Rotating machine control device

Abstract

A control apparatus (100) comprises: an electric current detection unit (2) for detecting a rotating machine electric current flowing in a rotating machine (1); a position estimation unit (4) for calculating an estimated value of a rotor position which is positional information relating to a rotor (1b), on the basis of the rotating machine electric current; an electric current control unit (5) for generating a first voltage command which is a command value of a rotating machine voltage for driving the rotating machine (1), on the basis of the detected value of the rotating machine electric current and the estimated value of the rotor position; a position estimation voltage generation unit (30) for generating a position estimation voltage for estimating the rotor position on the basis of a torque axis electric current command which is a physical quantity having correlation with magnetic saturation of a rotor (1b), the position estimation voltage having a higher frequency than the first voltage command; and a voltage applicator (3) for applying a driving voltage to the rotating machine (1) on the basis of a second voltage command obtained by superimposing the position estimation voltage on the first voltage command.

Description

[Technical field]

[0001] The present disclosure relates to a control device for a rotating machine that obtains rotor position information and performs control without using a position sensor that detects the rotor position. [Background technology]

[0002] In order to drive a rotating machine while fully utilizing its performance, rotor position information is necessary. For this reason, rotating machines have been driven using position information detected by a position sensor attached to the rotating machine. On the other hand, in recent years, from the viewpoints of further reducing the manufacturing cost of rotating machines, reducing the size of rotating machines, and improving the reliability of rotating machines, technologies for driving rotating machines without a position sensor have been developed.

[0003] In position sensorless control of a rotating machine, a method of estimating the rotor position of a rotating machine from the induced voltage of the rotating machine and a method of estimating the rotor position of a rotating machine using saliency are used together or separately depending on the speed range. The former is used in high-speed ranges where the induced voltage required for position estimation is sufficient, and the latter is used in low-speed ranges where a sufficient induced voltage is not available.

[0004] As a conventional technique for estimating the rotor position of a rotating machine using saliency as in the latter case, for example, Patent Document 1 below discloses a technique for applying to a rotating machine a high-frequency voltage having a frequency higher than the fundamental frequency superimposed on a drive voltage. Specifically, in Patent Document 1, a high-frequency current vector, the locus of which is an ellipse, is separated into a positive-sequence current vector and a mirror-sequence current vector, and the rotor position is detected by calculating the intermediate angle between the two vectors. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-171799 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, even if the technology of Patent Document 1 is used, when the salient pole ratio of a rotating machine is structurally small, the trajectory of the high-frequency current vector does not become a clear ellipse depending on the rotating machine current, and the problem remains that the detection accuracy of the rotor position decreases.

[0007] The present disclosure has been made in consideration of the above, and aims to provide a control device for a rotating machine that can suppress a decrease in the detection accuracy of the rotor position even when the salient pole ratio of the rotating machine is structurally small. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, a control device for a rotating machine according to the present disclosure includes a current detection unit, a position estimation unit, a current control unit, a position estimation voltage generation unit, and a voltage applicator. The current detection unit detects a rotating machine current flowing through the rotating machine. The position estimation unit calculates an estimate of a rotor position, which is position information of a rotor of the rotating machine, based on the rotating machine current. The current control unit generates a first voltage command, which is a command value of a rotating machine voltage for driving the rotating machine, based on the detected value of the rotating machine current and the estimate of the rotor position. The position estimation voltage generation unit generates a high-frequency voltage having a higher frequency than the first voltage command, which is a position estimation voltage for estimating the rotor position, based on a physical quantity correlated with the magnetic saturation of the rotor. The voltage applicator applies a driving voltage to the rotating machine based on a second voltage command obtained by superimposing the position estimation voltage on the first voltage command. Effect of the Invention

[0009] According to the control device for a rotating machine according to the present disclosure, it is possible to suppress a decrease in detection accuracy of the rotor position even when the salient pole ratio of the rotating machine is structurally small. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration example of a control device for a rotating machine according to a first embodiment; [Diagram 2] FIG. 2 is a diagram showing an example of a waveform of a high-frequency voltage output from a position estimation voltage generating unit in FIG. 1; [Diagram 3] FIG. 1 is a cross-sectional view used to explain a structure of a rotor core in a reluctance type rotating machine assumed in the first embodiment. [Figure 4] Diagram showing the change in inductance in a typical reluctance type rotating machine [Diagram 5] FIG. 4 is a diagram showing an example of a current vector locus when a high-frequency current is applied to a rotating machine having the rotor core shown in FIG. 3. [Figure 6] The magnetic flux flow caused by the high-frequency current components when the fundamental current components are small is shown in the rotor core in Fig. 3. [Figure 7] FIG. 1 is a diagram showing an example of a coefficient value table used in high frequency boost control according to the first embodiment; [Figure 8] FIG. 1 is a first diagram for explaining the effect of high frequency boost control according to the first embodiment; [Figure 9] FIG. 2 is a second diagram for explaining the effect of the high frequency boost control according to the first embodiment; [Figure 10] FIG. 13 is a diagram showing a configuration example of a control device for a rotating machine according to a second embodiment; [Figure 11] FIG. 1 is a diagram showing a first example of a hardware configuration for implementing each function of a control device according to a first embodiment and a second embodiment; [Figure 12] FIG. 13 is a diagram showing a second example of a hardware configuration for implementing each function of the control device according to the first and second embodiments; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a rotating machine control device according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0012] Embodiment 1 Fig. 1 is a diagram showing an example of the configuration of a rotating machine control device (hereinafter, appropriately abbreviated as "control device") 100 according to the first embodiment. The control device 100 according to the first embodiment is configured to include a current detection unit 2, a voltage applicator 3, a position estimation unit 4, a current control unit 5, a DC power supply 12, and a position estimation voltage generation unit 30. In Fig. 1, the current control unit 5 is a controller of a current control system, and the position estimation unit 4 and the position estimation voltage generation unit 30 are controllers of a rotor position estimation system.

