Motor control device

Abstract

To provide a motor control device which can achieve both reduction of time for a layout and an adjustment of a correction amount of an amplitude and a phase according to a response characteristic, and securing of a torque ripple suppression effect.SOLUTION: A motor control device 1 drives a motor 5 by an inverter 4. The motor control device 1 has a harmonic control command value calculating unit 8 obtaining a first harmonic control command value i*dqh, φ*dqh from a torque command value τ* and an electric angle θe of the motor 5, a response compensation unit 9 calculating a second harmonic control command value i**dqh, φ**dqh obtained by performing a response characteristic compensation according to a revolution of the motor 5 on the first harmonic control command value i*dqh, and a voltage command calculating unit 3 calculating a voltage command value v*dq based on a control command for outputting a torque of the torque command value τ* and the second harmonic control command value i**dqh, φ**dqh.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor control device that suppresses torque ripple generated from a motor during motor control. [Background technology]

[0002] Motors are becoming increasingly powerful for use in applications with limited loading space, such as in automobiles. This has led to motors being used more in the region where magnetic saturation occurs. In the magnetic saturation region, torque ripple increases, inducing vibration and noise, so torque ripple suppression control is particularly required.

[0003] As a conventional device for suppressing the torque ripple of a motor to reduce vibration, for example, there is a technology described in Patent Document 1. The device described in Patent Document 1 creates a table relating to the amplitude and phase of the torque ripple according to the torque generated by the motor, and calculates a torque ripple compensation value corrected so as to suppress the amplitude and phase of the torque ripple by referring to this table, and superimposes it on the command value. This correction makes it possible to suppress the torque ripple at frequencies beyond the torque control band. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5784787 Summary of the Invention [Problem to be solved by the invention]

[0005] When correcting the amplitude and phase of the superimposed torque ripple compensation amount in accordance with the rotation speed, it is necessary to know the response characteristics of the torque.

[0006] However, generally, there is a deviation between the design response value of the FB controller and the actual torque response value due to changes in the motor constants caused by magnetic saturation at high torque, which reduces the accuracy of suppressing torque ripple.

[0007] Therefore, in order to ensure accuracy, it was necessary to adjust or measure the response characteristics for each operating condition, such as torque or current, which made designing the controller time-consuming.

[0008] An object of the present invention is to provide a motor control device that can simultaneously shorten the time required to design and adjust the amount of correction of amplitude and phase according to the response characteristics, and ensure the effect of suppressing torque ripple. The present invention uses a control system for the FB controller that has a robust response to changes in the motor constants, and individually corrects the phase and amplitude of the dq-axis harmonic command values ​​according to the rotation speed. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention is configured as follows.

[0010] A motor control device that drives a motor by an inverter, comprising: a harmonic control command value calculation unit that determines a first harmonic control command value from a torque command value and an electrical angle of the motor; a response compensation unit that calculates a second harmonic control command value by performing response characteristic compensation on the first harmonic control command value in accordance with the rotation speed of the motor; and a voltage command calculation unit that calculates a voltage command value based on a control command for outputting torque of the torque command value and the second harmonic control command value. Effect of the Invention

[0011] The present invention can provide a motor control device that can reduce the time required to design and adjust the amount of correction of amplitude and phase according to the response characteristics, while ensuring the effect of suppressing torque ripple. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic block diagram of a motor control device according to a first embodiment of the present invention. [Diagram 2] 11 is a diagram showing a difference between an actual current and a detected current caused by a current detection delay. FIG. [Diagram 3] FIG. 11 is a schematic block diagram of a motor control device according to a second embodiment of the present invention. [Figure 4A] FIG. 2 is a diagram illustrating conversion from a current to a magnetic flux. [Figure 4B] FIG. 2 is a diagram illustrating conversion from a current to a magnetic flux. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. EXAMPLES

[0014] Example 1 FIG. 1 is a functional block diagram showing a configuration of a motor control device 1 according to a first embodiment of the present invention.

[0015] In the following description, the term "dq-axis" refers to the "d-axis and q-axis." Furthermore, for the subscripted parameters X (such as "i" and "v") described below, unless otherwise specified, "Xdq" refers to "vector quantity (Xd, Xq)" and "Xuvw" refers to "vector quantity (Xu, Xv, Xw)." Here, "uvw" refers to the three phases of AC, that is, "U-phase, V-phase, and W-phase."

[0016] In FIG. 1, a motor control device 1 controls the speed and torque of a motor 5 by controlling the switching of an inverter 4 that supplies AC power to the motor 5.

[0017] In the first embodiment, the motor control device 1 is configured with a processor such as a microcomputer, and functions as each unit by executing a predetermined program.

[0018] In this embodiment, the inverter 4 is a three-phase inverter having a three-phase full-bridge circuit as a main circuit, the three-phase full-bridge circuit being configured with semiconductor switching elements such as IGBTs and MOSFETs.

