Motor control device

Abstract

To stably start a motor regardless of the kind of the motor.SOLUTION: In a motor control device 100a having a synchronous driving mode, which is a driving mode for synchronizing a motor with a rotation phase of a control system coordinate axis based on a speed command value and has a speed increase section and a current adjustment section, and a position sensorless control mode for generating the rotation phase of the control system coordinate axis on the basis of a speed estimation value obtained by performing feedback control of an axis error, a synchronous driving current command value generator 13 adjusts a q-axis current command value by increasing the rotation speed of a motor M up to a predetermined value in the speed increase section, thereafter making a d-axis current command value close to a target command value in the current adjustment section, while performing the feedback control to bring the axis error close to 0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a motor control device. [Background technology]

[0002] One known control method for PMSMs (Permanent Magnet Synchronous Motors) is position sensorless control, which estimates the rotor position of the motor (hereinafter referred to as "position estimation") using the induced voltage generated as the motor rotates. With position sensorless control, errors in position estimation become large when the motor is stopped or when the motor is rotating at extremely low speeds where the induced voltage is small.

[0003] In response to this, there is a technology that provides a "synchronous operation mode" as an operation mode different from the position sensorless control mode, in which the motor is synchronized with the rotation phase of the control system coordinate axis based on the speed command value, and after adjusting the phase of the current vector (hereinafter sometimes referred to as "current phase") so that the axis error is close to 0 in the synchronous operation mode, transitioning the operation mode from the synchronous operation mode to the position sensorless control mode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-029016 Summary of the Invention [Problem to be solved by the invention]

[0005] The above technology, in which the operation mode is switched from synchronous operation mode to position sensorless control mode with only the current phase adjusted in the synchronous operation mode, is applicable to a surface permanent magnet synchronous motor (SPMSM), in which only the q-axis current contributes to torque and the d-axis current does not contribute to torque (in other words, the d-axis current does not generate reluctance torque).This is because, when switching to position sensorless control, in which the d-axis current is adjusted to zero, even if the q-axis current value immediately before switching is set as the initial value, no torque fluctuation occurs in the SPMSM, and motor control does not become unstable.

[0006] However, in an Interior Permanent Magnet Synchronous Motor (IPMSM), which generates reluctance torque, the constant torque curve curves significantly in the first quadrant of the dq coordinate system (in other words, the d-axis current contributes to torque). For this reason, when the above technology is applied to an IPMSM and the motor switches to position sensorless control mode while only the current phase is adjusted in synchronous operation mode, a large value is set as the initial value for the q-axis current. This results in an increase in torque, leading to sudden acceleration of rotation.

[0007] Furthermore, in the case of a motor with large changes in the magnetic saturation characteristics of inductance, in an over-excitation state with large current amplitude (i.e., a state in which a large positive d-axis current is flowing), the initial value of the q-axis current when transitioning to position sensorless control will deviate significantly from the appropriate q-axis current, causing the motor control to become unstable.

[0008] Therefore, the present disclosure proposes a technique that enables stable startup of a motor regardless of the type of motor. [Means for solving the problem]

[0009] The motor control device disclosed herein has two operation modes: a synchronous operation mode, which synchronizes a motor with the rotational phase of a control system coordinate axis based on a speed command value and has a speed increase section and a current adjustment section; and a position sensorless control mode, which generates the rotational phase of the control system coordinate axis based on a speed estimate obtained by feedback control of an axis error. The motor control device also has a synchronous operation current command value generator. After increasing the motor rotation speed to a predetermined rotation speed in the speed increase section, the synchronous operation current command value generator adjusts the q-axis current command value in the current adjustment section by feedback control so as to bring the d-axis current command value closer to a target command value while bringing the axis error closer to zero. [Effects of the Invention]

[0010] According to the present disclosure, stable start-up of a motor is possible regardless of the type of motor. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a motor control device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of the operation of the motor control device according to the first embodiment of the present disclosure. [Figure 3] FIG. 3 is a diagram illustrating an example of the operation of the motor control device according to the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating a configuration example of a motor control device according to a second embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram illustrating a configuration example of a PLL controller according to a second embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram illustrating an example of the operation of the proportional output controller according to the second embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a change in current vector when transitioning to a position sensorless control mode according to the third embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating a configuration example of a sensorless current command value generator according to a third embodiment of the present disclosure. [Figure 9]FIG. 9 is a diagram illustrating an example of the operation of the weighting coefficient generator according to the third embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram illustrating an example of a current vector locus according to the third embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram illustrating an example of the operation of the motor control device according to the third embodiment of the present disclosure. [Figure 12] FIG. 12 is a diagram illustrating an example of the operation of the motor control device according to the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, examples of the present disclosure will be described with reference to the drawings. In the following examples, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0013] [Example 1] <Motor control device configuration> FIG. 1 is a diagram illustrating an example configuration of a motor control device according to a first embodiment of the present disclosure. In FIG. 1, a motor control device 100a includes subtractors 11, 18, and 19, a speed controller 12, a current controller 20, adders 21 and 22, a dq / uvw converter 23, a PWM (Pulse Width Modulation) processor 24, and an IPM (Intelligent Power Module) 25. The IPM 25 is connected to a motor M. Examples of the motor M include PMSMs such as IPMSMs and SPMSMs, and the disclosed technology is applicable to motors with and without magnetic salience, regardless of the type of motor.

[0014] The motor control device 100a also includes a current detector 28, a uvw / dq converter 29, an axis error calculator 30, a PLL (Phase Locked Loop) controller 31a, a position estimator 32, and a decoupling controller .

[0015] The motor control device 100a also has a current command value generator 10, switches SW1, SW2, and SW3, and an operation mode switch 40. The current command value generator 10 has a synchronous operation current command value generator 13 and a sensorless current command value generator 14. Each of the switches SW1, SW2, and SW3 has an A contact and a B contact.

