control device

Abstract

To increase the accuracy of torque control on a dynamo-electric motor 6.SOLUTION: A control apparatus 10 comprises: a pickup control unit 2 that outputs a pickup voltage command to feed a DC current to a dynamo-electric motor 6 on the basis of a current vector flowing in the dynamo-electric motor 6; a magnetic flux calculator 22 that outputs a calculated magnetic flux vector on the basis of a current vector, the pickup voltage command, and a primary resistance nominal value of the dynamo-electric motor 6; a calculated magnetic flux extraction device 24 that extracts calculated magnetic flux vectors at three time points at a constant interval from calculated magnetic flux vectors until a time of identification; a magnetic flux correction calculation device 30 that outputs a magnetic flux correction value, a relative magnetic flux vector, and the time interval between the three time points on the basis of the calculated magnetic flux vectors at the three time points; an adjustment device 31 that outputs a magnetic flux correction adjustment value on the basis of the magnetic flux correction value and the relative magnetic flux vector; and a primary resistance calculator 32 that calculates a primary resistance of the dynamo-electric motor 6 on the basis of the current vector, the primary resistance nominal value, the time interval, and the magnetic flux correction adjustment value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device that performs torque control for an electric motor. [Background Art]

[0002] From the viewpoints of improving the maintainability of electric motors and achieving miniaturization and higher output of electric motors, control devices for electric motors that are not provided with a speed sensor (which do not use a speed sensor), so-called speed-sensorless electric motor control devices, are known (see, for example, Patent Document 1). When controlling the torque of an electric motor with such a control device, it is generally necessary to estimate the speed (angular velocity) of the electric motor.

[0003] FIG. 3 is a diagram showing a configuration example of a conventional control device 100A, which is a so-called speed-sensorless electric motor control device that does not use a speed sensor.

[0004] As shown in FIG. 3, the control device 100A includes a torque control unit 1, a pull-up control unit 2, a switching unit 3, a power conversion unit 4, a current detection unit 5, an initial value estimation unit 7, an identification timer 21, a magnetic flux calculator 22, a calculated magnetic flux memory 23, a calculated magnetic flux extractor 24, a magnetic flux correction calculator 25, and a primary resistance calculator 26. First, the operations of the torque control unit 1, the pull-up control unit 2, the switching unit 3, the power conversion unit 4, the current detection unit 5, and the initial value estimation unit 7 will be described. The operations of the identification timer 21, the magnetic flux calculator 22, the calculated magnetic flux memory 23, the calculated magnetic flux extractor 24, the magnetic flux correction calculator 25, and the primary resistance calculator 26 will be described later.

[0005] The current detection unit 5 detects a current vector i flowing through the electric motor 6, and outputs the detected current vector i to the torque control unit 1, the pull-up control unit 2, the initial value estimation unit 7, the magnetic flux calculator 22, and the primary resistance calculator 26.

[0006] The pickup control unit 2 receives a current vector i, a DC current command I, and a current phase angle command θ as inputs. Based on the current vector i, the DC current command I, and the current phase angle command θ, the pickup control unit 2 generates a pickup voltage command v0 to supply the DC current instructed by the DC current command I and the current phase angle command θ to the motor 6, and outputs it to the switching unit 3, the initial value estimation unit 7, and the magnetic flux calculator 22.

[0007] The initial value estimation unit 7 receives the current vector i, the pickup voltage command v0, the primary resistance R1 of the motor 6, and the pickup control start command ST as inputs. Based on the current vector i, the pickup voltage command v0, and the primary resistance R1 of the motor 6, the initial value estimation unit 7 calculates the initial speed ωm0 and the initial secondary magnetic flux φ20 of the motor 6 and outputs them to the torque control unit 1.

[0008] The torque control unit 1 receives a torque control start command SW, a current vector i, an initial velocity ωm0, and an initial secondary magnetic flux φ20 as inputs. When the torque control start command SW is turned on, the torque control unit 1 uses the initial velocity ωm0 and the initial secondary magnetic flux φ20 as initial values ​​and generates a torque control voltage command V1 based on the current vector i to control the torque of the motor 6, and outputs it to the switching unit 3. Note that when the power to the motor 6 is turned on, the torque control start command SW is in the off state.

