JP2009296722A - Motor controller, motor control method, and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller which compensates torque ripple so that it may conform more to the actual ripple mode of the load torque. <P>SOLUTION: The motor controller 21 includes a memory 27, in which a command q-axis current correction for correcting a command q-axis current Iqref corresponding to each rotational angle is stored, and a q-axis current corrector 28, which reads out the command q-axis current correction from the memory 27, according to the rotational angle of a motor 4 and corrects the command q-axis current Iqref. The command q-axis current correction stored in the memory 27 is computed, based on the change of the rotational speed of the motor 4 in the preliminary measurement wherein the motor 4 is driven by connecting a dummy load device that generates the same torque as the torque of the load, under the same control conditions as the actual operation, excluding the point that the correcting operation is stopped. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor control device that controls a motor that drives a load whose torque varies periodically, a motor control method, and an air conditioner using the motor control device.

  For example, a refrigeration cycle used for a refrigerator, an air conditioner, etc. is composed of a compressor, a condenser, a decompressor, an evaporator, etc., and a variable capacity compressor is used to vary the cooling capacity of the refrigeration cycle. It has been. In the control of the rotational speed of the motor used in such a compressor, feedback control is performed so as to output a control amount corresponding to the difference between the target rotational speed and the actual rotational speed of the motor. In the conventional feedback control, the applied voltage is controlled a plurality of times during one rotation of the motor, so that the target rotation speed and the actual rotation speed are matched.

However, since the compressor has a large variation in load torque during one rotation, it is difficult to remove the torque variation by simple feedback control as described above, and the entire compressor vibrates in the rotational direction of the motor. There is a problem that it becomes a source of vibration and noise of a refrigerator, an air conditioner or the like equipped with this, and impairs the merchantability.
In order to solve such a problem, Patent Document 1 discloses a technique for compensating for fluctuations in load torque by adding a sinusoidal current as a current correction value to a q-axis current obtained by vector control of a motor. It is disclosed.
JP 2001-183017 A

  However, although the technique of Patent Document 1 can suppress vibration to some extent, there is a problem in that efficiency is lowered because an extra current flows. Further, since the variation mode of the load torque does not completely coincide with the sine wave, there is a limit to the level for suppressing vibration and the like.

  The present invention has been made in view of the above circumstances, and its object is to provide a motor control device, a motor control method, and the motor control capable of compensating for torque fluctuation so as to more closely match the actual load torque fluctuation mode. An object is to provide an air conditioner using the apparatus.

  In order to achieve the above object, a motor control device according to the present invention is a motor control device that controls a motor that drives a load whose torque fluctuates periodically, and that detects current flowing in the winding of the motor. Means for calculating a d-axis current that is an excitation component current and a q-axis current that is a torque component current based on the detected current, and a rotation speed of the motor matches a command rotation speed given from outside Speed control means for generating a command d-axis current and a command q-axis current, and current control for controlling the d-axis current and the q-axis current to match the command d-axis current and the command q-axis current Means for storing the command q-axis current correction value prepared for each rotation angle in order to correct the command q-axis current, and the storage means according to the rotation angle of the motor. The command q-axis current correction value is read out and the command q-axis current is corrected, and the command q-axis current correction value stored in the storage means generates the same torque as the torque of the load. It is a value calculated on the basis of a change in rotational speed of the motor and a moment of inertia of the motor in advance measurement in which a pseudo load device is connected and the correction operation by the correction means is stopped to drive the motor. It is characterized by.

  The motor control method of the present invention is a motor control method for controlling a motor that drives a load whose torque varies periodically, and detects a current flowing in the winding of the motor and based on the detected current. Thus, the d-axis current as the excitation current component and the q-axis current as the torque component current are obtained, and the command d-axis current and the command q-axis current are set so that the rotation speed of the motor matches the command rotation speed given from the outside. Generating and controlling so that the d-axis current and the q-axis current coincide with the command d-axis current and the command q-axis current, and generating the same torque as the torque of the load instead of the load Preliminary measurement for connecting the pseudo load device and driving the motor is performed, and the command q-axis current is determined based on the change in the rotational speed of the motor and the moment of inertia of the motor in the preliminary measurement. Calculating a positive value, when driving the load, and corrects the command q-axis current by the pre-command q-axis current correction value calculated by the measured corresponding to the rotation angle.