[0016] The operation modes of the motor control device 100a include a synchronous operation mode and a position sensorless control mode. The operation mode switch 40 switches the operation mode of the motor control device 100a between the synchronous operation mode and the position sensorless control mode. When the operation mode is the synchronous operation mode, the operation mode switch 40 operates the synchronous operation current command value generator 13 in the current command value generator 10 while stopping the operation of the sensorless current command value generator 14, and connects the switches SW1, SW2, and SW3 to contact B. When the operation mode is the position sensorless control mode, the operation mode switch 40 operates the sensorless current command value generator 14 in the current command value generator 10 while stopping the operation of the synchronous operation current command value generator 13, and connects the switches SW1, SW2, and SW3 to contact A. The synchronous operation current command value generator 13 generates a current command value when the operation mode is the synchronous operation mode. The sensorless current command value generator 14 generates a current command value when the operation mode is the position sensorless control mode.

[0017] The axis error calculator 30 calculates an axis error Δθ, which is the difference between the dc-qc coordinate axes, which are the control system coordinate axes, and the dq coordinate axes, which are the rotor coordinate axes of the motor M, based on the d-axis current detection value id, the q-axis current detection value iq, the d-axis voltage command value Vd, and the q-axis voltage command value Vq. The axis error Δθ calculated by the axis error calculator 30 is input to the PLL controller 31a and the synchronous operation current command value generator 13.

[0018] The position estimator 32 generates the rotational phase θdq of the dc-qc coordinate axes by integrating the speed information input via the switch SW3. When the operation mode is the synchronous operation mode, the switch SW3 is connected to the contact B, and therefore the speed command value ω * is input as speed information to the position estimator 32. Therefore, in the synchronous operation mode, the speed command value ω * On the other hand, when the operation mode is in the position sensorless control mode, the switch SW3 is connected to the contact A, and therefore the speed estimation value ω, which is an estimate of the electrical angular velocity output from the PLL controller 31a, is input to the position estimator 32 as speed information. Therefore, in the position sensorless control mode, the rotational phase θdq is generated based on the speed estimation value ω obtained by feedback control of the axis error Δθ.

[0019] The current controller 20 calculates the d-axis current command value id * The current controller 20 calculates the d-axis voltage command value Vd_cc before decoupling by proportional-plus-integral control of the d-axis current error id_dif, which is the error between the q-axis current command value iq * and the q-axis current detection value iq, and calculates the q-axis voltage command value Vq_cc before decoupling by proportional-plus-integral control of the q-axis current error iq_dif. For example, the current controller 20 calculates the d-axis voltage command value Vd_cc according to equation (1), and calculates the q-axis voltage command value Vq_cc according to equation (2). In equation (1), Kp_d is the d-axis proportional gain, and Ki_d is the d-axis integral gain, and in equation (2), Kp_q is the q-axis proportional gain, and Ki_q is the q-axis integral gain.

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[0020] The decoupling controller 36 controls the speed command value ω *and the d-axis current command value id * and the q-axis current command value iq * The decoupling controller 36 calculates a d-axis decoupling voltage command value Vd_a for compensating for the d-axis voltage command value Vd_cc based on the speed command value ω * and the d-axis current command value id * and the q-axis current command value iq * and calculates a q-axis decoupling voltage command value Vq_a for compensating for the q-axis voltage command value Vq_cc based on the above. For example, the decoupling controller 36 calculates a d-axis decoupling voltage command value Vd_a according to equation (3), and calculates a q-axis decoupling voltage command value Vq_a according to equation (4). In equations (3) and (4), R is the winding resistance of the motor M, Ld is the d-axis inductance of the motor M, Lq is the q-axis inductance of the motor M, and Ψa is the armature flux linkage of the motor M.

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[0021] Here, the current used to calculate the d-axis decoupling voltage command value Vd_a and the q-axis decoupling voltage command value Vq_a in the decoupling controller 36 is the d-axis current command value id * and q-axis current command value iq * By doing so, it becomes possible to control the motor M even if the current command value changes suddenly. Therefore, in the current adjustment section in the synchronous operation mode described later, the d-axis current command value id * and q-axis current command value iq * Even under conditions where the load changes instantaneously, it is possible to achieve both stable and responsive control of the motor M.

[0022] The adder 21 calculates the final d-axis voltage command value Vd by adding the d-axis non-interacting voltage command value Vd_a to the d-axis voltage command value Vd_cc according to equation (5). The adder 22 calculates the final q-axis voltage command value Vq by adding the q-axis non-interacting voltage command value Vq_a to the q-axis voltage command value Vq_cc according to equation (6). This calculates the d-axis voltage command value Vd and the q-axis voltage command value Vq in which interference between the d and q coordinate axes is cancelled by feedforward.

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[0023] The dq / uvw converter 23 converts the two-phase d-axis voltage command value Vd and q-axis voltage command value Vq output from the adders 21 and 22 into a three-phase U-phase voltage command value Vu, a V-phase voltage command value Vv, and a W-phase voltage command value Vw, based on the rotational phase θdq output from the position estimator 32.

[0024] The PWM processor 24 generates six-phase PWM signals based on the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw, and the PWM carrier signal, and outputs the generated six-phase PWM signals to the IPM 25.

[0025] The IPM 25 generates three-phase AC voltages, U phase, V phase, and W phase, from the DC voltage Vdc based on the six-phase PWM signal output from the PWM processor 24, and applies each of the generated three-phase AC voltages to the U phase, V phase, and W phase of the motor M.

[0026] When the bus current of the IPM 25 is detected using the one-shunt method, the current detector 28 detects the U-phase current value iu, the V-phase current value iv, and the W-phase current value iw of the motor M from the six-phase PWM signals output from the PWM processor 24 and the detected bus current, and outputs the phase current values iu, iv, and iw of each phase to the uvw / dq converter 29. Note that the current detector 28 may also detect the phase current values iu, iv, and iw of each phase using the two-transistor method.

[0027] The uvw / dq converter 29 converts the three-phase U-phase current value iu, V-phase current value iv, and W-phase current value iw into two-phase d-axis current detection value id and q-axis current detection value iq based on the rotational phase θdq output from the position estimator 32.

