Motor control device and motor control system

Abstract

This motor control device performs position sensorless vector control using a forward salient-pole model of a synchronous reluctance motor. The motor control device comprises: a velocity control calculation unit that calculates a current command value on the basis of the difference between a velocity command value and a velocity estimation value, the velocity estimation value, and a limit value of a q-axis current command value that is changed according to a proportional gain of velocity estimation; a vector control calculation unit that calculates a voltage command value on the basis of a current detection value, the current command value, and the velocity estimation value; a phase error estimation calculation unit that calculates an estimation value of a phase error on the basis of the voltage command value, the velocity estimation value, and the current detection value; and a frequency and phase estimation calculation unit that calculates the velocity estimation value and a phase estimation value on the basis of the estimation value of the phase error and the velocity command value. Thus, it is possible to automatically select and set parameters related to high efficiency and high responsiveness in the synchronous reluctance motor using a sensorless control system.

Description

Motor control device and motor control system

[0001] The present invention relates to a motor control device and a motor control system.

[0002] Known position sensorless control methods for synchronous reluctance motors include, for example, the one described in Non-Patent Document 1. Non-Patent Document 1 describes a method of estimating a phase error Δθ, which is the phase difference between the reference axis (dc-qc axis) of the control and the magnetic flux axis (d-q axis) of the SynRM, and controlling the estimated value to be "0" (zero).

[0003] Masashi Ichikawa and four others, "Extended Induced Voltage Model in Synchronous Reluctance Motors and Selection Method of Its Main Magnetic Flux Direction," Journal of the Institute of Electrical Engineers of Japan, Vol. 123, No. 12, 2023, pp. 1507-1515

[0004] In the above-described conventional technology, when the phase error Δθ=0 (zero), the motor torque τm is given by the following (Equation 1).

[0005]

[0006] Here, in the above (Equation 1), Pm represents the number of pole pairs, Ld represents the d-axis inductance, Lq represents the q-axis inductance, id represents the d-axis current value, and iq represents the q-axis current value.

[0007] From the above (Equation 1), it can be said that when |id| = |iq|, the current of the synchronous reluctance motor is minimum and the torque is maximum, and that if settings are made so that there is no load (τm = 0) and id = iq = 0, then high efficiency can theoretically be achieved.

[0008] However, the above setting requires a reactive current. Furthermore, since the above-mentioned conventional technique aims to analyze the position estimation error of a position sensorless control system, it does not take into consideration settings for high efficiency or high response.

[0009] The present invention has been made in view of the above, and an object of the present invention is to provide a motor control device and a motor control system that can automatically select and set parameters related to high efficiency and high response in a synchronous reluctance motor of a position sensorless control system.

[0010] The present application includes multiple means for solving the above problems. As one example, a motor control device that performs position sensorless vector control using a forward salient pole model of a synchronous reluctance motor includes: a speed control calculation unit that calculates a current command value based on a difference between a speed command value and a speed estimate value, the speed estimate value, and a limit value; a vector control calculation unit that calculates a voltage command value based on a current detection value, the current command value, and the speed estimate value; a phase error estimation calculation unit that calculates a phase error estimate based on the voltage command value, the speed estimate value, and the current detection value; and a frequency / phase estimation calculation unit that calculates a speed estimate and a phase estimate based on the phase error estimate and the speed command value, wherein the speed control calculation unit uses the limit value of the q-axis current command value that is changed in accordance with a proportional gain of the speed estimation.

[0011] According to the present invention, parameters relating to high efficiency and high response in a synchronous reluctance motor of a position sensorless control system can be automatically selected and set.

[0012] FIG. 1 is a functional block diagram schematically showing the overall configuration of a motor control system according to a first embodiment, together with a motor control device and its related configuration. FIG. 2 is a diagram showing a model of a synchronous reluctance motor. FIG. 3 is a vector diagram of a forward salient pole model. FIG. 4 is a diagram showing simulation results when a ramp signal-shaped load torque is applied. FIG. 5 is a diagram showing simulation results when a ramp signal-shaped load torque is applied. FIG. 6 is a diagram showing a schematic diagram of a case where verification is performed on a synchronous reluctance motor. FIG. 7 is a functional block diagram schematically showing the overall configuration of a motor control system according to a second embodiment, together with a motor control device and its related configuration. FIG. 8 is a functional block diagram schematically showing the overall configuration of a motor control system according to a third embodiment, together with a motor control device and its related configuration. FIG. 9 is a diagram showing the configuration of a high efficiency and high response degree setting unit according to the third embodiment. FIG. 10 is a functional block diagram schematically showing the overall configuration of a motor control system according to a fourth embodiment, together with a motor control device and its related configuration. FIG. 11 is a diagram showing the configuration of a high efficiency and high response degree setting unit according to the fourth embodiment. 10 is a schematic diagram showing the overall configuration of a drive system for a synchronous reluctance motor according to a sixth embodiment.

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

[0014] First Embodiment A first embodiment of the present invention will be described with reference to FIGS.

[0015] FIG. 1 is a functional block diagram showing the overall configuration of a motor control system according to this embodiment, together with a motor control device and its related configuration.

[0016] In FIG. 1, a synchronous reluctance motor 1, which is the object of control by the motor control device, outputs motor torque using a torque component due to the inductance of the armature winding.

