Motor control device and motor control method

Abstract

This motor control device that estimates a rotation position of a motor comprises: a parameter identification unit that identifies a motor parameter related to the motor; and a position estimation unit that estimates the rotation position of the motor on the basis of the identified motor parameter. The motor parameter includes, as a calculation parameter for calculating a parameter value, a forgetting coefficient that is a calculation parameter related to the responsiveness of parameter identification. The parameter identification unit performs parameter identification at the response speed of the parameter identification obtained from a time constant calculated on the basis of the forgetting coefficient and a control cycle related to control processing of the parameter identification, and outputs the identified motor parameter toward the position estimation unit.

Description

Motor control device and motor control method

[0001] The present disclosure relates to a motor control device and a motor control method.

[0002] Conventionally, motor control devices having a parameter identifier are known (see, for example, Patent Document 1). In the motor control device, the parameter identifier identifies the motor constants of the motor. The parameter identifier outputs the identified motor constants to, for example, a rotational angle estimator that estimates the rotational position of the motor. The rotational angle estimator then estimates the rotational position of the motor using the motor constants.

[0003] JP 2019-75868 A

[0004] The parameter identifier performs identification of motor constants such as the q-axis inductance (hereinafter referred to as parameter identification) at a predetermined response speed. The response speed of the parameter identification varies depending on the value of the forgetting factor λ used as a weighting factor. Here, the forgetting factor λ is a dimensionless quantity and is not quantified, so it can be any value. If the forgetting factor λ is any value, the response of the parameter identification may not be appropriate.

[0005] For example, when the motor load changes suddenly, the q-axis inductance, which is the actual value, fluctuates due to magnetic saturation. Meanwhile, because the q-axis inductance (estimated value) identified by the parameter identifier uses an arbitrary, unquantified forgetting factor λ, a delay in the parameter identification response can cause the estimated q-axis inductance to lag behind the actual q-axis inductance. When the actual value and the estimated value diverge, that is, when the difference between the actual and estimated values ​​increases, a motor position estimation error occurs in the delayed direction, the current value used to control the motor increases, further advancing magnetic saturation and further increasing the difference between the actual and estimated values. Repeating this process increases the likelihood of the motor losing synchronization.

[0006] Furthermore, for example, if the response of parameter identification is the same as the response of motor current control, it may not be possible to detect changes in inductance, and in this case, the difference between the actual value and the estimated value may become large, which may cause the motor to lose synchronization.As such, since the forgetting factor λ is not quantified, the response speed of parameter identification may cause the motor to lose synchronization.

[0007] Therefore, an object of the present disclosure is to provide a motor control device and a motor control method that can accurately estimate the rotational position of a motor and suppress motor step-out by making the response of parameter identification appropriately fast.

[0008] A motor control device according to the present disclosure is a motor control device that estimates the rotational position of a motor, and includes a parameter identification unit that identifies motor parameters related to the motor, and a position estimation unit that estimates the rotational position of the motor based on the identified motor parameters, wherein the motor parameters include a forgetting factor that is a calculation parameter related to the responsiveness of parameter identification as a calculation parameter for calculating parameter values, and the parameter identification unit performs parameter identification at a response speed of parameter identification calculated from a time constant calculated based on the forgetting factor and a control period related to the control processing of parameter identification, and outputs the identified motor parameters to the position estimation unit.

[0009] The motor control method disclosed herein is a motor control method executed by a motor control device that estimates the rotational position of a motor, in which motor parameters related to the motor are identified and the rotational position of the motor is estimated based on the identified motor parameters, the motor parameters include a forgetting factor, which is a calculation parameter related to the responsiveness of parameter identification, as a calculation parameter for calculating parameter values, and parameter identification is performed at a response speed of parameter identification calculated based on the forgetting factor and a control period related to the control process of parameter identification.

[0010] According to the present disclosure, by setting the response of parameter identification to an appropriate speed, it is possible to accurately estimate the rotational position of the motor and suppress loss of synchronization of the motor.

[0011] FIG. 1 is a diagram relating to a motor control device according to this embodiment. FIG. 2 is a flowchart relating to a motor control method according to this embodiment. FIG. 3 is a diagram relating to the response speed of parameter identification. FIG. 4 is a graph of an example showing changes in various motor parameters. FIG. 5 is a graph of an example showing changes in various motor parameters. FIG. 6 is a graph of an example showing changes in various motor parameters.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, this disclosure is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the components described below can be combined as appropriate, and when there are multiple embodiments, the respective embodiments can also be combined.