[0028] The PLL controller 31a performs proportional-plus-integral control of the position error Δθ to calculate a speed estimate ω that will make the position error Δθ 0. The speed estimate ω calculated by the PLL controller 31 is input to the position estimator 32 via the switch SW3, which corrects the rotational phase θdq, and as a result, the position error Δθ can approach 0.

[0029] The subtractor 11 calculates the speed command value ω * The speed error Δω is calculated by subtracting the speed estimate ω from the

[0030] The speed controller 12 performs proportional-integral control on the speed error Δω to obtain a torque command value T * For example, the speed controller 12 generates a torque command value T * In equation (7), Kp_sc is the proportional gain of the speed controller 12, and Ki_sc is the integral gain of the speed controller 12. When the operation mode shifts from the synchronous operation mode to the position sensorless control mode, the speed controller 12 generates the d-axis current command value id * and q-axis current command value iq * Based on the torque command value T * Calculate the initial value of

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[0031] When the operation mode is the position sensorless control mode, the sensorless current command value generator 14 generates a torque command value T based on a constant torque curve, which is a current locus where the torque is constant. * is converted into a current vector on the dq coordinate axes, the sensorless d-axis current command value id_sl *and sensorless q-axis current command value iq_sl * Hereinafter, the sensorless d-axis current command value and the sensorless q-axis current command value may be collectively referred to as the "sensorless current command value."

[0032] Here, the preferred method for generating a sensorless current command value differs depending on whether the motor M is an SPMSM or an IPMSM, so it is preferable to set in advance in the motor control device 100a a method for generating a sensorless current command value according to the type of motor to be controlled. For example, when the motor M is an SPMSM, the sensorless current command value generator 14 generates a sensorless d-axis current command value id_sl on the constant torque curve. * is set to 0, and the sensorless q-axis current command value iq_sl * On the other hand, if the motor M is an IPMSM, the sensorless d-axis current command value id_sl is generated from the intersection of the constant torque curve and the MTPA curve (maximum torque / current control curve) (hereinafter referred to as the "two-curve intersection"). * and sensorless q-axis current command value iq_sl * It is preferable to generate a sensorless current command value as follows: It is also possible to set in the motor control device 100a methods for generating a sensorless current command value for both the case where the motor M is an SPMSM and the case where the motor M is an IPMSM, and select one of the methods depending on the type of motor M.

[0033] For example, when the motor M is an SPMSM, the sensorless current command value generator 14 calculates the sensorless d-axis current command value id_sl in the motor torque equation shown in equation (8). * By substituting 0 into the equation (9), the sensorless q-axis current command value iq_sl * In equations (8) and (9), Pn is the number of pole pairs of the motor M.

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[0034] Furthermore, for example, when the motor M is an IPMSM, the sensorless current command value generator 14 calculates the sensorless d-axis current command value id_sl according to the motor torque equation shown in equation (8) and equation (10). * and the sensorless q-axis current command value iq_sl * Calculate.

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[0035] First, the sensorless d-axis current command value id_sl is calculated from equations (8) and (10). * When it is deleted, the sensorless q-axis current command value iq_sl * Equation (11), which is a quartic equation for

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[0036] One of the real solutions of the quartic equation shown in equation (11) is the sensorless q-axis current command value iq_sl at the intersection of the two curves. * Therefore, the sensorless current command value generator 14 derives the solution of the equation (11) to obtain the sensorless q-axis current command value iq_sl * The solution of the quartic equation can be derived using, for example, Newton's method. The sensorless current command value generator 14 calculates the sensorless q-axis current command value iq_sl using equation (11). * After calculating the sensorless q-axis current command value iq_sl in equation (10), * By substituting the above, the sensorless d-axis current command value id_sl * Calculate.

[0037] When the operation mode is the position sensorless control mode, the switches SW1 and SW2 are connected to the contact A, and therefore the sensorless d-axis current command value id_sl generated by the sensorless current command value generator 14 is * and the sensorless q-axis current command value iq_sl * is the d-axis current command value id input to the subtractors 18 and 19 and the decoupling controller 36. *and q-axis current command value iq * This becomes:

[0038] On the other hand, when the operation mode is the synchronous operation mode, the switches SW1 and SW2 are connected to the contact B, so that the synchronous operation d-axis current command value id_sy generated by the synchronous operation current command value generator 13 is * and synchronous operation q-axis current command value iq_sy * is the d-axis current command value id input to the subtractors 18 and 19 and the decoupling controller 36. * and q-axis current command value iq * This becomes:

[0039] The subtractor 18 calculates the d-axis current command value id * The subtractor 19 calculates the d-axis current error id_dif by subtracting the d-axis current detection value id from the q-axis current command value iq * The q-axis current error iq_dif is calculated by subtracting the q-axis current detection value iq from

[0040] <Motor control device operation> 2 and 3 are diagrams illustrating an example of operation of the motor control device according to the first embodiment of the present disclosure. FIG. 2 illustrates an example of operation under a light load, and FIG. 3 illustrates an example of operation under an overload. When the motor M is started or rotating at a low speed, the induced voltage of the motor M is small, which causes an error in the axis error Δθ calculated by the axis error calculator 30. This error in the axis error Δθ may cause instability in the control of the motor M. Therefore, to raise the rotation speed of the motor M to a level at which position sensorless control can be applied, positioning and synchronous operation are performed before position sensorless control is performed. That is, the operation modes of the motor control device 100a transition from a positioning mode M1 to a synchronous operation mode M2 to a position sensorless control mode M3, in that order, as shown in FIGS. 2 and 3. When the operation mode is positioning mode M1 or synchronous operation mode M2, the operation mode switch 40 operates the synchronous operation current command value generator 13 in the current command value generator 10 while stopping the operation of the sensorless current command value generator 14, and connects the switches SW1, SW2, and SW3 to contact B. As the operation of the sensorless current command value generator 14 stops, the operations of the speed controller 12 and the PLL controller 31a, which are located on the input side of the sensorless current command value generator 14, are also stopped. Furthermore, when the operation mode is position sensorless control mode M3, the operation mode switch 40 operates the sensorless current command value generator 14 in the current command value generator 10 while stopping the operation of the synchronous operation current command value generator 13, and connects the switches SW1, SW2, and SW3 to contact A.

