JP2023051558A - Motor control device - Google Patents

Abstract

To rightly detect a lock state of a motor.SOLUTION: In a motor control device 100 having a synchronous driving mode in which a motor M is synchronized with a rotation phase of a control system coordinate axis based on a speed command value and a position sensorless control mode in which the rotation phase of the control system coordinate axis is generated on the basis of a speed estimation value obtained by adjusting an axis error through feedback control, a synchronous driving current command value generator 13 adjusts a d-axis current command value id* and q-axis current command value iq* to bring an axis error Δθ close to 0, and a lock determiner 52 determines that the motor M is locked when a current amplitude value at q predetermined timing is equal to or more than a threshold in the synchronous driving mode.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to motor control devices.

As one of the PMSM (Permanent Magnet Synchronous Motor) controls, the motor rotor position is estimated (hereinafter position sensorless control is known. In the position sensorless control, position estimation error increases when the motor is stopped or when the motor is rotating at extremely low speeds where the motor induced voltage is small.

On the other hand, as an operation mode different from the position sensorless control mode, a "synchronous operation mode" is provided in which the motor is synchronized with the rotation phase of the control system coordinate axis based on the speed command value, and the axis error becomes close to 0 in the synchronous operation mode. There is a technique for adjusting the phase of the current vector (hereinafter sometimes referred to as the "current phase") as described above, and then shifting the operation mode from the synchronous operation mode to the position sensorless control mode.

Also known is a technique of detecting that the motor is in a non-rotatable state (hereinafter sometimes referred to as a “locked state”) using the motor induced voltage.

JP 2010-029016 A

However, when the motor induced voltage is used to detect the occurrence of a locked state, variations in the motor induced voltage constant (hereafter referred to as the "induced voltage constant") and inverter output errors can cause the locked state to occur. Correct detection may not be possible.

Therefore, the present disclosure proposes a technology capable of correctly detecting the locked state of the motor.

The motor control device of the present disclosure includes a synchronous operation mode in which the motor is synchronized with the rotation phase of the control system coordinate axes based on the speed command value, and a speed estimation value obtained by feedback control of the axis error. and a position sensorless control mode in which the rotation phase is generated. Further, the motor control device of the present disclosure has a synchronous operation current command value generator and a lock determiner. The synchronous operation current command value generator adjusts the current command value so that the axis error approaches zero in the synchronous operation mode. The lock determiner determines that the motor is locked when a current amplitude value at a predetermined timing is equal to or greater than a threshold in the synchronous operation mode.

According to the present disclosure, it is possible to correctly detect the locked state of the motor.

FIG. 1 is a diagram showing a configuration example of a motor control device according to an embodiment of the present disclosure. FIG. 2 is a diagram showing an operation example of the motor control device according to the embodiment of the present disclosure. FIG. 3 is a diagram showing an operation example of the motor control device according to the embodiment of the present disclosure. FIG. 4 is a diagram showing a configuration example of a synchronous operation current command value generator according to an embodiment of the present disclosure. FIG. 5 is a diagram showing an operation example of the motor control device according to the embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described based on the drawings. In the following examples, the same reference numerals are given to the same parts, and redundant description may be omitted.

[Example]
<Configuration of motor control device>
FIG. 1 is a diagram showing a configuration example of a motor control device according to an embodiment of the present disclosure. In FIG. 1, the motor control device 100 includes subtractors 11, 18, 19, a speed controller 12, a current controller 20, adders 21, 22, a dq/uvw converter 23, and a PWM (Pulse Width modulation) processor 24 and an IPM (Intelligent Power Module) 25 . The IPM 25 is connected to the motor M. Examples of the motor M include PMSM such as IPMSM (Interior Permanent Magnet Synchronous Motor) and SPMSM (Surface Permanent Magnet Synchronous Motor).

In addition, the motor control device 100 includes a current detector 28, a uvw/dq converter 29, an axis error calculator 30, a PLL (Phase Locked Loop) controller 31, a position estimator 32, and non-interfering control. a vessel 36;

The motor control device 100 also has a current command value generator 10 , switches SW<b>1 , SW<b>2 , SW<b>3 , an operation mode switcher 40 , a current amplitude calculator 51 , and a lock determiner 52 . 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, SW3 has an A contact and a B contact.