[0013] [Present Embodiment] A motor control device 10 according to this embodiment is a device that controls the rotation of a motor 5, and is, for example, a vector control device. The motor 5 is, for example, a three-phase motor, and the motor control device 10 controls the motor 5 by converting a two-phase voltage of the d-axis and q-axis into a three-phase voltage of U-phase, V-phase, and W-phase. The motor control device 10 will be described with reference to FIG. 1 .

[0014] (Motor Control Device) Fig. 1 is a diagram showing a motor control device according to this embodiment. As shown in Fig. 1, the motor control device 10 includes a rotational speed control unit 21, a torque control unit (MTPA: Maximum Torque Per Ampere) 22, a high-frequency signal generator 23, a current control unit 24, two-phase / three-phase conversion units 25, 26, and 30, a PWM control unit 27, a parameter identification unit 28, and a position estimator 29.

[0015] The rotation speed control unit 21 controls the rotation speed of the motor 5, and outputs a speed command value ω ＊ and the estimated rotational speed ω of the motor 5.＾ (In addition," ＾ " is a symbol attached above the letters in the figure) and the estimated speed value ω of the rotation speed of the motor 5 are input. ＾ is input from the position estimation unit 29, which will be described later. The rotational speed control unit 21 calculates the input estimated speed value ω ＾ is the speed command value ω ＊ The torque command value T of the rotational torque of the motor 5 is set to ＊ Output.

[0016] The torque control unit 22 controls the rotation torque of the motor 5, and receives a torque command value T ＊ The torque control unit 22 receives the input torque command value T ＊ Based on this, the current command value Iγδ to be applied to the motor 5 is ＊ Output.

[0017] The high-frequency signal generator 23 applies a high-frequency voltage that becomes a high-frequency signal to the current control unit 24. The high-frequency signal is a voltage that is applied to estimate the rotational position of the motor 5.

[0018] The current control unit 24 controls the current input to the motor 5, and receives a current command value Iγδ from the torque control unit 22. ＊ is input. ＊ are the current command values ​​for the d-axis and q-axis, respectively. ＊ Based on this, the current and voltage (Vγδ) input to the two-phase / three-phase conversion unit 25 ＊ ) is controlled. The current control unit 24 also performs non-interference control to suppress current oscillation due to interference between the d- and q-axes based on the current (Iγδ) output from the two-phase / three-phase conversion unit 26, which will be described later. Furthermore, the current control unit 24 controls the output voltage (Vγδ ＊ ) is input to the parameter identification unit 28.

[0019] The two-phase / three-phase converter 25 converts the current and voltage (Vγδ) in the dq orthogonal two-axis rotating coordinate system input from the current controller 24. ＊ ) into the current and voltage (Vuvw) in the UVW three-phase stationary coordinate system ＊The two-phase / three-phase converter 25 converts the converted voltage (Vuvw ＊ ) is output to the PWM control unit 27.

[0020] The two-phase / three-phase converter 26 converts the current (iuvw) and voltage in the UVW three-phase stationary coordinate system output from the two-phase / three-phase converter 25 into a current (Iγδ) and voltage in a dq orthogonal two-axis rotating coordinate system. The two-phase / three-phase converter 26 inputs the converted current (Iγδ) to the current control unit 24 and the parameter identification unit 28. The two-phase / three-phase converters 25 and 26 also input the rotational position θ of the motor 5 estimated by a position estimation unit 29 (described later). ＾ is input, and the rotation position θ ＾ The conversion process is performed based on the

[0021] The two-phase / three-phase conversion unit 30 converts the current (iuvw) and voltage in the UVW three-phase stationary coordinate system output from the two-phase / three-phase conversion unit 25 into a current (Iαβ) and voltage in a dq orthogonal two-axis rotating coordinate system, similar to the two-phase / three-phase conversion unit 26. The two-phase / three-phase conversion unit 30 inputs the converted current (Iαβ) to the position estimation unit 29.

[0022] The PWM control unit 27 converts the voltage (Vuvw ＊ ) and outputs a PWM signal to the motor 5.