[0041] As shown in Figures 2 and 3, the synchronous operation mode M2 has a speed increase section I1 and a current adjustment section I2, and in the synchronous operation mode M2, the control section transitions from the speed increase section I1 to the current adjustment section I2 in that order.

[0042] When the operation mode is the positioning mode M1 or the synchronous operation mode M2, the switches SW1 and SW2 are connected to the contact B, so that the synchronous operation d-axis current command value id_sy generated by the synchronous operation current command value generator 13 is * and synchronous operation q-axis current command value iq_sy *is the d-axis current command value id input to the subtractors 18 and 19 and the decoupling controller 36. * and q-axis current command value iq * On the other hand, when the operation mode is the position sensorless control mode M3, the switches SW1 and SW2 are connected to the contacts A, and therefore the sensorless d-axis current command value id_sl generated by the sensorless current command value generator 14 is * and sensorless q-axis current command value iq_sl * is the d-axis current command value id input to the subtractors 18 and 19 and the decoupling controller 36. * and q-axis current command value iq * This becomes:

[0043] As shown in FIGS. 2 and 3, in the positioning mode M1, the speed command value ω * is set to 0, and the synchronous operation current command value generator 13 generates the d-axis current command value id * is increased from 0 to a predetermined value id_ini, while the q-axis current command value iq * Set to 0. d-axis current command value id * While the current is increasing, the rotor of the motor M starts to move and is positioned. For example, by setting the current value capable of driving the maximum load as the predetermined value id_ini, the motor M can be started without losing synchronization even when overloaded in the synchronous operation mode M2.

[0044] 2 and 3, in the speed increase section I1, the synchronous operation current command value generator 13 generates the d-axis current command value id * is kept constant at a predetermined value id_ini, and the q-axis current command value iq * While keeping constant at 0, the speed command value ω * is linearly increased from 0 to the predetermined rotation speed ω1. As a result, in the speed increase section I1, the d-axis current command value id * and q-axis current command value iq * While being kept constant, the rotation speed of the motor M increases to a predetermined rotation speed corresponding to the predetermined rotation speed ω1. The predetermined rotation speed ω1 is set in advance to a rotation speed at which it is known that the induced voltage of the motor M can be sufficiently detected, for example, 15 rps.

[0045] Next, in the current adjustment section I2, the speed command value ω * is kept constant at a predetermined rotation speed ω1, the synchronous operation current command value generator 13 generates the d-axis current command value id * and q-axis current command value iq * In the current adjustment section I2, the synchronous operation current command value generator 13 adjusts the d-axis current command value id using the predetermined value id_ini as the initial value. * In the current adjustment section I2, the synchronous operation current command value generator 13 starts adjusting the q-axis current command value iq * The initial value of is set to 0 and the q-axis current command value iq * The d-axis current command value id in the current adjustment section I2 is adjusted. * and q-axis current command value iq * In the current adjustment section I2, the synchronous operation current command value generator 13 adjusts the current vector on the dc-qc coordinate axes to a state close to the current vector in the position sensorless control mode M3 by adjusting the d-axis current command value id * is converged to the target command value id_sy_end at the end point of the current regulation section I2 by using a filter or by linearly decreasing it. The target command value id_sy_end has a positive value close to 0 and is slightly over-excited (id * It is preferable to set it to a value such that

[0046] That is, in the speed increase section I1, the synchronous operation current command value generator 13 sets the d-axis current command value id_ini to a predetermined value id_ini that is greater than the target command value id_sy_end. * In the current adjustment section I2 following the speed increase section I1, the synchronous operation current command value generator 13 sets the d-axis current command value id * is gradually decreased to the target command value id_sy_end.

[0047] Generally, when the motor M is an SPMSM that does not have saliency, the d-axis current command value id on the constant torque curve is *is set to 0, and if the motor M is an IPMSM with salient poles, the position sensorless control is performed based on the intersection of the two curves. On the other hand, in the synchronous operation mode M2, the rotation phase θdq is not corrected based on the speed estimate value ω calculated by the PLL controller 31a, so the d-axis current command value id is set to 0 until the d-axis current at which the current vector amplitude for obtaining the desired torque is minimized. * If the d-axis current command value id is decreased, depending on the response speed of the synchronous operation current command value generator 13 when generating the current command value, the load torque may exceed the output torque, and the motor M may lose synchronization. For this reason, as described above, the d-axis current command value id at the end point of the current adjustment section I2 is decreased. * It is preferable to converge to a slight overexcitation.

[0048] In addition, by setting the target command value id_sy_end at the end of the current adjustment section I2 to a value that is approximately 10% of the rated current vector amplitude of the motor M or the current vector amplitude when the motor M drives the maximum load, the d-axis current command value id * The d-axis current command value id in position sensorless control mode M3 * Since the target command value id_sy_end can be converged to a slight over-excitation while being reasonably close to , it is possible to prevent the motor M from losing synchronization in the current adjustment section I2. For example, if the rated current vector amplitude is about 10 A, it is preferable to set the target command value id_sy_end to about 1 A.

[0049] In the current adjustment section I2, the synchronous operation current command value generator 13 controls the axis error Δθ by integral or proportional integral control, thereby obtaining the q-axis current command value iq * When the axis error Δθ is positive, the synchronous operation current command value generator 13 generates the q-axis current command value iq * When the axis error Δθ is negative, the q-axis current command value iq * In this way, in the current adjustment section I2, the synchronous operation current command value generator 13 reduces the q-axis current command value iq by feedback control so as to bring the axis error Δθ closer to zero. * In the current adjustment section I2, the synchronous operation current command value generator 13 adjusts the q-axis current command value iq according to, for example, equation (12).* In equation (12), Ki_iq is the integral gain.

