JP6477147B2 - Method for measuring the amount of flux linkage in a permanent magnet motor, program for measuring the amount of flux linkage in a permanent magnet motor, and device for measuring the amount of flux linkage in a permanent magnet motor - Google Patents

Description

  The present invention relates to a method for measuring the amount of magnetic flux linkage of a permanent magnet motor, a program for measuring the amount of magnetic flux linkage of a permanent magnet motor, and the magnetic flux linkage of a permanent magnet motor. The present invention relates to a quantity measuring device.

  Conventionally, when controlling a permanent magnet synchronous motor, control is performed using motor constants such as d-axis inductance, q-axis inductance, winding resistance value, and flux linkage of the permanent magnet motor. The high measurement accuracy of these motor constants affects the accuracy of motor control. For this reason, for example, Patent Document 1 describes a technique for measuring d-axis inductance and q-axis inductance.

  By the way, among the motor constants, the amount of flux linkage of the permanent magnet motor is obtained by dividing the induced voltage by the rotational speed of the rotor. Therefore, in order to measure the flux linkage with high accuracy, it is necessary to measure the induced voltage and the rotational speed of the rotor with high accuracy.

JP 2008-086129 A

  In the conventional measurement of the interphase induced voltage, there is a method of observing the terminal voltage of the measured motor by rotating the rotor of the motor from the outside without energizing the motor. A device for supplying an external force that directly rotates the shaft is required. Further, when the rotating shaft of the rotor is not exposed to the outside of the housing as in a compressor motor, the rotor cannot be rotated by an external force.

  In addition, when the rotating shaft of the rotor is not exposed to the outside of the housing, after rotating the electric motor with an inverter, rotating it as a free-run state, and observing the interphase induced voltage during rotation in inertia, the rotor Since it decelerates, the amount of flux linkage of the permanent magnet motor cannot be measured accurately.

  The present invention has been made in view of the above, and the amount of interlinkage magnetic flux of a permanent magnet motor that can accurately measure the amount of interlinkage magnetic flux of a permanent magnet motor even when the rotor rotates due to inertia. It is an object of the present invention to provide a measuring method, a flux linkage measuring program for a permanent magnet motor, and a flux linkage measuring device for a permanent magnet motor.

  In order to solve the above-described problems and achieve the object, a method for measuring the amount of flux linkage in a permanent magnet motor according to the present invention is the amount of flux linkage in a permanent magnet motor that measures the amount of flux linkage in a permanent magnet motor. A measuring method, wherein the permanent magnet rotor is shifted to a free-run state by stopping the power supply to the permanent magnet motor from a state where the permanent magnet rotor is rotating. An induced voltage measurement step for obtaining the rotation speed and measuring the induced voltage of the motor at a predetermined sampling period from the time when the power supply is stopped, and determining the amount of attenuation by assuming that the time change of the measured induced voltage is exponential decay And a time-series sampling corresponding to the reduction of the rotational speed of the permanent magnet rotor based on the attenuation exponent function having the attenuation amount. A correction step for obtaining a correction sampling time point for correcting the time point, further calculating a correction induced voltage and a correction rotation angle at the correction sampling time point, a correction induced voltage amplitude value calculation step for calculating an amplitude value of the correction induced voltage, A linkage magnetic flux amount calculating step of calculating a value obtained by dividing the amplitude value of the correction induced voltage by the rotation speed value at the start of the free-run state as the linkage magnetic flux amount of the permanent magnet motor.

  A method of measuring the amount of flux linkage of a permanent magnet motor according to the present invention is the method of measuring the amount of flux linkage of a permanent magnet motor that measures the amount of flux linkage in the permanent magnet motor in the above invention. While acquiring the rotational speed of the permanent magnet rotor at the time of stopping the power supply to shift the permanent magnet rotor to the free-run state by stopping the power supply to the permanent magnet motor from the state where the magnet rotor is rotating An induced voltage measurement step for measuring the induced voltage of the electric motor at a predetermined sampling period from the time when the power supply is stopped, and an attenuation coefficient of an exponent part for determining a time variation of the measured induced voltage as an exponential decay. Optimum attenuation when the correlation value obtained by the correlation processing obtained by multiplying the induced voltage by the trigonometric function obtained by multiplying the attenuation exponential function with the variable as the variable is the maximum An optimum damping coefficient determining step for determining the number, and a corrected sampling time point obtained by correcting a time-series sampling time corresponding to a reduction in the rotational speed of the permanent magnet rotor based on the optimum damping index function having the optimum damping coefficient And a correction step for calculating a correction induced voltage and a correction rotation angle at the time of the correction sampling, and a correlation obtained by a correlation process obtained by multiplying the fundamental wave trigonometric function having the correction rotation angle as a variable by the correction induction voltage. A corrected induced voltage amplitude value calculating step for calculating a corrected induced voltage amplitude value of a fundamental wave component based on the value; and a value obtained by dividing the corrected induced voltage amplitude value by a rotation speed at the start of a free-run state. An interlinkage magnetic flux amount calculating step for calculating the interlinkage magnetic flux amount.

  Further, the interlinkage magnetic flux amount measuring method for a permanent magnet motor according to the present invention is the above invention, wherein in the optimum damping coefficient determination step and the corrected induced voltage amplitude value calculation step, an interphase value and a cosine wave using a sine wave are used. The square root of the sum of squares for the interphase value using is used.

