JP5574925B2 - Position / speed sensorless control device - Google Patents

Description

  The present invention relates to a position / speed sensorless control device for an electric motor.

  The configuration of a conventional position / speed sensorless control device is shown in FIG.

  FIG. 11A shows a DC train driving device. This drive device receives electric power from an overhead wire by a pantograph 1 and supplies current to a reactor 3 and a capacitor 4 that serve as a smoothing filter. The VVVF inverter 5 converts the input direct current into alternating current and outputs the alternating current. The output drives a main motor 7 of a train such as an induction motor.

  An outline of the control system of this driving apparatus is shown below. This control system is a vector control system using a DQ axis rotation coordinate system as an example. FIG. 12 is an equivalent circuit diagram of the AC motor 7 (in the case of an induction motor). As shown in this figure, the induction motor 7 has a primary resistance R1, a primary self-inductance L1, a secondary resistance R2, and a secondary self-inductance L2.

  FIG. 13 is a diagram showing an outline of induction motor vector control. The inverter output voltage (motor applied voltage) V1 is equal to the sum of the induced voltage E of the motor and the voltage drop V2 due to the winding inductance of the stator. This voltage drop V2 is expressed by the following equation.

V2 = ω ・ σ ・ L1 ・ I
Here, σ is a leakage coefficient (= M ² / L1 / L2), ω is an inverter output angular frequency, and I is a current flowing through the motor. This current I is also shown as a vector I starting from the origin of the D and Q axes. The D axis indicates an axis in the direction of the secondary magnetic flux generated in the rotor by the drive current of the stator winding, and the Q axis is an axis orthogonal to the D axis.

  The D axis component of the current I generates magnetic flux, and the Q axis component generates torque. In the figure, Φ2 is the secondary magnetic flux of the rotor. The induced voltage E is generated on the Q axis because it is generated perpendicular to the secondary magnetic flux. This induced voltage E is represented by the product (= ω · Φ2) of the inverter output angular frequency ω and the secondary magnetic flux Φ2.

  Φ2 and torque Trq are expressed by the following equation.

Φ2 = Mutual inductance M / D axis current Id
Trq = (M / L2) · Φ2 · Iq · Pn
Here, Pn is the number of pole pairs. In the vector control of the induction motor, the current and voltage are controlled so that the D axis coincides with the secondary magnetic flux Φ2 of the rotor.

Returning to the description of FIG. 11A, the current command calculation unit 8 calculates the D-axis current command Id ^* and the Q-axis current command Iq ^* based on the magnetic flux command and the torque command. The torque command corresponds to, for example, a notch command transmitted from the cab, and the magnetic flux command can be set to a fixed value, for example. The voltage command calculation unit 9 determines the DQ axis output voltage commands Vd ^* and Vq ^* by, for example, PI control so that the fed back DQ axis current values Id and Iq follow the DQ axis current command. The voltage commands Vd ^* and Vq ^* are fundamental waves indicating target values obtained every predetermined period, and indicate an average value in a predetermined period. The coordinate conversion unit 10 converts the DQ axis output voltage commands Vd ^* , Vq ^* into modulation rate commands Au ^* , Av ^* , Aw ^* .

As shown in FIG. 11B, the coordinate conversion unit 10 includes a coordinate conversion circuit 10a and a modulation circuit 10b. The coordinate conversion circuit 10a calculates and outputs three-phase voltage commands Vu ^* , Vv ^* , Vw ^* based on the phase angle θdq of the DQ axis coordinate system from the DQ axis output voltage commands Vd ^* , Vq ^* . The modulation circuit 11a converts the three-phase voltage commands Vu ^* , Vv ^* , Vw ^* into modulation factors Au ^* , Av ^* , Aw ^* that indicate a ratio to the maximum output voltage (inverter input DC voltage). This modulation factor is a value obtained by dividing the inverter output voltage by the input DC voltage. Therefore, each modulation factor is a numerical value included in the range of 0-1. Based on these modulation factors, the gate generation unit 11 generates a gate signal corresponding to triangular wave comparison PWM, synchronous PWM, or one-pulse mode.