  According to the present invention, noise and vibration when driving a load are suppressed and driving efficiency is improved by controlling the motor by compensating for torque fluctuation so as to more closely match the actual load torque fluctuation mode. It becomes possible.

Hereinafter, an embodiment in which the present invention is applied to an apparatus for controlling a motor incorporated in a compressor of an air conditioner will be described with reference to the drawings.
FIG. 2 shows a schematic configuration of the refrigeration cycle of the air conditioner. As shown in FIG. 2, the compressor 2 (corresponding to a load) constituting the heat pump 1 of the air conditioner E is configured by housing the compression unit 3 and the motor 4 in the same iron hermetic container 5. The rotor shaft is connected to the compression portion 3. The compressor 2, the four-way valve 6, the indoor heat exchanger 7, the pressure reducing device 8, and the outdoor heat exchanger 9 are connected by a pipe that is a refrigerant passage so as to form a closed loop. The compressor 2 is, for example, a rotary compressor, and the motor 4 is, for example, a three-phase IPM (Interior Permanent Magnet) motor.

  During heating, the four-way valve 6 is in a state indicated by a solid line. For this reason, the high-temperature refrigerant | coolant compressed with the compression part 3 of the compressor 2 is supplied to the indoor side heat exchanger 7 from the four-way valve 6, and is condensed, Then, it decompresses by the decompression device 8, becomes low temperature and becomes outdoor heat It flows to the exchanger 9 where it evaporates and returns to the compressor 2. On the other hand, at the time of cooling, the four-way valve 6 is switched to a state indicated by a broken line. For this reason, the high-temperature refrigerant | coolant compressed by the compression part 3 of the compressor 2 is supplied to the outdoor heat exchanger 9 from the four-way valve 6, and is condensed, and after that, it is decompressed by the decompression device 8, becomes low temperature, and becomes indoor heat It flows to the exchanger 7 where it evaporates and returns to the compressor 2. The indoor side heat exchanger 7 and the outdoor side heat exchanger 9 are blown by fans 10 and 11, respectively. By this ventilation, heat exchange between the indoor side heat exchanger 7 and the outdoor side heat exchanger 9 and the indoor air and the outdoor air is efficiently performed.

  FIG. 1 is a functional block diagram showing the configuration of a motor control device 21 that vector-controls the rotation of the motor 4. In the vector control, the current flowing through the armature winding is separated into the magnetic flux direction of the permanent magnet, which is a field, and the direction orthogonal thereto, and these are adjusted independently to control the magnetic flux and the generated torque. For the current control, a current value represented by a coordinate system that rotates with the rotor of the motor 4, that is, a so-called dq coordinate system, is used, and the d-axis is a magnetic flux direction formed by a permanent magnet attached to the rotor, and q The axis is a direction orthogonal to the d-axis. The q-axis current Iq is a component that generates rotational torque (torque component current), and the d-axis current Id is a component that generates magnetic flux (excitation or magnetization component current).

  The motor control device 21 includes a current control unit 22, a rotational position estimation unit 23, a speed control unit 24, a PWM formation unit 25, an inverter circuit 26, a storage unit 27, and a q-axis current correction unit 28. The current control unit 22 includes subtractors 29d and 29q, PID controllers 30d and 30q, dq / αβ coordinate converter 31, αβ / UVW coordinate converter 32, UVW / αβ coordinate converter 33, and αβ / dq coordinate converter 34. It has. In the present embodiment, the current control means 35 is configured by the subtractors 29d and 29q and the PID controllers 30d and 30q, and the current calculation means 36 is configured by the UVW / αβ coordinate converter 33 and the αβ / dq coordinate converter 34. Is done.

  The inverter circuit 26 is a well-known voltage-type inverter formed by connecting switching elements such as IGBTs 26ap, 26an,... In a three-phase bridge circuit configuration, and is provided between each lower arm switching element and a negative DC power supply line. Is provided with a shunt resistor 26r. In the present embodiment, currents Iu, Iv, and Iw that flow in each phase (U phase, V phase, and W phase) of the motor 4 are detected based on the terminal voltage of each shunt resistor 26r. That is, in the present embodiment, each shunt resistor 26r corresponds to a current detection unit. In addition, as a current detection means, it is good also as a structure which provides the current detector which consists of Hall CT between the output terminal of the inverter circuit 26, and the terminal of the motor 4, for example.

