JP2014117069A - Control apparatus for ac rotary machine and control method for ac rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress vibration and noise during driving by stably driving an AC rotary machine with a small volume of electric power.SOLUTION: The present invention comprises a controller (101) that supplies desired electric power through a power feeding section (3) to an AC rotary machine (1) with frequency characteristics at an inductance. The controller (101) supplies electric power with such a frequency (fh) that a function including the inductance of the AC rotary machine (1) becomes an extreme value and electric power with a fundamental wave frequency to the AC rotary machine (1) through the power feeding section (3).

Description

  The present invention relates to control of an AC rotating machine, and more particularly, to an AC rotating machine control device and an AC rotating machine control method that can reduce vibration and noise during driving by stably driving with less electric power.

  When driving an AC rotating machine, it is necessary to detect or estimate the position of the rotor and supply electric power to the motor at an appropriate phase corresponding to the position of the rotor in order to generate a desired torque. .

  Here, in order to estimate the rotor magnetic pole position of an AC rotating machine having electrical saliency, a case where a voltage or current having a frequency higher than the fundamental frequency is superimposed on the fundamental wave and applied to the AC rotating machine is considered. . In this case, by changing the frequency or amplitude of the superimposed voltage or current, the high-frequency spectrum is dispersed, or the average value of the amplitude of a specific high-frequency component is reduced to reduce electromagnetic noise from the AC rotating machine. The motor control device is realized (see, for example, Patent Document 1).

JP 2004-343833 A

However, the prior art has the following problems.
The conventional motor control device described in Patent Document 1 does not consider the frequency characteristics of the winding inductance of the AC rotating machine. When such a conventional technique is applied to an AC rotating machine whose electrical saliency varies depending on the frequency of the superimposed voltage, current, or power, the frequency of the superimposed voltage, current, or power Depending on the frequency, it is used in the frequency region where the saliency is small.

  As a result, in order to obtain the estimated accuracy of the desired rotor position, the amplitude of power, voltage, or current required in addition to driving the AC rotator increases, resulting in loss or AC rotation occurring in the AC rotator or power feeding means. There is a problem that vibration and noise generated from the machine increase.

  The present invention has been made in order to solve the above-described problems, and controls an AC rotating machine that stably drives an AC rotating machine with a small amount of electric power and reduces vibration and noise during driving. It aims at obtaining the control method of an AC rotating machine.

  An AC rotating machine control apparatus according to the present invention is an AC rotating machine control apparatus including a control unit that supplies desired power to an AC rotating machine having a frequency characteristic in inductance via a power feeding unit. The control unit supplies the AC rotating machine with power having a frequency at which the function including the inductance of the AC rotating machine has an extreme value and power having the fundamental frequency through the power feeding unit.

  Moreover, the control method of the AC rotating machine according to the present invention is a control method of an AC rotating machine including a control unit that supplies desired power to the AC rotating machine having a frequency characteristic in inductance via the power feeding unit. Then, the control unit includes a step of feeding the AC rotating machine with the power having the frequency at which the function including the inductance of the AC rotating machine becomes an extreme value and the power having the fundamental frequency through the power feeding unit.

  According to the present invention, the AC rotating machine is stably driven with less power by feeding power to the AC rotating machine with power at a frequency at which the function including the inductance is an extreme value or near the extreme value and power at the fundamental frequency, It is possible to obtain an AC rotating machine control device and an AC rotating machine control method that reduce vibration and noise during driving.

It is a block diagram which shows the structure of the whole system containing the control apparatus of the alternating current rotating machine in Embodiment 1 of this invention. It is explanatory drawing which showed the three-phase alternating current voltage which the high frequency voltage generator in Embodiment 1 of this invention outputs. It is a block showing the internal calculation of the position estimation means in Embodiment 1 of this invention. It is explanatory drawing of the stator and rotor structure of AC rotary machine 1 in Embodiment 1 of this invention. It is a perspective view of the rotor of AC rotating machine 1 in Embodiment 1 of the present invention. It is the figure which showed the relationship between the rotor position of the AC rotary machine 1 at the time of no-load drive of the AC rotary machine 1 which concerns on Embodiment 1 of this invention, and an inductance. In Embodiment 1 of this invention, when the high frequency voltage at the time of no load is applied, it is a figure which shows the locus | trajectory of the current vector based on the rotation biaxial current shown in FIG. It is a figure which shows the frequency characteristic of the parameter | index of the saliency in Embodiment 1 of this invention. It is a figure which shows the frequency characteristic of the difference of the 1st inductance in Embodiment 1 of this invention, and a 2nd inductance. It is a figure which shows the frequency characteristic of ratio of the 1st inductance in Embodiment 1 of this invention, and a 2nd inductance. It is a block diagram which shows the structure of the whole system containing the control apparatus of the alternating current rotating machine in Embodiment 2 of this invention. It is explanatory drawing which showed the d-axis high frequency current command and q-axis high frequency current command which the high frequency current generator in Embodiment 2 of this invention outputs. It is a block showing the internal calculation of the position estimation means in Embodiment 2 of this invention. It is a block diagram which shows the structure of the whole system containing the control apparatus of the AC rotary machine in Embodiment 3 of this invention. It is the figure which showed the relationship between the rotor position of the alternating current rotating machine 1 at the time of the load of the alternating current rotating machine 1 which concerns on Embodiment 3 of this invention (at the time of current supply of a fundamental frequency), and an inductance.

  Hereinafter, preferred embodiments of an AC rotating machine control device and an AC rotating machine control method according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of the entire system including a control device for an AC rotating machine according to Embodiment 1 of the present invention. The control device for an AC rotating machine in the first embodiment is configured as a control unit 101, and by supplying desired power via the power supply unit 3 based on the detection result by the current detection unit 2, The AC rotating machine 1 is controlled.