[0009] The switching unit 3 receives the torque control start command SW, the pickup voltage command v0, and the torque control voltage command V1 as inputs. Until the torque control start command SW is turned on, the switching unit 3 outputs the pickup voltage command v0 as a voltage command V* to the power conversion unit 4. When the torque control start command SW is turned on, the switching unit 3 outputs the torque control voltage command V1 as a voltage command V* to the power conversion unit 4.

[0010] The power conversion unit 4 amplifies the voltage command V* and supplies power to the motor 6.

[0011] With the configuration described above, the initial speed ωm0 and initial secondary magnetic flux φ20 of the motor 6 are estimated by the pickup control unit 2 and the initial value estimation unit 7 until the torque control start command SW is turned on. When the torque control start command SW is turned on, the torque control of the motor 6 is performed using the initial speed ωm0 and initial secondary magnetic flux φ20 at the time the torque control start command SW was turned on as initial values. The timing of turning on the torque control start command SW is determined based on the pickup control execution time, the state of the initial speed ωm0 and initial secondary magnetic flux φ20, etc.

[0012] As described above, the initial value estimation unit 7 estimates the initial speed ωm0 and initial secondary magnetic flux φ20 of the motor 6 based on the current vector i and the picked-up voltage command v0. Figure 4 shows an example of the configuration of the initial value estimation unit 7.

[0013] As shown in Figure 4, the initial value estimation unit 7 includes a real magnetic flux estimation unit 9, a real magnetic flux memory 10, a real magnetic flux extraction unit 11, an initial velocity estimation unit 12, an initial magnetic flux estimation unit 13, and a calculation timer 14.

[0014] The actual magnetic flux estimation unit 9 receives the current vector i, the pickup voltage command v0, and the primary resistance R1 of the motor 6 as input. Based on the current vector i, the pickup voltage command v0, and the primary resistance R1 of the motor 6, the actual magnetic flux estimation unit 9 calculates the actual magnetic flux estimation vector φ2r of the motor 6 from equation (A) and outputs it to the actual magnetic flux memory 10.

[0015]

number

[0016] Here, L1 is the primary self-inductance of the motor 6, L2 is the secondary self-inductance of the motor 6, and M is the mutual inductance of the motor 6.

[0017] The calculation timer 14 receives the pickup control start command ST. The calculation timer 14 is a timer counter that is reset to zero at the edge of the pickup control start command ST, and outputs the pickup time t0 to the actual magnetic flux memory 10, the actual magnetic flux extraction unit 11, the initial velocity estimation unit 12, and the initial magnetic flux estimation unit 13.

[0018] The actual magnetic flux memory 10 receives the actual magnetic flux estimation vector φ2r and the pickup time t0 as input. The actual magnetic flux memory 10 stores the actual magnetic flux estimation vector φ2r, which changes moment by moment, in the interval from time 0 to pickup time t0.

[0019] The actual magnetic flux extraction unit 11 extracts the actual magnetic flux estimation vectors φ(t00), φ(t01), and φ(t02) for three arbitrary time points t00, t01, and t02 in the interval from time t0 to pickup time t0 from the actual magnetic flux memory 10, and outputs them to the initial velocity estimation unit 12.

[0020] The initial velocity estimation unit 12 receives the pickup time t0 and the estimated real magnetic flux vectors φ(t00), φ(t01), and φ(t02) at time points t00, t01, and t02, and calculates the initial velocity ωm0. Specifically, the initial velocity estimation unit 12 first determines the center R of the circle passing through the endpoints of each of the three estimated real magnetic flux vectors φ(t00), φ(t01), and φ(t02) using equations (B) to (E).

[0021]

number

[0022] Here, vector F1 is the vector indicating the endpoint of the estimated real magnetic flux vector φ(t01) as seen from the endpoint of the estimated real magnetic flux vector φ(t00). Vector F2 is the vector indicating the endpoint of the estimated real magnetic flux vector φ(t02) as seen from the endpoint of the estimated real magnetic flux vector φ(t00). Also, (F1A,F1B), (F2A,F2B), and (RA,RB) are the components of vectors F1, F2, and R, respectively.