  The currents Iu, Iv, Iw detected by the above configuration are converted into two-phase currents Iα, Iβ by the UVW / αβ coordinate converter 33. These two-phase currents Iα and Iβ are further converted into a d-axis current Id and a q-axis current Iq by an αβ / dq coordinate converter 34. α and β are coordinate axes of a biaxial coordinate system fixed to the stator of the motor 4. For the calculation of the coordinate conversion in the αβ / dq coordinate converter 34, an estimated rotation angle θe of the rotor (estimated value of phase difference between the α axis and the d axis) described later is used.

  The subtractor 29d subtracts the d-axis current Id from the command d-axis current Idref given from the speed control unit 24 to obtain the d-axis current deviation ΔId. The subtractor 29q subtracts the q-axis current Iq from the command q-axis current Iqref given from the speed control unit 24, and further adds the command q-axis current correction value given from the q-axis current correction unit 28 to add the q-axis current. Deviation ΔIq is obtained.

  The PID controllers 30d and 30q perform PID calculation on the d-axis current deviation ΔId and the q-axis current deviation ΔIq, and generate a command d-axis voltage Vd and a command q-axis voltage Vq expressed in the dq coordinate system. The command d-axis voltage Vd and the command q-axis voltage Vq are converted into values expressed in the α-β coordinate system by the dq / αβ coordinate converter 31, and each phase command voltage of the stator is further converted by the αβ / UVW coordinate converter 32. Converted to Vu, Vv, Vw. Note that the estimated rotation angle θe of the rotor is also used for calculation of coordinate conversion in the dq / αβ coordinate converter 31.

  The phase command voltages Vu, Vv, and Vw are input to the PWM forming unit 25. In the PWM forming unit 25, a gate drive signal subjected to pulse width modulation for supplying a voltage matching the command voltage is formed. The gate drive signal formed by the PWM forming unit 25 is given to the gates of the switching elements 26ap, 26an,... Constituting the inverter circuit 26, and thereby PWM modulated in accordance with the phase command voltages Vu, Vv, Vw. A three-phase AC voltage is generated and applied to the armature winding of the motor 4.

  In the above configuration, feedback control is performed by PID calculation by the subtractors 29d and 29q and the PID controllers 30d and 30q. Thereby, the d-axis current Id and the q-axis current Iq are controlled to coincide with the command q-axis current Iqref obtained by adding the command d-axis current Idref and the command q-axis current correction value, respectively.

  The rotational position estimating unit 23 estimates an estimated rotational angle θe (estimated rotational position) that is an estimated value of the rotational angle θ (rotational position) of the rotor and an estimated rotational speed ωe that is an estimated value of the rotational speed ω. , D-axis current Id, q-axis current Iq, and command d-axis voltage Vd are input. The rotational position estimation unit 23 stores values of d-axis inductance Ld, q-axis inductance Lq, and winding resistance value R of the armature winding, which are circuit constants of the motor 4.

Using these input values and circuit constants, the rotational position estimation unit 23 calculates an induced voltage estimated value Ed in the d-axis direction based on the following equation (1).
Ed = Vd-R.Id-Ld.p.Id + .omega.e.Lq.Iq (1)
Here, p is a differential operator. The rotational position estimation unit 23 executes PID calculation on the induced voltage estimated value Ed, and the result is output as the estimated rotational speed ωe of the rotor. According to this estimation method, the induced voltage estimated value Ed in the d-axis direction converges to zero. By integrating the estimated rotation speed ωe, the value is output as the estimated rotation angle θe. The estimated rotation speed ωe is given to the speed control unit 24.

  Command speed ωref output from an external control device (not shown) that controls the operation of the air conditioner is input to the speed control unit 24 (corresponding to speed control means). The subtractor 37q subtracts the estimated rotational speed ωe estimated by the rotational position estimating unit 23 from the command rotational speed ωref to obtain a speed deviation Δω, and the PID controller 38 executes a PID calculation on the speed deviation Δω to execute the command. A q-axis current Iqref is generated. The command d-axis current Idref is a constant value (zero in this embodiment). The command d-axis current Idref and the command q-axis current Iqref are given to the current control unit 22 and are controlled so that the d-axis current Id and the q-axis current Iq of the motor 4 coincide with those command values as described above. . As a result of the control as described above, the estimated rotational speed ωe matches the command rotational speed ωref.