[0013] The rotating machine 1 is a device driven by the control device 100. The rotating machine 1 has a stator 1a and a rotor 1b arranged inside the stator 1a. In this document, a reluctance type rotating machine is assumed as an example of the rotating machine 1, but is not limited to this. The rotating machine 1 may be, for example, an embedded magnet type rotating machine.

[0014] A DC power source 12 supplies DC power to the voltage applicator 3. When the rotating machine 1 is a motor, the voltage applicator 3 applies a DC voltage V dc is used to generate an AC voltage for driving the motor, and the generated AC voltage is applied to the motor.

[0015] The current detection unit 2 detects the rotating machine current i flowing between the voltage application device 3 and the rotating machine 1. u ,i v ,i w Detect the rotating machine current i u ,i v ,i w is the stator current flowing through each phase of the stator 1a, i.e., the u-phase, v-phase, and w-phase. A current detector is provided for each phase of the current detection unit 2. One example of a current detector is a current transformer. In FIG. 1, the current detection unit 2 detects all three-phase currents, but this is not limited thereto. It is possible to detect the currents of any two of the three phases, and the remaining phase is a rotating machine current i u ,i v ,i w Alternatively, instead of the current detector 2 in FIG. 1, a bus current flowing through a DC bus connecting the voltage applicator 3 and the DC power source 12 may be detected, and the rotating machine current i u ,iv ,i w may be calculated.

[0016] The position estimation unit 4 estimates the rotating machine current i u ,i v ,i w Based on this, the estimated value θ of the rotor position, which is the position information of the rotor 1b, is calculated. L The current control unit 5 calculates the rotating machine current i u ,i v ,i w and the estimated rotor position θ L Based on the above, a first voltage command V u * ,V v * ,V w * The position estimation voltage generating unit 30 generates the q-axis current command i q * Based on this, the first voltage command V u * ,V v * ,V w * High frequency voltage V uh ,V vh ,V wh Generates a high-frequency voltage V uh ,V vh ,V wh is a voltage for position estimation for estimating the rotor position. The current control unit 5 outputs the first voltage command V u * ,V v * ,V w * to high frequency voltage V uh ,V vh ,V wh The superimposed voltage is the second voltage command V up * ,V vp * ,V wp * The voltage applicator 3 outputs the second voltage command V up * ,V vp* ,V wp * Based on this, a driving voltage is generated and applied to the rotating machine 1. In this paper, the voltage applicator 3 is assumed to be a two-level three-phase inverter, but is not limited to this. In this paper, the voltage applicator 3 may be a three-level three-phase inverter, or a polyphase two-level or three-level inverter.

[0017] The current control unit 5 includes subtractors 13d, 13q, a d-axis current controller 14d, a q-axis current controller 14q, a first coordinate converter 15, a two-phase to three-phase converter 16, a second coordinate converter 17, a three-phase to two-phase converter 18, and adders 23u, 23v, and 23w.

[0018] The subtractor 13d subtracts the d-axis current command i d * and the d-axis current i output from the second coordinate converter 17. d Deviation Δi d The next stage d-axis current controller 14d calculates the deviation Δi d By controlling the proportional integral so that d * The subtractor 13q calculates the q-axis current command i q * and the q-axis current i output from the second coordinate converter 17. q Deviation Δi q The next stage q-axis current controller 14q calculates the deviation Δi q By controlling the proportional integral so that q * Calculate the d-axis current command i d * is the d-axis current command value for driving the rotating machine 1, and the q-axis current command i q * is the command value of the q-axis current to drive the rotating machine 1. The d-axis current command i d * and q-axis current command i q * are both given from outside the current control unit 5.

[0019] The first coordinate converter 15 converts the d-axis voltage commands V d * and q-axis voltage command V q * The voltage command V α * ,V β * The two-phase to three-phase converter 16 converts the voltage command V α * ,V β * The first voltage command V u * ,V v * ,V w * In addition, the processing of the first coordinate converter 15 uses the estimated value θ of the rotor position output from the position estimation unit 4. L is used.

[0020] The three-phase to two-phase converter 18 converts the rotating machine current i u ,i v ,i w The α-axis current i on the stationary two-axis coordinate system α and β-axis current i β The second coordinate converter 17 converts the α-axis current i α and β-axis current i β is the estimated rotor position θ output from the position estimation unit 4. L The d-axis current i on the rotating coordinate system that rotates in sync with d and q-axis current i q and output them to subtractors 13d and 13q, respectively.

[0021] The first voltage command V output from the two-phase to three-phase converter 16 u * ,V v * ,V w * and the high-frequency voltage V output from the position estimation voltage generating unit 30. uh ,V vh ,Vwh The outputs of the adders 23u, 23v, and 23w are added together to form a second voltage command V up * ,V vp * ,V wp * Therefore, the second voltage command V up * ,V vp * ,V wp * The first voltage command V u * ,V v * ,V w * The high-frequency voltage V uh ,V vh ,V wh The high-frequency voltage V uh ,V vh ,V wh Details will be provided later.