In this example, there is no means for directly detecting the rotational speed or position of the main motor 7. Instead, the speed estimation unit 13 estimates and calculates the rotational speed (that is, angular speed) of the main motor from the DQ axis voltage commands Vd ^* and Vq ^* and the DQ axis current values Id and Iq, and outputs an estimated angular speed ωrh. As a method for estimating the angular speed of the main motor 7 by the speed estimation unit 13, a method for obtaining the DQ axis voltage commands Vd ^* and Vq ^* and the calculation of the induced voltage based on the DQ axis current values Id and Iq, or DQ There are various conventional methods such as a method for obtaining the output voltage of the main motor 7 based on the shaft voltage commands Vd ^* and Vq ^* and the DQ shaft current values Id and Iq.

The slip frequency reference calculation unit 15 calculates and outputs a slip angular frequency reference ωs ^* (= secondary resistance R2 / secondary inductance L2 × Iq ^* / Id ^* ) based on the DQ axis current command.

The adder 16 adds the estimated angular velocity ωrh and the slip angular frequency reference ωs ^* to obtain an inverter output frequency ω1. This is integrated by the integrator 14 to determine the phase angle θdq of the DQ axis coordinate system with respect to the stationary coordinate system. This phase angle θdq has a large error in the initial stage of operation, but converges to a true value when speed estimation is performed by the speed estimation unit 13 during operation.

  The position / speed sensorless control device configured as described above can control the torque of the main motor. The above control system is assumed to be realized by the first control interrupt processing unit 30 that performs arithmetic processing by the first control interrupt.

The actual inverter output voltage waveform is not an ideal sine wave corresponding to the voltage commands Vd ^* and Vq ^* but a pulse-like waveform containing many high-frequency components. Therefore, the current detection values Id and Iq are also pulsed and have a waveform containing a lot of high-frequency components. In general, an estimation error is always included in the estimated angular velocity ωrh estimated using the voltage commands Vd ^* and Vq ^* indicating the target average value and the detected values Id and Iq of the current actually flowing in the motor. Yes. Therefore, a large ripple is superimposed on the estimated angular velocity ωrh.

  For this reason, if the estimation gain of the speed estimation unit 13 is set high in order to increase the estimation speed, the ripple further increases and a higher-order unstable phenomenon occurs. For this reason, increasing the estimated gain is limited. As a result, the responsiveness of the torque to the torque command and the suppression characteristic against the disturbance are deteriorated, and the control system is likely to be unstable. In some cases, resonance occurs between the reactor 3 and the capacitor 4 of the main circuit, or a sudden change in the DC voltage cannot be suppressed due to a sudden load change, and the overvoltage protection operates.

  Accordingly, an object of the present invention is to provide a position / speed sensorless control device with good responsiveness by reducing the estimation error in the speed estimation unit 13 and increasing the estimation gain.

A position / speed sensorless control apparatus according to an embodiment of the present invention includes: an inverter that converts a DC voltage into an AC voltage and drives an AC motor; an output voltage command calculation unit that calculates an output voltage command to the inverter; A gate generating means for generating a gate signal based on an output voltage command, a detecting means for detecting a current flowing through the AC motor, and the average value of the inverter output voltage in each section of the first control interrupt having the first cycle A process for estimating the rotational speed of the AC motor based on the average voltage calculation means for calculating the average voltage, and the current value detected by the detection means and the section average voltage calculated by the average voltage calculation means, Speed estimation means for performing at the timing of the first control interrupt;
It comprises.