  Here, the AC rotating machine 1 in FIG. 1 is an AC rotating machine having frequency characteristics in inductance, and details will be described later.

  The AC rotating machine 1 is connected to the power supply means 3. Here, the power supply means 3 is a power converter that can output AC power, such as an inverter, a cycloconverter, or a matrix converter. The power supply unit 3 drives the AC rotating machine 1 by supplying power to the AC rotating machine 1.

  Further, the current detection means 2 detects the current flowing through the AC rotating machine 1. The current detection unit 2 according to the first embodiment detects a current for two phases (a U-phase current iu and a V-phase current iv in the example of FIG. 1) from a power line connecting the AC rotating machine 1 and the power feeding unit 3. To do. The current detection means 2 may detect any two phases of the U-phase current iu, V-phase current iv, and W-phase current iw, or may detect all phase currents. Good.

  Alternatively, when the power supply unit 3 is an inverter, the current detection unit 2 calculates current using a method of regenerating U, V, and W phase currents iu, iv, and iw from a DC bus current that is an input of the inverter. It may be detected.

  Next, a detailed configuration of the control unit 101 will be described. The control means 101 includes a three-phase / two-phase converter 4, a coordinate converter 5, a d-axis current controller 6, a q-axis current controller 7, a coordinate converter 8, a two-phase / three-phase converter 9, and an adder 10. , Position estimation means 102, subtractor 103, and high-frequency voltage generator 104.

  The control unit 101 uses a CPU such as a microcomputer or a DSP to perform voltage commands Vup *, Vvp *, Vwp * based on current value information iu, iv obtained by A / D converting the current value detected by the current detection unit 2. Is output to the power supply means 3.

  The three-phase / two-phase converter 4 converts the U-phase current iu and the V-phase current iv detected by the current detection means 2 into currents iαs and iβs on a fixed two-axis (α-β axis). The coordinate converter 5 converts the currents iαs and iβs into rotating biaxial (dq axis) currents id and iq using the estimated position θp output from the position estimation unit 102 described later.

  The current command values id * and iq * are obtained based on the position command, speed command, torque command, and the like of the AC rotating machine 1. Therefore, the generation sources of the current command values id * and iq * are omitted in FIG. 1 because they are publicly known techniques.

  The subtractor 103 determines the d-axis current deviation Δid from the difference between the current command value id * and the output id of the coordinate converter 5, and the difference between the current command value iq * and the output iq of the coordinate converter 5, respectively. Q-axis current deviation Δiq is calculated.

  The d-axis current controller 6 outputs a d-axis voltage command value Vd * as a control amount for setting the d-axis current deviation Δid to 0 by using proportional integral control or the like. Similarly, the q-axis current controller 7 outputs the q-axis voltage command value Vq * as a control amount for setting the q-axis current deviation Δiq to 0 by using proportional integral control or the like.

  The coordinate converter 8 converts the d-axis voltage command value Vd * and the q-axis voltage command value Vq * to a voltage on the fixed two axes (α-β axis) by using an estimated position θp output from the position estimation unit 102 described later. Convert to command values Vα * and Vβ *.

  The two-phase / three-phase converter 9 converts the voltage command values Vαs * and Vβs * into three-phase voltage command values Vu *, Vv *, and Vw * as voltage command values.

  The high frequency voltage generator 104 outputs a three-phase AC voltage Vuh, Vvh, Vwh having a cycle Tvh, a frequency fvh = (1 / Tvh), and an amplitude Vh. FIG. 2 is an explanatory diagram showing the three-phase AC voltages Vuh, Vvh, and Vwh output from the high-frequency voltage generator 104 according to Embodiment 1 of the present invention.

  As shown in FIG. 2, in the first embodiment, the three-phase AC voltages Vuh, Vvh, and Vwh are sine wave AC voltages, but the present invention is not limited to sine wave AC voltages. . For example, a rectangular wave voltage, a square wave voltage, a sawtooth wave voltage, or the like having a fundamental wave period of Tvh may be used as the sine wave AC voltage. The cycle Th of the three-phase AC voltage will be described later.

  The adder 10 includes the three-phase voltage command values Vu *, Vv *, Vw * output from the two-phase / three-phase converter 9 and the three-phase AC voltages Vuh, Vvh, Vwh output from the high-frequency voltage generator 104. Are added to output the voltage commands Vuh *, Vvh *, and Vwh * to be output to the power supply unit 3.

  Next, the position estimation unit 102 will be described. The position estimation means 102 receives the two-phase currents iαs and iβs and outputs the estimated position θp. FIG. 3 is a block showing the internal calculation of the position estimation means 102 in Embodiment 1 of the present invention. The position estimation unit 102 shown in FIG. 3 includes a Fourier transformer 20, a multiplier 21, a subtracter 22, and a position calculator 23.

  The Fourier transformer 20 has components having the same frequency as the frequency fvh of the high-frequency voltages Vu, Vv, and Vw that are generated in the AC rotating machine 1 by applying the high-frequency voltages Vuh, Vvh, and Vwh from the two-phase currents iαs and iβs. Amplitudes (sizes) Iαs and Iβs are extracted.

  The multiplier 21 squares Iαs and Iβs, which are outputs of the Fourier transformer 20, and outputs (Iαs · Iαs) and (Iβs · Iβs). The subtracter 22 subtracts (Iαs · Iαs) from (Iβs · Iβs) and outputs ΔIαβ. Further, the position calculator 23 calculates the estimated position θp from ΔIαβ that is the output of the subtractor 22.

  The estimated position θp obtained in this way is an estimated value obtained by calculation, not directly detecting the position using a position detection sensor such as a resolver or an encoder. That is, obtaining the estimated position θp in the first embodiment means that the correct rotor position can be estimated by the position estimating means 102. Hereinafter, the processing content for obtaining the estimated position θp by the position estimating means 102 will be described more specifically.