[0022] The position estimation unit 4 includes current extractors 6u, 6v, and 6w, a high-frequency current amplitude calculation unit 7, and a position calculation unit 8. As described above, the second voltage command V up * ,V vp * ,V wp * The first voltage command V u * ,V v * ,V w * The high-frequency voltage V uh ,V vh ,V wh Therefore, the rotating machine current i detected by the current detection unit 2 u ,i v ,i w is the high frequency voltage V uh ,V vh ,Vwh High frequency current i with the same frequency component as uh ,i vh ,i wh Contains:

[0023] Therefore, each of the current extractors 6u, 6v, and 6w detects the rotating machine current i u ,i v ,i w From the high frequency voltage V uh ,V vh ,V wh High frequency current i with the same frequency component as uh ,i vh ,i wh Extract the high frequency current i uh ,i vh ,i wh A bandpass filter or a notch filter can be used to extract the rotating machine current i u ,i v ,i w is input to the notch filter to generate the high-frequency voltage V uh ,V vh ,V wh The same frequency components as the rotating machine current i u ,i v ,i w By subtracting each current after passing through the notch filter from uh ,i vh ,i wh can be extracted.

[0024] The high frequency current amplitude calculation unit 7 includes multipliers 9u, 9v, and 9w, integrators 10u, 10v, and 10w, and square root calculators 22u, 22v, and 22w. These components are provided corresponding to each phase.

[0025] In the multipliers 9u, 9v, and 9w, the high-frequency current i uh ,i vh ,i whThe autocorrelation value is calculated by squaring the integrators 10u, 10v, and 10w. The integrators 10u, 10v, and 10w perform integration processing for a time Tn of one integration period, and the integral value is multiplied by (2 / Tn) and output. The square root calculators 22u, 22v, and 22w calculate the square root of each output of the integrators 10u, 10v, and 10w to calculate the position estimation current amplitude I uh ,I vh ,I wh is required.

[0026] In addition, in the high-frequency current amplitude calculation unit 7 in FIG. uh ,i vh ,i wh The autocorrelation value of is integrated and the square root is calculated to obtain the position estimation current amplitude I uh ,I vh ,I wh However, it is not limited to this. High frequency current i uh ,i vh ,i wh The current amplitude I for position estimation is calculated by passing the autocorrelation value of uh ,I vh ,I wh You may ask for:

[0027] The position calculator 8 calculates the position estimation current amplitude I uh ,I vh ,I wh Based on this, the rotor position estimate θ L The rotor position estimate θ L A known method is used for the calculation of , and a detailed description thereof will be omitted here. Note that a specific calculation procedure is disclosed in, for example, Japanese Patent No. 5324646, and the contents of this publication should be referred to.

[0028] Next, the high-frequency voltage V output from the position estimation voltage generating unit 30 uh ,V vh ,V wh FIG. 2 shows the high-frequency voltage V output from the position estimation voltage generating unit 30 in FIG. uh ,V vh ,V wh2 is a diagram showing an example of the waveform of Fig. 2. Note that the waveform of Fig. 2 is an example in the case where the voltage applicator 3 is equipped with a PWM (Pulse Width Modulation) inverter for triangular wave comparison.

[0029] The horizontal axis of Fig. 2 represents time. In Fig. 2, from the top, the triangular wave carrier, the u-phase high-frequency voltage V uh , v-phase high-frequency voltage V vh , w-phase high-frequency voltage V wh The waveform of the high frequency voltage V uh ,V vh ,V wh One period Th of the high frequency voltage V is 6 periods (=6 Tc) when the half period Tc of the triangular wave carrier is one period. In the example of Figure 2, uh ,V vh ,V wh In order to achieve three-phase balance, the high-frequency voltage V is set to be shifted by two intervals (=2·Tc) between each phase. Note that FIG. 2 is an example, and the present invention is not limited to this example. uh ,V vh ,V wh Any waveform may be used as long as it results in three-phase balance.

[0030] Returning to FIG. 1, the position estimation voltage generating unit 30 will be described. The position estimation voltage generating unit 30 is configured to include a high frequency amplitude calculator 31 and a high frequency voltage generator 32. The high frequency amplitude calculator 31 receives a q-axis current command i q * The high-frequency amplitude calculator 31 receives the q-axis current command i q * Based on the coefficient value W h Select or calculate the coefficient value W h is the high frequency voltage V uh ,V vh ,V wh The coefficient value W is a positive real value that is set to determine the voltage amplitude of h The selection of the coefficient value W h Alternatively, the coefficient value W can be calculated by a function without using a table. h may be calculated.

[0031] In addition, the q-axis current command i q * is an example of a physical quantity that is correlated with the magnetic saturation of the rotor 1b. If the physical quantity is correlated with the magnetic saturation of the rotor 1b, the q-axis current command i q * Another example of a physical quantity that is correlated with the magnetic saturation of the rotor 1b is the q-axis current i q , q-axis voltage command V q * In addition, the d-axis current command i d * , d-axis current i d , d-axis voltage command V d * These can also be physical quantities correlated with the magnetic saturation of the rotor 1b.

[0032] The high frequency voltage generator 32 has a coefficient value W h Using the above-mentioned high-frequency voltage V uh ,V vh ,V wh The operation of the high frequency voltage generator 32 is explained using some equations shown below.

[0033] A mathematical formula expressing a high-frequency current will be derived to explain the operation of high-frequency voltage generator 32. First, the voltage equation of rotating machine 1 on the αβ axes, which are stationary coordinates, is expressed by the following formula (1).