[0023] Next, the initial speed estimating unit 12 obtains, from equation (F), the angle θC between the actual magnetic flux estimated vector φ(t00) and the actual magnetic flux estimated vector φ(t02) as viewed from the center R of the circle.

[0024]

Mathematical expression

[0025] In the formula (F), "×" represents a vector cross product, and "·" represents a vector dot product.

[0026] The rotational speed of the electric motor 6 from time t00 to time t02 (for example, several tens of milliseconds) can be considered to be substantially constant. Therefore, the initial speed estimating unit 12 can estimate the initial speed ωm0 from equation (G).

[0027]

Mathematical expression

[0028] The initial speed estimating unit 12 outputs the estimated initial speed ωm0 to the torque control unit 1 (not shown in FIG. 2) and the initial magnetic flux estimating unit 13.

[0029] The initial magnetic flux estimating unit 13 receives a pick-up time t0, the initial speed ωm0, and a current vector i as inputs. The initial magnetic flux estimating unit 13 obtains an initial secondary magnetic flux φ20 from equation (H).

[0030]

Mathematical expression

[0031] In the formula (H), "j" is an imaginary unit. T2 is a secondary time constant of the electric motor 6, and is calculated from L2 / R2 using the secondary resistance R2 of the electric motor 6. φxx is residual magnetic flux at the start of pick-up control. Note that the second term of equation (H) can also be obtained as a relative vector of the actual magnetic flux estimated vector φ2r with respect to the vector R.

[0032] The above configuration has room for improvement, as shown below.

[0033] If an error occurs in the primary resistance R1 due to temperature fluctuations of the electric motor 6, the integral term in equation (A) will cause this error to be accumulated in the actual magnetic flux estimation vector φ2r, which is the output value of the actual magnetic flux estimator 9. As a result, errors occur in the actual magnetic flux estimation vectors φ(t00), φ(t01), and φ(t02), which are the outputs of the actual magnetic flux extractor 11. When errors occur in the actual magnetic flux estimation vectors φ(t00), φ(t01), and φ(t02), similar errors also occur in the initial velocity ωm0 and initial secondary magnetic flux φ20, which are estimated by equations (B) to (H) based on the actual magnetic flux estimation vectors φ(t00), φ(t01), and φ(t02).

[0034] When an error occurs in the primary resistance R1 of the electric motor 6, errors occur in the initial speed ωm0 and initial secondary magnetic flux φ20 estimated by the initial value estimation unit 7. As a result, errors exist in the initial values ​​input to the torque control unit 1, and the accuracy of torque control of the electric motor 6 is not always sufficient.

[0035] Therefore, in the conventional control device 100A, the primary resistance R1 in equation (A) is calculated using a magnetic flux calculator 22, a calculated magnetic flux memory 23, a calculated magnetic flux extractor 24, a magnetic flux correction calculator 25, and a primary resistance calculator 26. The operation of each part will be explained below with reference to Figure 3.

[0036] The identification timer 21 is a timer counter that is reset to zero at the edge of the pickup control start command ST, and outputs the identification time tx to the calculation flux memory 23 and the calculation flux extractor 24.

[0037] The magnetic flux calculator 22 receives the current vector i, the pickup voltage command v0, and the primary resistance nominal value R1C as input. Based on the pickup voltage command v0 and the primary resistance nominal value R1C, the magnetic flux calculator 22 calculates the calculated magnetic flux vector φ2s using equation (I).

[0038]

number

[0039] The magnetic flux calculator 22 outputs the calculated magnetic flux vector φ2s to the calculated magnetic flux memory 23.

[0040] The calculation flux memory 23 stores the calculation flux vector φ2s, which changes moment by moment, in the interval from time 0 to the identified time tx.

