JP6179389B2 - Electric motor control device - Google Patents

Description

  The present invention relates to a control device for an electric motor including a permanent magnet, and more particularly to a technique for estimating a permanent magnet temperature and a winding temperature with high accuracy.

  As a technique for estimating the temperature of the permanent magnet mounted on the electric motor and the winding temperature, for example, one disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2008-43128) is known. In Patent Document 1, the inductance of the armature is measured, and the winding resistance or the winding temperature is estimated using the measured inductance. Then, the magnetic flux density or temperature of the permanent magnet is estimated by a circuit equation using the above inductance and winding resistance. At this time, the inductance of the armature obtained from the current condition is used to estimate the winding resistance or winding temperature and the magnetic flux or temperature of the magnet.

  However, the inductance of the armature changes depending on the amount of magnetic flux, not the current, and is therefore affected by the magnetic flux. Therefore, the inductance obtained only by the current value is not an accurate numerical value, and if the magnet temperature is estimated using this inaccurate inductance, there arises a problem that the estimation accuracy of the magnet temperature is lowered.

JP 2008-43128 A

  As described above, the conventional motor control device employs a method of estimating the magnet temperature and the winding temperature using the armature inductance, and thus there is a problem that high-precision estimation cannot be performed.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an electric motor capable of accurately estimating a permanent magnet temperature and a winding temperature provided in the electric motor. It is to provide a control device.

  In order to achieve the above object, the present invention provides a correlation data storage for storing correlation data in which a voltage amplitude or a voltage phase of a high frequency component is associated with each β angle, which is a phase of a current with respect to an induced voltage, and each temperature of a permanent magnet. And a magnet temperature estimator for estimating the temperature of the permanent magnet with reference to the correlation data based on the fundamental wave detected by the fundamental wave detector and the high frequency component detected by the high frequency component detector. Further, the magnetic flux of the permanent magnet is calculated based on the temperature of the permanent magnet, and the magnetic flux calculation unit that calculates the motor magnetic flux based on the magnetic flux of the permanent magnet; the motor magnetic flux calculated by the magnetic flux calculation unit; A winding estimation unit that estimates the winding resistance or winding temperature of the armature coil based on the wave and the high frequency component is provided. The winding estimation unit estimates the winding resistance or the winding temperature of the armature coil using a frequency component that is the same as or lower than the frequency of the high-frequency component used in the magnet temperature estimation unit.

  In the motor control device according to the present invention, the winding estimation unit estimates the winding resistance or winding temperature of the armature coil using the same or lower frequency component as the harmonic component used in the magnet temperature estimation unit. Both the permanent magnet temperature provided in the electric motor and the winding temperature can be estimated with high accuracy.

It is a circuit diagram which shows the structure of the control apparatus of the electric motor which concerns on embodiment of this invention. It is a block diagram which shows the detailed structure of the control part of the control apparatus of the electric motor which concerns on 1st Embodiment of this invention, and a temperature estimator. It is explanatory drawing which shows correlation data of the control apparatus of the electric motor which concerns on 1st Embodiment of this invention. It is a characteristic view which shows the voltage amplitude of a fundamental wave and a harmonic of the control apparatus of the electric motor which concerns on 1st Embodiment of this invention. It is a characteristic view which shows the voltage amplitude of a fundamental wave and a harmonic of the control apparatus of the electric motor which concerns on 1st Embodiment of this invention. It is a block diagram which shows the detailed structure of the control part and temperature estimator of the control apparatus of the electric motor which concerns on the modification of 1st Embodiment of this invention. It is a block diagram which shows the detailed structure of the control part and temperature estimator of the control apparatus of the electric motor which concerns on 2nd Embodiment of this invention. It is explanatory drawing which shows correlation data of the control apparatus of the electric motor which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the detailed structure of the control part and temperature estimator of the control apparatus of the electric motor which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the detailed structure of the control part of the control apparatus of the electric motor which concerns on 4th Embodiment of this invention, and a temperature estimator. It is a flowchart which shows the process sequence of the control apparatus of the electric motor which concerns on 4th Embodiment of this invention. It is a flowchart which shows the process sequence of the control apparatus of the electric motor which concerns on the modification of 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of an electric motor control device 101 according to an embodiment of the present invention and a permanent magnet type electric motor 13 (hereinafter referred to as “motor 13”) controlled by the control device 101. As shown in FIG. 1, the control device 101 includes a DC power supply 11 that outputs a DC voltage, a capacitor 14, and a plurality of semiconductor switches, and an inverter that generates an AC voltage by switching each semiconductor switch on and off. And a circuit 12. Further, the controller 15 for controlling on / off of each semiconductor switch mounted on the inverter circuit 12 and the temperature of the permanent magnet mounted on the motor 13 and the winding temperature of the armature coil are estimated by a method described later. And a temperature estimator 16. The drive of the motor 13 is controlled by supplying the AC voltage output from the inverter circuit 12 to the motor 13.

  The control unit 15 and the temperature estimator 16 can be configured as an integrated computer including a central processing unit (CPU) and storage means such as a RAM, a ROM, and a hard disk, for example. Moreover, in each embodiment shown below, the control part 15 and the temperature estimator 16 are attached | subjected and described. For example, in the first embodiment, “control unit 15-1” and “temperature estimator 16-1” are shown.

  The motor 13 is an m-phase (for example, three-phase, five-phase, etc.) motor that is different in phase and connected at a neutral point. The motor 13 is provided with a permanent magnet, and an armature coil is wound around the stator. It has a structure. The rotor is rotationally driven by passing an alternating current through the armature coil.

[Description of First Embodiment]
FIG. 2A is a block diagram showing the configuration of the control unit 15-1 according to the first embodiment of the present invention, and FIG. 2B shows the configuration of the temperature estimator 16-1 according to the first embodiment. FIG.