[0034]

number

[0035] In the above formula (1), i α ,i β are the α-axis current and β-axis current mentioned above. Also, V α ,V β represent the α-axis voltage and the β-axis voltage, respectively. Also, R, K E represent the stator resistance and the induced voltage coefficient, respectively. Also, L α ,L β ,L αβ,L d ,L q respectively represent the α-axis inductance, the β-axis inductance, the mutual inductance between the α and β axes, the d-axis inductance, and the q-axis inductance. Furthermore, L0 is defined by the fifth equation in (1) above, and L1 is defined by the sixth equation in (1) above. Furthermore, p represents the differential operator.

[0036] The above formula (1) is applicable when the rotating machine 1 is a reluctance type synchronous machine. When the rotating machine 1 is a reluctance type synchronous machine that does not have a magnet, the induced voltage coefficient K E becomes zero, so the induced voltage coefficient K E It is possible to omit the second term of the above formula (1), which includes: Moreover, when only high-frequency components are considered in the above formula (1), the following formula (2) is obtained.

[0037]

number

[0038] In the above formula (2), V αh ,V βh ,i αh ,i βh represent the high frequency components of the α-axis voltage, β-axis voltage, α-axis current, and β-axis current, respectively. Note that by transforming the above formula (1) into the above formula (2), a similar formula can be obtained for a synchronous reluctance motor that does not use magnets. Therefore, it goes without saying that the above formula (2) is not limited to interior magnet type rotating machines.

[0039] When the above equation (2) is solved for the current differential term, the following equation (3) is obtained.

[0040]

number

[0041] In addition, the high-frequency voltage V on the αβ axis α ,V β is defined as the following equation (4).

[0042]

number

[0043] In the above formula (4), V hαβ represents the high frequency voltage amplitude on the αβ axis, and ω h represents the angular frequency on the αβ axis. Note that angular frequency is also called "angular velocity."

[0044] When the above formula (4) is expressed in three-phase coordinates, the default high-frequency voltage V is expressed by the following formula (5). uh1 ,V vh1 ,V wh1 is obtained.

[0045]

number

[0046] The high frequency voltage generator 32 outputs the coefficient value W h Use the default high frequency voltage V uh1 ,V vh1 ,V wh1 Coefficient value W h By multiplying this, the high frequency voltage V uh ,V vh ,V wh Generate.

[0047]

number

[0048] Next, the structure of the rotor core constituting the rotor 1b in the reluctance type synchronous machine will be described. FIG. 3 is a cross-sectional view used to explain the structure of a rotor core 50 in a reluctance type rotating machine assumed in the first embodiment. In FIG. 3, the rotor core 50 is formed by laminating a plurality of electromagnetic steel sheets, which are plate materials. A shaft 51 is fitted to the inner diameter side of the rotor core 50. The rotor core 50 is formed of a laminated body in which core pieces 53, which are annular thin plates, are laminated. The core pieces 53 can be made by punching out electromagnetic steel sheets, which are thin steel plates, with a press machine. In a state in which the rotating machine 1 is assembled, the lamination direction of the thin plates constituting the rotor core 50 is the same as the axial direction of the shaft 51.

[0049] A rotor core 50 in which a number of core pieces 53 are laminated has a number of slits 52 that form flux barriers. The slits 52 are arc-shaped and protrude toward the shaft hole side into which the shaft 51 fits, and are formed from one d-axis side to the other d-axis side with the q-axis as the center. In the rotor core 50, the d-axis is an axis through which magnetic flux can pass relatively easily, and the q-axis is an axis through which magnetic flux cannot pass relatively easily. The d-axis and the q-axis are magnetically and electrically perpendicular to each other.

[0050] Slit groups 54 each consisting of a plurality of slits 52 are formed at intervals in the circumferential direction of rotor core 50, the number of which corresponds to the number of poles. Fig. 3 shows an example in which rotor 1b has four poles, and in Fig. 3, slit groups 54 for four poles are formed.

[0051] The rotor core 50 must have enough strength to withstand the centrifugal force when the rotating machine 1 rotates. For this reason, the slit 52 located at the outermost periphery is formed with a center rib 55a that acts as a strength member. In addition to the center rib 55a, each slit 52 other than the outermost periphery is formed with two side ribs 55b that also act as strength members. The center rib 55a and the side rib 55b can be formed by leaving the center rib 55a and the side rib 55b unpunched when punching out the thin steel plate to form the slit 52. The arrangement of the center rib 55a and the side rib 55b shown in FIG. 3 is an example, and is not limited to these arrangements. Any arrangement may be used as long as the desired strength is obtained.

[0052] Furthermore, in rotor core 50, between each group of slits 54 and edge 56 on the outer periphery of rotor core 50, there is an annular portion where no slits are formed. In this document, this portion is referred to as the "annular portion." In rotor core 50, the annular portion also acts as a strength member. In this document, strength members such as center rib 55a, side rib 55b, and the annular portion that act as strength members are sometimes collectively referred to as the "bridge portion."

[0053] In the fifth and sixth equations of the above (1), the d-axis inductance L d and the q-axis inductance L q Figure 4 shows the change in inductance in a typical reluctance type rotating machine. The horizontal axis represents the rotor position, and the vertical axis represents the magnitude of inductance.

