion to each other. From the above, after setting the desired constant value Tconst as the torque T, three points satisfying the relationship of the equation (14) are set as the currents Id and Iq of the d axis and the q axis, and the equation (11) or (12) It is sufficient to calculate the equation. The values of the currents Id and Iq on the constant torque curve Ct may be stored in the memory as map information.

  According to the second estimation method, three points for driving the motor 16 are set on the constant torque curve Ct. Therefore, in addition to the same effect as the first estimation method, the torque fluctuation of the motor 16 is sufficiently suppressed. The magnet magnetic flux φm can be estimated in the state described above.

Next, a modification of the vector control device of the permanent magnet type synchronous motor of the present embodiment will be described. In the above description, the motor 16 is driven at three points to estimate the magnet magnetic flux φm based on the first and second estimation methods, but in the present modification, map information stored in advance in memory is used The magnetic flux φm is calculated. Specifically, the reactive power Q is calculated or detected at an arbitrary timing, and the values of the currents Id and Iq of the d axis and q axis and the angular velocity ω are used, and the d axis and q axis held as map information The following equation (15) may be calculated by reading out the values of the inductances Ld and Lq.

  By adopting this modification, it is possible to reliably estimate the magnet magnetic flux φm with a small amount of calculation regardless of the operating state of the motor 16.

  As mentioned above, although the vector control device of the permanent magnet type synchronous motor concerning the present invention was explained based on this embodiment, the composition which can apply the present invention is not limited to the composition of Drawing 1, but various composition. The present invention is applicable to For example, in FIG. 1, in addition to the reactive power computing unit 20, an active power computing unit for computing the active power of the motor 16 is additionally provided to output both the reactive power and the active power, or A configuration for selectively outputting may be adopted.

  The vector control device for a permanent magnet synchronous motor according to the present invention can be used in various applications. For example, permanent magnet type provided with a configuration that compensates for the fluctuation of the magnetic flux in applications such as electric vehicles, motorbikes, mobile bodies such as trains, blowers, FA devices, industrial applications such as processing devices, elevators, air conditioners, etc. The present invention can be applied to a vector control device or the like of a synchronous motor.

DESCRIPTION OF SYMBOLS 10 ... Current command generation part 11 ... Current control part 11a, 11b ... Subtraction part 11c ... PI control calculating part 12 ... 2 phase / 3 phase conversion part 13 ... PWM calculating part 14 ... Inverter 15 ... Current detection part 16 ... Motor 17 ... Rotation angle detection unit 18 ... Three-phase / two-phase conversion unit 19 ... Angular velocity calculation unit 20 ... Reactive power calculation unit 21 ... Magnet flux estimation unit Tr ... Torque command Id, Iq ... d-axis and q-axis current Ld, Lq ... d Axis and q axis inductance Iu, Iv, Iw ... 3-phase AC current Q ... reactive power ω ... angular velocity φm ... magnet flux

Claims (6)

A vector control device for a permanent magnet synchronous motor, which vector controls an output voltage of an inverter for driving a permanent magnet synchronous motor having a permanent magnet as a field according to a torque command,
Calculates or detects reactive power of the permanent magnet synchronous motor based on d-axis and q-axis voltages or voltage command values that are rotational coordinate systems and detected values of current supplied from the inverter to the permanent magnet synchronous motor Means for acquiring reactive power,
Magnet flux estimation means for estimating a magnet flux which is a linkage flux by the permanent magnet based on the d-axis current corresponding to the detected value of the current, the reactive power, and the angular velocity of the permanent magnet synchronous motor; ,
In the estimation of the magnet flux, the q-axis current corresponding to the detected value of the current is a non-zero constant value, and the d-axis current is changed to a plurality of negative values while the permanent A vector control device for a permanent magnet synchronous motor, which drives a magnet synchronous motor. The magnet flux estimation means sets the currents of the d axis to three different values Id1, Id2 and Id3 different from each other with respect to the current Iq of the q axis, the reactive power of the reactive power corresponding to the Id1, Id2 and Id3. Using three values Q1, Q2, Q3 and three values ω1, ω2, ω3 of the angular velocity corresponding to Id1, Id2, Id3,

The vector control device for a permanent magnet synchronous motor according to claim 1, wherein the magnet magnetic flux? M is estimated by calculating? When the magnet magnetic flux estimating means can be regarded as ω1 = ω2 = ω3 regarding the three values ω1, ω2, ω3 of the angular velocity,

The vector control device for a permanent magnet synchronous motor according to claim 2, wherein the magnet magnetic flux? M is estimated by calculating? A vector control device for a permanent magnet synchronous motor, which vector controls an output voltage of an inverter for driving a permanent magnet synchronous motor having a permanent magnet as a field according to a torque command,
Calculates or detects reactive power of the permanent magnet synchronous motor based on d-axis and q-axis voltages or voltage command values that are rotational coordinate systems and detected values of current supplied from the inverter to the permanent magnet synchronous motor Means for acquiring reactive power,
Magnet flux estimation means for estimating a magnet flux which is a linkage flux by the permanent magnet based on the d-axis current corresponding to the detected value of the current, the reactive power, and the angular velocity of the permanent magnet synchronous motor; ,
And driving the permanent magnet synchronous motor while changing the d-axis and q-axis currents corresponding to the detected values of the current to a plurality of points on a constant torque curve when estimating the magnet magnetic flux. The vector control device of the permanent magnet synchronous motor which is characterized. The magnet flux estimation means sets the q-axis and d-axis currents to three points (Id1, Iq1), (Id2, Iq2), and (Id3, Iq3) on the constant torque curve. Using corresponding three values Q1, Q2, Q3 of the reactive power and three values ω1, ω2, ω3 of the angular velocity,

The vector control device for a permanent magnet synchronous motor according to claim 4, wherein the magnet magnetic flux? M is estimated by calculating? When the magnet magnetic flux estimating means can be regarded as ω1 = ω2 = ω3 regarding the three values ω1, ω2, ω3 of the angular velocity,

The vector control device for a permanent magnet synchronous motor according to claim 4, wherein the magnet magnetic flux? M is estimated by calculating?

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