  As shown in FIG. 2A, the control unit 15-1 determines whether the d-axis, q-axis current command value idq_ref is different from the d-axis, q-axis current feedback value idq, A dq current controller 21 for calculating the q-axis voltage is provided. Further, a non-interference control unit 22 for obtaining a correction value of a voltage command value that removes interference between the d-axis and the q-axis from the d-axis current command value and the q-axis current command value, and this correction value is output from the dq current control unit 21. And an adder 29 for calculating the d-axis and q-axis voltage command values vdq in addition to the command values to be corrected, and coordinate conversion for converting the corrected d-axis and q-axis voltages vdq into m-phase voltage commands vmp Part 23.

  Furthermore, the modulation factor calculation unit 24 that calculates the modulation factor of each phase based on the m-phase voltage command vmp, and the on / off control of the semiconductor switch based on the voltage command value for each phase, and the DC power source 11 And an inverter circuit 12 that converts a supplied DC voltage into an AC voltage. The motor 13 can be driven by supplying the AC voltage output from the inverter circuit 12 to the motor 13.

  Further, a current sensor 25 for measuring a current flowing through the motor 13 is provided on the input side of the motor 13, and the current imp of each phase detected by the current sensor 25 is detected by a plurality of frequency components. Supplied to the unit 26.

  The multiple frequency component detection unit 26 analyzes the frequency component included in the current that is passed through the motor 13 and detects the fundamental wave and the higher-frequency component having a higher frequency than the fundamental wave. Therefore, the fundamental wave current idq and the k-order harmonic voltage vdq_k (k = 2, 3,...) And the k-order harmonic current idq_k (k = 2, 3,...) Are detected. And this detected value is output to the magnet temperature estimation part 31 shown in FIG.2 (b). That is, the multiple frequency component detection unit 26 has a function as a fundamental wave detection unit that detects a fundamental wave that is a drive frequency of the motor 13 (electric motor). The multiple frequency component detection unit 26 has a function as a high frequency component detection unit that detects a frequency component higher than the fundamental wave.

  In addition, a coordinate conversion unit 27 that converts the m-phase fundamental current detected by the current sensor 25 into a dq-axis current based on the rotation angle θe of the motor 13 is provided. The dq axis current idq output from the coordinate conversion unit 27 is output to the subtractor 28 as the feedback value described above.

  On the other hand, as shown in FIG. 2B, the temperature estimator 16-1 includes a magnet temperature estimation unit 31 that estimates the temperature Tm of the permanent magnet provided in the rotor of the motor 13, and a magnet that calculates the magnet magnetic flux Φa_Tm at the temperature Tm. A magnetic flux calculation unit 32 and a motor magnetic flux calculation unit 33 for calculating a motor magnetic flux Φmtr (electric motor magnetic flux) generated in the motor are provided. That is, the magnet magnetic flux calculation unit 32 and the motor magnetic flux calculation unit 33 calculate the magnetic flux of the permanent magnet based on the temperature of the permanent magnet, and further calculate the motor magnetic flux Φmtr based on the magnetic flux of the permanent magnet. It has a function as a calculation unit.

  Further, the temperature estimator 16-1 includes a correlation data storage unit 36. Further, the temperature estimator 16-1 includes a winding resistance calculation unit 34 that calculates the winding resistance of the armature coil wound around the stator, and a winding temperature estimation unit 35 that estimates the temperature of the winding. I have. That is, the winding resistance calculation unit 34 and the winding temperature estimation unit 35 are based on the motor magnetic flux Φmtr calculated by the magnetic flux calculation unit (the magnet magnetic flux calculation unit 32 and the motor magnetic flux calculation unit 33), the fundamental wave, and the harmonics. A function as a winding estimation unit for estimating the winding resistance or winding temperature of the armature coil is provided.

  The correlation data storage unit 36 stores data in which a relationship in which the β angle of the fundamental wave is associated with the voltage amplitude of each order is determined for each of a plurality of permanent magnet temperatures. Specifically, as shown in FIG. 3, for each order, a characteristic diagram showing the voltage amplitude when the horizontal axis is β angle (current phase with respect to no-load induced voltage) is stored. Details will be described later.

  The magnet temperature estimation unit 31 refers to the data stored in the correlation data storage unit 36 described above based on the current idq output from the coordinate conversion unit 27 shown in FIG. 2A and each harmonic voltage vdq_k. Thus, the temperature Tm of the permanent magnet provided in the rotor of the motor 13 is estimated. A detailed method for estimating the permanent magnet temperature will be described later.

  The magnet flux calculator 32 obtains the magnet flux Φa_Tm at the temperature Tm based on the temperature Tm of the permanent magnet estimated by the magnet temperature estimator 31. Since the temperature Tm of the permanent magnet and the magnet flux Φa uniquely correspond to each other, the magnet flux Φa can be determined based on the temperature Tm. The motor magnetic flux calculator 33 obtains the motor magnetic flux Φmtr generated in the motor 13 based on the magnetic flux generated by the magnet magnetic flux Φa and the fundamental wave current idq.

  The winding resistance calculation unit 34 outputs the voltage command value vdq input to the coordinate conversion unit 23 shown in FIG. 2A, the motor magnetic flux Φmtr output from the motor magnetic flux calculation unit 33, and the magnet temperature estimation unit 31. The winding resistance is calculated by receiving the input current idq, k-order harmonic voltage vdq_k, and k-order harmonic current idq_k. A detailed calculation method will be described later. At this time, the high frequency component used for the calculation of the winding resistance is a component lower than the high frequency component used for estimating the magnet temperature, that is, the same or lower frequency component than the harmonic current idq_k.

  Then, by estimating the temperature Tm of the permanent magnet, the state of the permanent magnet can be recognized, which can be used for improving the controllability capability of the motor 13 and protecting against demagnetization. On the other hand, overcurrent control is possible by estimating the winding temperature of the stator. That is, when the estimated temperature of the winding reaches a preset threshold temperature, it is possible to perform control such as reducing the output of the motor 13 or stopping the motor 13.