The block diagram which shows the structure of the position / speed sensorless control apparatus which concerns on 1st Example of this invention. The figure which shows the relationship between the carrier CAR, the U phase modulation factor Au ^* , and the U phase gate signal Gu in triangular wave PWM. The figure which shows the other relationship of carrier CAR, triangular phase PWM, U phase modulation factor Au ^* , and U phase gate signal Gu in triangular wave PWM. The figure which shows the structural example of the area average voltage calculating part. The figure which shows the other structural example of the area average voltage 17. FIG. The figure which shows the further another structural example of the area average voltage 17. FIG. The figure which shows the structure of 2nd Example of this invention. FIG. 8 is a detailed block diagram of the output level detection unit 26 of FIG. 7. The figure which shows the structure of 3rd Example of this invention. The figure which shows the example of a waveform of 3dP mode. The figure which shows the structure of the conventional position / speed sensorless control apparatus. FIG. 3 is an equivalent circuit diagram of the AC motor 7. The figure which shows the outline | summary of induction motor vector control.

  Embodiments of a position / speed sensorless control apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a position / speed sensorless control apparatus according to a first embodiment of the present invention. In this sensorless control device, the input signal to the speed estimation unit 13 is different from the conventional one.

Six gate signals (Gu, Gx, Gv, Gy, Gw, Gz) that are outputs of the gate generation unit 11 are input to the section average voltage calculation unit 17. The section average voltage calculation unit 17 estimates and calculates the average voltage of a predetermined section for each phase from the gate signal, and outputs it as three-phase section average voltages Vuh, Vvh, and Vwh. The coordinate converter 18 converts the average voltage into a value on the DQ axis and outputs it as DQ axis section average voltages Vdh and Vqh. The speed estimation unit 13 inputs this DQ axis section average voltage in place of the conventional DQ axis voltage commands Vd ^* and Vq ^* , and estimates and calculates the speed. When the main motor is not an induction motor but a permanent magnet synchronous motor, the speed estimation unit 13 estimates the rotor position in addition to the speed.

Here, the section average voltage will be described. FIG. 2 shows the relationship between the carrier CAR, the U-phase modulation rate Au ^* , and the U-phase gate signal Gu in triangular wave PWM. Here, the U-phase gate signal Gu represents the U-phase output voltage. As described above, functions such as the vector control / current control / speed estimation unit are performed by the first control interrupt processing unit 31 in the processing of the control microcomputer. The first control interrupt process is one task among a plurality of tasks executed by the control microcomputer.

  FIG. 2 shows the interrupt generation timing of the first control interrupt processing unit 31 on the horizontal axis. Here, the “interval average voltage” interval refers to a processing interval for performing the estimated speed calculation, that is, a time interval during which the first control interruption occurs.

In the case of FIG. 2, the first control interrupt coincides with or synchronizes with the peaks and valleys of the carrier. In this case, the DQ voltage commands Vd * and Vq * calculated by the voltage command calculation unit 9 at the timing of the first control interruption, or the modulation rates Au *, Av * and Aw * which are the outputs of the coordinate conversion unit 10 are The average voltage of each section is expressed. In this case, when performing the estimated speed calculation, the average value (average value of the gate signal Gu) in the voltage section actually output from the inverter matches the voltage command Au *. That is, the areas of the squares a, b, c, and d are equal to the areas of the squares e, f, g, and d. Therefore, the current detection values Id and Iq are values corresponding to the voltage command values Vd ^* and Vq ^* of the inverter. In this case, the estimation error (that is, speed ripple) of the speed estimation value estimated by the speed estimation unit 13 is small, and good estimation is possible.

  However, when the carrier dispersion control method for dispersing the carrier frequency in order to reduce the noise of the electric motor, or when the period of the first control interruption is set faster than twice the carrier frequency because the carrier frequency is low, as shown in FIG. Can't maintain a good relationship.