  A program for measuring the amount of flux linkage in a permanent magnet motor according to the present invention is a program for measuring the amount of flux linkage in a permanent magnet motor for measuring the amount of flux linkage in a permanent magnet motor. Obtaining the rotational speed of the permanent magnet rotor at the time of stopping the power supply for shifting the permanent magnet rotor to the free-run state by stopping the power supply to the permanent magnet motor from the state where the rotor is rotating An induced voltage measuring step for measuring the induced voltage of the electric motor at a predetermined sampling period from the time of supply stop, an attenuation amount determining step for determining the attenuation amount with the time change of the measured induced voltage as exponential decay, and Based on a damping index function having a damping amount, the time series sampling time points corresponding to the reduction of the rotational speed of the permanent magnet rotor were corrected. A correction step for obtaining a positive sampling time point, calculating a correction induced voltage and a correction rotation angle at the correction sampling time point, a correction induced voltage amplitude value calculating step for calculating an amplitude value of the correction induced voltage, and a correction induced voltage A linkage magnetic flux amount calculating step of calculating a value obtained by dividing the amplitude value by the rotation speed value at the start of the free-run state as the linkage magnetic flux amount of the permanent magnet motor is executed.

  The apparatus for measuring the amount of flux linkage in a permanent magnet motor according to the present invention is a device for measuring the amount of flux linkage in a permanent magnet motor for measuring the amount of flux linkage in a permanent magnet motor, wherein the permanent magnet rotor rotates. The rotation speed of the permanent magnet rotor at the time of stopping the power supply for shifting the permanent magnet rotor to the free-run state by stopping the power supply to the permanent magnet motor from the state where the power supply is stopped and from the time of stopping the power supply An induced voltage measuring unit that measures the induced voltage of the motor at a predetermined sampling period; an attenuation determining unit that determines the amount of attenuation of the measured induced voltage over time as exponential attenuation; and the attenuation amount. A corrected sampling time point obtained by correcting a time-series sampling time point corresponding to the reduction of the rotation speed of the permanent magnet rotor based on the damping index function obtained; A correction unit that calculates a correction induced voltage and a correction rotation angle at the time of correction sampling, a correction induced voltage amplitude value calculation unit that calculates an amplitude value of the correction induced voltage, and an amplitude value of the correction induced voltage at the start of a free-run state A flux linkage amount calculation unit that calculates a value obtained by dividing the rotation speed value as a flux linkage amount of the permanent magnet motor.

  According to the present invention, the rotation of the permanent magnet rotor at the time of stopping the power supply in which the permanent magnet rotor is shifted to the free run state by stopping the power supply to the permanent magnet motor from the state in which the permanent magnet rotor is rotating. The speed is acquired and the induced voltage of the motor is measured at a predetermined sampling period from the time when the power supply is stopped, the time variation of the measured induced voltage is determined as exponential decay, and the amount of decay is determined. A correction sampling time point obtained by correcting a time series sampling time point corresponding to the deceleration of the rotation speed of the permanent magnet rotor is obtained based on the attenuation exponent function, and a correction induced voltage and a correction rotation angle at the correction sampling time point are obtained. Calculating the amplitude value of the corrected induced voltage, and calculating the amplitude value of the corrected induced voltage as the rotational speed at the start of a free-run state. In that the dividing value calculated as the flux linkage amount of the permanent magnet motor. Thereby, even when the rotor rotates due to inertia and decelerates due to the influence of friction or rotational load, the amount of magnetic flux linkage of the permanent magnet motor can be measured with high accuracy.

FIG. 1 is a block diagram showing a configuration including a flux linkage measuring device for a permanent magnet motor according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the positional relationship between the permanent magnet rotor and each phase coil in the electric motor shown in FIG. FIG. 3 is a diagram illustrating an example of a time waveform of the interphase induced voltage measured by the interphase induced voltage measurement unit in the interlinkage magnetic flux amount measuring device of the permanent magnet motor. FIG. 4 is a diagram illustrating the relationship between the damping index function, the sine damping function, and the cosine damping function. FIG. 5 is a diagram illustrating an example of a change in the magnitude of the overall correlation value when the attenuation coefficient of the attenuation exponent function is changed. FIG. 6 is a diagram illustrating the relationship between the corrected interphase induced voltage and the trigonometric function of the fundamental wave having the magnitude and phase of the overall correlation value. FIG. 7 is a flowchart showing a procedure for measuring the amount of flux linkage of the permanent magnet motor by the amount of flux linkage measuring device for the permanent magnet motor.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

(overall structure)
FIG. 1 is a block diagram showing a configuration including an interlinkage magnetic flux amount measuring device 10 (hereinafter referred to as an interlinkage magnetic flux amount measuring device 10) of a permanent magnet motor according to an embodiment of the present invention. In FIG. 1, an interlinkage magnetic flux amount measuring device 10 measures the amount of interlinkage magnetic flux in a permanent magnet motor MO (hereinafter referred to as “motor MO”) that is driven and controlled by the motor control device 1.

(Permanent magnet motor)
As shown in FIG. 2, the permanent magnet motor MO has a U-phase coil 31, a V-phase coil 32, and a W-phase coil 33 around which windings of U-phase, V-phase, and W-phase are wound. A permanent magnet synchronous motor in which a permanent magnet rotor (hereinafter referred to as a rotor) 30 rotates when an AC voltage is applied to the windings of the phase coils 31 to 33. Preferably, it is a permanent magnet embedded type electric motor. The drive unit 3 drives the rotor 30 by supplying an AC voltage whose phase is shifted by 120 ° in electrical angle to the phase coils 31 to 33.