The operation modes of the motor control device 100 include a synchronous operation mode and a position sensorless control mode. The operation mode switcher 40 switches the operation mode of the motor control device 100 between the synchronous operation mode and the position sensorless control mode. The operation mode switcher 40 is controlled by a controller external to the motor control device 100 . When the operation mode is the synchronous operation mode, the operation mode switcher 40 operates the synchronous operation current command value generator 13 in the current command value generator 10 and stops the operation of the sensorless current command value generator 14. At the same time, the switches SW1, SW2, and SW3 are connected to the contact B. When the operation mode is the position sensorless control mode, the operation mode switcher 40 operates the sensorless current command value generator 14 in the current command value generator 10 while operating the synchronous operation current command value generator 13. are stopped, and the switches SW1, SW2, and SW3 are connected to the contact A. A synchronous operation current command value generator 13 generates a current command value when the operation mode is in the synchronous operation mode. A sensorless current command value generator 14 generates a current command value when the operation mode is the position sensorless control mode.

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

The position estimator 32 integrates the speed information input via the switch SW3 to generate the rotational phase θdq of the dc-qc coordinate axes. When the operation mode is the synchronous operation mode, the switch SW3 is connected to the contact B, so that the electrical angular velocity command value input to the motor control device 100 from the outside of the motor control device 100 (for example, a host controller) is A certain speed command value ω ^* is input to the position estimator 32 as speed information. Therefore, in the synchronous operation mode, the motor M is synchronized with the rotation phase θdq generated based on the speed command value ω ^* . On the other hand, when the operation mode is the position sensorless control mode, the switch SW3 is connected to the contact point A, so the estimated speed value ω, which is the estimated value of the electrical angular speed output from the PLL controller 31, is used as the speed information. It is input to the estimator 32 . Therefore, in the position sensorless control mode, the rotation phase θdq is generated based on the speed estimation value ω obtained by feedback-controlling the axis error Δθ.

The current controller 20 performs proportional-integral control on the d-axis current error id_dif, which is the error between the d-axis current command value id ^* and the d-axis current detection value id. calculate. Further, the current controller 20 performs proportional-integral control on the q-axis current error iq_dif, which is the error between the q-axis current command value iq ^* and the q-axis current detection value iq, so that the q-axis voltage command value before decoupling is Calculate Vq_cc. 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.

Based on the speed command value ω ^* , the d-axis current command value id ^* , and the q-axis current command value iq ^* , the decoupling controller 36 performs d-axis decoupling to compensate the d-axis voltage command value Vd_cc. A voltage command value Vd_a is calculated. In addition, the non-interacting controller 36 performs a q-axis non-interference for compensating the q-axis voltage command value Vq_cc based on the speed command value ω ^* , the d-axis current command value id ^* , and the q-axis current command value iq ^*. An interference voltage command value Vq_a is calculated. For example, the decoupling controller 36 calculates the d-axis decoupling voltage command value Vd_a according to equation (3), and calculates the 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. .

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 the q-axis current command By setting the value to iq ^* , it becomes possible to cause the control of the motor M to follow a sudden change in the current command value. Therefore, in the current adjustment section in the synchronous operation mode, which will be described later, even under the condition that the d-axis current command value id ^* and the q-axis current command value iq ^* change instantaneously, the stability and responsiveness of the control of the motor M can be ensured. can be made compatible.

The adder 21 calculates the final d-axis voltage command value Vd by adding the d-axis decoupling voltage command value Vd_a to the d-axis voltage command value Vd_cc in accordance with Equation (5). Further, the adder 22 calculates the final q-axis voltage command value Vq by adding the q-axis decoupling voltage command value Vq_a to the q-axis voltage command value Vq_cc according to equation (6). As a result, the d-axis voltage command value Vd and the q-axis voltage command value Vq in which the interference between the dq coordinate axes is canceled by feedforward are calculated.

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

The PWM processor 24 generates a 6-phase PWM signal based on the U-phase voltage command value Vu, the V-phase voltage command value Vv, the W-phase voltage command value Vw, and the PWM carrier signal. Output the signal to the IPM 25 .

The IPM 25 generates three-phase AC voltages of 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 converts each of the generated three-phase AC voltages are applied to the U-phase, V-phase, and W-phase of the motor M.

When the bus current of the IPM 25 is detected by the one-shunt method, the current detector 28 detects the U-phase current value of the motor M from the six-phase PWM signal output from the PWM processor 24 and the detected bus current. It detects iu, V-phase current value iv, and W-phase current value iw, and outputs phase current values iu, iv, and iw of each phase to uvw/dq converter 29 . The current detector 28 may detect the phase current values iu, iv, and iw of each phase by the 2CT method.