  Next, the operation of the motor control device 101 according to this embodiment configured as described above will be described.

  When driving of the motor 13 is started, the current command value idq_ref shown in FIG. 2A is supplied, and the deviation from the current feedback value idq is obtained by the subtractor 28. The deviation (idq_ref−idq) is supplied to the dq current control unit 21. The dq current control unit 21 calculates the d-axis and q-axis voltage command values, and the voltage command value is added to the correction value output from the non-interference control unit 22 to obtain the voltage command value vdq.

  The voltage command value vdq is converted into an m-phase (for example, three-phase, five-phase) voltage command value vmp by the coordinate conversion unit 23, and the modulation rate calculation unit 24 converts the voltage command value vmp into a modulation rate. It is calculated and supplied to the inverter circuit 12. The inverter circuit 12 converts the DC voltage supplied from the DC power supply 11 into an m-phase AC voltage by controlling on and off of a plurality of switching elements (see FIG. 1) based on the voltage command value vmp. Then, by supplying this AC voltage to the motor 13, the motor 13 can be driven to rotate.

  Further, the currents imp (m in total) supplied to the motor 13 are detected by the current sensor 25 and supplied to the multiple frequency component detection unit 26. The multiple frequency component detection unit 26, based on the current imp and the voltage command value vmp, a voltage vdq_k that is a k-order harmonic of the voltage supplied to the motor 13 and a k-th order of the current supplied to the motor 13. The current idq_k, which is a higher harmonic wave, is obtained. Further, the current imp is output to the coordinate conversion unit 27. The coordinate conversion unit 27 converts the m-phase current imp into a d-axis and q-axis current idq, and outputs this to the subtractor 28 as a feedback value. In this way, the motor 13 can be stably driven and controlled.

  On the other hand, the voltage vdq_k and current idq_k output from the multiple frequency component detector 26, the current idq output from the coordinate converter 27, and the voltage command value vdq output from the adder 29 are shown in FIG. Is supplied to the temperature estimator 16-1.

  The magnet temperature estimator 31 of the temperature estimator 16-1 receives the fundamental wave current idq, the kth harmonic voltage vdq_k, and the kth harmonic current idq_k, and receives the temperature of the permanent magnet provided in the rotor of the motor 13. Is estimated. Hereinafter, a temperature estimation method will be described.

  The correlation data storage unit 36 shown in FIG. 2B stores a map indicating the amplitude and temperature characteristics of at least one order harmonic voltage with respect to the β angle of the fundamental wave. Specifically, as shown in FIGS. 3 (a) and 3 (b), with respect to the harmonics of the respective orders, the horizontal axis represents the β angle and the vertical axis represents the voltage amplitude. Data is stored as a map. In addition, in FIG. 3, the voltage of a p-order harmonic (FIG. 3 (a)) and the voltage of a q-order harmonic (FIG. 3 (b)) are shown as an example, and the permanent magnet temperature is 60 ° C. The case of three temperatures of 140 ° C. and 220 ° C. is shown (shown by three bar graphs). In the figure, for simplicity of explanation, only three temperatures of 60 ° C., 140 ° C., and 220 ° C. are shown, but actually the temperature is set in increments of 10 ° C., for example. Referring to FIG. 3, for example, FIG. 3A shows that “when the β angle of the fundamental wave is 90 degrees and the magnet temperature is 220 ° C., the voltage amplitude is P1”.

  In the present embodiment, as described above, the k-th harmonic voltage vdq_k (k = 2, 3, 3) output from the multiple frequency component detection unit 26 illustrated in FIG. ..) and k-th harmonic current idq_k (k = 2, 3,...) Are supplied. Furthermore, a current idq is supplied. Then, by applying these numerical values to the map stored in the correlation data storage unit 36, the temperature of the permanent magnet is estimated.

  Specifically, a β angle that is an angle formed by the d-axis current id and the q-axis current iq can be obtained based on the fundamental wave current idq. Furthermore, a voltage generated in the winding can be obtained based on the harmonic voltage vdq_k and the frequency of the harmonic. Then, by applying this voltage to the map shown in FIG. 3, the magnet temperature can be estimated. For example, when the β angle is 90 deg and the voltage is P1, it corresponds to 220 ° C. among the three bar graphs shown in FIG. 3A, so that the temperature Tm of the permanent magnet can be estimated to be 220 ° C. In addition, as shown in FIGS. 3A and 3B, the temperature can be estimated with higher reliability by estimating the temperature using two harmonics.

  Next, the magnet flux calculator 32 shown in FIG. 2B calculates the magnet flux Φa_Tm based on the permanent magnet temperature Tm output from the magnet temperature estimator 31. The magnet magnetic flux Φa_Tm changes depending on the temperature Tm of the permanent magnet. Specifically, a reference temperature and magnetic flux are set, and an arithmetic expression indicating the amount of change in magnetic flux per unit temperature change is set. Therefore, the magnet magnetic flux Φa_Tm can be obtained by using this arithmetic expression. The magnet magnetic flux Φa_Tm is supplied to the motor magnetic flux calculator 33.

  The motor magnetic flux calculator 33 calculates the motor magnetic flux Φmtr based on the magnet magnetic flux Φa_Tm and the fundamental wave current idq. Then, the calculated motor magnetic flux Φmtr is output to the winding resistance calculation unit 34.

  The winding resistance calculator 34 receives the currents idq, Φmtr, vdq_k, idq_k, and vdq, and obtains the winding resistance R (tr). “Tr” is the winding temperature. The winding resistance R (tr) can be obtained by the following equation (1) as is well known.