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[0050] In the position sensorless control mode M3, when the axis error Δθ is positive, the PLL controller 31a reduces the speed estimate ω so that the speed estimate ω becomes equal to the speed command value ω. * Since the torque command value T * is increased, and the sensorless current command value generator 14 generates the q-axis current command value iq * On the other hand, in the synchronous operation mode M2, the speed command value ω * is directly input to the position estimator 32, the synchronous operation current command value generator 13 directly calculates the q-axis current command value iq * Therefore, the d-axis current command value id at the start point of the current adjustment section I2 is adjusted. * The desired response speed of the synchronous operation current command value generator 13 can be obtained by adjusting the integral gain Ki_iq (equation (12)) according to the magnitude of the predetermined value id_ini, which is the initial value of the motor M, the inertia of the motor M, the induced voltage constant of the motor M, or the characteristics of the load driven by the motor M.

[0051] When transitioning from the current adjustment section I2 to the position sensorless control mode M3, the speed controller 12 calculates the d-axis current command value id * and q-axis current command value iq * (That is, the d-axis current command value id in synchronous operation mode M2 * and the q-axis current command value iq in synchronous operation mode M2. * The torque command value T * and the torque command value T calculated according to equation (13) * is the initial value of the proportional-integral control for the speed error Δω (i.e., the torque command value T *By doing so, the torque command value T when the operation mode is switched from the synchronous operation mode M2 to the position sensorless control mode M3 is * Since the occurrence of discontinuity can be prevented, the switching shock that occurs in the motor M when the operation mode is switched can be reduced.

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[0052] Furthermore, the torque command value T calculated according to equation (13) * is used as the initial value of the proportional-integral control for the speed error Δω, so in the position sensorless control mode M3, the sensorless d-axis current command value id_sl generated by the sensorless current command value generator 14 is * is adjusted to a value smaller than the target command value id_sy_end, as shown in Figures 2 and 3. For example, when the target command value id_sy_end has a positive value close to 0, the sensorless d-axis current command value id_sl * is adjusted to a value less than or equal to 0.

[0053] As described above, by converging the d-axis current command value to near zero during synchronous operation while generating the q-axis current command value by feedback-controlling the axial error, it is possible to transition from synchronous operation to position sensorless control with the axial error adjusted to near zero and the degree of overexcitation suppressed. This reduces the change in the current vector after transitioning to position sensorless control, thereby reducing switching shock caused by current jumps, speed jumps, etc. when transitioning to position sensorless control, even in an IPMSM or other motor with saliency. This improves the control stability of motor M when transitioning to position sensorless control mode, regardless of the type of motor M, such as whether it has saliency. This enables stable startup of motor M regardless of the type of motor M.

[0054] The first embodiment has been described above.

[0055] [Example 2] In the first embodiment, the synchronous operation mode is switched to the position sensorless control mode while the degree of overexcitation is suppressed by reducing the d-axis current command value in the synchronous operation mode. Furthermore, in the first embodiment, a small d-axis current is applied at the end of the current adjustment interval (i.e., at the start of the position sensorless control mode), thereby reducing the risk of motor M losing synchronization. However, if the load connected to motor M fluctuates periodically, or if the motor constants set for motor M deviate from their true values due to changes in the temperature of motor M or the current value flowing through motor M, there is a risk that motor M may lose synchronization during the process of reducing the d-axis current command value.

[0056] Therefore, in the second embodiment, the concern of the motor M losing synchronization in the current adjustment section in the synchronous operation mode is further reduced. Below, the points that differ from the first embodiment will be described.

[0057] <Motor control device configuration> 4 is a diagram illustrating an example of the configuration of a motor control device according to a second embodiment of the present disclosure. In FIG. 4, a motor control device 100b includes a PLL controller 31b and an adder 41.

[0058] The PLL controller 31b receives the axis error Δθ from the axis error calculator 30. In the synchronous operation mode, the PLL controller 31b calculates the speed command value ω * and outputs the calculated speed correction value ωb. In addition, in the position sensorless control mode, the PLL controller 31b calculates a speed estimation value ω based on the axis error Δθ and outputs the calculated speed estimation value ω.

[0059] The adder 41 calculates the speed command value ω * and the speed correction value ωb to calculate the speed sum value ω+ to be input to the position estimator 32.

[0060] When the operation mode is the synchronous operation mode, the position estimator 32 generates the rotational phase θdq by integrating the speed addition value ω+. On the other hand, when the operation mode is the sensorless control mode, the position estimator 32 generates the rotational phase θdq by integrating the estimated speed ω, similar to that in the first embodiment.

[0061] <Configuration of PLL Controller> FIG. 5 is a diagram showing a configuration example of the PLL controller according to the second embodiment of the present disclosure. In FIG. 5, the PLL controller 31b includes a proportional-integral controller 311, a proportional controller 312, a proportional output controller 313, and a switch SW4.

[0062] The proportional controller 312 calculates a speed variation component ωa representing the speed variation due to the periodic variation of the load connected to the motor M by proportionally controlling the axis error Δθ.

[0063] The proportional output controller 313 calculates a gradually increasing speed correction value ωb by multiplying the speed variation component ωa by a time-varying proportional output coefficient R.

[0064] Similar to the PLL controller 31a in the first embodiment, the proportional-integral controller 311 calculates the estimated speed ω by proportionally integrating the axis error Δθ.

[0065] The switch SW4 has an A contact and a B contact. The operation mode switch 40 connects the switch SW4 to the contact B when the operation mode is the synchronous operation mode, and connects the switch SW4 to the contact A when the operation mode is the sensorless control mode. Therefore, when the operation mode is the synchronous operation mode, the speed correction value ωb is output from the PLL controller 31b, and when the operation mode is the sensorless control mode, the estimated speed ω is output from the PLL controller 31b.

[0066] <Operation of PLL Controller> FIG. 6 is a diagram showing an operation example of the proportional output controller according to the second embodiment of the present disclosure.