Based on the rotation phase θdq output from the position estimator 32, the uvw/dq converter 29 converts the three-phase U-phase current value iu, the V-phase current value iv, and the W-phase current value iw to the two-phase d-axis The current detection value id and the q-axis current detection value iq are converted.

The PLL controller 31 calculates an estimated speed value ω that makes the axis error Δθ zero by performing proportional integral control on the axis error Δθ. The estimated speed ω calculated by the PLL controller 31 is input to the position estimator 32 via the switch SW3 to correct the rotation phase θdq.

A subtractor 11 calculates a speed error Δω by subtracting the estimated speed value ω from the speed command value ω ^* .

The speed controller 12 generates a torque command value T ^* for bringing the speed error Δω closer to zero by proportional-integral control of the speed error Δω. For example, speed controller 12 generates torque command value T ^* according to equation (7). In equation (7), Kp_sc is the proportional gain of speed controller 12 and Ki_sc is the integral gain of speed controller 12 . In addition, when the operation mode shifts from the synchronous operation mode to the position sensorless control mode, the speed controller 12 adjusts the torque command value T ^* based on the d-axis current command value id ^* and the q-axis current command value iq ^* . calculate.

When the operation mode is the position sensorless control mode, the sensorless current command value generator 14 generates the torque command value T ^* based on a constant torque curve, which is a locus of current in which the torque command value T ^* is constant. A sensorless d-axis current command value id_sl ^* and a sensorless q-axis current command value iq_sl ^* are generated by converting into current vectors on the coordinate axes. Hereinafter, the sensorless d-axis current command value and the sensorless q-axis current command value may be collectively referred to as "sensorless current command value".

Here, when the motor M is an SPMSM, the sensorless current command value generator 14 sets the sensorless d-axis current command value id_sl ^* on the constant torque curve to 0 and generates the sensorless q-axis current command value iq_sl ^* . When the motor M is an IPMSM, the sensorless d-axis current command value id_sl ^* and the sensorless q-axis current command value iq_sl ^* are preferably generated.

For example, when the motor M is an SPMSM, the sensorless current command value generator 14 substitutes 0 for the sensorless d-axis current command value id_sl ^* in the motor torque equation shown in Equation (8), thereby obtaining Equation (9) can obtain the sensorless q-axis current command value iq_sl ^* shown in . In equations (8) and (9), Pn is the number of pole pairs of the motor M.

Further, for example, when the motor M is an IPMSM, the sensorless current command value generator 14 generates the sensorless d-axis current command value id_sl ^* and the sensorless q A shaft current command value iq_sl ^* is calculated.

First, eliminating the sensorless d-axis current command value id_sl ^* from equations (8) and (10) yields equation (11), which is a quartic equation for the sensorless q-axis current command value iq_sl ^* .

Since one of the real number 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, the sensorless current command value generator 14 derives the solution of Equation (11). Thus, the sensorless q-axis current command value iq_sl ^* is calculated. 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), and then substitutes the sensorless q-axis current command value iq_sl ^* into equation (10) to generate the sensorless d-axis A current command value id_sl ^* is calculated.

When the operation mode is the position sensorless control mode, the switches SW1 and SW2 are connected to the contact A, so that the sensorless d-axis current command value id_sl ^* and the sensorless q-axis current command generated by the sensorless current command value generator 14 The value iq_sl ^* becomes the d-axis current command value id ^* and the q-axis current command value iq ^* input to the subtractors 18 and 19 and the non-interacting controller 36, respectively.

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 and the synchronous The operation q-axis current command value iq_sy ^* becomes the d-axis current command value id ^* and the q-axis current command value iq ^* input to the subtractors 18 and 19 and the decoupling controller 36 . When the operation mode is the synchronous operation mode, the synchronous operation d-axis current command value id_sy ^* and the synchronous operation q-axis current command value iq_sy ^* generated by the synchronous operation current command value generator 13 are calculated by the current amplitude calculator 51. is entered in

A subtractor 18 calculates a d-axis current error id_dif by subtracting the d-axis current detection value id from the d-axis current command value id ^* . A subtractor 19 calculates a q-axis current error iq_dif by subtracting the q-axis current detection value iq from the q-axis current command value iq ^* .