R (tr) = {vq−ω (Φa (tm) + Ld (Φmtr) · id)} / iq (1)
In the above equation (1), vq is the q-axis voltage of the fundamental wave voltage Vdq, ω is the electrical angular frequency, Φa (tm) is the magnet magnetic flux at the magnet temperature tm, and Ld (Φmtr) is the motor magnetic flux of Φmtr. D-axis inductance, id is a d-axis current, and iq is a q-axis current. As shown in the equation (1), in calculating the winding resistance R, a frequency component lower than the harmonic of the order used for the temperature estimation of the permanent magnet in the magnet temperature estimation unit 31, that is, the current and voltage of the fundamental wave are calculated. Used.

  Then, by calculating the above equation (1), the winding resistance Ra_Tr at the temperature Tr can be obtained, and the data of the winding resistance Ra_Tr is output to the winding temperature estimation unit 35. In Equation (1), the winding resistance R (tr) is calculated using the fundamental waves vq, id, and iq, but k-order harmonics vq_k, id_k, and iq_k can also be used. However, the harmonic order k is the same as or lower than the order used in estimating the magnet temperature. Further, the winding resistance R (tr) at the winding temperature tr may be obtained using the following equation (2).

R (tr) = (vq + ω · Lq (Φmtr) · iq) / id (2)
The winding temperature estimation unit 35 calculates the winding temperature Tr based on the winding resistance Ra_Tr calculated by the winding resistance calculation unit 34. Then, the permanent magnet temperature Tm estimated by the magnet temperature estimation unit 31 and the winding temperature Tr estimated by the winding temperature estimation unit 35 are output to a controller (not shown) provided in the subsequent stage.

  With this controller, it is possible to perform control to stably drive the motor based on the temperature Tm of the permanent magnet, and it is possible to perform overheat prevention control of the stator winding based on the winding temperature Tr It becomes.

  Thus, in the motor control apparatus 101 according to the first embodiment, the temperature Tm of the permanent magnet is estimated using the current supplied to the motor 13, the fundamental wave of the voltage, and the harmonics. The temperature Tm of the permanent magnet can be acquired without providing a temperature sensor or the like. Therefore, the demagnetization state of the permanent magnet can be recognized, and the motor 13 can be controlled with high accuracy. Moreover, since winding resistance Ra_Tr of an armature coil is calculated | required based on temperature Tm of a permanent magnet and by extension, winding temperature Tr is calculated | required, it can prevent that a winding overheats.

  Furthermore, in the present embodiment, when calculating the winding temperature Tr, the calculation is performed using the same or lower frequency component as the harmonic used for estimating the temperature Tm of the permanent magnet. That is, the lower the frequency, the greater the proportion of the voltage generated by the winding resistance Ra_Tr with respect to all the voltages. On the contrary, the higher the frequency, the larger the ratio of the voltage due to the coil magnetic flux to all the voltages. Therefore, the estimation accuracy of the temperature Tm can be improved by increasing the order of the harmonics used when estimating the temperature Tm of the permanent magnet. Furthermore, by reducing the frequency used for the calculation of the winding resistance Ra_Tr, the estimation accuracy of the winding resistance Ra_Tr can be improved, and as a result, the estimation accuracy of the winding temperature Tr can be improved.

  In addition, as an example, the order of the harmonics used when estimating the temperature Tm of the permanent magnet is, as shown in FIGS. 4A and 4B, the order in which the amplitude has the maximum among the harmonics. Can be used. That is, when the motor 13 is a three-phase motor, the third harmonic is almost zero and the voltage amplitude of the fifth harmonic is the maximum, as shown in FIG. Adopt waves. Also, as shown in FIG. 4B, in the case of a five-phase motor, the fifth harmonic is almost zero, so the third harmonic having the maximum amplitude is adopted. By doing so, since the temperature Tm of the permanent magnet is estimated using a harmonic voltage having a large amplitude, the temperature of the permanent magnet can be estimated with higher accuracy. In addition, the temperature of the winding can be estimated with higher accuracy.

  As another example of how to determine the harmonic order, as shown in FIGS. 5A and 5B, a voltage of the minimum order excluding the order of the phase number of the harmonics can be used. That is, when the motor 13 is a three-phase motor, the voltage amplitude of the fifth harmonic is the minimum order as shown in FIG. In this case, the third harmonic is employed because the third harmonic is the minimum order as shown in FIG. By doing so, since the magnet temperature is estimated using the voltage of the harmonic of the lowest order, the calculation load due to handling a high frequency can be reduced.

[Description of Modified Example of First Embodiment]
Next, a modification of the first embodiment described above will be described. FIGS. 6A and 6B are block diagrams illustrating the configuration of the motor control device according to the modification of the first embodiment. In this modification, the motor 13 is controlled based on the command value of the current imp of each phase, in contrast to the first embodiment (FIG. 2) described above. Other than that, the configuration is the same as in the first embodiment. In other words, in FIG. 2, the coordinate conversion unit 23 that converts the two phases of the dq axis into the m phase and the coordinate conversion unit 27 that converts the m phase into the two phases of the dq axis are provided. It differs in that these are not provided. Other configurations are the same as those in the first embodiment.

  With such a configuration, the temperature Tm of the permanent magnet and the winding temperature Tr can be estimated with high accuracy similarly to the first embodiment even when the control is performed in the m phase.

[Description of Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 7A is a block diagram showing a configuration of the control unit 15-2 used in the motor control apparatus according to the second embodiment of the present invention, and FIG. 7B is a temperature estimation according to the second embodiment. It is a block diagram which shows the structure of the device 16-2.

  As shown in FIG. 7A, the control unit 15-2 determines whether the d-axis, q-axis current command value idq_ref is different from the d-axis, q-axis current feedback value idq, A dq current controller 21 for calculating the q-axis voltage is provided. Further, a non-interference control unit 22 for obtaining a correction value of a voltage command value that removes interference between the d-axis and the q-axis from the d-axis current command value and the q-axis current command value, and this correction value is output from the dq current control unit 21. And an adder 29 for calculating the d-axis and q-axis voltage command values vdq, and a coordinate conversion for converting the corrected d-axis and q-axis voltages vdq into an m-phase voltage command vmp_base. Part 23.