An example of this is shown in FIG. In FIG. 3, the first control interrupt is not synchronized with the carrier. For this reason, the output voltage command Au * calculated in the first control interrupt does not match the average voltage (average value of the gate signal Gu) in the first control interrupt section. That is, the areas of the squares a ′, b ′, c ′, and d ′ are different from the areas of the squares e ′, f ′, g ′, and d ′. Therefore, the current detection values Id and Iq do not correspond to the voltage command values Vd ^* and Vq ^* of the inverter. For this reason, an estimation error occurs in the speed estimation value estimated by the speed estimation unit 13 using the current detection values Id and Iq and the voltage command values Vd ^* and Vq ^* , and this error appears as a ripple of the estimated angular velocity. .

  Therefore, in this embodiment, a second control interrupt that is faster than the first control interrupt is set, the gate signal Gu is read at the timing of the second control interrupt, and the output voltage is estimated and calculated based on the gate signal Gu. .

  FIG. 4 shows a configuration example of the section average voltage calculator 17 that estimates and calculates the output voltage in this way.

  The section average voltage calculator 17 receives the gate signal and the DC voltage value on the inverter input side. The coefficient converter 20 receives the gate signal and outputs 0.5 when the level is high and −0.5 when the level is low. Multiplier 21 multiplies the input DC voltage, and integrator 22 integrates it. Up to this point, high-speed computation is required, and computation processing is performed by the second control interrupt processing unit 19 at the timing of the second control interrupt. The section average voltage reading unit 23 performs processing at the timing of the first control interrupt. For each processing, the section average voltage reading unit 23 reads the output of the integrator 22 and outputs a reset signal to clear the integrator. With this configuration, it is possible to calculate the section average voltages Vuh, Vvh, Vwh, that is, the actual inverter output voltage average value.

  The coordinate converter 18 converts the section average voltages Vuh, Vvh, and Vwh into dq axis section average voltages Vdh and Vqh based on the rotor phase angle θdq. As a result, the speed estimation unit 13 performs an estimation calculation based on the section average voltages Vdh and Vqh indicating the actual values and the current detection values Id and Iq. To decrease.

  In FIG. 1, a total of six inputs, such as Gx that is complementary to the gate signal Gu, are input as inputs to the section average voltage calculation unit 17. As described above, calculation can also be performed using information on each phase of Gu, Gv, and Gw, but the voltage in a section in which Gu and Gx are low, such as dead time, cannot be estimated correctly only with Gu. For this reason, when Gx is added together with Gu and both Gu and Gx are low, it is determined that the dead time period is in progress, and based on the polarities of the phase current values Iu, Iv, Iw detected by the phase current detector 6. It is sufficient to determine whether the output voltage is high level or low level. That is, if the direction of the phase current detector 6 from the inverter 5 to the main motor 7 is positive, both Gu and Gx are low, and if Iu is positive, the switching device of the lower arm is connected in antiparallel. Since current flows through the diode, it is determined that the output voltage is at a low level. If Iu is negative, it is determined that the output voltage is at a high level because current flows through the diode connected in reverse parallel to the switching element of the upper arm. Thereby, it is possible to obtain a more accurate section average voltage in consideration of the dead time.

Another embodiment of the section average voltage is shown in FIG. Compared to FIG. 4, the integrator 22 has no reset signal input. On the other hand, the section average voltage reading unit 23 stores the difference between the value read from the integrator 22 and the previously read value (Z ⁻¹ ) as the estimated output voltage. Even with this configuration, the actual section average voltage can be calculated.

  Another embodiment of the section average voltage is shown in FIG. In this case, the second control interrupt processing unit 19 does not have a multiplication unit with a DC voltage, and the integration value read from the integrator 22 is obtained by the multiplier 21 provided in the preceding stage of the section average voltage reading unit 23. Multiply by DC voltage. Even in this configuration, the section average voltage can be obtained.