[0019] In the first embodiment, the motor 5 is a three-phase AC synchronous motor, which is a rotating machine, such as a permanent magnet synchronous motor.

[0020] The motor 5 is not limited to a synchronous machine, and may be an induction machine. The motor 5 is not limited to a rotating machine, and may be a linear motor. The motor 5 may have a power generation function.

[0021] As shown in FIG. 1, the motor control device 1 controls a torque command value 10 (τ * ) is input, and the dq-axis current command value 2 (i * dq ), a voltage command calculation unit 3, an electrical angle detection unit 6, an electrical angular velocity calculation unit 7, a harmonic control command value calculation unit 8, a response compensation unit 9, a voltage command superposition unit 10, a voltage command value dq / three-phase axis converter 11, and a measured current three-phase / dq axis converter 12.

[0022] The torque command value 10 is given from a higher-level controller or operation system.

[0023] The dq-axis current command value 2 is calculated as the dq-axis current required for outputting the torque of a given torque command from the motor 5. Generally, it is determined so that the torque output per current is maximized (MTPA), but the present invention is effective for any current.

[0024] The voltage command calculation unit 3 calculates the dq-axis current detection value i dq and the dq-axis current command value i * dq The dq-axis current detection value i dq is the dq axis current command value i * dq The voltage command value v * dq Generate.

[0025] In the first embodiment, the voltage command calculation unit 3 is configured to connect integrators in series to the d-axis and q-axis of the motor inverse model of the following equation (1), and calculates the d-axis and q-axis current command value i *dq (d-axis current command value i * d and the q-axis current command value i * q ) to obtain the voltage command value v * dq The following is calculated. However, variables with a t at the end of the L subscript, which represents inductance, indicate dynamic inductance, while variables without a t at the end indicate static inductance. Static inductance is a value determined by the ratio of the dq-axis current to the dq-axis magnetic flux, and dynamic inductance indicates the rate of change in magnetic flux near the reference current. When there is no magnetic saturation, dynamic inductance and static inductance are the same, but when there is magnetic saturation, the dynamic inductance and static inductance do not match.

[0026]

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[0027] In equation (1), Vd is the d-axis voltage of motor 5, Vq is the q-axis voltage of motor 5, R is the resistance value of the winding of motor 5, Ld is the d-axis inductance of motor 5, Lq is the q-axis inductance of motor 5, Ldq and Lqd are the interference inductances between the d-axis and q-axis of motor 5, Ke is the induced voltage constant, Ldt is the dynamic inductance of the d-axis of motor 5, Lqt is the dynamic inductance of the q-axis of motor 5, Ldqt and Lqdt are the dynamic interference inductances between the d-axis and q-axis of motor 5, i * d is the d-axis current command value, i * q is the q-axis current command value, ω e is the electrical angular velocity of the motor 5.

[0028] The voltage command calculation unit 3 is not limited to the configuration of the first embodiment, and may use a control configuration obtained by equivalent transformation, or an approximation model that ignores terms with small effects. For example, if use in the magnetic saturation region is not expected, the dynamic inductance and static inductance may be treated as equivalent values, or an integrator and a motor inverse model may be combined to configure a PI controller and a decoupling controller.

[0029] The electrical angle detection unit 6 detects an electrical angle θ based on a rotation position signal from a rotation sensor (not shown) provided in the motor 5. e The rotation sensor calculates and outputs the mechanical angle (θ m ), the electrical angle detector 6 detects the number of pole pairs (p) of the motor 5 and the electrical angle θ e and mechanical angle θ m and the number of pole pairs (p) (θ e =p θ m ) to obtain the electrical angle θ e Calculate.

[0030] The rotation sensor may be a mechanical angle resolver, a hall sensor, a rotary encoder, etc. Alternatively, a general position sensorless control method may be used to estimate the electrical angle from the current or voltage.

[0031] Similar to the electrical angle calculation unit 6, the electrical angle calculation unit 7 calculates the electrical angular velocity ω based on a rotation position signal from a rotation sensor (not shown) provided in the motor 5. e The electrical angle calculation unit 7 calculates and outputs the number of pole pairs (p) of the motor 5 and the electrical angle θ e and mechanical angle θ m and p(θ e =p θ m ) and electrical angle θ e and electrical angular velocity ω e The relationship (ω e = dθ e / dt) to obtain the electrical angular velocity ω e The electrical angle velocity calculation unit 7 calculates the electrical angle θ e Differentiate the electrical angular velocity ω e It may also be comprised of a differentiator that calculates:

[0032] The harmonic control command value calculation unit 8 calculates the torque command value τ * to the first harmonic control command value i * dqh Output.