The current amplitude calculator 51 calculates the current amplitude value ia_amp according to Equation (12) based on the synchronous operation d-axis current command value id_sy ^* and the synchronous operation q-axis current command value iq_sy ^* .

Note that, instead of the synchronous operation d-axis current command value id_sy ^* and the synchronous operation q-axis current command value iq_sy ^* , the current amplitude calculator 51 provides a value id_LPF obtained by subjecting the d-axis current detection value id to low-pass filtering, and The current amplitude value ia_amp may be calculated according to equation (13) based on the value iq_LPF obtained by performing low-pass filtering on the q-axis current detection value iq. By performing low-pass filter processing on the d-axis current detection value id and the q-axis current detection value iq, the current amplitude value ia_amp can be calculated based on the value from which harmonic components such as noise have been removed. The accuracy of determination by the determiner 52 can be improved.

A lock determiner 52 determines whether or not the motor M is in a locked state based on the current amplitude value ia_amp. When the lock determiner 52 determines that the motor M is in the locked state, the lock determiner 52 outputs a signal LS indicating that the motor M is in the locked state (hereinafter sometimes referred to as a "locked state signal"). Output to the outside of the device 100 (for example, a higher-level controller). Hereinafter, the determination of whether or not the motor M is in the locked state may be referred to as "locked state determination".

<Operation of the motor controller when the motor is not locked>
2 and 3 are diagrams showing an operation example of the motor control device according to the embodiment of the present disclosure. 2 and 3 show an operation example when the motor M is not locked. Further, FIG. 2 shows an example of operation at light load, and FIG. 3 shows an example of operation at overload. When the motor M starts or rotates at low speed, the induced voltage of the motor M is small, so an error occurs in the axis error Δθ calculated by the axis error calculator 30, and the control of the motor M is affected by the error generated in the axis error Δθ. is likely to become unstable. Therefore, in order to increase the rotation speed of the motor M to a rotation speed at which position sensorless control can be applied, positioning and synchronous operation are performed before position sensorless control is performed. That is, as shown in FIGS. 2 and 3, the operation mode of the motor control device 100 shifts to the positioning mode M1, the synchronous operation mode M2, and the position sensorless control mode M3 in this order. When the operation mode is the positioning mode M1 or the synchronous operation mode M2, the operation mode switcher 40 operates the synchronous operation current command value generator 13 in the current command value generator 10, while the sensorless current command value generator 14 operates. is stopped, and the switches SW1, SW2, and SW3 are connected to the contact B. As the operation of the sensorless current command value generator 14 is stopped, the operations of the speed controller 12 and the PLL controller 31 located on the input side of the sensorless current command value generator 14 are also stopped. Further, when the operation mode is the position sensorless control mode M3, the operation mode switcher 40 operates the sensorless current command value generator 14 in the current command value generator 10, while the synchronous operation current command value generator 13 The switches SW1, SW2 and SW3 are connected to the contact A while stopping the operation.

2 and 3, the synchronous operation mode M2 has a speed increase section I1 and a current adjustment section I2. In the synchronous operation mode M2, the control sections are the speed increase section I1 and the current adjustment section It shifts to the order of I2.

Further, 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 generated by the synchronous operation current command value generator 13 id_sy ^* and the synchronous operation q-axis current command value iq_sy ^* become the d-axis current command value id ^* and the q-axis current command value iq ^* input to the subtractors 18 and 19 and the non-interacting controller 36, respectively. On the other hand, when the operation mode is the position sensorless control mode M3, the switches SW1 and SW2 are connected to the contact A, so that the sensorless d-axis current command value id_sl ^* generated by the sensorless current command value generator 14 and the sensorless The q-axis current command value iq_sl ^* becomes the d-axis current command value id ^* and the q-axis current command value iq ^* input to the subtractors 18 and 19 and the non-interacting controller 36 .

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 increases the d-axis current command value id ^* from 0 to a predetermined value id_ini. q-axis current command value iq ^* is set to zero. While the d-axis current command value id ^* is increasing, the rotor of the motor M starts moving and is positioned. For example, by setting a current value capable of driving the maximum load as the predetermined value id_ini, the motor M can be started without stepping out even when the motor M is overloaded in the synchronous operation mode M2. Further, the predetermined value id_ini serves as a guideline for setting a current threshold i_jd used when a lock state determination is performed (hereinafter sometimes referred to as a "lock determination threshold").