[0023] The parameter identifying unit 28 identifies motor parameters related to the motor 5. The motor parameters include the q-axis inductance Lq and the d-axis inductance Ld of the motor 5. The parameter identifying unit 28 identifies the voltage (Vγδ) input from the current control unit 24. ＊ ) and the current (Iγδ) input from the two-phase / three-phase conversion unit 26, and the obtained voltage (Vγδ ＊ The motor parameters are identified based on the current (Iγδ) and the torque (Iγδ). The motor parameters are calculated using a predetermined calculation formula. The predetermined calculation formula includes calculation parameters for calculating the parameter values ​​of the motor parameters. The calculation parameters include a forgetting factor λ, which is a calculation parameter related to the response of the parameter identification.

[0024] The predetermined calculation formula will now be described. The coordinate systems used in the following formulas include a three-phase AC coordinate system of uvw axes, a fixed coordinate system of αβ axes, a rotating coordinate system of dq axes, and an estimated rotating coordinate system of γδ axes.

[0025] When the motor 5 is an interior permanent magnet synchronous motor (IPMSM), the state equation of the estimated rotating coordinate system is expressed by equation (1), and parameter identification is performed based on this equation (1).

[0026]

[0027] When equation (1) is discretized with respect to the sampling period (time) T, equation (2) is obtained.

[0028]

[0029] By rearranging equation (2), equation (3) is obtained.

[0030]

[0031] Equation (3) can be further transformed into equation (4).

[0032]

[0033] In this case, the terms of equation (4) become equations (5) to (7).

[0034]

[0035] Here, Equation (5) is defined as a parameter matrix, which can be identified by using the matrices of Equations (6) and (7) based on the recursive least squares method shown in Equations (8) and (9).

[0036]

[0037] Equation (9) is a parameter identification formula for iterative calculation, and the initial value is Θ ０ , P ０ From then on, whenever input y and z are obtained, Θ Ｎis updated. Furthermore, the forgetting factor λ is included in the equation (9). Furthermore, P[n] in the equation (9) can be expressed as a parameter matrix of the equation (10).

[0038]

[0039] Here, the intermediate variable M １ ~M ３ We introduce the intermediate variable M １ is defined by equation (11), and similarly, the intermediate variable M ２ is defined by equation (12), and the intermediate variable M ３ is defined by equation (13).

[0040]

[0041] The q-axis inductance Lq as a motor parameter obtained from the intermediate variables is given by equation (14).

[0042]

[0043] The parameter identification unit 28 includes a system identification unit 31 and a parameter calculation unit 32. The system identification unit 31 identifies the response speed of parameter identification. ＊ The system identification unit 31 receives the voltage (Vγδ) from the current control unit 24 and the current (Iγδ). ＊ ) to identify the response speed of the current control of the motor 5. The system identification unit 31 also identifies the response speed of the parameter identification based on the forgetting factor λ.

[0044] Here, the forgetting factor λ and the response speed of parameter identification will be explained. The forgetting factor λ is a dimensionless quantity. On the other hand, the unit of the response speed of parameter identification is (rad / s). Therefore, in order to handle the forgetting factor λ in units of the response speed (rad / s), the time constant is calculated using the following equations (15) and (16). The unit of the time constant is time.

[0045] Time constant = τ × Ts (15) τ = 1 / (1 - λ) (16) τ: memory horizon Ts: control period (sampling period T) λ: forgetting factor

[0046] The system identification unit 31 calculates the memory horizon τ based on the forgetting factor λ using equation (16), and calculates the time constant based on the memory horizon τ and the control period Ts using equation (15). The system identification unit 31 converts the reciprocal of the time constant into a response speed (angular velocity) for parameter identification.

[0047] The parameter calculation unit 32 identifies the motor parameters from a predetermined calculation formula at a response speed based on the forgetting factor λ. The parameter calculation unit 32 outputs the identified motor parameters to the position estimation unit 29.

[0048] The position estimation unit 29 estimates the rotational position and rotational speed of the motor 5. The induced voltage estimation observer 35 estimates the current iαβ and voltage Vαβ in the two-phase stationary coordinate system. ＊ The position estimator 29 includes an induced voltage estimation observer 35 and a position estimator 36.