(Motor control device)
As shown in FIG. 1, the electric motor control device 1 includes a voltage command generation unit 2 including a non-interacting control unit 6, a drive unit 3, a current detection unit 4, and a phase / angular velocity detection unit 5. The current detection unit 4 detects the amplitude of at least two-phase currents. For example, the current detection unit 4 includes a current sensor 41 that detects the amplitude of the U-phase current iu and a current sensor 42 that detects the amplitude of the V-phase current iv.

  The phase / angular velocity detector 5 calculates a W-phase current iw from the current iu and the current iv, and has a fixed coordinate system (UVW coordinate system) obtained from the current iw and the detected current iu and current iv. The current vector (iu, iv, iw) is converted into a current vector (Id, Iq) in the rotating coordinate system (dq coordinate system). Then, the phase / angular velocity detector 5 outputs the current Id, the current Iq, the electrical angle θe (rad) of the rotor 30, and the mechanical angular velocity ωm (rad / s) to the voltage command generator 2. The electrical angle θe is output to the drive unit 3, and the electrical angular angular velocity ωe is output to the interlinkage magnetic flux amount measuring device 10. The mechanical angular velocity ωm is obtained by dividing the electrical angular angular velocity ωe by the pole pair number Pn of the motor MO, and the electrical angular angular velocity ωe obtained at this time is output to the flux linkage measuring device 10. The phase / angular velocity detector 5 may output the mechanical angular velocity ωm instead of the electrical angular velocity ωe to the flux linkage measuring device 10. In this case, the flux linkage measuring apparatus 10 can obtain the electrical angular angular velocity ωe by multiplying the input mechanical angular angular velocity ωm by the number of pole pairs Pn. The pole pair number Pn is stored in advance in a storage unit (not shown) as a constant. Incidentally, in the present embodiment, the permanent magnet motor MO is controlled by so-called vector control, but the present invention is not limited to this. That is, as will be described below, any control may be used as long as the rotor 30 can be shifted from the state rotated at a predetermined rotational speed to the free-run state.

  The voltage command generator 2 receives a d-axis current command value Ido * and a mechanical angular velocity command ωm * from an upper controller (not shown), and receives the input current Id, current Iq, electrical angle θe, and mechanical angular velocity ωm. And a d-axis voltage command value Vd * and a q-axis voltage command value Vq * are generated in accordance with the mechanical angular velocity command ωm * and output to the drive unit 3. The d-axis voltage command value Vd * and the q-axis voltage command value Vq * are also output to the phase / angular velocity detection unit 5, and the phase / angular velocity detection unit 5 receives the d-axis voltage command value Vd * and the q-axis voltage command. Based on the value Vq *, the current Id, and the current Iq, an axial error Δθ that is a deviation between the actual position of the rotor 30 and the calculated position is obtained, and the above-described electrical error is obtained based on the axial error Δθ. The angular angular velocity ωe is calculated. The phase / angular velocity detector 5 outputs a mechanical angular velocity ωm obtained by dividing the electrical angular angular velocity ωe by the pole pair number Pn, and outputs an electrical angle θe obtained by integrating the electrical angular angular velocity ωe.

  The non-interacting control unit 6 prevents the interference between the d-axis voltage command value Vd * and the q-axis voltage command value Vq *, based on the electrical angular angular velocity ωe, current Id, and current Iq. Each correction value of the value Vd * and the q-axis voltage command value Vq * is output. The decoupling control unit 6 uses the d-axis inductance, the q-axis inductance, the winding resistance value, the interlinkage magnetic flux amount of the motor MO, and the like, which are the motor constants of the motor MO obtained in advance, and the driving voltage of the motor MO. Correct. The interlinkage magnetic flux amount measuring device 10 described above is a device for measuring in advance the interlinkage magnetic flux amount of the motor MO. When measuring the amount of flux linkage, the motor MO is driven by substituting an appropriate magnetic flux value for the non-interacting measuring unit 6. The interlinkage magnetic flux measuring device 10 is preferably connected to the motor control device 1 only when measuring the amount of interlinkage magnetic flux of the motor MO.

  The drive unit 3 is based on the d-axis voltage command value Vd * and the q-axis voltage command value Vq * input from the voltage command generation unit 2 and the electrical angle θe input from the phase / angular velocity detection unit 5. Three-phase U-phase voltage command value Vu *, V-phase voltage command value Vv *, and W-phase voltage command value Vw * are generated. Based on the generated U-phase voltage command value Vu *, V-phase voltage command value Vv *, and W-phase voltage command value Vw *, the drive unit 3 converts the external DC voltage Vdc input from the outside into a three-phase AC. The voltage is converted into a U-phase voltage, a V-phase voltage, and a W-phase voltage, which are supplied to the phase coils 31 to 33 of the electric motor MO.

(Configuration of flux linkage measuring device)
As shown in FIG. 1, the interlinkage magnetic flux amount measuring device 10 receives an electrical angular angular velocity ωe and a power supply stop signal SG from the motor control device 1, and is detected by the voltage detection sensor 21 from the voltage detection unit 20. The U phase voltage Vu and the V phase voltage Vv detected by the voltage detection sensor 22 are input.

  The flux linkage measuring device 10 includes a control unit CT, an input / output unit 16, and a storage unit 17. Further, the control unit CT includes an induced voltage measurement unit 11, an attenuation amount determination unit 12, a correction unit 13, a correction induced voltage amplitude value calculation unit 14, and an interlinkage magnetic flux amount calculation unit 15.