[0017] The motor control system is generally composed of a synchronous reluctance motor 1 to be controlled by the motor control device, a current detector 4 that detects three-phase AC currents iu, iv, iw of the synchronous reluctance motor 1 and outputs detected values ​​iuc, ivc, iwc to the motor control device, a motor control device that generates three-phase AC voltage command values ​​Vu*, Vv*, Vw* in accordance with a speed command value ωr* and the detected values ​​iuc, ivc, iwc of the current detector 4 and outputs them to a power converter 2, and a power converter 2 that outputs voltage values ​​proportional to the voltage command values ​​Vu*, Vv*, Vw* from the motor control device to the synchronous reluctance motor 1 and varies the output voltage value and output frequency value of the synchronous reluctance motor 1. A DC power supply 3 is connected to the power converter 2 and supplies a DC voltage used to generate the voltage value output to the synchronous reluctance motor 1.

[0018] In this embodiment, the current detector 4 is configured to detect the AC currents iu, iv, and iw of the three phases of the synchronous reluctance motor 1, but the present invention is not limited to this. For example, the current detector 4 may be configured to detect the AC currents (iu, iw) of two of the three phases of the synchronous reluctance motor 1 (for example, the u-phase and w-phase), and to determine the AC current (iv) of the remaining phase (for example, the v-phase) from the AC condition (iu+iv+iw=0) as iv=-(iu+iw).

[0019] The motor control device has functional units including a coordinate conversion unit 5, a speed control calculation unit 6, a vector control calculation unit 7, a phase error estimation calculation unit 8, a frequency / phase estimation calculation unit 9, and a coordinate conversion unit 10.

[0020] The coordinate conversion unit 5 calculates and outputs the d-axis and q-axis current detection values ​​idc and iqc based on the detection values ​​iuc, ivc, iwc of the three-phase AC currents iu, iv, iw of the synchronous reluctance motor 1 detected by the current detector 4 and the phase estimation value θdc.

[0021] The speed control calculation unit 6 calculates a d-axis current command value id* based on the difference between the speed command value ωr* and the speed estimated value ωdc, and calculates a q-axis current command value iq* using the current command value id* and the speed command value ωr*, and outputs the d-axis and q-axis current command values ​​id* and iq*.

[0022] The vector control calculation unit 7 calculates and outputs voltage command values ​​vdc**, vqc** for the d-axis and q-axis based on the d-axis and q-axis current command values ​​id*, iq*, the current detection values ​​idc, iqc, the speed estimate value ωdc, and the electrical circuit parameters of the synchronous reluctance motor 1.

[0023] The phase error estimation calculation unit 8 calculates and outputs an estimated value Δθc of the phase error Δθ, which is the deviation between the phase estimate θdc of the control axis and the phase θd of the synchronous reluctance motor 1, based on the voltage command values ​​vdc**, vqc** of the dc-axis and qc-axis which are the control axes, the speed estimate ωdc, the detected current values ​​idc, iqc, and the electrical circuit parameters of the synchronous reluctance motor 1.

[0024] The frequency / phase estimation calculation unit 9 calculates and outputs a speed estimate ωdc and a phase estimate θdc based on the phase error estimate Δθc and the speed command value ωr*.

[0025] The coordinate transformation unit 10 calculates and outputs three-phase AC voltage command values ​​vu*, vv*, vw* based on the dc-axis and qc-axis voltage command values ​​vdc**, vqc** and the phase estimate value θdc.

[0026] (Basic Operation) The basic operation of this embodiment will be described. This embodiment is characterized in particular by the configurations of the speed control calculation unit 6, the phase error estimation calculation unit 8, and the frequency / phase estimation calculation unit 9.

[0027] FIG. 2 is a diagram showing a model of a synchronous reluctance motor.

[0028] FIG. 2 shows models corresponding to two selectable d-axis directions in the synchronous reluctance motor 1, with a forward salient pole model on the left in which the d-axis direction is selected in the direction of the maximum inductance value Lmax, and a reverse salient pole model on the right in which the d-axis direction is selected in the direction of the minimum inductance value Lmin.

[0029] The extended induced voltage method used in conventional magnet motors corresponds to a reverse salient pole model because the direction of the magnet magnetic flux is the d-axis, but in a synchronous reluctance motor, the magnitude of each magnetic flux is the magnetic flux generated by the current (= current x inductance), so a forward salient pole model is selected in which the direction with the largest absolute value of magnetic flux is considered to be the main magnetic flux.

[0030] FIG. 3 is a vector diagram of a forward salient pole model.

[0031] In position sensorless control, since the d-q axes, which are the rotor position (magnetic flux phase), cannot be detected, the estimated magnetic flux phase (dc-qc axes) is used as the control phase. In Figure 3, the dc axis of the forward salient pole model is the qc axis of the reverse salient pole model, and the qc axis of the forward salient pole model is in the opposite direction to the dc axis. In other words, if the dc axis and qc axis are swapped and the polarity of the qc axis is determined to be inverted, control is possible in the rotating coordinate system of the forward salient pole model. Here, the deviation in the phase angle between the dc-qc axis and the d-q axis is defined as the phase error Δθ.

[0032] (Speed ​​Control Calculation Unit 6) The speed control calculation unit 6 will be described.

[0033] First, the speed control calculation unit 6 calculates the torque command value τ* according to the following (Equation 2) using proportional control and integral control so that the speed estimate value ωdc follows the speed command value ωr*.