[0049] The induced voltage estimation observer 35 estimates the input current iαβ and voltage Vαβ. ＊ Based on this, the extended induced voltage e excited by the rotating motor 5 ＾ The induced voltage estimation observer 35 estimates the extended induced voltage e ＾ The observer model includes motor parameters such as the q-axis inductance Lq. The induced voltage estimation observer 35 estimates the extended induced voltage e excited by the high-frequency signal applied by the high-frequency signal generator 23. ２ ＾ and the extended induced voltage e excited in proportion to the rotation speed of the motor 5. １ ＾ By superimposing these, the extended induced voltage e ＾ It is estimated that:

[0050] The position estimator 36 receives the extended induced voltage e ＾The position estimator 36 receives the extended induced voltage e ＾ Based on this, the rotational position θ of the motor 5 ＾ The position estimator 36 estimates the estimated rotational position θ of the motor 5. ＾ Based on this, the rotational position θ of the motor 5 ＾ By calculating the differential value of ω, the rotation speed (estimated speed value) of the motor 5 is calculated. ＾ The position estimator 36 estimates the estimated rotation speed ω of the motor 5. ＾ is output to the rotation speed control unit 21.

[0051] (Motor Control Method) Next, a motor control method by motor control device 10 will be described with reference to Figure 2. Figure 2 is a flowchart relating to the motor control method according to this embodiment. In the motor control method shown in Figure 2, two-phase / three-phase conversion units 26, 30 convert the current (iuvw) in the UVW three-phase stationary coordinate system acquired at the output side of PWM control unit 27 into a current (Iγδ) in a dq orthogonal two-axis rotating coordinate system (step S1).

[0052] Next, the parameter identification unit 28 calculates the voltage (Vγδ) from the current control unit 24. ＊ ) and the current (Iγδ) from the two-phase / three-phase converter 26, the parameter identifier 28 identifies motor parameters including the q-axis inductance Lq (step S2). The parameter identifier 28 outputs the identified motor parameters to the induced voltage estimation observer 35 of the position estimator 29.

[0053] The back electromotive force estimating observer 35 corrects the observer model based on the motor parameters acquired from the parameter identifying unit 28 (step S3). Then, the back electromotive force estimating observer 35 uses the corrected observer model to estimate the current iαβ and the voltage Vαβ. ＊ Based on this, the extended induced voltage e ＾ Estimate.

[0054] After this, the position estimator 36 of the position estimator 29 calculates the estimated extension induced voltage e ＾ Based on this, the rotational position θ of the motor 5 ＾ and rotation speed ω ＾(Step S4). The position estimator 36 estimates the estimated rotation speed ω of the motor 5. ＾ is output to the rotation speed control unit 21.

[0055] Then, the rotation speed control unit 21 calculates the input rotation speed ω ＾ is the speed command value ω ＊ The rotational speed control unit 21, the torque control unit 22, and the current control unit 24 perform current control calculations so as to obtain the above (step S5), and the processing relating to the motor control is completed.

[0056] Next, referring to Figures 3 to 6, we will explain how the response speed of parameter identification changes depending on the parameter value of the forgetting factor λ. Figure 3 is a diagram related to the response speed of parameter identification. Figures 4 to 6 are example graphs showing changes in various motor parameters. The forgetting factor λ was evaluated by simulation, simulating an operating situation in which the load on the motor 5 changes sharply.

[0057] 4 to 6, the graphs on the left side show the time changes of the d-axis current and the q-axis current. The upper graph shows the d-axis current, and the lower graph shows the q-axis current. In both the upper and lower graphs, the vertical axis represents the current value (A) and the horizontal axis represents time (s).

[0058] 4 to 6, the central graph shows the magnetic pole position (rotational position) of the motor 5 and the change over time in the position estimation error. The upper graph is a graph of the magnetic pole position of the motor 5, which is an estimated value, and the middle graph is a graph of the magnetic pole position of the motor 5, which is a true value (actual value). The lower graph is a graph of the position estimation error Δθ, which is the difference between the estimated value and the true value. In the upper and middle graphs, the vertical axis represents angle (rad) and the horizontal axis represents time (s). In the lower graph, the vertical axis represents angle difference (deg) and the horizontal axis represents time (s).

[0059] 4 to 6, the graphs on the right side show the change over time in the q-axis inductance Lq, which is a motor parameter. The top graph shows the estimated q-axis inductance Lq, and the middle graph shows the true (actual) value of the q-axis inductance Lq. The bottom graph shows the parameter error ΔLq, which is the difference between the estimated value and the true value. In the top and middle graphs, the vertical axis is in henrys (mH) and the horizontal axis is time (s). In the bottom graph, the vertical axis is a percentage (%) and the horizontal axis is time (s).