  The storage unit 27 (corresponding to storage means) corresponds to the rotation angle of the motor 4 and the command q-axis current correction value for correcting the command q-axis current Iqref corresponding to each rotation angle (for example, every 1 degree). Correction data tabulated and stored. This correction data is calculated by a prior measurement described later. The q-axis current correction unit 28 performs a correction operation for correcting the command q-axis current Iqref based on the correction data. However, this correction operation is stopped at the time of preliminary measurement described later.

  The q-axis current correction unit 28 includes a rotation angle correction unit 39, a current correction unit 40, and an adjustment unit 41. The rotation angle correction unit 39 outputs a corrected estimated rotation angle θe ′ obtained by advancing the estimated rotation angle θe of the motor 4 estimated by the rotation position estimation unit 23 by a predetermined angle. The predetermined angle can be changed by the user. The current correction unit 40 reads the command q-axis current correction value corresponding to the correction estimated rotation angle θe ′ from the storage unit 27 and outputs the command q-axis current correction value to the adjustment unit 41. The adjustment unit 41 multiplies the given command q-axis current correction value by the adjustment coefficient and outputs the result to the subtractor 29q. This adjustment coefficient can be changed, for example, between 0.9 and 1.1. As a result, the user can finely adjust the command q-axis current correction value.

  Next, the prior measurement for calculating the command q-axis current correction value will be described with reference to FIGS. FIG. 3 is a functional block diagram showing the configuration for performing the prior measurement. As shown in FIG. 3, in this preliminary measurement, in addition to the motor 4 and the motor control device 21, a pseudo load device 51, a torque converter 52, an encoder 53, and a calculation means 54 are used. During the pre-measurement, the motor control device 21 executes the feedback control described above and controls the driving of the motor 4. At this time, however, the correction operation of the command q-axis current Iqref by the q-axis current correction unit 28 is stopped.

  The pseudo load device 51 generates the same torque (equivalent torque) as the load torque of the compressor 2 driven by the motor 4, and the load motor 55, converter 56, electronic load device 57, and pseudo load waveform generator 58. And an encoder 59. The load motor 55 is, for example, a three-phase brushless motor, and the rotation shaft thereof is connected to the rotation shaft of the motor 4 via the torque converter 52. A converter 56 is connected to a terminal of the load motor 55. The converter 56 converts the three-phase AC voltage supplied from the load motor 55 into a DC voltage and applies it to the electronic load device 57. The electronic load device 57 changes its equivalent resistance value according to the data given from the pseudo load waveform generator 58.

  FIG. 4 shows a typical load torque variation pattern of the compressor 2. The four variation patterns A to D shown in FIG. 4 are, for example, when the compressor 2 is driven at a low speed, and show two patterns during the cooling operation of the air conditioner E and two patterns during the heating operation. The pseudo load waveform generator 58 stores such load torque fluctuation patterns A to D. The pseudo load waveform generator 58 is an electronic load device 57 in accordance with the rotation angle of the load motor 55 supplied from the encoder 59 so that the pseudo load device 51 generates load torque having the stored variation patterns A to D. Set the resistance value.

  With this configuration, when the motor 4 is driven, the load motor 55 operates as a generator, and the electric power output from the load motor 55 is consumed in the electronic load device 57 via the converter 56. Thereby, a load torque that changes in accordance with a change in the resistance value of the electronic load device 57 is added to the motor 4. In other words, the load torque of the compressor 2 is added to the motor 4 in a pseudo manner. Therefore, the motor control device 21 operates under the same conditions as those in the actual operation in which the compressor 2 is driven by the motor 4 except that the operation for correcting the command q-axis current Iqref is not performed.

By performing such an operation, the motor 4 undergoes rotational speed fluctuations accompanying torque fluctuations. The computing means 54 obtains a command q-axis current correction value based on the fluctuation of the rotational speed as follows. That is, the encoder 53 outputs the rotational speed ω of the motor 4 during the operation to the calculation means 54. The calculation means 54 calculates a torque deviation ΔT between the torque T generated by the motor 4 and the load torque TL based on the input rotational speed ω of the motor 4, the inertia moment Jm_1 of the motor 4 and the inertia moment Jm_2 of the load motor 55. Calculate. This torque deviation ΔT is expressed by the following equation (2).
ΔT = T−TL = (Jm_1 + Jm_2) · dω / dt (2)

  In the above equation (2), the reason why the moment of inertia Jm_2 of the load motor 55 is used is as follows. In the above configuration, the torque generated by the pseudo load device 51 is applied to the motor 4 via the rotation shaft of the load motor 55. For this reason, the torque applied to the motor 4 is affected by the moment of inertia Jm_2 of the load motor 55. Therefore, in this embodiment, in order to compensate for this influence, the torque deviation ΔT is calculated using a value obtained by adding the inertia moment Jm_2 of the load motor 55 to the inertia moment Jm_1 of the motor 4.