[0067] As described above, the proportional output controller 313 calculates the speed correction value ωb by multiplying the speed fluctuation component ωa, which is the proportional output, by the proportional output coefficient R, which gradually increases over time. As shown in FIG. 6 , the proportional output coefficient R increases linearly from 0 to 1 between the start point TA of the section (hereinafter sometimes referred to as the “proportional output adjustment section”) in which the magnitude of the speed correction value ωb is adjusted by multiplying the speed fluctuation component ωa by the proportional output coefficient R. For example, the start point of the current adjustment section I2 may be set as the start point TA, and the end point of the current adjustment section I2 may be set as the end point TB. Alternatively, the proportional output coefficient R may be increased to 1 when the axis error Δθ is adjusted to approximately 0, without actually setting up a current adjustment section. That is, the start point TA may be set as the point in the current adjustment section when the axis error Δθ is adjusted to approximately 0, and the proportional output coefficient R may be increased to 1 immediately after the start point TA, to reach the end point TB.

[0068] The speed correction value ωb is calculated by multiplying the speed fluctuation component ωa by the proportional output coefficient R shown in FIG. 6, and the speed correction value ωb gradually increases from 0 as time passes.

[0069] By adjusting the magnitude of the speed correction value ωb in the current adjustment section as described above, the proportional response of the PLL control is kept small at the beginning of the current adjustment section, when the d-axis current command value is large and there is little risk of motor M losing synchronization. This prevents sudden deceleration of motor M. On the other hand, at the end of the current adjustment section, when the d-axis current command value is small and there is a high risk of motor M losing synchronization, the axis error Δθ has converged to near zero, so increasing the proportional response of the PLL control does not pose a problem. Therefore, by increasing the proportional output coefficient R at the end of the current adjustment section or when the axis error Δθ has converged to near zero, it is possible to generate a rotation phase that corresponds to fluctuations in the motor M's speed. This makes it possible to instantaneously correct the rotation phase of the dc-qc coordinate axes in response to fluctuations in the motor M's speed. This prevents motor M from losing synchronization due to periodic load fluctuations or deviations from the true value of the motor constants when the d-axis current command value decreases.

[0070] The second embodiment has been described above.

[0071] [Example 3] When an IPMSM having saliency is started under an overload, the current vector at the intersection of the constant torque curve corresponding to the load torque and the MTPA curve deviates from the final current vector during synchronous operation, as shown in Fig. 7. Fig. 7 is a diagram illustrating the change in the current vector when transitioning to a position sensorless control mode in the third embodiment of the present disclosure.

[0072] As shown in Figure 7, the greater the overload, the greater the deviation of the current vectors between the synchronous operation mode and the position sensorless control mode. Therefore, as shown in Figures 2 and 3, the greater the overload, the greater the degree of discontinuity in the d-axis current command value and the q-axis current command value when the operation mode is switched from the synchronous operation mode M2 to the position sensorless control mode M3. This raises concerns that switching the operation mode may cause a switching shock in the motor M, which may destabilize the control of the motor M.

[0073] Therefore, in the third embodiment, concerns about instability in the control of the motor M are reduced. The following describes the differences from the first embodiment.

[0074] <Configuration of sensorless current command value generator> 8 is a diagram illustrating a configuration example of a sensorless current command value generator according to a third embodiment of the present disclosure. In FIG. 8, the sensorless current command value generator 14 includes a weighting coefficient generator 141, an MTPA current command value generator 142, a synchronous operation final current command value generator 143, multipliers 144, 145, 146, and 147, and adders 148 and 149.

[0075] The MTPA current command value generator 142 performs the processing performed by the sensorless current command value generator 14 in the first embodiment only for MTPA control, thereby * Based on the MTPA_d-axis current command value id_mt * and MTPA_q-axis current command value iq_mt *That is, the MTPA current command value generator 142 generates the torque command value T * Based on this, the MTPA_d-axis current command value id_mt * and MTPA_q-axis current command value iq_mt * Hereinafter, the MTPA_d-axis current command value and the MTPA_q-axis current command value may be collectively referred to as the "MTPA current command value."

[0076] The synchronous operation final current command value generator 143 generates a final point d-axis current command value id_sy_end, which is the d-axis current command value at the end of the current adjustment section I2 (i.e., the end point of the synchronous operation mode M2). * The synchronous operation final current command value generator 143 generates the final point d-axis current command value id_sy_end * and torque command value T * Based on this, the final point q-axis current command value iq_sy_end is calculated according to equation (14). * The final q-axis current command value iq_sy_end is generated according to equation (14). * is the d-axis current command value on the dc-qc coordinate axis. * The final point d-axis current command value and the final point q-axis current command value are values that lie on a straight line parallel to the qc-axis fixed at θ and fluctuate according to changes in the load torque. Hereinafter, the final point d-axis current command value and the final point q-axis current command value may be collectively referred to as the "final point current command value."

number

[0077] In addition, when it is known in advance by an experiment or the like that the load torque does not change suddenly in the section where the current command value is switched from the final point current command value to the MTPA current command value (hereinafter, sometimes referred to as the "current vector smoothing section"), the synchronous operation final current command value generator 143 sets the final point q-axis current command value iq_sy_end according to equation (14). * As with the d-axis current command value, the q-axis current command value at the end of the current regulation section I2 is set to the final point q-axis current command value iq_sy_end * It is also possible to do so.

[0078] The weighting coefficient generator 141 generates a first weighting coefficient W_up and a second weighting coefficient W_down by which the MTPA current command value and the final point current command value are multiplied, respectively.

[0079] The multiplier 144 multiplies the MTPA_d-axis current command value id_mt * is multiplied by the first weighting coefficient W_up.

[0080] The multiplier 145 calculates the MTPA_q-axis current command value iq_mt * is multiplied by the first weighting coefficient W_up.

[0081] The multiplier 146 calculates the final point d-axis current command value id_sy_end * is multiplied by the second weighting factor W_down.