  Further, the control unit 15-2 determines the harmonic d based on the deviation between the harmonic current command value idq_n_ref of the d-axis and the q-axis and the feedback value idq_n of the harmonic d-axis and the q-axis current. A dq_n current control unit 43 that calculates an axis and q-axis voltage, and a coordinate conversion unit 44 that converts a harmonic d-axis and q-axis voltage vdq_n into an m-phase voltage command vmp_n. Also, an adder 41 that calculates the m-phase voltage command value vmp by adding the fundamental voltage command vmp_base output from the coordinate conversion unit 23 and the harmonic voltage command vmp_n output from the coordinate conversion unit 44. And a modulation factor calculation unit 24 that calculates the modulation factor of each phase based on the m-phase voltage command vmp, and the on / off control of the semiconductor switch based on the voltage command for each phase. And an inverter circuit 12 that converts a supplied DC voltage into an AC voltage. The motor 13 can be driven by supplying the AC voltage output from the inverter circuit 12 to the motor 13.

  Further, a current sensor 25 for measuring a current flowing through the motor 13 is provided on the input side of the motor 13, and the fundamental wave of the current imp of each phase detected by the current sensor 25 is expressed in coordinates. The harmonics are supplied to the conversion unit 27 and the harmonics are supplied to the coordinate conversion unit 42.

  The coordinate conversion unit 27 performs coordinate conversion of the fundamental wave of the current imp based on the rotation angle θe of the motor 13, and calculates the d-axis and q-axis current idq. This current idq is output to the subtractor 28 as a feedback value. The coordinate conversion unit 42 performs coordinate conversion of the harmonics of the current imp based on the rotation angle θe of the motor 13 and calculates the d-axis and q-axis currents idq_n. This current idq_n is output to the subtracter 45 as a feedback value. The current idq output from the coordinate conversion unit 27, the current idq_n output from the coordinate conversion unit 42, and the voltage command Vmp_n output from the dq_n current control unit 43 are the magnet temperature estimation unit illustrated in FIG. 31 is output.

  On the other hand, as shown in FIG. 7B, the temperature estimator 16-2 includes a magnet temperature estimation unit 31 for estimating the temperature Tm of the permanent magnet provided in the rotor of the motor 13, and a magnet for obtaining the magnet magnetic flux Φa_Tm at the temperature Tm. A magnetic flux calculation unit 32; a motor magnetic flux calculation unit 33 for calculating a motor magnetic flux Φmtr generated in the motor; a winding resistance calculation unit 34 for calculating a winding resistance of an armature coil wound around the stator; A winding temperature estimation unit 35 for estimating the temperature is provided. Further, a correlation data storage unit 36 is provided.

  The correlation data storage unit 36 stores the relationship between the β angle of the fundamental wave and the voltage amplitude of each order as data determined for each of a plurality of permanent magnet temperatures. Specifically, as shown in FIG. 8A, the correlation data storage unit 36 stores the voltage amplitude when the horizontal axis is the β angle for the harmonic (for example, the third harmonic), and FIG. As shown in b), the phase when the horizontal axis is the β angle is stored. Details will be described later.

  As described above, the magnet temperature estimation unit 31 acquires the fundamental current idq output from the coordinate conversion unit 27 and the harmonic current idq_n output from the coordinate conversion unit 42, and based on these, the correlation data storage described above is obtained. The temperature Tm of the permanent magnet provided in the rotor of the motor 13 is estimated with reference to the data stored in the unit 36. A method for estimating the permanent magnet temperature will be described later.

  The magnet flux calculator 32 obtains the magnet flux Φa_Tm at the temperature Tm based on the temperature Tm of the permanent magnet estimated by the magnet temperature estimator 31. Since the temperature Tm of the permanent magnet and the magnet flux Φa uniquely correspond to each other, the magnet flux Φa can be determined based on the temperature Tm. The motor magnetic flux calculator 33 obtains the motor magnetic flux Φmtr generated in the motor 13 based on the magnet magnetic flux Φa and the fundamental current idq.

  The winding resistance calculator 34 receives the voltage command value vdq, the motor magnetic flux Φmtr, and the current idq, and calculates the winding resistance. That is, for the temperature estimation of the permanent magnet, the fundamental wave and the harmonic voltage are used, while for the winding resistance calculation, the fundamental wave voltage and current are used.

  Then, by estimating the temperature Tm of the permanent magnet, the state of the permanent magnet can be recognized, which can be used for improving the control performance of the motor 13 and protecting against demagnetization. On the other hand, it is possible to control overcurrent by estimating the winding temperature Tr. That is, when the estimated temperature reaches a preset threshold temperature, the output of the motor 13 can be reduced, or the motor 13 can be stopped, for example.

  Hereinafter, specific processing of magnet temperature estimation and winding temperature estimation according to the second embodiment will be described. In the second embodiment, the harmonic voltage vdq_n and the current idq_n are supplied to the magnet temperature estimation unit 31 as described above. Furthermore, a fundamental current idq is supplied. Then, by applying these numerical values to a map stored in the correlation data storage unit 36, the temperature Tm of the permanent magnet is estimated.

  As shown in FIG. 8A, the correlation data storage unit 36 stores a map indicating the relationship between the fundamental wave and the harmonics of each order, the β angle of the fundamental wave, the magnet temperature, and the voltage. ing. FIG. 8A shows a map of the third harmonic. Further, as shown in FIG. 8 (b), a map indicating the relationship between the β angle of the fundamental wave, the magnet temperature, and the voltage phase is stored for the fundamental wave and harmonics of each order. And the temperature Tm of a permanent magnet is estimated with reference to these maps. FIG. 8B shows a map of the third harmonic. Details will be described below.