2 and 3, in the speed increase section I1, the synchronous operation current command value generator 13 keeps the d-axis current command value id ^* constant at the predetermined value id_ini using the predetermined value id_ini as the initial value. , while the q-axis current command value iq ^* is kept constant at 0, the speed command value ω ^* is linearly increased from 0 to a predetermined rotation speed ω1. As a result, in the speed increase section I1, the d-axis current command value id ^* and the q-axis current command value iq ^* are kept constant, and the rotation speed of the motor M increases to a predetermined rotation speed corresponding to the predetermined rotation speed ω1. rise to a number. The predetermined number of revolutions ω1 is set in advance to a number of revolutions at which it is known that the motor induced voltage can be sufficiently detected, and is, for example, 15 rps.

Next, in the current adjustment section ^{I2, the synchronous operation current command value generator 13 generates the d-axis current command value id* and} the q-axis current command value Adjust iq ^* . In the current adjustment section I2, the synchronous operation current command value generator 13 starts adjusting the d-axis current command value id ^* using the predetermined value id_ini as an initial value. By adjusting the d-axis current command value id ^* and the q-axis current command value iq ^* in the current adjustment section I2, the current vector on the dc-qc coordinate axis changes to the current in the position sensorless control mode M3 in the current adjustment section I2. It is adjusted to a state close to the vector. In the current adjustment section I2, the synchronous operation current command value generator 13 uses a filter or linearly decreases the d-axis current command value id ^* to the target command value id_sy_end at the final point of the current adjustment section I2. converge. The target command value id_sy_end has a positive value near 0, and is preferably set to a value that is slightly overexcited (id ^* >0) than the current vector in the position sensorless control mode M3.

That is, in the speed increase section I1, the synchronous operation current command value generator 13 sets the d-axis current command value id ^* to the predetermined value id_ini having a value larger than the target command value id_sy_end. Also, in the current adjustment section I2 following the speed increase section I1, the synchronous operation current command value generator 13 gradually decreases the d-axis current command value id ^* to the target command value id_sy_end with the predetermined value id_ini as the initial value.

Here, in general, when the motor M is an SPMSM that does not have saliency, position sensorless control is performed with the d-axis current command value id ^* on the constant torque curve set to 0, and the motor M does not have saliency. If the IPMSM has two curves, position sensorless control is performed based on the intersection of the two curves. On the other hand, in the synchronous operation mode M2, since the rotation phase θdq is not corrected based on the speed estimation value ω calculated by the PLL controller 31, the d-axis current that minimizes the current amplitude value for obtaining the desired torque is If the d-axis current command value id ^* is decreased to id*, the load torque may exceed the output torque depending on the response speed when the synchronous operation current command value generator 13 generates the current command value, and the motor M may step out. There is Therefore, as described above, it is preferable to allow the d-axis current command value id ^* at the final point of the current adjustment section I2 to slightly converge to overexcitation.

Further, by setting the target command value id_sy_end at the final point of the current adjustment section I2 to a rated current amplitude value of the motor M or a value of about 10% of the current amplitude value when the motor M drives the maximum load, In the current adjustment section I2, the d-axis current command value id ^* can be brought close to the d-axis current command value id ^* in the position sensorless control mode M3, and the overexcitation can be somewhat converged. motor M can be prevented from stepping out. For example, when the rated current amplitude value is about 10A, the target command value id_sy_end is preferably set to about 1A.

Further, in the current adjustment section I2, the synchronous operation current command value generator 13 generates the q-axis current command value iq ^* by integrating or proportional-integral controlling the axis error Δθ. The synchronous operation current command value generator 13 increases the q-axis current command value iq ^* when the axis error Δθ is positive, and decreases the q-axis current command value iq ^* when the axis error Δθ is negative. Thus, in the current adjustment section I2, the synchronous operation current command value generator 13 adjusts the q-axis current command value iq ^* by feedback control so that the axis error Δθ approaches zero. In the current adjustment section I2, the synchronous operation current command value generator 13 generates the q-axis current command value iq ^* , for example, according to Equation (14). In equation (14), Ki_iq is the integral gain.

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

When shifting from the current adjustment section I2 to the position sensorless control mode M3, the speed controller 12 changes the d-axis current command value id ^* and the q-axis current command value iq ^* at the start of the position sensorless control mode M3 (that is, A torque command value T ^* is calculated according to equation (15) based on the final value of the d-axis current command value id ^* in the synchronous operation mode M2 and the final value of the q-axis current command value iq ^* in the synchronous operation mode M2. , the torque command value T ^* calculated according to the equation (15) is set as the initial value of the proportional integral control for the speed error Δω (that is, the initial value of the torque command value T ^* generated by the speed controller 12). By doing so, it is possible to prevent the occurrence of discontinuity in the torque command value T ^* when the operation mode is switched from the synchronous operation mode M2 to the position sensorless control mode M3. can be reduced.