[0054] In a typical reluctance type rotating machine, the inductance changes according to the electrical angle. Specifically, as shown in Fig. 4, the inductance has a characteristic that the maximum value and the minimum value appear twice during one electrical rotation. The maximum value of the inductance is the d-axis inductance L d The minimum value of inductance is the q-axis inductance L q That is, the d-axis inductance L d teeth 、q-axis inductance L q Here, the d-axis inductance L d q-axis inductance L q If the ratio of these is defined as the saliency ratio, then the saliency ratio L q / L d is greater than 1. This is because the d-axis current i d The q-axis current i q This is because the rotating machine 1 is configured so that the interlinkage magnetic flux due to the axial direction is larger than that due to the axial direction.

[0055] 5 is a diagram showing an example of a current vector locus when a high-frequency current flows through a rotating machine having the rotor core 50 shown in FIG. 5. The horizontal axis of FIG. 5 represents the d-axis current i d The vertical axis represents the q-axis current i q As shown in FIG. 5, the q-axis current i q When is relatively large, the current vector locus becomes elliptical. On the other hand, the q-axis current i q When is small, as shown in the lower left, the current vector locus is not elliptical but is almost circular. The center of the current vector locus represents the fundamental wave current component of the current flowing through the rotating machine 1, and the distance from the center of each plot of the current vector locus represents the high frequency current component of the current flowing through the rotating machine 1. Therefore, the q-axis current i q A region where this is small means that the torque command given to the rotating machine 1 is small.

[0056] When the current vector locus is elliptical, the rotor position can be detected from the directions of the major and minor axes of the ellipse. In contrast, when the current vector locus is not elliptical, it is difficult to distinguish between the major and minor axes, and therefore the rotor position cannot be detected with high accuracy. The reason for this will be explained with reference to Fig. 6. Fig. 6 is a diagram showing the flow of magnetic flux generated by the high-frequency current components when the fundamental current components are small, in rotor core 50 shown in Fig. 3.

[0057] In FIG. 6, the solid arrow indicates the q-axis current i qThis represents the flow of magnetic flux that can be generated by the high-frequency current components included in the d-axis current i. In this paper, this magnetic flux component is called the "torque flux" for convenience. The dashed arrow indicates the d-axis current i d This represents the flow of magnetic flux that can be generated by the components of the high-frequency current contained in the axial direction. In this paper, this magnetic flux component is referred to as the "excitation magnetic flux" for convenience. As mentioned above, the rotor core 50 shown in FIG. 3 has a structure with saliency. For this reason, during steady-state operation when the fundamental current component is large, the bridge section of the rotor core 50 is sufficiently magnetically saturated, so the q-axis magnetic flux indicated by the solid arrow becomes small. In contrast, when the fundamental current component is small, the degree of magnetic saturation in the bridge section is low, so the torque magnetic flux passing through the bridge section does not attenuate much. For this reason, the torque magnetic flux passing through the bridge section becomes large, the difference with the excitation magnetic flux becomes small, and the saliency does not appear.

[0058] The control device 100 according to the first embodiment shown in FIG. 1 is configured to solve the problem related to the above-mentioned saliency. Specifically, the control device 100 calculates an estimated rotor position θ L Regarding the above, if the desired detection accuracy is not obtained, the coefficient value W calculated by the high frequency amplitude calculator 31 is h is controlled in the increasing direction to increase the high frequency voltage V uh ,V vh ,V wh In this paper, for convenience, this control is called "high frequency boost control."

[0059] Considering the case where there is no high-frequency current, when the fundamental current is small, the magnetic flux component passes through the bridge section easily. If the width of the bridge section is narrowed, the amount of magnetic flux passing through is reduced, but the strength of the rotor core 50 is weakened. Also, if the fundamental current is increased, the bridge section is magnetically saturated. However, this method causes unnecessary current to flow, which reduces efficiency and applies unnecessary torque to the rotating machine 1, which is undesirable in terms of operation. In contrast, if the high-frequency current is increased, the bridge section can be magnetically saturated without changing the magnitude of the fundamental current. This makes it possible to solve the problem of the fundamental current making it difficult for saliency to appear by control.

[0060] The specific processing is as described above. The coefficient value W h Calculate the default high frequency voltage V uh1 ,V vh1 ,V wh1 Coefficient value W h By multiplying by uh ,V vh ,V wh Also, the coefficient value W h A table can be used to calculate the coefficient value table 7. FIG 7 is a diagram showing an example of a coefficient value table used in the high frequency boost control according to the first embodiment.

[0061] In FIG. 7, the coefficient value table has a table head with the d-axis current command i d * Current value i d1 * ,i d2 * ,i d3 * ,…,i dM * The coefficient value table shows the q-axis current command i q * Current value i q1 * ,i q2 * ,i q3 * ,…,iqN * The current value i d1 * ,i d2 * ,i d3 * ,…,i dM * The interval between the current values ​​i does not have to be equal, but may be unequal. q1 * ,i q2 * ,i q3 * ,…,i qN * The same applies to.

[0062] The coefficient value table contains the d-axis current command i d * and q-axis current command i q * The coefficient value W is determined by the relationship h The value of (W h11 ,W h12 ,W h13 ,…,W h1M ,W h21 ,W h22 ,W h23 ,…,W h2M ,W h31 ,W h32 ,W h33 ,…,W h3M ,…,W hN1 ,W hN2 ,W hN3 ,…,W hNM ) is stored. Note that the current value i q1 * ,i q2 * ,i q3 * ,…,i qN * i q1 * q2 * q3 * <,…, qN * If W h11 ,W h21 ,W h31 ,…,W​​​hN1 Between h11 >W h21 >W h31 >,…,>W hN1 That is, the coefficient value W h is the q-axis current command i q * There is a negative correlation with the coefficient values ​​of other columns W h The same is true for the current value i d1 * ,i d2 * ,i d3 * ,…,i dM * i d1 * d2 * d3 * <,…, dM * If W h11 ,W h12 ,W h13 ,…,W h1M Between h11 >W h12 >W h13 >,…,>W h1M That is, the coefficient value W h is the d-axis current command i d * There is a negative correlation with the coefficient values ​​W h The same is true.