  FIG. 8A is the same as FIG. 3A described above, and when the β angle and the phase voltage are determined, the temperature Tm of the permanent magnet can be estimated by applying to this map. . At this time, as apparent from FIG. 8A, the larger the β angle (closer to 90 deg), the greater the difference in phase voltage at each temperature. In other words, when the β angle is small, there is almost no difference in phase voltage at each temperature. That is, in the map shown in FIG. 8A, it is understood that the temperature estimation can be performed with higher accuracy as the β angle is larger.

  On the other hand, as is apparent from FIG. 8B, the voltage phase has a larger difference in voltage phase at each temperature as the β angle is smaller (closer to 0 deg). That is, according to the map shown in FIG. 8B, it can be said that the temperature estimation with higher accuracy is possible in the region where the β angle is smaller. Then, in the second embodiment, a threshold angle (for example, 45 deg) that is a break is set for the β angle, and when the angle is less than this threshold angle, the map of FIG. In some cases, the temperature Tm of the permanent magnet is estimated by referring to the map of FIG.

  For the estimation of the winding temperature, the same calculation method as in the first embodiment described above is used. That is, the winding temperature Tr of the armature coil is calculated by using (1) described above.

  In this way, in the motor control apparatus according to the second embodiment, the temperature Tm of the permanent magnet is estimated using the current supplied to the motor 13, the fundamental wave of the voltage, and the harmonics. The temperature Tm of the permanent magnet can be estimated without providing a sensor or the like. Therefore, the state of the permanent magnet can be recognized, which can be used for improving the control performance of the motor 13 and protecting against demagnetization. Further, the winding resistance Ra_Tr of the stator is obtained on the basis of the temperature Tm of the permanent magnet, and the fundamental wave of the current and voltage supplied to the motor 13, and consequently the winding temperature Tr is obtained. Overheating can be prevented.

  Here, in the present embodiment, when estimating the temperature Tm of the permanent magnet, the fundamental wave and the harmonic are used, and when calculating the winding resistance, only the fundamental wave is used without using the harmonic. ing. Therefore, it is possible to improve the estimation accuracy of the temperature Tm of the permanent magnet and further improve the calculation accuracy of the winding resistance.

  Furthermore, in this embodiment, as shown in FIGS. 8A and 8B, the correlation data storage unit 36 has a map showing the relationship between the β angle and the phase voltage, and the relationship between the β angle and the voltage phase. The map shown is memorized. Then, since the magnet temperature is estimated by selecting two maps according to the size of the β angle, a more accurate temperature estimation is possible.

[Description of Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 9A is a block diagram showing a configuration of the control unit 15-3 used in the motor control device according to the third embodiment of the present invention, and FIG. 9B is a temperature estimation according to the third embodiment. It is a block diagram which shows the structure of the device 16-3.

  The control unit 15-3 shown in FIG. 9A supplies a DC voltage to the control unit 15-2 shown in FIG. 7A described above, that is, a DC superimposition for superimposing a DC component. The difference is that a DC voltage vmp_dc output from the DC superimposing unit 51 is supplied to the adder 41 and a DC detecting unit 52 is provided. Since other configurations are the same as those in FIG. 7A, the same reference numerals are given and description of the configurations is omitted. The DC detection unit 52 detects a DC current imp_dc from the current imp detected by the current sensor 25.

  On the other hand, as shown in FIG. 9B, the temperature estimator 16-3 includes a magnet temperature estimation unit 31 that estimates the temperature Tm of the permanent magnet provided in the rotor of the motor 13, and a magnet that calculates the magnet magnetic flux Φa_Tm at the temperature Tm. A magnetic flux calculation unit 32 and a correlation data storage unit 36 are provided. The magnet temperature estimation unit 31 estimates the temperature Tm of the permanent magnet by the same method as in the second embodiment described above.

  In addition, a winding resistance calculation unit 34a and a winding temperature estimation unit 35 are provided. The winding resistance calculation unit 34a uses a DC voltage vmp_dc output from the DC superimposing unit 51 as a frequency component lower than the harmonic of the order used for the temperature estimation of the permanent magnet by the magnet temperature estimation unit 31, and a DC detection unit 52. The winding resistance Ra_Tr of the armature coil is obtained on the basis of the direct current imp_dc detected in (1). As is well known, the winding resistance R (tr) at the temperature tr can be obtained by the following equation (3).

R (tr) = vmp_dc / imp_dc (3)
Thereafter, the winding temperature estimation unit 35 estimates the winding temperature Tr based on the winding resistance Ra_Tr. As in the first and second embodiments described above, by estimating the temperature Tm of the permanent magnet, the demagnetization state of the permanent magnet can be recognized, which is useful for improving the control performance of the motor 13 and protecting against demagnetization. Is possible. On the other hand, it is possible to control overcurrent by estimating the winding temperature Tr. That is, when the estimated temperature reaches a preset threshold temperature, the output of the motor 13 can be reduced, or the motor 13 can be stopped, for example.

  In this way, in the motor control device according to the third embodiment, the magnet temperature is estimated using the current supplied to the motor 13, the fundamental wave of the voltage, and the harmonics, so a temperature sensor or the like is provided for the permanent magnet. The temperature Tm of the permanent magnet can be estimated without providing it. Therefore, the demagnetization state of the permanent magnet can be recognized, which can be used for improving the control performance of the motor 13 and protecting the demagnetization.

  Further, the DC voltage vmp_dc is superimposed on the voltage command for driving the inverter circuit 12, and further, the DC current imp_dc included in the detected current is detected, and using these DC voltage vmp_dc and DC current imp_dc, winding resistance Is calculated, and the winding temperature Tr is estimated. Therefore, it is possible to estimate the winding temperature Tr with higher accuracy without being affected by the frequency.

[Description of Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. FIG. 10A is a block diagram showing the configuration of the control unit 15-4 according to the fourth embodiment of the present invention, and FIG. 10B shows the configuration of the temperature estimator 16-4 according to the fourth embodiment. FIG.