  When the AC rotating machine 1 is a permanent magnet type synchronous rotating machine, the voltage equation at the fixed orthogonal coordinates (α-β axis) can be expressed as the following equation (1).

  Assuming that the rotating machine is stopped or operating at low speed, ω = 0. When the differential operator P is replaced with the Laplace operator s, the currents iαs and iβs in the fixed orthogonal coordinates are expressed by the following expression (2).

  Here, when the high frequency voltages Vuh, Vvh, Vwh having an angular frequency ωh (= 2π / (Tvh)) sufficiently higher than the angular frequency of the AC voltage for driving the AC rotating machine 1 from the high frequency voltage generator 104 are applied. Assume. In this case, R << Lα · ωh and R << Lβ · ωh are satisfied (when s = jωh (j is an imaginary unit)), and when the influence of the stator resistance R is ignored, the above equation (2) Becomes the following formula (3).

  Further, the high frequency voltages Vuh, Vvh, Vwh applied from the high frequency voltage generator 104 can be expressed by the following equation (4) in fixed orthogonal coordinates.

  Further, the high-frequency voltage in the fixed orthogonal coordinates of the above equation (4) is expressed by the following equation (5), and the above equation (4) is substituted into this equation (5), and s = jωh (j is an imaginary unit) Then, the following formula (6) is obtained.

  As shown in the above equation (6), it can be seen that the rotor position information θ (= estimated position θp) is included in the amplitudes of the currents iαs and iβs in the fixed orthogonal coordinates. Therefore, the Fourier transformer 20 extracts the amplitudes Iαs and Iβs of the currents iαs and iβs in fixed orthogonal coordinates.

  That is, by applying the high-frequency voltages Vuh, Vvh, Vwh to the AC rotating machine 1 from the currents iαs, iβs generated in the AC rotating machine 1 by applying the high-frequency voltages Vuh, Vvh, Vwh by the Fourier transformer 20. The same frequency component as the frequency fvh of the generated high-frequency voltages Vu, Vv, Vw is extracted, and the amplitudes Iαs, Iβs are obtained. Then, based on the amplitudes Iαs and Iβs extracted by the Fourier transformer 20, a term including only the rotor position information θ is extracted by performing an operation as shown in the following equation (7).

  In order to realize this calculation, only the information on the rotor position θ is obtained by subtracting (Iαs · Iαs) from (Iβs · Iβs) which is the output of the multiplier 21 and the multiplier 21 that square the amplitudes Iαs and Iβs, respectively. A subtracter 22 that outputs ΔIαβ is used.

  The position calculator 23 calculates θ (estimated position θp) by calculating the inverse cosine of cos 2θ included in the above equation (7). The calculation of the estimated position θp is not an inverse cosine calculation, but a table storing the value of cos2θ may be prepared, and the estimated position θp may be obtained based on the value of cos2θ stored as a table in the storage device.

  Next, the position estimation accuracy of the position estimation unit 102 will be described. The sum Iαβ of (Iβs · Iβs) and (Iαs · Iαs), which is the output of the multiplier 21, is expressed by the following equation (8).

  The above equation (8) is a term proportional to the square of the amplitude of the frequency component equal to the frequency fvh of the high frequency voltage in the current flowing through the AC rotating machine 1, and the larger the value obtained by the above equation (8), The amplitude of the component of the frequency fvh of the high-frequency voltage is increased.

  The amplitude component of cos 2θ in the above equation (7) is shown in the following equation (9). Further, substituting the above equation (8) into the following equation (9) yields the following equation (10).

  Here, when the U-phase current iu and the V-phase current iv are input to the control means 101, a quantization error accompanying A / D conversion occurs. For this reason, quantization errors also occur in the α-phase current iα and the β-phase current iβ, and ΔIαβ expressed by the above equation (7) also causes an error accompanying quantization. Therefore, the larger the value obtained by the above equation (9), which is the amplitude of ΔIαβ, is, the smaller the influence of the quantization error is, and the smaller the error of the estimated position θp obtained by the position calculator 23 is.

  From the above equation (10), there are two methods for increasing the amplitude of ΔIαβ. The first method is a method of increasing Iαβ, and the second method is a method of increasing l or the absolute value of l.

  The first method for increasing Iαβ is to increase the amplitudes Iαs and Iβs of frequency components equal to the frequency of the high-frequency voltage in the current flowing through the AC rotating machine 1 as can be seen from the above equation (9). Will be. Therefore, this first method is not preferable because it causes an increase in copper loss generated in the windings of the AC rotating machine 1, vibration of the AC rotating machine 1, and an increase in noise.

  On the other hand, the second method for increasing the absolute value of l or l has the advantage that the above-described problem does not occur because l does not depend on Iαs and Iβs. Here, l is an amount proportional to the difference between the d-axis inductance Ldh and the q-axis inductance Lqh according to the above equation (1). Therefore, as the absolute value of l or l increases, the saliency of the AC rotating machine 1 becomes large.

  From the above, in order to obtain the estimated accuracy of the estimated position θp without causing an increase in copper loss generated in the winding of the AC rotating machine 1 and an increase in vibration and noise of the AC rotating machine 1, the AC rotating machine 1 It is sufficient if the saliency can be increased.

  Next, the details of the AC rotating machine 1 will be described. The AC rotating machine 1 described here is a surface magnet type permanent magnet synchronous rotating machine. FIG. 4 is an explanatory diagram of the stator / rotor structure of AC rotating machine 1 according to Embodiment 1 of the present invention. In order to help understanding, in FIG. 4, a cross-sectional view of the AC rotating machine 1 is drawn in a straight line, and two rotor positions d and q are shown.