[0033] The response compensation unit 9 includes a response compensation table or a response compensation function, and calculates the electrical angular velocity ωe The first harmonic control command value i * dqh The second harmonic control command value i ** dqh Output.

[0034] The voltage command value dq / three-phase axis converter 11 (shown as dq / uvw in FIG. 1) converts the voltage command value v * dq Electrical angle θ e The inverter 4 generates a signal for controlling the switching of the inverter 4 by converting the electric angle θ e Instead of θ, the delay time required for the voltage command value to be reflected in the inverter 4 is compensated. ec may also be used.

[0035] The measurement current three-phase / dq axis converter 12 converts the three-phase current detected by the current sensor into θ e Depending on the dq axis current i dq In this case, θ e Instead of θ, which takes into account the current detection delay ed may also be used.

[0036] The operation of the motor control device 1 will be described below, while the effect of the present invention will be described.

[0037] First, the torque command value τ * The harmonic control command value calculation unit 8 receives the first harmonic control command value i * dqh In equation (2), n indicates the order of the torque ripple.

[0038]

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[0039] At this time, the dq axis current I dq , θ dqis obtained in advance by analysis or testing, and the torque command value τ * The function can be found by using a table with θ as an argument. delay is the amount of operation that advances the phase by the delay time that occurs between the detected current and the current actually flowing through the motor 5, and the delay time is T delay Then, nT delay ω e This operation allows the response of the FB controller to be separated from the dead time, and the response compensation table described later can be designed as a simple first-order lag function.

[0040] If the above delay is not corrected, even if the detected current and current command value match, the actual current will deviate from the detected current as shown in Figure 2, causing a current with a phase different from the desired timing to flow, resulting in a decrease in performance. Note that in Figure 2, the detected current and current command value are perfectly consistent, but for the sake of illustration they are shifted from each other.

[0041] dq axis current detection value I dq , θ dq By storing as complex coefficients, it is possible to avoid phase discontinuity when referencing the table.

[0042] The response compensation unit 9 calculates the first harmonic control command value i * dqh For nω e Calculate the electrical angle frequency of the torque ripple. Furthermore, calculate nω from the two-dimensional table of amplitude correction and electrical angle frequency and the two-dimensional table of phase correction and each electrical frequency. e Amplitude correction amount I corresponding to mod and the phase correction amount θ mod In the first embodiment, since the response is designed as a first-order delay system, these two-dimensional tables can be implemented as a function of the following formula (3). However, in formula (3), ω acr is the control response angular frequency.

[0043]

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[0044] At this time, the second harmonic control command value i ** dqh is calculated using the following equation (4).

[0045]

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[0046] The voltage command calculation unit 3 calculates a second harmonic control command value i ** dqh and the dq-axis current command value i * dq The final current command value calculated from the current measurement value and the voltage command value v * dq Calculate.

[0047] If the control response angular frequencies of the d-axis and q-axis are designed to be different, the torque response characteristics require a correction table for amplitude and phase to be stored for each combination of the control response characteristics of the d-axis and q-axis, which takes time to design. On the other hand, in the case of compensation for current, the response characteristics are determined for each axis, so the different control response angular frequencies ω acr It is only necessary to prepare a correction table or function for amplitude and phase for each, thereby ensuring the torque ripple suppression effect while reducing the design man-hours.

[0048] In addition, in this embodiment 1, the torque ripple of a single frequency is targeted in order to explain the operation, but it is also possible to deal with cases including torque ripple of multiple frequencies by performing the same operation for each arbitrary order and adding up the results of all orders at the output stage of the response compensation unit 9. In this case, the response compensation unit 9 calculates the amplitude correction amount I mod and the phase correction amount θ mod is calculated for each order.

[0049] According to the first embodiment, it is possible to provide a motor control device that can achieve both a reduction in the time required for designing and adjusting the amount of correction of amplitude and phase according to the response characteristics and a secure torque ripple suppression effect.

[0050] Example 2 Next, a second embodiment will be described.

[0051] The difference between the second embodiment and the first embodiment will be described with reference to the block diagram of the second embodiment shown in FIG.

[0052] In the second embodiment, the torque command value 10(τ * ), the control command calculation unit 13 outputs the dq-axis current command value 2(i * dq ) and calculate the dq-axis current command value 2(i * dq ) is the magnetic flux command value φ dq and a converter 100 for converting the measured current i dq The measured magnetic flux value φ dq and a converter 101 for converting the torque command value 10(τ * The first harmonic control command value φ is calculated from the harmonic current command value corresponding to * dqh The torque command value 10(τ * ) to the first harmonic control command value φ * dqh a harmonic control command value calculation unit 8 that outputs a first harmonic control command value φ * dqh and electrical angular velocity ω e to the second harmonic control command value φ ** dqh and a response compensation unit 9 for calculating a second harmonic control command value φ ** dqh and the measured magnetic flux value φ dq (d-axis magnetic flux measurement value φ d , q-axis magnetic flux measurement value φ q ) to obtain the voltage command value v * dq The voltage command calculation unit 3 calculates the voltage command.