  The control unit 15-4 illustrated in FIG. 10A is different from the above-described FIG. 7A in that the harmonic current command value idq_n_ref is set to be zero. That is, the dq_n current control unit 43 controls the harmonic current flowing through the motor 13 to be zero. That is, the dq_n current control unit 43 has a function as current suppression means for controlling the voltage command value of the motor 13 so as to suppress the harmonic current flowing through the motor 13. Other configurations are the same as those in FIG. 7A described in the second embodiment. Further, the temperature estimator 16-2 shown in FIG. 10B is different in that the data supplied to the magnet temperature estimation unit 31 does not include the harmonic current idq_n, and the other configurations are the same as those in FIG. It is the same. Therefore, the same parts are denoted by the same reference numerals, and the description of the configuration is omitted.

  Next, the operation of the motor control apparatus according to the fourth embodiment will be described with reference to the flowchart shown in FIG. In the fourth embodiment, the output voltage of the inverter circuit 12 is controlled so that the harmonics included in the current imp detected by the current sensor 25 become zero. By doing so, it is possible to estimate the temperature of the permanent magnet and the temperature of the winding without flowing unnecessary harmonic current.

  First, in step S11 of FIG. 11, the current of the nth harmonic is suppressed. That is, by supplying a current command value at which idq_n_ref = 0 shown in FIG. 10A, the current of the nth harmonic flowing in the motor 13 is suppressed.

  Next, in step S12, the amplitude and phase of the nth harmonic voltage are detected. Thereafter, in step S13, the magnet temperature estimation unit 31 estimates the temperature Tm of the permanent magnet with reference to the correlation data stored in the correlation data storage unit 36 based on the preset β angle. To do. That is, as described above, when the β angle serving as the break is 45 deg, the temperature Tm of the permanent magnet is estimated based on the phase of the phase voltage (see FIG. 8B) when the β angle is less than 45 deg. To do. On the other hand, when the β angle is 45 deg or more, the temperature Tm of the permanent magnet is estimated based on the amplitude of the phase voltage (see FIG. 8A).

  In step S <b> 14, the magnet magnetic flux calculator 32 calculates the magnet magnetic flux Φa_Tm based on the temperature Tm estimated by the magnet temperature estimator 31.

  In step S15, the winding resistance calculator 34 detects the current and voltage of the fundamental wave. In step S16, the winding resistance calculator 34 calculates the winding resistance Ra_Tr. The calculation method at this time is calculated using the above-described equation (1). Thereafter, in step S17, the winding temperature estimation unit 35 estimates the winding temperature Tr based on the winding resistance Ra_Tr.

  Thus, in the motor control device according to the fourth embodiment, the harmonic current is suppressed (controlled not to flow), the current supplied to the motor 13, the fundamental wave of the voltage, and the harmonics. Detect waves. And since the temperature Tm of a permanent magnet is estimated using the detected electric current and voltage, the temperature Tm of a permanent magnet can be estimated, without installing a temperature sensor etc. Therefore, the demagnetization state of the permanent magnet can be recognized, and the motor can be controlled with high accuracy.

  Further, the winding resistance of the armature coil is obtained on the basis of the temperature Tm of the permanent magnet, and the fundamental wave of the current and voltage supplied to the motor 13, and consequently the winding temperature Tr is obtained. Can be prevented from overheating. Furthermore, since the harmonic current is suppressed, the influence of the harmonic current flowing through the control circuit can be avoided, and the motor 13 can be controlled with higher accuracy.

  When the β angle is small (for example, less than 45 deg), the temperature Tm of the permanent magnet is estimated based on the phase voltage phase, and when the β angle is large (for example, 45 deg or more), based on the phase voltage amplitude. Since the temperature Tm of the permanent magnet is estimated, more accurate temperature estimation is possible.

[Description of Modified Example of Fourth Embodiment]
Next, a modification of the above-described fourth embodiment will be described. In the above-described fourth embodiment, a break angle is set for the β angle, and if it is less than the break β angle, the temperature of the permanent magnet is estimated based on the phase voltage phase, and if the β angle is greater than the β angle, the amplitude of the phase voltage is estimated. Based on the above, the temperature Tm of the permanent magnet was estimated.

  In contrast, in the modification, the phase T of the phase voltage and the amplitude are weighted according to the β angle, and the temperature Tm of the permanent magnet is estimated. Hereinafter, the processing procedure of the modification will be described with reference to the flowchart shown in FIG. In FIG. 12, the same step number is assigned to the same process as the step number shown in FIG.

  First, in step S11 of FIG. 12, the nth harmonic current is suppressed. Next, in step S12, the amplitude and phase of the nth harmonic voltage are detected. In step S12a, the magnet temperature estimation unit 31 performs weighting processing. In this weighting, the voltage amplitude and the phase are weighted by multiplying by a coefficient that changes linearly as the β angle increases. For example, the weighting factor x1 is set to 100% when the β angle is 0 deg and 0% when the β angle is 90 deg with respect to the phase of the phase voltage. For example, when the β angle is 18 deg, the weighting factor x1 is 80%. Then, the temperature Tm of the permanent magnet is estimated based on both the phase of the phase voltage and the amplitude. That is, the larger the β angle is, the smaller the influence of the harmonic voltage phase is set. Or it sets so that the influence of a harmonic voltage amplitude and a fundamental current amplitude may become large, so that (beta) angle becomes large.

  As a result, when the temperature Tm estimated based on the phase matches the temperature Tm estimated based on the amplitude, the temperature becomes the estimated temperature. On the other hand, if the two estimated temperatures are different, the estimated temperatures are weighted and averaged according to the weighting factor. For example, when the β angle is 18 degrees, the temperature Tm estimated based on the phase is T1, and the temperature Tm estimated based on the amplitude is T2, “estimated temperature Tm = 0.8 * T2 + (1− 0.8) * T1 ".