Further, since the position sensorless control is started with the torque command value T ^* calculated according to the equation (15) as the initial value of the proportional integral control for the speed error Δω, in the position sensorless control mode M3, the sensorless current command value generator 14 The sensorless d-axis current command value id_sl ^* generated by is adjusted to a value smaller than the target command value id_sy_end, as shown in FIGS. For example, when the target command value id_sy_end has a positive value near 0, the sensorless d-axis current command value id_sl ^* is adjusted to a value of 0 or less.

As described above, the d-axis current command value is converged to near 0 in the synchronous operation stage, and the axis error is adjusted to near 0 by generating the q-axis current command value through feedback control of the axis error. It is possible to shift from synchronous operation to position sensorless control in a state in which the degree of overexcitation is suppressed. Therefore, the change in the current vector after shifting to the position sensorless control becomes smaller, so even in the IPMSM having saliency, it is possible to reduce switching shocks due to current jumps, speed jumps, etc. when shifting to the position sensorless control. Therefore, it is possible to improve the stability of the control of the motor M when shifting to the position sensorless control mode regardless of the type of the motor M, ie, whether the motor M has saliency. Therefore, regardless of the type of motor M, the motor M can be stably started.

<Configuration of Synchronous Operation Current Command Value Generator>
FIG. 4 is a diagram showing a configuration example of a synchronous operation current command value generator according to an embodiment of the present disclosure. In FIG. 4 , the synchronous operation current command value generator 13 has a d-axis current command value generator 131 , a q-axis current command value generator 132 and a q-axis current command value limiter 133 .

When the operation mode is the positioning mode M1 or the synchronous operation mode M2, the d-axis current command value generator 131 generates the synchronous operation d-axis current command value id_sy ^* (d-axis current command value id ^* ) is generated.

When the operation mode is the positioning mode M1 or the synchronous operation mode M2, the q-axis current command value generator 132 integrates the axis error Δθ as described with reference to FIGS. Synchronous operation q-axis current command value iq_sy ^* ' before limitation (q-axis current command value iq ^* ) is generated.

The q-axis current command value limiter 133 calculates the q-axis current limit value iq_lim according to Equation (16) based on the predetermined current amplitude limit value ia_lim and the synchronous operation d-axis current command value id_sy ^* .

Further, when the synchronous operation q-axis current command value iq_sy ^* ′ before limitation is equal to or smaller than the q-axis current limit value iq_lim, the q-axis current command value limiter 133 limits the synchronous operation q-axis current command value iq_sy ^* ′ before limitation. is output as it is as the synchronous operation q-axis current command value iq_sy ^* . On the other hand, when the synchronous operation q-axis current command value iq_sy ^* ′ before limitation is greater than the q-axis current limit value iq_lim, the q-axis current command value limiter 133 reduces the q-axis current limit value iq_lim to the synchronous operation q-axis current. Output as command value iq_sy ^* . That is, the q-axis current limit value iq_lim corresponds to the upper limit value for the synchronous operation q-axis current command value iq_sy ^* , and the upper limit of the synchronous operation q-axis current command value iq_sy ^* is limited to the q-axis current limit value iq_lim. By limiting the upper limit of the synchronous operation q-axis current command value iq_sy ^* to the q-axis current limit value iq_lim calculated according to equation (16), the synchronous operation current command value generator 13 outputs the upper limit of the current amplitude value is limited to the current amplitude limit value ia_lim, the synchronous operation q-axis current command value iq_sy ^* is output.

Here, it is preferable that the current amplitude value for driving the motor M at the maximum load when not in the locked state is used as the current amplitude limit value ia_lim. That is, the q-axis current command value limiter 133 preferably uses the current amplitude value when the d-axis current command value id ^* is equal to the predetermined value id_ini as the current amplitude limit value ia_lim.

Further, when the upper limit of the synchronous operation q-axis current command value iq_sy ^* is limited as described above, by limiting the upper limit of the output value of the integrator of the q-axis current command value generator 132, the windup phenomenon can be suppressed.