[0034]

[0035] Here, in the above (Equation 2), Ksp represents the proportional gain of the speed control, and Ksi represents the integral gain of the speed control.

[0036] Next, the torque command value τ* and the torque coefficient (= 3 / 2Pm(Ld* - Ld*)iq0*) are used to calculate the d-axis current command value id* according to the following (Equation 3).

[0037]

[0038] Here, in the above (Equation 3), Pm represents the number of pole pairs, Ld represents the d-axis inductance, Lq represents the q-axis inductance, iq0* represents the limit value of the q-axis current command value, and Td represents the torque command filter value.

[0039] The limit value iq0* of the q-axis current command value is changed so as to be approximately inversely proportional to the speed command value ωr* according to the following (Equation 4).

[0040]

[0041] As shown in the above (Equation 4), when the speed command value is low, the limit value iq0* becomes large, and when the speed command value is high, the limit value iq0* becomes small.

[0042] The q-axis current command value iq* is output in accordance with the following (Equation 5) using the above limit value iq0*.

[0043]

[0044] (Phase Error Estimation Calculation Unit 8) The phase error estimation calculation unit 8 will be described.

[0045] The phase error estimation calculation unit 8 uses the d-axis and q-axis voltage command values ​​vdc**, vqc**, the d-axis and q-axis current detection values ​​idc, iqc, and the speed estimation value ωdc to calculate the phase error estimation value Δθc according to the following (Equation 6).

[0046]

[0047] (Frequency / Phase Estimation Calculation Unit 9) The frequency / phase estimation calculation unit 9 will be described.

[0048] The frequency / phase estimation calculation unit 9 calculates the speed estimation value ωdc according to the following (Equation 7) using P (proportional) + I (integral) control so as to make the phase error estimation value Δθc "0" (zero).

[0049]

[0050] Here, in the above (Equation 7), Kp_pll represents the proportional control gain, and Ki_pll represents the integral control gain.

[0051] The proportional control gain Kp_pll is changed in proportion to the speed command value ωr* according to the following (Equation 8).

[0052]

[0053] The integral control gain Ki_pll is changed in proportion to the square of the speed command value ωr* according to the following (Equation 9).

[0054]

[0055] The phase estimate θdc is calculated using the speed estimate ωdc by I (integral) control according to the following equation (10).

[0056]

[0057] (Vector Control Calculation Unit 7) The vector control calculation unit 7 will be described.

[0058] First, the vector control calculation unit 7 uses the electric circuit parameters of the synchronous reluctance motor 1, namely, the winding resistance setting value R*, the d-axis inductance setting value Ld*, the q-axis inductance setting value Lq*, the dc-axis and qc-axis current command values ​​id*, iq*, and the speed estimate value ωdc, to output the dc-axis and qc-axis voltage command values ​​vdc*, vqc* in accordance with the following (Equation 11).

[0059]

[0060] Here, in the above (Equation 11), Tacr represents the response time constant of the current control.

[0061] Secondly, the voltage correction values ​​Δvdc and Δvqc for the dc axis and qc axis are calculated using proportional control and integral control according to the following (Equation 12) so that the current detection values ​​idc and iqc of each component follow the current command values ​​id* and iq* for the dc axis and qc axis.

[0062]

[0063] Here, in the above (Equation 12), Kpd represents the proportional gain of current control on the dc axis, Kid represents the integral gain of current control on the dc axis, Kpq represents the proportional gain of current control on the qc axis, and Kiq represents the integral gain of current control on the qc axis.

[0064] Next, the voltage command values ​​vdc** and vqc** for the dc and qc axes are calculated according to the following (Equation 13).

[0065]

[0066] (Basic Principles of Highly Efficient and Highly Responsive Control) Next, the basic principles of this embodiment that enable the present invention to achieve highly efficient and highly responsive control characteristics will be described.

[0067] 4 to 6 are diagrams showing simulation results when a ramp-signal-like load torque is applied. In FIGS. 4 to 6, a ramp-signal-like load torque is applied at timings (1) to (2) while the speed command value ωr* is kept constant. In FIGS. 4 to 6, the upper rows show speed information (speed command value ωr*, rotational speed ωr) and the proportional control gain Kp_pll of the speed estimation (the integral control gain Ki_pll is omitted here), and the lower rows show current information (detected current values ​​idc and iqc of the d-axis and q-axis). In FIGS. 4 to 6, the initial value iq0* of the q-axis current command value iq* is the "limit value of the q-axis current command value."

[0068] As shown in FIG. 4, when the limit value iq0* of the q-axis current command value is set, it can be seen from the operating waveform that stable operation is possible even when a load torque is applied.

[0069] On the other hand, as shown in FIG. 5, in contrast to the case of FIG. 4, when the limit value iq0* of the q-axis current command value is not changed and the proportional control gain Kp_pll of the speed estimation is changed to a larger proportional control gain Kp1_pll, it can be seen that when a load torque is applied, the rotational speed ωr in the upper stage stalls and the synchronous reluctance motor 1 loses synchronization.

[0070] Therefore, as shown in Figure 6, in contrast to the case of Figure 5, when the proportional control gain Kp1_pll of the speed estimation is not changed and the limit value iq0* of the q-axis current command value is changed to a limit value iq1* that is larger in the "negative" direction, it can be seen that stable operation is possible even when a load torque is applied.