[0041] The calculation flux extraction unit 24 extracts the calculation flux vectors φs(tx0), φs(tx1), and φs(tx2), which are the calculation flux vectors φs at three equally spaced time points tx0, tx1, and tx2 in the interval from time 0 to identified time tx, from the calculation flux memory 23 and outputs them to the flux correction calculator 25. If the time interval for extracting the calculation flux vectors φs(tx0), φs(tx1), and φs(tx2) is txs, then the following equation (J) holds. txs = tx1 - tx0 = tx2 - tx1 Equation (J)

[0042] The magnetic flux correction calculator 25 receives the calculated magnetic flux vectors φs(tx0), φs(tx1), and φs(tx2) as input. The magnetic flux correction calculator 25 outputs the magnetic flux correction value φsD and the time interval txs to the primary resistance calculator 26. The operation of the magnetic flux correction calculator 25 will be explained in more detail below.

[0043] As shown in equation (K), assume that the nominal value of the primary resistance R1C is deviated from the true value of the primary resistance R1 by an error ΔR. R1=R1C+ΔR Formula (K)

[0044] Substituting equation (K) for the nominal value of the primary resistance R1C in equation (I), and assuming that the current vector i is constant, equation (I) can be expressed as equation (L) using equation (A). Equation (L): φ2s = φ2r + ΔR·i·t

[0045] In equation (L), t is the calculation time for the calculated magnetic flux vector φ2s. Also, L2 ≈ M.

[0046] Next, we calculate the relative magnetic fluxes FS1 and FS2 from equations (M) and (N). FS1 = φr(tx1) - φr(tx0) =φs(tx1)-φs(tx0)-txs*ΔR*i Formula (M) FS2 = φr(tx2) - φr(tx0) =φs(tx2)-φs(tx0)-2*txs*ΔR*i Formula (N)

[0047] Here, the magnetic flux correction value φsD is given by equation (M1). φsD = 2 * txs * ΔR * i Equation (M1)

[0048] Using equation (M1), equations (M) and (N) become equations (M2) and (N2), respectively. FS1 = φr(tx1) - φr(tx0) =φs(tx1)-φs(tx0)-φsD / 2 Formula (M2) FS2 = φr(tx2) - φr(tx0) =φs(tx2)-φs(tx0)-φsD Formula (N2)

[0049] Using equations (M2) and (N2), we calculate E0 from equation (0). E0=(FS1-FS2)·(FS1-FS2)-FS1·FS1 =E0A+E0B*φsD Equation (0)

[0050] Note that φr(tx0), φr(tx1), and φr(tx2) are the actual magnetic flux vectors φ2r at times tx0, tx1, and tx2. Also, E0A and E0B are the coefficients obtained by summarizing E0 with respect to the magnetic flux correction value φsD.

[0051] Here, in equation (H), if the pickup time t0 is made sufficiently small with respect to the second-order time constant T2, the actual magnetic flux vector φ2r can be considered to trace a circle, so the vectors φr(tx0), φr(tx1), and φr(tx2) lie on the same circle. Furthermore, the vectors φr(tx0), φr(tx1), and φr(tx2) are extracted at equal intervals (txs intervals). Therefore, the phase difference between vector φr(tx0) and vector φr(tx1) is equal to the phase difference between vector φr(tx1) and vector φr(tx2), so the value of E0 is always 0. The magnetic flux correction value φsD can be obtained by substituting E0=0 into equation (O) and rearranging, resulting in the following equation (P). φsD = -E0A / E0B Equation (P)

[0052] The magnetic flux correction calculator 25 outputs the magnetic flux correction value φsD and the time interval txs obtained by equation (J) to the primary resistance calculator 26.