[0063] The values ​​stored in the coefficient value table can be obtained by simulation. It is not necessary to obtain all the stored values ​​by simulation, and the values ​​may be obtained by calculation processing such as interpolation processing, extrapolation processing, or interpolation processing of some simulation results.

[0064] Next, the coefficient value W in the high frequency boost control according to the first embodiment h First, in the coefficient value table in FIG. 7, the part surrounded by a thick frame is set as the default. Here, i d1 * ​​​= 0. The high-frequency amplitude calculator 31 calculates the q-axis current command i q * Based on this, the coefficient value W h For example, the q-axis current command i q * The value of i q3 * ", then "W h31 ". q-axis current command i q * The value of i q2 * " and "i q3 * If the value is between i q2 * " and "i q3 * " may be selected.

[0065] In addition, the q-axis current command i q * In addition, the d-axis current command i d * In this case, the entire coefficient value table in FIG. 7 is used. For example, the q-axis current command i q * The value of i q3 * " and the d-axis current command i d * The value of i d2 * ", then "W h32 If the coefficient value is not included in the coefficient value table, it goes without saying that it may be found by interpolation or the like.

[0066] Next, the effect of the high frequency boost control according to the first embodiment will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a first diagram for explaining the effect of the high frequency boost control according to the first embodiment. Fig. 9 is a second diagram for explaining the effect of the high frequency boost control according to the first embodiment.

[0067] The horizontal axis of Fig. 8 is the d-axis current id The vertical axis represents the q-axis current i q Also, on the left side of Fig. 8, the q-axis current i q = 0 and d-axis current i d The current vector locus when = 0 is the coefficient value W h But, W h =0.1, W h = 0.3 and W h The right side of FIG. 8 shows the case where the same three coefficient values ​​W h For the q-axis current i q = 0 and d-axis current i d The current vector locus when the coefficient value W h Regarding the DC voltage V of the DC power supply 12, dc The coefficient value W h The criteria are not limited to this example, and may be determined based on any criteria.

[0068] In addition, in FIG. 9, the theoretical value of the rotor position is shown by a dashed line along with the waveforms of the u-phase current and the v-phase current, and the estimated value θ L The upper side (a) is W h The waveform when W = 0.1 is shown in the lower part (b). h This is the waveform when =0.3.

[0069] According to Figure 8, W h When W = 0.1, the current vector locus is not an ellipse. h = 0.3 and W h When = 0.5, the current vector locus is an ellipse. This tendency is also seen when the d-axis current i d It has also been shown that it does not depend on

[0070] The above results are consistent with the explanation given above. For example, W hWhen θ = 0.1, the center rib 55a and the side rib 55b of the rotor core 50 are not magnetically saturated, so the torque magnetic flux passing through the center rib 55a and the side rib 55b becomes large and no saliency appears. As a result, the current vector locus does not become an ellipse. As a result, as shown in FIG. 9(a), the estimated value θ of the rotor position L The waveform of the signal becomes unstable, and sufficient estimation accuracy cannot be obtained.

[0071] In contrast, W h = 0.3 and W h When θ = 0.5, the center rib 55a and the side rib 55b of the rotor core 50 are magnetically saturated by the high-frequency current, so that the torque magnetic flux passing through the center rib 55a and the side rib 55b becomes small and saliency appears, and the current vector locus becomes an ellipse. L The waveform of is stable, and sufficient estimation accuracy can be obtained.

[0072] In the above, the control and operation when the high frequency boost control according to the first embodiment is applied to the rotor core 50 having the structure shown in FIG. 6 has been described, but the present invention is not limited to this example and can be applied to rotor cores having various structures. The high frequency boost control according to the first embodiment can also be applied to rotor cores having an extremely small saliency ratio. For example, when the saliency ratio of the rotor core is small, a larger coefficient value W can be used according to the degree of the saliency ratio. h By selecting the above and setting the high frequency voltage amplitude, the rotor position can be detected.

[0073] However, the coefficient value W h Increasing the value of θ means increasing the rotating machine current. L Therefore, the estimated value θ L The smallest possible coefficient value W h For example, in the example of Figure 8, W hIt is desirable to select a coefficient value of W = 0.3. By using a table such as that shown in FIG. h It becomes possible to select

[0074] As described above, in the rotating machine control device according to the first embodiment, the current control unit generates a first voltage command, which is a command value of the rotating machine voltage for driving the rotating machine, based on the detected value of the rotating machine current and the estimated value of the rotor position. Then, the position estimation voltage generating unit generates a position estimation voltage for estimating the rotor position, based on a physical quantity correlated with the magnetic saturation of the rotor, and a high-frequency voltage having a higher frequency than the first voltage command. This makes it possible to suppress a decrease in detection accuracy of the rotor position even when the salient pole ratio of the rotating machine is structurally small.

[0075] In the above configuration, the position estimation voltage generating unit includes a high frequency amplitude calculator that calculates a coefficient value for determining the voltage amplitude of the high frequency voltage based on a physical quantity that is correlated with magnetic saturation. The high frequency amplitude calculator generates the position estimation voltage using the coefficient value. This makes it possible to easily realize the configuration of the control device.