  In step S13 of FIG. 12, the magnet temperature estimation unit 31 estimates the temperature Tm of the permanent magnet based on the weighted correlation data. Thereafter, similarly to FIG. 11 described above, the processing of steps S14 to S17 is executed to estimate the winding temperature.

  In this way, in the modification of the fourth embodiment, the ratio of the voltage phase contributing with the advance of the β angle is weighted. Therefore, it is possible to estimate the magnet temperature with higher accuracy in consideration of both the phase and the amplitude.

  In the above-described modification, the example in which the weighting factor x1 is calculated for the voltage phase has been described. However, the weighting factor x2 may be calculated for the voltage amplitude. Specifically, the weighting factor x2 is set so that the voltage amplitude is 0% when the β angle is 0 deg and 100% when the β angle is 90 deg. It is also possible to estimate the temperature of the permanent magnet using the weighting factor x2 set in this way. By doing so, it is possible to estimate the magnet temperature with higher accuracy in consideration of both the phase and the amplitude, as in the case of using the weighting factor x1 described above.

  The amplitude of the phase voltage is obtained with high accuracy when the load on the motor 13 is large. Therefore, when the load current flowing through the motor 13 is in the range from half of the maximum load to the maximum load, the above weighting factor is used. It is also possible to set x2. By doing so, it is possible to perform temperature estimation with higher accuracy.

  As mentioned above, although the control apparatus of the electric motor of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is substituted by the thing of the arbitrary structures which have the same function. be able to.

11 DC power supply 12 Inverter circuit 13 Motor (permanent magnet type motor)
14 Capacitor 15, 15-1, 15-2, 15-3, 15-4 Control Unit 16, 16-1, 16-2, 16-3, 16-4 Temperature Estimator 21 dq Current Control Unit 22 Non-interference Control Unit 23 Coordinate conversion unit 24 Modulation rate calculation unit 25 Current sensor 26 Multiple frequency component detection unit 27 Coordinate conversion unit 28 Subtractor 29 Adder 31 Magnet temperature estimation unit 32 Magnet flux calculation unit 33 Motor flux calculation unit 34, 34a Winding resistance Calculation unit 35 Winding temperature estimation unit 36 Correlation data storage unit 41 Adder 42 Coordinate conversion unit 43 dq_n current control unit 44 Coordinate conversion unit 45 Subtractor 51 DC superimposing unit 52 DC detection unit 101 Control device

Claims (9)

In a control device that controls driving of an electric motor including a rotor having a permanent magnet and a stator having an armature coil,
A fundamental wave detector that detects a fundamental wave that is a drive frequency of the electric motor;
A high frequency component detection unit for detecting a frequency component higher than the fundamental wave;
A correlation data storage unit that stores correlation data in which the voltage amplitude or voltage phase of the high-frequency component is associated for each β angle that is the phase of the current with respect to the induced voltage and the temperature of the permanent magnet;
Based on the fundamental wave detected by the fundamental wave detector and the high frequency component detected by the high frequency component detector, a magnet temperature estimator that estimates the temperature of the permanent magnet with reference to the correlation data;
A magnetic flux calculation unit that calculates the magnetic flux of the permanent magnet based on the temperature of the permanent magnet, and further calculates the motor magnetic flux based on the magnetic flux of the permanent magnet;
A winding estimation unit that estimates the winding resistance of the armature coil, or the winding temperature based on the motor magnetic flux, the fundamental wave, and the high-frequency component calculated by the magnetic flux calculation unit;
With
The winding estimation unit estimates the winding resistance or the winding temperature of the armature coil using a frequency component that is the same as or lower than the frequency of the high-frequency component used in the magnet temperature estimation unit. Control device. The motor control device according to claim 1, wherein the winding estimation unit estimates a winding resistance or a winding temperature using a fundamental wave as a frequency component lower than a high frequency component. A DC superimposing unit that superimposes the DC component, and a DC detecting unit that detects the DC component from the current flowing through the motor;
The motor control device according to claim 1, wherein the winding estimation unit estimates winding resistance or winding temperature using a direct current component as a frequency component lower than a high frequency component. A current suppression means for controlling a voltage command value of the motor so as to suppress a current of a high-frequency component flowing in the motor;
The magnet temperature estimation unit estimates the temperature of the permanent magnet based on a fundamental wave current detected by the fundamental wave detection unit and a voltage of a high frequency component detected by the high frequency component detection unit. The motor control device according to any one of claims 1 to 3.   The magnet temperature estimation unit estimates the magnet temperature using a fundamental wave current and a harmonic voltage of the order having a voltage having the largest amplitude as a high frequency component. The motor control device according to claim 1. The motors are motors having a phase number m and phases connected to each other at a neutral point,
The magnet temperature estimator estimates the magnet temperature using the lowest order harmonic voltage excluding the mth order harmonic among the harmonics generated in the motor as the fundamental current and the high frequency component. The motor control device according to claim 1, wherein the motor control device is a motor control device.   The magnet temperature estimation unit includes a correlation data storage unit that stores correlation data in which a voltage amplitude and a voltage phase of a high-frequency component are associated for each β angle and the temperature of the permanent magnet, and the permanent angle increases as the β angle increases. 7. The motor control device according to claim 1, wherein the setting is made such that the influence of the estimation based on the correlation data associated with the voltage phase is reduced in the estimation of the temperature of the magnet.   The magnet temperature estimation unit includes a correlation data storage unit that stores correlation data in which a voltage amplitude and a voltage phase of a high-frequency component are associated for each β angle and the temperature of the permanent magnet, and the permanent angle increases as the β angle increases. 7. The motor control device according to claim 1, wherein the estimation is performed so that the influence of the estimation based on the correlation data associated with the voltage amplitude is increased in the estimation of the temperature of the magnet.   9. The motor control device according to claim 8, wherein the load of the motor is set so that the influence of the voltage amplitude increases as the β angle increases in a range from half of the maximum load to the maximum load. .

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