  The second control interrupt unit 19 may require high-speed processing of several microseconds or less in order to directly read the gate signal. Furthermore, if accuracy is pursued, it becomes impossible to deal with software, and it is effective to implement a hardware configuration such as GA (gate array). In the case of the configuration of FIG. 4 or FIG. 5, the second control interrupt processing unit requires an AD converter that supports high-speed sampling and hardware, and the demand for hardware increases. Since the change in the order of several microseconds of the DC voltage is small, as shown in FIG. 6, the gate signal reading and integration are performed by the high-speed second control interruption process, and the DC voltage with a small change is multiplied. It is effective to implement the first control interrupt process.

  In an application example in which the fluctuation of the DC voltage is small, the DC voltage can be handled as a fixed value.

(Operational effect of the first embodiment)
By configuring as described above, it is possible to obtain the section average voltage that is the average voltage of the section in which the estimated angular velocity is calculated, and by using this, the estimation angular speed having a small estimation error can be obtained. Can do. As a result, the estimated gain can be increased without causing higher-order instability of the control system, so that the torque response and disturbance suppression characteristics are improved. As a result, it is possible to avoid a protection operation due to an unstable phenomenon of the control system or an overvoltage.

  Further, as described above, the output voltage command calculated by the first control interrupt unit may match the section average output voltage of the first control interrupt, but as shown in FIG. The expected output voltage cannot be obtained when the period of the interruption is smaller than ½ of the carrier period or when the period of the first control interruption is not an integral multiple of ½ of the carrier period. In this case, if a second control interrupt faster than the first control interrupt is provided, the gate signal is read, and the average output voltage of the first control interrupt interval is calculated, a highly accurate position / speed estimation can be performed. It becomes possible.

  Furthermore, as described above, the accuracy of the section average voltage greatly depends on the speed of the second control interrupt for reading the gate signal. For example, if the switching frequency is 5 kHz, the time of 1/2 cycle of the carrier is 100 μsec. If the period of the second control interrupt is 1 μsec, the detection resolution is 1% voltage. This is close to the control limit. Realizing this 1 μsec by software is difficult in terms of processing speed. As described above, by realizing the second control interrupt unit with hardware such as GA, a highly accurate section average voltage can be obtained.

  In this embodiment, a two-level inverter is assumed, but it is a well-known fact that the level of the output voltage can be determined from the gate signal even with a multi-level inverter.

  In addition, when estimating the output voltage from the gate signal, when considering the dead time period to improve the accuracy of the estimated voltage, it is well known that the output voltage level can be determined from each flowing phase current as described above. Is the fact of

  FIG. 7 shows the configuration of the second embodiment of the present invention. Compared with the first embodiment, since the input signal of the section average voltage calculation unit 17 is different, only this part will be described.

  The output level detection unit 26 receives the output potential of each phase and detects whether it is a high level output or a low level output. A detailed block diagram is shown in FIG.

  The output level detection unit 26 includes an output level detection circuit 27 for each phase. For example, the U-phase output point and the negative potential point on the DC side are divided by resistors R1 and R2, insulated by a photocoupler (PH), etc., and taken into the control system, so that a high level is actually output. Or whether a low level is output. The subsequent processing method is the same as in the first embodiment. In this embodiment, a two-level inverter is assumed, but it is obvious that the level of the output voltage of the inverter can be determined according to this embodiment even in the case of a multi-level inverter.

(Operational effect of the second embodiment)
According to the present embodiment, it is possible to determine the output level directly from the actual output voltage as compared with the first embodiment. When the output voltage is predicted from the gate signal as in the first embodiment, there are error factors such as a delay from the rise of the gate signal to the actual rise of the output voltage and a compensation error of dead time. In addition, by making a determination from the direct output, it is possible to calculate the section average voltage with high accuracy by eliminating these error factors.

  FIG. 9 shows the configuration of the third embodiment of the present invention. Compared to the first embodiment, the information input to the section average voltage calculation unit 17 is not gate information but a three-phase voltage command (strictly, a three-phase modulation factor command). Only the different parts will be described below.