  When the torque T generated by the motor 4 and the load torque TL match (when the torque deviation ΔT is zero), the rotational speed ω does not vary. Therefore, the command q-axis current correction value is a q-axis current value necessary for making the torque deviation ΔT zero, that is, a q-axis current value for generating torque having a phase opposite to the torque deviation ΔT. Therefore, the computing means 54 obtains the command q-axis current correction value by multiplying the torque deviation ΔT by −1 and further dividing by the torque constant KT of the motor 4.

  The calculating means 54 calculates the command q-axis current correction value as described above for each rotation angle θ of the motor 4 given from the encoder 53. The calculation of the command q-axis current correction value is performed every time the load torque having the variation patterns A to D shown in FIG. 4 is generated. The calculation means 54 stores correction data (corresponding to a command q-axis current correction value) in a table in which the calculation result and each rotation angle are associated with each other and stored in the storage unit 27 of the motor control device 21. The calculation means 54 may be any means that performs the above calculation, and may be constituted by, for example, a microcomputer or a personal computer.

  Next, an operation when the motor 4 is controlled using the motor control device 21 in a state where the correction data obtained in this way is stored in the storage unit 27 will be described with reference to FIG. FIG. 5 is a flowchart showing the flow of control by the motor control device 21. First, the motor control device 21 starts the motor 4 by, for example, forced commutation (step S1). Thereafter, the rotational speed of the motor 4 is feedback-controlled based on a command rotational speed ωref given from an external control device that controls the operation of the air conditioner E (steady operation state, step S2).

  In subsequent steps S3 and S4, in the q-axis current correction unit 28, the current correction unit 40 reads the command q-axis current correction value from the storage unit 27 according to the correction estimated rotation angle θ ′ given from the rotation angle correction unit 39, The result is output to the subtractor 29q via the adjustment unit 41. At this time, the current correction unit 40 reads out the command q-axis current correction value of the type closest to the driving state (operating state) of the compressor 2. As a result, the command q-axis current correction value is added to the command q-axis current Iqref. By repeatedly executing such steps S3 and S4 in the steady operation state, fluctuations in the rotational speed of the motor 4 due to fluctuations in the load torque of the compressor 2 are suppressed.

  As described above, the motor control device 21 of the present embodiment includes the storage unit 27 that stores the command q-axis current correction value for correcting the command q-axis current Iqref corresponding to each rotation angle, and the motor 4. A q-axis current correction unit 28 that reads the command q-axis current correction value from the storage unit 27 according to the rotation angle and corrects the command q-axis current Iqref is provided. The command q-axis current correction value stored in the storage unit 27 is a pseudo load device 51 that generates the same load torque as that of the compressor 2 under the same control conditions as in actual operation except that the correction operation is stopped. Was calculated based on the change in the rotational speed of the motor 4 and the moment of inertia Jm_1 of the motor 4 in the prior measurement when the motor 4 was driven.

  According to such a configuration, it is possible to suppress the rotational speed fluctuation accompanying the load torque fluctuation of the compressor 2 in consideration of the rotational speed fluctuation due to various factors (control delay or the like) in the control during actual operation. That is, the torque fluctuation can be compensated so as to more closely match the actual load torque fluctuation mode. Further, by controlling the motor 4 while compensating for torque fluctuations, it is possible to suppress noise and vibration when driving the compressor 2 and improve driving efficiency.

  In the pre-measurement, the motor 4 is operated as a generator by the load motor 55 in which the rotating shafts are connected, and the generated electric power is consumed by the electronic load device 57 having a variable resistance value. The load torque TL is added. The torque deviation ΔT between the torque T generated by the motor 4 and the load torque TL at this time is calculated based on the rotational speed ω of the motor 4, the inertia moment Jm_1 of the motor 4, and the inertia moment Jm_2 of the load motor 55, The command q-axis current correction value is obtained from this torque deviation ΔT.