[0053] First harmonic control command value φ in the second embodiment * dqh and the second harmonic control command value φ ** dqh The physical quantity of is magnetic flux, unlike the current in the first embodiment. However, f in the following equation (5) dis a relationship between current and magnetic flux obtained by prior analysis, testing, etc., and is a function that depends on the current of the dq axis, for example, as shown in Figures 4A and 4B. In this configuration, converter 100 and converter 101 may have the same function, or in the case of a table, a table having different resolutions depending on the required accuracy for the command value and the measured value may be used.

[0054]

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[0055]

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[0056] In equation (6), Vd is the d-axis voltage of the motor 5, Vq is the q-axis voltage of the motor 5, R is the resistance value of the winding of the motor 5, Ld is the d-axis inductance of the motor 5, Lq is the q-axis inductance of the motor 5, Ldq and Lqd are the interference inductances between the d-axis and q-axis of the motor 5, Ke is the induced voltage constant, φ d is the measured magnetic flux value of the d axis, φ q is the measured magnetic flux on the q axis, ω e is the electrical angular velocity of the motor 5.

[0057] The operation of the second embodiment will be explained by comparing it with the first embodiment. By using magnetic flux instead of current, the inverse model of the motor can reduce the number of variables as shown in equation (6) compared to equation (1) for current. This not only provides the same effect as the first embodiment, but also makes it possible to reduce the number of searches and constant tables while taking into account nonlinearity due to magnetic saturation.

[0058] As with the first embodiment, the motor inverse model of equation (6) is not limited to the configuration of the second embodiment, but may use a control configuration obtained by equivalent transformation, or an approximation model that ignores terms with small effects. [Explanation of symbols]

[0059] 1 Motor control device, 2 dq-axis current command value, 3 voltage command calculation unit, 4 inverter, 5 motor, 6 electrical angle detection unit, 7 electrical angular velocity calculation unit, 8 harmonic control command value calculation unit, 9 response compensation unit, 10 torque command value, 11 voltage command value dq / three-phase axis converter, 12 measured current three-phase / dq axis converter, 13 control command calculation unit, 100, 101 converter, i * dqh , φ * dqh 1st harmonic control command value, i ** dqh , φ ** dqh 2nd harmonic control command value, ω e Electrical Angular Velocity

Claims

1. A motor control device that drives a motor by an inverter, a harmonic control command value calculation unit that calculates a first harmonic control command value from a torque command value and an electrical angle of the motor; a response compensation unit that calculates a second harmonic control command value by performing response characteristic compensation on the first harmonic control command value in accordance with a rotation speed of the motor; a voltage command calculation unit that calculates a voltage command value based on a control command for outputting a torque of the torque command value and the second harmonic control command value; A motor control device comprising:

2. 2. The motor control device according to claim 1, The motor control device according to claim 1, wherein the harmonic control command value calculation unit calculates the first harmonic control command value for each harmonic order.

3. 2. The motor control device according to claim 1, The motor control device according to claim 1, wherein the response compensation unit corrects the amplitude and phase of the first harmonic control command value for each order.

4. 2. The motor control device according to claim 1, The voltage command calculation unit is When Vd is the d-axis voltage of the motor, Vq is the q-axis voltage of the motor, R is the resistance value of the winding of the motor, Ld is the d-axis inductance of the motor, Lq is the q-axis inductance of the motor, Ldq and Lqd are the interference inductances between the d-axis and q-axis of the motor, Ke is an induced voltage constant, Ldt is the dynamic inductance of the d-axis of the motor, Lqt is the dynamic inductance of the q-axis of the motor, Ldqt and Lqdt are the dynamic interference inductances between the d-axis and q-axis of the motor, i*d is the d-axis current command value, i*q is the q-axis current command value, and ωe is the electrical angular velocity of the motor, the following formula (1): [0010] The motor control device according to claim 1, wherein the voltage command value is calculated using the above formula.

5. 2. The motor control device according to claim 1, The voltage command calculation unit is When Vd is the d-axis voltage of the motor, Vq is the q-axis voltage of the motor, R is the resistance value of the winding of the motor, Ld is the d-axis inductance of the motor, Lq is the q-axis inductance of the motor, Ldq and Lqd are the interference inductances between the d-axis and q-axis of the motor, Ke is an induced voltage constant, φd is the magnetic flux measurement value of the motor on the d-axis, φq is the magnetic flux measurement value of the motor on the q-axis, and ωe is the electrical angular velocity of the motor, the following formula (6) is obtained: [006] The motor control device according to claim 1, wherein the voltage command value is calculated using the above formula.

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