<Operation of lock determiner>
The lock determiner 52 receives the current amplitude value ia_amp from the current amplitude calculator 51 .

The lock determiner 52 determines whether or not the motor M is in the locked state by comparing the current amplitude value ia_amp with the lock determination threshold i_jd.

Here, the lock determination threshold i_jd is a value smaller than the current amplitude limit value ia_lim. Further, for example, by setting the lock determination threshold value i_jd to a value that is about 5% smaller than the predetermined value id_ini, it is possible to improve the accuracy of lock state determination. For example, when the current amplitude value in the current adjustment section I2 increases due to overload even though the motor M is not in the locked state, it is possible to prevent erroneous determination that the motor M is in the locked state.

The lock determiner 52 determines that the motor M is locked when the current amplitude value ia_amp does not become less than the lock determination threshold value i_jd at a predetermined timing TI after a predetermined time PT has passed since the control section shifted to the current adjustment section I2. Determine that there is. That is, the lock determiner 52 determines that the motor M is locked when the current amplitude value ia_amp at the predetermined timing TI is equal to or greater than the lock determination threshold i_jd. On the other hand, when the current amplitude value ia_amp decreases below the lock determination threshold value i_jd at a predetermined timing TI after a predetermined time PT has passed since the control section shifted to the current adjustment section I2, the lock determiner 52 determines whether the motor M is not in the locked state. That is, the lock determiner 52 determines that the motor M is not locked when the current amplitude value ia_amp at the predetermined timing TI is less than the lock determination threshold i_jd. The lock determiner 52 outputs the lock state signal LS when determining that the motor M is in the locked state, but does not output the lock state signal LS when determining that the motor M is not in the locked state.

For example, when the lock state signal LS is input from the lock determiner 52, the controller external to the motor control device 100 does not shift the operation mode from the synchronous operation mode M2 to the position sensorless control mode M3, and does not change the current adjustment section. Power supply to the motor M is stopped at I2. Here, when the motor M is in the locked state, the motor induced voltage associated with the rotation of the motor M is not generated. Therefore, if the operation mode shifts to the position sensorless control mode M3 while the motor M is in the locked state, the position sensorless control by the axis error calculator 30, the PLL controller 31, and the speed controller 12 becomes unstable. . Therefore, as described above, when the motor M is in the locked state, the power supply to the motor M is stopped before the operation mode shifts to the position sensorless control mode M3. 30, the PLL controller 31, and the speed controller 12 can be prevented from becoming unstable.

Here, the predetermined time PT is set to the same time as the length of the current adjustment section I2, for example. Further, when the winding resistance of the motor M is large and there is concern that the motor M may be damaged due to overheating of the windings, the predetermined time PT is preferably set to a time shorter than the length of the current adjustment section I2. .

As described above, by using the current amplitude value ia_amp instead of the motor induced voltage to determine the lock state, the lock state determination is not affected by variations in the induced voltage constant and inverter output errors. , the locked state of the motor M can be detected correctly.

<Operation of the motor control device when the motor is in the locked state>
FIG. 5 is a diagram showing an operation example of the motor control device according to the embodiment of the present disclosure. FIG. 5 shows an operation example when the motor M is locked.

As described above, lock state determination is performed in the current regulation section I2.

When the motor M is in the locked state, the motor M does not rotate even if the current flowing through the motor M is increased. It works the same as Therefore, when the axis error Δθ is integrated by the q-axis current command value generator 132, the q-axis current command value iq ^* diverges in the process of adjusting the axis error Δθ. As a result, the current amplitude value ia_amp also exhibits an increasing behavior, leading to protective stop of the motor M for suppressing demagnetization of the motor M (hereinafter sometimes referred to as "current trip stop"). If the inertia of the load of the motor M is large, a large acceleration torque may be required even if the motor M is not locked. It is not desirable to reach

Therefore, by using the current amplitude limit value ia_lim when the d-axis current command value id ^* is equal to the predetermined value id_ini as described above, as shown in FIG. The q-axis current command value iq ^* is limited so that the current amplitude value ia_amp in the speed increase section I1 does not exceed the current amplitude value ia_amp in the speed increase section I1. As a result, the motor M can continue to apply torque corresponding to the predetermined value id_ini without stopping the current trip. In other words, it is possible to keep applying a torque sufficient to drive the maximum load in the non-locked state. Therefore, even if the torque corresponding to the maximum load in the non-locked state continues to be applied, if the current amplitude value ia_amp shows an increasing behavior, it is possible to determine that the load of the motor M is greater than the maximum load. Therefore, it can be determined that the motor M is in the locked state.