  Thus, even when the load torque TL same as the load torque of the compressor 2 is applied to the motor 4 via the rotation shaft of the load motor 55, the influence of the inertia moment Jm_2 of the load motor 55 is taken into consideration. Since the command q-axis current correction value is calculated, the torque fluctuation can be compensated so as to more closely match the actual load torque fluctuation mode. Note that the moment of inertia of the compressor 2 during actual operation is not considered in the present embodiment because it is considered to be small enough not to affect the compensation of torque fluctuation. However, if this point is also taken into consideration, the torque fluctuation The accuracy of compensation can be further improved.

  An adjustment unit 41 that multiplies the command q-axis current correction value given from the current correction unit 40 by a changeable adjustment coefficient and outputs the result to the subtractor 29q is provided. Thus, for example, in the inspection process of the motor control device 21, if the adjustment coefficient is set to a value that minimizes the rotational speed fluctuation of the motor 4 while the motor 4 is driven under the same conditions as in actual operation, Even if the calculated command q-axis current correction value is not optimal, it is possible to prevent a reduction in accuracy of torque fluctuation compensation.

  A rotation angle correction unit 39 that outputs a corrected estimated rotation angle θe ′ obtained by advancing the estimated rotation angle θe of the motor 4 by a predetermined angle to the current correction unit 40 is provided. Thereby, a delay due to the calculation processing of the q-axis current correction unit 28, a delay in speed estimation by the rotational position estimation unit 23, and the like can be compensated. Instead of providing the rotation angle correction unit 39, the rotation angle in the correction data stored in the storage unit 27 may be advanced by a predetermined angle.

  Command q-axis current correction values corresponding to the load torques of the four variation patterns A to D are stored in the storage unit 27, and among these, the q-axis current correction unit 28 selects the type closest to the driving state of the compressor 2. Read out. In this way, it is possible to perform torque fluctuation compensation in consideration of various driving conditions of the load during actual operation.

The present invention is not limited to the embodiment described above and illustrated in the drawings, and the following modifications or expansions are possible.
The rotation angle correction unit 39 and the adjustment unit 41 in the q-axis current correction unit 28 may not be provided when there is no problem in the accuracy of torque fluctuation compensation. In that case, the current correction unit 40 may read the command q-axis current correction value from the storage unit 27 in accordance with the estimated rotation angle θe output from the rotation position estimation unit 23 and output it to the subtractor 29q.
The estimation method of the rotation speed and the rotation angle is not limited to the estimation method by the rotation position estimation unit 23 that converges the induced voltage estimated value Ed in the d-axis direction to zero.

In the preliminary measurement, the variation pattern of the load torque stored in the pseudo load waveform generator 58 may be, for example, three or less, or five or more. However, when only one variation pattern is stored, the most typical variation pattern of the load torque of the compressor 2 is preferable.
Any one of the encoders 53 and 59 in the configuration for performing the preliminary measurement may be provided. In that case, the output of one encoder may be given to both the computing means 54 and the pseudo load waveform generator 58. The prior measurement is performed by connecting the load motor 55 to which the electronic load device 57 is connected to the rotating shaft of the motor 4, but not limited to this, a pseudo load that generates the same load torque as the load torque of the compressor 2. Any configuration may be used as long as the devices are connected. Moreover, it replaces with a prior measurement and the simulation performed on the conditions similar to a prior measurement may be implemented, and instruction | command q-axis current correction value may be calculated.

  The compressor 2 is not limited to the rotary type, and may be, for example, a reciprocating type compressor. The present invention is not limited to the configuration that controls the motor 4 of the compressor 2 of the air conditioner E, and may be applied to a configuration that controls the motor of the compressor of the refrigerator, for example. That is, the present invention can be applied to any configuration that controls a motor that drives a load whose torque varies periodically.

The functional block diagram of the motor control apparatus which shows one Embodiment of this invention Diagram showing refrigeration cycle of air conditioner Functional block diagram showing the configuration when performing pre-measurement Diagram showing typical torque fluctuation pattern of compressor Flow chart showing control contents of motor control device

Explanation of symbols

  In the drawings, 1 is a heat pump, 2 is a compressor (load), 4 is a motor, 7 is an indoor heat exchanger, 8 is a decompression device, 9 is an outdoor heat exchanger, 21 is a motor control device, and 24 is a speed control unit. (Speed control means), 26r is a shunt resistance (current detection means), 27 is a storage section (storage means), 28 is a q-axis current correction section (correction means), 35 is current control means, 36 is current calculation means, 39 Is a rotation angle correction unit (rotation angle correction means), 41 is an adjustment unit (adjustment means), 51 is a pseudo load device, 55 is a load motor, 57 is an electronic load device, and E is an air conditioner.