  Here, the AC rotating machine 1 has a stator core 201, a stator having an armature winding 202, and a conductor 206 disposed around a permanent magnet 204. Although FIG. 4 shows a four-pole AC rotating machine, the number of poles and the number of slots are not limited to this. Moreover, N and S in FIG. 4 have shown the polarity of the permanent magnet.

  FIG. 5 is a perspective view of the rotor of AC rotating machine 1 according to the first embodiment of the present invention. More specifically, FIG. 5 is a diagram illustrating a configuration example corresponding to FIG. 4 in the case of a 10-pole rotor. As shown in FIG. 5, conductors 306 and 308 are arranged around the permanent magnets 304. Here, since the conductor 306 and the conductor 308 are closed circuits, they correspond to conductive circuits.

  Since the conductor 306 and the conductor 308 are arranged around the permanent magnet 304 and the rotor of the AC rotating machine 1 has a conduction circuit, when a high frequency voltage is applied to the AC rotating machine 1, a vortex of the frequency of the high frequency voltage is applied to the conduction circuit. Current flows. And the magnetic flux by an eddy current acts so that the magnetic flux by the permanent magnet 304 may be canceled in the gap part between a stator and a rotor.

  Returning to FIG. 4, the rotor position d and the rotor position q having the largest inductance difference with respect to the rotor position are compared. The waveform in FIG. 4 represents the magnetic flux 207 generated by the eddy current flowing through the armature when the high frequency voltage is applied. However, for the sake of simplicity, only the fundamental wave component is shown.

  First, when the rotor position is d, the magnetic flux 207 generated by the eddy current flowing in the armature is linked between, for example, the conductors 206a and 206b, and the eddy current flows through the conductor 206. The eddy current cancels out the magnetic flux generated by the armature d-axis current, and the inductance is reduced.

  On the other hand, when the rotor position is q, for example, the interlinkage between 206a and 206b of the magnetic flux 207 generated by the eddy current cancels out, so the eddy current does not flow through the conductor and the inductance also changes. do not do. As described above, a difference occurs in inductance depending on the position of the rotor, and saliency is generated.

  FIG. 6 is a diagram showing the relationship between the rotor position of the AC rotating machine 1 and the inductance during no-load driving of the AC rotating machine 1 according to Embodiment 1 of the present invention, and shows the saliency. In FIG. 6, the horizontal axis represents the rotor position (electrical angle) of the AC rotating machine 1, and the vertical axis represents the inductance with respect to the rotor position. Inductance is shown when the frequency of the high-frequency voltage is f1, f2, and f3 in ascending order.

  Here, if the maximum value is the first inductance L1 and the minimum value is the second inductance L2 among the inductances with respect to the rotor position, the inductance is 0 and 180 degrees at the frequencies f2 and f3, the minimum value is 90 degrees, The maximum value is taken at 270 degrees. Therefore, in this case, L1 is equal to the q-axis inductance Lqh, and L2 is equal to the d-axis inductance Ldh.

  In FIG. 6, the inductance values at 90 degrees and 270 degrees of frequencies f1, f2, and f3 are L1 (f1), L1 (f2), and L1 (f3), respectively, and the inductance values at 0 degrees and 180 degrees are L2 (f1). ), L2 (f2), and L2 (f3). When compared with the first inductance L1, there is almost no difference among L1 (f1), L1 (f2), and L1 (f3). When compared with the second inductance L2, L2 (f1) is Highest and almost equal to L1 (f1).

  As the frequency of the high-frequency voltage increases from f1 to f2 and f3, the second inductance L2 becomes L2 (f2) and L2 (f3), and the difference between the first inductance L1 and the second inductance L2 increases. This is because the magnitude of the magnetic flux generated by the eddy current flowing through the conductor 206 of the AC rotating machine 1 varies depending on the frequency of the high-frequency voltage, and a difference occurs between the first inductance and the second inductance.

  As described above, the second inductance is a function with respect to the frequency of the high-frequency voltage, and the saliency also varies depending on the frequency of the high-frequency voltage.

  FIG. 7 shows the locus of the current vector based on the rotating biaxial (dq axis) currents id and iq shown in FIG. 1 when a high frequency voltage at no load is applied in the first embodiment of the present invention. FIG. More specifically, the locus of the current vector when the frequency of the high-frequency voltage is f1, f2, and f3 is shown, and the magnitude of the vector when the vector direction coincides with the d-axis is expressed as Idh (f1), Let Idh (f2) and Idh (f3) be the magnitudes of the vectors when the vector directions coincide with the q axis, respectively, as Iqh (f1), Iqh (f2), and Iqh (f3).

  In FIG. 7, the d-axis current is the horizontal axis and the q-axis current is the vertical axis. Of the frequencies f1, f2, and f3, the current vector locus for f1 having the lowest frequency is almost a perfect circle, and Idh (f1) ≈Iqh (f1). As the frequency is increased from f1 to f2 and f3, the difference between the current vectors Iqh (f1), Iqh (f2), and Iqh (f3) in the q-axis direction is small, but the current vectors Idh (f1) and Idh in the d-axis direction are small. It can be seen that (f2) and Idh (f3) increase in this order.

  This is due to the fact that the inductance L2 (= Ld) at 0 degree and 180 degrees decreases as the inductance at the rotor position in FIG. 6 increases the frequency of the high frequency voltage from f1 to f2, f3. Yes. Here, if the difference between the current vector Idh in the d-axis direction and the current vector Iqh in the q-axis direction is ΔIh, the difference between the first inductance L1 and the second inductance L2 increases as the difference in ΔIh increases. The polarity increases and the position estimation accuracy can be improved.

  The difference ΔIh between the current vector Idh in the d-axis direction and the current vector Iqh in the q-axis direction is described, for example, in Japanese Patent Laid-Open No. 2011-4583, and is expressed by the following equation (11). Is given. Here, Vha is a rotation biaxial (dq axis) conversion value of the high-frequency voltage.