[0060] The forgetting factor λ is a dimensionless value, and is a parameter that can be quantitatively evaluated by treating it in units of response speed (rad / s). ｉｄｎ (rad / s), and the response speed of the induced voltage estimation observer 35 is ω ＯＢＳ (rad / s), and the response speed of the current control unit 24 is ω ＡＣＲ (rad / s) Response speed ω ＯＢＳ is, for example, 2000 rad / s, and the response speed ω ＡＣＲ is, for example, 1500 rad / s.

[0061] In FIG. 3, the response speed ω ｉｄｎ is 40 rad / s, the response speed ω of the induced voltage estimation observer 35 ＯＢＳ The response speed is significantly slower than that of ＯＢＳ / ω ｉｄｎ is 50 times faster. Parameter identification response speed ω ｉｄｎ The changes in the various parameters of the motor 5 when the rotation speed is 40 rad / s are as shown in FIG.

[0062] As shown in FIG. 4, the response speed ω ｉｄｎ When the response speed ω of the parameter identification is 40 rad / s, the left graph and the center graph show that the motor 5 loses synchronism after the load change, and the parameter error of the q-axis inductance Lq diverges. ｉｄｎWhen the rotational speed is 50 rad / s, the position estimation error (Δθ) of the motor 5 is 19°, but the motor 5 does not lose synchronism. Therefore, in the case of FIG. 4, it is desirable to set the forgetting factor λ to a value that does not cause the q-axis inductance Lq to diverge, and ω ＯＢＳ / ω ｉｄｎ is smaller than 50 times, and the response speed ω of the parameter identification ｉｄｎ It was confirmed that it is desirable that the forgetting factor λ is a value faster than 40 rad / s. ｉｄｎ It is calculated by back-calculating using equations (15) and (16).

[0063] In FIG. 3, the response speed ω ｉｄｎ is 1500 rad / s, the response speed ω of the induced voltage estimation observer 35 ＯＢＳ The response speed follows ω ＯＢＳ / ω ｉｄｎ is 1.3 times faster. Also, the response speed of parameter identification ω ｉｄｎ is the response speed ω of the current control unit 24 ＡＣＲ The response speed is the same as that of ＡＣＲ / ω ｉｄｎ is 1. Response speed of parameter identification ω ｉｄｎ The changes in the various parameters of the motor 5 when the rotational speed is 1500 rad / s are shown in FIG.

[0064] As shown in FIG. 6, the response speed ω ｉｄｎ When the rotational speed is 1500 rad / s, the left graph and the center graph show that the motor 5 loses synchronism after the load fluctuation and the rotational speed is stabilized, and the parameter error of the q-axis inductance Lq diverges after the stabilization. For this reason, even in the case of Figure 6, it is desirable to set the forgetting factor λ to a value that does not cause the q-axis inductance Lq to diverge, and ＡＣＲ / ω ｉｄｎ is larger than 1, and the response speed of parameter identification ω ｉｄｎ It has been confirmed that it is desirable for the value to be slower than 1500 rad / s.

[0065] In FIG. 3, the response speed ω ｉｄｎWhen the rotational speed is 1000 rad / s, the position estimation error (Δθ) is the smallest at 4°, and the changes in the various parameters of the motor 5 in this case are as shown in FIG.

[0066] As shown in FIG. 5, the response speed ω ｉｄｎ When the load fluctuation is 1000 rad / s, the left graph and the center graph show that the motor 5 settles after the load fluctuation, the position estimation error (Δθ) is suppressed, and the parameter error of the q-axis inductance Lq also settles without diverging. Therefore, in the case of Figure 5, the forgetting factor λ is an optimized value, and ω ＡＣＲ / ω ｉｄｎ is 1.5 times, and the response speed of parameter identification is ω ｉｄｎ It was confirmed that a value of 1000 rad / s is desirable.

[0067] Furthermore, as shown in FIG. 3, it was confirmed that the response speed of parameter identification is good when the position estimation error (rotational difference Δθ) of the motor 5 is in the range of 4°≦Δθ≦19°.

[0068] In this embodiment, the case where only the q-axis inductance Lq is estimated in the predetermined motor parameter calculation formula described above when there is an error in only the q-axis inductance Lq is illustrated, but if the only motor parameter to be identified is the q-axis inductance Lq, it is possible to simplify the calculation formula for parameter identification. This will be explained in detail below.

[0069] b in formula (5) ２２ [n] is given by equation (17).