The interphase induced voltage between the phases of the U-phase coil 31, V-phase coil 32, and W-phase coil 33 (between the motor terminals) is the amount of interlinkage magnetic flux of the motor MO (the amount of magnetic flux interlinking with the coils of each phase). This is a time change, and is the product of the amount of flux linkage of the motor MO and the angular velocity of the rotor 30. Therefore, as shown in the equation (1), the flux linkage amount ψe of the motor MO can be obtained as a value obtained by dividing the amplitude value Euv of the induced voltage by the electrical angular angular velocity ωe. Here, the amount of flux linkage Ψe is the amount of flux linkage at the electrical angular angular velocity.
Ψe = Euv / ωe (1)
However, the control by the electric motor control device 1 performs control using a rotating coordinate system (dq coordinate system), and in this rotating coordinate system, the effective value (Ψe / 2 ^ (1/2)) of the flux linkage amount Ψe. The effective flux linkage amount Ψre is used. This interlinkage effective flux Ψre is obtained by setting the interphase peak voltage Euv as the interphase voltage effective value Eruv. That is, the flux linkage effective amount Ψre is obtained by the equation (2).
Ψre = Eruv / ωe (2)

  First, the induced voltage measurement unit 11 stops the power supply to the motor MO from the state where the rotor 30 in the motor MO is rotating at a constant rotational speed N, and causes the rotor 30 to shift to the free-run state. The electrical angular angular velocity ωe at the time of receiving the stop signal SG is acquired, and the interphase induced voltage between the motor terminals (coils 31 to 33) from the time of receiving the power supply stop signal SG, for example, the U-phase coil 31 and the V-phase coil 32 The interphase induced voltage Vuv is measured at a predetermined sampling period Ts.

  The free-run state is a state in which the electric motor controller 1 side is set to a high impedance state without supplying current from the drive unit 3 to the electric motor MO side, and the rotor 30 is rotated by inertia. Accordingly, the rotor 30 is decelerated due to friction and load in the free-run state.

  The interphase induced voltage Vuv is obtained by subtracting the V-phase voltage Vv detected by the voltage detection sensor 22 from the U-phase voltage Vu detected by the voltage detection sensor 21. Instead of the interphase induced voltage Vuv, the interphase induced voltages Vvw and Vwu may be used.

In the sampling of the interphase induced voltage Vuv, the sampling cycle Ts can be varied by instructing the interlinkage magnetic flux measuring device 10 the sampling number m and the cycle number C to be measured. This sampling period Ts is obtained by the following equation (3).
Ts = (Pn × C) / N × (1 / m) (3)
In actual measurement, since the rotor 30 decelerates while the rotor 30 is in a free-run state, the data has a cycle shorter than the instructed cycle number C.

  FIG. 3 is a diagram illustrating a time waveform of the interphase induced voltage Vuv measured by the induced voltage measurement unit 11. The plot indicated by ● in FIG. 3 is the interphase induced voltage Vuv at the time of sampling, and the solid line is a value obtained by linearly interpolating each plot. The total number of sampling is m. t (n) indicates the nth sampling time point. As shown in FIG. 3, the interphase induced voltage Vuv decelerates by friction and load from the time t (0) when the free run state is reached, and the peak value also decreases.

  The attenuation amount determination unit 12 assumes that the time change of the measured interphase induced voltage Vuv is exponential attenuation, and multiplies the attenuation exponent function η (n) with the attenuation coefficient α that determines the attenuation amount as a variable. The optimum attenuation coefficient αmax when the correlation value obtained by the correlation processing multiplied by the interphase induced voltage Vuv (n) is maximized is determined.

First, the attenuation amount determination unit 12 uses the attenuation exponent function η (n) as a normalized attenuation function with respect to time, and uses the attenuation coefficient α of the exponent part as a variable for determining the attenuation amount of the exponent function as the following equation (4): Define.
η (n) = exp {−α × t (n)} (4)
As described above, n is 0 to m-1.

Further, the electrical angular angular velocity ωe (n) at each sampling time point n corresponds to the attenuation exponent function η (n) with respect to the electrical angular angular velocity ωe (0) at the start t (0) of the free-run state. As shown in (5), the electrical angular angular velocity ωeη (n) is defined as one that attenuates.
ωeη (n) = η (n) × ωe (0) (5)

The electrical angular difference Δθ (at the sampling interval time (t (n) −t (n−1)) is obtained by multiplying the electrical angular angular velocity ωeη (n) by the sampling interval time (t (n) −t (n−1)). n) is expressed by the following equation (6). Further, the rotation angle θ (n) of the permanent magnet rotor 30 at each sampling time t (n) can be expressed by the following equation (7). Here, the rotation angle θ (n) is an electrical angle.
Δθ (n) = {t (n) −t (n−1)} × ωeη (n) (6)
θ (n) = θ (n−1) + Δθ (n) (7)

Then, as shown in the following equations (8) and (9), a sine attenuation that is a sine component of a trigonometric function multiplied by the attenuation exponential function η (n) using the rotation angle θ (n) of the equation (7). A function Sη (n) and a cosine decay function Cη (n) which is a cosine component are generated.
Sη (n) = η (n) × sin {θ (n)} [0 ≦ θ (n) ≦ 2kπ]
Sη (n) = 0 [θ (n)> 2kπ] (8)
Cη (n) = η (n) × cos {θ (n)} [0 ≦ θ (n) ≦ 2kπ]
Cη (n) = 0 [θ (n)> 2kπ] (9)
However, k is the number of electrical angular cycles, and is the number of cycles not exceeding the sampling number m. FIG. 4 is a diagram showing the relationship between the attenuation exponent function η (n) and the generated sine attenuation function Sη (n) and cosine attenuation function Cη (n).