  Focusing on the relationship between the d-axis inductance Ldh and q-axis inductance Lqh and ΔIh from the above equation (11), ΔIh increases as the term expressed by the following equation (12) increases, improving the position estimation accuracy. I understand that I can do it. Therefore, the term represented by the following formula (12) is defined as an index of saliency.

  As described above, L1 is equal to the q-axis inductance Lqh, and L2 is equal to the d-axis inductance Ldh. Therefore, the above equation (12) can be expressed by the following equation (13), and the saliency index is equal to the difference between the reciprocal of the second inductance and the reciprocal of the first inductance.

  FIG. 8 is a diagram showing the frequency characteristics of the saliency index in the first embodiment of the present invention. The horizontal axis is the frequency of the high-frequency voltage, the vertical axis is an index of saliency (the difference between the reciprocal of the second inductance and the reciprocal of the first inductance), and the larger the value on the vertical axis, the greater the position estimation accuracy. Can be improved.

  In other words, as the value on the vertical axis is larger, position estimation accuracy can be ensured with less voltage, current, or power, and the AC rotating machine 1 can be driven stably. From FIG. 8, the index of saliency (the difference between the reciprocal of the second inductance L2 and the reciprocal of the first inductance L1) takes an extreme value at the frequency fh.

  FIG. 9 is a diagram illustrating a frequency characteristic of a difference between the first inductance L1 and the second inductance L2 in the first embodiment of the present invention. The horizontal axis represents the frequency of the high-frequency voltage, the vertical axis represents the difference between the first inductance L1 and the first inductance L2, and the larger the value on the vertical axis, the larger the absolute value of l in the above equation (1). Since it becomes large, the position estimation accuracy can be improved.

  In other words, as the value on the vertical axis is larger, the position estimation accuracy can be secured with less voltage, current, or power, and the AC rotating machine 1 can be driven stably. From FIG. 9, the difference L1-L2 between the first inductance L1 and the second inductance L2 takes an extreme value at the frequency fh.

  FIG. 10 is a diagram showing frequency characteristics of the ratio L1 / L2 between the first inductance L1 and the second inductance L2 in the first embodiment of the present invention. The horizontal axis is the frequency of the high-frequency voltage, the vertical axis is the ratio L2 / L1 between the first inductance L1 and the second inductance L2, and the larger the value on the vertical axis, the larger the saliency, the position The estimation accuracy can be improved.

  In other words, as the value on the vertical axis is larger, the position estimation accuracy can be secured with less voltage, current, or power, and the AC rotating machine 1 can be driven stably. From FIG. 10, the ratio of the second inductance L2 and the first inductance L1 takes an extreme value at the frequency fh.

  As described above, the saliency index (the difference between the reciprocal of the second inductance L2 and the reciprocal of the first inductance L1), the difference between the first inductance L1 and the second inductance L2, and the first inductance L1 The ratio with the second inductance L2 is composed of the first inductance L1 and the second inductance L2, and is a function including the inductance with respect to the frequency of the high frequency voltage, high frequency current or high frequency power. The extreme value (or the maximum value) is taken by fh.

  In the first embodiment, the frequency fvh of the high-frequency voltage (Vuh, Vvh, Vwh) generated by the high-frequency voltage generator is set to coincide with fh or in the vicinity of fh. Apply voltage. As a result, a current including a component of the frequency fh flows through the AC rotating machine 1.

  Considering that the power is a product of voltage and current, the power supply means 3 supplies the AC rotating machine 1 with power at the frequency fh at which the function including the inductance has an extreme value in addition to the power at the fundamental frequency. As a result, in addition to the fundamental frequency, the power required to obtain the desired position estimation accuracy of the AC rotating machine 1 is reduced as compared with the case where power in a frequency band other than the frequencies fh and fh is supplied. The loss, vibration, and noise generated in the AC rotating machine 1 can be reduced.

  As described above, according to the first embodiment, the AC rotating machine can be reduced by feeding the AC rotating machine with the power of the frequency at which the function including the inductance is an extreme value or the vicinity of the extreme value and the power of the fundamental frequency. It can be driven stably with electric power. As a result, it is possible to realize an AC rotating machine control device and an AC rotating machine control method that reduce vibration and noise during driving.

  In the first embodiment described above, the adder 10 uses the output of the two-phase / three-phase converter 9 (Vu *, Vv *, Vw *) and the output of the high-frequency voltage generator (Vuh, Vvh, Vwh). ) Are added. However, the present invention is not limited to this, and may be configured to add the frequency fh or a high-frequency voltage (Vαh, Vβh) near the frequency fh to the output (Vα *, Vβ *) of the coordinate converter 8. Furthermore, the present invention may be configured to add the high frequency voltage (Vdh, Vqh) near the frequency fh to the input (Vdh, Vqh) of the coordinate converter 8.

  Further, the estimation method of the estimated position θp of the rotor of the AC rotating machine 1 is not limited to the configuration of the position estimating means 102 in the first embodiment. All the rotor position estimating means for extracting and estimating the same frequency component as the high frequency voltage in the vicinity of the frequency fh or fh added for estimating the rotor position from the current detected by the current detecting means is the present invention. include.

Embodiment 2. FIG.
FIG. 11 is a block diagram showing a configuration of the entire system including a control device for an AC rotating machine according to Embodiment 2 of the present invention. The control device for the AC rotating machine according to the second embodiment is configured as a control unit 401, and, similarly to the first embodiment, based on the detection result by the current detection unit 2, the power rotation unit 3 is used. The AC rotating machine 1 is controlled by supplying desired power.