  The section average voltage calculation unit 17 inputs voltage commands for each phase, that is, modulation rate commands Au *, Av *, and Aw *. For example, in the synchronous PWM method, switching is performed based on the output voltage phase information and its modulation factor command.

  For example, the case of 3dP (3-dash pulse mode) will be described with the waveform example of FIG. In the case of 3 dP as shown in FIG. 10, switching is performed in the vicinity of 0 degree and 180 degrees according to the phase angle of the U-phase output voltage. In the case of such a synchronous PWM method, the average value of the output voltage actually output in the section of the first control interrupt does not match the output voltage command calculated by the first control interrupt.

  Here, the relationship between the firing angle α [rad] and the modulation factor is as follows.

Modulation rate Au ^* [PU] = 2 × cos (α) −1
This PU (par unit) indicates that there is no unit with a normalized value of Au ^* .

  Therefore, the firing angle α [rad] may be obtained as follows.

Firing angle α [rad] = Acos ((Au ^* + 1) / 2)
In addition, what is necessary is just to obtain | require the output voltage phase angle of each phase as follows.

θu = θdq + Atan (Vq ^* / Vd ^* )
θv = θdq + Atan (Vq ^* / Vd ^* ) − 2 × π / 3
θw = θdq + Atan (Vq ^* / Vd ^* ) + 2 × π / 3
Thus, the first control interrupt unit can accurately grasp what gate signal is output based on the information on the output voltage phase angle and the modulation rate command at that time. That is, the section average voltage calculation unit 17 can grasp the waveform of the gate signal Gu shown in FIG. Therefore, it is possible to calculate the integral value from this gate signal (in this case, expressed by a signal of 1 / −1).

  In the case of the 3-dash pulse in FIG. 10, the section average voltage can be obtained as follows.

As described above, in the case of the 3-dash pulse, the phase to be ignited (ignition angle θ) is obvious from the above equation. For example, in the case of the U phase, the current U-phase output voltage phase angle is θu1, and the previous phase If the angle is θu2, the U-phase section average voltage can be calculated as in the following equation. However, Gu3dP (θ) in the following equation is 1 if the actual U-phase output voltage is a positive potential output with respect to the gate signal selected for the firing angle θ in the U-phase 3-dash pulse. Is a function that outputs -1 if the potential output is negative. That is, Gu3dP (θ) takes a value of 1 or -1.

(Operational effect of the third embodiment)
By configuring as described above, it is possible to calculate the section average voltage even in the synchronous PWM control. In the present embodiment, since the section average voltage can be obtained without using the second control interruption process, there is an advantage that can be realized without providing a software load of the control microcomputer or special hardware.

  In this embodiment, the control configuration diagram is for an induction motor, but the present invention can be similarly applied to other motors.