Further, as shown in equations (10) and (11), correlation processing between the measured correlation induced voltage Vuv (n) and the sine attenuation function Sη (n), and the correlation induced voltage Vuv and the cosine attenuation function Cη (n) And correlation values Esin and Ecos are obtained.

  Here, in general, the value of the correlation processing obtained by multiplying the function by the function indicates the similarity between the two functions. For example, if the multiplication value of two functions is large, the two functions are similar, and if the multiplication value of the two functions is small, the two functions are not very similar. In particular, when the multiplication value of two functions is 0, it is an orthogonal relationship and can be said to be irrelevant.

Then, the following equation using the correlation value Esin between the interphase induced voltage Vuv (n) and the sine decay function Sη (n) and the correlation value Ecos between the interphase induced voltage Vuv (n) and the cosine decay function Cη (n): From (12) and (13), the magnitude | Euv | and the phase φ of the overall correlation value Euv are obtained. The magnitude | Euv | (amplitude) and the phase φ of the overall correlation value Euv mean the amplitude | Euv | and the phase φ of the trigonometric function between them. The magnitude | Euv | of the overall correlation value Euv is a square root value of the square sum of the correlation value Esin and the correlation value Ecos.

  Note that (1 / kπ) in the equations (10) and (11) is a coefficient for adjusting the degree of coincidence of correlation values, similarly to the Fourier coefficient. The magnitude | Eruv | of the overall correlation value Eruv obtained from the two expressions (10) and (11) is the square root of the square sum of the correlation value Esin and the correlation value Ecos, as shown in the expression (12). It is obtained as an effective value (| Euv | / 2 ^ (1/2)). Further, the phase φ of the overall correlation value Eruv is obtained as arctan which is a value obtained by dividing the correlation value Esin by the correlation value Ecos as shown in the equation (13).

  By the way, the attenuation coefficient α of the above-described attenuation index function η (n) is a variable. Therefore, when the value of the variable is changed to obtain the change in the value of the above-described overall correlation value Eruv | Eruv |, the change is as shown in FIG. 5 and the magnitude of the overall correlation value Eruv | The optimum value (optimum attenuation coefficient) αmax of the attenuation coefficient α is as follows. In FIG. 5, the optimum attenuation coefficient αmax exists between the attenuation coefficient α of 2 to 3. For example, the optimum attenuation coefficient αmax is 2.5. When the attenuation coefficient α is in the vicinity of the maximum value, there is little change in the value of the attenuation coefficient α. Therefore, in order to avoid erroneous detection due to noise, the attenuation coefficient α is a moving average value. It can be said that the attenuation index function η (n) when the attenuation coefficient α is the optimum attenuation coefficient αmax is most correlated with the time change of the correlation induced voltage Vuv. In this way, the attenuation amount determination unit 12 determines the optimum attenuation coefficient αmax.

  Next, the correction unit 13 uses the optimum attenuation exponent function ηα (n) having the optimum attenuation coefficient αmax, and sets the measured correlation induced voltage Vuv so that there is no deceleration of the rotor 30 after the free-run state. Corrected sampling in which the time series sampling time point t (n) corresponding to the deceleration of the electrical angular angular velocity ωe of the rotor 30 is corrected to a state in which the rotor 30 does not decelerate in order to perform inverse conversion to return to the correlation induced voltage Vuv. The time t ′ (n) is obtained, and the corrected interphase induced voltage Vuv ′ (n) and the corrected rotation angle θ ′ (n) at the corrected sampling time t ′ (n) are calculated.

The corrected sampling time t ′ (n) can be expressed by the following equation (14).
t ′ (n) = t ′ (n−1) + {t (n) −t (n−1)} × ηα (n)
... (14)
Further, the corrected interphase induced voltage Vuv ′ (n) can be expressed by the following equation (15).
Vuv ′ (n) = Vuv (n) / ηα (n) (15)
Furthermore, the corrected electrical angle difference Δθ ′ (n) in the corrected sampling time interval (t ′ (n) −t ′ (n−1)) can be expressed by the following equation (16).
Δθ ′ (n) = ωe × {(t ′ (n) −t ′ (n−1))} (16)
Further, the corrected rotation angle θ ′ (n) at the corrected sampling time t ′ (n) can be expressed by the following equation (17).
θ ′ (n) = ωe (0) × t ′ (n) (17)

  Next, the corrected induced voltage amplitude value calculation unit 14 calculates the correlation value obtained by the correlation process in which the fundamental wave trigonometric function having the corrected rotation angle θ ′ (n) as a variable is multiplied by the corrected interphase induced voltage Vuv ′ (n). Based on the above, the corrected interphase induced voltage effective value E′ruv is calculated.

That is, first, the corrected induced voltage amplitude value calculation unit 14 uses the corrected rotation angle θ ′ (n) as shown in the following equations (18) and (19), at the corrected sampling time point t ′ (n). A corrected sine wave function S (n) that is a fundamental wave sine component of a trigonometric function and a corrected cosine wave function C (n) that is a fundamental wave cosine component are generated.
S (n) = sin {θ ′ (n)} [0 ≦ θ ′ (n) ≦ 2 kπ]
S (n) = 0 [θ ′ (n)> 2kπ] (18)
C (n) = cos {θ ′ (n)} [0 ≦ θ ′ (n) ≦ 2 kπ]
C (n) = 0 [θ ′ (n)> 2kπ] (19)
However, k is the number of electrical angular cycles, and is the number of cycles not exceeding the sampling number m.