[0053] The primary resistance calculator 26 receives the magnetic flux correction value φsD, the time interval txs, the current vector i, and the primary resistance nominal value R1C as inputs. Based on the magnetic flux correction value φsD, the time interval txs, the current vector i, and the primary resistance nominal value R1C, the primary resistance calculator 26 calculates the primary resistance R1 using the above-described equations (M1) and (K). [Prior art documents] [Patent Documents]

[0054] [Patent Document 1] Japanese Patent Publication No. 2001-211689 [Patent Document 2] Japanese Patent Publication No. 2001-211697 [Overview of the initiative] [Problems that the invention aims to solve]

[0055] In the conventional control device 100A, the magnetic flux correction value φsD is calculated using equation (P), and the error ΔR of the primary resistance R1 is calculated from the magnetic flux correction value φsD. Here, in the process of calculating the error ΔR, it was assumed that the actual magnetic flux vector φ2r traces a circle. However, in reality, according to equation (H), the radius of rotation of the actual magnetic flux vector φ2r is attenuated by the second-order time constant T2. Therefore, the magnetic flux correction value φsD obtained by equation (P) is subject to error due to the attenuation of the radius of rotation. As a result, an error remains in the calculated primary resistance R1, and errors also occur in the initial velocity ωm0 and initial secondary magnetic flux φ20 estimated by the initial value estimation unit 7.

[0056] If errors occur in the initial velocity ωm0 and the initial secondary magnetic flux φ20, the initial values ​​of the control by the torque control unit 1 will contain errors, and therefore, it may not always be possible to control the torque of the electric motor 6 with high precision.

[0057] In view of the above-mentioned problems, the object of the present invention is to provide a control device that can improve the accuracy of torque control of an electric motor. [Means for solving the problem]

[0058] To solve the above problems, the control device according to the present invention is a control device for an electric motor, comprising: a current detector that detects a current vector flowing through the electric motor; a pickup control unit that outputs a pickup voltage command to supply a DC current to the electric motor based on the current vector; a magnetic flux calculator that outputs a calculated magnetic flux vector based on the current vector, the pickup voltage command, and the nominal primary resistance value of the electric motor; a calculated magnetic flux extractor that extracts calculated magnetic flux vectors at three equally spaced time points from the calculated magnetic flux vector up to an identified time; a magnetic flux correction calculator that outputs a magnetic flux correction value, a relative magnetic flux vector, and the time intervals between the three time points based on the calculated magnetic flux vectors at the three time points; a regulator that outputs a magnetic flux correction adjustment value based on the magnetic flux correction value and the relative magnetic flux vector; and a primary resistance calculator that calculates the primary resistance of the electric motor based on the current vector, the nominal primary resistance value, the time intervals, and the magnetic flux correction adjustment value. [Effects of the Invention]

[0059] The control device according to the present invention can improve the accuracy of torque control of an electric motor. [Brief explanation of the drawing]

[0060] [Figure 1] This figure shows an example configuration of a control device according to one embodiment of the present invention. [Figure 2] Figure 1 is a diagram illustrating the operation of the regulator shown. [Figure 3] This figure shows an example of a conventional control device configuration. [Figure 4] Figures 1 and 3 show examples of the configuration of the initial value estimation unit. [Modes for carrying out the invention]

[0061] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0062] Figure 1 is a diagram showing an example configuration of a control device 10 according to one embodiment of the present invention. The control device 10 according to this embodiment is a so-called speed sensorless motor control device that controls the torque of the motor 6 without using a speed sensor. In Figure 1, the same reference numerals are used for components similar to those in Figure 3, and their descriptions are omitted.

[0063] The control device 100 shown in Figure 1 comprises a torque control unit 1, a pickup control unit 2, a switching unit 3, a power conversion unit 4, a current detection unit 5, an initial value estimation unit 7, an identification timer 21, a magnetic flux calculator 22, a calculated magnetic flux memory 23, a calculated magnetic flux extractor 24, a magnetic flux correction calculator 30, a regulator 31, and a primary resistance calculator 32. The control device 100 shown in Figure 1 differs from the control device 100A shown in Figure 3 in that the magnetic flux correction calculator 25 is replaced with a magnetic flux correction calculator 30, a regulator 31 is added, and the primary resistance calculator 26 is replaced with a primary resistance calculator 32.