The above description is an embodiment of the present invention, and does not limit the apparatus and method of the present invention, and various modifications can be easily implemented. For example, various inventions can be configured by appropriately combining a plurality of constituent elements disclosed in the embodiment.
The invention described in the scope of the claims at the beginning of the present application is added below.
[1]
An inverter that converts a DC voltage into an AC voltage and drives an AC motor;
Output voltage command calculating means for calculating an output voltage command to the inverter;
Gate generating means for generating a gate signal based on the output voltage command;
Detecting means for detecting a current flowing through the AC motor;
Average voltage calculation means for calculating the inverter output voltage average value in each section of the first control interrupt having the first cycle as the section average voltage;
Based on the current value detected by the detection means and the section average voltage calculated by the average voltage calculation means, the speed estimation is performed at the timing of the first control interrupt based on the process of estimating the rotational speed of the AC motor. Means,
A position / speed sensorless control apparatus comprising:
[2]
The average voltage calculating means calculates the section average voltage based on the gate signal and the DC voltage value, according to [1].
[3]
The section average voltage calculation means reads a gate signal at a cycle shorter than the first control interrupt, integrates the gate signal in each section of the first control interrupt processing, and obtains the section average voltage. The control device according to [2].
[4]
The gate generating means is means for generating a gate signal by triangular wave comparison PWM,
The control device according to any one of [1] to [3], wherein the interrupt cycle of the first control interrupt is set to a cycle shorter than a half cycle of the triangular wave carrier.
[5]
The gate generating means is means for generating a gate signal by triangular wave comparison PWM,
The control apparatus according to any one of [1] to [3], wherein the interrupt period of the first control interrupt is set to a period other than an integral multiple of a half period of the triangular wave carrier.
[6]
The inverter is an N-level output converter,
The average voltage calculation means determines whether the output voltage of the inverter is output at the N level, and obtains the section average voltage based on the output level and the DC voltage. 1] The control device according to the above.
[7]
The section average voltage calculation means reads the output voltage level of the inverter at a cycle shorter than the first control interrupt, integrates the output voltage level in each section of the first control interrupt, and calculates the section average voltage. The control device according to [6], wherein the control device is obtained.
[8]
The control device according to [1], wherein the gate generation unit generates a gate signal by a synchronous PWM method.

  DESCRIPTION OF SYMBOLS 1 ... Pantograph, 2 ... Wheel, 3 ... Reactor, 4 ... Capacitor, 5 ... VVVF inverter, 6 ... Phase current detector, 7 ... Main motor.

Claims (6)

An inverter that converts a DC voltage into an AC voltage and drives an AC motor;
Output voltage command calculating means for calculating an output voltage command to the inverter;
Gate generating means for generating a gate signal based on the output voltage command;
Detecting means for detecting a current flowing through the AC motor;
An average voltage calculation means for calculating an output voltage mean value of the inverter in each section of the first control interrupt having a first period as a section average voltage,
Speed at which the process of estimating the rotational speed of the AC motor is performed at the timing of the first control interrupt based on the current value detected by the detection means and the section average voltage calculated by the average voltage calculation means An estimation means ,
The gate generating means is means for generating a gate signal by triangular wave comparison PWM,
The first cycle of the first control interrupt is set to a cycle shorter than a half cycle of a triangular wave carrier;
A position / speed sensorless control device characterized by that.   An inverter that converts a DC voltage into an AC voltage and drives an AC motor;
  Output voltage command calculating means for calculating an output voltage command to the inverter;
  Gate generating means for generating a gate signal based on the output voltage command;
  Detecting means for detecting a current flowing through the AC motor;
  Average voltage calculation means for calculating an average output voltage value of the inverter in each section of the first control interrupt having the first cycle as a section average voltage;
  Speed at which the process of estimating the rotational speed of the AC motor is performed at the timing of the first control interrupt based on the current value detected by the detection means and the section average voltage calculated by the average voltage calculation means An estimation means,
  The gate generating means is means for generating a gate signal by triangular wave comparison PWM,
  The first period of the first control interrupt is set to a period other than an integral multiple of a half period of a triangular wave carrier;
A position / speed sensorless control device characterized by that. The control device according to claim 1 or 2 , wherein the average voltage calculation means calculates the section average voltage based on the gate signal and a DC voltage value input to the inverter . Before Kitaira average voltage calculation means, the read gate signal at a short period from the first period of the first control interrupt, the interval average by integrating the gate signal at each interval of the first control interrupt The control device according to claim 3 , wherein a voltage is obtained. The inverter is an N-level output converter,
It said average voltage calculating means, wherein the output voltage of the inverter is the determining whether the output at any level of the N levels, and obtains the interval average voltage on the basis of the level and the DC voltage Item 3. The control device according to Item 1 or 2 . Before Kitaira average voltage calculation unit reads the output voltage level of said inverter in a shorter period than the first period of the first control interrupt, integrating said output voltage level in each section of the first control interrupt The control device according to claim 5, wherein the section average voltage is obtained.

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