[0076] In the above, the physical quantity correlated with the magnetic saturation of the rotor may be a torque axis current command given to the current control unit, or a torque axis current command and an excitation axis current command given to the current control unit. The torque axis current command and the excitation axis current command are parameters used inside the control device, so that the configuration of the control device can be realized more simply.

[0077] Furthermore, according to the control device for a rotating machine according to the first embodiment, when the estimated value of the rotor position is not detected with the desired accuracy, the coefficient value that determines the voltage amplitude is controlled to increase, making it possible to set the coefficient value corresponding to the desired detection accuracy while suppressing an increase in the high-frequency current.

[0078] Moreover, according to the control device for a rotating machine according to the first embodiment, the rotor position can be detected even in a state in which the torque axis current and the excitation axis current are zero. This makes it possible to stably estimate the rotor position while improving the operating efficiency of the rotating machine.

[0079] Embodiment 2 Fig. 10 is a diagram showing a configuration example of a control device 100A for a rotating machine according to embodiment 2. Comparing the control device 100A according to embodiment 2 with the control device 100 shown in Fig. 1, in Fig. 10, the current control unit 5 is replaced with a current control unit 5A. Also, in the current control unit 5A, a fundamental wave current extractor 11 is added to the configuration of the current control unit 5 shown in Fig. 1. The other configurations are the same or equivalent to those of the control device 100, and the same or equivalent components are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0080] As described above, a high-frequency current consisting of a superimposed frequency component and a sideband component is a disturbance to the current control system, so it is desirable that the superimposed frequency is sufficiently far from the response frequency of the current control system. On the other hand, in order to secure calculation time and reduce noise, the superimposed frequency may be set to a lower frequency, and the response frequency of the current control system and the superimposed frequency may be set closer to each other, which adversely affects the processing of the current control system. Also, as described above, in applications where the rotation speed of a rotating machine is high, the sideband components are distributed over a wide area, which adversely affects the processing of the current control system.

[0081] Therefore, in the second embodiment, the high-frequency voltage V uh ,V vh ,V wh In order to remove or reduce the influence of high frequency current caused by the application of the fundamental wave current extractor 11, the fundamental wave current extractor 11 is disposed between the current detection unit 2 and the three-phase to two-phase converter 18, that is, in the previous stage of the three-phase to two-phase converter 18, as shown in FIG.

[0082] The fundamental wave current extractor 11 extracts the rotating machine current i detected by the current detection unit 2. u ,i v ,i wFrom the high frequency voltage V uh ,V vh ,V wh The fundamental current i with the same frequency components removed or attenuated uf ,i vf ,i wf Extract the fundamental current i uf ,i vf ,i wf A low-pass filter or a notch filter can be used to extract the fundamental current i uf ,i vf ,i wf is used as an input signal and the processing described in the first embodiment is performed. The subsequent processing is the same as that described in the first embodiment.

[0083] According to the control device 100A of the second embodiment, in the processing of the current control unit 5A which is a current control system, the rotating machine current i u ,i v ,i w From the above, the high frequency current i uh ,i vh ,i wh In this way, the superimposed frequency components and their sideband components are sufficiently removed, thereby making it possible to suppress adverse effects on the current control system, such as response degradation or instability.

[0084] As described above, in the rotating machine control device according to the second embodiment, the fundamental wave component extractor extracts the fundamental wave component by removing the harmonic superimposition components contained in the detected value of the rotating machine current. Then, the current control unit generates a first voltage command based on the output of the fundamental wave component extractor and the estimated value of the rotor position. This provides the effect of reliably preventing adverse effects on the current control system, such as response degradation or instability.

[0085] Next, the hardware configuration of the control device 100, 100A according to the above-described first and second embodiments will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a diagram showing a first hardware configuration example for realizing each function of the control device 100, 100A according to the first and second embodiments. Fig. 12 is a diagram showing a second hardware configuration example for realizing each function of the control device 100, 100A according to the first and second embodiments. Note that the functions of the control device 100, 100A refer to the functions of the position estimation unit 4, current control units 5, 5A, and position estimation voltage generation unit 30 included in the control device 100, 100A.

[0086] The functions of the position estimation unit 4, the current control units 5 and 5A, and the position estimation voltage generation unit 30 can be realized by using a processing circuit. In FIG. 11, the position estimation unit 4, the current control units 5 and 5A, and the position estimation voltage generation unit 30 in the first and second embodiments are replaced with a dedicated processing circuit 40. When dedicated hardware is used, the dedicated processing circuit 40 corresponds to a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these. The functions of the position estimation unit 4, the current control units 5 and 5A, and the position estimation voltage generation unit 30 may be realized individually by a processing circuit, or may be realized collectively by a processing circuit.

[0087] 12, the position estimation unit 4, the current control units 5, 5A, and the position estimation voltage generation unit 30 in the configurations of the first and second embodiments are replaced with a processor 41 and a storage device 42. The processor 41 may be a calculation means such as a calculation device, a microprocessor, a microcomputer, a CPU (Central Processing Unit), or a DSP (Digital Signal Processor). Examples of the storage device 42 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), and EEPROM (Electrically EPROM), a registered trademark.