[0071] 4 to 6 show that, for a given rotational speed, stable operation of the synchronous reluctance motor 1 requires increasing the proportional control gain of speed estimation, which also increases the limit value of the q-axis current command value. Here, the case shown in FIG. 4 is a "high-efficiency state" in which the synchronous reluctance motor 1 requires less current, while the case shown in FIG. 6 is a "high-response state" in which the speed estimation gain is large. Furthermore, the case shown in FIG. 5 is an "unstable state" that is intermediate between the high-efficiency state (FIG. 4) and the high-response state (FIG. 6). In this way, by automatically selecting and setting the parameters for the "speed estimation gain" related to high efficiency and high response and the "q-axis current (reactive current) limit value" related to high efficiency in a synchronous reluctance motor of a position sensorless control system, and skillfully controlling the speed estimation gain and the limit value of the q-axis current command value, stable control of the synchronous reluctance motor in a high-efficiency and high-response state can be achieved.

[0072] (Verification Method) Here, a method for verifying whether or not the technology according to this embodiment is adopted will be described.

[0073] FIG. 7 is a diagram showing a typical case where verification is performed on a synchronous reluctance motor.

[0074] 7, first, a voltage detector 21 and a current detector 22 are attached to a power conversion device 20 that drives a synchronous reluctance motor 1. In addition, an encoder 23 is attached to the shaft of the synchronous reluctance motor 1.

[0075] The vector voltage / current component calculation unit 24 calculates vector voltage components (vdcc, vqcc) and vector current components (idcc, iqcc), as well as a speed detection value ωrcc obtained by differentiating the position θ, based on the three-phase AC voltage detection values ​​(vuc, vvc, vwc) and three-phase AC current detection values ​​(iuc, ivc, iwc) output from the voltage detector 21 and the position θ output from the encoder 23.

[0076] The vector current component iqcc is measured at intervals of approximately 10% of the base speed for the speed command value ωr* given to the power conversion device 20. For example, the waveforms of the q-axis current value (iqc) of the vector component are observed when the speed is 10%, 20%, and 30% of the base speed, and if the vector current component iqcc decreases as the speed increases, this means that the limit value of the q-axis current command value is decreasing, and it can be said that there is a high possibility that the technology according to this embodiment is used to control the synchronous reluctance motor 1 being verified.

[0077] Furthermore, the phase error estimate Δθcc is calculated using the vector voltage components vdcc and vqcc, the vector current components idcc and iqcc, and the detected speed value ωrcc according to the following (Equation 14).

[0078]

[0079] For example, when observing the phase error estimate Δθcc at 10%, 20%, and 30% of the base speed, if the phase error estimate Δθcc converges to "0" (zero) more quickly as the speed increases, this means that the gain of the speed estimation is large, and it is highly likely that the technology according to this embodiment is used for the synchronous reluctance motor 1 in question.

[0080] Second Embodiment A second embodiment of the present invention will be described with reference to FIG.

[0081] While the first embodiment employs a method of changing the speed estimation gain and the limit value of the q-axis current command value in accordance with the speed command value, this embodiment employs a method of providing a response frequency setting unit and changing the speed estimation gain and the limit value of the q-axis current command value in accordance with the speed estimation response frequency. Note that in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0082] FIG. 8 is a functional block diagram showing the overall configuration of the motor control system according to this embodiment, together with the motor control device and its related configuration.

[0083] In FIG. 8 , the motor control device has the following functional units: a coordinate conversion unit 5, a speed control calculation unit 6A, a vector control calculation unit 7, a phase error estimation calculation unit 8, a frequency / phase estimation calculation unit 9A, a coordinate conversion unit 10, and a response frequency setting unit 11.

[0084] As in the first embodiment, the speed control calculation unit 6A calculates the torque command value τ* in accordance with the above-mentioned (Equation 2) using proportional control and integral control so that the speed estimate value ωdc follows the speed command value ωr*.

[0085] Further, the torque command value τ* and the torque coefficient (= 3 / 2Pm(Ld* - Ld*)iq1*) are used to calculate the d-axis current command value id* according to the following (Equation 15).

[0086]

[0087] Here, in the above (Equation 15), iq1* represents the limit value of the q-axis current command value.

[0088] The limit value iq1* of the q-axis current command value is changed so as to be proportional to the response frequency Fpll_max according to the following (Equation 16).

[0089]

[0090] The frequency / phase estimation calculation unit 9A calculates the speed estimation value ωdc according to the following (Equation 17) using P (proportional) + I (integral) control so as to set the phase error estimation value Δθc to "0" (zero).

[0091]

[0092] Here, in the above (Equation 17), Kpa_pll represents the proportional control gain, and Kia_pll represents the integral control gain.

[0093] The proportional control gain Kpa_pll is changed in proportion to the response frequency Fpll_max according to the following (Equation 18).

[0094]

[0095] The integral control gain Kia_pll is changed in proportion to the square of the response frequency Fpll_max according to the following (Equation 19).

[0096]

[0097] The response frequency setting unit 11 uses the speed command value ωr* and the electric circuit parameters (Ld*, Lq*) of the synchronous reluctance motor 1 to calculate the response frequency Fpll_max for speed estimation according to the following (Equation 20).

[0098]

[0099] Even if the base frequency of the synchronous reluctance motor 1 is several kHz, the response frequency Fpll_max for speed estimation may be in the range of several tens of Hz to several hundreds of Hz.