  In FIG. 11, components having the same functions as those in the block diagram of FIG. 1 representing the configuration in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Next, a detailed configuration of the control unit 401 will be described. The control means 401 includes a three-phase / two-phase converter 4, a coordinate converter 5, a d-axis current controller 6, a q-axis current controller 7, a coordinate converter 8, a two-phase / three-phase converter 9, and a position estimation means. 402, an adder / subtractor 403, and a high-frequency current generator 405.

  The control unit 401 uses a CPU such as a microcomputer or a DSP to perform voltage commands Vu *, Vv *, Vw * using current value information iu, iv obtained by A / D converting the current value detected by the current detection unit 2. Is output to the power supply means 3. As other operations / functions, the control unit 401 is different from the control unit 101 shown in FIG. 1 in the position estimation unit 402, the adder / subtractor 403, and the high-frequency current generator 405.

  The high-frequency current generator 405 outputs a d-axis high-frequency current command idh * with a period Tih, a frequency fih = 1 / Tih, and an amplitude Ih, and a q-axis high-frequency current command iqh * whose phase is delayed by 90 degrees from the idh *. To do. FIG. 12 is an explanatory diagram showing the d-axis high-frequency current command idh * and the q-axis high-frequency current command iqh * output from the high-frequency current generator 405 according to Embodiment 2 of the present invention.

  The adder / subtractor 403 inputs the current commands id * and iq *, the outputs idh * and iqh * of the high-frequency current generator 405, and the outputs id and iq of the coordinate converter 5, and the following equations (14) and (15) A d-axis current deviation Δid and a q-axis current deviation Δiq are output by the calculation.

  The d-axis current deviation Δid and the q-axis current deviation Δiq are controlled to 0 by the d-axis current controller 6 and the q-axis current controller 7, respectively. From this, when Δid = 0 and Δiq = 0 are substituted into the above equations (14) and (15), respectively, the d-axis current id and the q-axis current iq which are the outputs of the coordinate converter 5 are respectively expressed by the following equations (16 ), (17).

  From the above equations (16) and (17), it can be seen that the d-axis current id and the q-axis current iq flowing through the AC rotating machine 1 include high-frequency current commands idh * and iqh *.

  Next, the position estimation unit 402 will be described. The position estimation unit 402 receives the two-phase voltage commands Vαs * and Vβs * and outputs an estimated position θp. FIG. 13 is a block showing an internal calculation of the position estimation unit 402 according to Embodiment 2 of the present invention. The position estimation means 402 shown in FIG. 13 includes a Fourier transformer 410, a multiplier 411, a subtractor 412, and a position calculator 413.

  The Fourier transformer 410 extracts the amplitudes (magnitudes) Vαa and Vβa of these Vαs * and Vβs * from the two-phase voltage commands Vαs * and Vβs *.

  Multiplier 411 squares Vαa and Vβa, which are outputs from Fourier transformer 410, and outputs (Vαa · Vαa) and (Vβa · Vβa). The subtractor 412 subtracts (Vαa · Vαa) from (Vβa · Vβa) and outputs ΔVαβ. Further, the position calculator 413 calculates the estimated position θp from ΔVαβ that is the output of the subtractor 412.

  Hereinafter, the processing content for obtaining the estimated position θp by the position estimating unit 402 will be described more specifically.

  In the above equation (1), assuming that the rotating machine is stopped or operating at a low speed, ω = 0. When the differential operator P is replaced with the Laplace operator s, the voltages vαs and vβs at the fixed orthogonal coordinates are expressed by the following equation (18).

  Here, it is assumed that the high frequency currents idh and iqh having an angular frequency ωh (= 2π / (Tih)) sufficiently higher than the fundamental frequency of the alternating current for driving the AC rotating machine 1 from the high frequency current generator 405 are energized. . In this case, R << Lα · ωh and R << Lβ · ωh are satisfied (when s = jωh (j is an imaginary unit)), and if the influence of the stator resistance R is ignored, the above equation (18) Is the following equation (19).

  Further, the high-frequency currents idh and iqh supplied from the high-frequency current generator 405 can be expressed by the following expression (20) in fixed orthogonal coordinates.

  Further, the high-frequency current in the fixed orthogonal coordinates of the above equation (20) is expressed by the following equation (21), and the above equation (20) is substituted into this equation (21), and s = jωh (j is an imaginary unit) Then, the following formula (22) is obtained.

  As shown in the above equation (22), it can be seen that the rotor position information θ (= estimated position θp) is included in the amplitudes of the voltages Vαs and Vβs in the fixed orthogonal coordinates. Therefore, the amplitudes Vaα and Vaβ of the voltages Vαs and Vβs in fixed orthogonal coordinates are extracted by the Fourier transformer 410. Then, based on the amplitudes Vaα and Vaβ extracted by the Fourier transformer 410, a term including only the rotor position information θ is extracted by performing an operation as shown in the following equation (23).

  In order to realize this calculation, only the information on the rotor position θ is obtained by subtracting (Vaβ · Vaβ) from the output (Vaα · Vaα) of the multipliers 411 and 411 that square the amplitudes Vaα and Vaβ, respectively. A subtractor 412 that outputs ΔVαβ is used.

  The position calculator 413 calculates θ (estimated position θp) by calculating the inverse cosine of cos 2θ included in the above equation (23). The calculation of the estimated position θp is not an inverse cosine calculation, but a table storing the value of cos2θ may be prepared, and the estimated position θp may be obtained based on the value of cos2θ stored as a table in the storage device.

  The amplitude of cos 2θ included in the above equation (23) is represented by the following equation (24).

  The larger the amplitude, the larger the variation of ΔVαβ with respect to the estimated position θp. As the variation of ΔVαβ is larger, the influence of the calculation resolution of the microcomputer or CPU used for the calculation of the control means 401 can be relatively reduced, so that the estimated position θp can be calculated more accurately and the position estimation accuracy can be improved.