[0070]

[0071] Here, assuming that Δθ≒0, b ２２ [n] can be expressed by the following simple formula (18):

[0072]

[0073] In the state equation of the motor 5, the current iq (second line: q-axis side) on the rotation coordinate axis is expressed by the following equation (19).

[0074]

[0075] Substituting equation (18) into equation (19) gives equation (20).

[0076]

[0077] In equation (20), if the parameters other than the q-axis inductance Lq are known, equation (26) can be obtained from equation (21) in which the parameter matrix Θ is a scalar.

[0078]

[0079] Then, the q-axis inductance Lq as a motor parameter obtained from the intermediate variables is given by equation (27).

[0080]

[0081] In this way, it is possible to simplify the equation for calculating the q-axis inductance Lq. By simplifying the equation, the load of calculation processing can be reduced, so that even with a motor control device 10 such as an inexpensive microcomputer, step-out of the motor 5 can be suppressed.

[0082] As described above, the motor control device 10 and the motor control method according to the present embodiment can be understood, for example, as follows.

[0083] A motor control device (10) according to a first aspect is a motor control device (10) that estimates the rotational position of a motor (5), and includes a parameter identification unit (28) that identifies motor parameters related to the motor (5), and a position estimation unit (29) that estimates the rotational position of the motor (5) based on the identified motor parameters, wherein the motor parameters include a forgetting factor λ, which is a calculation parameter related to the responsiveness of parameter identification, as a calculation parameter for calculating a parameter value, and the parameter identification unit (28) performs parameter identification at a response speed of parameter identification found from a time constant calculated based on the forgetting factor λ and a control period Ts related to the control processing of parameter identification, and outputs the identified motor parameters to the position estimation unit (29).

[0084] According to this configuration, the motor parameters can be identified with an appropriate response speed for parameter identification, and therefore the rotational position of the motor can be estimated with high accuracy based on the identified motor parameters.

[0085] In a second aspect, in the motor control device 10 according to the first aspect, the motor parameters include a q-axis inductance Lq, and the forgetting factor λ is a value that prevents the difference (parameter error ΔLq), which is the difference between the actual value and the estimated value of the q-axis inductance Lq, from diverging.

[0086] According to this configuration, even if the load on the motor 5 changes suddenly, the motor 5 can be properly stabilized without losing synchronization.

[0087] As a third aspect, in the motor control device 10 according to the first or second aspect, the position estimator 29 includes an induced voltage estimating observer 35 that estimates an extended induced voltage, and a position estimator 36 that estimates the rotational position of the motor 5 based on the extended induced voltage, and the response speed of the induced voltage estimating observer 35 is set to ω ＯＢＳ (rad / s), and the response speed of the parameter identification is ω ｉｄｎ (rad / s), the forgetting factor λ is ＯＢＳ / ω ｉｄｎ is smaller than 50 times.

[0088] With this configuration, the response speed of the parameter identification unit 28 to the induced voltage estimation observer 35 can be made faster than the response speed at which magnetic saturation causes step-out of the motor 5. Therefore, even if the load fluctuation of the motor 5 becomes abrupt and magnetic saturation occurs, the motor 5 can be appropriately stabilized without stepping out.

[0089] As a fourth aspect, in the motor control device 10 according to any one of the first to third aspects, the forgetting factor λ is set to a value smaller than the response speed ω of the parameter identification. ｉｄｎ is a value that results in a response speed faster than 40 rad / s.

[0090] According to this configuration, the response speed of the parameter identification unit 28 can be set to an appropriate response speed that takes into account the magnetic saturation phenomenon.

[0091] As a fifth aspect, in the motor control device 10 according to any one of the first to fourth aspects, the response speed related to the current control of the motor 5 is set to ω ＡＣＲ (rad / s), and the response speed of the parameter identification is ω ｉｄｎ (rad / s), the forgetting factor λ is ＡＣＲ / ω ｉｄｎ is a value greater than one.

[0092] According to this configuration, the response speed ω of the current control of the motor 5 ＡＣＲ Response speed of parameter identification is faster than ω ｉｄｎ Since the time required for the q-axis inductance Lq to be detected can be slowed down, the change in the q-axis inductance Lq can be properly detected and the divergence of the parameter error ΔLq can be suppressed. Therefore, even after the motor 5 has settled, the motor 5 can be properly controlled without losing synchronization.