[0100] The other configurations are the same as those of the first embodiment.

[0101] The present embodiment configured as described above can also achieve the same effects as those of the first embodiment. That is, in this embodiment, a response frequency setting unit is provided and the speed estimation gain and the limit value of the q-axis current command value are appropriately controlled, thereby realizing highly efficient and highly responsive control of the synchronous reluctance motor.

[0102] Third Embodiment A third embodiment of the present invention will be described with reference to FIGS.

[0103] While the first embodiment employs a method for changing the speed estimation gain and the limit value of the q-axis current command value in accordance with the speed command value, this embodiment employs a method for changing the speed estimation gain and the limit value of the q-axis current command value in accordance with the degree of high efficiency and high response by providing a high efficiency / high response degree setting unit 12. Note that in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0104] FIG. 9 is a functional block diagram showing the overall configuration of the motor control system according to this embodiment, together with the motor control device and its related configuration.

[0105] In FIG. 9 , the motor control device has the following functional units: a coordinate conversion unit 5, a speed control calculation unit 6B, a vector control calculation unit 7, a phase error estimation calculation unit 8, a frequency / phase estimation calculation unit 9B, a coordinate conversion unit 10, and a high-efficiency / high-response degree setting unit 12.

[0106] As in the first embodiment, the speed control calculation unit 6B calculates the torque command value τ* in accordance with the above-mentioned (Equation 2) using proportional control and integral control so that the speed estimate value ωdc follows the speed command value ωr*.

[0107] Further, the torque command value τ* and the torque coefficient (= 3 / 2Pm(Ld* - Ld*)iq2*) are used to calculate the d-axis current command value id* according to the following (Equation 21).

[0108]

[0109] In the above (Equation 21), iq2* represents the limit value of the q-axis current command value. The limit value iq2* of the q-axis current command value is set by the high-efficiency / high-response degree setting unit 12.

[0110] The frequency / phase estimation calculation unit 9B calculates the speed estimation value ωdc according to the following (Equation 22) using P (proportional) + I (integral) control so as to set the phase error estimation value Δθc to "0" (zero).

[0111]

[0112] Here, in the above (Equation 22), Kpb_pll represents a proportional control gain, and Kib_pll represents an integral control gain. The proportional control gain Kpb_pll and the integral control gain Kib_pll are set by the high-efficiency / high-response degree setting unit 12.

[0113] The high efficiency / high response degree setting unit 12 sets the limit value iq2* of the q-axis current command value used in the speed control calculation unit 6B, and the proportional control gain Kpb_pll and integral control gain Kib_pll used in the frequency / phase estimation calculation unit 9B.

[0114] FIG. 10 is a diagram showing the configuration of the high efficiency and high response degree setting unit.

[0115] In FIG. 10 , the high-efficiency / high-response degree setting unit 12 has a table 121 relating to the limit value iq2* of the q-axis current command value and a table 122 relating to the speed estimation gains Kpb_pll and Kib_pll, and sets the limit value iq2* of the current command value and the speed estimation gains Kpb_pll and Kib_pll using these tables.

[0116] Table 121 relating to the limit value iq2* of the q-axis current command value specifies, for example, the relationship between the settings "1" to "8" indicating the degree of high efficiency and high response and the limit value iq2* of the q-axis current command value, with a smaller setting value (i.e., closer to the setting "1") indicating a higher efficiency setting, and a larger setting value (i.e., closer to the setting "8") indicating a higher response setting.

[0117] For example, when setting "1" is selected, the output of limit value iq2* calculated by table 121 becomes limit value iq2*=iq21*. Also, when setting "8" is selected, the output of limit value iq2* calculated by table 121 becomes limit value iq2*=iq28*.

[0118] Table 122 for the speed estimation gains Kpb_pll and Kib_pll specifies, for example, the relationship between the settings "1" to "8" indicating the degree of high response and the speed estimation gains Kpb_pll and Kib_pll, with the larger the setting value (i.e., closer to the setting "8"), the higher the response setting.

[0119] For example, when the setting "8" is selected, the output of the speed estimation gain calculated by the table 121 is proportional control gain Kpb_pll=Kpb8_pll and integral control gain Kib_pll=Kib8_pll.

[0120] The other configurations are the same as those of the first embodiment.

[0121] The present embodiment configured as described above can also achieve the same effects as those of the first embodiment. That is, in this embodiment, a high efficiency / high response degree setting unit is provided, and the degree (numerical value) is selected to control the speed estimation gain and the limit value of the q-axis current command value, thereby achieving high efficiency / high response control of the synchronous reluctance motor.

[0122] In the present embodiment, the cases where the degree of high efficiency and high response is set to "1" to "8" have been described as examples, but the present invention is not limited to this, and a setting less than "1" or a setting greater than "8" may be adopted. Furthermore, the present invention is not limited to eight levels from "1" to "8", and nine or more levels may be adopted.

[0123] <Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to FIGS.

[0124] While the first embodiment employs a method for changing the speed estimation gain and the limit value of the q-axis current command value in accordance with the speed command value, this embodiment employs a method for changing the speed estimation gain and the limit value of the q-axis current command value in accordance with the degree of high efficiency and high response by providing a high efficiency / high response degree setting unit 12A. Note that in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0125] FIG. 11 is a functional block diagram showing the overall configuration of the motor control system according to this embodiment, together with the motor control device and its related configuration.