  ΔVαβ is proportional to the square of the amplitude ih of the high-frequency current. Therefore, if ih is increased, ΔVαβ is also increased, and the estimated position θp can be calculated more accurately. However, loss in the winding of AC rotating machine 1, vibration and noise of AC rotating machine 1 increase.

  On the other hand, ΔVαβ is proportional to l. Since l is proportional to the difference between the d-axis inductance Ld and the q-axis inductance from the above equation (1), ΔVαβ increases as the saliency increases, and the estimated position θp can be calculated more accurately.

  Therefore, in the second embodiment, the frequency fih (fih = reciprocal number of Tih in FIG. 12) of the high-frequency current commands idh * and iqh * generated by the high-frequency current generator is an extremal value. The frequency fh or near fh is set, and a current near the frequency fh or fh is supplied from the power feeding means 3. Thereby, the voltage including the component of the frequency fh is applied to the AC rotating machine 1.

  Considering that the power is a product of voltage and current, the power supply means 3 supplies the AC rotating machine 1 with power at the frequency fh at which the function including the inductance is an extreme value in addition to the power at the fundamental frequency. As a result, in addition to the fundamental frequency, the power necessary to obtain the desired estimated position accuracy of the AC rotating machine 1 can be reduced as compared with the case where power in a frequency band other than the frequencies fh and fh is supplied. The loss, vibration, and noise generated in the AC rotating machine 1 can be reduced.

  As described above, according to the second embodiment, as in the first embodiment, the power having the frequency at which the function including the inductance becomes an extreme value or near the extreme value and the power of the fundamental frequency are supplied to the AC rotating machine. By supplying power, the AC rotating machine can be stably driven with less power. As a result, it is possible to realize an AC rotating machine control device and an AC rotating machine control method that reduce vibration and noise during driving.

  In the second embodiment described above, the high-frequency current command values idh * and iqh * are added to the current commands id * and iq *, and are estimated by the position estimation unit 402 based on the voltages Vαs and Vβs at fixed orthogonal coordinates. The position θp was estimated. However, the means for calculating the estimated position θp is not limited to this, and the high frequency current command value of the frequency at which the function including the inductance of the AC rotating machine takes the extreme value is added to the current command value, and the AC rotating machine Anything that estimates the rotor position based on the voltage of 1 is included in the present invention.

Embodiment 3 FIG.
FIG. 14 is a block diagram showing a configuration of the entire system including a control device for an AC rotating machine according to Embodiment 3 of the present invention. The control apparatus for an AC rotating machine in the present third embodiment is configured as a control unit 501, and, similar to the first and second embodiments, based on the detection result by the current detection unit 2, the power feeding unit 3. The AC rotating machine 1 is controlled by supplying desired power via the.

  In FIG. 14, components having the same functions as those in the block diagram of FIG. 1 representing the configuration in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Next, a detailed configuration of the control unit 501 will be described. The control means 501 includes a three-phase / two-phase converter 4, a d-axis current controller 6, a q-axis current controller 7, a two-phase / three-phase converter 9, an adder 10, a position estimating means 102, a subtractor 103, The high-frequency voltage generator 104, the position correction unit 502, the adder 503, the coordinate converter 505, and the coordinate converter 508 are configured.

The position correction unit 502 receives the d-axis current id and the q-axis current iq, which are outputs from the coordinate converter 505, and outputs a position correction θh. The operation of the position correction unit 502 will be described later.
The adder 503 outputs the sum θp2 of the output θp of the position estimation unit 102 and the output θh of the position correction unit 502.

  The coordinate converter 508 uses the rotor position θp2 output from the adder 503 to convert the d-axis voltage command value Vd * and the q-axis voltage command value Vq * to a voltage command value on a fixed biaxial (α-β axis). Convert to Vα * and Vβ *.

  The coordinate converter 505 converts iαs and iβs into rotating biaxial (dq axis) currents id and iq using the rotor position θp2 output from the adder 503.

  Next, the position correction unit 502 will be described in detail. FIG. 15 is a diagram showing the relationship between the rotor position of the AC rotating machine 1 and the inductance when the AC rotating machine 1 according to Embodiment 3 of the present invention is loaded (when a current of a basic frequency is energized). In FIG. 6 shown above, the first inductance value L1 is taken at the rotor positions 90 degrees and 270 degrees, and L1 is equal to the q-axis inductance Lqh, and the second inductance is obtained at the rotor positions 0 and 180 degrees. Taking the value L2, L2 was equal to the d-axis inductance Ldh. However, in FIG. 15 according to the third embodiment, the second inductance L2 is shifted from the d-axis (rotor position 0 degree) by Δθ, and Ldh and L2 take different values.

  Similarly, the q-axis inductance Lqh and the first inductance value L1 take different values. This is due to the fact that the stator core 201 of the AC rotating machine 1 undergoes magnetic saturation by energizing the AC rotating machine 1 during loading.

  Hereinafter, the principle that an estimation error of the rotor position occurs due to the positional deviation amount Δθ will be described. In the above equation (1), the inductances Lα, Lβ, and Lαβ when there is a positional deviation amount Δθ are expressed as the following equation (25).

  When the above equation (25) is substituted into the above equation (3) and the same calculation as the above equations (4) to (7) is executed, ΔIαβ becomes the following equation (26).

  When the estimated position θp is calculated by calculating the inverse cosine of cos 2θ included in the above expression (26), the estimated position θp becomes the following expression (27), and the estimated position θp is a position relative to the rotor position θ. Deviation Δθ occurs.

  Therefore, the position correction means 502 utilizes the fact that the positional deviation amount Δθ depends on the current of the fundamental frequency energized in the AC rotary machine 1, and the positional deviation amount Δθ from the d-axis current id and the q-axis current iq. Is stored in advance by a method such as tabulating or using Δθ as a function of current, and the d-axis current id and q-axis current iq output from the coordinate converter 505 are input, and the positional deviation amount Δθ is stored. Is calculated and output.