[0093] As a sixth aspect, in the motor control device 10 according to any one of the first to fifth aspects, the forgetting factor λ is set to a value smaller than the response speed ω of the parameter identification. ｉｄｎ is a value at which the response speed is slower than 1500 rad / s.

[0094] According to this configuration, the response speed of the parameter identification unit 28 can be set to an appropriate response speed that takes into account the response speed of the current control.

[0095] As a seventh aspect, in the motor control device 10 according to any one of the first to sixth aspects, the forgetting factor λ is a value such that the rotational difference (position estimation error) Δθ, which is the difference between the actual value and the estimated value of the rotational position of the motor 5, is in the range of 4°≦Δθ≦19°.

[0096] According to this configuration, even if the load on the motor 5 changes suddenly, the motor 5 can be properly stabilized without losing synchronization.

[0097] A motor control method according to an eighth aspect is a motor control method executed by a motor control device (10) that estimates the rotational position of a motor (5), in which motor parameters related to the motor (5) are identified, and the rotational position of the motor (5) is estimated based on the identified motor parameters, and the motor parameters include a forgetting factor λ, which is a calculation parameter related to the responsiveness of parameter identification, as a calculation parameter for calculating a parameter value, and parameter identification is performed at a response speed of parameter identification found from a time constant calculated based on the forgetting factor λ and a control period Ts related to the control process of parameter identification.

[0098] According to this configuration, the motor parameters can be identified with an appropriate response speed for parameter identification, and therefore the rotational position of the motor can be estimated with high accuracy based on the identified motor parameters.

[0099] 5 Motor 10 Motor control device 21 Rotational speed control section 22 Torque control section 23 High frequency signal generator 24 Current control section 25, 26, 30 Two-phase / three-phase conversion section 27 PWM control section 28 Parameter identification section 29 Position estimation section 31 System identification section 32 Parameter calculation section 35 Back electromotive force estimation observer 36 Position estimator

Claims

1. A motor control device that estimates the rotational position of a motor, comprising: a parameter identification unit that identifies motor parameters related to the motor; and a position estimation unit that estimates the rotational position of the motor based on the identified motor parameters, wherein the motor parameters include a forgetting factor that is a calculation parameter related to the responsiveness of parameter identification as a calculation parameter for calculating parameter values, and the parameter identification unit performs parameter identification at a response speed of parameter identification calculated from a time constant calculated based on the forgetting factor and a control period related to the control processing of parameter identification, and outputs the identified motor parameters to the position estimation unit.

2. The motor control device according to claim 1, wherein the motor parameters include a q-axis inductance, and the forgetting factor is a value that prevents a difference between an actual value and an estimated value of the q-axis inductance from diverging.

3. The position estimation unit includes an induced voltage estimation observer that estimates an extended induced voltage, and a position estimator that estimates the rotational position of the motor based on the extended induced voltage, and the response speed of the induced voltage estimation observer is set to ω ＯＢＳ (rad / s), and the response speed of the parameter identification is ω ｉｄｎ (rad / s), the forgetting factor is ＯＢＳ / ω ｉｄｎ 2. The motor control device according to claim 1, wherein the value of is smaller than 50 times.

4. The forgetting factor is the response speed ω of the parameter identification ｉｄｎ 4. The motor control device according to claim 3, wherein the response speed is faster than 40 rad / s.

5. The response speed related to the current control of the motor is ω ＡＣＲ (rad / s), and the response speed of the parameter identification is ω ｉｄｎ (rad / s), the forgetting factor is ＡＣＲ / ω ｉｄｎ 2. The motor control device according to claim 1, wherein the value of is greater than one.

6. The forgetting factor is the response speed ω of the parameter identification ｉｄｎ 6. The motor control device according to claim 5, wherein the response speed is slower than 1500 rad / s.

7. A motor control device according to claim 1, wherein the forgetting factor is a value such that the rotational difference Δθ, which is the difference between the actual value and the estimated value of the rotational position of the motor, is in the range of 4°≦Δθ≦19°.

8. A motor control method executed by a motor control device that estimates the rotational position of a motor, comprising: identifying motor parameters related to the motor; and estimating the rotational position of the motor based on the identified motor parameters; the motor parameters include a forgetting factor, which is a calculation parameter related to the responsiveness of parameter identification, as a calculation parameter for calculating a parameter value; and performing parameter identification at a response speed of parameter identification calculated based on the forgetting factor and a control period related to the control processing of parameter identification.

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