[0064] The magnetic flux correction calculator 30 receives the calculated magnetic flux vectors φs(tx0), φs(tx1), and φs(tx2) as input. The magnetic flux correction calculator 30 calculates the magnetic flux correction value φs and the time interval txs in the same manner as the magnetic flux correction calculator 25. The magnetic flux correction calculator 30 also calculates the relative magnetic flux vectors φss1 and φss2 based on the calculated magnetic flux vectors φs(tx0), φs(tx1), and φs(tx2) using equations (Q) and (R). The relative magnetic flux vector φss1 is a vector that indicates the endpoint of the calculated magnetic flux vector φs(tx1) as seen from the endpoint of the calculated magnetic flux vector φs(tx0). The relative magnetic flux vector φss2 is a vector that indicates the endpoint of the calculated magnetic flux vector φs(tx2) as seen from the endpoint of the calculated magnetic flux vector φs(tx0). φss1=φs(tx1)-φs(tx0) Formula (Q) φss2=φs(tx2)-φs(tx0) Formula (R)

[0065] The magnetic flux correction calculator 30 outputs the magnetic flux correction value φsD and the relative magnetic flux vectors φss1 and φss2 to the regulator 31, and outputs the time interval txs to the primary resistance calculator 32.

[0066] The regulator 31 receives the magnetic flux correction value φs and the relative magnetic flux vectors φss1 and φss2 as input. Based on the magnetic flux correction value φs and the relative magnetic flux vectors φss1 and φss2, the regulator 31 calculates the magnetic flux correction adjustment value φsE using equations (S) to (X). Specifically, the regulator 31 first calculates the primary resistance error correction relative magnetic flux vectors FSM and FSE using equations (S) and (T). FSM=φss1-φsD / 2 Formula (S) FSE = φss² - φsD Equation (T)

[0067] Let FR be the center of the circle passing through the three points (0,0), FSM, and FSE, and let φsG be the adjustment value. The regulator 31 calculates E0_T from the following equations (U) to (V1). FSM_T=e -txs / T2 *(FSM-FR)+FR Formula (U) FSE_T=e -2*txs / T2 *(FSE-FR)+FR Formula (V) FSM_T2=FSM_T-φsG / 2 Formula (U1) FSE_T2=FSE_T-φsG Formula (V1) E0_T=(FSE_T-FSM_T)·(FSE_T-FSM_T) -FSM_T·FSM_T =E0A_T+E0B_T*φsG Equation (W)

[0068] The adjustment value φsG is calculated by setting E0_T=0, and the regulator 31 calculates the magnetic flux correction adjustment value φsE using the following equation (X). Equation (X): φsE = φsD - φsG

[0069] Below, equations (S) to (X) will be explained with reference to Figure 2.

[0070] In Figure 2, the circle indicated by the dashed line is a circle centered at point R (the convergence point of the actual secondary magnetic flux). Also in Figure 2, φs() represents the calculated secondary magnetic flux including the error due to the primary resistance R1. φr() represents the actual secondary magnetic flux and is the point where the radius of the circle centered at R, indicated by the dashed line, has decayed with a time constant T2.

[0071] Based on the calculated secondary magnetic flux φs, the magnetic flux correction value φsD obtained by the magnetic flux correction calculator 30 from equations (K) to (P) can be expressed by the following equation (Y). φsD = 2 * txs * ΔR * i + φsT Equation (Y)

[0072] Here, φsT is the error component that takes into account that "the radius of rotation of the estimated actual magnetic flux vector φ2r is decaying with a second-order time constant T2".

[0073] Furthermore, from equations (S) and (T), a circle is obtained in which the primary resistance error ΔR is not included and the radius is approximately the same as that of the actual magnetic flux (in Figure 2, the circle is shown by the dashed line). This circle is centered at point FR and passes through three points: the coordinate reference point (φs(tx0)), FSM, and FSE. Also, from equations (U) and (V), FSM_T and FSE_T are obtained in which motion equivalent to that of the actual secondary magnetic flux φr() is realized. FSM_T and FSE_T are points in which the radius of the circle centered at point FR, shown by the dashed line, has decayed by the secondary time constant T2.