Further, as shown in equations (20) and (21), correlation processing between the corrected correlation induced voltage V′uv and the corrected sine wave function S (n), and the corrected correlation induced voltage V′uv and the corrected cosine wave function C Correlation processing with (n) is performed to obtain respective correlation values E′sin and E′cos.

この場合における全体相関値Ｅ´ruvの大きさ｜Ｅ´ruv｜は、式（２２）に示すように、相関値Ｅ´sinと相関値Ｅ´cosとの２乗和の平方根の実効値（｜Ｅ´uv｜／２＾（１／２））として求められる。また、全体相関値Ｅ´ruvの位相φ´は、式（１３）に示すように、相関値Ｅ´sinを相関値Ｅ´cosで除算した値のarctanとして求められる。図６は、補正相間誘起電圧Ｖ´uvと、式（２２）の大きさ｜Ｅ´ruv｜（実効値）と式（２３）の位相を有した基本波の三角関数ｆとの関係を示す図である。式（２０）、（２１）に示した相関処理によって、図６に示すように、補正相間誘起電圧Ｖ´uvから基本波成分の補正相間誘起電圧Ｖ´uv1が抽出されたことになる。すなわち、全体相関値Ｅ´ruvの大きさ｜Ｅ´ruv｜は、補正相間誘起電圧Ｖ´uv1の実効値であって、補正相間誘起電圧Ｖ´uvから基本波成分を抽出した値に相当する。 The correlation value E′sin between the corrected correlation induced voltage V′uv and the corrected sine wave function S (n) and the correlation value E′cos between the corrected correlation induced voltage V′uv and the corrected cosine wave function Cη (n). The magnitude | E'uv | and the phase φ 'of the overall correlation value E'uv are obtained by the following equations (22) and (23) using

The magnitude | E′ruv | of the overall correlation value E′ruv in this case is the effective value of the square root of the sum of squares of the correlation value E′sin and the correlation value E′cos, as shown in the equation (22). | E′uv | / 2 ^ (1/2)). Further, the phase φ ′ of the overall correlation value E′ruv is obtained as arctan of a value obtained by dividing the correlation value E′sin by the correlation value E′cos, as shown in Expression (13). FIG. 6 shows the relationship between the corrected interphase induced voltage V′uv, the magnitude | E′ruv | (effective value) of Equation (22), and the trigonometric function f of the fundamental wave having the phase of Equation (23). FIG. By the correlation processing shown in equations (20) and (21), as shown in FIG. 6, the corrected interphase induced voltage V′uv1 of the fundamental wave component is extracted from the corrected interphase induced voltage V′uv. That is, the magnitude | E'ruv | of the overall correlation value E'ruv is an effective value of the corrected interphase induced voltage V'uv1, and corresponds to a value obtained by extracting the fundamental wave component from the corrected interphase induced voltage V'uv. .

  The flux linkage calculating unit 15 divides the corrected interphase induced voltage effective value E′ruv calculated by the corrected induced voltage amplitude value calculating unit 14 by the electrical angular angular velocity ωe (0) at the start of the free-run state. Calculated as the amount of flux linkage of MO. That is, the interlinkage flux effective amount ψre is obtained by using the correlation induced voltage Eruv in the equation (1) as the corrected interphase induced voltage effective value E′ruv and the electrical angular angular velocity ωe as the electrical angular angular velocity ωe (0). The control by the motor control device 1 is often controlled by using the value of the fundamental wave component and the effective value of the interphase induced voltage, and the above-described linkage flux effective amount ψre can be used as it is as a control amount, which is preferable. It is.

  The input / output unit 16 is an input / output interface realized by a touch panel or the like. The storage unit 17 is realized by a memory or a hard disk. The linkage flux effective amount Ψre obtained by the linkage flux amount calculation unit 15 is stored in the storage unit 17. Further, the effective flux linkage amount Ψre obtained by the flux linkage calculation unit 15 is output from the input / output unit 16. The flux linkage effective amount Ψre output from the input / output unit 16 or stored in the storage unit 17 is then set in the motor control device 1.

(Interlinkage flux measurement process)
Here, with reference to the flowchart shown in FIG. 7, the interlinkage magnetic flux amount measurement processing procedure by the interlinkage magnetic flux amount measurement device 10 will be described. First, the induced voltage measuring unit 11 stops the power supply that causes the rotor 30 to shift to the free-run state by stopping the supply power to the motor MO from the state where the rotor 30 in the motor MO is rotating at a constant rotational speed N. The electrical angular angular velocity ωe at the time of reception of the signal SG is acquired, and the interphase induced voltage Vuv between the U-phase coil 31 and the V-phase coil 32 is measured at a predetermined sampling period Ts from the time of reception of the power supply stop signal SG ( Step S101).

  After that, the attenuation amount determination unit 12 assumes that the time change of the measured interphase induced voltage Vuv is exponential decay and multiplies the trigonometric function obtained by multiplying the decay exponential function η (n) with the attenuation coefficient α as a variable. The optimum attenuation coefficient αmax when the correlation value obtained by the correlation process multiplied by Vuv (n) is maximized is determined (step S102).