[0088] When the processor 41 and the storage device 42 are used, the functions of the position estimation unit 4, the current control units 5, 5A, and the position estimation voltage generation unit 30 are realized by software, firmware, or a combination of these. The software or firmware is written as a program and stored in the storage device 42. The processor 41 reads out and executes the program stored in the storage device 42. It can also be said that these programs cause a computer to execute the procedures and methods of the functions of the position estimation unit 4, the current control units 5, 5A, and the position estimation voltage generation unit 30. For example, the storage device 42 can be a non-volatile or volatile semiconductor memory such as a ROM, an EPROM, or an EEPROM, a flexible disk, an optical disk, a compact disk, a DVD, or the like.

[0089] The functions of the position estimation unit 4, the current control units 5, 5A, and the position estimation voltage generation unit 30 may be partially realized by hardware and partially realized by software or firmware. For example, the function of the position estimation voltage generation unit 30 may be realized by using dedicated hardware, and the functions of the position estimation unit 4 and the current control units 5, 5A may be realized by using the processor 41 and the storage device 42.

[0090] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0091] 1 rotating machine, 1a stator, 1b rotor, 2 current detection unit, 3 voltage application unit, 4 position estimation unit, 5, 5A current control unit, 6u, 6v, 6w current extractor, 7 high frequency current amplitude calculation unit, 8 position calculator, 9u, 9v, 9w multiplier, 10u, 10v, 10w integrator, 11 fundamental wave current extractor, 12 DC power supply, 13d, 13q subtractor, 14d d-axis current controller, 14q q-axis current controller, 15 first coordinate converter, 16 two-phase to three-phase converter, 17 second coordinate converter, 18 three-phase to two-phase converter, 22u, 22v, 22w square root calculator, 23u, 23v, 23w adder, 30 position estimation voltage generation unit, 31 high frequency amplitude calculator, 32 high frequency voltage generator, 40 dedicated processing circuit, 41 Processor, 42 storage device, 50 rotor core, 51 shaft, 52 slits, 53 core fragment, 54 slit group, 55a center rib, 55b side rib, 56 edge, 100, 100A control device.

Claims

1. a current detection unit that detects a rotating machine current flowing through the rotating machine; a position estimator that calculates an estimate of a rotor position, which is position information of a rotor of the rotating machine, based on the rotating machine current; a current control unit that generates a first voltage command, which is a command value of a rotating machine voltage for driving the rotating machine, based on the detection value of the rotating machine current and the estimated value of the rotor position; a position estimation voltage generation unit that generates a position estimation voltage for estimating a rotor position, the high-frequency voltage having a frequency higher than that of the first voltage command, and determines a voltage amplitude of the high-frequency voltage based on a physical quantity that is correlated with magnetic saturation of the rotor; a voltage applicator that applies a driving voltage to the rotating machine based on a second voltage command obtained by superimposing the position estimation voltage on the first voltage command; A control device for a rotating machine comprising:

2. The physical quantity is a torque axis current command to be applied to the current control unit. The rotating machine control device according to claim 1 .

3. The physical quantities are a torque axis current command and an excitation axis current command to be applied to the current control unit. The rotating machine control device according to claim 1 .

4. The position estimation voltage generation unit a high frequency amplitude calculator that calculates a coefficient value for determining a voltage amplitude of the high frequency voltage; The coefficient values ​​are used to generate the voltage for position estimation. The rotating machine control device according to claim 1 .

5. A current detection unit that detects a rotating machine current flowing through a rotating machine; a position estimator that calculates an estimate of a rotor position, which is position information of a rotor of the rotating machine, based on the rotating machine current; a current control unit that generates a first voltage command, which is a command value of a rotating machine voltage for driving the rotating machine, based on the detection value of the rotating machine current and the estimated value of the rotor position; a position estimation voltage generating unit that generates a position estimation voltage for estimating a rotor position based on a physical quantity correlated with magnetic saturation of the rotor, the position estimation voltage generating unit generating a high-frequency voltage having a higher frequency than the first voltage command; a voltage applicator that applies a driving voltage to the rotating machine based on a second voltage command obtained by superimposing the position estimation voltage on the first voltage command; Equipped with The position estimation voltage generation unit calculating a coefficient value for determining a voltage amplitude of the high frequency voltage based on the physical quantity, and generating the position estimation voltage using the coefficient value; The coefficient value is negatively correlated with the physical quantity. A control device for a rotating machine comprising:

6. A current detection unit that detects a rotating machine current flowing through a rotating machine; a position estimator that calculates an estimate of a rotor position, which is position information of a rotor of the rotating machine, based on the rotating machine current; a current control unit that generates a first voltage command, which is a command value of a rotating machine voltage for driving the rotating machine, based on the detection value of the rotating machine current and the estimated value of the rotor position; a position estimation voltage generating unit that generates a position estimation voltage for estimating a rotor position based on a physical quantity correlated with magnetic saturation of the rotor, the position estimation voltage generating unit generating a high-frequency voltage having a higher frequency than the first voltage command; a voltage applicator that applies a driving voltage to the rotating machine based on a second voltage command obtained by superimposing the position estimation voltage on the first voltage command; Equipped with The position estimation voltage generation unit calculating a coefficient value for determining a voltage amplitude of the high frequency voltage based on the physical quantity, and generating the position estimation voltage using the coefficient value; When the desired detection accuracy is not obtained for the estimated value of the rotor position, the coefficient value is controlled to be increased. A control device for a rotating machine comprising:

7. the current control unit includes a fundamental wave component extractor that removes harmonic superimposition components included in the detection value of the rotating machine current and extracts a fundamental wave component, generating the first voltage command based on an output of the fundamental wave component extractor and the estimated value of the rotor position; The control device for a rotating machine according to any one of claims 1 to 6.

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