Claims (11)

A motor control device for controlling a motor that drives a load whose torque varies periodically,
Current detection means for detecting a current flowing in the winding of the motor;
Current calculation means for obtaining a d-axis current as an excitation component current and a q-axis current as a torque component current based on the detected current;
Speed control means for generating a command d-axis current and a command q-axis current so that the rotation speed of the motor matches a command rotation speed given from outside;
Current control means for controlling the d-axis current and the q-axis current to coincide with the command d-axis current and the command q-axis current;
Storage means for storing a command q-axis current correction value prepared corresponding to each rotation angle in order to correct the command q-axis current;
Correction means for reading out the command q-axis current correction value from the storage means according to the rotation angle of the motor and correcting the command q-axis current;
The command q-axis current correction value stored in the storage means is measured in advance by connecting a pseudo load device that generates the same torque as the load torque and stopping the correction operation by the correction means to drive the motor. A motor control device characterized in that the value is calculated based on a change in rotational speed of the motor and an inertia moment of the motor. The command q-axis current correction value stored in the storage means is
It is a value obtained by multiplying the rate of change of the rotational speed of the motor obtained in the prior measurement by -1 and the moment of inertia of the motor, and further dividing by the torque constant of the motor. The motor control device according to claim 1. The pseudo load device is constituted by a load motor to which an electronic load device is attached,
3. The motor according to claim 1, wherein in the preliminary measurement, the command q-axis current correction value is calculated using a value obtained by adding an inertia moment of the load motor to an inertia moment of the motor. Control device.   4. The motor control device according to claim 1, wherein the correction unit includes an adjustment unit that adjusts the magnitude of the command q-axis current correction value read from the storage unit. 5.   The correction unit includes a rotation angle correction unit that inputs a rotation angle of the motor and outputs a corrected rotation angle, and reads the command q-axis current correction value corresponding to the corrected rotation angle from the storage unit. The motor control device according to any one of claims 1 to 4. The storage means stores a plurality of types of the command q-axis current correction values corresponding to the driving state of the load,
6. The correction unit according to claim 1, wherein the correction unit reads out the command q-axis current correction value of the type closest to the driving state of the load from the storage unit and corrects the command q-axis current. The motor control apparatus described. A heat pump comprising a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger connected by a refrigerant passage;
The motor which drives the said compressor is controlled by the motor control apparatus in any one of Claim 1 thru | or 6. The air conditioner characterized by the above-mentioned. A motor control method for controlling a motor that drives a load whose torque varies periodically,
The current flowing through the motor winding is detected, and the d-axis current as the excitation current component and the q-axis current as the torque component current are obtained based on the detected current, and the rotational speed of the motor is given from the outside. A command d-axis current and a command q-axis current are generated so as to match the command rotational speed, and control is performed so that the d-axis current and the q-axis current match the command d-axis current and the command q-axis current. In things,
In place of the load, a pseudo load device that generates the same torque as the torque of the load is connected to perform a preliminary measurement for driving the motor, and a change in the rotation speed of the motor and a moment of inertia of the motor in the preliminary measurement Command q-axis current correction value is calculated based on
When driving the load, the command q-axis current is corrected by the command q-axis current correction value calculated in the preliminary measurement corresponding to each rotation angle.   The command q-axis current correction value is obtained by multiplying the rate of change of the rotational speed of the motor obtained in the prior measurement by −1 and the moment of inertia of the motor, and further dividing by the torque constant of the motor. 9. The motor control method according to claim 8, wherein the motor control method is calculated. When the pseudo load device is constituted by a load motor to which an electronic load device is attached,
10. The motor control according to claim 8, wherein, in the preliminary measurement, the command q-axis current correction value is calculated using a value obtained by adding the inertia moment of the load motor to the inertia moment of the motor. Method. In the preliminary measurement, a plurality of types of the command q-axis current correction values according to the driving state of the load are calculated,
11. When driving the load, the command q-axis current is corrected based on the command q-axis current correction value of the type closest to the driving state of the load. Motor control method.

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