  Note that the d-axis current id and the q-axis current iq input to the position correction unit 502 are input from the coordinate converter 505 in FIG. However, a current obtained by reducing or removing a high-frequency component with a low-pass filter may be input to the d-axis current id and q-axis current iq that are the outputs of the coordinate converter 505. In this case, since the high frequency current is reduced or removed, the same frequency component as the high frequency current included in θh that is the output of the position correction means 502 is reduced or removed, so that the position correction θh with respect to the fundamental frequency can be more accurately detected. Arithmetic can be performed.

  In the third embodiment, the position correction θh is calculated and output based on the d-axis current id and the q-axis current iq. However, since the positional shift amount Δθ depends on the current supplied to the AC rotating machine 1, the positional deviation amount Δθ is based on the current of the fundamental frequency flowing in the AC rotating machine 1 or the current including the fundamental wave frequency flowing in the AC rotating machine 1. Thus, the position correction θh may be calculated and output.

  For example, at least one of the currents iu and iv detected from the current detection means 2, the outputs iαs and iβs of the three-phase / two-phase converter 4, the d-axis current command, the q-axis current command, and the current command values id * and iq * Based on the above, the position correction θh may be calculated and output.

  As described above, according to the third embodiment, by providing the position correction unit, it is possible to correct the positional deviation amount Δθ of the position estimation unit accompanying magnetic saturation when the AC rotating machine is loaded. . As a result, good driving performance can be obtained even when the AC rotary machine is driven by a load.

  Needless to say, the position correction unit 502 according to the third embodiment can be applied to the correction of θp of the position estimation unit 402 when the AC rotating machine 1 is loaded in the second embodiment.

  In the first to third embodiments, the surface magnet type synchronous rotating machine has been described as the AC rotating machine 1. However, the present invention can be implemented by attaching the conductor 306 shown in FIG. 5 to the rotor of an embedded magnet type synchronous rotating machine or induction rotating machine.

  By attaching a conductor 306 as shown in FIG. 5 to the rotor of an embedded magnet type synchronous rotator or induction rotator, the inductance has frequency characteristics, and the function including the inductance has an extreme value. The saliency increases as compared with the case where no conductor is disposed. As a result, by supplying electric power of that frequency, an embedded magnet type synchronous rotating machine or induction rotating machine can be stably driven with less electric power.

  1 AC rotating machine, 2 current detection means, 3 power feeding means (power feeding section), 4 three-phase / two-phase converter, 5 coordinate converter, 6 d-axis current controller, 7 q-axis current controller, 8 coordinates Converter, 9 two-phase / three-phase converter, 10 adder, 20 Fourier transformer, 21 multiplier, 22 subtractor, 23 position calculator, 101 control means (control unit), 102 position estimation means, 103 subtractor , 104 high frequency voltage generator, 201 stator core, 202 armature winding, 204 permanent magnet, 206, 206a conductor, 207 magnetic flux, 303 rotor core, 304 permanent magnet, 305 shaft, 306 conductor, 308 conductor, 401 control Means (control unit), 402 Position estimation means, 403 Adder / Subtractor, 405 High-frequency current generator, 410 Fourier transformer, 411 multiplier, 412 Subtractor, 41 3 position calculator, 501 control means (control unit), 502 position correction means, 503 adder, 505 coordinate converter, 508 coordinate converter.

Claims (10)

A control device for an AC rotating machine including a control unit that supplies desired power to an AC rotating machine having frequency characteristics in inductance via the power feeding unit,
The control unit supplies power of a frequency at which a function including the inductance of the AC rotating machine has an extreme value and power of a fundamental frequency to the AC rotating machine via the power feeding unit. Control of the AC rotating machine apparatus. In the control device for an AC rotating machine according to claim 1,
The AC rotating machine has a first inductance and a second inductance, and at least one of the first inductance and the second inductance has a frequency characteristic,
The control unit uses a function constituted by the first inductance and the second inductance as a function including the inductance. In the control device for an AC rotating machine according to claim 2,
The control unit uses a function constituted by a difference between the reciprocal of the second inductance and the reciprocal of the first inductance as a function including the inductance. In the control device for an AC rotating machine according to claim 2,
The control unit uses a function constituted by a difference between the first inductance and the second inductance as a function including the inductance. In the control device for an AC rotating machine according to claim 2,
The control unit uses a function configured by a ratio of the first inductance and the second inductance as a function including the inductance. In the control device for an AC rotating machine according to any one of claims 2 to 5,
The rotor of the AC rotating machine has a permanent magnet having a conductor disposed around it, and a difference occurs between the first inductance and the second inductance due to an eddy current flowing through the conductor. Control device. In the control device for an AC rotating machine according to any one of claims 1 to 6,
The controller is configured to determine an estimated position of the AC rotating machine based on a current flowing through the AC rotating machine by applying a voltage having a frequency at which the function including the inductance is an extreme value through the power feeding unit. What is the controller for an AC rotating machine? In the control device for an AC rotating machine according to any one of claims 1 to 6,
The controller is configured to estimate the AC rotating machine based on a voltage applied to the AC rotating machine by energizing a current having a frequency at which the function including the inductance has an extreme value through the power feeding unit. A control device for an AC rotary machine that determines the position. In the control device for an AC rotating machine according to claim 7 or 8,
The control unit corrects the estimated position according to the current of the fundamental frequency. A control method for an AC rotating machine comprising a control unit that supplies desired power to an AC rotating machine having frequency characteristics in inductance via a power feeding unit,
The control unit includes a step of supplying the AC rotating machine with power having a frequency at which the function including the inductance of the AC rotating machine has an extreme value and power having a fundamental frequency are supplied to the AC rotating machine through the power feeding unit. How to control the machine.

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