[0082] The multiplier 147 calculates the final point q-axis current command value iq_sy_end * is multiplied by the second weighting factor W_down.

[0083] The adder 148 adds the multiplication result of the multiplier 144 and the multiplication result of the multiplier 146 to calculate the sensorless d-axis current command value id_sl in the current vector smoothing section. * Generate.

[0084] An adder 149 adds the multiplication result of the multiplier 145 and the multiplication result of the multiplier 147 to calculate a sensorless q-axis current command value iq_sl in the current vector smoothing section. * Generate.

[0085] In other words, the sensorless d-axis current command value id_sl in the current vector smoothing section * is generated according to equation (15), and the sensorless q-axis current command value iq_sl in the current vector smoothing section * is generated according to equation (16).

number

number

[0086] Therefore, when the operation mode is the position sensorless control mode, the MTPA current command value is calculated based on the intersection of the two curves, and corresponds to a first provisional current command value calculated before the final sensorless current command value is calculated by adders 148 and 149. Furthermore, when the operation mode is the position sensorless control mode, the final point current command value is calculated based on the d-axis current command value at the final point of the current adjustment section I2, and corresponds to a second provisional current command value calculated before the final sensorless current command value is calculated by adders 148 and 149.

[0087] <Operation of the sensorless current command generator> 9 is a diagram illustrating an example of the operation of the weighting coefficient generator according to the third embodiment of the present disclosure. As shown in Fig. 9, the weighting coefficient generator 141 generates a first weighting coefficient W_up that increases linearly from 0 to 1 between the start point TX of the current vector smoothing interval and the end point TY of the current vector smoothing interval. The weighting coefficient generator 141 also generates a second weighting coefficient W_down that decreases linearly from 1 to 0 between the start point TX and the end point TY.

[0088] Here, the current vector smoothing section can be set arbitrarily. For example, the current vector smoothing section is set as follows: * It is preferable that the setting be made within a position sensorless control mode section, such as a section where increases from ω1 to ω2. Figures 11 and 12 are diagrams illustrating an example of the operation of the motor control device according to the third embodiment of the present disclosure.

[0089] 10 is a diagram illustrating an example of a current vector locus according to the third embodiment of the present disclosure. * and sensorless q-axis current command value iq_sl *is generated in accordance with equations (15) and (16) using the first weighting coefficient W_up and the second weighting coefficient W_down, so that the continuity of the current vector is maintained even when the operation mode transitions from the synchronous operation mode to the position sensorless control mode, as shown in Fig. 10. Therefore, as shown in Figs. 11 and 12, the continuity of the d-axis current command value and the q-axis current command value is maintained when the operation mode is switched from the synchronous operation mode M2 to the position sensorless control mode M3. As a result, switching shock due to current jumps, speed jumps, etc., when transitioning to the position sensorless control mode can be reduced, thereby further improving the stability of control of the motor M when transitioning to the position sensorless control mode.

[0090] The third embodiment has been described above.

[0091] The third embodiment can also be implemented in combination with the second embodiment.

[0092] As described above, the motor control device (motor control devices 100a and 100b of the embodiments) of the present disclosure has a synchronous operation mode having a speed increase section and a current adjustment section, and a position sensorless control mode. In the synchronous operation mode, the motor (motor M of the embodiments) is synchronized with the rotational phase of the control system coordinate axes based on the speed command value. In the position sensorless control mode, the rotational phase of the control system coordinate axes is generated based on a speed estimate obtained by feedback control of the axis error. The motor control device of the present disclosure also has a synchronous operation current command value generator (synchronous operation current command value generator 13 of the embodiments). The synchronous operation current command value generator increases the motor rotational speed to a predetermined rotational speed (a predetermined rotational speed corresponding to the predetermined rotational speed ω1 of the embodiments) in the speed increase section, and then, in the current adjustment section, adjusts the q-axis current command value by feedback control so that the axis error approaches zero while bringing the d-axis current command value closer to the target command value (target command value id_sy_end of the embodiments).

[0093] Furthermore, the motor control device (motor control devices 100a and 100b of the embodiments) of the present disclosure includes a position sensorless current command value generator (sensorless current command value generator 14 of the embodiments). The synchronous operation current command value generator sets the d-axis current command value to a predetermined value (predetermined value id_ini of the embodiments) that is greater than the target command value in the speed increase section. The position sensorless current command value generator adjusts the d-axis current command value to a value smaller than the target command value in the position sensorless control mode.

[0094] Furthermore, the synchronous operation current command value generator brings the d-axis current command value closer to a target command value having a positive value near 0 in the synchronous operation mode, and the position sensorless current command value generator adjusts the d-axis current command value to a value equal to or less than 0 in the position sensorless control mode.

[0095] Furthermore, the motor control device (motor control devices 100a and 100b of the embodiment) of the present disclosure includes a speed controller (speed controller 12 of the embodiment). When the operation mode transitions from the synchronous operation mode to the position sensorless control mode, the speed controller sets an initial value of the torque command value to bring the difference between the speed command value and the estimated speed value closer to zero, based on the final value of the d-axis current command value in the synchronous operation mode and the final value of the q-axis current command value in the synchronous operation mode.

[0096] Furthermore, the motor control device (motor control device 100b of the embodiment) of the present disclosure includes a PLL controller (PLL controller 31b of the embodiment) and a position estimator (position estimator 32 of the embodiment). In the current adjustment period, the PLL controller calculates a speed fluctuation component (speed fluctuation component ωa of the embodiment) by proportionally controlling the axis error and calculates a speed correction value based on the speed fluctuation component, while in the position sensorless control mode, it calculates a speed estimated value by proportional-plus-integral control of the axis error. In the current adjustment period, the position estimator generates a rotation phase based on a speed command value and a speed correction value, while in the position sensorless control mode, it generates the rotation phase by integrating the speed estimated value.

[0097] Furthermore, in the current adjustment section, the PLL controller calculates a speed correction value by multiplying the speed fluctuation component by a coefficient that increases with the passage of time.