  The correction unit 13 uses the optimum attenuation exponent function ηα (n) having the optimum attenuation coefficient αmax to set the measured correlation induced voltage Vuv as a value that does not cause the rotor 30 to decelerate after the free-run state. In order to perform reverse conversion to return to Vuv, a corrected sampling time point t ′ obtained by correcting the time series sampling time point t (n) corresponding to the deceleration of the electrical angular angular velocity ωe of the rotor 30 to a state in which the rotor 30 does not decelerate. (N) is obtained, and the corrected interphase induced voltage Vuv ′ (n) and the corrected rotation angle θ ′ (n) at the corrected sampling time t ′ (n) are calculated (step S103).

  The corrected induced voltage amplitude value calculation unit 14 is based on the correlation value obtained by the correlation process in which the fundamental wave trigonometric function having the corrected rotation angle θ ′ (n) as a variable is multiplied by the corrected interphase induced voltage Vuv ′ (n). The corrected interphase induced voltage effective value E′ruv is calculated (step S104).

  The flux linkage calculating unit 15 divides the corrected interphase induced voltage effective value E′ruv calculated by the corrected induced voltage amplitude value calculating unit 14 by the electrical angular angular velocity ωe (0) at the start of the free-run state. Calculation is made as the amount of flux linkage of MO (step S105), and this processing is terminated.

  The above-described interlinkage magnetic flux amount measurement processing procedure is stored in the storage unit 17 as a program to be executed by the interlinkage magnetic flux amount measurement device 10 and is executed by being read out by the control unit CT. This program is file data in an installable or executable format and is read by a computer such as a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk), USB medium, or flash memory. It is provided by being recorded on a possible recording medium.

  The program to be executed by the flux linkage measuring device 10 may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Furthermore, the program to be executed by the flux linkage measuring device 10 may be provided or distributed via a network such as the Internet.

  In the above-described embodiment, even if the rotating shaft of the rotor 30 is not exposed to the outside of the casing as in the case of the electric motor MO provided in the compressor or the like, the free run is performed according to a predetermined processing procedure or a predetermined program. It is possible to automatically measure the amount of flux linkage of the motor MO in the state. Therefore, accuracy is not affected by the measurer, and measurement with high accuracy is possible. In particular, the interphase induced voltage actually measured includes a high frequency component, and it is difficult to measure the interphase induced voltage of the fundamental wave component with high accuracy by visual observation.

  Further, in the above-described embodiment, the attenuation function of the interphase induced voltage is not a linear function but an attenuation exponent function, so that it is possible to perform highly accurate measurement by correcting the measurement result. In particular, since the exponential function has a value of 1 when the time is 0, normalization of the function is easy.

  In addition, the value of the amount of flux linkage measured in the above-described embodiment could be obtained with the same high accuracy as when the rotor 30 was rotated using an external rotating device.

  In the above-described embodiment, the interphase induced voltage is detected, and the amount of interlinkage magnetic flux of the permanent magnet motor is calculated from the detected interphase induced voltage. However, the interlinkage magnetic flux is detected by detecting the induced voltage of each phase. The amount may be calculated.

  In the above-described embodiment, the induced voltage measuring unit 11 is provided in the interlinkage magnetic flux amount measuring device 10 of the permanent magnet motor. However, the present invention is not limited to this, and for example, the induced voltage is measured in the motor control device 1. The part 11 may be provided. In this case, for example, the electrical angular angular velocity ωe at the time of the transition of the rotor 30 to the free run state is acquired by the motor control device 1, and from the time of the transition to the free run state, the induced voltage measurement unit 11 performs a connection between the motor terminals. The correlation induced voltage is measured, and the electrical angular angular velocity ωe and the induced voltage may be stored in a storage unit provided in the motor control device 1. In the case of this configuration, data stored in the storage unit of the motor control device 1 may be transmitted / received to / from the interlinkage magnetic flux amount measuring device 10 of the permanent magnet motor, so that it is not necessary to transmit / receive the angular velocity and the induced voltage in real time. Moreover, even if the motor control device 1 and the interlinkage magnetic flux amount measuring device 10 of the permanent magnet motor are separated from each other, the interlinkage magnetic flux amount can be measured by transmitting and receiving data.

DESCRIPTION OF SYMBOLS 1 Electric motor control apparatus 2 Voltage command production | generation part 3 Drive part 4 Current detection part 5 Phase / angular velocity detection part 6 Decoupling control part 10 Linkage magnetic flux measuring device 11 of permanent magnet motor 11 Induced voltage measurement part 12 Attenuation amount determination part 13 Correction unit 14 Correction induced voltage amplitude value calculation unit 15 Linkage magnetic flux amount calculation unit 16 Input / output unit 17 Storage unit 20 Voltage detection unit 21, 22 Voltage detection sensor 30 Permanent magnet rotor 31 U phase coil 32 V phase coil 33 W phase Coil 41, 42 Current sensor CT controller MO Permanent magnet motor SG Power supply stop signal Vdc External DC voltage αmax Optimum damping coefficient ωm Mechanical angular velocity command ωm * Mechanical angular velocity command ωe Electrical angular velocity θe Rotational angle Id, Iq, iu, iv Current Vd * d-axis voltage command value Vq * q-axis voltage command value Vu U-phase voltage Vv V-phase voltage

Claims (5)