[0126] In FIG. 11, the motor control device has the following functional units: a coordinate conversion unit 5, a speed control calculation unit 6C, a vector control calculation unit 7, a phase error estimation calculation unit 8, a frequency / phase estimation calculation unit 9C, a coordinate conversion unit 10, and a high-efficiency / high-response degree setting unit 12A.

[0127] As in the first embodiment, the speed control calculation unit 6C calculates the torque command value τ* in accordance with the above-mentioned (Equation 2) using proportional control and integral control so that the speed estimate value ωdc follows the speed command value ωr*.

[0128] Further, the torque command value τ* and the torque coefficient (= 3 / 2Pm(Ld* - Ld*)iq3*) are used to calculate the d-axis current command value id* according to the following (Equation 23).

[0129]

[0130] In the above (Equation 23), iq3* represents the limit value of the q-axis current command value. The limit value iq3* of the q-axis current command value is set by the high-efficiency / high-response degree setting unit 12A.

[0131] The frequency / phase estimation calculation unit 9C calculates the speed estimation value ωdc according to the following (Equation 24) using P (proportional) + I (integral) control so as to set the phase error estimation value Δθc to "0" (zero).

[0132]

[0133] Here, in the above (Equation 24), Kpc_pll represents the proportional control gain, and Kic_pll represents the integral control gain.

[0134] The proportional control gain Kpc_pll is changed in proportion to the response frequency Fpll according to the following (Equation 25).

[0135]

[0136] The integral control gain Kic_pll is changed in proportion to the square of the response frequency Fpll according to the following (Equation 26).

[0137]

[0138] FIG. 12 is a diagram showing the configuration of the high efficiency and high response degree setting unit.

[0139] In FIG. 12, the high efficiency / high response degree setting unit 12A has a table 123 relating to the limit value iq3* of the q-axis current command value and a table 124 relating to the response frequency Fpll, and these tables are used to set the limit value iq3* of the current command value and the response frequency Fpll.

[0140] The table 124 relating to the response frequency Fpll specifies, for example, the relationship between the settings "1" to "8" indicating the degree of high response and the response frequency Fpll, with the larger the setting value (i.e., closer to the setting "8"), the higher the response setting.

[0141] Table 123 relating to the limit value iq3* of the q-axis current command value specifies, for example, the relationship between the settings "1" to "8" indicating the degree of high efficiency and high response and the limit value iq2* of the q-axis current command value, with the smaller the setting value (i.e., closer to the setting "1") indicating a higher efficiency setting, and the larger the setting value (i.e., closer to the setting "8") indicating a higher response setting.

[0142] Here, the limit value iq3* of the q-axis current command value is changed so as to be proportional to the response frequency Fpll according to the following (Equation 27).

[0143]

[0144] That is, the table 124 relating to the response frequency Fpll and the table 123 relating to the limit value iq3* of the q-axis current command value are proportional to each other, and the same setting as that selected in the table 124 is also set in the table 123. For example, when the setting "1" is set in the table 124, the table 123 is also set to "1", the output of the response frequency Fpll calculated by the table 124 is the response frequency Fpll=Fpll1, and the output of the limit value iq3* calculated by the table 123 is the limit value iq3*=iq31*. Also, when the setting "8" is selected, the output of the response frequency Fpll calculated by the table 124 is the response frequency Fpll=Fpll8, and the output of the limit value iq3* calculated by the table 123 is the limit value iq3*=iq38*.

[0145] The other configurations are the same as those of the first embodiment.

[0146] The present embodiment configured as described above can also achieve the same effects as those of the first embodiment. That is, in this embodiment, a high efficiency / high response degree setting unit is provided, and the degree (numerical value) is selected to control the speed estimation gain and the limit value of the q-axis current command value, thereby achieving high efficiency / high response control of the synchronous reluctance motor.

[0147] In the present embodiment, the cases where the degree of high efficiency and high response is set to "1" to "8" have been described as examples, but the present invention is not limited to this, and a setting less than "1" or a setting greater than "8" may be adopted. Furthermore, the present invention is not limited to eight levels from "1" to "8", and nine or more levels may be adopted.

[0148] Fifth Embodiment A fifth embodiment of the present invention will be described with reference to FIG.

[0149] While the first embodiment employs a method of setting the q-axis current limit value and speed estimation gain in the power converter controller (such as a microcomputer), this embodiment employs a method of feeding back the control state variable to a higher-level IOT controller, and resetting the machine-learned q-axis current limit value in the speed control calculation unit and the speed estimation gain in the frequency / phase estimation calculation unit. Note that in this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0150] FIG. 13 is a functional block diagram showing the overall configuration of the motor control system according to this embodiment together with the motor control device and its related configuration.

[0151] In Figure 13, the motor control device has the following functional units: a coordinate conversion unit 5, a speed control calculation unit 6, a vector control calculation unit 7, a phase error estimation calculation unit 8, a frequency / phase estimation calculation unit 9, a coordinate conversion unit 10, and a higher-level IOT controller 13 (machine learning).

[0152] The state quantity of the control is fed back to the IOT controller 13, and machine learning of the limit value of the q-axis current and the speed estimation gain is performed. The limit value of the q-axis current learned by the IOT controller 13 is reset to the speed control calculation unit 6, and the speed estimation gain is reset to the frequency / phase estimation calculation unit 9.

[0153] The other configurations are the same as those of the first embodiment.