The embodiments have been described above.

As described above, the motor control device (motor control device 100 of the embodiment) of the present disclosure has a synchronous operation mode and a position sensorless control mode. In the synchronous operation mode, the motor (motor M in the embodiment) is synchronized with the rotation phase of the control system coordinate axes based on the speed command value. In the position sensorless control mode, the rotation phase of the control system coordinate axes is generated based on the speed estimation value obtained by feedback-controlling the axis error. Further, the motor control device of the present disclosure has a synchronous operation current command value generator (synchronous operation current command value generator 13 of the embodiment) and a lock determiner (lock determiner 52 of the embodiment). The synchronous operation current command value generator adjusts the current command values (d-axis current command value id ^* and q-axis current command value iq ^* in the embodiment) so that the axis error approaches zero in the synchronous operation mode. When the current amplitude value (current amplitude value ia_amp in the embodiment) at a predetermined timing (predetermined timing TI in the embodiment) is equal to or greater than a threshold (lock determination threshold i_jd in the embodiment) in the synchronous operation mode, the lock determiner Then, it is determined that the motor is locked.

Also, the threshold value for the current amplitude value is a value smaller than the first upper limit value (current amplitude limit value ia_lim in the embodiment) that is the upper limit value of the current amplitude value.

Also, the synchronous operation mode has a speed increase section and a current adjustment section, and the predetermined timing is in the current adjustment section.

In addition, the synchronous operation current command value generator sets the d-axis current command value to a predetermined value (predetermined value id_ini in the embodiment) in the speed increase section, and sets the rotation speed of the motor to a predetermined rotation speed (predetermined rotation speed in the embodiment). ω1), the d-axis current command value is decreased to a target command value (target command value id_sy_end in the embodiment) having a value smaller than a predetermined value in the current adjustment section, and the axis error is brought close to 0. The q-axis current command value is adjusted by feedback control as follows.

In addition, the synchronous operation current command value generator is the second upper limit value (q-axis current limit value iq_lim in the embodiment) that is the upper limit value of the q-axis current command value, which is calculated based on the first upper limit value The q-axis current command value is limited by the second upper limit value.

Also, the synchronous operation current command value generator uses the current amplitude value when the d-axis current command value is at a predetermined value (predetermined value id_ini in the embodiment) as the first upper limit value.

100 Motor control device 12 Speed controller 13 Synchronous operation current command value generator 14 Sensorless current command value generator 32 Position estimator 51 Current amplitude calculator 52 Lock determiner 131 d-axis current command value generator 132 q-axis current command value Generator 133 q-axis current command value limiter

Claims (6)

A synchronous operation mode that synchronizes the motor with the rotation phase of the control system coordinate axes based on the speed command value, and a position sensorless that generates the rotation phase of the control system coordinate axes based on the speed estimation value obtained by feedback control of the axis error. A motor control device having a control mode,
a synchronous operation current command value generator that adjusts a current command value so that the axis error approaches zero in the synchronous operation mode;
a lock determiner that determines that the motor is locked when a current amplitude value at a predetermined timing is equal to or greater than a threshold in the synchronous operation mode;
A motor control device comprising: The threshold value is a value smaller than a first upper limit value that is the upper limit value of the current amplitude value,
The motor control device according to claim 1. The synchronous operation mode has a speed increase section and a current adjustment section,
wherein the predetermined timing is in the current adjustment interval;
The motor control device according to claim 1. The synchronous operation current command value generator sets the d-axis current command value to a predetermined value in the speed increase section to increase the rotation speed of the motor to a predetermined rotation speed, and then, in the current adjustment section, sets the d-axis current command value to a predetermined value. adjusting the q-axis current command value by reducing the axis current command value to a target command value having a value smaller than the predetermined value and performing feedback control so that the axis error approaches zero;
4. A motor control device according to claim 3. The synchronous operation current command value generator limits the q-axis current command value by a second upper limit value that is the upper limit value of the q-axis current command value,
The second upper limit is calculated based on the first upper limit, which is the upper limit of the current amplitude value,
5. A motor control device according to claim 4. The synchronous operation current command value generator uses the current amplitude value when the d-axis current command value is at the predetermined value as a first upper limit value, which is the upper limit value of the current amplitude value.
5. A motor control device according to claim 4.

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