[0074] Since equations (U1) to (W) are similar to equations (M2) to (O) which calculate the magnetic flux correction value φsD, the adjustment value φsG can be obtained from equations (U1) to (W). The adjustment value φsG obtained from equations (U1) to (W) can be considered as the error φsT due to the fact that "the radius of rotation of the estimated actual magnetic flux vector φ2r is attenuated by the second-order time constant T2". From this, equation (Z) is obtained. φsE=φsD-φsG≒φsD-φsT=2*txs*ΔR*i Formula (Z)

[0075] Referring again to Figure 1, the regulator 31 outputs the magnetic flux correction adjustment value φsE calculated by equation (Z) to the primary resistance calculator 32.

[0076] The primary resistance calculator 32 receives the current vector i, the nominal primary resistance value R1C, the time interval txs, and the magnetic flux correction adjustment value φsE as inputs. Based on the nominal primary resistance value R1C, the time interval txs, and the magnetic flux correction adjustment value φsE, the primary resistance calculator 32 calculates the primary resistance R1 using equations (Z) and (K) and outputs it to the initial value estimation unit 7.

[0077] As described above, according to this embodiment, the control device 100 includes a magnetic flux correction calculator 30, a regulator 31, and a primary resistance calculator 32. The magnetic flux correction calculator 30 outputs a magnetic flux correction value φsD, relative magnetic flux vectors φss1, φss2, and time interval txs based on the calculated magnetic flux vectors φs(tx0), φs(tx1), and φs(tx2) at three equally spaced time points (tx0, tx1, tx2). The regulator 31 outputs a magnetic flux correction adjustment value φsE based on the time correction value φsD and relative magnetic flux vectors φss1, φss2. The primary resistance calculator 32 calculates the primary resistance R1 of the motor 6 based on the current vector i, the primary resistance nominal value R1C, the time interval txs, and the magnetic flux correction adjustment value φsE.

[0078] As explained with reference to equations (S) to (X), by adjusting the magnetic flux correction value φsD based on the relative magnetic flux vectors φss1 and φss2, it is possible to obtain a magnetic flux correction adjustment value φsE that takes into account the fact that the rotation radius of the estimated actual magnetic flux vector φ2r is attenuated by a time constant T2. Then, by calculating the primary resistance R1 using the magnetic flux correction adjustment value φsE, it is possible to calculate the primary resistance R1 that takes into account the effect of the attenuation of the rotation radius. As a result, the accuracy of torque control of the electric motor 6 can be improved.

[0079] Although the embodiments described above are representative examples, it will be apparent to those skilled in the art that many modifications and substitutions are possible within the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited by the embodiments described above, and various modifications and changes are possible without departing from the scope of the claims. [Explanation of symbols]

[0080] 100, 100A control device 1 Torque Control Unit 2. Pickup control unit 3. Switching section 4 Power Conversion Unit 5 Current detector 6 Electric motor 7. Initial Value Estimation Unit 9. Actual magnetic flux estimation unit 10. Real magnetic flux memory 11. Actual magnetic flux extraction unit 12 Initial speed estimator 13. Initial magnetic flux estimation unit 21 Identification Timer 22 Magnetic flux calculator 23. Computational Magnetic Flux Memory 24. Computational magnetic flux extractor 25,30 Magnetic flux correction calculator 26,32 Primary resistance calculator 31 Regulator

Claims

[Claim 1] A control device for an electric motor, A current detector for detecting the current vector flowing through the electric motor, A pickup control unit that outputs a pickup voltage command to supply a DC current to the motor based on the current vector, A magnetic flux calculator that outputs a calculated magnetic flux vector based on the current vector, the picked-up voltage command, and the nominal value of the primary resistance of the motor, A calculated magnetic flux extractor extracts calculated magnetic flux vectors at three equally spaced time points from the calculated magnetic flux vector up to the specified time, A magnetic flux correction calculator that outputs a magnetic flux correction value, a relative magnetic flux vector, and the time interval between the three points in time based on the calculated magnetic flux vectors at the three points in time, A regulator that outputs a magnetic flux correction adjustment value based on the magnetic flux correction value and the relative magnetic flux vector, A control device comprising: a primary resistance calculator that calculates the primary resistance of the electric motor based on the current vector, the primary resistance nominal value, the time interval, and the magnetic flux correction adjustment value.

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