[0154] The present embodiment configured as described above can also achieve the same effects as those of the first embodiment. Furthermore, in this embodiment, a higher-level IOT controller is employed, so that the speed estimation gain and the limit value of the q-axis current command value can be well controlled without adjustment, and highly efficient and highly responsive control of the synchronous reluctance motor can be achieved.

[0155] In this embodiment, an example has been described in which a higher-level IOT controller is adopted for the first embodiment, but this is not limited to this. For example, a higher-level IOT controller may be adopted for the second to fourth embodiments, as in the first embodiment.

[0156] Sixth Embodiment A sixth embodiment of the present invention will be described with reference to FIG.

[0157] This embodiment shows a case where the motor control system of the third embodiment is applied to a drive system for a synchronous reluctance motor. In this embodiment, the same members as those in the third embodiment are designated by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0158] FIG. 14 shows a schematic diagram of the overall configuration of a drive system for a synchronous reluctance motor according to this embodiment.

[0159] 14, a synchronous reluctance motor 1 is driven by a power conversion device 20. In the power conversion device 20, the functional units of the power converter 2, DC power supply 3, and current detector 4 are implemented as hardware, and the functional units of the coordinate conversion unit 5, speed control calculation unit 6A, vector control calculation unit 7, phase error estimation calculation unit 8, frequency / phase estimation calculation unit 9A, and response frequency setting unit 11 are implemented as software 20a.

[0160] In addition, higher-level devices such as a digital operator 20b, a personal computer 27, a tablet 28, and a smartphone 29 are provided, which can be used to set and change the degree of high efficiency and high response of the software 20a from "1" to "n" (n: positive integer).

[0161] The other configurations are the same as those of the third embodiment.

[0162] The present embodiment configured as above can also achieve the same effects as the third embodiment.

[0163] In this embodiment, the case where the motor control system of the first embodiment is applied has been described as an example, but this is not limited to this, and for example, the motor control systems of the fourth and fifth embodiments may also be applied.

[0164] <Notes> The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and also includes those in which some of the configurations are omitted.

[0165] For example, if this embodiment is applied to a fan pump or compressor system driven by a synchronous reluctance motor, highly efficient and highly responsive control characteristics can be achieved even in position sensorless vector control.

[0166] The degree of high efficiency and high response may be set on a field bus such as a programmable logic controller, a local area network connected to a computer, or an IOT controller.

[0167] Furthermore, in the first to sixth embodiments, as shown in the above (Equation 13), voltage correction values ​​Δvdc, Δvqc are created from the current command values ​​id*, iq* and the current detection values ​​idc, iqc, and a calculation is performed in which this voltage correction value is added to the voltage command value for vector control. However, the present invention is not limited to this, and intermediate current command values ​​id**, iq** to be used in the vector control calculation may be created from the current command values ​​id*, iq* and the current detection values ​​idc, iqc according to the following (Equation 28), and vector control calculation may be performed according to the following (Equation 29) using the speed estimate value ωdc and the electric circuit parameters of the synchronous reluctance motor 1.

[0168]

[0169]

[0170] In the above formula (28), Kpd1 represents the proportional gain of the dc-axis current control, Kid1 represents the integral gain of the dc-axis current control, Kpq1 represents the proportional gain of the qc-axis current control, and Kiq1 represents the integral gain of the qc-axis current control. Also, in the above formula (29), Td represents the electrical time constant (Ld / R) of the d-axis, and Tq represents the electrical time constant (Lq / R) of the q-axis.

[0171] Alternatively, the voltage correction value Δvd_p* of the proportional calculation component of the dc axis, the voltage correction value Δvd_i* of the integral calculation component of the dc axis, the voltage correction value Δvq_p* of the proportional calculation component of the qc axis, and the voltage correction value Δvq_i* of the integral calculation component of the qc axis, which are used for vector control calculation, may be created according to the following (Equation 30) from the current command values ​​id*, iq* and the detected current values ​​idc, iqc, and the vector control calculation shown in the following (Equation 31) may be performed using the estimated speed value ωdc and the electrical circuit parameters of the synchronous reluctance motor 1.

[0172]

[0173]

[0174] Here, in the above (Equation 30), Kpd2 represents the proportional gain of current control on the dc axis, Kid2 represents the integral gain of current control on the dc axis, Kpq2 represents the proportional gain of current control on the qc axis, and Kiq2 represents the integral gain of current control on the v axis.

[0175] In addition, a vector control calculation shown in the following (Equation 32) may be performed using the first-order lag signal iqctd of the dc-axis current command value id* and the qc-axis current detection value iqc, the speed estimation value ωdc, and the electrical circuit parameters of the synchronous reluctance motor 1.

[0176]

[0177] In the first to sixth embodiments, the switching elements constituting the power converter 2 may be Si (silicon) semiconductor elements or wide bandgap semiconductor elements such as SiC (silicon carbide) and GaN (gallium nitride).

[0178] Furthermore, the first to eighth embodiments are merely examples for explaining the present invention, and appropriate omissions and simplifications have been made to clarify the explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0179] Examples of various types of information may be described using expressions such as "table," "list," and "queue," but the various types of information may also be expressed using data structures other than these. For example, various types of information such as "XX table," "XX list," and "XX queue" may also be expressed as "XX information." When describing identification information, expressions such as "identification information," "identifier," "name," "ID," and "number" are used, but these are interchangeable. When there are multiple components having the same or similar functions, they may be described using the same reference numeral with different subscripts. Furthermore, when there is no need to distinguish between these multiple components, the subscripts may be omitted.