A method for measuring the amount of flux linkage in a permanent magnet motor for measuring the amount of flux linkage in a permanent magnet motor,
While acquiring the rotational speed of the permanent magnet rotor at the time of stopping the power supply for shifting the permanent magnet rotor to the free-run state by stopping the power supply to the permanent magnet motor from the state where the permanent magnet rotor is rotating An induced voltage measurement step of measuring the induced voltage of the electric motor at a predetermined sampling period from the time of stopping the power supply;
An attenuation determination step for determining the attenuation of the measured induced voltage over time as an exponential attenuation; and
A correction sampling time point obtained by correcting a time-series sampling time point corresponding to the reduction of the rotation speed of the permanent magnet rotor based on the attenuation index function having the attenuation amount is obtained, and a corrected induced voltage at the correction sampling time point And a correction step for calculating a correction rotation angle;
A corrected induced voltage amplitude value calculating step for calculating an amplitude value of the corrected induced voltage;
A linkage flux amount calculating step of calculating a value obtained by dividing the amplitude value of the correction induced voltage by the rotation speed value at the start of a free-run state as the linkage flux amount of the permanent magnet motor;
A method for measuring the amount of magnetic flux linkage of a permanent magnet motor. A method for measuring the amount of flux linkage in a permanent magnet motor for measuring the amount of flux linkage in a permanent magnet motor,
Obtaining the rotational speed of the permanent magnet rotor at the time of stopping the power supply for shifting the permanent magnet rotor to a free-run state by stopping the power supply to the permanent magnet motor from the state where the permanent magnet rotor is rotating And an induced voltage measurement step for measuring the induced voltage of the electric motor at a predetermined sampling period from the time when the power supply is stopped,
The time variation of the measured induced voltage is assumed to be exponential decay, and is determined by a correlation process in which the induced voltage is multiplied by a trigonometric function obtained by multiplying the decay exponential function with the exponential decay coefficient as a variable that determines the amount of decay. An optimum attenuation coefficient determining step for determining an optimum attenuation coefficient when the obtained correlation value is maximized;
A correction sampling time point obtained by correcting a time-series sampling time point corresponding to a reduction in the rotational speed of the permanent magnet rotor is obtained based on the optimum damping index function having the optimum damping coefficient, and further, a correction induction at the correction sampling time point is obtained. A correction step for calculating a voltage and a correction rotation angle;
Correction induced voltage amplitude value calculation for calculating a corrected induced voltage amplitude value of the fundamental wave component based on a correlation value obtained by a correlation process obtained by multiplying the correction wave induced voltage by a fundamental wave trigonometric function having the correction rotation angle as a variable Steps,
A linkage magnetic flux amount calculating step of calculating a value obtained by dividing the correction induced voltage amplitude value by the rotation speed at the start of a free-run state as the flux linkage amount of the permanent magnet motor;
A method for measuring the amount of magnetic flux linkage of a permanent magnet motor.   The square root of the sum of squares for the interphase value using a sine wave and the interphase value using a cosine wave is used in the optimum attenuation coefficient determination step and the corrected induced voltage amplitude value calculation step. Of measuring the amount of magnetic flux linkage of a permanent magnet electric motor. A program for measuring the amount of flux linkage in a permanent magnet motor that measures the amount of flux linkage in a permanent magnet motor,
In the control unit,
While acquiring the rotational speed of the permanent magnet rotor at the time of stopping the power supply for shifting the permanent magnet rotor to the free-run state by stopping the power supply to the permanent magnet motor from the state where the permanent magnet rotor is rotating An induced voltage measurement step of measuring the induced voltage of the electric motor at a predetermined sampling period from the time of stopping the power supply;
An attenuation determination step for determining the attenuation of the measured induced voltage over time as an exponential attenuation; and
A correction sampling time point obtained by correcting a time-series sampling time point corresponding to the reduction of the rotation speed of the permanent magnet rotor based on the attenuation index function having the attenuation amount is obtained, and a corrected induced voltage at the correction sampling time point And a correction step for calculating a correction rotation angle;
A corrected induced voltage amplitude value calculating step for calculating an amplitude value of the corrected induced voltage;
A linkage flux amount calculating step of calculating a value obtained by dividing the amplitude value of the correction induced voltage by the rotation speed value at the start of a free-run state as the linkage flux amount of the permanent magnet motor;
A program for measuring the amount of flux linkage in a permanent magnet motor, characterized in that An apparatus for measuring the amount of flux linkage in a permanent magnet motor for measuring the amount of flux linkage in a permanent magnet motor,
While acquiring the rotational speed of the permanent magnet rotor at the time of stopping the power supply for shifting the permanent magnet rotor to the free-run state by stopping the power supply to the permanent magnet motor from the state where the permanent magnet rotor is rotating An induced voltage measuring unit that measures the induced voltage of the electric motor at a predetermined sampling period from the time when the power supply is stopped;
An attenuation amount determination unit that determines the amount of attenuation as the exponential attenuation of the time change of the measured induced voltage;
A correction sampling time point obtained by correcting a time-series sampling time point corresponding to the reduction of the rotation speed of the permanent magnet rotor based on the attenuation index function having the attenuation amount is obtained, and a corrected induced voltage at the correction sampling time point And a correction unit for calculating a correction rotation angle;
A corrected induced voltage amplitude value calculating unit for calculating an amplitude value of the corrected induced voltage;
An interlinkage magnetic flux amount calculation unit for calculating a value obtained by dividing the amplitude value of the correction induced voltage by the rotation speed value at the start of a free-run state as an interlinkage magnetic flux amount of the permanent magnet motor;
A flux linkage measuring device for a permanent magnet electric motor, comprising:

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