[0098] The position sensorless current command value generator includes a first current command generator (MTPA current command value generator 142 in the embodiment), a second current command generator (synchronous operation final current command value generator 143 in the embodiment), and a coefficient generator (weighting coefficient generator 141 in the embodiment). The first current command generator generates a first tentative current command value (MTPA current command value in the embodiment) in the position sensorless control mode. The second current command generator generates a second tentative current command value (final point current command value in the embodiment) based on the d-axis current command value immediately before the operation mode transitions from the synchronous operation mode to the position sensorless control mode. The coefficient generator generates an increase coefficient (first weighting coefficient W_up in the embodiment) that increases from 0 to 1 from the start to the end of the smoothing interval (current vector smoothing interval in the embodiment) set within the interval in which the operation mode is the position sensorless control mode, and a decrease coefficient (second weighting coefficient W_down in the embodiment) that decreases from 1 to 0 from the start to the end of the smoothing interval. Then, the position sensorless current command value generator generates a current command value in the position sensorless control mode by adding the product of the first tentative current command value and the increase coefficient to the product of the second tentative current command value and the decrease coefficient. [Explanation of symbols]

[0099] 100a, 100b Motor control device 12 Speed Controller 13 Synchronous operation current command generator 14 Sensorless current command generator 31a, 31b PLL controller 32 Position estimator 141 Weighting Factor Generator 142 MTPA current command generator 143 Synchronous operation final current command generator

Claims

1. A motor control device having a synchronous operation mode in which a motor is synchronized with a rotational phase of a control system coordinate axis based on a speed command value, the synchronous operation mode having a speed increase section and a current adjustment section, and a position sensorless control mode in which the rotational phase of the control system coordinate axis is generated based on a speed estimate value obtained by feedback control of an axis error, a synchronous operation current command value generator that, after increasing the rotational speed of the motor to a predetermined rotational speed in the speed increase section, adjusts a q-axis current command value by performing feedback control so that the axis error approaches zero while bringing a d-axis current command value closer to a target command value in the current adjustment section, the synchronous operation current command value generator sets the d-axis current command value to a predetermined value greater than the target command value in the speed increase section, a position sensorless current command value generator that adjusts the d-axis current command value to a value smaller than the target command value in the position sensorless control mode. Motor control device.

2. the synchronous operation current command value generator, in the synchronous operation mode, causes the d-axis current command value to approach the target command value having a positive value close to 0; the position sensorless current command value generator adjusts the d-axis current command value to a value equal to or less than 0 in the position sensorless control mode; The motor control device according to claim 1 .

3. A motor control device having a synchronous operation mode in which a motor is synchronized with a rotational phase of a control system coordinate axis based on a speed command value, the synchronous operation mode having a speed increase section and a current adjustment section, and a position sensorless control mode in which the rotational phase of the control system coordinate axis is generated based on a speed estimate value obtained by feedback control of an axis error, a synchronous operation current command value generator that, after increasing the rotational speed of the motor to a predetermined rotational speed in the speed increase section, adjusts a q-axis current command value by performing feedback control so that the axis error approaches zero while bringing a d-axis current command value closer to a target command value in the current adjustment section; a speed controller that, when an operation mode transitions from the synchronous operation mode to the position sensorless control mode, sets an initial value of a torque command value based on a final value of the d-axis current command value in the synchronous operation mode and a final value of the q-axis current command value in the synchronous operation mode, so as to bring a difference between the speed command value and the speed estimation value closer to zero; A motor control device comprising:

4. A motor control device having a synchronous operation mode in which a motor is synchronized with a rotational phase of a control system coordinate axis based on a speed command value, the synchronous operation mode having a speed increase section and a current adjustment section, and a position sensorless control mode in which the rotational phase of the control system coordinate axis is generated based on a speed estimate value obtained by feedback control of an axis error, a synchronous operation current command value generator that, after increasing the rotational speed of the motor to a predetermined rotational speed in the speed increase section, adjusts a q-axis current command value by performing feedback control so that the axis error approaches zero while bringing a d-axis current command value closer to a target command value in the current adjustment section; a PLL controller that calculates a speed fluctuation component by proportionally controlling the axis error in the current adjustment section, calculates a speed correction value based on the speed fluctuation component, and calculates the speed estimation value by proportional-plus-integral control of the axis error in the position sensorless control mode; a position estimator that generates the rotational phase based on the speed command value and the speed correction value in the current adjustment section, and generates the rotational phase by integrating the speed estimated value in the position sensorless control mode; A motor control device comprising:

5. the PLL controller calculates the speed correction value by multiplying the speed fluctuation component by a coefficient that increases with time in the current adjustment section; The motor control device according to claim 4.

6. A motor control device having a synchronous operation mode in which a motor is synchronized with a rotational phase of a control system coordinate axis based on a speed command value, the synchronous operation mode having a speed increase section and a current adjustment section, and a position sensorless control mode in which the rotational phase of the control system coordinate axis is generated based on a speed estimate value obtained by feedback control of an axis error, a synchronous operation current command value generator that, after increasing the rotational speed of the motor to a predetermined rotational speed in the speed increase section, adjusts a q-axis current command value by performing feedback control so that the axis error approaches zero while bringing a d-axis current command value closer to a target command value in the current adjustment section; a position sensorless current command value generator; Equipped with The position sensorless current command value generator a first current command generator that generates a first temporary current command value in the position sensorless control mode; a second current command generator that generates a second tentative current command value based on a d-axis current command value immediately before an operation mode transitions from the synchronous operation mode to the position sensorless control mode; a coefficient generator that generates, in a smoothing section set within a section in which the operation mode is the position sensorless control mode, an increase coefficient that increases from 0 to 1 from the start to the end of the smoothing section and a decrease coefficient that decreases from 1 to 0 from the start to the end of the smoothing section; and the position sensorless current command value generator generates a current command value in the position sensorless control mode by adding a product of the first temporary current command value and the increase coefficient and a product of the second temporary current command value and the decrease coefficient. Motor control device.

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