[0180] In each embodiment, processing performed by executing a program may be described. Here, a computer executes the program using a processor (e.g., a CPU or a GPU) and performs processing defined by the program using storage resources (e.g., memory) and interface devices (e.g., communication ports). Therefore, the entity performing the processing by executing the program may be the processor. Similarly, the entity performing the processing by executing the program may be a controller, device, system, computer, or node having a processor. The entity performing the processing by executing the program may be any computing unit, and may include a dedicated circuit that performs specific processing. Here, the dedicated circuit may be, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a CPLD (Complex Programmable Logic Device).

[0181] A program may be installed on a computer from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server may include a processor and storage resources for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. In addition, in each embodiment, two or more programs may be realized as one program, or one program may be realized as two or more programs.

[0182] 1...Synchronous reluctance motor, 2...Power converter, 3...DC power supply, 4...Current detector, 5...Coordinate conversion unit, 6, 6A, 6B, 6C...Speed ​​control calculation unit, 7...Vector control calculation unit, 8...Phase error estimation calculation unit, 9, 9A, 9B, 9C...Frequency / phase estimation calculation unit, 10...Coordinate conversion unit, 11...Response frequency setting unit, 12, 12A...High efficiency / high response degree setting unit, 13...IOT controller, 20...Power conversion device, 20a...Software, 20b...Digital operator, 21...Voltage detector, 22...Current detector, 23...Encoder, 24...Vector voltage / current component calculation unit, 27...Personal computer, 28...Tablet, 29...Smartphone, 121, 122, 123, 124...Table

Claims

1. A motor control device that performs position sensorless vector control using a forward salient pole model of a synchronous reluctance motor, comprising: a speed control calculation unit that calculates a current command value based on the difference between a speed command value and a speed estimate value, the speed estimate value, and a limit value; a vector control calculation unit that calculates a voltage command value based on a current detection value, the current command value, and the speed estimate value; a phase error estimation calculation unit that calculates a phase error estimate based on the voltage command value, the speed estimate value, and the current detection value; and a frequency / phase estimation calculation unit that calculates a speed estimate and a phase estimate based on the phase error estimate and the speed command value, wherein the speed control calculation unit uses the limit value of the q-axis current command value that is changed in accordance with a proportional gain of the speed estimation.

2. A motor control device according to claim 1, characterized in that at least one of a speed estimation gain and a limit value of a q-axis current is calculated and changed in accordance with a speed command value or a speed estimation value while the synchronous reluctance motor is in operation.

3. A motor control device according to claim 1, characterized in that the response frequency of the speed estimation is changed in accordance with the speed command value or the estimated speed value, and the speed estimation gain is changed using the changed response frequency of the speed estimation, or the limit value of the q-axis current is changed in accordance with the response frequency of the speed estimation.

4. A motor control device according to claim 1, characterized in that during operation of the synchronous reluctance motor, at least one of a speed estimation gain and a q-axis current limit value is calculated and changed in accordance with a parameter that changes the degree of high efficiency and high response.

5. A motor control device according to claim 1, characterized in that the response frequency of speed estimation is changed in accordance with a parameter that changes the degree of high efficiency and high response, and the speed estimation gain is changed using the changed response frequency of speed estimation, or the limit value of the q-axis current is changed in accordance with the response frequency of speed estimation.

6. A motor control device according to claim 2 or 3, characterized in that the speed estimation gain or the response frequency of the speed estimation is changed so as to be proportional to the speed command value or the speed estimation value, and the q-axis current limit value is changed so as to be inversely proportional to the speed command value or the speed estimation value.

7. A motor control device according to claim 4 or 5, characterized in that the speed estimation gain or the response frequency of the speed estimation is changed in proportion to a parameter that changes the degree of high efficiency and high response, and the limit value of the q-axis current is changed in inverse proportion to the parameter.

8. A motor control device according to claim 3 or 5, wherein the maximum value of the response frequency of the speed estimation is determined using the inductance values ​​of the d-axis and q-axis and the speed command value or the speed estimation value.

9. A motor control device according to claim 4 or 5, wherein the degree of high efficiency and high response set by the user is obtained by dividing the ratio of high efficiency to high response into n values ​​ranging from 1, which indicates emphasis on high efficiency, to n, where n is a positive integer, which indicates emphasis on high response, and wherein any of the n values ​​can be freely set or changed using a microcomputer, a personal computer, a tablet, or an IoT device.

10. A motor control device according to claim 9, wherein the value corresponding to the numerical value n is a speed estimation gain or a speed estimation response frequency that is changed in proportion to a parameter that changes the degree of high efficiency and high response, or a limit value of the q-axis current that is changed in inverse proportion to the parameter.

11. A motor control device according to claim 8, characterized in that the voltage command value, current detection value, phase error and speed estimates are fed back to an IOT controller, which is a higher-level device, for analysis, and parameters relating to the response frequency of the speed estimate are automatically corrected.

12. A motor control system comprising: a synchronous reluctance motor; a power converter that supplies AC current to said synchronous reluctance motor based on a voltage command; and the motor control device according to claim 1 that controls the synchronous reluctance motor by outputting a voltage command value calculated based on a speed command value to said power converter.

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